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Sample records for field qaidam basin

  1. Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The purpose of this paper is to analyze the regional fault systems of Qaidam basin and adjacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault systems occurred in the Qaidam and adjacent mountain belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunlun Mountain fault system; (3)Altun strike-slip fault system; (4)Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accumulation belt.

  2. Characteristics of Abnormal Pressure Systems and Their Responses of Fluid in Huatugou Oil Field, Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaozhi; XU Hao; TANG Dazhen; ZHANG Junfeng; HU Xiaolan; TAO Shu; CAI Yidong

    2009-01-01

    Based on the comprehensive study of core samples, well testing data, and reservoir fluid properties, the construction and the distribution of the abnormal pressure systems of the Huatugou oil field in Qaidam Basin are discussed. The correlation between the pressure systems and hydrocarbon accumulation is addressed by analyzing the corresponding fluid characteristics. The results show that the Huatugou oil field as a whole has low formation pressure and low fluid energy; therefore, the hydrocarbons are hard to migrate, which facilitates the forming of primary reservoirs. The study reservoirs, located at the Xiayoushashan Formation (N_2~1) and the Shangganchaigou Formation (N_1) are relatively shallow and have medium porosity and low permeability. They are abnormal low-pressure reservoirs with an average formation pressure coefficient of 0.61 and 0.72 respectively. According to the pressure coefficient and geothermal anomaly, the N_1 and N_2~1 Formations belong to two independent temperature-pressure systems, and the former has slightly higher energy. The low-pressure compartments consist of a distal bar as the main body, prodeita mud as the top boundary, and shore and shallow lake mud or algal mound as the bottom boundary. They are vertically overlapped and horizontally paralleled. The formation water is abundant in the Cl~- ion and can be categorized as CaCl_2 type with high salinity, which indicates that the abnormal low-pressure compartments are in good sealing condition and beneficial for oil and gas accumulation and preservation.

  3. Quantitative calculation of GOR of complex oil-gas-water systems with logging data: A case study of the Yingdong Oil/Gas Field in the Qaidam Basin

    OpenAIRE

    2014-01-01

    In the Yingdong Oil/Gas Field of the Qaidam Basin, multiple suites of oil-gas-water systems overlie each other vertically, making it difficult to accurately identify oil layers from gas layers and calculate gas-oil ratio (GOR). Therefore, formation testing and production data, together with conventional logging, NMR and mud logging data were integrated to quantitatively calculate GOR. To tell oil layers from gas layers, conventional logging makes use of the excavation effect of compensated ne...

  4. Chlorine isotopic geochemistry of salt lakes in the Qaidam Basin, China

    Digital Repository Service at National Institute of Oceanography (India)

    Liu, W.G.; Xiao, Y.K.; Wang, Q.Z.; Qi, H.P.; Wang, Y.H.; Zhou, Y.M.; Shirodkar, P.V.

    The isotopic compositions of chlorine in salt lake brine coexisting with halite, oil-field water and river water from the Qaidam Basin (Qinghai, China) have been examined using high-precision measurement of chlorine isotopes based on thermal...

  5. OIL RESOURCES EXPLORATION AND POTENTIAL OF QAIDAM BASIN

    Institute of Scientific and Technical Information of China (English)

    Yin Chengming; Jiang Bo; Han Qinpeng; Wu Jianfeng

    2007-01-01

    @@ Located in the northern Qinghai-Tibet plateau, Qaidam Basin is surrounded by the East Kunlun Mountains in the south, Qilian Mountains in the north, and Altun Mountains in the west. With an area of 121,000 square kilometers (km2), Qaidam Basin is about 850 kilometers (km) long from east to west and 150~300 km wide from south to north.

  6. First quantification of severe wind erosion in yardang fields using cosmogenic 10Be within the western Qaidam Basin, China

    Science.gov (United States)

    Rohrmann, A.; Heermance, R.; Kapp, P. A.; Mc-Callister, A.

    2010-12-01

    Desert environments are a major source of global loess and may undergo substantial wind-erosion as evidenced by yardangs, which are streamlined bedrock ridges sculpted from uni-directional winds. However, there are few quantitative estimates of wind erosion rates in deflationary deserts, globally. Here, we report the first quantitative rates of bedrock wind erosion determined using cosmogenic 10Be in the western Qaidam basin, China, where roughly one-third of the modern basin floor (~3.88 × 104 km2) exposes yardangs. Eleven Neogene bedrock sandstone samples and one pre-Cenozoic granite sample were analyzed for 10Be concentrations. The Neogene samples were collected from crests and limbs of broad and actively growing anticlines, where in most places strata have been wind-sculpted into yardangs. Sedimentary bedrock erosion rates vary from 0.04-0.34 mm/yr, although 60 percent (n=7) of all samples cluster tightly at 0.1 ± 0.03 mm/yr. Erosion rates assume steady-state erosion over ~10,000 years. The lowest rate of 0.0025 mm/yr was obtained from a granite bedrock sample along the Altyn-Tagh range bounding the northwestern margin of the Qaidam basin and is consistent with other 10Be bedrock erosion rates collected from granitic bedrock elsewhere on the Tibetan Plateau. These results demonstrate the importance of lithology in controlling bedrock erodibility by wind. The highest erosion rates of 0.17, 0.25, and 0.34 mm/yr were determined along a transect across an active anticline. The lowest of the three rates was obtained from the top of the structure, suggesting that wind erosion and thus wind speeds are highest on the limbs of an anticline as wind is forced around the obstacle (Bernoulli-effect), rather than flowing over it. The determined sedimentary bedrock erosion rates of 0.04-0.34 mm/yr are in good agreement with previous analysis of basin wide-average erosion rates from geological cross-sections (0.29 mm/yr) and simple erosion calculations using previous lake

  7. Structural deformation pattern within the NW Qaidam Basin in the Cenozoic era and its tectonic implications

    Science.gov (United States)

    Mao, Liguang; Xiao, Ancheng; Zhang, Hongwei; Wu, Zhankui; Wang, Liqun; Shen, Ya; Wu, Lei

    2016-09-01

    The Qaidam Basin is located in the northeastern Tibetan Plateau and provides an excellent field laboratory in understanding the history and mechanism of the plateau growth. It deformed widely over the northwest during the Cenozoic but with little thrust loading along the margins, where no foreland depression is observed. Based on satellite images, seismic and borehole data, we investigated the structural deformation pattern (including the structural style and timing of deformation) and its formation mechanism within the northwestern Qaidam Basin during the Cenozoic era. Mapping of surface geology shows that the modern Qaidam Basin is characterized by five SE-trending anticlinal belts. Each belt consists of several right-step en echelon anticlines with plenty of normal and strike-slip faults crossing the crests. Those anticlines are generally dominated by double fault systems at different depths: an upper thrust fault system, controlling the anticlines identified on the surface and a lower dextral transpressional fault system characterized by typical flower structures. They are separated by weak layers in the upper Xiaganchaigou or the Shangganchaigou formations. The upper system yields shortening strain 2-5 times larger than that of the lower system and the additional strain is interpreted to be accommodated by hinge-parallel elongation in the upper system. Growth strata indicate that deformation within the Qaidam Basin initiated in the middle Miocene ( 15 Ma) and accelerated in the late Miocene ( 8 Ma). A simple Riedel-P-Shear model is used to explain the deformation mechanism within the northwestern Qaidam Basin.

  8. Quantitative calculation of GOR of complex oil-gas-water systems with logging data: A case study of the Yingdong Oil/Gas Field in the Qaidam Basin

    Directory of Open Access Journals (Sweden)

    Sima Liqiang

    2014-12-01

    Full Text Available In the Yingdong Oil/Gas Field of the Qaidam Basin, multiple suites of oil-gas-water systems overlie each other vertically, making it difficult to accurately identify oil layers from gas layers and calculate gas-oil ratio (GOR. Therefore, formation testing and production data, together with conventional logging, NMR and mud logging data were integrated to quantitatively calculate GOR. To tell oil layers from gas layers, conventional logging makes use of the excavation effect of compensated neutron log, NMR makes use of the different relaxation mechanisms of light oil and natural gas in large pores, while mud logging makes use of star chart of gas components established based on available charts and mathematical statistics. In terms of the quantitative calculation of GOR, the area ratio of the star chart of gas components was first used in GOR calculation. The study shows that: (1 conventional logging data has a modest performance in distinguishing oil layers from gas layers due to the impacts of formation pressure, hydrogen index (HI, shale content, borehole conditions and invasion of drilling mud; (2 NMR is quite effective in telling oil layers from gas layers, but cannot be widely used due to its high cost; (3 by contrast, the star chart of gas components is the most effective in differentiating oil layers from gas layers; and (4 the GOR calculated by using the area ratio of star chart has been verified by various data such as formation testing data, production data and liquid production profile.

  9. Longitudinal distributions of two formation pathways of biogenic gases in continental deposits: A case study from Sebei 1 gas field in the Qaidam Basin, western China

    Institute of Scientific and Technical Information of China (English)

    SHUAI YanHua; ZHANG ShuiChang; ZHAO WenZhi; SU AiGuo; WANG HuiTong

    2007-01-01

    The distribution of two formation pathways of biogenic methane, acetate fermentation and reduction of CO2, has been extensively studied. In general, CO2 reduction is the dominate pathway in marine environment where acetate is relatively depleted because of SRB consuming. While in terrestrial freshwater or brackish environment, acetate fermentation is initially significant, but decreases with increasing buried depth. In this paper, character of biogenic gases is profiled in the XS3-4 well of the Sebei 1 gas field in the Sanhu depression, Qaidam Basin. It indicates that those two pathways do not change strictly with increasing buried depth. CO2 reduction is important near the surface (between 50 m and 160 m), and at the mesozone (between 400 and 1650 m). While acetate fermentation is the primary pathway at two zones, from 160 to 400 m and from 1650 to 1700 m. D 13C of methane generated in those two acetate fermentation zones varies greatly, owing to different sediment circumstances. At the second zone (160-400 m), d 13C1 ranges from -65‰ to -30‰ (PDB), because the main deposit is mudstone and makes the circumstance confined. At the fourth zone of the well bottom (1650-1700 m), d 13C1 is lighter than -65‰ (PDB). Because the deposit is mainly composed of siltstone, it well connects with outer fertile groundwater and abundant nutrition has supplied into this open system. The high concentration of acetate is a forceful proof. D 13C of methane would not turn heavier during fermentation, owing to enough nutrition supply. In spite of multi-occurrence of acetate fermentation, the commercial gas accumulation is dominated by methane of CO2-reduction pathway. A certain content of alkene gases in the biogenic gases suggests that methanogensis is still active at present.

  10. Longitudinal distributions of two formation pathways of biogenic gases in continental deposits: A case study from Sebei 1 gas field in the Qaidam Basin, western China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The distribution of two formation pathways of biogenic methane, acetate fermentation and reduction of CO2, has been extensively studied. In general, CO2 reduction is the dominate pathway in marine envi- ronment where acetate is relatively depleted because of SRB consuming. While in terrestrial freshwater or brackish environment, acetate fermentation is initially significant, but decreases with increasing buried depth. In this paper, character of biogenic gases is profiled in the XS3-4 well of the Sebei 1 gas field in the Sanhu depression, Qaidam Basin. It indicates that those two pathways do not change strictly with increasing buried depth. CO2 reduction is important near the surface (between 50 m and 160 m), and at the mesozone (between 400 and 1650 m). While acetate fermentation is the primary pathway at two zones, from 160 to 400 m and from 1650 to 1700 m. δ 13C of methane generated in those two acetate fermentation zones varies greatly, owing to different sediment circumstances. At the sec- ond zone (160-400 m), δ 13C1 ranges from ?65‰ to ?30‰ (PDB), because the main deposit is mudstone and makes the circumstance confined. At the fourth zone of the well bottom (1650-1700 m), δ 13C1 is lighter than ?65‰ (PDB). Because the deposit is mainly composed of siltstone, it well connects with outer fertile groundwater and abundant nutrition has supplied into this open system. The high con- centration of acetate is a forceful proof. δ 13C of methane would not turn heavier during fermentation, owing to enough nutrition supply. In spite of multi-occurrence of acetate fermentation, the commercial gas accumulation is dominated by methane of CO2-reduction pathway. A certain content of alkene gases in the biogenic gases suggests that methanogensis is still active at present.

  11. Wind as the primary driver of erosion in the Qaidam Basin, China

    Science.gov (United States)

    Rohrmann, Alexander; Heermance, Richard; Kapp, Paul; Cai, Fulong

    2013-07-01

    Deserts are a major source of loess and may undergo substantial wind-erosion as evidenced by yardang fields, deflation pans, and wind-scoured bedrock landscapes. However, there are few quantitative estimates of bedrock removal by wind abrasion and deflation. Here, we report wind-erosion rates in the western Qaidam Basin in central China based on measurements of cosmogenic 10Be in exhumed Miocene sedimentary bedrock. Sedimentary bedrock erosion rates range from 0.05 to 0.4 mm/yr, although the majority of measurements cluster at 0.125±0.05 mm/yr. These results, combined with previous work, indicate that strong winds, hyper-aridity, exposure of friable Neogene strata, and ongoing rock deformation and uplift in the western Qaidam Basin have created an environment where wind, instead of water, is the dominant agent of erosion and sediment transport. Its geographic location (upwind) combined with volumetric estimates suggest that the Qaidam Basin is a major source (up to 50%) of dust to the Chinese Loess Plateau to the east. The cosmogenically derived wind erosion rates are within the range of erosion rates determined from glacial and fluvial dominated landscapes worldwide, exemplifying the effectiveness of wind to erode and transport significant quantities of bedrock.

  12. Denan Depression controlled by northeast-directed Olongbulak Thrust Zone in northeastern Qaidam basin: Implications for growth of northern Tibetan Plateau

    Science.gov (United States)

    Yu, Xiangjiang; Guo, Zhaojie; Zhang, Qiquan; Cheng, Xiang; Du, Wei; Wang, Zhendong; Bian, Qing

    2017-10-01

    The Denan Depression is a unique depression in the northeastern Qaidam basin, with a maximum Cenozoic sedimentary thickness of 5 km. Detailed field work, interpretation of seismic profiles and analyzation of well data were conducted to define the Cenozoic tectonic evolution of the northeastern Qaidam basin. All geological evidences indicate that the Denan Depression is controlled by the northeast-directed Olongbulak Thrust at its southern boundary. The Denan Depression grew in concert with the development of the northeast-directed Olongbulak Thrust at least since it began to accept the Xiaganchaigou Formation, supporting the early Cenozoic growth of the northern Tibetan Plateau. Surface and subsurface data both point to enhanced tectonic activity since the Quaternary in the northeastern Qaidam basin, leading to a more individual Denan Depression relative to the main Qaidam basin. The northern boundary of the Denan Depression is a passive boundary, and no foreland developed at the northern slope of the Denan Depression.

  13. Paleoenvironmental reconstruction of the late Cenozoic Qaidam Basin, China

    Science.gov (United States)

    Zhang, C.; Wang, Y.; Li, Q.; Wang, X.; Deng, T.; Tseng, Z. J.; Takeuchi, G.; Xie, G.; Xu, Y.

    2011-12-01

    Reconstruction of paleoenvironments in the Tibetan region is important to understanding the linkage between tectonic force and climate change. Here we report new isotope data from the Qaidam Basin, China, which is located on the northeastern Tibetan Plateau, including stable C and O isotope analyses of a wide variety of late Cenozoic mammalian tooth enamel samples (including deer, giraffe, horse, rhino, and elephant), and O isotope compositions of phosphate (δ18Op) in fish bone samples. Mammalian tooth enamel δ13C values, when combined with fossil assemblage and other geological evidence, indicate that the Qaidam Basin was warmer and more humid during the late Miocene and early Pliocene, and that there was lush C3 vegetation with significant C4 components at that time, although the C4 plants were not consistently utilized. In contrast, the modern Qaidam Basin is dominated by C3 plants. Fish bone δ18Op values showed statistically significant enrichment from the Tuxi-Shengou-Naoge interval (late Miocene) to the Yahu interval (early Pliocene) and from the Yahu interval to the present day. This most likely reflects increases in the δ18O of lake water over time, as a result of increased aridification of the Qaidam Basin. Assuming that mammals drank exclusively from the lake, temperatures were calculated from average δ18Op values and average δ18Ow derived from large mammal tooth enamel δ18O. Temperatures were also estimated from δ18Op and δ18Ow estimated from co-ocurring large mammal tooth enamel δ18O. The temperature estimates were all lower than the average temperature of the modern Qinghai Lake surface water during the summer, and mostly too low to be reasonable, indicating that the fish and the large mammals were not in equilibrium with the same water. Assuming the relationship between salinity and δ18Ow observed for the modern Qinghai Lake and its surrounding lakes and ponds applied in the past, we calculated the paleosalinities of lake waters to be ~0 to

  14. Cenozoic uplift of the Tibetan Plateau: Evidence from the tectonic–sedimentary evolution of the western Qaidam Basin

    Directory of Open Access Journals (Sweden)

    Yadong Wang

    2012-03-01

    Full Text Available Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau. However, controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift. Geology has recorded this uplift well in the Qaidam Basin. This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments, faults growth index, sedimentary facies variations, and the migration of the depositional depressions. The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal. Tectonic movements controlled deposition in various depressions, and the depressions gradually shifted southeastward. In addition, the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into (a the southern fault terrace zone, (b a central Yingxiongling orogenic belt, and (c the northern fold-thrust belt; divided by the XI fault (Youshi fault and Youbei fault, respectively. The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India–Asia plate collision. Further, the Basin experienced two phases of intensive tectonic deformation. The first phase occurred during the Middle Eocene–Early Miocene (Xia Ganchaigou Fm. and Shang Ganchaigou Fm., 43.8–22 Ma, and peaked in the Early Oligocene (Upper Xia Ganchaigou Fm., 31.5 Ma. The second phase occurred between the Middle Miocene and the Present (Shang Youshashan Fm. and Qigequan Fm., 14.9–0 Ma, and was stronger than the first phase. The tectonic–sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan

  15. Application of Integrated Geophysical technology and Its Effects in the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    HaoHongjian; WangCaifu; LiuYunxiang; WeiYan; LinCunguo

    2003-01-01

    Experience gained in many years proved that oil explorations were very difficult to complete with seismic methods only in seismic-unfeasible areas. The expected results in these places could only be obtained with the integrated geophysical surveys, the combination of gravity, electric, magnetic,geochemistry and seismic methods. The high-precision gravity,magnetic and electric techniques used in seismic-unfeasible areas in Qaidam Basin had achieved many astonishing results,which demonstrated a feasible way for oil exploration in Qaidam Basin and offered a basis for data interpretation in complex areas where seismic data was not able to acquire.

  16. Organic geochemistry and petroleum geology, tectonics and basin analysis of southern Tarim and northern Qaidam basins, northwest China

    Science.gov (United States)

    Hanson, Andrew Dean

    Organic geochemistry of oils from the Tarim basin, NW China, distinguish at least seven genetic groups of oils. The largest group are derived from Middle-Upper Ordovician anoxic slope-facies marls coincident with the margins of structural uplifts. Other groups include non-marine derived oils in the Luntai uplift, from southwest Tarim, in the Kuqa depression, and west of the Bachu uplift. A seep sample from west of Kashi clusters with Luntai oils. These results suggest that numerous source-rock horizons occur, but they are really restricted. Organic geochemistry of oils from northern Qaidam defines a family of hypersaline, anoxic lacustrine derived oils. Cenozoic outcrop samples from northern Qaidam are too organic lean to be of source quality, but dark laminated upper Oligocene mudstones from the Shi 28 well are of fair to good quality. Biomarkers provide a good correlation between the oils and the core samples. Organic matter is from algae and bacteria and lacks terrestrial material. Hydrocarbons are contained in upper Oligocene, Miocene, and Pliocene reservoirs. Eight oils are from NW Qaidam, but one sample comes from NE Qaidam, an area previously believed to only produce oils derived from Jurassic source rocks. Thus an unidentified Cenozoic source rock occurs in NE Qaidam. Thermal modeling indicates generation occurred in northwestern Qaidam within the last 3 million years, agreeing with observed low maturity biomarker parameters. Cenozoic stratigraphy in northern Qaidam and southern Tarim basins record the tectonic history of the surrounding structural/topographic elements. Paleocurrents record flow away from adjacent ranges from the Miocene to the present. Provenance data tie sediments to adjacent structural elements. Petrography indicates increasingly immature sandstones in Miocene and younger sediments relative to pre-Miocene samples. Apatite fission-track results from southeastern Tarim yield a cooling age of 17 +/- 1 Ma indicative of unroofing since at

  17. Water resources optimization and eco-environmental protection in Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to realize sustainable development of the arid area of Northwest China, rational water resources exploitation and optimization are primary prerequisites. Based on the essential principle of sustainable development, this paper puts forward a general idea on water resources optimization and eco-environmental protection in Qaidam Basin, and identifies the competitive multiple targets of water resources optimization. By some qualitative methods such as Input-output Model & AHP Model and some quantitative methods such as System Dynamics Model & Produce Function Model, some standard plans of water resources optimization come into being. According to the Multiple Targets Decision by the Closest Value Model, the best plan of water resources optimization, eco-environmental protection and sustainable development in Qaidam Basin is finally decided.

  18. Analysis on structural control of coal distribution in the northern Qaidam Basin, NW China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.J.; Wang, T.; Zhan, W.F. [Qinghai Bureau of Coal Geology, Xining (China)

    2008-06-15

    The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal-controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal-controlling structural styles being mainly the thrust-fold and thrust-monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin.

  19. High genetic diversity and novelty in eukaryotic plankton assemblages inhabiting saline lakes in the Qaidam basin.

    Science.gov (United States)

    Wang, Jiali; Wang, Fang; Chu, Limin; Wang, Hao; Zhong, Zhiping; Liu, Zhipei; Gao, Jianyong; Duan, Hairong

    2014-01-01

    Saline lakes are intriguing ecosystems harboring extremely productive microbial communities in spite of their extreme environmental conditions. We performed a comprehensive analysis of the genetic diversity (18S rRNA gene) of the planktonic microbial eukaryotes (nano- and picoeukaryotes) in six different inland saline lakes located in the Qaidam Basin. The novelty level are high, with about 11.23% of the whole dataset showing 18S rRNA gene sequence reads obtained in investigated mesosaline lakes is closely related to Holozoa group (48.13%), whereas Stramenopiles (26.65%) and Alveolates (10.84%) are the next most common groups. Hypersaline lakes in the Qaidam Basin are also dominated by Holozoa group, accounting for 26.65% of the total number of sequence reads. Notably, Chlorophyta group are only found in high abundance in Lake Gasikule (28.00%), whereas less represented in other hypersaline lakes such as Gahai (0.50%) and Xiaochaidan (1.15%). Further analysis show that the compositions of planktonic eukaryotic assemblages are also most variable between different sampling sites in the same lake. Out of the parameters, four show significant correlation to this CCA: altitude, calcium, sodium and potassium concentrations. Overall, this study shows important gaps in the current knowledge about planktonic microbial eukaryotes inhabiting Qaidam Basin (hyper) saline water bodies. The identified diversity and novelty patterns among eukaryotic plankton assemblages in saline lake are of great importance for understanding and interpreting their ecology and evolution.

  20. Analysis on Structural Control of Coal Distribution in the Northern Qaidam Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    LIU Tianji; WANG Tong; ZHAN Wenfeng

    2008-01-01

    The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal-controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal-controlling structural styles being mainly the thrust-fold and thrust-monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin.

  1. Direction and Potential of Exploration for Natural Gas in Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Qaidam Basin is a large Meso-Cenozoic interior basin, which is surrounded by Qilianshan Mountains,Altun Mountains, and Kunlun Mountains, and with its geographical area, area of sedimentary rock, and maximal sedimentary thickness being 250 thousand km2, 121 thousand km2, and 17.2 thousand meters respectively. The natural gas resources is sufficiently abundant in the basin.It is estimated that the total oil and gas resources is 4.65 billion tons at present, of which natural gas resources is 2500 billion m3.

  2. The special sealing mechanism of caprock for Quaternary biogenetic gas in Sanhu area,Qaidam Basin,China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Quaternary biogenetic gas reservoirs in the east of Qaidam Basin have many characteristics such as late forming time,shallow burial depth,low diagenetic grade,high porosity and high permeability and so on.It cannot be considered as caprock according to the traditional evaluation criterion.However, the large scale and high efficient biogenetic gas reservoirs of the Qaidam Basin are really formed under these kinds of caprocks,so it does have some specialty in its sealing mechanism.Aiming at the special sealing mechanism,some simulating experiments have been done.The research results show that the sealing ability of biogenetic gas caprock is related with water saturation,the caprock that is saturated with salt water can effectively block seepage and diffusion.Furthermore,the multiple reservoir-caprock groups have accumulated sealing effect,causing the formation of big gas fields.The evaluation method with traditional caprock parameters cannot be adopted in evaluating the study area.

  3. Groundwater circulation and hydrogeochemical evolution in Nomhon of Qaidam Basin, northwest China

    Indian Academy of Sciences (India)

    Yong Xiao; Jingli Shao; Yali Cui; Ge Zhang; Qiulan Zhang

    2017-03-01

    In this study, analysis of hydrogeological conditions, as well as hydrochemistry and isotopic tools were used to get an insight into the processes controlling mineralization, recharge conditions, and flow pattern of groundwater in a typical arid alluvial-lacustrine plain in Qaidam Basin, northwest China. Analysisof the dissolved constituents reveals that groundwater evolves from fresh water (TDS=300–1000 mg/l) to saline water (TDS ≥5000 mg/l) along the flow paths, with the water type transiting from HCO ₃•Cl– Na•Mg to HCO ₃•Cl–Na, and eventually to Cl–Na. Groundwater chemical evolution is mainly controlled by water–rock interaction and the evaporation–crystallization process. Deuterium and oxygen-18 isotopes in groundwater samples indicate that the recharge of groundwater is happened by meteoric water andglacier melt-water in the Kunlun Mountains, and in three different recharge conditions. Groundwater ages, estimated by the radiogenic (³H and ¹⁴C) isotope data, range from present to Holocene (~28ka). Based on groundwater residence time, hydrogeochemical characteristics, field investigation, and geological structure distribution, a conceptual groundwater flow pattern affected by uplift structure is proposed, indicating that shallow phreatic water is blocked by the uplift structure and the flow directionis turned to the northwest, while high pressure artesian water is formed in the confined aquifers at the axis of the uplift structure.

  4. High genetic diversity and novelty in eukaryotic plankton assemblages inhabiting saline lakes in the Qaidam basin.

    Directory of Open Access Journals (Sweden)

    Jiali Wang

    Full Text Available Saline lakes are intriguing ecosystems harboring extremely productive microbial communities in spite of their extreme environmental conditions. We performed a comprehensive analysis of the genetic diversity (18S rRNA gene of the planktonic microbial eukaryotes (nano- and picoeukaryotes in six different inland saline lakes located in the Qaidam Basin. The novelty level are high, with about 11.23% of the whole dataset showing <90% identity to any previously reported sequence in GenBank. At least 4 operational taxonomic units (OTUs in mesosaline lakes, while up to eighteen OTUs in hypersaline lakes show very low CCM and CEM scores, indicating that these sequences are highly distantly related to any existing sequence. Most of the 18S rRNA gene sequence reads obtained in investigated mesosaline lakes is closely related to Holozoa group (48.13%, whereas Stramenopiles (26.65% and Alveolates (10.84% are the next most common groups. Hypersaline lakes in the Qaidam Basin are also dominated by Holozoa group, accounting for 26.65% of the total number of sequence reads. Notably, Chlorophyta group are only found in high abundance in Lake Gasikule (28.00%, whereas less represented in other hypersaline lakes such as Gahai (0.50% and Xiaochaidan (1.15%. Further analysis show that the compositions of planktonic eukaryotic assemblages are also most variable between different sampling sites in the same lake. Out of the parameters, four show significant correlation to this CCA: altitude, calcium, sodium and potassium concentrations. Overall, this study shows important gaps in the current knowledge about planktonic microbial eukaryotes inhabiting Qaidam Basin (hyper saline water bodies. The identified diversity and novelty patterns among eukaryotic plankton assemblages in saline lake are of great importance for understanding and interpreting their ecology and evolution.

  5. A large Middle Pleistocene freshwater to oligohaline lake in the contemporary hyperarid Qaidam Basin (China)

    Institute of Scientific and Technical Information of China (English)

    Steffen Mischke; Ulrike Herzschuh; Naida Sun; Zizhen Qiao; Zhencheng Sun

    2006-01-01

    @@ The Qaidam Basin (NW China) at the northern margin of the Tibetan Plateau is one of the driest places on Earth with mean annual precipitation not exceeding 25mm in the western central part. Flat salt plains and wind-shaped hills characterise the bare ground over thousands of square kilometres. In contrast to presentday conditions, remnants of ancient shorelines in high positions identified by Chen and Bowler (1986) and Hovermann and Süssenberger (1986) about 20 years ago herald of a former large lake but were not investigated further till now.

  6. Late Cenozoic continuous aridification in the western Qaidam Basin: evidence from sporopollen records

    Directory of Open Access Journals (Sweden)

    Y. F. Miao

    2013-03-01

    Full Text Available Cenozoic climate changes in inner Asia provide a basis for understanding linkages between global cooling, the Tibetan Plateau uplift, and possibly the development of the East Asian monsoon. Based on the compiled palynological results from the western Qaidam Basin, this study reconstructed an 18 Ma record of changing vegetation and paleoclimates since the middle Miocene. Thermophilic taxa percentages were highest between 18 and 14 Ma and decreased after 14 Ma, corresponding closely with the Middle Miocene Climatic Optimum (MMCO between 18 and 14 Ma and the following global climatic cooling. After 3.6 Ma, the thermophilic taxa percentages further decreased, showing the inevitable relations with the ice-sheets enlargement in the North Hemisphere. During the same period of time, the increase in xerophytic taxa percentages and decrease in conifers percentages imply aridification in both the basin and surrounding mountains since 18 Ma. These results indicate that global cooling mainly controlled the climate change from a relative warm-wet stage to a cold-dry stage during the late Cenozoic at the western Qaidam Basin, and that the Tibetan Plateau uplift also contributed in contrast to the East Asian summer monsoon.

  7. Characteristics and genesis of clay minerals in the northern margin of the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    Wang Linlin; Jiang Bo; Peng Dehua; Yin Chengming; Zeng Chunlin

    2011-01-01

    In order to develop appropriate reservoir protection measures in the northern margin of the Qaidam Basin and improve its oil and gas recovery efficiency, characteristics of clay minerals from eleven clay rock samples from the northern margin of the Qaidam Basin were investigated using X-ray diffraction analysis, the Scanning Electron Microscope (SEM) and energy spectrum analysis. Clay mineral composition and distribution characteristics of the main hydrocarbon reservoirs, I.e., from the Jurassic and Paleogene-Neogene, were explored. We analyzed the main factors which affected these attributes. The results show that the major clay minerals in the northern margin are chlorite, kaolinite, illite, smectite and illite/smectite inter-stratified minerals, Illite is the most widely spread clay mineral in this area.Chlorite is mainly found in the entire Neogene and in shallow horizons of the Paleogene. Smectite is enriched in the shallow Paleogene-Neogene. There are large amounts of kaolinite and illite/smectite inter-stratified minerals in the Jurassic. The major factors affecting the different development of clay minerals in the region are properties of parent rocks, paleoclimate and paleowater media conditions,diagenesis transformation, tectonic and terrain conditions.

  8. Carbon isotope characteristics, origin and distribution of the natural gases from the Tertiary salty lacustrine facies in the West Depression Region in the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    张晓宝; 胡勇; 马立元; 孟自芳; 段毅; 周世新; 彭德华

    2003-01-01

    The Tertiary in the West Depression Region of the Qaidam Basin has the typical inland salty lacustrine deposits in China. 34 natural gas samples were collected from 13 oil fields in the West Depression Region in the basin, the chemical compositions and carbon isotopes of methane, ethane, propane, and butane were measured. According to the carbon isotope characteristics of natural gases in combination with geochemical characteristics of the source rocks and crude oils, the natural gases can be divided into sapropelic associated gas, mixed organic matter-derived associated gas, coal-derived gas and mixed gas. The carbon isotope characteristics, origin and distribution of the natural gases are considered to be related with the types and distribution of organic inputs in lake environments with different salinities. The lake salinity can regionally forecast the distribution of the different genetic types of natural gas. Compared with the different genetic types of natural gas from other Chinese basins, the carbon isotopes of the heavy hydrocarbons of the natural gas from the Tertiary salt lacustrine facies in the Qaidam Basin are extremely heavier. Therefore, this should be considered when natural gases are genetically classified in the basin.

  9. Diets and environments of late Cenozoic mammals in the Qaidam Basin, Tibetan Plateau: Evidence from stable isotopes

    Science.gov (United States)

    Zhang, Chunfu; Wang, Yang; Li, Qiang; Wang, Xiaoming; Deng, Tao; Tseng, Zhijie J.; Takeuchi, Gary T.; Xie, Gangpu; Xu, Yingfeng

    2012-06-01

    The timing history and driving mechanisms of C4 expansion and Tibetan uplift are hotly debated issues. Paleoenvironmental evidence from within the Tibetan Plateau is essential to help resolve these issues. Here we report results of stable C and O isotope analyses of tooth enamel samples from a variety of late Cenozoic mammals, including deer, giraffe, horse, rhino, and elephant, from the Qaidam Basin in the northeastern Tibetan Plateau. The enamel-δ13C values are <-8‰ for modern samples and ≤-7‰ for fossils, except for one late Miocene rhino (CD0722, with δ13C values up to -4.1‰). If the Qaidam Basin was as arid as today in the Mio-Pliocene, these data would indicate that the majority of the animals had C3 diets and only a few individuals (besides the exceptional rhino CD0722) may have consumed some C4 plants. Based on geological evidence, however, the Qaidam Basin was probably warmer and more humid during the late Miocene and early Pliocene than today. Thus, these δ13C values likely indicate that many individuals had significant dietary intakes of C4 plants, and the Qaidam Basin had more C4 plants in the late Miocene and early Pliocene than today. Moreover, the Qaidam Basin likely had much denser vegetation at those times in order to support such large mammals as rhinos and elephants. While the δ18O values did not increase monotonously with time, the range of variation seems to have increased considerably since the early Pliocene, indicating increased aridification in the basin. The mean δ18O values of large mammals and those reconstructed for local meteoric waters display a significant negative shift in the late Miocene, consistent with the marine δ18O record which shows a cooling trend in the same period. Taken together, the isotope data suggest a warmer, wetter, and perhaps lower Qaidam Basin during the late Miocene and early Pliocene. Increased aridification after the early Pliocene is likely due to a combined effect of regional tectonism, which

  10. Paleogene and Early Neogene Lacustrine Reefs in the Western Qaidam Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jianhua; WEN Zhifeng; GUO Zeqing; WANG Haiqiao; GAO Jianbo

    2004-01-01

    Typical reefs in the Paleogene and early Neogene strata of the Qaidam Basin, Tibetan Plateau, China, reveal their internal structures and sedimentation environments and consist mainly of algal reef, stromatolite reef and thrombolite reef with distinct reef structures, fore-reef, back-reef and reef-plateau. The fore-reef is characterized by a combination of pinnacle reef, thrombolite and algal reef. The back reef is composed of stromatolite reef and algal reef. The pinnacle reefs (micro-atoll), most of which are several tens of centimeters in diameter (whereas some exceptionally big ones are over 200 cm in diameter), and several tens of centimeter to 2 m in height, are situated on the far front-edge of the reef; the pinnacle reef is also often of recumbent form with a gravel-filled circular hole in the center. The algal reef is in the form of dome and irregular beds, and filled with algal detritus, ostracodes, spirorbis fossils, ooid and terrigenous debris, and worm traces;cavities and scour marks are often developed. The algal reef is gray commonly when fresh and weathers to a brown color.The lacustrine thrombolite in the Qaidam Basin is light gray or deep gray when fresh, white-gray or brown when weathered, dense and homogeneous with abundant pores filled by oil and bitumen. Observed under the microscope, the thrombolite consists mainly of brown or brown-black clots with a little algal debris, ooid, pellet, ostracodes, spirorbis fossils and terrigenous debris, in some cases, terrigenous debris, even gravel, is abundant. Many features of the thrombolite suggest that it is formed in a high-energy environment. The stromatolite reefs developed on the lacustrine algal reef in the Qaldam Basin are very complex whether in shape or in internal structure. The simplest ones form laminated layers and the most complex ones have intensely branching structures. The size is also variable.

  11. Late Cenozoic pollen records and paleoclimate in the western Qaidam Basin, Northern Tibetan Plateau

    Science.gov (United States)

    Miao, Y.

    2013-12-01

    Y. F. Miao1, X. M. Fang2*, F. L. Wu2, M. T. Cai2, C. H. Song3, Q. Q. Meng3 1 Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Institute, Chinese Academy of Sciences, Lanzhou, 730000, China 2 Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China 3 School of Earth Science, Lanzhou University, Lanzhou, 730000, China * Corresponding author, E-mail address: fangxm@itpcas.ac.cn (X.M. Fang). Abstract: Cenozoic climate changes in inner Asia provide a basis for understanding linkages between global cooling, the Tibetan Plateau uplift, and possibly the development of the East Asian monsoon. Based on a compilation of palynological results from the western Qaidam Basin, this study reconstructed a 15 million years (Ma) record of changing vegetation and paleoclimates spanning the middle Miocene to present (comprising two series: ~18-5 Ma and ~3.1-0 Ma, respectively). The thermophilic percentages were highest between 18 and 14 Ma, and decreased after 14 Ma, closely corresponding to the Middle Miocene Climatic Optimum (MMCO) between 18 and 14 Ma and the following global climatic cooling between 14 and 5 Ma. At the same time, decreases in the xerophytic and coniferous taxa percentages, and the increasing logarithmic ratio of non-arboreal pollen to arboreal pollen (ln (NAP/AP)), reveal the continuous aridification across both the basin and surrounding mountains. Between ~3.1-0 Ma, the percentages of the thermophilic, xerophytic and coniferous pollen as well as the ln (NAP/AP) imply further cooling and drying in this region since 3.1 Ma. We argue that these vegetation and climate patterns during the late Cenozoic western Qaidam Basin are primarily a result of the global cooling, with the Tibetan Plateau uplift and East Asian summer monsoon having contributions of lesser importance.

  12. Cenozoic sediment flux in the Qaidam Basin, northern Tibetan Plateau, and implications with regional tectonics and climate

    Science.gov (United States)

    Bao, Jing; Wang, Yadong; Song, Chunhui; Feng, Ying; Hu, Chunhua; Zhong, Sirui; Yang, Jiwei

    2017-08-01

    As the largest Mesozoic-Cenozoic terrestrial intermountain basin in the northern Tibetan Plateau, the Qaidam Basin is an ideal basin to examine the influences of regional tectonics and climate on sediment flux. Research conducted over the last two decades has provided abundant information about paleoclimatology and tectonic histories. In this study, we used the restoration of seven balanced cross-sections and compiled thickness data of ten outcrop sections and four boreholes to reconstruct the basin boundaries, develop isopach maps, and calculate the sediment flux in the Qaidam Basin. Our results show that the sediment flux in the Qaidam Basin increased gradually between 53.5 and 35.5 Ma, decreased to its lowest value from 35.5 to 22 Ma, increased between 22 and 2.5 Ma, and then increased dramatically after 2.5 Ma. By comparing the changes in the sediment flux with our reconstructed shortening rate in the Qaidam Basin, and the records of regional tectonic events and regional and global climate changes, we suggest that the gradual increase in the sediment flux from 53.5 to 40.5 Ma was controlled by both the tectonic uplift of the Tibetan Plateau and the relatively warm and humid climate, and that the high sediment flux from 40.5 to 35.5 Ma was mainly controlled by tectonics. The low sediment flux from 35.5 to 22 Ma was a response to the relatively cold and arid climate in a stable tectonic setting. The relatively high sediment flux between 22 and 15.3 Ma was related to tectonic activity and the warm and humid climate. The intense tectonic uplift of the northern Tibetan Plateau and the frequent climate oscillations after 15.3 Ma, particularly the glacial-interglacial cycles after 2.5 Ma, caused the high sediment flux after 15.3 Ma and the dramatic increase after 2.5 Ma, respectively.

  13. Sedimentation Geochemistry and Environmental Changes during the Late Pleistocene of Paleolake Qarhan in the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    Chang Fengqin; Yang Lunqing; Zhang Hucai; Chen Yue; Yang Mingsheng; Niu Jie; Fan Hongfang; Lei Guoliang; Zhang Wenxiang; Lei Yanbin

    2008-01-01

    On the basis of the analyses of TOC, CaCO3, δ13Corg, δ18O, and δ13C of the shell bar section in the Qaidam basin, and compared with grain size data, the environmental change history of the high water level of paleolake Qarhan was reconstructed and it could be divided into five stages. From 39.7 to 35.8 kaBP was the development period of high paleolake level. From 35.8 to 33.6 kaBP and 33.6 to 27.2 kaBP, TOC and CaCO3 contents and δ18O values were high, whereas, δ13Corg values and median size content were low, reflecting a warm-humid climate and high lake level. During 27.2-22.3 kaBP and 22.3-17.5 kaBP, both temperature and the lake level were lower than those in the previous stages, but the climate was still warmer and more humid than that of today. The lake level decreased between 32.4 and 32.2 kaBP, 30.4 and 29.8 kaBP, and 28.4 and 27.2 kaBP. Generally, the climate was warm and humid in Qaidam basin and the high lake level sustained between 39.7 and 17.5 kaBP. The lake retreated abruptly at 17.5 kaBP, with a very strong increase in evaporation, which resulted in salt formation and the extinction of Corbicula.

  14. Two-stage evolution of the Cenozoic Kunbei fault system and its control of deposition in the SW Qaidam Basin, China

    Science.gov (United States)

    Zhu, Wen; Wu, Chaodong; Wang, Jialin; Fang, Ya'nan; Wang, Chuanwu; Chen, Qilin; Liu, Huaqing

    2017-09-01

    The structural relationship between the Qaidam Basin and Qimen Tagh-Eastern Kunlun Range holds important implications for evaluating the formation mechanism of the Tibetan Plateau. Various models have been proposed to reveal the structural relationship, although controversies remain. To address these issues, we analysed the seismic and lithologic data of the Kunbei fault system (i.e. the Kunbei, Arlar and Hongliuquan faults), which lies to the north of the Qimen Tagh-Eastern Kunlun Range within the SW Qaidam Basin. Based on the regional geological framework and our kinematic analyses, we propose that the Cenozoic tectonic evolution of the Kunbei fault system can be divided into two stages. From the Early Eocene to the Middle Miocene, the system was characterized by left-lateral strike-slip faults and weak south-dipping thrust faults based on the flower structure in the seismic section, which is an apparent strike-slip deformation that was identified in the -1510-ms time slice and the root-mean-square amplitude attribute slice. This strike-slip motion was generated by the uplift of the Tibetan Plateau caused by the onset of the Indian-Eurasian collision. Since the Middle Miocene, the Kunbei fault system has undergone intense south-dipping thrusting, and a nearly 2.2-km uplift has been observed in the hanging wall in the Arlar fault. The south-dipping thrusting is the far-field effect of the full collision that occurred between the Indian-Eurasian plates. The lake area in the SW Qaidam Basin has been shrinking since the Middle Miocene and presents widespread delta and fluvial deposits, which are consistent with the proposed tectonic evolution.

  15. Two-stage evolution of the Cenozoic Kunbei fault system and its control of deposition in the SW Qaidam Basin, China

    Science.gov (United States)

    Zhu, Wen; Wu, Chaodong; Wang, Jialin; Fang, Ya'nan; Wang, Chuanwu; Chen, Qilin; Liu, Huaqing

    2016-09-01

    The structural relationship between the Qaidam Basin and Qimen Tagh-Eastern Kunlun Range holds important implications for evaluating the formation mechanism of the Tibetan Plateau. Various models have been proposed to reveal the structural relationship, although controversies remain. To address these issues, we analysed the seismic and lithologic data of the Kunbei fault system (i.e. the Kunbei, Arlar and Hongliuquan faults), which lies to the north of the Qimen Tagh-Eastern Kunlun Range within the SW Qaidam Basin. Based on the regional geological framework and our kinematic analyses, we propose that the Cenozoic tectonic evolution of the Kunbei fault system can be divided into two stages. From the Early Eocene to the Middle Miocene, the system was characterized by left-lateral strike-slip faults and weak south-dipping thrust faults based on the flower structure in the seismic section, which is an apparent strike-slip deformation that was identified in the -1510-ms time slice and the root-mean-square amplitude attribute slice. This strike-slip motion was generated by the uplift of the Tibetan Plateau caused by the onset of the Indian-Eurasian collision. Since the Middle Miocene, the Kunbei fault system has undergone intense south-dipping thrusting, and a nearly 2.2-km uplift has been observed in the hanging wall in the Arlar fault. The south-dipping thrusting is the far-field effect of the full collision that occurred between the Indian-Eurasian plates. The lake area in the SW Qaidam Basin has been shrinking since the Middle Miocene and presents widespread delta and fluvial deposits, which are consistent with the proposed tectonic evolution.

  16. Oscillation of mineral compositions in Core SG-1b, western Qaidam Basin, NE Tibetan Plateau

    Science.gov (United States)

    Fang, Xiaomin; Li, Minghui; Wang, Zhengrong; Wang, Jiuyi; Li, Jiao; Liu, Xiaoming; Zan, Jinbo

    2016-09-01

    Uplift of the Tibetan Plateau since the Late Miocene has greatly affected the nature of sediments deposited in the Qaidam Basin. However, due to the scarcity of continuously dated sediment records, we know little about how minerals responded to this uplift. In order to understand this response, we here present results from the high-resolution mineral profile from a borehole (7.3–1.6 Ma) in the Basin, which shows systematic oscillations of various evaporite and clay minerals that can be linked to the variation of regional climate and tectonic history. In particular, x-ray diffraction (XRD) analyses show that carbonate minerals consist mainly of calcite and aragonite, with minor ankerite and dolomite. Evaporates consist of gypsum, celesite and halite. Clay minerals are principally Fe-Mg illite, mixed layers of illite/smectite and chlorite, with minor kaolinite and smectite. Following implications can be drawn from the oscillations of these minerals phases: (a) the paleolake was brackish with high salinity after 7.3 Ma, while an abrupt change in the chemical composition of paleolake water (e.g. Mg/Ca ratio, SO42‑ concentration, salinity) occurred at 3.3 Ma; (b) the three changes at ~6.0 Ma, 4.5–4.1 Ma and 3.3 Ma were in response to rapid erosions/uplift of the basin; (c) pore water or fluid was Fe/Mg-rich in 7.3–6.0 Ma, Mg-rich in 6.0–4.5 Ma, and K-rich in 4.1–1.6 Ma and (d) evaporation rates were high, but weaker than today’s.

  17. Branched aliphatic alkanes of shell bar section in Qarhan Lake, Qaidam Basin and their paleoclimate significance

    Institute of Scientific and Technical Information of China (English)

    ZHANG HuCai; CHANG FengQin; LI Bin; LEI GuoLiang; CHEN Yue; ZHANG WenXiang; NIU Jie; FAN HongFang; YANG MingSheng

    2007-01-01

    Biomarkers of paleolake deposits from Qarhan Salt Lake in Qaidam Basin, northwest China were systematically analyzed and the A-C series compounds of branched aliphatic alkanes with quaternary substituted carbon atom (BAQCs) were identified. The homologous distinguished three series, A-C,were identified as 5,5-diethylalkanes, 6,6-diethylalkanes and 5-butyl, 5-ethylalkanes series, and their relative abundance was A > B > C. Series A and C were characterized by odd carbon numbers, whereas series B was characterized by even carbon numbers. The high values of series A corresponded with the high values of series B and C. Therefore, it can be concluded that series A, B and C possess a similar biological origin. The abundance of series A was relatively Iow in the lower part of the section compared with that in the upper part, implying that these series originated from bacteria and/or algae more prevalent in fresh-mesohaline water, and such kinds of bacteria and/or algae are most likely to be thermophilous species. The A25/nC25 ratio differences in the section show that such branched aliphatic alkanes can be treated as one kind of environmental change proxy for paleolake evolution and may provide important information for the climate reconstruction of the Late Pleistocene.

  18. 柴达木盆地近期勘探工作思考%Consideration about Recent Oil and Gas Exploration of Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    付锁堂; 关平; 张道伟

    2012-01-01

    Qaidam basin, which is the seventh-largest petroliferous basins in China,is rich in oil and gas resources. Therefore, the basin possesses the conditions to be a large-scale oil and gas field. However, the strong Cenozoic Himalayan orogeny resulted in the complex structure of Qaidam basin. The source-reservoir-cap assemblage of the oil and gas field has been reformed intensively. And later reformations make the exploration become more difficult. For the petroleum enterprise,once faced a harsher circumstance to increase reserve and production. However,in recent years with the great support of the joint-stock company leadership, Qinghai Oilfield Company continues to emanci pate the mind. In terms of carefully and systematic analysis of the structure, deposition and petroleum geological conditions of Qaidam basin, explorationists changing the old exploration thoughts positively, and the exploration work obtains continuous breakthroughs. Two oil fields with 100 million ton reserves (Kunbei,Yingdong) and three oil fields with 50 million ton reserves (Hongliuquan,Wunan and Mabei) were sequentially discovered by Qinghai Oilfield Company. Natural gas risk exploration in deep zone of Eboliang III and Tainan reserves fields has also gains a major breakthrough progress. According to summarize the successful experience, we can sum up five guiding ide- ologies and four working principles. These ideas and principles play very important roles in making exploration work get breakthrough progress and successfully increasing reserves and production of Qaidam basin.%柴达木盆地是我国七大含油气盆地之一,油气资源丰富,具备建立大型油气田的资源基础。受新生代强烈的喜马拉雅造山运动的影响,盆地内构造十分复杂,油气田生、储、盖组合的后期改造非常严重,使得勘探难度很大,"增储上产"曾一度面临严峻的形势。但近年来青海油田公司通过解放思想,在认真系统地分析柴达木盆地构

  19. Late Eocene clay boron-derived paleosalinity in the Qaidam Basin and its implications for regional tectonics and climate

    Science.gov (United States)

    Ye, Chengcheng; Yang, Yibo; Fang, Xiaomin; Zhang, Weilin

    2016-12-01

    The Qaidam Basin, located on the northeastern Tibetan Plateau and containing Cenozoic sediments with a maximum thickness of 12,000 m, is an ideal place to study the phased uplift of the NE Tibetan Plateau and regional climate change. The estimation of the paleosalinity of sedimentary environments not only helps to evaluate the evolution of lakes in this region but offers insights into contemporaneous climate change. We present detailed geochemical and mineralogical investigations from the lacustrine interval of the Hongliugou section in the northern Qaidam Basin to reconstruct salinity fluctuations in the paleolake during the late Eocene era ( 42.0-35.5 Ma). The clay mineral assemblages mainly contain smectite, illite, chlorite, kaolinite and irregular illite/smectite mixed layers. Clay boron-derived paleosalinity estimates (equivalent boron content, Couch's paleosalimeter and B/Ga ratios) along with other proxies sensitive to salinity changes (e.g., Rb/K ratios and ostracod assemblages) collectively indicate an overall brackish sedimentary environment with a higher-salinity period at approximately 40.0-39.2 Ma. This higher-salinity period indicates a more arid environment and is probably related to global cooling. However, the global cooling in late Eocene cannot explain the overall stable long-term salinity pattern, implying that other factors exist. We propose that the migration of the Yiliping depression depocenter in the northern Qaidam and increased orographic rainfall induced by late Eocene tectonic activity at the northern margin of the basin might have partly offset the increase in salinity driven by global cooling.

  20. Application of teleseismic tomography to the study of shallow structure beneath Shizigou in the western Qaidam basin

    Institute of Scientific and Technical Information of China (English)

    Xiaoming Xu; Yinsheng Ma; Danian Shi; Xiaofeng Wang; Chengming Yin

    2009-01-01

    Teleseismic body wave traveltime tomography is used to inverse the three-dimensional seismic velocity structure beneath Shizigou in the western Qaidam basin. The travel time are picked from the continuous observation data on a small seismic array of stations deployed during 2004-2007. The tomographic results obtained indicate that a NW-trending low velocity anomaly just beneath the target region insert northeastwards with a high dip angle, to the north, northeast and east of the low velocity anomaly, some high-velocity anomalies distribute with the same strike and coverage as those of Shizigou anticline.

  1. Geochemical fractionation of rare earth elements in lacustrine deposits from Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    ZHANG HuCai; ZHANG WenXiang; CHANG FengQin; YANG LunQing; LEI GuoLiang; YANG MingSheng; PU Yang; LEI YangBin

    2009-01-01

    Based on the concentration and distribution pattern analysis of the rare earth elements (REEs) at the Shell Bar section from Qaidam Basin,we studied the geochemical fractionations of REE in paleolake deposits and their paleo-environmental significance.Our results show that the REE concentration in AS (acid soluble) and AR (acid residual) fractions are 20.9 μg/g and 95.4 μg/g (except element Y) individually,showing a strong REE differentiation between AS and AR fractions.However,the two types of fractions (AS & AR) have similar REE distribution patterns,which are slightly rich in light earth rare elements (LREEs),with slightly right-tilting and negative Eu anomaly.The LREE of AR is richer than that of AS.There were no significant correlations between the REE in AS,AR and other proxies.It indicated that the lacustrine deposition had different material sources and experienced varying geochemical procedures.Correlation analysis between the REE and the content of fine grain-size (<4 μm) of the sediments,Rb/Sr ratio and Mn concentration showed high correlation coefficients.Our results demonstrated that the REE in acid soluble and residual fractions bear different environmental significances,which are strongly dependent on local environment.The REE of acid soluble fraction is closely related to the paleoclimatic changes in the lake catchment and the evolutionary processes of lake itself.Our results suggest that δCe and (La/Yb)_n could be used as proxies of the reduction-oxidation conditions and furthermore the temperature change and the lake level fluctuations.Using these proxies,we reconstructed the paleoclimate and water level fluctuation history during the high lake level period lasting between 43.5 and 22.4 cal.ka BP.

  2. Geochemical fractionation of rare earth elements in lacustrine deposits from Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the concentration and distribution pattern analysis of the rare earth elements (REEs) at the Shell Bar section from Qaidam Basin, we studied the geochemical fractionations of REE in paleolake deposits and their paleo-environmental significance. Our results show that the REE concentration in AS (acid soluble) and AR (acid residual) fractions are 20.9 μg/g and 95.4 μg/g (except element Y) individually, showing a strong REE differentiation between AS and AR fractions. However, the two types of fractions (AS & AR) have similar REE distribution patterns, which are slightly rich in light earth rare elements (LREEs), with slightly right-tilting and negative Eu anomaly. The LREE of AR is richer than that of AS. There were no significant correlations between the REE in AS, AR and other proxies. It indicated that the lacustrine deposition had different material sources and experienced varying geochemical procedures. Correlation analysis between the REE and the content of fine grain-size (<4 μm) of the sediments, Rb/Sr ratio and Mn concentration showed high correlation coefficients. Our results demonstrated that the REE in acid soluble and residual fractions bear different environmental significances, which are strongly dependent on local environment. The REE of acid soluble fraction is closely related to the paleoclimatic changes in the lake catchment and the evolutionary processes of lake itself. Our results suggest that δCe and (La/Yb)n could be used as proxies of the reduction-oxidation conditions and furthermore the temperature change and the lake level fluctuations. Using these proxies, we reconstructed the paleoclimate and water level fluctuation history during the high lake level period lasting between 43.5 and 22.4 cal. ka BP.

  3. Lower crustal relaxation beneath the Tibetan Plateau and Qaidam Basin following the 2001 Kokoxili earthquake

    Science.gov (United States)

    Ryder, I.; Burgmann, R.; Pollitz, F.

    2011-01-01

    In 2001 November a magnitude 7.8 earthquake ruptured a 400 km long portion of the Kunlun fault, northeastern Tibet. In this study, we analyse over five years of post-seismic geodetic data and interpret the observed surface deformation in terms of stress relaxation in the thick Tibetan lower crust. We model GPS time-series (first year) and InSAR line of sight measurements (years two to five) and infer that the most likely mechanism of post-seismic stress relaxation is time-dependent distributed creep of viscoelastic material in the lower crust. Since a single relaxation time is not sufficient to model the observed deformation, viscous flow is modelled by a lower crustal Burgers rheology, which has two material relaxation times. The optimum model has a transient viscosity 9 ?? 1017 Pa s, steady-state viscosity 1 ?? 1019 Pa s and a ratio of long term to Maxwell shear modulus of 2:3. This model gives a good fit to GPS stations south of the Kunlun Fault, while displacements at stations north of the fault are over-predicted. We attribute this asymmetry in the GPS residual to lateral heterogeneity in rheological structure across the southern margin of the Qaidam Basin, with thinner crust/higher viscosities beneath the basin than beneath the Tibetan Plateau. Deep afterslip localized in a shear zone beneath the fault rupture gives a reasonable match to the observed InSAR data, but the slip model does not fit the earlier GPS data well. We conclude that while some localized afterslip likely occurred during the early post-seismic phase, the bulk of the observed deformation signal is due to viscous flow in the lower crust. To investigate regional variability in rheological structure, we also analyse post-seismic displacements following the 1997 Manyi earthquake that occurred 250 km west of the Kokoxili rupture. We find that viscoelastic properties are the same as for the Kokoxili area except for the transient viscosity, which is 5 ?? 1017 Pa s. The viscosities estimated for the

  4. Strike-slip fault network of the Huangshi structure, SW Qaidam Basin: Insights from surface fractures and seismic data

    Science.gov (United States)

    Cheng, Xiang; Zhang, Qiquan; Yu, Xiangjiang; Du, Wei; Liu, Runchao; Bian, Qing; Wang, Zhendong; Zhang, Tuo; Guo, Zhaojie

    2017-01-01

    The Huangshi structure, as one of the NWW-trending S-shaped structures in the southwestern Qaidam Basin, holds important implications for unraveling the regional structural pattern. There are four dominant sets of surface strike-slip fractures at the core of the Huangshi structure. The fractures with orientations of N28°E, N47°E and N65°E correlate well with conjugate Riedel shears (R‧), tension fractures (T) and Riedel shears (R) in the Riedel shear model, respectively. Two conjugate strike-slip fracture sets occur at the surface of the Hongpan structure (secondary to the Huangshi structure) and the southwestern part of the Huangshi structure. In seismic sections, the Huangshi structure is present as a positive flower or Y-shaped structure governed by steeply dipping faults, whereas Hongpan and Xiaoshaping structures, located symmetrically to the Huangshi structure, are thrust-controlled anticlines. The Riedel shear pattern of surface strike-slip fractures, the positive flower or Y-shaped structure in seismic sections and the NW-trending secondary compressional anticlines consistently demonstrate that the Huangshi structure is dominated by left-lateral strike-slip faults which comprise a strike-slip fault network. Considering the similar S-shaped configuration and NWW trend of structures across the southwestern Qaidam Basin, it can be further speculated that these structures are also predominantly of left-lateral strike-slip types.

  5. Paleocene-Early Eocene uplift of the Altyn Tagh Mountain: Evidence from detrital zircon fission track analysis and seismic sections in the northwestern Qaidam basin

    Science.gov (United States)

    Wang, Yadong; Zheng, Jianjing; Zheng, Youwei; Liu, Xingwang; Sun, Guoqiang

    2015-12-01

    Most existing tectonic models suggest that the deformation and uplift of the northern Tibetan Plateau is the latest crustal response to the collision of the India Plate and Eurasian Plate. The tectonic evolution of Altyn Tagh Mountain (hereafter called simply the "Altyn Tagh"), on the northern margin of the Tibetan Plateau, has attracted considerable scientific attention. In this study, we use fission track age dates of detrital zircons from the northwestern Qaidam basin together with sedimentary observations to understand more fully the Cenozoic tectonic uplift of the Altyn Tagh. Detrital zircons from five borehole samples distributed in different folds in the northwestern Qaidam basin yielded ages mainly ranging from 88.5 to 49.2 Ma, older than their sedimentary deposition ages (43.8-22 Ma). The binomial distribution in grain age fitted peaks was generally dominated by one young peak, P1, which varied from 73.6 to 47.2 Ma. A thinning of the Cenozoic Lulehe Formation (53.5-43.8 Ma) stretched from the inner Qaidam basin to the slopes of the Altyn Tagh in the seismic sections of the northwestern Qaidam basin. Based on magnetostratigraphic dating, there was a hiatus in sedimentation in the Qaidam basin between 65 Ma and 54 Ma; this was confirmed by seismic profiles and borehole data, which show an unconformity between the Mesozoic Quanyagou Formation and the Lulehe Formation. Combined with an analysis of provenance, the detrital zircon young peak age and the sedimentary record revealed that the most significant regional uplift of the Altyn Tagh occurred during the Paleogene-Early Eocene, almost coinciding with the collision of the Indian and Eurasian plates between 65 Ma and 44 Ma.

  6. Geochemical Characteristics and Origin of Natural Gases in the Qaidam Basin, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Sixty-five natural gas samples were collected from 19 oil-gasfields in the Qaidam basin, China. The chemical composition and carbon isotope values of the samples were measured, and the geochemical characteristics and origin of the natural gases were studied. The gases can be divided into biogenic gases, sapropelic oil-type gases, mixed type oil-type gases, coal-type gases and mixed gas. The δ13C1 values of the biogenic gases are very small and the C2+ contents of them are very low, ranging from -68.2‰ to -61.8‰ and 0.06% to 0.20% respectively. They have heavy δD and δ13CCO2, showing a CO2 reduction pathway. They are distributed in the East depression region and derived from the Quaternary source rocks. The sapropelic oil-type gases have small δ13C2 values and high C2+ ranging from -36.6‰ to -28.6‰ and from 33.01% to 47.15% respectively. The mixed type oil-type gases have δ13C2 values and C2+ contents varying from -28.6‰ to -24.8‰ and from 4.81% to 26.06% respectively. Both sapropelic oil-type gases and mixed type oil-type gases are associated with oil-type oils, distributed in the West depression region and derived from the Tertiary saltwater lacustrine sapropelic source rocks and humic source rocks respectively. The δ13C2 values of the coal-type gases are extremely high and the C2+ contents are very low, changing from -23.3‰ to -12.5‰ and from 0.06% to 18.07% respectively. The coal-type gases in the Nanbaxian gasfield and the Lenghu oil-gasfields in the North fault block belt are derived from the Middle Jurassic coal-measures source rocks, whereas those in the West depression region are derived from the Tertiary saltwater lacustrine humic source rocks. Compared with some other basins in China, the natural gases there have obviously heavier δ13C due to the heavier δ13C of different types of kerogens of the Tertiary saltwater lacustrine source rocks in the West depression region of the basin. The mixing of natural gases is common in the West

  7. The mid-Miocene structural conversion within the NE Tibetan Plateau from new proof of the interaction between two conflicting fault systems in the western Qaidam Basin

    Science.gov (United States)

    Zhao, H.; Wu, L.; Xiao, A.

    2016-12-01

    We present a detailed structural analysis on the fault geometry and Cenozoic development in the Dongping area, northwestern Qaidam Basin, based on the precise 3-D seismic interpretation, remote sensing images and seismic attribute analysis. Two conflicting fault systems distributed in different orientations ( EW-striking and NNW-striking) with opposing senses of shear are recognized and discussed, and the interaction between them provides new insights to the intracontinental deformation of the Qaidam Basin within the NE Tibetan Plateau. The EW-striking fault system constitutes the south part of the Altyn left-slip positive flower structure. Faulting on the EW-striking faults dominated the northwestern Qaidam since 40 Ma in respond to the inception of the Altyn Tagh fault system as a ductile shear zone, tilting the south slope of the Altyn Tagh. Whereas the NNW-striking fault system became the dominant structures since the mid-Miocene ( 15 Ma), induced by the large scale strike-slip of the Altyn Tagh fault which leads to the NE-SW directed compression of the Qaidam Basin. Thus it evidently implies a structural conversion taking place within the NE Tibetan Plateau since the mid-Miocece ( 15 Ma). Interestingly, the preexisting faults possibly restrained the development of the later period faults, while the latter tended to track and link to the former fault traces. Taken the large scale sinistral striking-slip East Kunlun fault system into account, the late Cenozoic intracontinental deformation in the Qaidam Basin showing the dextral transpressional attribute is suggested to be the consequence of the combined effect of its two border sinistral strike-slip faults, which furthermore favors a continuous and lateral-extrusion mechanism of the growth of the NE Tibetan Plateau.

  8. Heavy mineral compositions and zircon U-Pb ages of Cenozoic sandstones in the SW Qaidam basin, northern Tibetan Plateau: Implications for provenance and tectonic setting

    Science.gov (United States)

    Zhu, Wen; Wu, Chaodong; Wang, Jialin; Zhou, Tianqi; Li, Jijun; Zhang, Changhao; Li, Linlin

    2017-09-01

    The Qaidam basin is the largest intermountain basin within the Tibetan Plateau. The spatio-temporal evolution of the basin and the provenances of the deposits in the SW Qaidam basin were greatly influenced by the boundary ranges. Comprehensive research is needed to identify the relationships between the basin and the surrounding ranges. Therefore, 4682 heavy mineral data from 70 wells and 720 detrital zircon ages from 8 samples were used to investigate the provenances of the deposits in the SW Qaidam basin and to further constrain the tectonic evolution of the boundary ranges. The heavy mineral data, zircon U-Pb ages, and paleocurrent data indicate that the Qimen Tagh Range and the Altyn Tagh Range were two provenances of the sediments deposited in the SW Qaidam basin during the Cenozoic. The variations of heavy mineral assemblages and ZTR index (100 ∗ (zircon + tourmaline + rutile)/total transparent heavy minerals) on the northern flank of the Qimen Tagh Range suggest that the Qimen Tagh Range experienced rapid uplift in the Early to Middle Miocene. Furthermore, according to the greatly increased quantities of epidote and hornblende sourced from the Altyn Tagh Range and the obvious decrease in the ZTR index values, the Altyn Tagh Range underwent fast uplift in the Late Oligocene to Early Miocene. In addition, based on the ages of the granitic plutons in the Altyn Tagh Range and the zircon ages in the Ganchaigou and Qigequan sections, the strike-slip movement of the Altyn Tagh Fault (ATF) initiated during or no later than the Middle Eocene, resulting in the ATF offsets of ca. 200 km between the Middle Eocene and the Miocene and of ca. 345 km between the Middle Eocene and the present.

  9. Evidence for Tibetan Plateau Uplift in Qaidam Basin before Eocene-Oligocene Boundary and Its Climatic Implications

    Institute of Scientific and Technical Information of China (English)

    Pei Junling; Sun Zhiming; Wang Xisheng; Zhao Yue; Ge Xiaohong; Guo Xinzhuan; Li Haibing; Si Jialiang

    2009-01-01

    Geometry analysis of the Hongsanhan (红三旱) Section in the northwestern Qaidam basin illustrates the typical growth strata in the Xiaganchaigou (下干柴沟) Formation. The age and sedimentation rates of the Xiaganchaigou and the Shangganchaigou (上干柴沟) formations were determined by the high-resolution magnetostratigraphy. This result shows that the growth strata began to form at ca. 38.0 Ma and increased sedimentation rates occurred at ca. 37.0 Ma. The uplift of the Tibetan plateau before the Eocene-Oligocene boundary is confirmed, which enables us to better understand the relationship between climatic changes and the tectonic uplift. This uplift event could have resuited in the regional drying by blocking the moisture and contributed to the Eocene-Oligocene boundary global cooling event due to the declining atmospheric CO2 concentrations by increased weathering of the mountains.

  10. Clay mineralogical and geochemical constraints on late Pleistocene weathering processes of the Qaidam Basin, northern Tibetan Plateau

    Science.gov (United States)

    Miao, WeiLiang; Fan, QiShun; Wei, HaiCheng; Zhang, XiYing; Ma, HaiZhou

    2016-09-01

    At the Qarhan Salt Lake (QSL) on the central-eastern Qaidam Basin, northern Tibetan Plateau, Quaternary lacustrine sediments have a thickness of over 3000 m and mainly composed of organic-rich clay and silty clay with some silt halite and halite. In this study, a 102-m-long sediment core (ISL1A) was obtained from the QSL. Combining with AMS 14C and 230Th dating, clay minerals and major-element concentrations of ISL1A were used to reconstruct the weathering process and trend of the QSL since late Pleistocene. The results reveal that the clay mineral from rocks, gneisses and schists of Eastern Kunlun Mountains on the south of the QSL. The abundance of illite mineral displays an opposite fluctuation trending with that of smectite, chlorite and kaolinite mineral in ISL1A, which is significantly different from the monsoon-controlled regions. Moreover, higher values of illite, kaolinite/chlorite and illite/chlorite ratios, and lower values of smectite, chlorite and kaolinite minerals occurred in 83-72.5 ka, 68.8-54 ka, 32-24 ka, corresponding to late MIS 5, late MIS 4, early MIS 3 and late MIS 3, respectively. These three phases were almost similarly changed with oxygen isotopes of authigenic carbonates and pollen records in ISL1A, which implies that stronger chemical weathering corresponds to higher effective moisture periods of source region in the Qaidam Basin. Based on chemical weathering index and (Al2O3-(CaO + Na2O)-K2O) diagram, chemical weathering degree in this study area takes a varying process from low to intermediate on the whole.

  11. Carbon and oxygen isotopic constraints on paleoclimate and paleoelevation of the southwestern Qaidam basin, northern Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Lin-Lin Li

    2017-09-01

    Full Text Available We investigate the growth of the northern Tibetan Plateau and associated climate change by applying oxygen and carbon isotopic compositions in Cenozoic strata in the southwestern Qaidam basin. The X-ray diffraction and isotopic studies reveal that the carbonate minerals are mainly authigenic and they do not preserve any evidence for detrital carbonate and diagenesis. The isotope data show large fluctuations in the δ18O and δ13C values in the middle–late Eocene, indicating relatively warm and seasonal dry climate. The positive correlation of the δ18O and δ13C values in the Oligocene and the positive shift of the δ13C values from the Eocene to Oligocene suggest that the climate changed to arid in the Oligocene. However, the δ18O values show negative shift, which is closely related to the global cooling event. During the Miocene, the δ13C values vary between –2‰ and –4‰, whereas the δ18O values show continuous negative shift. The mean δ18O values decrease from –8.5‰ in the early Miocene to –10.0‰ in the late Miocene. The stable isotope-based paleoaltimetry results suggest that the elevation of the southwestern Qaidam basin was approximately 1500 m in the middle–late Eocene and Oligocene. Subsequently, during Miocene the crustal uplift process started and the elevation reached approximately 2000 m in the early Miocene and 2500 m in the late Miocene, which suggests large-scale growth of the northern Tibet Plateau during the Miocene.

  12. Cambrian Ichnofossils from the Zhoujieshan Formation (Quanji Group) Overlying Tillites in the Northern Margin of the Qaidam Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    Yue Wang; Xunlian Wang; Ye Wang

    2015-01-01

    The Quanji Group is composed of siliciclastics and carbonates and was deposited on a relatively stable block, in the northern margin of the Qaidam Basin, NW China. It is one of the research hotspots in the Qilian-Qinling-Kunlun tectonic zones. However, it has long been argued whether the up-per Quanji Group should be assigned to the Precambrian or the Cambrian for lack of convincing fossil evidence. The discovery of ichnofossils, including Rusophycus, Cruziana, Dimorphichnus, Treptichnus, Skolithos, Arenicolites, Palaeophycus, and Helminthopsis, indicates that the upper member of the Zhou-jieshan Formation (top Quanji Group) is Cambrian in age, and at least above the Treptichnus (Phycodes) pedum Biozone, the lowermost biozone in the Cambrian. The lower member of the Zhoujieshan Forma-tion should belong to the Cambrian. During the time when the upper member of the Zhoujieshan For-mation was deposited, the northern margin of the Qaidam Basin was dominated by the Cruziana Ichno-facies, characterizing a lower-energy shelf (shallow) sea environment with moderate-rich oxygen con-tents. In addition, the conglomerates in the Hongtiegou Formation of the Quanji Group underlying the Zhoujieshan Formation were generally regarded as tillites. However, the dolostones of the lower member of the Zhoujieshan Formation are, in lithology and geochemistry, different from the typical cap-dolostones of the Doushantuo Formation in South China, so it is necessary to further study the ori-gins of the lower member of the Zhoujieshan Formation and the conglomerates of the Hongtiegou For-mation.

  13. Benthic macro red alga: A new possible bio-precursor of Jurassic mudstone source rocks in the northern Qaidam Basin, northwestern China

    Institute of Scientific and Technical Information of China (English)

    CAO Jian; BIAN LiZeng; HU Kai; LIU YunTian; WANG LiQun; YANG ShaoYong; CHEN Yan; PENG XiaoQun

    2009-01-01

    Whether benthic macroalga can be an Important type of bio-precursor of source rocks is a contentious Issue in source-rock studies, and has not been well understood. This paper represents a case study of Jurassic mudstone source rocks from the northern Qaidam Basin, northwestern China, in which the benthic macro red algae were recognized for the first time based on combined organic petrological and biomarker works. We found not only cystocarpa in the algae, representative of rhodophyta, but also diahopanes, which are diagnostic biomarkers of such algae. Thus, as many reservoired oils in the northern Qaidam Basin contain abundant diahopanes, it may indicate that the red algae have contributed to hydrocarbon accumulation. This was confirmed by integrated geological and geochemical analyses. Hence, this study provides new evidence for macroalga-generated hydrocarbons.

  14. Benthic macro red alga:A new possible bio-precursor of Jurassic mudstone source rocks in the northern Qaidam Basin,northwestern China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Whether benthic macroalga can be an important type of bio-precursor of source rocks is a contentious issue in source-rock studies,and has not been well understood.This paper represents a case study of Jurassic mudstone source rocks from the northern Qaidam Basin,northwestern China,in which the benthic macro red algae were recognized for the first time based on combined organic petrological and biomarker works.We found not only cystocarps in the algae,representative of rhodophyta,but also diahopanes,which are diagnostic biomarkers of such algae.Thus,as many reservoired oils in the northern Qaidam Basin contain abundant diahopanes,it may indicate that the red algae have contributed to hydrocarbon accumulation.This was confirmed by integrated geological and geochemical analyses.Hence,this study provides new evidence for macroalga-generated hydrocarbons.

  15. The paleoclimate change of Qaidam Basin during the last 2.85 Ma recorded by Gamma-ray logging

    Institute of Scientific and Technical Information of China (English)

    LIU; Zechun

    2001-01-01

    [1]Johan, H., ten Veen, Astronomically forced variations in gamma-ray intensity: Late Miocene hemipelagic successions in the eastern Mediterranean basin as a test case, Geology, 1998, 24(1): 15[2]Herbert, T. D., Mayer, L. A., Long climatic time series from sediment physical property measurement, Journal of Sedimentary Petrology, 1991, 61: 1089.[3]Liu Zechun, Wang Yongjin, Yang Fan et al., Stratigraphic and geochronologic analyses of the Quaternary deposits in the three-lake region of Qaidam Basin, Science in China, Ser. B, 1991, 34(8): 987.[4]Yang, F., Proc. 1st nat. Symp. In China, Micropaleontology (in Chinese), 1979, 7(3): 46.[5]Liu Zechun, Wang Yongjin, Chen Ye et al., Magnetostratigraphy and sedimentologically derived geochronology of the Quaternary lacustrine deposits of a 3000 m thick sequence in the central Qaidam Basin, Western China, Palaeogeography Palaeoclimatology, Plaeoecology, 1998, 140: 459.[6]Debisher, E., Shaw, J., Wang, J. T., Paleomagnetic age of the borehole No. 1 of Dabuxun Lake, Qaidam Basin, J. Glacier Cryopedol (in Chinese), 1985, 7(3): 227[7]Wang Sumin, Feng Ming, The relationship between environment change and SE monsoon strengh, Daihai Lake, Inner Mongolia. Science in China, Ser. B, 1992, 35(6): 722[8]Shackleton, N. J., Opdyke, N. D., Oxygen isotope and palaeomagnetic evidence for early northern hemisphere glaciation, Nature, 1977, 270: 216[9]Wei Keqing, Lin Ruifeng, The paleoclimatic signification along the section of d18O of autogenetic carbonate deposited in inner land close lake, Geochimica (in Chinese), 1995, 24(3): 215[10] Zhang Penxi, Zhang Baozhen, Qian Guimin et al., The study of paleoclimatic parameter of Qinhai Lake since Holocene, Quaternary Science (in Chinese), 1994, (3): 226[11]Imbrie, J., Hays, J. D., Martinson, D. G. Et al., The orbital theory of Pleistocene climate: support from a revised chronology of the marine δ18O record, Milankovitch and Climate (part 1), Dordrecht

  16. Simulation experiment on hydrocarbon generating potential of various source rocks on the northern margin of the Qaidam Basin, Qinghai, China

    Institute of Scientific and Technical Information of China (English)

    LI Xin; WANG Dongliang; LIU Baoquan; REN Chunling; GUO Jianying; SU Xuefeng; WANG Jian

    2008-01-01

    The northern margin of the Qaidam Basin is one of the main oil-gas exploration areas in western China, where source rocks are composed mostly of Middle and Lower Jurassic dark mud shale, carbargillite and coal. A large number of subsurface and outcrop samples differing in lithology with different types of organic matter were selected for resource evaluation, research and calculation. And among them, 13 samples were used for simulation experiment on hydrocarbon generating potential of various source rocks. At first, two kinds of heating modes were compared through simulation experiment, including single temperature-step heating and continual heating. Perhaps, the process of hydrocarbon generation and expulsion occurred naturally between a close system and an open system. In addition, the first heating mode was convenient, and all its reaction products were involved in the whole thermal evolution, and the final simulation experimental results were basically in consistency with the natural evolution trend. Therefore, the first heating mode was adopted and the hydrocarbon yield of every sample was worked out. According to the type and lithology of organic matter and the hydrocarbon yield of samples for simulation experiment, hydrocarbon generation and expulsion mode with three kinds of lithology and five types of source rock has been established to provide the basis for hydrocarbon generation evaluation, research and resource calculation.

  17. Investigations on boron isotopic geochemistry of salt lakes in Qaidam basin, Qinghai

    Digital Repository Service at National Institute of Oceanography (India)

    Xiao, Y.K.; Shirodkar, P.V.; Liu, W.G.; Wang, Y.H.; Jin, L.

    of brine and are related to boron origin, the corrosion of salt and to certain chemical constituents. The distribution of boron isotopes in Quidam Basin showed a regional feature: salt lake brines in the west and northwest basin have the highest d11B values...

  18. Biogas charging and dissipating process and its accumulation in the Sebei gasfield,Qaidam Basin,China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Sebei gasfield is the largest biogas accumulation found in China and many reservoirs and seal rocks superposed on a syndepositional anticline in Quaternary.The biogas charging and dissipating process and its distribution have been a research focus for many years.The authors suggest a diffusing and accumulating model for the biogas,as they find that the shallower the gas producer,the more methane in the biogas,and the lighter stable carbon isotope composition of methane.Based on the diffusing model,diffused biogas is quantitatively estimated for each potential sandy reservoir in the gasfield,and the gas charging quantity for the sandy reservoir is also calculated by the diffused gas quantity plus gas reserve in-place.A ratio of diffusing quantity to charging quantity is postulated to describe biogas accumulating state in a sandy reservoir,if the ratio is less than 0.6,the reservoir forms a good gas-pool and high-production layer in the gasfield,which often occurs in the reservoirs deeper than 900 m;if the ratio is greater than 0.6,a few gas accumulated in the reservoir,which frequently exists in the reservoirs shallower than 900 m.Therefore,a biogas accumulation model is built up as lateral direct charging from gas source for the sands deeper than 900 m and indirect charging from lower gas-bearing sands by diffusion at depth shallower than 900 m.With this charging and diffusion quantitative model,the authors conducted re-evaluation on each wildcat in the central area of the Qaidam Basin,and found many commercial biogas layers.

  19. The effect of water saturation on methane breakthrough pressure: An experimental study on the Carboniferous shales from the eastern Qaidam Basin, China

    Science.gov (United States)

    Zhang, Cheng; Yu, Qingchun

    2016-12-01

    Breakthrough pressure plays an important role in shale gas flow, mining, and caprock evaluation. A series of breakthrough experiments were conducted under different water saturation conditions for four shales taken from the Carboniferous Hoit Taria Formation in the eastern Qaidam Basin, China to investigate the influence of water saturation on breakthrough pressure. Relevant geochemical tests (mineral composition, clay content, total organic carbon, thermal maturity and vitrinite reflectance) and micro structural characteristics of micro pores were also conducted. Breakthrough pressures under at least five different water saturations (from 0 to 100%) were obtained and relationship between breakthrough pressure and water saturation was fitted for each sample. We found that breakthrough pressure increases exponentially with water saturation. The decrease in effective pore diameter caused by both the bound water films and the swelling of the clay minerals resulted in the increase in the breakthrough pressure. After water saturation reached about 60%, breakthrough pressure increased rapidly from connectivity reduction, caused by the sealing off of smaller pores and partial water saturation of the macropores. By analyzing the correlation between breakthrough pressure and pore structure characteristics, breakthrough pressure is inversely related to porosity, and is primarily affected by macropores. Because macropores consist of many microfractures with lengths up to dozens of micrometers, they determine the porosity and then affect the connectivity of the rock. Correlation analysis between the mineral compositions and breakthrough pressure showed that TOC content exhibits a positive correlation with breakthrough pressure, but neither quartz content nor the clay mineral content exhibits a correlation. By combining this information with Field Emission Scanning Electron Microscope results, we found that microfractures are easily created where the TOC (total organic carbon

  20. A record of Quaternary humidity fluctuations on the NE Tibetan Plateau based on magnetic susceptibility variations in lacustrine sediments of the Qaidam Basin

    Science.gov (United States)

    Herb, Christian; Koutsodendris, Andreas; Zhang, Weilin; Appel, Erwin; Pross, Jörg; Fang, Xiaomin

    2013-04-01

    Magnetic susceptibility (?) and other magnetic proxies play an important role in paleoclimatic studies as they hold the potential for high-resolution records of past environmental change. Nevertheless, it is necessary to understand the cause of the variation in magnetic proxies by comparing them to more direct climate proxies such as pollen or stable isotopes. In this study we have compiled a high-resolution magnetic proxy dataset of the ca. 940-m-long core SG-1, which was drilled in the lacustrine sediments of the western Qaidam Basin on the northeastern Tibetan Plateau. Our record spans the entire Quaternary (~2.8 to 0.1 Ma). The magnetic susceptibility record is compared to the Artemisia/Chenopodiaceae (A/C) ratio, which is used to discriminate between dry and more humid phases in the Qaidam Basin, based on (i) 41 samples spanning the Middle Pleistocene Transition (MPT; ~1 Ma BP) and (ii) additional 40 samples selected from intervals of minimum and maximum ? values throughout the core. For the drill core SG-1, we observe a high correlation of the A/C ratio with ? results: minima of ? correspond to maxima of the A/C ratio (representing more humid phases) and vice versa. Additionally, spectral analysis of the ? record shows the emergence of the 100-ka Milankovitch cycle after the MPT. This testifies to the fact that cyclic variation of ? represents a response to global climate change.

  1. 柴北缘西段新近系上干柴沟组沉积相特征分析%Sedimentary facies in the Neogene Upper Ganchaigou Formation on the northern margin of the Qaidam Basin, Qinghai

    Institute of Scientific and Technical Information of China (English)

    刘琪; 潘晓东; 李凤杰

    2011-01-01

    根据野外露头、岩心观察及录井、测井资料,研究了柴北缘西段新近系上干柴沟组沉积相类型和沉积特征.结果表明:上干柴沟组发育冲积扇、扇三角洲、辫状河、辫状河三角洲、湖泊及颗粒流等六种沉积相类型,其中在鄂博梁-冷湖-潜西发育了一套扇三角洲-湖泊沉积体系,在马海-南八仙地区发育冲积扇-辫状河-辫状河三角洲-湖泊沉积体系.%The examination of the sedimentary facies is based on the field outcrops, core observation and well logs for the Neogene Upper Ganchaigou Formation on the northern margin of the Qaidam Basin, Qinghai. The Upper Ganchaigou Formation is built up of the alluvial fan, fan delta, braided stream, braided delta, lacustrine facies and grain flow deposits. Two depositional systems have been recognized, including the fan delta-lacustrine depositional system in the Eboliang-Lenghu-Qianxi zone, and alluvial fan-braided stream-braided delta-lacustrine depositional system in the Mahai-Nanbaxian zone. The results of research in the western part of the northern margin of the Qaidam Basin may provide reliable geological information for further petroleum exploration.

  2. 柴达木盆地及其邻区早—中二叠世构造-岩相古地理格局%Early-middle Permian Tectonic-lithofacies Palaeogeographic Characteristics in Qaidam Basin and Its Adjacent Areas

    Institute of Scientific and Technical Information of China (English)

    陈守建; 陈奋宁; 计文化; 李荣社; 洛长义; 刘荣利; 李国栋

    2012-01-01

    通过大量野外观察、分析测试和综合研究,结合覆盖全区不同比例尺的区域地质调查资料,对柴达木盆地及其邻区早—中二叠世构造-岩相古地理格局进行了研究,并探讨了其形成机制.结果表明:柴达木盆地及其邻区中、北部早—中二叠世为陆内盆山-裂谷系统,主体处于伸展构造背景,总体表现为堑垒相间的构造古地理格局;南部为巴颜喀拉洋盆,早—中二叠世是巴颜喀拉洋盆扩张最为剧烈且规模最大的时期,巴颜喀拉洋盆中洋岛、海山遍布;早—中二叠世晚期强烈的华力西构造运动使古板块间的相对运动加剧,巴颜喀拉洋盆大洋岩石圈板块向北强烈俯冲,形成东昆仑陆缘岩浆弧及其南部增生带,东昆仑陆缘岩浆弧岩浆活动十分强烈,宗务隆山—西秦岭陆源裂谷盆地进一步发育,形成十分复杂的构造-岩相古地理格局.早—中二叠世是研究区地球动力学机制从强烈扩张到强烈汇聚的转折时期,加强其构造-岩相古地理研究对建立该区地层序列、探讨其地质演化历史以及指导找矿等均具有重要意义.%Through the field observation, the analysis of test data, the comprehensive regional geological survey and the previous research result, the forming mechanism and tectonic-lithofacies paleogeography during the Early-middle Permian in Qaidam Basin and its adjacent areas were discussed. The results showed that the Early-middle Permian in the central and northern parts of Qaidam Basin and its adjacent areas was intracontinental basin-and-range and rift valley system, and mainly located on extensional tectonic setting, and the tectonic paleogeography was graben and horst alternately! the Early-middle Permian in the southern part was the period with most violent expansion cosmically in Bayankala ocean basin, and ocean-island and seamount were all over the ocean basinj the strong Hualixi tectonic movement in the late of Early

  3. Surface pollen in the east of Qaidam Basin%柴达木盆地东部表土花粉分析

    Institute of Scientific and Technical Information of China (English)

    陈辉; 赵东升; 吕新苗

    2006-01-01

    Pollen analysis of 23 surface samples in the east of Qaidam Basin reveals the characteristics of pollen assemblages and their relationships with vegetation and climate. In pollen assemblages, Chenopodiaceae and Artemisia are preponderant types in all the samples, and Ephedra, Gramineae and Compositae are common types. The results of DCA (Detrended Correspondance Analysis) and Correlation Analysis show different pollen assemblages indicate different vegetations, coincided with respective vegetation types. A/C (Artemisia/Chenopodiaceae) in the desert can indicate the aridity. Depending on the aridity, the vegetation communities are divided into four groups: severe drought group, moderate drought group, slight drought group and tropophilous group. A/C value is less 0.2 in the severe drought group, 0.2-0.5 in the moderate drought group, 1.63 in the slight drought group and 5.72 slight-wetness group.

  4. Paleoclimatic implications of magnetic susceptibility in Late Pliocene-Quaternary sediments from deep drilling core SG-1 in the western Qaidam Basin (NE Tibetan Plateau)

    Science.gov (United States)

    Zhang, Weilin; Appel, Erwin; Fang, Xiaomin; Yan, Maodu; Song, Chunhui; Cao, Liwan

    2012-06-01

    Lake sediments are important archives of paleoclimate change and erosion history. A 938.5 m long core (SG-1) of lacustrine sediments, dated at 2.77 Ma to 0.1 Ma, was obtained from the western Qaidam Basin in the northeastern Tibetan Plateau, consisting of dark grayish mudstone and grayish siltstone, intercalated with salts and fine sandstones in the upper part. Magnetic susceptibility data, combined with detailed rock magnetic properties, were analyzed for revealing the significance of ferro(i)magnetic concentration for past changes of climate and erosion. Mass-specific susceptibility (χ) shows a striking cyclic and long-term variation. Samples with high χ values are dominated by magnetite and maghemite with pseudo-single-domain properties. In contrast, samples with low χ values contain maghemite from single-domain to multidomain and, additionally, a significant fraction of hematite. The driving mechanism of χ variation can be explained by three alternative models: (1) different source regions with alternations of wind and cryoclastic erosion in a wider hinterland (dry-cold climate) and surface runoff erosion from a narrower area (more humid climate) and (2 and 3) low-temperature oxidation, occurring either in the lake sediments (dry climate) or in the catchment area during weathering (more humid climate). Trends of χ match with changes in sedimention rates and are roughly synchronous with the deep-sea δ18O record on a glacial-interglacial timescale. Therefore, the concentration of magnetic minerals in the western Qaidam Basin sediments is likely controlled by both tectonic influence and paleoenvironmental changes but can be best interpreted by alternations and trends of dry-cold and more humid periods due to Asian drying and global cooling.

  5. Isotopic composition of gypsum hydration water in deep Core SG-1, western Qaidam basin (NE Tibetan Plateau), implications for paleoclimatic evolution

    Science.gov (United States)

    Li, Jiao; Li, Minghui; Fang, Xiaomin; Zhang, Gengxin; Zhang, Weilin; Liu, Xiaoming

    2017-08-01

    The oxygen and hydrogen isotopic compositions of gypsum hydration water can be useful for determining the isotopic composition of the original brine from which gypsum precipitated. However, relatively few long-term and continuous records of the stable isotope geochemistry of gypsum hydration water in arid regions have been reported. We measured the δ18O and δD of primary gypsum hydration water from a 938.5 m-long deep core (SG-1) in the western Qaidam Basin to study the mechanisms that contributed to gypsum formation and to reconstruct potential paleoclimatic change. The measured δ18O and δD ranged from - 4.21‰ to 8.69‰ and from - 72.77‰ to 49.73‰, respectively. The linear relationship between δ18O and δD indicates that meteoric water was the original source of the gypsum hydration water. The gradient of 5.39 for the δ18O and δD plots is lower than that of global meteoric water, suggesting that paleo-lakewater evaporated and became a CaSO4-rich brine leading to gypsum deposition. The evaporation/precipitation (E/P) ratio played an important role in determining δ18O and δD. The oscillations noted in the δ18O and δD of the gypsum hydration water imply that: (a) there was a long-term and stepwise aridification after 2.2 Ma in the western Qaidam Basin; and (b) there were three increasingly dry phases at 2.2-1.2 Ma, 1.2-0.6 Ma, and 0.6-0.1 Ma, with two cold and dry events at 1 Ma and 0.6 Ma. Global cooling, especially during the Mid Pleistocene Climate Transition event (MPT), may have been the primary cause of the aridification recorded in core SG-1 in the Asian inland.

  6. Origin and lateral migration of linear dunes in the Qaidam Basin of NW China revealed by dune sediments, internal structures, and optically stimulated luminescence ages, with implications for linear dunes on Titan: discussion

    Science.gov (United States)

    Rubin, David M.; Rubin, Alan M.

    2013-01-01

    Zhou et al. (2012) proposed that longitudinal dunes in the Qaidam Basin, China, formed like yardangs: by erosion into sediment that was not deposited by those dunes. Because erosion occurs on the upwind flanks of most migrating dunes (Rubin and Hunter, 1982, 1985), the key to demonstrating a yardang-like origin is to show that the dunes did not deposit the strata that they contain. Zhou et al. made this argument by proposing that: (1) The dunes have not deposited cross-strata in the past 810 yr. (2) Cross-bedding within the dunes was not deposited by the dunes on the present-day land surface, but rather by older dunes that had a different morphology. (3) The present dunes are a later generation, “most likely of erosional origin similar to yardangs with orientations controlled by strikes of joints,” (p. 1147). (4) Rates of deflation in the dune field have been extremely high for the past 810–2440 yr. This commentary reviews these conclusions, reviews contradictory observations, and considers alternative interpretations.

  7. Climate variability recorded by n-alkanes of paleolake sediment in Qaidam Basin on the northeast Tibetan Plateau in late MIS3

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Here we combine n-alkanes preserved in a shell bar section from Qarhan paleolake, Qaidam Basin with the other sedimentary proxies to elucidate the lake evolution process during the period 39.7 to 17.5 14C ka BP (calibrated age ranges from 43.5 to 22.4 cal. ka BP). In different stages, the n-alkane homologues exhibited different distribution modes indicative of variations in the surrounding vegetation and the hydrologic condition of the lake. The n-alkanes proxies (CPIh, ACLh, Paq) have the same trends as the summer solar insolation variation, implying that the summer insolation is the most important climatic factor driving the environmental changes and also indirectly controls lake evolution on the Tibetan Plateau. CPIh and ACLh as well as the total pollen concentration appear to show a trend comparable with methane concentration record from the GRIP ice core that reflected the Dansgaard-Oeschger events. This demonstrates that the paleoclimate variations in Qarhan area generally agree with global climate change and show rapid oscillations in late MIS3. These findings provide the latest molecular fossil evidence from paleolake sediments to confirm that lake evolution on Tibetan Plateau in late MIS3 was closely associated with enhanced summer insolation.

  8. Post-Seismic Deformation from the 2009 Mw 6.3 Dachaidan Earthquake in the Northern Qaidam Basin Detected by Small Baseline Subset InSAR Technique

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-02-01

    Full Text Available On 28 August 2009, one thrust-faulting Mw 6.3 earthquake struck the northern Qaidam basin, China. Due to the lack of ground observations in this remote region, this study presents high-precision and high spatio-temporal resolution post-seismic deformation series with a small baseline subset InSAR technique. At the temporal scale, this changes from fast to slow with time, with a maximum uplift up to 7.4 cm along the line of sight 334 days after the event. At the spatial scale, this is more obvious at the hanging wall than that at the footwall, and decreases from the middle to both sides at the hanging wall. We then propose a method to calculate the correlation coefficient between co-seismic and post-seismic deformation by normalizing them. The correlation coefficient is found to be 0.73, indicating a similar subsurface process occurring during both phases. The results indicate that afterslip may dominate the post-seismic deformation during 19–334 days after the event, which mainly occurs with the fault geometry and depth similar to those of the c-seismic rupturing, and partly extends to the shallower and deeper depths.

  9. n-alkane distribution coupled with organic carbon isotope composition in the shell bar section, Qarhan paleolake, Qaidam basin, NE Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    Yang PU; Hucai ZHANG; Guoliang LEI; Fengqin CHANG; Mingsheng YANG; Xianyu HUANG

    2009-01-01

    Lipids extracted from lacustrine deposits in the paleolake Qarhan of the Qaidam basin in the northeastern Tibetan Plateau were determined by conventional gas chromatography-mass spectrometry. Several series of biomarkers were identified, mainly including n-alkanes, n-alkan-2-ones, n-alkanoic acids, branched alkanes, triter-penoids and steroids, indicative of various biogenic contributions. On the basis of cluster analysis, the n-C15, n-C17, n-C19 alkanes were proposed to be derived from algae and/or photosynthetic bacteria, the n-C21 n-C23, n-C25 homologues from aquatic plants, and the n-C29, n-C31 homologues from vascular plants. In contrast, the n-C27 alkane is not categorized in the n-C29 and n-C31 group of alkanes, probably due to more complex origins including both aquatic and vascular plants, and/or differential biodegradation. Stratigraphically, layers-2, 4 and 5 were found to show a close relationship in n-alkane distribution, associated with a positive shift in carbon isotope composition of bulk organic matter (δ13Corg), inferring a cold/dry period. Layers-1 and 6 were clustered together in association with a negative δ13Corg excursion, probably indicating a relatively warm/humid climate. The potential coupling between the n-alkane distributions and δ13Corg, suggests a consequence of vegetation change in response to climate change, with the late MIS3 being shown to be unstable, thought to be the climatic optimum in the Tibetan Plateau. Our results suggest that the cluster analysis used in this study probably provides an effective and authentic method to investigate the n-alkane distribution in paleolake sediments.

  10. Carbon and oxygen isotopic records from Lake Tuosu over the last 120 years in the Qaidam Basin, Northwestern China: The implications for paleoenvironmental reconstruction

    Science.gov (United States)

    Li, Xiangzhong; Zhou, Xin; Liu, Weiguo; Wang, Zheng; He, Yuxin; Xu, Liming

    2016-06-01

    Isotopic compositions of total organic carbon (TOC) and authigenic carbonate in lakes have been widely used to reconstruct paleoclimatic changes and the depositional environments of lake sediments. However, since these proxies are often controlled by multiple environmental factors, detailed examinations of modern environmental processes is necessary before further applying them into paleoclimatic studies, especially in arid/semi-arid northwestern China. Here we generate High-resolution multi-proxy sedimentary records from Lake Tuosu, a hydrologically closed, saline and alkaline lake located at the north margin of the Qaidam Basin, through analysis of carbon isotope of TOC, and δ18O and δ13C values of ostracods over the last 120 years. Together with the meteorological data (precipitation and temperature), lake area record, and other tree-ring evidence, we examine how these sedimentary indices respond to changes in hydrologic balance and climate at interannual to decadal timescales. We found that sedimentary δ13Corg values resemble the variation of lake areas of Lake Tuosu over the last 40 years, suggesting that δ13Corg values would be an ideal indicator of lake area/level fluctuations and thus effective moisture variations (precipitation vs. evaporation). However, ostracod δ18O, which was previously used as proxies of effective precipitation, is not well correlated with δ13Corg values in Lake Tuosu. Therefore, the changes of ostracod δ18O values cannot be straightforwardly explained as the effective precipitation. Instead, the isotopic composition of carbonate would be additionally controlled by other factors including isotopic compositions of input water and drainage pattern.

  11. A 1000-year chironomid-based salinity reconstruction from varved sediments of Sugan Lake, Qaidam Basin, arid Northwest China, and its palaeoclimatic significance

    Institute of Scientific and Technical Information of China (English)

    CHEN JianHui; CHEN FaHu; ZHANG EnLou; BROOKS Stephen J; ZHOU AiFeng; ZHANG JiaWu

    2009-01-01

    A 1000-year high-resolution (~10 years) chironomid record from varved sediments of Sugan Lake, Qaidam Basin on the northern Tibetan Plateau, is presented. The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus, and the relatively low-saline-water taxa Procladius and Psectrocladius sordidellus-type. Variations in the chironomid fauna and inferred salinities suggest that over the last millennium, the Sugan Lake catchment has alternated between contrasting climatic conditions, having a dry climate during the period 990-1550 AD, a relatively humid climate during the Little Ice Age (LIA) (1550-1840 AD), and a dry climate again from 1840 AD onwards. At the decadal to centennial scale, a wet event around 1200-1230 AD, interrupting the generally arid period (990-1550 AD), and a dry event around 1590-1700 AD, punctuating the generally humid period (1550-1840 AD), are clearly documented. Trends in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher frequency. The effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China (ANC). The LIA, characterized by generally humid conditions over the west-erly-dominated ANC was distinctly different from that in monsoonal China, implying an "out-of-phase" relationship between moisture evolution in these two regions during the past 1000 years.

  12. Qaidam is Expected to Become China’s New “Capital of Nickel”

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>On January 24, the reporter learned from the Haixi Delegation Review Meeting of the First Session of the 12th Qinghai Province People’s Congress that a large high grade nickel ore de-posit had been discovered in Qaidam Basin, Qinghai Province. This discovery will make Qaidam China’s new "Capital of Nickel".

  13. Origin and evolution of oilfield brines from Tertiary strata in western Qaidam Basin: Constraints from 87Sr/86Sr, δD, δ18O, δ34S and water chemistry

    Institute of Scientific and Technical Information of China (English)

    FAN Qishun; MA Haizhou; LAI Zhongping; TAN Hongbing; LI Tingwei

    2010-01-01

    Chemistry of major and minor elements, 87Sr/86Sr, δD, δ18O and δ34S of brines were measured from Tertiary strata and Quaternary salt lakes in the western Qaidam Basin. The water chemistry data show that all oilfield brines are CaCl2 type. They were enriched in Ca2+, B3+, Li+, Sr2+, Br-, and were depleted in Mg2+, SO42-, which indicated that these brines had the characteristics of deeply circulated water. The relationship between δD and δ18O shows that all data of these brines decline towards the Global Meteoric Water Line (GWL) and Qaidam Meteoric Water Line (QWL), and that the intersection between oilfield brines and Meteoric Water Lines was close to the local spring and fresh water in the piedmont in the western Qaidam Basin. The results suggest that oilfield brines has initially originated from meteoric water, and then might be affected by water-rock metamorphose, because most oilfield brines distribute in the range of metamorphosing water. The 87Sr/86Sr values of most oilfield brines range from 0.71121 to 0.71194, and was less than that in salt lake water (>0.712), but close to that of halite in the study area. These imply that salt dissolution occurred in the process of migration. In addition, all oilfield brines have obviously much positive δ34S values (ranging from 26.46‰ to 54.57‰) than that of salt lake brines, which was caused by bacterial sulfate reduction resulting in positive shift of δ34S value and depleteed SO42- in oilfield brines. Combined with water chemical data and δD, δ18O, 87Sr/86Sr, δ34S values, we concluded that oilfield brines mainly originate from the deeply circulated meteoric waters, and then are affected by salt dissolution, water-rock metamorphose, sulfate reduction and dolomitization during the process of migration. These processes alter the chemical compositions of oilfield brines and accumulate rich elements (such as B, Li, Sr, Br, K and so on) for sustainable utilization of salt lake resources in the Qaidam Basin.

  14. A case for wind enhanced tectonics: Plio-Quaternary sedimentation, erosion, and structural evolution controlled by wind within the Qaidam Basin, China

    Science.gov (United States)

    Heermance, R. V.; Kapp, P. A.; Pullen, A.; Garzione, C. N.

    2012-12-01

    The interplay between tectonics and localized erosion through fluvial and/or glacial processes has been widely documented. Wind erosion, however, has gone largely un-recognized as a potentially important process in this concept. We document an acceleration in shortening in response to wind deflation above actively deforming fault propagation anticlines since ~3.0 Ma in the Qaidam Basin, China. Evidence for this comes from a 1750 m measured section along the southwestern flank of an intra-basin anticline (38.33°N, 93.46°E) and regional cross-sections. Magnetostratigraphy provides age control for prominent stratigraphic and isotopic changes within the section. A positive shift of ~6‰ in the δ18O values of lake carbonates occurs at 1090 m (3.1 Ma), interpreted to be the result of increased aridity at that time. An intraformational angular unconformity, associated with anticline growth, appears at 1172 m (3.0 Ma) and records the initiation of growth strata deposition. At 1235 m (2.6 Ma), a marked lithofacies change to sub-aerial, evaporitic conditions is observed, and is associated with a 3-fold reduction in sedimentation rate. Paleo-yardangs, which are wind-eroded landforms preserved in the stratigraphic record, appear at 1260 m (2.4 Ma). These observations indicate that regional aridification at 3.1 Ma was followed closely by or coincident with fold growth. Facies changes to more evaporitic strata and erosion of the basin floor (based on paleo-yardangs) trailed initial climate and tectonic changes by 500,000-700,000 years. Although the on-lap relationship of post-growth strata implies that syn-tectonic strata may have pinched-out along the flanks of the anticline, our new analysis indicates that at least 1172 m of pre-growth strata must have been eroded from the core of the anticline since 3.0 Ma at a time-averaged rate of ~0.4 mm/year, comparable to fluvial and glacial erosion rates within active tectonic settings. The lack of an integrated fluvial channel

  15. Controlling mechanism of sedimentation-burial historyon oil-gas maturation history——A case study in Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    沈显杰; 汪缉安; 张菊明; 杨淑贞; 沈继英

    1995-01-01

    Three types of practical data are used for basin simulation: stratigraphic column thicknesses interpreted in the light of the common seismic reflecting layers, the percentage of mudy rocks in the column and the statistical heat flow values. A mesh point data read-in technique is used for the region covered by Tertiary strata in the basin A B-T-M computer software is developed for simulating the burial, thermal and oil-gas maturation histories on 703 mesh points. Furthermore, five typical types of oil-gas evolution trends are summarized on the basis of the characteristics of B-T-M evolution graph of each single mesh point. A careful analysis shows that the sedimentation-burial history through differentiated stratum thermal history in the different parts of the basin ultimately controls the temporal sequence and the threshold temperature and depth of oil-gas maturation, as well as the whole evolutionary process of petroleum formation of oil-source rocks from low-maturation, high-maturation through over-ma

  16. 柴西南古近系——新近系盐湖盆地层序地层分析%Sequence Stratigraphic Study of Paleogene and Neogene Salt Lake, Southwestern Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    王宏波; 陈启林; 王朴

    2011-01-01

    Sequence stratigraphic study of the salt lake with lately started and weak foundations in Qaidam Basin is important in many respects. In order to analyze the sequence stratigraphy in Paleogene and Neogene in southwestern Qaidam Basin and provide a foundation for lithologic hydrocarbon reservoir exploration, this paper studies the sequence boundary identification and the sequence classification in Paleogene and Neogene in southwestern Qaidam Basin by using sequence stratigraphic method, and applyin8 outcrop data, core, drilling data and seismic data. It is shown that the classification in terms of 13 long-term circles is reasonable, and there are 4 sequence developing patterns: gentle slope zone, abrupt slope zone, low uplift zone and Lake Basin. And it is also shown that the sequence circle structure plays a significant role in controlling the lithologic trap, the development of sandstone reservoir is closely related to the midterm circle, and favorable reservoirs mainly develop at the bottom of the circle structure with a trend of "becoming deeper upward".%为了探讨柴达木盆地西南古近系-新近系层序地层,为岩性油气藏勘探提供依据,本文在Cross高分辨率层序地层学理论指导下,综合利用露头、岩心、钻井、地震等资料,结合盐湖盆地的沉积特殊性,对柴西南古近系-新近系层序界面进行识别与层序划分.研究认为将柴达木盆地柴西南古近系-新近系地层划分为13个长期旋回更为合理,提出缓坡带、陡坡带、低凸地区和湖盆区4种不同沉积单元的层序发育模式,指出层序旋回结构对岩性圈闭具有重要的控制作用,储集砂岩的发育状况与中期旋回密切相关,有利储层主要发育在旋回结构向上"变深"的非对称型下部.

  17. Biologic Gas Accumulation Mechanism and Exploration Strategy in Sanhu Area,Qaidam Basin%柴达木盆地三湖地区生物气成藏机理与勘探对策

    Institute of Scientific and Technical Information of China (English)

    孙平; 郭泽清; 张林; 田继先; 张绍胜; 曾旭; 孔骅; 杨晶

    2013-01-01

    柴达木盆地三湖地区第四系的形成是在新近纪末期新构造运动作用下,盆地沉积中心由西向东整体迁移的产物.三湖地区第四系具有成岩作用弱、砂泥岩薄互层、源储不分、接替接力生气及由南向北水动力条件较强等独有的地质特征.在这一特有的地质背景下,形成了该区特有的生物气成藏模式:烃源岩持续生烃、水溶气动态成藏.针对该区生物气的勘探对策是:以寻找低幅度构造圈闭为主,围绕北斜坡构造发育区带,加强连片二维地震资料目标处理,寻找低幅度构造目标;同时应继续加强岩性气藏的研究与探索,在确定有利区带、建立地层格架的基础上,采取有效的含气检测手段确定有利岩性目标.%The occurrence of the Quaternary,where located the largest biologic gas field,in the Sanhu area of Qaidam Basin is a product of migration of basin depositional center from west to east under the tectonic movements at the end of Tertiary.The main geological characteristics of Quaternary in Sanhu area include low diagenesis,thin interbed between sand and shale,difficulties in differentiation of source from reservoir,continuous gas generating and strong hydrodynamic action from south to north.Consequently,a special biogenic gas reservoir model for this area comes into being.For example,source rock generates hydrocarbon consistently and dissolved gas in water accumulates dynamically.For the biogenic gas in this area,measures should be taken by paying attention to low amplitude structural trap and strengthening the handling of 2D seismic data around north slope area so as to discover low amplitude structure target.Simultaneously,investigation and research of lithologic gas reservoir should be reinforced.On the basis of definiting favorable area and establishing stratigraphic framework,effective gas detection methods should be taken to determine the lithologic target.

  18. 柴达木盆地致密油藏烃源岩分级解释方法研究%Classification method for Tight oil evaluation in Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    徐永发; 叶高鹏; 米小银; 佘刚; 吕云霞; 李成元

    2015-01-01

    针对柴达木盆地咸化湖盆盆地的特征,研究了烃源岩的基本特征和相关的测井响应特征,提出了利用能谱测井信息建立烃源岩进行函数判别的方法,建立起烃源岩分级判别方法。%The basic characteristics and logging response of hydrocarbon source rock are introduced in this paper based on the characteristics of the saline lake in Qaidam Basin.The function of hydrocarbon source rock is established by the energy spectrum logging information and related classification method is developed as well.

  19. 岩性油气藏勘探的沉积体系域表征技术——以柴达木盆地为例%Characterization of Depositional System Tract for Exploration of Lithologic Pools-An example of Qaidam basin

    Institute of Scientific and Technical Information of China (English)

    吴因业; 江波; 郭彬程

    2004-01-01

    System tract, a basic unit of Ⅲ grade sequence, is a combination of the same term depositional systems controlled by water level changes (lacustrine level or sea level). Petroleum tends to being accumulated in the depositional sand bodies of different system tracts. The type and distribution of lithologic pools could be predicted by characterization of system tracts and analysis of depositional systems. In southwestern Qaidam basin, the characterization of system tracts shows that there exist developed transgressive system tract (TST) and various types of reservoirs such as sand body of deltaic front, lacustrine beach and dam as well as local turbidite of semideep lake. Based on synthetically geologic and seismic analyses, using digital seismic processing techniques (Jason's reservoir inversion, etc.), the sand body distribution could be described, hence predicting that in southwestern Qaidam basin mainly developed the lithologic pools of SB, TU, DT and SS types.

  20. Time-Dependent Afterslip of the 2009 Mw 6.3 Dachaidan Earthquake (China and Viscosity beneath the Qaidam Basin Inferred from Postseismic Deformation Observations

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-08-01

    Full Text Available The 28 August 2009 Mw 6.3 Dachaidan (DCD earthquake occurred at the Qaidam Basin’s northern side. To explain its postseismic deformation time series, the method of modeling them with a combination model of afterslip and viscoelastic relaxation is improved to simultaneously assess the time-dependent afterslip and the viscosity. The coseismic slip model in the layered model is first inverted, showing a slip pattern close to that in the elastic half-space. The postseismic deformation time series can be explained by the combination model, with a total root mean square (RMS misfit of 0.37 cm. The preferred time-dependent afterslip mainly occurs at a depth from the surface to about 9.1 km underground and increases with time, indicating that afterslip will continue after 28 July 2010. By 334 days after the main shock, the moment released by the afterslip is 0.91 × 1018 N∙m (Mw 5.94, approximately 24.3% of that released by the coseismic slip. The preferred lower bound of the viscosity beneath the Qaidam Basin’s northern side is 1 × 1019 Pa·s, close to that beneath its southern side. This result also indicates that the viscosity structure beneath the Tibet Plateau may vary laterally.

  1. Distribution Regularities and Favorable Exploration areas of Lithologic Gas Reservoir in Sanhu Area,Qaidam Basin%柴达木盆地三湖地区岩性气藏分布规律和有利区块预测

    Institute of Scientific and Technical Information of China (English)

    郭泽清; 刘卫红; 冯刚

    2011-01-01

    柴达木盆地三湖地区第四系的形成是在第三纪末期新构造运动作用下,盆地沉积中心由西向东整体迁移的产物,在第四系中发现了世界上最大的生物气田。近年来三湖地区发现岩性气藏,将现已发现的岩性气(层)藏分为砂岩上倾尖灭型、砂岩透镜体型和物性侧向变化型3种。并提出岩性气藏分布规律是:分布于北斜坡,依附于构造背景,位于k9标志层以下,赋存于薄层砂体中,限于一定的深度范围内。根据分布规律,提出三湖地区岩性气藏的有利勘探区块,为研究区下一步进行岩性气藏勘探提供了理路依据和现实依据。%The occurrence of the Quaternary in Sanhu area of Qaidam basin, which has trapped the largest biologic gas field,is the product of migration of basin depositional center from west to east under the tectonic movements at the end of Tertiary. In recent years,lithologic gas reservoirs have been found in this area and been divided into three types including sand updip pinch-out, sand lens and sand property change in the lateral direction. The distribution regularities of lithologic gas reservoirs in the Sanhu area are summarized as distribution in the northern slope, development on the tectonic background, location below the marker bed kg,accumulation in thin sandstone and limitation to a certain depth. At last, according to the distribution regularity of lithologic gas reservoir, the authors point out favorable exploration areas of lithologic gas reservoir. This study has important theoretical and practical significances for lithologic gas reservoirs exploration in the Sanhu area of Qaidam basin.

  2. The Late Cenozoic tectonic deformation in the Western Qaidam Basin and its implications%柴达木盆地西部地区晚新生代构造变形及其意义

    Institute of Scientific and Technical Information of China (English)

    张涛; 宋春晖; 王亚东; 郑海军; 张志高; 吴松; 孟庆泉; 方小敏

    2012-01-01

    青藏高原东北缘构造变形研究是认识整个青藏高原隆升过程、机制以及印欧板块碰撞远程效应的重要途径。受控于昆仑山断裂、阿尔金断裂、祁连山断裂的柴达木盆地,新生代地层发育,较完整地记录了高原东北缘的构造变形信息。尤其柴达木盆地西部地区,构造变形强烈,晚新生代地层出露完整,是研究其晚新生代构造变形历史及驱动机制的理想地区。文中应用平衡剖面和古地磁构造旋转方法,结合最新的磁性地层年代,定量恢复该地区的构造变形历史。结果表明,在挤压应力的控制下该地区自22 Ma以来,构造变形主要表现为地层缩短与构造旋转,且其强度呈阶段性增长,具体又可划分为3个阶段:22~9.1 Ma构造活动平静期、9.1~2.65Ma构造变形相对加强期、2.65Ma以来构造变形顶峰期。研究表明,造成柴西地区地层持续缩短和顺时针旋转的关键推动力是印欧板块晚新生代的持续向北推挤、昆仑山—祁曼塔格山向柴达木盆地强烈挤压推覆以及阿尔金左旋走滑断裂大规模的复活。%The research of tectonic deformation of northeastern Tibetan Plateau is an important way to recognize the process and mechanism of the entire plateau uplift,and the remote effects of Indo-European plate collision,too.The Qaidam Basin is bounded by the Kunlun fault,Altyn Tagh fault and Qilian fault to the northwest,south and northeast,respectively,developed the thick Cenozoic sediments and have recorded the tectonic deformation information of northeastern Tibet.Especially,the western Qaidam Basin has undergone strong tectonic deformation and well exposed the Late Cenozoic strata,which is the ideal area to study the Late Cenozoic tectonic deformation history and driving mechanism.Combined with the latest high-precision paleomagnetic age,the balanced cross-section restoration and paleomagnetic structure rotation were used to reconstruct the

  3. 柴达木盆地深层地下水成矿模式及其成矿规律%The Mineralization Pattern and Laws of Deep Groundwaterin the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    王焕夫

    2001-01-01

    论述了柴达木盆地深层地下水成矿模式及其成矿规律。不仅剖析了深层地下水成矿的研究概况和化学成分的现今性状与时空分布规律;而且首次探讨了深层地下水的水文地质发育史,进行了古水文地质再造,提出了古水文地质旋回的新概念。同时,还揭示出“围压深埋型烃类运聚形成的石油(气)藏”及其“高压围限的低压区、毗邻高压区的低压区、卸压区和早熟型等4大聚油(气)区”和“高山深盆浅水蒸发型盐湖富钾卤水矿床”及其“水平分带、垂向叠加效应和水型相关”等3大成矿规律。据此,对于石油(气)藏和盐湖富钾卤水等资源开展了成矿予测,并且指出了勘查开发方向%The mineralization pattern and laws of deep groundwater in the Qaidam Basin have been expounded in this paper, the study status quo and the property and the temporal-spatial distribution of chemical components in deep groundwater have also been discussed. For the first time, the hydrogeological development history of deep groundwater has been introduced and the reconstruction of palaeo-hydrogeology has been comducted and the new concept, i.e., the palaeohydrogeological cycle, has been put forward. In addition, the oil (gas) resources formed by the deep buried hydrocarbon gathering and its four oil (gas) fields namely, the low-pressure area surrounded by the high-pressure area, the low-pressure area adjacent the high-pressure area, the pressure-decreasing area and the prematurity area as well as the potassium-abundant brine water in the salty lake formed by the evaporation of shallow ground water in the deep basin and its three mineralization laws, namely, the lateral zoning, the vertical superimposing effect and water type correlarity have been revealed. Finally, the mineralization of the oil (gas) resources and potassium-abundant brine water in the salty lake have been predicted and the exploration and

  4. Climatic and tectonic feedbacks and implications on sedimentation, tectonic deformation, and erosion circa 3.1 Ma in the Qaidam Basin, China: Evidence from magnetostratigaphy, geochemistry, and stratigraphic analysis

    Science.gov (United States)

    Heermance, R.; Pullen, A.; Kapp, P. A.; Song, P.

    2011-12-01

    Understanding the feedbacks between tectonic deformation and climate change have been the focus of recent research in the earth sciences, especially related to development of the Tibetan-Qinghai plateau. Differentiating between the causal effect of climate change or tectonic deformation on one another, however, has been hindered by the lack of detailed chronology of either mechanism at any one location. The Qaidam Basin is an internally drained basin located in the NE corner of the Tibet-Qinghai Plateau, and provides an ideal setting to interpret both the effects of climate and tectonics within inverted basin strata. Today over 50% of the basin floor is deformed by folding and faulting, and has exposed thick (>1 km) sections of pre-and-syn-tectonic Plio-Quaternary strata. We present new magnetostratigraphy from the Pliocene Shizigou and Pleistocene Qigequan Formations along the southwestern flank of an intra-basin fold and combine our new data with detailed stratigraphic and geochemical (δ18O, δ13C) analyses. Strata are characterized by shallow-lacustrine, marginal-lacustrine, and deltaic sediments that contain meter-scale, climatically controlled parasequences. Paleocurrents within the strata shift from easterly at the base to southwest for the majority of the section, but abruptly shift towards the south in the upper 200 m. Twenty-two magnetozones constrain deposition between 5.3 Ma and ~0.5 Ma and reveal that sedimentation rates were fairly constant (450±50 mm/yr) from 5.3 to 3.0 Ma, after which time rates abruptly decrease to 170±30 mm/yr. The δ18O values shift from relatively constant (avg. -6.8, range -9.6 to -4.5 VPDB) values to less negative values (avg. -1.2, range -1.2 to -2.7 VPDB) between 3.1-2.6 Ma and to widely scattered values (avg. -2.9, range -8.3 to 4.0) after ~2.6 Ma. The δ13C values remain relatively constant (avg. -4.0, range -5.7 to -1.0) until ~0.9 Ma, when the values increase to -0.3 (range -1.0 to 1.5) VPDB. The appearance of growth

  5. 柴北缘鱼卡大煤沟组七段油页岩开发价值*%Developmental Value of Oil Shale in the 7th Member of Middle Jurassic in Yuqia Area,Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    马新民; 郝海燕; 马峰; 段国禄; 程玉红

    2013-01-01

      Aimed at the 7th member of Middle Jurassic(J2d7)in Yuqia area,we undergo the solid mineral development and the comprehensive utilizationstudy. Accordingly,this study firstly discussed the tectonic background and sedimentary environment of the oil shale formed in Yuqia area based on the data from the field outcrop measured section,drilling,seismic data,sample analysis,and so on. Then economic and technological evaluations for the oil shale deposit were made according to seismic data and sample analysis. Assessment results show that the oil shale in Yuqia area is characteristic of high quality,shallow burying and big reserve. Thus it has a great potential value for development. Finally,taking into consideration developmental experiences in the world and the actual condition of Qaidam Basin,for the first time the strategy for mining and utilization of oil shale deposit in Yuqia area is proposed in this paper.%  针对柴达木盆地鱼卡地区中侏罗统大煤沟组七段(J 2 d 7)油页岩,开展了以固体矿产形式的开发、综合利用的研究。通过野外实测剖面、钻井、地震资料、样品分析,对鱼卡凹陷油页岩形成的构造背景、沉积环境进行了探讨,并对鱼卡油页岩矿产进行资源经济技术评价,认为鱼卡地区油页岩品质好,储量大,具有很好的开发价值。对其进行勘探、开发,一方面可以改善柴达木盆地当前能源短缺的局面,另一方面通过循环利用,有利于促进柴达木地区的农牧业生产。借鉴中外多年来油页岩开发经验,结合柴达木地区的实际情况,提出了地上开采和原位开采相结合,以提取页岩油、燃烧发电、燃烧取暖为主,建筑材料、有机复合肥等循环经济为辅的开发方案。

  6. 柴达木盆地西部第三系盐湖相有效生油岩的识别%Identification of Effective Source Rocks in the Tertiary Evaporate Facies in the Western Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    金强; 查明; 赵磊

    2001-01-01

    柴达木盆地西部第三系发现了储量可观的油气资源,但是总体上讲这里的生油层钙质含量高、有机质丰度低;如何识别有效生油岩,正确评价油气资源潜量,成为这里油气勘探和地球化学的首要问题。通过上、下干柴沟组生油岩的沉积特征和地球化学分析,可发现盐湖相存在许多有机质丰度较高的生油岩;利用热解和模拟实验等方法确定出有效生油岩的有机碳含量下限为0.4%。这样既为该区生油岩提供了评价标准,又找到大量有效生油岩,解决了研究区油气资源预测的基本问题。%Although there have been large volumes of oil and gas discovered from the Tertiary reservoirs in the western Qaidam basin, the source rocks have been believed as the mudstones and shales with high calcite contents and low organic carbon contents (TOC as low as 0.2%) which were deposited in the Tertiary evapo rate facies. The mudstones and shales are in great thick and distributed widely in the western Qaidam basin. In general sense, an effective source rock is ref erred to the rock with enough TOC, which expels oil when its generating oil is over a saturation in the porosity of the rock at proper buried depths or subsurf ace temperatures. If a rock with very low TOC, its generating oil could not be over the saturation for oil to be expelled out, the rock was called as ineffective source rock. Most samples analyzed by previous studies belong to the ineffec tive source rocks as their original TOC too low. Therefore, how to identify the effective source rocks is one of key aspects in petroleum resource assess ment on the Tertiary of the Qaidam basin.   By sedimentology study on the potential source rocks (dark colored mudstones and shales in the evaporate facies), the authors of this article discovered that th ere were significantly vertical changes in lithologies and TOC contents in the m udstones and shales, even in a single rhythmic

  7. 青海柴达木盆地土壤中的暗色丝孢真菌Ⅰ%Notes on soil dematiaceous hyphomycetes from the Qaidam Basin, Qinghai Province, China Ⅰ

    Institute of Scientific and Technical Information of China (English)

    王洪凤; 孔金花; 吴悦明; 张天宇

    2009-01-01

    从青海省柴达木盆地的不同生态类型地区,采集土样24份,从中分离获得暗色丝孢真菌分离物63个,经鉴定分属于14属中的25种.其中柴达木单格孢Monodictys qaidamensis和多变葡萄穗霉Stachybotrys variabilis为新种,其余为中国已报道种.文中对新种进行了拉丁文描述和图示,对23个国内己知种亦作了分布、生境、产地和海拔高度的引证.所有研究过的标本(干制培养物)与活菌种均保存在山东农业大学植物病理学标本室(HSAUP).%Sixty-three isolates of soil dematiaceous hyphomycetes belonging to 25 species in 14 genera were found from 24 soil samples in the Qaidam Basin, Qinghai province. Among them, Monodictys qaidamensis and Stachybotrys variabilis are new species. Brief descriptions and illustrations for the new taxa are given. The other 23 species previously reported from China are also listed. Dried and living cultures of all fungi studied have been deposited in the Herbarium of Sbandong Agricultural University: Plant Pathology (HSAUP).

  8. Standardization of Qilian Juniper ring-width series in the eastern margin of the Qaidam Basin%柴达木盆地东缘祁连圆柏轮宽序列标准化

    Institute of Scientific and Technical Information of China (English)

    徐岩; 邵雪梅

    2007-01-01

    Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper (Sabina przewalskii Kom.) tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, I.e. Total growth curve (TGC).The samples that contained the complete pith and reached to the growing culmination around the 40th-60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth (IRG) was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology,the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational information and TGC helps to develop more reliable tree-ring width chronology.

  9. 柴达木盆地西南区始新世—中新世事件地层研究%EOCENE-MIOCENE EVENT STRATIGRAPHY OF SOUTHWESTERN QAIDAM BASIN

    Institute of Scientific and Technical Information of China (English)

    肖传桃; 叶明; 何婷婷

    2013-01-01

    在阐述区域地质基础上,开展了研究区始新世—中新世事件地层学的研究,并建立了其事件地层系统,识别出5种事件面、8种事件带、6种事件组合和1个事件集群.事件面有隆升事件面、岩相转换事件面、洪泛事件面、生物灭绝事件面、气候转换(波动)事件面;根据地质事件的纵向发育特征,建立了暖热事件带、温凉事件带、δ18O高值事件带、δ18O低值事件带、挤压断陷事件带、走滑断陷事件带、湖盆扩张事件带和湖盆收缩事件带等,其中,暖热事件与+δ18O低值事件、温凉事件与δ18O高值事件、地壳隆升与不整合事件、气候波动与生物灭绝事件均具有成因联系,它们分别构成了一个事件组合;所有事件组合构成了该时期的事件集群.上述事件带中,挤压断陷事件带、走滑断陷与湖盆扩张事件带以及湖泊收缩事件带体现了柴达木盆地西部的演化过程,而且这个演化过程与青藏高原的隆升密不可分.由于印度大陆与欧亚大陆的碰撞、拼合与俯冲挤压,促使青藏高原不断隆升和一系列喜山运动(共四幕)的产生,同时导致了研究区始新世 中新世事件集群的发生.%Based on regional geological and stratigraphic analysis,an event stratigraphic framework of Eocene-Miocene in the Qaidam Basin has been established.Five types of event stratigraphic surface,eight event stratigraphic zones,six event stratigraphic associations,and one event stratigraphic assemblage have been recognized.Among them,event stratigraphic surfaces include the uplifting surface,lithofacies transformation surface,flooding surface,species extinction surface and climate change (fluctuation) surface.According to the spatial and temporal patterns of geological events,eight event stratigraphic zones have been established,including the warm climate zone,cool climate zone,high δ18O zone,low δ18O zone,folding and faulting zone,strike-slip fault

  10. Natural gas origins of large and medium-scale gas fields in China sedimentary basins

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China sedimentary basins present abundant natural gas resource thanks to its unique geological settings.Marine highly-matured hydrocarbon source rocks,widespread coal-measure strata and low temperature Quaternary saline strata,etc.,indicate the wide foreground of China natural gas resources. Up to now,most of the petroliferous basins have been discovered to have wholesale natural gas accumulation from Precambrian,Paleozoic,Mesozoic to Cenozoic in the east,the central,the west and the coast of China.These large and medium-scale gas reservoirs are mainly composed of hydrocarbon gas with big dry coefficient,tiny non-hydrocarbon,wide carbon isotope distribution and varying origin types,the hydrocarbon gas includes coal-formed gas,oil-formed gas,biogenic gas and inorganic gas, etc.Coal-formed gas is the main type of China natural gas resources,in particular several explored large-scale gas fields(>100 billion cubic meter)of Kela 2,Sulige and Daniudi,etc.,they all belong to coal-formed gas fields or the gas fields consisting mostly of coal-formed gas.Oil-formed gas is also abundant in China marine basins,for example marine natural gas of Sichuan Basin generated from crude oil cracking gas.Primary and secondary biogenic gas fields were discovered respectively in the Qaidam Basin and Western Slope of Songliao Basin.In addition,inorganic gases are mainly distributed in the eastern China,in particular the Songliao Basin with abundant carbon dioxide accumulation,indicating that the eastern China present large exploration potential of inorganic gas.

  11. 柴达木盆地大浪滩梁-ZK02孔的磁性地层及其古环境研究%Magnetostratigraphy of Liang-ZK02 Borehole in Dalangtan, Qaidam Basin and Its Paleoenvironmental Significance

    Institute of Scientific and Technical Information of China (English)

    秦永鹏; 侯献华; 郑绵平; 杨振宇; 李洪普; 施林峰

    2012-01-01

    对柴达木盆地西部大浪滩盐湖梁-ZK02孔岩芯进行详细的磁性地层研究,确定钻孔岩芯的B-M界线位于315m,Jaramillo位于405~430m,Olduvai位于772 ~ 816m.在磁性年代学框架基础上,以蒸发岩沉积序列作为主要依据,结合碎屑岩变化以及孢粉分析,认为该地区在第四纪发生过三次较大的沉积环境变化,分别发生在2.5~2.2Ma,1.2~0.7Ma与0.4Ma.青藏高原第四纪的隆升是造成上述三次变化的主要原因,其中早更新世末—中更新世早期的隆升对柴达木盆地的气候影响较大,导致柴达术盆地的气候由温凉湿润转换为寒冷干旱.高原隆升引起的气候干旱并非简单的逐渐加剧,而是早更新世末期以来,气候湿润期表现得更为湿润,这种现象可能由高原隆升增加了夏季风的强度导致,冰川和积雪面积的增大也起到了叠加效应.%A detailed magnetostratigraphic investigation has been carried out on a 1000-m-thick sequence of Liang-ZK02 Borehole in Dalangtan, northwest of the Qaidam Basin. Magnetostratigraphic results show that the B-M boundary of borehole is located in 315m, Jaramillo subchron and Olduvai subchron are located in 405 ~430m and 772 ~816m, respectively. Three large environmental changes in Quaternary, occurred around 2.5 ~ 2. 2Ma, 1. 2 ~0. 7Ma and 0.4Ma, are identified based on integrated analysis of evaporites, clastic rock and sporo-pollen record. The uplift of Xizang ( Tibetan) Plateau was probably the main reason for these environmental changes, paleoclimate of Qaidam Basin transferred from cool, wet climate to cold, dry climate in the end of Early Pleistocene to early Middle Pleistocene because of the uplift of the Xizang( Tibetan) Plateau. The trend of aridification caused by uplift is not intensified gradually, the climate became wetter in humid period since the end of Early Pleistocene, which might result from intensified strength of summer monsoon caused through uplift of Xizang

  12. Clay Characteristics of Tertiary Rocks with Parallel Level Fractures in Western Qaidam Basin%柴西地区第三系发育平行层面缝岩石的粘土矿物特征

    Institute of Scientific and Technical Information of China (English)

    畅斌; 张金功

    2013-01-01

    Core sample and microscopic fluorescent observation, SEM and X-ray diffraction research showed that there are two types of clay minerals combination from top to bottom of parallel level fractures, the Tertiary in western Qaidam basin: I/S+I+CH+(K)→I+CH+I/S+C/S+(K). Contents of clay minerals lie between 7% -27%, and tend to decrease gradually with increasing depth. Organo clay complexe is the consequence of abnormal high fluid pressure, reduction environment, organic matter, passage system of fractures and hydrodynamic force.%柴西地区第三系地层中多发育平行层面缝,通过岩心及荧光显微镜观察,并借助扫描电子显微镜(SEM)和X射线衍射分析(XRD),确定了柴西地区第三系发育平行层面缝岩石自上而下存在2种粘土矿物组合:伊/蒙间层+伊利石+绿泥石+(高岭石)→伊利石+绿泥石+伊/蒙间层+绿/蒙间层+(高岭石),粘土矿物占全岩矿物比例介于7%~27%之间,粘土矿物吸附并保存了有机质,这是异常高压、强还原环境、有机质及平行层面缝优势输导体系和强水动力作用多种因素叠加影响的结果.

  13. Crude Production Tops 2 Million Tons at Qinghai Oil Field

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ The crude oil output of Qinghai Oil Field in Qaidam basin of the northwestern China's Qinghai Province topped two million tons at the end of 2000.This is the first time that the annual crude oil output of the oilfield has exceeded two millions, according to Huang Ligong, general manager of Qinghai Oil Field under PetroChina.

  14. 柴达木盆地西部地区新生代演化特征与青藏高原隆升%Cenozoic Uplift of the Tibetan Plateau: Evidence from tectonic-sedimentary evolution of the Western Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    王亚东; 张涛; 迟云平; 刘艳蕊; 张志高; 李仕远; 方小敏; 张跃中

    2011-01-01

    通过对柴达木盆地西部地区(柴西地区)地震剖面构造-沉积相演化的分析,结合基底岩性及区域构造运动历史,重建了柴西地区新生代构造-沉积动态演化框架.柴西地区新生代以来一直处在印欧板块碰撞所引起的青藏高原阶段性隆升的挤压构造背景下,经历了两大构造变形期:第一变形期主要发育在古近纪,变形高峰在下干柴沟组上段,第二变形期发育在新近纪-第四纪,变形强度日益加剧.剖面沉积相的变化体现柴西地区经历了水进-静水沉降-水退的过程,平面沉积相演变是沉积中心受构造运动控制的直接结果;受构造演化控制柴西地区以Ⅺ号(油狮断裂)和油北断裂为分界线,由南至北地表形态表现为3种不同样式:柴西南区断裂发育,柴西中部为英雄岭新生造山带,柴西北区主要发育冲断褶皱.柴西地区构造-沉积演化特征是对青藏高原阶隆升的响应,同时记录了青藏高原向北间歇性蔓延生长的过程.%on the basis of the analysis of structure and sedimentary evolution of the seismic section in Western Qaidam Basin and combining the basement lithology, faults distribution and history of tectonic movement, we reconstructed the dynamical evolution framework of structure and sedimentation of Western Qaidam Basin during the Cenozoic. Our results suggested that Western Qaidam Basin was under the compression tectonicbackground of the Tibetan Plateau uplift caused by the collision of India and Eurasia in the Cenozoic and underwent two violent periods of tectonic deformation. The Western Qaidam Basin had undergone two periods of tectonic deformation. The first ocurred in the Paleocene, and reached the peak at the E23; the second was in the Neocene-Quaternary, and the deformation intensified rapidly. The forces transmitted from the south to the north,while the tectonic deformation spread from the west to the east, which indicated that the thrust of the

  15. 柴北缘含煤区地层测井物性特征分析%Strata Well Logging Characteristic Analysis of Coal-bearing Area on North Margin of Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    潘语录

    2011-01-01

    Taking the Iqe coalfield on the north margin of the Qaidam Basin, canied out analysis of well logging response characteristics of various lithologic rocks in coal-bearing strata. The analysis has considered that the geophysical characters of the area belong to "simple and easy to distinguish" type, that is to say the physical property of coal seams and rocks has rather distinct differences, different lithologic rocks have obvious different characters on gamma-gamma, gamma-ray and resistivity logging traces. Based on logging (races characteristic variation amplitudes, high or low crest values can distinguish and correlate coal seams and rocks effectively. On the practical logging interpretation result basis, carried out logging trace combination characteristics description of marker bed sectors of upper Jurassic Hongshuigou and Caishib'ng formations, middle-lower Jurassic Dameigou Formation shale, upper and lower coal-bearing members.%以柴达木盆地北缘的鱼卡煤田为例,对含煤地层中的各种岩性的测井响应特征进行分析,认为该区的地球物理特征属“简单易区别”型,即煤岩层的物性差异较大,物性条件较好,不同岩性在伽马-伽马、自然伽马、电阻率等测井曲线上的特征明显,根据曲线的变化幅度、峰值高低等曲线特征,可有效进行煤岩层划分与对比.根据实际测井解释成果,对侏罗系上统红水沟组、采石岭组、侏罗系中-下统大煤沟组的页岩段、上含煤段及下含煤段等标志层段的测井曲线组合特征进行了描述.

  16. 柴达木盆地不同盐生境下黑果枸杞形态结构比较%Morphological Structure Comparison of Lycium ruthenium at Different Salt Habitats in Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    辛菊平; 朱春云

    2015-01-01

    对柴达木盆地5个盐生境的黑果枸杞进行了形态结构比较,探讨黑果枸杞为适应环境的响应。结果表明,不同盐分生境植株形态特征差异明显。全盐含量高、 K+含量高、 Cl-/SO42-毫克当量比大的氯化物-硫酸盐型土壤中植株高大,冠幅小而紧凑,叶片长条形,横切面圆形,高度肉质化,叶肉栅栏组织形成“环栅型”结构,叶脉不明显,无叶柄,枝刺尖利、坚硬;全盐含量低、 Na+含量高、 Cl-/SO42-毫克当量比值小的硫酸盐-氯化物型土壤中植株形态反之。但人工栽培后, K+为主, Cl-/SO42-毫克当量比大的硫酸盐-氯化物型土壤中植株较高,叶变为披针形,栅栏组织呈条形,叶脉明显,具短小叶柄,枝刺变长、变软。%For understanding the morphological structure changes of Lycium ruthenium to adapt to the environment , the plant morphological structure and soil salt of L.ruthenium which grew at 5 different environment was studied in Qaidam Basin.The results showed that the plant morphological characteristics under different saline environment were significantly different.The high salt content, high content of K+, Cl-/SO4 2-mEq ratio and chloride-sulfate in the soil plant tall, the crown was small and compact, the leaf shape was long and thin strip, the transver sesection was circular , leaves became highly succulent , palisade tissue in mesophyll was “ring fence” type structure , leaf veins were not obviously, no petiole, branches were sharp, hard branch spines; Low salt content, high content of Na+and small Cl-/SO4 2-mEq ratio, type of sulfate-chloride in soil , the plant was contrary to the above.How-ever, after artificial cultivation, in high content of K+, high Cl-/SO4 2-mEq ratio, type of sulfate-chloride in soil, the plant was higher, lanceolate leaf with white short nap, normal palisade tissue structure with obvious veins, short petiole, longer and

  17. 柴达木盆地西部古近系储层裂缝有效性的影响因素%Influence Factors on Fracture Validity of the Paleogene Reservoir,Western Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    曾联波; 巩磊; 祖克威; 唐小梅; 王铁成; 王成刚; 许文国

    2012-01-01

    The Paleogene saline-facies fracture marlstone is one of the important reservoir types in the western Qaidam Basin. There are four kinds of fractures developed in the reservoir: shear fracture, tensional fracture, sliding fracture and diagenesis fracture. Fractures are generally filled with calcite, gypsum and glauberite. The fracture validity is very important to reservoir evaluation. Effective fractures not only provide storage spaces and channels for fluid flow, but also determine enrichment rule and output potential of oil and gas. The fracture validity is controlled mainly by formation time, dissolution, uplift and denudation since the Quaternary, abnormal fluid high pressure, distribution of gypsum and salt beds, and fault activity. Late fractures are more effective than early fractures. Dissolution can obviously increase the fracture validity. Since the Quaternary, tectonic uplift and denudation, and abnormal fluid high pressure make filled fractures reopen, improving the fracture validity. The farther fractures distribute from gypsum and salt beds, the better the validity. The fracture validity has no close relation with current Earth stress direction but is mainly influenced by fault activities, and fractures parallel to main faults are of the best validity.%古近系盐湖相裂缝性泥灰岩储层是柴达木盆地西部地区的重要储层类型,储层中发育剪切裂缝、纵张裂缝、顺层滑动裂缝和成岩裂缝4种类型.裂缝普遍被方解石、石膏或钙芒硝等充填,裂缝的有效性对储层评价十分重要.有效裂缝不仅提供了储层的重要储集空间和主要渗流通道,还决定了油气的富集规律和储层的潜在生产能力.裂缝的有效性主要受裂缝形成时间、溶蚀作用、第四纪以来的构造抬升剥蚀作用、异常流体高压作用、膏盐层分布和断层的活动性等因素控制.晚期形成的裂缝有效性更好;溶蚀作用可明显地增加裂缝的有效性;第四纪以

  18. Reservoir Evaluation on Mixing Deposit of Shizigou Formation in Xiaoliangshan,Northwest of Qaidam Basin%柴西北小梁山地区狮子沟组混积岩储层评价

    Institute of Scientific and Technical Information of China (English)

    司马立强; 杨毅; 吴丰; 姚军朋; 赵为永

    2014-01-01

    从有利于混积岩储层评价出发,将小梁山狮子沟组(N32)混积岩简化归类为泥质混积岩、砂质混积岩和碳酸盐混积岩,在此基础上根据铸体薄片、物性、孔隙结构等岩心分析数据和测井资料,对柴达木盆地西北部小梁山地区中浅层N32混积岩进行综合研究:N32混积岩岩石结构复杂、类型多样,储层储集空间以原生的粒间孔和微孔隙为主,呈中高孔低渗的特征,排驱压力、中值压力较高,孔喉半径较小,孔隙结构较差;储层质量受沉积相和成岩作用的综合影响,砂坪微相是最主要的有利储集相带,压实作用是储层物性的主要影响因素;根据物性和压汞等参数将N32储层评价为3类,其中Ⅰ、Ⅱ类储层在目前的技术条件下是研究区增储上产的首选储层。%The mixing deposit of N32 in Xiaoliangshan region is simply classed as argillaceous mixing deposit, arenaceous mixing deposit and carbonate mixing deposit for reservoir evaluation.On this basis,combining the data of core analysis,the casting thin sections,porosity and permeability analysis,mercury injection test and log,this paper investigates the mixing deposit reservoir of Shizigou Formation in Xiaoliangshan,northwest of Qaidam Basin:The mixing deposit has complex rock structure and various rock type.The pore space of reser-voir mainly includes the primary intergranular pores and micropores.The reservoir properties are mainly medi-um-high porosity and low permeability,high displacement and saturation median point pressure,small pore throat radius.The pore structure are generally poor.The sedimentation and diagenesis have played important roles in evolution of resevoir.The sand flat microfacies is the main favorable reservoir facies.Compaction is the major factor that has influence on the reservoir physical property.N32 are divided into three types according to parameters like physical property,capillary pressure and so

  19. Analysis of Long-Term Changes in Temperature and Precipitation and Their Relationships with Water Resources in the Qaidam Basin in China%柴达木盆地气温降水的长序列变化及与水资源关系

    Institute of Scientific and Technical Information of China (English)

    傅小城; 王芳; 王浩; 段水强

    2011-01-01

    根据柴达木盆地8个气象观测站点1960年-2009年共50年的逐月平均气温及降水量资料,综合运用线性趋势分析及Mann-Kendall趋势检验等气象统计分析方法对柴达木盆地气温及降水的变化趋势进行了分析.结果表明在过去的50年里,柴达木盆地经历了明显的升温过程,且增温幅度越来越大,特别是进入20世纪90年代,总的升温幅度在0.5℃/10a左右,远大于同期全球的升温幅度;柴达木盆地降水也略有上升,变化幅度6.2mm/10a左右.从空间分布上看,柴达木盆地气温增幅从东到西逐渐增高,而降水倾向率则逐渐减小.季节分布上,盆地内冬季的气温升温幅度最为明显,增温幅度达0.72℃/10a左右,降水倾向率则夏季最大,达3.4mm/10a.累积距平曲线及Mann-Kendall趋势突变检验综合分析表明,柴达木盆地气温在20世纪80年代有一个明显的增温过程,增温起点在1987年左右.气温、降水的变化也在一定程度上影响到水资源量的变化,相关分析表明,地表水资源量与降水呈显著相关关系,但与气温关系不明显.另外,上一年降水也对地表水资源量有一定的影响.%Global climate change induced by increasing emissions of greenhouse gasses is expected to have a considerable impact on the global hydrologic cycle. Along with global warming, temperature and rainfall varied across China, especially in northwestern China. The Qaidam basin, an important part of northwestern China, is very sensitive to climate change. In this paper, trends in temperature and rainfall in the Qaidam basin were derived by the linear trend analysis and Mann-Kendall trend test based on monthly meteorological data at 8 weather stations during the period 1960-2009. The Mann-Kendall abrupt test was also used to detect the abrupt changes of mean annual temperature and precipitation. The relationships between surface water resources and precipitations were comprehensively investigated

  20. 柴达木盆地北缘南八仙构造油气运聚成藏机理与模式探讨%Discussion of the Mode and Mechanism of Oil and Gas Accumulation in the Nanbaxian Pool in the North of the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    李凤君; 罗群; 陈淑兰; 刘运宏; 田丰华

    2005-01-01

    Because of the difference of oil and gas accumulation condition between the hanging wall and the footwall of a fault, there is a peculiar accumulation mechanism that oil and gas mainly exists in the hanging wall of the basement fault, but in the footwall of the shallow detachment fault in the Nanbaxian pool. The oil and gas of the Nanbaxian pool came from the mature Jurassic hydrocarbon source rock of the Yibei depression located at the south of the Nanbaxian pool. Firstly, the oil and gas accumulated in the traps of the hanging wall of the basement fault by way of the unconformity and the basement faults, and turned into some primary deep pools; and then, the shallow detachment fault that formed in the later tectonic movement broke into the deep primary pools, which caused the oil and gas migration upwards along the basement faults and the shallow detachment faults and the evolvement into some secondary oil and gas pools later. The history of the Nanbaxian oil and gas accumulation can be summarized successively as the syndepositional upheaval controlled by faults; single hydrocarbon source rock; unconformities and faults as migration channels; buoyancy, overpressure and tectonic stress as dynamic forces; multistage migration and accumulation of oil and gas; and finally an overlapped double-floor pattern of oil and gas accumulation. The most important explorative targets in the north of the Qaidam Basin are traps connected with the primary pools in the footwall by shallow detachment faults.

  1. Analyzing and modeling the coverage of vegetation in the Qaidam Basin of China:The role of spatial autocorrelation%柴达木盆地植被覆盖度的分析与模拟——空间自相关方法的运用

    Institute of Scientific and Technical Information of China (English)

    ZHU Wenbin; JIA Shaofeng; L(U) Aifeng; YAN Tingting

    2012-01-01

    @@%Relationship between vegetation and environmental factors has always been a major topic in ecology,but it has also been an important way to reveal vegetation's dynamic response to and feedback effects on climate change.For the special geographical location and climatic characteristics of the Qaidam Basin,with the support of traditional and remote sensing data,in this paper a vegetation coverage model was established.The quantitative prediction of vegetation coverage by five environmental factors was initially realized through multiple stepwise regression (MSR) models.However,there is significant multicollinearity among these five environmental factors,which reduces the performance of the MSR model.Then through the introduction of the Moran Index,an indicator that reflects the spatial autocorrelation of vegetation distribution,only two variables of average annual rainfall and local Moran Index were used in the final establishment of the vegetation coverage model.The results show that there is significant spatial autocorrelation in the distribution of vegetation.The role of spatial autocorrelation in the establishment of vegetation coverage model has not only improved the model fitting R2 from 0.608 to 0.656,but also removed the multicollinearity among independents.

  2. From oceanic subduction to continental collision: An overview of HP-UHP metamorphic rocks in the North Qaidam UHP belt, NW China

    Science.gov (United States)

    Zhang, Guibin; Zhang, Lifei; Christy, Andrew G.

    2013-02-01

    The North Qaidam UHPM belt is unique among "continental type" subduction zones in showing well-preserved subducted oceanic relics that predate continental subduction and collision. We review petrologic, thermobarometric, geochemical and geochronological studies for the Yuka, Luliang Shan, Xitieshan and Dulan terranes in this belt. UHP conditions are demonstrated by coesite inclusions in eclogite and country gneiss, and diamond inclusions from garnet peridotite. The relict subducted oceanic lithology crops out in the Shaliuhe cross-section in Dulan terrane; it originated as the floor of a Paleo-Qilian Ocean that existed between Qaidam and Qilian blocks before the early Ordovician. Whereas most eclogites of this belt are derived from mafic rocks of either a Neoproterozoic continental rift or incipient oceanic basin setting, which were subducted along with continental rocks in the early Paleozoic. The data, especially the two protolith sources for eclogites, demonstrate tectonic evolution of the North Qaidam UHPM belt from oceanic subduction to continental collision.

  3. MDD法和裂变径迹法相结合模拟样品的低温热历史——以柴达木盆地北缘赛什腾山中新生代构造演化为例%MODELING THERMAL HISTORY DURING LOW TEMPERATURE BY K-FELDSPAR MDD AND FISSION TRACK:EXAMPLE FROM MESO-CENOZOIC TECTONIC EVOLUTION IN SAISHITENGSHAN IN THE NORTHERN MARGIN OF QAIDAM BASIN

    Institute of Scientific and Technical Information of China (English)

    万景林; 郑德文; 郑文俊; 王伟涛

    2011-01-01

    MDD法和裂变径迹法是2种最常用的低温热年代学方法.通过对它们的测试结果的模拟,揭示出样品经历的热历史,可以有效地延伸这2种方法的研究范围.但是由于模拟的多解性,使得如何制约模拟过程,获得合理的模拟结果显得尤为重要.通过柴达木盆地北缘的模拟过程,展示了模拟中可能存在的问题及提高模拟结果的方法.同时揭示了柴达木盆地北缘中新生代可能存在的3次冷却事件,分别发生在距今约130~150、30~40和5~10Ma.%K-Feldspar MDD( Multiple Diffusion Domain)and fission track are two commonly-used methods in low closure temperature thermal chronometry. By modeling both the feldspar 39Ar/40Ar data and the fission track age and track-length data, the thermal history that sample underwent can be revealed and the effective temperature range of both feldspar 39Ar/40Ar method and fission track method is extended.Because of the multiple resolution of modeling, it is important to restrict the modeling process to gain a reasonable result, though it seems difficult. The possible problem in modeling thermal history is presented in this paper, and the helpful method that can be used to improve the result is illustrated by the sample collected along Saishitengshan in the northern margin of Qaidam Basin. Three rapid cooling events, occurring at 130 ~ 150Ma,30 ~ 40Ma and 5 ~ 10Ma respectively, in northern margin of Qaidam Basin are revealed by feldspar MDD method and fission track method.

  4. Age and duration of eclogite-facies metamorphism, North Qaidam HP/UHP terrane, Western China

    Science.gov (United States)

    Mattinson, C.G.; Wooden, J.L.; Liou, J.G.; Bird, D.K.; Wu, C.L.

    2006-01-01

    Amphibolite-facies para-and orthogneisses near Dulan, at the southeast end of the North Qaidam terrane, enclose minor eclogite and peridotite which record ultra-high pressure (UHP) metamorphism associated with the Early Paleozoic continental collision of the Qilian and Qaidam microplates. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. SHRIMP-RG U-Pb and REE analyses of zircons from four eclogites yield weighted mean ages of 449 to 422 Ma, and REE patterns (flat HREE, no Eu anomaly) and inclusions of garnet, omphacite, and rutile indicate these ages record eclogite-facies metamorphism. The coherent field relations of these samples, and the similar range of individual ages in each sample suggests that the ???25 m.y. age range reflects the duration of eclogite-facies conditions in the studied samples. Analyses from zircon cores in one sample yield scattered 433 to 474 Ma ages, reflecting partial overlap on rims, and constrain the minimum age of eclogite protolith crystallization. Inclusions of Th + REE-rich epidote, and zircon REE patterns are consistent with prograde metamorphic growth. In the Lu??liang Shan, approximately 350 km northwest in the North Qaidam terrane, ages interpreted to record eclogite-facies metamorphism of eclogite and garnet peridotite are as old as 495 Ma and as young as 414 Ma, which suggests that processes responsible for extended high-pressure residence are not restricted to the Dulan region. Evidence of prolonged eclogite-facies metamorphism in HP/UHP localities in the Northeast Greenland eclogite province, the Western Gneiss Region of Norway, and the western Alps suggests that long eclogite-facies residence may be globally significant in continental subduction/collision zones.

  5. Stress Field and Seismicity in the Basin of Mexico

    Science.gov (United States)

    Huesca-Perez, E.; Quintanar, L.; Garcia-Palomo, A.

    2007-12-01

    Mexico City is located in the basin of Mexico, inside the so called Trans-Mexican Volcanic Belt. The region in general and the basin in particular, is characterized by local low magnitude seismicity (Mc Chalco and 3)- Juchitepec - Milpa Alta outside Mexico City; the rest of the basin presents lower seismic activity. We recorded and located 336 earthquakes with digital seismograms between 1996 and 2007. From them, just 23 focal mechanisms could be evaluated because of low magnitude that creates recording problems in the seismological networks and high frequency background noise. The focal mechanisms are mainly strike-slip and dip-slip (normal) faulting. We used three different techniques (when possible) to calculate the focal mechanisms: simple and composite first motion focal mechanism, Hash's S/P amplitude rate focal mechanism and time domain moment tensor inversion using broadband three components seismograms. The final goal is to find the local and regional stress field for the whole basin.

  6. Numerical representation of rainfall field in the Yarmouk River Basin

    Science.gov (United States)

    Shentsis, Isabella; Inbar, Nimrod; Magri, Fabien; Rosenthal, Eliyahu

    2017-04-01

    Rainfall is the decisive factors in evaluating the water balance of river basins and aquifers. Accepted methods rely on interpolation and extrapolation of gauged rain to regular grid with high dependence on the density and regularity of network, considering the relief complexity. We propose an alternative method that makes up to those restrictions by taking into account additional physical features of the rain field. The method applies to areas with (i) complex plain- and mountainous topography, which means inhomogeneity of the rainfall field and (ii) non-uniform distribution of a rain gauge network with partial lack of observations. The rain model is implemented in two steps: 1. Study of the rainfall field, based on the climatic data (mean annual precipitation), its description by the function of elevation and other factors, and estimation of model parameters (normalized coefficients of the Taylor series); 2. Estimation of rainfall in each historical year using the available data (less complete and irregular versus climatic data) as well as the a-priori known parameters (by the basic hypothesis on inter-annual stability of the model parameters). The proposed method was developed by Shentsis (1990) for hydrological forecasting in Central Asia and was later adapted to the Lake Kinneret Basin. Here this model (the first step) is applied to the Yarmouk River Basin. The Yarmouk River is the largest tributary of the Jordan River. Its transboundary basin (6,833 sq. km) extends over Syria (5,257 sq.km), Jordan (1,379 sq. km) and Israel (197 sq. km). Altitude varies from 1800 m (and more) to -235 m asl. The total number of rain stations in use is 36 (17 in Syria, 19 in Jordan). There is evidently lack and non-uniform distribution of a rain gauge network in Syria. The Yarmouk Basin was divided into five regions considering typical relationship between mean annual rain and elevation for each region. Generally, the borders of regions correspond to the common topographic

  7. Development of Moxi Gas Field, Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    Xiong Yiming

    1995-01-01

    @@ Moxi Gas Field is located in south of Suining City in Sichuan Province, covering Jurassic and Triassic oil and gas reservoirs. The major one is Tr1 1reservoir of Triassic Leikoupo (Tr) system and the other two are Jia2 (Tc2) reservoir of Triassic Jia Lingjiang (Tc) system and Xiangxi (Th) reservoir.The Tr1 1 reservoir was discovered in early 1987 and datailed exploration was completed in June, 1988.

  8. Découverte de coésite dans la ceinture métamorphique UHP d'âge Paléozoïque inférieur du Nord-Qaidam, Chine nord-occidentale

    Science.gov (United States)

    Yang, Jingsui; Xu, Zhiqin; Song, Shuguang; Zhang, Jianxin; Wu, Cailai; Shi, Rendeng; Li, Haibing; Brunel, Maurice

    2001-12-01

    Coesite and graphite were discovered as inclusions in zircon separates from pelitic gneiss associated with a large eclogite body in the North Qaidam UHP terrane. This finding suggests UHP metamorphism at pressures below the diamond stability field. This supports previous indirect UHP evidences, such as polycrystalline quartz inclusions in eclogitic garnet, quartz lamellae in omphacite and P- T estimates for both eclogite and garnet peridotite. The U/Pb and Sm/Nd isotopic ages from the North Qaidam eclogite indicated that continental subduction occurred in Early Palaeozoic, most probably in relation with the collision between the Sino-Korean and Yangtze plates.

  9. 柴达木盆地表土与大气降尘粒度Weibull组成及其环境意义%Grain-size Weibull Composition of Surface Dust Deposits and Atmospheric Dustfall, and Their Environmental Implications in Qaidam Basin, China

    Institute of Scientific and Technical Information of China (English)

    肖舜; 周爱锋; 黄小忠; 金明; 孙东怀; 陈发虎

    2012-01-01

    aeolian dust, climate and ocean biogeochemistry. In comparison, the coarse grains are generally transported by sur- face wind in short-duration suspension episodes, and they accumulate in the adjacent downwind areas to form loess. In the paper, we summarize the grain-size distribution patterns of aeolian dust deposits from different sedimentary environments. Results show that there are lower content of fine and ultrafine components in surface deposits, higher content of coarse component in dust storm samples, and high content of fine compo- nent in dust-trapped lake ice column from the Sugan Lake in northern Qaidam Basin. There are similar grain-size distribution patterns in annual dustfall, seasonal dustfall and dustfall during duststorm events, which indicate that annual dusffall and seasonal dustfall are mainly contributed by regional duststorm events. In summer, the content of fine component in dustfall is slightly higher, which should be due to more precipi- tation. Detailed examination on the fine and the ultrafine components of annual dustfall, seasonal dustfall and duststorm samples suggests that dust particles originate not only from dustfall during duststorm events, but also from atmospheric dust loadings associated with westerly circulation. In addition, the fine component of dust trapped in lake ice column can be regarded a paleoclimatic proxy for winter wind regime responding to Siberian-Mongolian High Pressure System.

  10. Reserve Growth in Oil Fields of West Siberian Basin, Russia

    Science.gov (United States)

    Verma, Mahendra K.; Ulmishek, Gregory F.

    2006-01-01

    Although reserve (or field) growth has proven to be an important factor contributing to new reserves in mature petroleum basins, it is still a poorly understood phenomenon. Limited studies show that the magnitude of reserve growth is controlled by several major factors, including (1) the reserve booking and reporting requirements in each country, (2) improvements in reservoir characterization and simulation, (3) application of enhanced oil recovery techniques, and (4) the discovery of new and extensions of known pools in discovered fields. Various combinations of these factors can affect the estimates of proven reserves in particular fields and may dictate repeated estimations of reserves during a field's life. This study explores the reserve growth in the 42 largest oil fields in the West Siberian Basin, which contain about 55 percent of the basin's total oil reserves. The West Siberian Basin occupies a vast swampy plain between the Ural Mountains and the Yenisey River, and extends offshore into the Kara Sea; it is the richest petroleum province in Russia. About 600 oil and gas fields with original reserves of 144 billion barrels of oil (BBO) and more than 1,200 trillion cubic feet of gas (TCFG) have been discovered. The principal oil reserves and most of the oil fields are in the southern half of the basin, whereas the northern half contains mainly gas reserves. Sedimentary strata in the basin consist of Upper Triassic through Tertiary clastic rocks. Most oil is produced from Neocomian (Lower Cretaceous) marine to deltaic sandstone reservoirs, although substantial oil reserves are also in the marine Upper Jurassic and continental to paralic Lower to Middle Jurassic sequences. The majority of oil fields are in structural traps, which are gentle, platform-type anticlines with closures ranging from several tens of meters to as much as 150 meters (490 feet). Fields producing from stratigraphic traps are generally smaller except for the giant Talin field which

  11. Structural investigations of Great Basin geothermal fields: Applications and implications

    Energy Technology Data Exchange (ETDEWEB)

    Faulds, James E [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Hinz, Nicholas H. [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Coolbaugh, Mark F [Great Basin Center for Geothermal Energy, Univ. of Nevada, Reno, NV (United States)

    2010-11-01

    Because fractures and faults are commonly the primary pathway for deeply circulating hydrothermal fluids, structural studies are critical to assessing geothermal systems and selecting drilling targets for geothermal wells. Important tools for structural analysis include detailed geologic mapping, kinematic analysis of faults, and estimations of stress orientations. Structural assessments are especially useful for evaluating geothermal fields in the Great Basin of the western USA, where regional extension and transtension combine with high heat flow to generate abundant geothermal activity in regions having little recent volcanic activity. The northwestern Great Basin is one of the most geothermally active areas in the USA. The prolific geothermal activity is probably due to enhanced dilation on N- to NNE-striking normal faults induced by a transfer of NW-directed dextral shear from the Walker Lane to NW-directed extension. Analysis of several geothermal fields suggests that most systems occupy discrete steps in normal fault zones or lie in belts of intersecting, overlapping, and/or terminating faults. Most fields are associated with steeply dipping faults and, in many cases, with Quaternary faults. The structural settings favoring geothermal activity are characterized by subvertical conduits of highly fractured rock along fault zones oriented approximately perpendicular to the WNW-trending least principal stress. Features indicative of these settings that may be helpful in guiding exploration for geothermal resources include major steps in normal faults, interbasinal highs, groups of relatively low discontinuous ridges, and lateral jogs or terminations of mountain ranges.

  12. Geological study of Guafita field reservoirs, Apure basin, southwestern Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Moya, E.; Abud, J.; Hernandez, J.

    1989-03-01

    The medium-grade oil reservoirs of the Guafita field, Apure basin, southwestern Venezuela, represent the northeastern extension of the La Yuca-Cano Limon fields of Colombia. A detailed integrated reservoir study is being carried out in Guafita in order to define the geological model and to improve its development plan. The stratigraphic sequence of interest in the southern block of the Guafita field contains approximately 600 ft of sediments of Cretaceous and Oligocene-Miocene ages (Quevedo Member of the Navay and Guafita Formations, respectively). Fifteen prospective intervals, with approximately 150 ft of net oil sand, have been defined within this sequence by detailed correlation in the Colombian fields and four have been defined in the Quevedo Member. Lower delta-plain and delta-front depositional environments have been recognized from core studies in the Tertiary sediments. A combination of both structural and stratigraphic traps controls the hydrocarbon accumulations in the Guafita field, and at least two sealing shale regional markers have been defined. As a preliminary result of the approach of defining reservoir geometry and mapping each major sand body separately, the proven reserves of the Guafita field will decrease by approximately 12%. The possibility of fluid communication with the Colombian fields through the small-displacement riddle faults was established by means of juxtaposition of sand bodies.

  13. Tectonic evolution of Tethyan tectonic field, formation of Northern Margin basin and explorative perspective of natural gas in Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Analyzing the characteristics of the Tethyan tectonic field, the authors think that the Tethyan tectonic field underwent three evolutional stages: closing of Paleo-Tethys and rifting of Neo-Tethys from early Permian to late Triassic, subduction of Neo-Tethys and collision between the Indian plate and the Eurasia plate from Jurassic to early of low Tertiary, and collision between the Arab plate and the Eurasia plate and the A-type subduction of Indian plate from late of low Tertiary to the present. Combining the evolution of the Tethyan orogenic belt with the characteristics of the Northern Margin basin, it is suggested that the sedimentary and tectonic characteristics and types of the Northern Mar-gin basin are controlled by the formation and evolution of the Tethyan orogenic belt and the ingression of Tethys. The evolution of Northern Margin basin can be divided into three development stages: back-arc foreland basin from late Permian to Triassic, the back-arc fault subsidence and depression from Jurassic to the early of low Tertiary, and the reactive foreland basin from the late of low Tertiary to the present. The Northern Margin basin in the Tethyan tectonic field is an important region for natural gas accumulation, and the Tarim Basin is a part of this region.

  14. Third One-million-ton Oil Field in Junggar Basin Will Come into Being

    Institute of Scientific and Technical Information of China (English)

    Tian Jun; Li Songguo

    2002-01-01

    @@ PetroChina Xinjiang Oil FieldCompany is accelerating its efforts for construction of the third 1-million-ton oil field in Junggar basin - Luliang oil field located in the hinterland of the basin, which was found in 2000.

  15. Geochronology and tectonic significance of Middle Proterozoic granitic orthogneiss, North Qaidam HP/UHP terrane, Western China

    Science.gov (United States)

    Mattinson, C.G.; Wooden, J.L.; Liou, J.G.; Bird, D.K.; Wu, C.L.

    2006-01-01

    Amphibolite-facies para- and orthogneisses near Dulan, in the southeast part of the North Qaidam terrane, enclose minor ultra-high pressure (UHP) eclogite and peridotite. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. Ion microprobe U-Pb and REE analyses of zircons from two granitic orthogneisses indicate magmatic crystallization at 927 ?? Ma and 921 ?? 7 Ma. Zircon rims in one of these samples yield younger ages (397-618 Ma) compatible with partial zircon recrystallization during in-situ Ordovician-Silurian eclogite-facies metamorphism previously determined from eclogite and paragneiss in this area. The similarity between a 2496 ?? 18 Ma xenocrystic core and 2.4-2.5 Ga zircon cores in the surrounding paragneiss suggests that the granites intruded the sediments or that the granite is a melt of the older basement which supplied detritus to the sediments. The magmatic ages of the granitic orthogneisses are similar to 920-930 Ma ages of (meta)granitoids described further northwest in the North Qaidam terrane and its correlative west of the Altyn Tagh fault, suggesting that these areas formed a coherent block prior to widespread Mid Proterozoic granitic magmatism. ?? Springer-Verlag 2006.

  16. Petroleum system of the Cano Limon field, Llanos Basin, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Molina, J. [Occidental de Colombia, Inc., Bogota (Colombia)

    1996-08-01

    The Chipaque-Lower Carbonera({circ}) Petroleum System of the northernmost Llanos Basin of Colombia, covers 11,100 km{sup 2} and includes two major oil fields: Caho Limon in Colombia, and Guafita in Venezuela, jointly with three more relatively small fields in Colombia: Redondo, Cano Rondon, and Jiba. Ultimate recoverable reserves are in the order of 1.4 BBO. The sedimentary section penetrated in the Northern Llanos has been informally subdivided into four Cretaceous formations: K3, K2B, K2A, and Lower K1 deposited during the Albian-Senonian, and into four Tertiary formations: Lower Carbonera, Upper Carbonera, Leon, and Guayabo deposited during the Late Eocene to Pliocene time. The main reservoir is the Lower Carbonera Formation, which contains 81% of the total reserves. The Cretaceous K2A and Lower K1 reservoirs contain 6% and 8%, respectively of the reserves. Minor reserves are accumulated in the discontinuous sandstones of the Oligocene Upper Carbonera Formation Geochemical analyses of the Cano Limon/Guafita oils indicate that these are aromatic intermediate to paraffinic-naphthenic, non degradated, genetically related to a common marine-derived type of kerogen. These oils were generated by a mature, marine clastic source rock with a small contribution of continental organic matter. The geochemistry of the hydrocarbon suggest a genetic relationship with the shales of the Chipaque formation, basin-ward equivalent of the K2 Formation, which presents kerogen type II organic matter and has been recognized as a good source rock. The petroleum system is hypothetical because a definite oil-source rock correlation is lacking. The development of the petroleum system is directly related to the history of movement of the Santa Maria, La Yuca, Caho Limon, and Matanegra wrench faults. It has been determined that these faults of pre-Cretaceous rifting origin, created the Santa Maria Graben of which the Espino Graben is the continuation in Venezuela.

  17. Clay Mineral Distribution Patterns of Tertiary Continental Oil-bearing Basins in China

    Institute of Scientific and Technical Information of China (English)

    Zhao Xingyuan

    1996-01-01

    @@ Induction This paper studies the clay mineral distribution patterns of Tertiary continental oil-bearing basins in China. More than 9 000 shale samples from Paleogene (E) to Neogene (N) Series distributed in Bohai Gulf, Subei, Jianghan,Nanxiang, Zhoukou, Sanshui, Beibu Bay, East China Sea,Hetao, Juiquan, Qaidam and Tarim basins, and so on.

  18. Origin of Natural Gas in Kekeya Field, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    Hou Dujie; Xiao Zhongyao; Tang Youjun; Zhu Junzhang; Li Xianqing

    2004-01-01

    This paper is mainly concentrated on the geochemical characteristics and origin of gas of Kekeya field in the Tarim basin, NW China. This study shows that Permian mudstone is the main source rock of oil and gas. Based on the carbon isotopes of C1-C4, the carbon isotope of gas in Kekeya field is a little heavier than that in the typical marine-derived gas. The relationship between carbon isotopes of methane and ethane is coincident with Faber equation of gas derived from organic matter Ⅰ/Ⅱ. The majority of gas maturity is estimated, based on the formula, at 1.8 %-2.2 % besides K2 and K18 wells. In addition, the gas derived from 0.9 %-1.2 % Ro source rocks may also be mixture. 40Ar/36Ar and 3He/4He ratios from the gas samples also support the mixing process. Moreover, the gas in this region is mainly generated from more mature source rocks although the low mature gas exists.

  19. Edge detection in gravity field of the Gheshm sedimentary basin

    Directory of Open Access Journals (Sweden)

    Ali Akbar Hosseini

    2013-06-01

    Full Text Available Edge detection and edge enhancement techniques play an essential role in interpreting potential field data. This paper describes the application of various edge detection techniques to gravity data in order to delineate the edges of subsurface structures. The edge detection methods comprise analytic signal, total horizontal derivative (THDR, theta angle, tilt angle, hyperbolic of tilt angle (HTA, normalised total horizontal gradient (TDX and normalised horizontal derivative (NTHD. The results showed that almost all filters delineated edges of anomalies successfully. However, the capability of these filters in edge detection decreased as the depth of sources increased. Of the edge enhancement filters, normalized standard deviation filter provided much better results in delineating deeper sources. The edge detection techniques were further applied on a real gravity data from the Gheshm sedimentary basin in the Persian Gulf in Iran. All filters specified a northeast-southwest structural trend. The THDR better outlined the structural morphology and trend. Moreover, it indicated the salt plugs much better than other filters. Analytic signal and THDR successfully enhanced the edges of the shorter wavelength residual structures. Normalized standard deviation (NSTD, TDX and hyperbolic of tilt angle (HTA filters highlighted the likely fault pattern and lineaments, with a dominant northeast-southwest structural trend. This case study shows that the edge detection techniques provides valuable information for geologists and petroleum engineers to outline the horizontal location of geological sources including salt plugs and stand out buried faults, contacts and other tectonic and geological features.

  20. Fluid Dynamic Field in Bozhong Depression, Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The data from regional geology, boreholes, geophysics and tests are integrated to analyze the fluid dynamic field in the Bozhong depression, Bohai Bay basin. The current geothermal gradient is determined to be about 2.95 ℃/100 m by integrating 266 drill-stem test (DST) measurements and comparing with the global average value. The paleogeothermal gradients are calculated from the homogenization temperatures of saline inclusions, which vary both laterally and vertically. The data from sonic logs, well tests and seismic velocities are used to investigate the pressure variations in the study area. The mudstone compaction is classified as three major types: normal compaction and normal pressure, under-compaction and overpressure, and past-compaction and under-overpressure. The current pressure profile is characterized by normal pressure, slight pressure and intense overpressure from top to bottom. The faults, unconformity surfaces and interconnecting pores constitute a complex network of vertical and horizontal fluid flows within the depression. The fluid potential energy profiles present a “double-deck” structure. The depocenters are the area of fluids supply, whereas the slopes and uplifts are the main areas of fluids charge.

  1. Field guide to Laramide basin evolution and drilling activity in North Park and Middle Park, Colorado

    Science.gov (United States)

    Dechesne, Marieke; Cole, James Channing; Martin, Christopher B.

    2016-01-01

    Overview of the geologic history of the North Park–Middle Park area and its past and recent drilling activity. Field trip stops highlight basin formation and the consequences of geologic configuration on oil and gas plays and development. The starting point is the west flank of the Denver Basin to compare and contrast the latest Cretaceous through Eocene basin fill on both flanks of the Front Range, before exploring sediments of the same age in the North Park – Middle Park intermontane basin.

  2. Hanford Reach - Snively Basin Rye Field Rehabilitation 2014

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Snively Basin area of the Arid Lands Ecology Reserve within the Hanford Reach National Monument was historically used to farm cereal rye (Secale cereale), among...

  3. Hanford Reach - Snively Basin Rye Field Rehabilitation 2012

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Snively Basin area of the Arid Lands Ecology Reserve (ALE) within the Hanford Reach National Monument was historically used to farm cereal rye, among other...

  4. Transmittal of field data regarding wetlands : Closed Basin Division, San Luis Valley Project, Colorado

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Copies of 1980 field information involving auger hole surveys, soil sample moisture analyses, infiltration tests, and evaporation pan readings from the Closed Basin...

  5. End Late Paleozoic tectonic stress field in the southern edge of Junggar Basin

    Directory of Open Access Journals (Sweden)

    Wei Ju

    2012-09-01

    Full Text Available This paper presents the end Late Paleozoic tectonic stress field in the southern edge of Junggar Basin by interpreting stress-response structures (dykes, folds, faults with slickenside and conjugate joints. The direction of the maximum principal stress axes is interpreted to be NW–SE (about 325°, and the accommodated motion among plates is assigned as the driving force of this tectonic stress field. The average value of the stress index R′ is about 2.09, which indicates a variation from strike-slip to compressive tectonic stress regime in the study area during the end Late Paleozoic period. The reconstruction of the tectonic field in the southern edge of Junggar Basin provides insights into the tectonic deformation processes around the southern Junggar Basin and contributes to the further understanding of basin evolution and tectonic settings during the culmination of the Paleozoic.

  6. Exploration practices and prospect of Upper Paleozoic giant gas fields in the Ordos Basin

    OpenAIRE

    Shengli Xi; Xinshe Liu; Peilong Meng

    2015-01-01

    Natural gas resources is abundant in the Ordos Basin, where six gas fields with more than 100 billion cubic meters of gas reserves have been successively developed and proved, including Jingbian, Yulin, Zizhou, Wushenqi, Sulige and Shenmu. This study aims to summarize the fruitful results and functional practices achieved in the huge gas province exploration, which will be regarded as guidance and reference for the further exploration and development in this basin. Based on the past five deca...

  7. The Linguado, Carapeba, Vermelho, and Marimba giant oil fields, Campos basin, offshore Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Stank, C.V.; Esteves, F.R.; Martins, C.C.; Cruz, W.M.; Da Silva Barroso, A.; Horschutz, P.M.C. (Petrobras, Rio de Janeiro (Brazil))

    1990-09-01

    About 40 hydrocarbon accumulations have been discovered in the Campos basin in the period 1978-1984, including four giant fields in shallow to moderate water depths. The Linguado oil field is located on the extreme south of the producing area of the Campos basin. The pool was discovered in May 1978. The reservoir rocks occur between 1,700 and 3,000 m, and are constituted by fractured Neocomian basalts, Barremian pelecypod coquinas, Albian oolitic calcarenites, and, secondarily, by some Cretaceous turbidite sandstones. The main reservoir is formed by coquinas, which contain 76% of the total recoverable oil volume estimated at 104.6 million bbl. The field is located on a regional high and the accumulation is strongly controlled by stratigraphic and diagenetic factors. High-quality oil is produced through a floating producing system (FPS), and the cumulative oil production amounts to 63.8 million bbl. The Carapeba and Vermelho oil fields are situated in the northern limit of the Campos basin producing area and, together with the smaller Pargo field, make up the so-called Northeast Pole of Campos basin. Carapeba field was discovered in February 1982, and has an estimated recoverable oil volume of 127.8 million bbl. Production comes mainly from two Upper Cretaceous turbidite sandstone reservoirs. The Vermelho field in December 1982, and its main reservoir is formed by a massive Eocene turbidite sandstone. The estimated recoverable oil volume amounts to 119.7 million bbl. Both Carapeba and Vermelho fields are structural traps associated with the development of subtle anticlines caused by salt movements. The fields are gradually being put on stream through five fixed platforms installed in water depths ranging from 70 to 90 m. The Marimba field, discovered in March 1984, drilled in a water depth of 383 m, is considered the first deep-water oil strike in the Campos basin. The field has an estimated recoverable oil volume of 115 million bbl of good-quality oil.

  8. Beyond basin resonance: characterizing wave propagation using a dense array and the ambient seismic field

    Science.gov (United States)

    Boué, Pierre; Denolle, Marine; Hirata, Naoshi; Nakagawa, Shigeki; Beroza, Gregory C.

    2016-08-01

    Seismic wave resonance in sedimentary basins is a well-recognized seismic hazard; however, concentrated areas of earthquake damage have been observed near basin edges, where wave propagation is particularly complex and difficult to understand with sparse observations. The Tokyo metropolitan area is densely populated, subject to strong shaking from a diversity of earthquake sources, and sits atop the deep Kanto sedimentary basin. It is also instrumented with two seismic arrays: the dense MEtropolitan Seismic Observation network (MeSO-net) within the basin, and the High sensitivity seismograph network (Hi-net) surrounding it. In this study, we explore the 3-D seismic wavefield within and throughout the Kanto basin, including near and across basin boundaries, using cross-correlations of all components of ambient seismic field between the stations of these two arrays. Dense observations allow us to observe clearly the propagation of three modes of both Rayleigh and Love waves. They also show how the wavefield behaves in the vicinity of sharp basin edges with reflected/converted waves and excitation of higher modes.

  9. Relationship between UHP eclogite and two different types of granite in the North Qaidam, NW China: Evidence from zircon SHRIMP ages of granites

    Science.gov (United States)

    Wu, C.; Yang, J.; Wooden, J.; Ernst, G. W.; Liou, J. G.; Li, H.; Zhang, J.; Wan, Y.; Shi, R.

    2001-12-01

    The southern margin of the Qilianshan is a long, narrow mountain range extending from the Altyn Mtn southeastward to the Alcitoshan for about 800 km and consists chiefly of Proterozoic and Paleozoic rocks. Our recent studies show that this foldbelt consists of a Caledonian north Qaidam UHP belt near the Qaidam Basin and I-type and S-type granites to the north near the Qilianshan. Two types of granite bodies at the Aolaoshan and Qaidamshan were selected for zircon SHRIMP dating. The results indicate that the Aolaoshan granites range from 496+/-7.6 to 445+/-15.3 Ma whereas the Qaidamshan granites range from 435+/-6 to 456+/-11 Ma. The Aolaoshan granites have geochemical characteristics similar to I-type granite probably formed in an island arc setting whereas the Qaidamshan granites are S type granites coeval with timing of collision. The UHP eclogites at Yuca have 238U-206Pb age of 494.6+/-6.5Ma, representing the peak stage of UHP metamorphism, and the 39 Ar-40Ar plateau and isochron ages of phengite respectively at 466.7+/-1.2 Ma and 465.9+/-5.4Ma represent the cooling ages of retrograde metamorphism during exhumation. In addition, the SHRIMP ages of UHP eclogites from Xitieshan and Dulan are the Caledonian. These spatial and temporal relationships suggest that UHP eclogites and two different types of Caledonian granites occur in north Qaidam with the eclogite belt to the south and the granite bodies to the north. The country rocks of UHP eclogites are Proterozoic age whereas granitic bodies have both Proterozoic and Paleozoic groups. Thus, an early Caledonian northward subduction of an oceanic lithosphere resulted in the formation of high-P eclogite to the south and I type Aolaoshan granite to the north. Subsequent continent-continent collision induced widespread partial melting of continental crust to form S type Qaidamshan granites. Hence both eclogite and two different types of granites in this foldbelt are the products of two different stages of plate

  10. From deep basin gas to diagenetic trap-An example from the Yulin Gas Field in the Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the updip portion of the Yulin Gas Field in the Ordos Basin, there are no any structural, stratigraphic and sedimentary lithologic seals. Using thin-section petrography, ultraviolet fluorescence microscopy, micro-thermometry and Raman microspectrometry, this paper finds out the diagenetic trap and studies the diagenetic history of this field. It was revealed that three phases of diagenesis and hydrocarbon charging happened in late Triassic, late Jurassic and the end of early Cretaceous respectively. In the first two phases, acid geofluid entered the reservoir and caused dissolution and cementation. Although the porosities had been increased, further compaction accompanying re-subsidence resulted in tight sandstone and conglomerates. Till the end of the early Cretaceous, bulk of gas migrated into the tight reservoir. Cementation, however, kept on in the updip portion of this field due to low gas saturation and formed the diagenetic trap. The mechanism for gas accumulation was changed from deep basin gas to diagenetic trap, which offers a sealing condition that can retain gas for much longer time.

  11. Research on construction of water right system for Qaidam circular economy pilot area%柴达木盆地循环经济试验区水权制度建设研究

    Institute of Scientific and Technical Information of China (English)

    王艳

    2014-01-01

    随着柴达木盆地循环经济试验区优势资源开发力度的加大和工业化进程的加快,水资源供需矛盾日益凸显,已严重影响了当地经济社会的持续发展,调整循环经济试验区水资源配置结构,提高水资源科学有效的利用水平已刻不容缓。从建设节水型社会出发,探讨了以水权、水市场理论为基础的柴达木盆地水资源管理体制建设问题。对柴达木盆地水权转让的范围、转让模式、转让价格、转让客体进行了研究。柴达木盆地内的格尔木河和巴音河的初始水权分配工作已初步完成,为建设柴达木盆地节水型社会打下了良好的基础。%With the process of industrialization and the development intensity increment of superior resources in the Qaidam circular economy pilot area of Qinghai Province, the contradiction between water supply and demand is increasingly prominent and water scarcity has become a serious constraint factor to the economic and social sustainable development of Qaidam circular e-conomy pilot area. Adjusting water resources allocation structure and improving scientific and effective water-use level has been of a great urgent problem to be solved. In the view of building water-saving society, the water resources management system based on water rights, water market theories is explored and the transfer range, transfer mode, transfer price, transfer object of water right are researched. The initial water right allocation of Golmud River and Bayin River in Qaidam Basin has been prelimi-narily completed, laying a good foundation for water-saving society building in Qaidam Basin.

  12. Enhancement of the TORIS data base of Appalachian basin oil fields. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-31

    The Tertiary Oil Recovery Information System, or TORIS, was developed by the Department of Energy in the early 1980s with a goal of accounting for 70% of the nation`s original oil in place (OOIP). More than 3,700 oil reservoirs were included in TORIS, but coverage in the Appalachian basin was poor. This TORIS enhancement project has two main objectives: to increase the coverage of oil fields in the Appalachian basin; and to evaluate data for reservoirs currently in TORIS, and to add, change or delete data as necessary. Both of these objectives have been accomplished. The geological surveys in Kentucky, Ohio, Pennsylvania and West Virginia have identified 113 fields in the Appalachian basin to be included in TORIS that collectively contained 80% of the original oil in place in the basin. Furthermore, data in TORIS at the outset of the project was checked and additional data were added to the original 20 TORIS oil fields. This final report is organized into four main sections: reservoir selection; evaluation of data already in TORIS; industry assistance; and data base creation and validation. Throughout the report the terms pool and reservoir may be used in reference to a single zone of oil accumulation and production within a field. Thus, a field is composed of one or more pools at various stratigraphic levels. These pools or reservoirs also are referred to as pay sands that may be individually named sandstones within a formation or group.

  13. Structural mapping based on potential field and remote sensing data, South Rewa Gondwana Basin, India

    Indian Academy of Sciences (India)

    Swarnapriya Chowdari; Bijendra Singh; B Nageswara Rao; Niraj Kumar; A P Singh; D V Chandrasekhar

    2017-08-01

    Intracratonic South Rewa Gondwana Basin occupies the northern part of NW–SE trending Son–Mahanadi rift basin of India. The new gravity data acquired over the northern part of the basin depicts WNW–ESE and ENE–WSW anomaly trends in the southern and northern part of the study area respectively. 3D inversion of residual gravity anomalies has brought out undulations in the basement delineating two major depressions (i) near Tihki in the north and (ii) near Shahdol in the south, which divided into two sub-basins by an ENE–WSW trending basement ridge near Sidi. Maximum depth to the basement is about 5.5 km within the northern depression. The new magnetic data acquired over the basin has brought out ENE–WSW to E–W trending short wavelength magnetic anomalies which are attributed to volcanic dykes and intrusive having remanent magnetization corresponding to upper normal and reverse polarity (29N and 29R) of the Deccan basalt magnetostratigrahy. Analysis of remote sensing and geological data also reveals the predominance of ENE–WSW structural faults. Integration of remote sensing, geological and potential field data suggest reactivation of ENE–WSW trending basement faults during Deccan volcanism through emplacement of mafic dykes and sills. Therefore, it is suggested that South Rewa Gondwana basin has witnessed post rift tectonic event due to Deccan volcanism.

  14. Structural mapping based on potential field and remote sensing data, South Rewa Gondwana Basin, India

    Science.gov (United States)

    Chowdari, Swarnapriya; Singh, Bijendra; Rao, B. Nageswara; Kumar, Niraj; Singh, A. P.; Chandrasekhar, D. V.

    2017-08-01

    Intracratonic South Rewa Gondwana Basin occupies the northern part of NW-SE trending Son-Mahanadi rift basin of India. The new gravity data acquired over the northern part of the basin depicts WNW-ESE and ENE-WSW anomaly trends in the southern and northern part of the study area respectively. 3D inversion of residual gravity anomalies has brought out undulations in the basement delineating two major depressions (i) near Tihki in the north and (ii) near Shahdol in the south, which divided into two sub-basins by an ENE-WSW trending basement ridge near Sidi. Maximum depth to the basement is about 5.5 km within the northern depression. The new magnetic data acquired over the basin has brought out ENE-WSW to E-W trending short wavelength magnetic anomalies which are attributed to volcanic dykes and intrusive having remanent magnetization corresponding to upper normal and reverse polarity (29N and 29R) of the Deccan basalt magnetostratigrahy. Analysis of remote sensing and geological data also reveals the predominance of ENE-WSW structural faults. Integration of remote sensing, geological and potential field data suggest reactivation of ENE-WSW trending basement faults during Deccan volcanism through emplacement of mafic dykes and sills. Therefore, it is suggested that South Rewa Gondwana basin has witnessed post rift tectonic event due to Deccan volcanism.

  15. Structure of an inverted basin from subsurface and field data: the Late Jurassic-Early Cretaceous Maestrat Basin (Iberian Chain)

    Energy Technology Data Exchange (ETDEWEB)

    Nebot, M.; Guimera, J.

    2016-07-01

    The Maestrat Basin experienced two main rifting events: Late Permian-Late Triassic and Late Jurassic-Early Cretaceous, and was inverted during the Cenozoic Alpine orogeny. During the inversion, an E-W-trending, N-verging fold-and-thrust belt developed along its northern margin, detached in the Triassic evaporites, while southwards it also involved the Variscan basement. A structural study of the transition between these two areas is presented, using 2D seismic profiles, exploration wells and field data, to characterize its evolution during the Mesozoic extension and the Cenozoic contraction. The S-dipping Maestrat basement thrust traverses the Maestrat Basin from E to W; it is the result of the Cenozoic inversion of the lower segment–within the acoustic basement–of the Mesozoic extensional fault system that generated the Salzedella sub-basin. The syn-rift Lower Cretaceous rocks filling the Salzedella sub-basin thicken progressively northwards, from 350m to 1100m. During the inversion, a wide uplifted area –40km wide in the N-S direction– developed in the hanging wall of the Maestrat basement thrust. This uplifted area is limited to the North by the E-W-trending Calders monocline, whose limb is about 13km wide in its central part, dips about 5ºN, and generates a vertical tectonic step of 800-1200m. We interpreted the Calders monocline as a fault-bend fold; therefore, a flat-ramp-flat geometry is assumed in depth for the Maestrat basement thrust. The northern synformal hinge of the Calders monocline coincides with the transition from thick-skinned to thin-skinned areas. The vast uplifted area and the low-dip of the monocline suggest a very low-dip for the basement ramp, rooted in the upper crust. The Calders monocline narrows and disappears laterally, in coincidence with the outcrop of the Maestrat basement thrust. The evaporitic Middle Muschelkalk detachment conditioned the structural style. Salt structures are also related to it; they developed during the

  16. THE ADOPTION AND DIFFUSION OF LEVEL FIELDS AND BASINS

    OpenAIRE

    1999-01-01

    Strategic investments in agriculture often are lumpy and irreversible, with significant impacts on operating and fixed costs. Leveling cotton fields to zero slope in central Arizona is a strategic decision made by relatively younger farmers who are farming fine-textured soils in irrigation districts with higher expected water costs. The diffusion of the technology across the region between 1968-89 appears to be both a function of institutional changes (e.g., the Groundwater Management Act of ...

  17. Distribution and Origin of Underground Water Chemical Fields in Songliao Continental Oil—Bearing Sedimentary Basin

    Institute of Scientific and Technical Information of China (English)

    楼章华; 张秉坚; 等

    1999-01-01

    There are many factors affecting ungerground water chemistry of an oil-bearing sedimentary basin.The properties of underground water show variations in the vertical direction, giving rise to a vertical zonation with respect to underground water chemistry,Five zones could be divided downwards,including 1)The freshening zone due to meteoric water leaching (A):2)the evaporation-concentration zone near the surface(B);3) the freshening zone due to stratum compaction-released water(C1)-infiltration-concentration zone during the mudstone compaction and water releasing(C2);4) the freshening zone for clay mineral dehydration(D);and 5)the seepage-concentration zone(E).The hydrodynamic fields in the Songliao Basin are obviously asymmetrical,with the characteristics of gravity-induced centripetal flow recharged by meteoric water along the edge to the inner part of the basin mainly in its northern and eastern regions,centrifugal flow and crossformational flow in the center of the basin,as well as the cross-formation flow-evaporation discharge area in its southern area.Hydrodynamics controls the planar distribution of underground-water chemical fields;1)the freshening area due to penetrating meteoric water generally at the basin edges;2)the freshening area for mudstone compaction-released water at the center of the basin;3) the cross-formational area as the transitional aqrea;and 4)the concentration area by cross-formational flow and evaporation.The mineralization degree and the concentrations of Na+ and Cl- and their salinity coefficeents tend to increase,while the concentrations of(CO32-+HCO3-) and SO42- and the metamorphism and desulfuration coefficients tend to decrease along the centrifugal flow direction caused by mudstone compaction in the depression area.But all of them tend to increase along the gravity-induced centripetal flow direction.

  18. Hydrocarbon potential assessment of Ngimbang formation, Rihen field of Northeast Java Basin

    Science.gov (United States)

    Pandito, R. H.; Haris, A.; Zainal, R. M.; Riyanto, A.

    2017-07-01

    The assessment of Ngimbang formation at Rihen field of Northeast Java Basin has been conducted to identify the hydrocarbon potential by analyzing the response of passive seismic on the proven reservoir zone and proposing a tectonic evolution model. In the case of petroleum exploration in Northeast Java basin, the Ngimbang formation cannot be simply overemphasized. East Java Basin has been well known as one of the mature basins producing hydrocarbons in Indonesia. This basin was stratigraphically composed of several formations from the old to the young i.e., the basement, Ngimbang, Kujung, Tuban, Ngerayong, Wonocolo, Kawengan and Lidah formation. All of these formations have proven to become hydrocarbon producer. The Ngrayong formation, which is geologically dominated by channels, has become a production formation. The Kujung formation that has been known with the reef build up has produced more than 102 million barrel of oil. The Ngimbang formation so far has not been comprehensively assessed in term its role as a source rock and a reservoir. In 2013, one exploratory well has been drilled at Ngimbang formation and shown a gas discovery, which is indicated on Drill Stem Test (DST) reading for more than 22 MMSCFD of gas. This discovery opens new prospect in exploring the Ngimbang formation.

  19. Field based geothermal exploration: Structural controls in the Tarutung Basin/North Central Sumatra (Indonesia)

    Science.gov (United States)

    Nukman, M.; Moeck, I.

    2012-04-01

    The Tarutung Basin is one of several basins along the prominent Sumatra Fault System (SFS) which represents a dextral strike slip fault zone segmented into individual fault strands. The basins are located at right-stepping transfer. The Tarutung Basin hosts geothermal manifestations such as hot springs and travertines indicating a geothermal system with some decent potential in the subsurface. As part of geothermal exploration, field geology is investigated focusing on how the structural setting controls the thermal manifestation distribution. A complex fault pattern is now newly mapped and evidences sinistral faults striking E-W (Silangkitang), normal faults striking SE-NW at the eastern strand of Tarutung Basin (Sitompul) and normal faults striking NW-SE at the western strand of the basin (Sitaka). These structures form an angle greater than 450 with respect to the current maximum principal stress which is oriented in N-S. Secondary sinistral shear fractures identified as antithetic Riedel shears can be correlated with hot spring locations at Silangkitang, forming an angle of 500 with respect to the current maximum stress. A large angle of normal fault and antithetic Riedel shear trend with respect to the current maximum stress direction indicates that the structures have been rotated. Unidentified dextral strike slip faults might exist at the eastern strand of Tarutung Basin to accommodate the clockwise rotation between the eastern boundary of the basin and the NW-SE striking normal fault of Panabungan. Normal faults striking parallel with the SFS East of the basin are interpreted as dilatational jogs caused by the clockwise rotated block movement with respect to the NW-SE fault trend sinistral shear along ENE-WSW faults. Silicified pryroclastics in association with large discharge at hot springs at these NW-SE striking normal faults support this hypothesis. As proposed by Nivinkovich (1976) and Nishimura (1986) Sumatra has rotated 20° clockwise since the last

  20. Evolution of Hydrodynamic Field, Oil-Gas Migration and Accumulation in Songliao Basin, China

    Institute of Scientific and Technical Information of China (English)

    楼章华; 朱蓉; 金爱民; 孙毛明; 蔡希源; 迟元林

    2004-01-01

    The oil-gas migration and accumulation in the Songliao Basin were analyzed in the view of fluid dynamics by the authors. The key point of fluid dynamics is hydrodynamics. Oil-gas migration and accumulation are related closely with formation and evolution of hydrodynamic field. Based on abundant data, initial formation pressure and other parameters, such as water head were studied. They can be used to understand the present distribution of hydrodynamic field and its hydrochemical features. Generally, the hydrodynamic field in the basin is obviously asymmetrical. In its north and east part, there are the areas of centripetal flow caused by topographic relief when meteoric water permeate downwards. Its south part is an evaporation-concentration area. The central depression is an area of centrifugal flow driven by sediment compaction and its cross-formational flow area. Only at the basin margin and in the local uplifted and denudated area are the meteoric water permeating downwards areas. The centrifugal flow driven by sediment compaction is the main dynamic factor that induces oil-gas migration and accumulation and its formation period corresponding to the main stage of oil-gas migration and accumulation. Moreover, the evolution of hydrodynamic field has the cyclic property, which results in phased oil-gas migration by stages, and further dominates the terraced annular oil and gas distribution, concentric with their corresponding sags.

  1. Evolution of the eddy field in the Arctic Ocean's Canada Basin, 2005-2015

    Science.gov (United States)

    Zhao, Mengnan; Timmermans, Mary-Louise; Cole, Sylvia; Krishfield, Richard; Toole, John

    2016-08-01

    The eddy field across the Arctic Ocean's Canada Basin is analyzed using Ice-Tethered Profiler (ITP) and moored measurements of temperature, salinity, and velocity spanning 2005 to 2015. ITPs encountered 243 eddies, 98% of which were anticyclones, with approximately 70% of these having anomalously cold cores. The spatially and temporally varying eddy field is analyzed accounting for sampling biases in the unevenly distributed ITP data and caveats in detection methods. The highest concentration of eddies was found in the western and southern portions of the basin, close to topographic margins and boundaries of the Beaufort Gyre. The number of lower halocline eddies approximately doubled from 2005-2012 to 2013-2014. The increased eddy density suggests more active baroclinic instability of the Beaufort Gyre that releases available potential energy to balance the wind energy input; this may stabilize the Gyre spin-up and associated freshwater increase.

  2. Genesis mechanism of the Sinian-Cambrian reservoirs in the Anyue Gas Field, Sichuan Basin

    OpenAIRE

    Zhou Jingao; Yao Genshun; Yang Guang; Zhang Jianyong; Hao Yi; Wang Fang; Gu Mingfeng; Li Wenzheng

    2015-01-01

    The Lower Cambrian Longwangmiao Fm, the 4th and 2nd members of the Sinian Dengying Fm are the three major gas layers in the Anyue Gas Field of the Sichuan Basin. Their main characteristics and genesis mechanism were investigated, and the following three findings were obtained. First, according to sedimentary microfacies, lithology and porosity, the Longwangmiao Fm is identified as fractured-vuggy dolomite reservoir of grain shoal facies, the 4th member of the Dengying Fm as fractured-vuggy (c...

  3. Origin and Distribution of Groundwater Chemical Fields of the Oilfield in the Songliao Basin, NE China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    There are many factors affecting the chemical characteristics of groundwater in the forming process of groundwater chemical fields, such as freshening due to meteoric water leaching downwards, freshening due to mudstone compaction and water release, concentration due to infiltration and freshening due to dehydration of clay minerals. As a result, the groundwater chemical fields are characterized by lengthwise stages and planar selectivity. The former arouses vertical chemical zonality of groundwater. Five units could be identified downwards in the Songliao basin: (1) freshening zone due to downward-leaching meteoric water, (2) concentration zone due to evaporation near the ground surface, (3)freshening zone due to mudstone compaction and water release, and concentration zone due to compaction and infiltration,(4) freshening zone due to dehydration of clay minerals, and (5) filtration-concentration zone; whereas the latter determines the planar division of groundwater chemical fields: (1) the freshening area due to meteoric water, asymmetrically on the margin of the basin, (2) the freshening area due to mudstone compaction and water release in the central part of the basin, (3)the leaky area, which is a transitional zone, and (4) leakage-evaporation area, which is a concentration zone. In the direction of centrifugal flows caused by mudstone compaction in the depression area, the mineralization degree, concentrations of Na+ and CI-, and salinity coefficient (SC) increase, while concentrations of (CO32-+HCO3-) and SO42-, metamorphism coefficient (MC) and desulfuration coefficient (DSC) decrease. However, all these parameters increase in the direction of gravity-induced centripetal flows.

  4. 柴达木盆地德令哈拗陷中侏罗统烃源岩有机地球化学特征%Organic geochemical characteristics of Middle Jurassic hydrocarbon source rocks in Delingha depression of Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    陈迎宾; 张寿庭

    2011-01-01

    Middle Jurassic is the main layer system of hydrocarbon source rocks which develops widely in the Delingha depression. Field geological survey and organic geochemical analysis indicate that Middle Jurassic source rocks mainly include oil shale, mudstone, carbonaceous mudstone and coal.The oil shale is a good hydrocarbon-generating rock. Whose mass fraction of organic carbon averages 7.95% and the type of organic matter is I and Ⅱ. Mudstone has different organic matter abundances,but over 80% samples whose mass fraction of organic carbon is more than 1% and over 65% samples whose mass fraction of organic carbon is more than 1.5 %. The type of organic matter of mudstone is Ⅱ and Ⅲ 1, and the mudstone is evaluated as poor to moderate source rocks. Carbonaceous mudstone whose mass fraction of organic carbon averages 10. 89 % and the type of organic matter is Ⅲ 1 and Ⅲ 2,so it belongs to poor hydrocarbon source rocks. The coal is the worst, and it belongs to a nonhydrocarbon source rock or poor hydrocarbon source rock. Most of the organic matter in the outcrop source rocks belongs to unbaked to low maturity, and a little of the organic matter belongs to maturity. It can be deduced that most of the organic matter in a peak period of oil generation and expulsion has a high maturity in the depression. The composition and the distribution of hydrocarbon compounds indicate that Middle Jurassic belongs to a fresh water deposit environment, and there develops semi-deep lake facies and deep lake facies which are good depositional settings to deploy source rocks in the Delingha depression.%柴达木盆地德令哈拗陷中侏罗统广泛发育,是该区主要的烃源岩层系.野外地质调查及有机地球化学分析表明,中侏罗统烃源岩主要以油页岩、泥岩、碳质泥岩和煤为主.油页岩有机碳的质量分数平均为7.95%,有机质类型属Ⅰ-Ⅱ型,为好生油岩;泥岩的有机质丰度交化大,但80%以上的样品

  5. Gas Field Development in Sichuan Basin: An Introduction to Typical Reservoirs

    Institute of Scientific and Technical Information of China (English)

    Ran Longhui; Luo Zili

    1996-01-01

    @@ So far 80 gas fields and 50 gas structures have been found in Sichuan Basin. More than 1300 commercial gas wells have been drilled cumulatively, and more than 600 gas wells are gas producers. The gas output is 20 × 106m3 per day, and the cumulative production reaches 140 ×109 m3, with a recovery percentage of about 50%. At present, most of the eight stable production gas fields are located in East Sichuan, with their reserves accounting for13.4% of the total and recovery percent being 35.7%.

  6. Stress field modeling of the Carpathian Basin based on compiled tectonic maps

    Science.gov (United States)

    Albert, Gáspár; Ungvári, Zsuzsanna; Szentpéteri, Krisztián

    2014-05-01

    The estimation of the stress field in the Carpathian Basin is tackled by several authors. Their modeling methods usually based on measurements (borehole-, focal mechanism- and geodesic data) and the result is a possible structural pattern of the region. Our method works indirectly: the analysis is aimed to project a possible 2D stress field over the already mapped/known/compiled lineament pattern. This includes a component-wise interpolation of the tensor-field, which is based on the generated irregular point cloud in the puffer zone of the mapped lineaments. The interpolated values appear on contour and tensor maps, and show the relative stress field of the area. In 2006 Horváth et al. compiled the 'Atlas of the present-day geodynamics of the Pannonian basin'. To test our method we processed the lineaments of the 1:1 500 000 scale 'Map of neotectonic (active) structures' published in this atlas. The geodynamic parameters (i.e. normal, reverse, right- and left lateral strike-slip faults, etc.) of the lines on this map were mostly explained in the legend. We classified the linear elements according to these parameters and created a geo-referenced mapping database. This database contains the polyline sections of the map lineaments as vectors (i.e. line sections), and the directions of the stress field as attributes of these vectors. The directions of the dip-parallel-, strike-parallel- and vertical stress-vectors are calculated from the geodynamical parameters of the line section. Since we created relative stress field properties, the eigenvalues of the vectors were maximized to one. Each point in the point cloud inherits the stress property of the line section, from which it was derived. During the modeling we tried several point-cloud generating- and interpolation methods. The analysis of the interpolated tensor fields revealed that the model was able to reproduce a geodynamic synthesis of the Carpathian Basin, which can be correlated with the synthesis of the

  7. Geothermal field and its relation with coalbed methane distribution of the Qinshui Basin

    Institute of Scientific and Technical Information of China (English)

    SUN Zhanxue; ZHANG Wen; HU Baoqun; LI Wenjuan; PAN Tianyou

    2005-01-01

    The average geothermal gradient in the Qinshui Basin, Shanxi Province, North China, estimated from temperature logging data of 20 boreholes is 28.2±1.03℃/km.The thermal conductivities of 39 rock samples are measured and 20 heat flow values are obtained. The estimated heat flow ranges from 44.75 mW/m2 to 101.81 mW/m2, with a mean of 62.69±15.20 mW/m2. The thermal history reconstruction from the inversion of vitrinite data, using Thermodel for Windows 2004, reveals that the average paleo-heat flow at the time of maximum burial in late Jurassic to early Cretaceous is 158.41 mW/m2 for the north part, 119.57mW/m2 for the central part and 169.43 mW/m2 for the south part of the basin respectively. The reconstruction of the buried history of the strata indicates that the age for the end of sedimentation and the beginning of erosion for the basin is 108-156 Ma, and that the eroded thickness of the strata is 2603 m in the north, 2291 m in the central, and 2528.9 m in the south of the basin respectively. The "higher in the north and the south, lower in the central" distribution pattern of the paleo-heat flow coincides with the distribution of the coal-bed methane spatially and temporally, which shows that the coal-bed methane is controlled by the paleo-geotemperature field in the basin.

  8. Mexico City basin wind circulation during the MCMA-2003 field campaign

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2005-05-01

    Full Text Available MCMA-2003 was a major field campaign investigating the atmospheric chemistry of the Mexico City Metropolitan Area (MCMA in April of 2003. This paper describes the wind circulation patterns during the campaign both within the Mexico City basin and on the regional scale. ''Time roses'' are introduced to concisely analyze the diurnal wind patterns. Three episode types were identified that explain the conditions encountered: ''O3-South'', ''Cold Surge'' and ''O3-North''. These can be diagnosed from a combination of synoptic and basin observations based on whether the day was predominantly cloudy, or whether the O3 peak was in the north or south of the basin. O3-South days have weak synoptic forcing due to an anti-cyclone over the eastern Pacific. Strong solar heating leads to northerly flows in the basin and an evening shift due to a gap flow from the south-east. Peak ozone concentrations are in the convergence zone in the south of the city. Cold Surge days are associated with ''El Norte'' events, with strong surface northerlies bringing cold moist air and rain. Stable conditions lead to high concentrations of primary pollutants and peak ozone in the city center. O3-North days occur when the sub-tropical jet is closer to Mexico City. With strong westerlies aloft, the circulation pattern is the same as O3-South days except for a wind shift in the mid-afternoon leading to ozone peaks in the north of the city. This classification is proposed as a means of understanding pollutant transport in the Mexico City basin and as a basis for future meteorological and chemical analysis. Furthermore, model evaluation and design of policy recommendations will need to take into account the three episode types.

  9. Mexico City basin wind circulation during the MCMA-2003 field campaign

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2005-01-01

    Full Text Available MCMA-2003 was a major field campaign investigating the atmospheric chemistry of the Mexico City Metropolitan Area (MCMA in April of 2003. This paper describes the wind circulation patterns during the campaign both within the Mexico City basin and on the regional scale. ''Time roses'' are introduced to concisely analyze the diurnal wind patterns. Three episode types were identified that explain the conditions encountered: ''O3-South'', ''Cold Surge'' and ''O3-North''. These can be diagnosed from a combination of synoptic and basin observations based on whether the day was predominantly cloudy, or whether the O3 peak was in the north or south of the basin. O3-South days have weak synoptic forcing due to an anti-cyclone over the eastern Pacific. Strong solar heating leads to northerly flows in the basin and an evening shift due to a gap flow from the south-east. Peak ozone concentrations are in the convergence zone in the south of the city. Cold Surge days are associated with ''El Norte'' events, with strong surface northerlies bringing cold moist air and rain. Stable conditions lead to high concentrations of primary pollutants and peak ozone in the city center. O3-North days occur when the sub-tropical jet is closer to Mexico City. With strong westerlies aloft, the circulation pattern is the same as O3-South days except for a wind shift in the mid-afternoon leading to ozone peaks in the north of the city. This classification is proposed as a means of understanding pollutant transport in the Mexico City basin and as a basis for future meteorological and chemical analysis. Furthermore, model evaluation and design of policy recommendations will need to take into account the three episode types.

  10. Derivation of Geodesic Flow Fields and Spectrum in Digital Topographic Basins

    Directory of Open Access Journals (Sweden)

    Sin Liang Lim

    2008-01-01

    Full Text Available We present a framework to characterize terrestrial functions—surficial and bottom topographic regions that are represented, respectively, as raster digital elevation models (DEMs and digital bathymetric models (DBMs—through analysis of flow fields that are simulated via geodesic morphology. Characterization of such functions is done via a new descriptor. Computation of this new descriptor involves the following steps: (i basin in digital form representing topographic fluctuations as an input, (ii threshold decomposition of basin—that consists of channelized and nonchannelized regions—into sets, (iii proper indexing of these sets to decide the marker set(s and its (their corresponding mask set(s, (iv performing geodesic propagation that provides basic flow field structures, and (v finally providing a new basin descriptor—geodesic spectrum. We demonstrated this five-step framework on five different synthetic and/or realistic DEMs and/or DBMs. This study provides potentially invaluable insights to further study the travel-time flood propagation within basins of both fluvial and tidal systems.

  11. Flood control and loss estimation for paddy field at midstream of Chao Phraya River Basin, Thailand

    Science.gov (United States)

    Cham, T. C.; Mitani, Y.

    2015-09-01

    2011 Thailand flood has brought serious impact to downstream of Chao Phraya River Basin. The flood peak period started from August, 2011 to the end of October, 2011. This research focuses on midstream of Chao Phraya River Basin, which is Nakhon Sawan area includes confluence of Nan River and Yom River, also confluence of Ping River and Nan River. The main purpose of this research is to understand the flood generation, estimate the flood volume and loss of paddy field, also recommends applicable flood counter measurement to ease the flood condition at downstream of Chao Phraya River Basin. In order to understand the flood condition, post-analysis is conducted at Nakhon Sawan. The post-analysis consists of field survey to measure the flood marks remained and interview with residents to understand living condition during flood. The 2011 Thailand flood generation at midstream is simulated using coupling of 1D and 2D hydrodynamic model to understand the flood generation during flood peak period. It is calibrated and validated using flood marks measured and streamflow data received from Royal Irrigation Department (RID). Validation of results shows good agreement between simulated result and actual condition. Subsequently, 3 scenarios of flood control are simulated and Geographic Information System (GIS) is used to assess the spatial distribution of flood extent and reduction of loss estimation at paddy field. In addition, loss estimation for paddy field at midstream is evaluated using GIS with the calculated inundation depth. Results show the proposed flood control at midstream able to minimize 5% of the loss of paddy field in 26 provinces.

  12. Geothermal Resource Analysis and Structure of Basin and Range Systems, Especially Dixie Valley Geothermal Field, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    David Blackwell; Kenneth Wisian; Maria Richards; Mark Leidig; Richard Smith; Jason McKenna

    2003-08-14

    Publish new thermal and drill data from the Dizie Valley Geothermal Field that affect evaluation of Basin and Range Geothermal Resources in a very major and positive way. Completed new geophysical surveys of Dizie Valley including gravity and aeromagnetics and integrated the geophysical, seismic, geological and drilling data at Dizie Valley into local and regional geologic models. Developed natural state mass and energy transport fluid flow models of generic Basin and Range systems based on Dizie Valley data that help to understand the nature of large scale constraints on the location and characteristics of the geothermal systems. Documented a relation between natural heat loss for geothermal and electrical power production potential and determined heat flow for 27 different geothermal systems. Prepared data set for generation of a new geothermal map of North American including industry data totaling over 25,000 points in the US alone.

  13. Integrated Analysis on Gravity and Magnetic Fields of the Hailar Basin, NE China: Implications for Basement Structure and Deep Tectonics

    Science.gov (United States)

    Sun, B.; Wang, L.; Dong, P.; Scientific Team Of Applied Geophysics

    2010-12-01

    The Hailar Basin is one of the most representative basins among the Northeast China Basin Group, which is situated in the east of East Asia Orogene between the Siberia Plate and the North China Plate. Based on the detailed analysis of the Bouguer gravity anomaly, aeromagnetic anomaly as well as petrophysical data, we studied the features of gravity-magnetic fields in the basin and its neighboring areas. A combined approach of Wavelet Multi-scale Decomposition and Power Spectrum Analysis was adopted to quantitatively grade the gravity and magnetic anomalies into four levels. Accordingly, the apparent depths of the source fields can be assessed. The results reveal the crustal density and magnetic structures of the Hailar Basin. Low-order wavelet details of gravity-magnetic anomalies were carried out on studying basin basement structure. Seven major basement faults of the basin were identified, and the basement lithology was discussed and predicted. Three major uplifts and 14 depressions were delineated according to basement depth inversion by the Park method. High-order wavelet approximations of gravity-magnetic anomalies were carried out on studying deep tectonics of the basin. The average Moho depth of the study area is about 40 km, with a mantle uplift located in the northeast of the basin. The average depth of the Curie interface is about 19 km, while the uplift of the Curie interface is in the basin center and its east and west sides are depressions. Finally, inversion of Bouguer gravity anomalies was conducted on an across-basin GGT profile using the Wavelet Multi-scale Decomposition. The inversion results are consistent with those of GGT seismic inversion, suggesting that the Wavelet Multi-scale Decomposition can be applied to distinguish major crustal density interfaces.

  14. Seismic Traveltime Tomography Applied to Data from Miranga Field, Reconcavo Basin, Brazil

    Science.gov (United States)

    Bassrei, A.; Rodrigues, V.

    2015-12-01

    The growing global demand for hydrocarbons has tested the limits of oil exploration and exploitation technologies. Within the seismic methods, tomography is an alternative for the high resolution characterization of reservoirs, enabling a more efficient recovery of new as well as mature fields. In this work, seismic traveltime tomography in the transmission mode was applied to real data from the Miranga Field, Reconcavo Basin, State of Bahia, Brazil. This basin represents a landmark of oil exploration in Brazil and has been intensively studied since the 1950s. Today, the Reconcavo Basin is still the principal oil producer in the State of Bahia, but there is a demand for new technologies, especially for mature fields, to improve hydrocarbon recovery. The objective is to estimate the two-dimensional velocity distribution in the region between the two wells. We have used linearized inversion through the Levenberg-Marquardt scheme. The input data in the system are the traveltimes between the sources and the receivers and the distances propagated by each ray connecting such sources and receivers. Both inputs are provided through acoustic forward modeling. The conjugate gradient algorithm with regularization through derivative matrices was used as an inverse procedure. The tomographic inversion is an ill-posed problem because the existence, uniqueness and stability conditions are not completely satisfied. The linear system is regularized by derivative matrices derived to minimize the instability. This regularization procedure has a crucially important parameter called regularization parameter lambda. For the selection of lambda we used L-curve and Theta-curve. The estimated tomograms were consistent with previous geological knowledge of the area and the P-wave velocity range was consistent. The results showed that traveltime tomography is feasible for the characterization of reservoirs with a high rate of vertical change, similar to the Miranga Field.

  15. Anisotropic mechanical behaviour of sedimentary basins inferred by advanced radar interferometry above gas storage fields

    Science.gov (United States)

    Teatini, P.; Gambolati, G.; Ferretti, A.

    2010-12-01

    Natural gas is commonly stored underground in depleted oil and gas fields to provide safe storage capacity and deliverability to market areas where production is limited, or to take advantage of seasonal price swings. In response to summer gas injection and winter gas withdrawal the reservoir expands and contracts with the overlying land that moves accordingly. Depending on the field burial depth, a few kilometres of the upper lithosphere are subject to local three-dimensional deformations with the related cyclic motion of the ground surface being both vertical and horizontal. Advanced Persistent Scatterer Interferometry (PSI) data, obtained by combining ascending and descending RADARSAT-1 images acquired from 2003 to 2008 above gas storage fields located in the sedimentary basin of the Po river plain, Italy, provide reliable measurement of these seasonal vertical ups and downs as well as horizontal displacements to and from the injection/withdrawal wells. Combination of the land surface movements together with an accurate reconstruction of the subsurface geology made available by three-dimensional seismic surveys and long-time records of fluid pore pressure within the 1000-1500 m deep reservoirs has allowed for the development of an accurate 3D poro-mechanical finite-element model of the gas injection/removal occurrence. Model calibration based on the observed cyclic motions, which are on the range of 10-15 mm and 5-10 mm in the vertical and horizontal west-east directions, respectively, helps characterize the nonlinear hysteretic geomechanical properties of the basin. First, using a basin-scale relationship between the oedometric rock compressibility cM in virgin loading conditions versus the effective intergranular stress derived from previous experimental studies, the modeling results show that the ratio s between loading and unloading-reloading cM is about 4, consistent with in-situ expansions measured by the radioactive marker technique in similar reservoirs

  16. Exploration practices and prospect of Upper Paleozoic giant gas fields in the Ordos Basin

    Directory of Open Access Journals (Sweden)

    Shengli Xi

    2015-11-01

    Full Text Available Natural gas resources is abundant in the Ordos Basin, where six gas fields with more than 100 billion cubic meters of gas reserves have been successively developed and proved, including Jingbian, Yulin, Zizhou, Wushenqi, Sulige and Shenmu. This study aims to summarize the fruitful results and functional practices achieved in the huge gas province exploration, which will be regarded as guidance and reference for the further exploration and development in this basin. Based on the past five decades' successful exploration practices made by PetroChina Changqing Oilfield Company, we first comb the presentation of geological theories at different historical stages as well as the breakthrough in the course. Then, we analyze a complete set of adaptive techniques obtained from the long-time technological research and conclude historical experiences and effective measures in terms of broadening exploration ideas, such as the fluvial delta reservoir-forming theory, giant tight gas reservoir-forming theory, the idea of sediment source system in the southern basin, etc., and innovating technical and management mechanism, such as all-digit seismic prediction, fine logging evaluation for gas formations, stimulation of tight sand reservoirs, flat project and benchmarking management, and so on.

  17. Chaotic dynamics and basin erosion in nanomagnets subject to time-harmonic magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    D' Aquino, M., E-mail: daquino@uniparthenope.it [Engineering Department, University of Naples “Parthenope”, 80143 Naples (Italy); Quercia, A.; Serpico, C. [DIETI, University of Naples Federico II, 80125 Naples (Italy); Bertotti, G. [Istituto Nazionale di Ricerca Metrologica, 10135 Torino (Italy); Mayergoyz, I.D. [ECE Department and UMIACS, University of Maryland, College Park, MD 20742 (United States); Perna, S. [DIETI, University of Naples Federico II, 80125 Naples (Italy); Ansalone, P. [Istituto Nazionale di Ricerca Metrologica, 10135 Torino (Italy)

    2016-04-01

    Magnetization dynamics in uniformly magnetized particles subject to time-harmonic (AC) external fields is considered. The study is focused on the behavior of the AC-driven dynamics close to saddle equilibria. It happens that such dynamics has chaotic nature at moderately low power level, due to the heteroclinic tangle phenomenon which is produced by the combined effect of AC-excitations and saddle type dynamics. By using analytical theory for the threshold AC excitation amplitudes necessary to create the heteroclinic tangle together with numerical simulations, we quantify and show how the tangle produces the erosion of the safe basin around the stable equilibria.

  18. Exposures and cancer incidence near oil fields in the Amazon basin of Ecuador

    OpenAIRE

    San, S.; Armstrong, B; Cordoba, J.; Stephens, C.

    2001-01-01

    OBJECTIVES—To examine environmental exposure and incidence and mortality of cancer in the village of San Carlos surrounded by oil fields in the Amazon basin of Ecuador.
METHODS—Water samples of the local streams were analyzed for total petroleum hydrocarbons (TPHs). A preliminary list of potential cancer cases from 1989 to 1998 was prepared. Cases were compared with expected numbers of cancer morbidity and mortality registrations from a Quito reference population.
RESULTS—Water analysis showe...

  19. Tectono-sedimentary evolution of an extensional basin revealed by a combined photo-geological and field-mapping approach. The Montefalco Basin (Northern Apennines, Italy)

    Science.gov (United States)

    Bucci, Francesco; Mirabella, Francesco; Santangelo, Michele; Cardinali, Mauro; Guzzetti, Fausto

    2016-04-01

    the evolution of the basin. Furthermore, results demonstrate that integration of accurate photo-geological maps produced through API and geological field mapping, can contribute to: (i) characterize the tectono-stratigraphic architecture and the geomorphological evolution of continental basins, (ii) help mineral reserves investigation, (iii) provide new input for active tectonic studies, (iv) produce new geological maps in other continental and marine basins, where field data are hard to collect.

  20. Accumulation Mechanisms and Evolution History of the Giant Puguang Gas Field, Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    HAO Fang; GUO Tonglou; DU Chunguo; ZOU Huayao; CAI Xunyu; ZHU Yangming; LI Pingping; WANG Chunwu; ZHANG Yuanchun

    2009-01-01

    Solid bitumens were found throughout the carbonate reservoirs in the Puguang gas field,the largest gas field SO far found in marine carbonates in China,confirming that the Puguang gas field evolved from a paleo-oil reservoir.The fluid conduit system at the time of intensive oil accumulation in the field Was reconstructed,and petroleum migration pathways were modeled using a 3-D model and traced by geochemical parameters.The forward modeling and inversion tracing coincided with each other and both indicated that oils accumulated in the Puguang-Dongyuezhai structure originated from a generative kitchen to the northwest of the Puguang gas field.The deposition of organic-rich Upper Permian source rocks dominated by sapropelic organic matter in the Northeast Sichuan Basin, the development of fluid conduit system that was vertically near-source rock and laterally near-generative kitchen,and the focusing of oils originated from a large area of the generative kitchen,were the three requirements for the formation of the giant paleo-oil reservoir from which the giant Puguang gas field evolved.The Puguang gas field had experienced a three-stage evolution.The post-accumulation processes,especially the organic-inorganic interaction in the hydrocarbon-water-rock system,had not only profoundly altered the composition and characteristics of the petroleum fluids,but also obviously changed the physicochemical conditions in the reservoir and resulted in complicated precipitation and solution of carbonate minerals.

  1. Summary of 2012 reconnaissance field studies related to the petroleum geology of the Nenana Basin, interior Alaska

    Science.gov (United States)

    Wartes, Marwan A.; Gillis, Robert J.; Herriott, Trystan M.; Stanley, Richard G.; Helmold, Kenneth P.; Peterson, C. Shaun; Benowitz, Jeffrey A.

    2013-01-01

    The Alaska Division of Geological & Geophysical Surveys (DGGS) recently initiated a multi-year review of the hydrocarbon potential of frontier sedimentary basins in Alaska (Swenson and others, 2012). In collaboration with the Alaska Division of Oil & Gas and the U.S. Geological Survey we conducted reconnaissance field studies in two basins with recognized natural gas potential—the Susitna basin and the Nenana basin (LePain and others, 2012). This paper summarizes our initial work on the Nenana basin; a brief summary of our work in the Susitna basin can be found in Gillis and others (in press). During early May 2012, we conducted ten days of helicopter-supported fieldwork and reconnaissance sampling along the northern Alaska Range foothills and Yukon–Tanana upland near Fairbanks (fig. 1). The goal of this work was to improve our understanding of the geologic development of the Nenana basin and to collect a suite of samples to better evaluate hydrocarbon potential. Most laboratory analyses have not yet been completed, so this preliminary report serves as a summary of field data and sets the framework for future, more comprehensive analysis to be presented in later publications.

  2. Erythrocyte invasions and receptor heterogeneity in field isolates of Nanay river basin Iquitos

    Institute of Scientific and Technical Information of China (English)

    Kuppusamy Chenniappan; Sarah H Johns

    2012-01-01

    Objective:To determine whether the requirements for sialic acid varies and whether several types of silaic acid independent receptors utilized for invasion mechanisms of fresh filed isolates collected aroundNanay river basin,Iquitos.Methods:The field isolates were cultured as described previously byJensen andTrager andMR4 protocol with little modifications.The erythrocytes preparation and subsequent enzyme treatment was done as described previously bySharma. with little modification.Invasion assay was performed as described previously by Sharmaet al with little modification.Results:TheNanay river basin isolates showed five types of invasion mechanisms or types of receptors-ligand interactions.Here we observed that an equal numbers of neuraminidase sensitive and resistant invasion receptor-ligand interaction profiles as the most common receptor-ligand invasion profiles.Neuraminidase resistance trypsin sensitive chymotrypsin sensitive(NMRTSCTS) invasion of receptor-ligand interaction profile was found in seven isolates,Five field isolates and one reference strain showed neuraminidase sensitive, trypsin sensitive and chymotrypsin resistant(NMSTSCTR) invasion of receptor-ligand interactions, six isolates including one reference strains dd2 showed neuraminidase sensitive, trypsin and chymotrypsin resistance(NMSTRCTR) indicating its dependence on sialic acids and independence of trypsin and chymotrypsin sensitive proteins.Four isolates showed neuraminidase sensitive, trypsin sensitive and chymotrypsin sensitive(NMSTSCTS) invasion of receptor-ligand interactions, seven isolates were neuraminidase resistant, trypsin sensitive and chymotrypsin resistance (NMRTSCTR) invasion of receptor-ligand interactions, indicating its dependence on trypsin sensitive proteins.Conclusions:TheNanay river basin isolates showed five types of invasion mechanisms or types of receptors-ligand interactions.A full understanding of theses invasion mechanisms may allow the development of novel

  3. Ground motion prediction for the Vienna Basin area using the ambient seismic field

    Science.gov (United States)

    Schippkus, Sven; Zigone, Dimitri; Bokelmann, Götz; AlpArray Working Group

    2016-04-01

    The Vienna Basin is one of the most seismically active regions in Austria. Because of the population density and sensitive infrastructure, seismic hazard assessment in this area is of critical importance. An important part of seismic hazard analysis is ground motion prediction, which can in principle be done using either empirical studies to derive ground motion prediction equations (GMPEs) or using a physics-based approach to simulate ground motion by modelling surface wave propagation. Recently a new method has been presented that is based on the emergence of the inter-station Green's function from ambient noise cross-correlations (Denolle et al. 2013), which provides the impulse response of the Earth from a point source at the surface (from the site of one of the two receivers to the other). These impulse responses are dominated by surface waves, which would, in the case of a real earthquake, cause the major damages. The Green's function can in principle be modified to simulate a double couple dislocation at depth, i.e., a virtual earthquake. Using an adapted pre-processing method, the relative amplitudes of the ambient noise records of different inter-station paths are preserved in the correlation functions, and effects like attenuation and amplification of surface waves in sedimentary basins can be studied. This provides more precise information that will help improve seismic hazard evaluations. Here we present a preliminary study of such ground motion prediction for the Vienna Basin using about two dozen broadband stations from available networks in the area, e.g., stations from the University of Vienna (AlpArray) and Vienna Technical University. References Denolle, M. A., E. M. Dunham, G. A. Prieto, and G. C. Beroza (2013), Ground motion prediction of realistic earthquake sources using the ambient seismic field, J. Geophys. Res. Solid Earth, 118, 2102-2118, doi:10.1029/2012JB009603.

  4. Geochemical evidence of water-soluble gas accumulation in the Weiyuan gas field, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Shengfei Qin

    2016-01-01

    Full Text Available At present, there are several different opinions on the formation process of the Weiyuan gas field in the Sichuan Basin and the source of its natural gas. In view of the fact that the methane carbon isotope of the natural gas in the Weiyuan gas field is abnormally heavy, the geologic characteristics of gas reservoirs and the geochemical characteristics of natural gas were first analyzed. In the Weiyuan gas field, the principal gas reservoirs belong to Sinian Dengying Fm. The natural gas is mainly composed of methane, with slight ethane and trace propane. The gas reservoirs are higher in water saturation, with well preserved primary water. Then, it was discriminated from the relationship of H2S content vs. methane carbon isotope that the heavier methane carbon isotope of natural gas in this area is not caused by thermochemical sulfate reduction (TSR. Based on the comparison of methane carbon isotope in this area with that in adjacent areas, and combined with the tectonic evolution background, it is regarded that the natural gas in the Weiyuan gas field is mainly derived from water-soluble gas rather than be migrated laterally from adjacent areas. Some conclusions are made. First, since methane released from water is carbon isotopically heavier, the water-soluble gas accumulation after degasification results in the heavy methane carbon isotope of the gas produced from Weiyuan gas field. Second, along with Himalayan movement, great uplift occurred in the Weiyuan area and structural traps were formed. Under high temperature and high pressure, the gas dissolved in water experienced decompression precipitation, and the released natural gas accumulated in traps, consequently leading to the formation of Weiyuan gas field. Third, based on calculation, the amount of natural gas released from water which is entrapped in the Weiyuan gas field after the tectonic uplift is basically equal to the proved reserves of this field, confirming the opinion of water

  5. Geochemical Characteristics and Origin of Tar Mats from the Yaha Field in Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    张敏; 张俊; 等

    1999-01-01

    Tar mats were firstly discovered and determined accurately in terrestrial oil and gas reservoirs associated with Lower Tertiary sandstone reservoirs in the Yaha field of the Tarim Basin,China,by thin-layer chromatography-flame ionization detector(TLC-FID)and Rock-Eval analysis.The relative content of asphaltene in gross composition of tar mat extracts accounts for more than 30%,that in the corresponding oil leg less than 20%.In the geochemical description profile of oil gas reservoirs,drastic changes in asphaltene contents between tar mats and oil legs could be discovered.This in an important marker to determine tar mats.Distribution characteristics of saturated and aromaic hydrocarbons from reservoir core extracts and crude oils in the Yaha oil and gas reservoirs in the Tarim Basin are described systematically in this paper,and the results show there are similarities among n-alkane distribution characteristics,biomarker distribution characteristics and their combined characteristics of saturated hydrocarbons,and the geochemical characteristics of aromatic hydrocarbons for tar mats.oil leg,asphaltic sand and crude oil.These characteristics suggest the hydrocarbons in these samples were originated from the common source rocks.However,the geochemical characteristics of tar mats reveales that the mechanism of formation of tar mats is the precipitation of asphaltene from crude oils in petroleum reservoirs caused by increased dissolved gas in oil legs(gas injection).

  6. Evolution of the Moxizhuang Oil Field, Central Junggar Basin, Northwest China

    Institute of Scientific and Technical Information of China (English)

    Zou Huayao; Zhang Yuanchun; Liu Jianzhang; Shi Jiannan

    2008-01-01

    Current oil saturation in the Moxizhuang (莫西庄) Oil Field in central Janggar (准噶尔) basin was evaluated by logging interpretation and measured on core samples, and the paleo-oil saturation in both the pay zones and water zones was investigated by graln-containing-oil inclusion (GOI) analysis.The pay zones in this field have low oil saturation and display low resistivity and small contrast between pay zones and water zones, and are classified as low-porosity, low oil saturation, and low resistivity reservoirs. Both the current low oil-saturation pay zones and the water zones above 4 365 m have high GOI values (up to 38%), suggesting high paleo-oil saturation. The significant difference between current oil saturation from both logging interpretation and core sample measurement and paleo-oil saturation indicated by GOI analysis suggests that this low oil-saturation field evolved from a high oil-saturation pool. Lateral re-migration and spill of formally trapped oil owing to changes in structural configuration since Neogene was the most plausible mechanism for oil loss in the Moxizhuang Oil Field.The combined effects of differential accumulation in the charge phase and the differential re-migration and spill of accumulated oil in Neogene are responsible for the complicated correlation between residual oil saturation and porosity/permeability of the reservoir sandstones and the distribution of low oil-saturation pay zones and paleo-oil zones (current water zones).

  7. Basin-scale wind transport during the MILAGRO field campaign and comparison to climatology using cluster analysis

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2007-09-01

    Full Text Available The MILAGRO field campaign was a multi-agency international collaborative project to evaluate the regional impacts of the Mexico City air pollution plume as a means of understanding urban impacts on the global climate. Mexico City lies on an elevated plateau with mountains on three sides and has complex mountain and surface-driven wind flows. This paper asks what the wind transport was in the basin during the field campaign and how representative it was of the climatology. Surface meteorology and air quality data, radiosoundings and radar wind profiler data were collected at sites in the basin and its vicinity. Cluster analysis is used to identify the dominant wind patterns both during the campaign and within the past 10 years of operational data from the warm dry season. Our analysis shows that March 2006 was representative of typical flow patterns experienced in the basin. Six episode types were identified for the basin scale circulation providing a way of interpreting atmospheric chemistry and particulate data collected during the campaign. Decoupling between surface winds and those aloft had a strong influence in leading to convection and poor air quality episodes. Hourly characterisation of wind circulation during the MILAGRO, MCMA-2003 and IMADA field campaigns will enable the comparisons of similar air pollution episodes and the evaluation of the impact of wind transport on measurements of the atmospheric chemistry taking place in the basin.

  8. Basin-scale wind transport during the MILAGRO field campaign and comparison to climatology using cluster analysis

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2008-03-01

    Full Text Available The MILAGRO field campaign was a multi-agency international collaborative project to evaluate the regional impacts of the Mexico City air pollution plume as a means of understanding urban impacts on the global climate. Mexico City lies on an elevated plateau with mountains on three sides and has complex mountain and surface-driven wind flows. This paper asks what the wind transport was in the basin during the field campaign and how representative it was of the climatology. Surface meteorology and air quality data, radiosondes and radar wind profiler data were collected at sites in the basin and its vicinity. Cluster analysis was used to identify the dominant wind patterns both during the campaign and within the past 10 years of operational data from the warm dry season. Our analysis shows that March 2006 was representative of typical flow patterns experienced in the basin. Six episode types were identified for the basin-scale circulation providing a way of interpreting atmospheric chemistry and particulate data collected during the campaign. Decoupling between surface winds and those aloft had a strong influence in leading to convection and poor air quality episodes. Hourly characterisation of wind circulation during the MILAGRO, MCMA-2003 and IMADA field campaigns enables the comparisons of similar air pollution episodes and the evaluation of the impact of wind transport on measurements of the atmospheric chemistry taking place in the basin.

  9. Energy Field Adjustment and Hydrocarbon Phase Evolution in Sinian-Lower Paleozoic,Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    Liu Shugen; Wang Hua; Sun Wei; Wang Guozhi; Xu Guosheng; Yuan Haifeng

    2008-01-01

    The Sinian-Lower Paleozoic (also called the lower association) in Sichuan (四川) basin has undergone geologic evolution for several hundred million years.The subsidence history of the Sinian-Lower Paleozoic can be divided into four stages:the stable subsidence during Cambrian and Silurian; the uplift and denudation during Devonian and Carboniferous; the subsidence (main process)during Permian to Late Cretaceous; and the rapid uplift and denudation since Late Cretaceous.The later two stages could be regarded as critical factors for the development of oil and gas in the lower association.The evolution of energy field such as temperature,pressure,and hydrocarbon phase in the lower association during the deep burial and uplift in the third stage might be induced as follows:(1)super-high pressure was developed during oil-cracking,previous super-high pressure was sustained,or changed as normal pressure during late uplift; (2) temperature increased with deep burial during persistent subsidence and decreased during uplift in late stage; (3) as a response to the change of the energy field,hydrocarbon phase experienced a series of changes such as organic material (solid),oil (liquid),oil-cracking gas (gaseous) + bitumen (solid) + abnormal high pressure,gas cap gas with super-high pressure (gaseous) + bitumen (solid) + water soluble gas (liquid),and gas in pool (gaseous) + water soluble gas (liquid) + bitumen (solid).The restoration of hydrocarbon phase evolution is of important value for the exploration of natural gas in the Sinian-Lower Paleozoic in Sichuan basin.

  10. Comparison of field and laboratory weathering rates in carbonate rocks from an Eastern Mediterranean drainage basin

    Science.gov (United States)

    Levenson, Yael; Ryb, Uri; Emmanuel, Simon

    2017-05-01

    The rates of carbonate rock weathering affect the global carbon cycle over timescales of hundreds to thousands of years. While field measurements show that the rate of carbonate denudation increases with rainfall, significant variability exists. To determine whether the mineralogical composition of the rocks causes this variability, we compare published long-term field denudation rates determined from cosmogenic isotopes (36Cl) with the weathering rates measured in laboratory experiments conducted on the same rock samples. The samples were collected from natural-rock outcrops across the Soreq drainage basin (Israel) that experience similar mean annual precipitation, but exhibit long-term denudation rates that vary from 6 mm ky-1 to 20 mm ky-1. In laboratory experiments, we found that the laboratory rates also varied, decreasing as the ratio of dolomite to calcite increased. However, no correlation was evident between the long-term denudation rates and mineral composition, suggesting that the variability in field rates was not controlled by the kinetics of dissolution. Other factors, such as rain intensity, biological activity, and mechanical erosion are likely to control the variability in the rates by inhibiting or accelerating the weathering of carbonate surfaces in natural settings.

  11. CBM in 3-D: coalbed methane multicomponent 3-D reservoir characterisation study, Cedar Hill Field, San Juan Basin, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Davis, T.; Shuck, E.; Benson, R. [Colorado School of Mines, Golden, CO (United States). Dept. of Geophysics

    1995-10-01

    The article explains how 3-D multicomponent seismic surveys could substantially improve the production and development of fractured coalbed methane reservoirs. The technique has been used by Northern Geophysical for the detection of geological faults and zones of enhanced fracture permeability proximal to the fault in the western side of the Cedar Hill field in San Juan Basin, NM, USA. 3 figs.

  12. Assessment of remaining recoverable oil in selected major oil fields of the Permian Basin, Texas and New Mexico

    Science.gov (United States)

    Tennyson, Marilyn E.; Cook, Troy A.; Charpentier, Ronald R.; Gautier, Donald L.; Klett, Timothy R.; Verma, Mahendra K.; Ryder, Robert T.; Attanasi, E.D.; Freeman, P.A.; Le, Phoung A.

    2012-01-01

    The U.S. Geological Survey (USGS) recently completed an estimate of technically recoverable, conventional oil in selected oil fields in the Permian Basin in west Texas and southeastern New Mexico. The mean total volume of potential additional oil resources that might be added using improved oil-recovery technologies was estimated to be about 2.7 billion barrels of oil.

  13. Methane microseepage from different sectors of the Yakela condensed gas field in Tarim Basin, Xinjiang, China

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junhong, E-mail: Tang_jhjh@tom.com [Dept. of Environmental Engineering and Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Yin Haoyong [Dept. of Environmental Engineering and Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Wang Guojian [Wuxi Research Institute of Petroleum Geology, Research Institute of Petroleum Exploration and Production, SINOPEC, Wuxi, Jiangsu 214151 (China); Chen Yueyuan [Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products, Ministry of Land and Resources, Lanzhou 730070 (China)

    2010-08-15

    Research highlights: {yields} Dry soil over a petroleum field may give positive fluxes of CH{sub 4} due to microseepage from the underground hydrocarbon accumulations. {yields} Microseepage flux is influenced by subsurface geo-structural features and gas-oil setting. {yields} The {sup 13}C/{sup 12}C ratios of CH{sub 4} in the flux chambers demonstrates that seeping methane is thermogenic. - Abstract: Methane microseepage is the result of natural gas migration from subsurface hydrocarbon accumulations to the Earth's surface, and it is quite common in commercial petroleum fields. While the role of microseepage as a pathfinder in petroleum exploration has been known for about 80 a, its significance as an atmospheric CH{sub 4} source has only recently been studied, and flux data are currently available only in the USA and Europe. With the aim of increasing the global data-set and better understanding flux magnitudes and variabilities, microseepage is now being extensively studied in China. A static flux chamber method was recently applied to study microseepage emissions into the atmosphere in four different sectors of the Yakela condensed gas field in Tarim Basin, Xinjiang, China, and specifically in: (a) a faulted sector, across the Luntai fault systems; (b) an oil-water interface sector, at the northern margin of the field; (c) an oil-gas interface sector, in the middle of the field; (d) an external area, outside the northern gas field boundaries. The results show that positive CH{sub 4} fluxes are pervasive in all sectors and therefore, only part of the CH{sub 4} migrating from the deep oil-gas reservoirs is consumed in the soil by methanotrophic oxidation. The intensity of gas seepage seems to be controlled by subsurface geologic settings and lateral variabilities of natural gas pressure in the condensed gas field. The highest CH{sub 4} fluxes, up to {approx}14 mg m{sup -2} d{sup -1} (mean of 7.55 mg m{sup -2} d{sup -1}) with higher spatial variability

  14. Fish Habitat Improvement Projects in the Fifteenmile Creek and Trout Creek Basins of Central Oregon: Field Review and Management Recommendations.

    Energy Technology Data Exchange (ETDEWEB)

    Kauffman, J. Boone

    1993-07-01

    A field review of stream habitat improvement project sites in the lower Deschutes River Basin was conducted by riparian ecology, fisheries, and hydrology specialists. Habitat management objectives, limiting factors, project implementation, land use history, and other factors were discussed at each site. This information, in conjunction with the reviewer`s field inspections of portions of a particular habitat project, provided the basis for this report.

  15. Urbanization dramatically altered the water balances of a paddy field dominated basin in Southern China

    Directory of Open Access Journals (Sweden)

    L. Hao

    2015-02-01

    Full Text Available Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration to a large population globally. However, these benefits are declining as a result of rapid environmental and socioeconomic transformations characterized by population growth, urbanization, and climate change in many Asian countries. This case study examined the responses of streamflow and watershed water balances to the decline of rice paddy fields due to urbanization in the Qinhuai River Basin in southern China where massive industrialization has occurred in the region during the past three decades. We found that streamflow increased by 58% and evapotranspiration (ET decreased by 23% during 1986–2013 as a result of an increase in urban areas of three folds and reduction of rice paddy field by 27%. Both highflows and lowflows increased significantly by about 28% from 2002 to 2013. The increases in streamflow were consistent with the decreases in ET and leaf area index monitored by independent remote sensing MODIS data. The reduction in ET and increase in streamflow was attributed to the large cropland conversion that overwhelmed the effects of regional climate warming and climate variability. Converting traditional rice paddy fields to urban use dramatically altered land surface conditions from a water-dominated to a human-dominated landscape, and thus was considered as one of the extreme types of contemporary hydrologic disturbances. The ongoing large-scale urbanization in the rice paddy-dominated regions in the humid southern China, and East Asia, will likely elevate stormflow volume, aggravate flood risks, and intensify urban heat island effects. Understanding the linkage between land use change and changes in hydrological processes is essential for better management of urbanizing watersheds.

  16. Application of 3 D seismic technology in Puesto Hernandez field, Neuquen Basin, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Groba, C.; Mendoza, E.; Musri, D.; Quinteros, J.; Sosa, H.

    1998-07-01

    Puesto Hernandez field, in the Neuquen Basin, Argentina, provides an excellent opportunity to assess the effects of modern 3D Seismic technologies on mature field-development strategies. Perez Company S A is conducting a waterflood project in the Avile Member of the Agrio Formation. A 3D seismic survey conducted in late 1995 resulted in an improved geological model of the Avile Member. This model allowed a better definition of the reservoir limits and structure and explained the presence of water oil contacts where earlier interpretations failed to predict them. A seismic attribute analysis enhanced the areal distribution of h{theta} and helped to detect the location of a gas cap. Using this information an outpost well as driller which revealed a new oil production zone where two horizontal well are now in production. This geological model was input in a numerical simulation model that helped to characterize faults as sealing, partial sealing and channelling, which explained the existence of early breakthroughs and yielded improvements in the design of the injection patterns. (author)

  17. Multivariate statisticalmethods applied to interpretation of saturated biomarkers (Velebit oil field, SE Pannonian Basin, Serbia

    Directory of Open Access Journals (Sweden)

    TATJANA SOLEVIC

    2006-07-01

    Full Text Available Twenty-five crude oils originating from the Velebit oil field (SE Pannonian Basin, the most important oil field in Serbia, were investigated. Saturated biomarkers (n-alkanes, isoprenoids, steranes and triterpanes were analyzed by gas chromatography-mass spectrometry (GC-MS. Based on the distribution and abundance of these compounds, a large number of source and maturation parameters were calculated, particularly those most often used in correlation studies of oils. The examined samples were classified according to their origin and level of thermal maturity using factor, cluster and discriminant analyses. According to the source and maturation parameters, combined factor and cluster analyses using the Ward method enabled the categorization of the investigated oils into three groups. The cluster Ward analysis was shown to be of greater susceptibility and reliability. However, in addition to the two aforementioned methods, K-Means cluster analysis and discriminant analysis were shown to be necessary for a more precise and detailed categorization in the case of a large number of samples in one group. Consequently, it was concluded that factor and cluster K-Means andWard analyses can generally be used for the interpretation of saturated biomarkers in correlation studies of oils, but the observed results have to be checked, i.e., confirmed by discriminant analysis.

  18. Drmno lignite field (Kostolac basin, Serbia: Origin and palaeoenvironmental implications from petrological and organic geochemical studies

    Directory of Open Access Journals (Sweden)

    Stojanović Ksenija

    2012-01-01

    Full Text Available The objective of the study was to determine the origin and to reconstruct the geological evolution of lignites from the Drmno field (Kostolac Basin, Serbia. For this purpose petrological and organic geochemical analyses were used. Coal from the Drmno field is typical humic coal. Peat-forming vegetation dominated by decay of resistant gymnosperm (coniferous plants, followed by prokaryotic organisms and angiosperms. Coal forming plants belonged to the gymnosperm families Taxodiaceae, Podocarpaceae, Cupressaceae, Araucariaceae, Phyllocladaceae and Pinaceae. Peatification was performed in neutral to slightly acidic, fresh water environment. Considering that organic matter of Drmno lignites was deposited at the same time, in the relatively constant climate, it could be supposed that climate probably had only small impact on peatification. Therefore, variations in compositions of macerals and biomarkers indicate changes in the water level, due to seasonal drying of the mire, which caused vegetation differences in the palaeoplant communities and changes of redox conditions (from anoxic to slightly oxic during peatification. Diagenetic transformations of the organic matter were mainly governed by microbial activity, rather than thermal alteration.

  19. Investigations About the Recording of the Palaeomagnetic Field in the Mono Basin, CA, in Siltstone from a Granitic Provenance

    Science.gov (United States)

    Liddicoat, Joseph; Coe, Robert

    2014-05-01

    For more than three decades, Reidar Lovlie did innovative laboratory and field experiments that advanced our understanding about how sediments acquire a remanent magnetization (Lovlie, 1979, and his subsequent publications about that research). The investigations we and our students have done with lacustrine sediments deposited during the late Pleistocene in the Mono Basin, CA, have benefited from those experiments. One of Lovlie's laboratory experiments that was especially useful in our investigation of the role of relative field intensity (RFI) during a rapidly changing field, the Mono Lake Excursion (MLE; Coe and Liddicoat, 1994), was his study of suspended magnetic grains in slowly curing epoxy resin as the field strength was varied (Lovlie, 1993). More recently we did comparative field and laboratory experiments with sediments from different depositional environments in the Mono Basin that help to explain the recording of the palaeomagnetic field in unweathered siltstone derived from a granitic provenance in the California Sierra Nevada. Our investigations are possible because inclination, declination, and RFI using alternating field and thermal demagnetization and intensity normalizing experiments of magnetic susceptibility (k), saturation isothermal remanent magnetization (SIRM), and anhysteretic remanent magnetization (ARM)(Lund et al., 2005) can be measured with precision for localities separated by as much as 15 kilometres using volcanic ash beds as marker horizons. In addition to making the comparison between localities in the Mono Basin that record the MLE, we have done that for a time interval following the MLE also in the Mono Basin where the palaeomagnetic directions are anomalous compared to secular variation (waveform Delta in Lund et al., 1988; Liddicoat and Coe, 2013). In that interval the RFI is nearly double the RFI during the MLE (Zimmerman et al., 2006), which again allows us to study RFI as a factor in the palaeomagnetic recording process in

  20. Building Exposure Maps Of Urban Infrastructure And Crop Fields In The Mekong River Basin

    Science.gov (United States)

    Haas, E.; Weichselbaum, J.; Gangkofner, U.; Miltzer, J.; Wali, A.

    2013-12-01

    In the frame of the Integrated Water Resources Management (IWRM) initiative for the Mekong river basin World Bank is collaborating with the Mekong River Commission and governmental organizations in Cambodia, Lao PDR, Thailand and Vietnam to build national and regional capacities for managing the risks associated with natural disasters, such as floods, flash floods and droughts. Within ‘eoworld', a joint initiative set up by ESA and World Bank to foster the use of Earth Observation (EO) for sustainable development work, a comprehensive database of elements at risk in the Lower Mekong river basin has been established by GeoVille, including urban infrastructure and crops (primarily rice paddies). In the long term, this exposure information shall be fed into an open-source multi- hazard modeling tool for risk assessment along the Mekong River, which then shall be used by national stakeholders as well as insurance and financial institutions for planning, disaster preparedness and emergency management. Earth Observation techniques can provide objective, synoptic and repetitive observations of elements at risk including buildings, infrastructure and crops. Through the fusion of satellite-based with in-situ data from field surveys and local knowledge (e.g. on building materials) features at risk can be characterised and mapped with high accuracy. Earth Observation data utilised comprise bi-weekly Envisat ASAR imagery programmed for a period of 9 months in 2011 to map the development of the rice cultivation area, identify predominant cropping systems (wet-season vs. dry season cultivation), crop cycles (single /double / triple crop per year), date of emergence/harvest and the distinction between rice planted under intensive (SRI) vs. regular rice cultivation techniques. Very High Resolution (VHR) optical data from SPOT, KOMPSAT and QuickBird were used for mapping of buildings and infrastructure, such as building footprints, residential / commercial areas, industrial

  1. Increased Oil Production and Reserves From Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, C.D.; Deo, M.D.

    1998-04-01

    The Bluebell field is productive from the Tertiary lower Green River and Colton (Wasatch) Formations of the Uinta Basin, Utah. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate beds deposited in the ancestral Lake Uinta. Wells in the Bluebell field are typically completed by perforating 40 or more beds over 1000 to 3000 vertical ft (300-900 m), then stimulating the entire interval with hydrochloric acid. This technique is often referred to as the shot gun completion. Completion techniques used in the Bluebell field were discussed in detail in the Second Annual Report (Curtice, 1996). The shot-gun technique is believed to leave many potentially productive beds damaged and/or untreated, while allowing water-bearing and low-pressure (thief) zones to communicate with the wellbore. A two-year characterization study involved detailed examination of outcrop, core, well logs, surface and subsurface fractures, produced oil-field waters, engineering parameters of the two demonstration wells, and analysis of past completion techniques and effectiveness. The study was intended to improve the geologic characterization of the producing formations and thereby develop completion techniques specific to the producing beds or facies instead of a shot gun approach to stimulating all the beds. The characterization did not identify predictable-facies or predictable-fracture trends within the vertical stratigraphic column as originally hoped. Advanced logging techniques can identify productive beds in individual wells. A field-demonstration program was developed to use cased-hole advanced logging techniques in two wells and recompletion the wells at two different scales based on the logging. The first well was going to be completed at the interval scale using a multiple stage completion technique (about 500 ft [150 m] per stage). The second well will be recompleted at the bed-scale using bridge plug and packer to isolate three or more

  2. Basin-scale Green's functions from the ambient seismic field recorded by MeSO-net stations

    Science.gov (United States)

    Viens, Loïc.; Koketsu, Kazuki; Miyake, Hiroe; Sakai, Shin'ichi; Nakagawa, Shigeki

    2016-04-01

    Seismic waves propagating through the Earth can be significantly affected by velocity structures such as sedimentary basins. We investigate the propagation characteristics of seismic waves across the Kanto basin, Japan, using Green's functions extracted from the ambient seismic field. We use two stations situated on the eastern and southern edges of the basin as virtual sources, and approximately 420 stations, which are mainly a part of the Metropolitan Seismic Observation network (MeSO-net), as receivers. Using seismometers aligned along two straight lines with the virtual sources, we find that several types of waves can be recovered, each with different sensitivities to the layers that compose the basin. We also show that after amplitude calibration, the extracted Green's functions can accurately simulate the seismic waves of two moderate Mw 4-5 shallow earthquakes that occurred close to the virtual sources. Furthermore, we find that the distribution of the 5% damped pseudovelocity response at a period of 6 s computed from the records of each event and the Green's function waveforms have similar amplification patterns. This study supports the fact that dense networks recording continuously the ambient seismic field in metropolitan areas can be used to accurately assess seismic hazard at high spatial resolution.

  3. First horizontal well opens new gas opportunities in the Sierra Chata Field Neuquen Basin-Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, C.A.; Nilson, G.J.; Acree, J.F.; Del Pino, M.A. [Devon Energy Corp., Calgary, AB (Canada); Anaya, L. [BJ Services Co. USA, Houston, TX (United States)

    2002-07-01

    This paper described the drilling activity surrounding the first horizontal re-entry gas well in the Sierra Chata field in the Neuquen basin in Argentina. In particular, a model forecast was compared with the final results. The re-entry well was originally designed to add gas reserves and to incorporate horizontal well technology to help access the thin sands with low permeability. A numeric simulation of the 1000 m horizontal well was used to predict an initial gas flow rate of 17.7 MMscfd with an estimated final recovery of 7.3 Bscf. This forecast was confirmed following the first year of production. Operational problems, however, were encountered and new solutions were needed to bring the well back on line. The use of an existing well bore saved $1 MM and improved the economics of the project. When re-entering the existing well bore, no new flow line was needed. Given the success of this first re-entry well, it was suggested that this technology can now be used for the Machiline formation which has low productivity for several reasons, including thin sands, low permeability and difficult access via vertical wells. The use of mud logs and resistivity/gamma ray logs while drilling was very important for geological control purposes. It was noted that a measurement while drilling (MWD) tool closer to the bit would have further improved the ability to stay within very thin target zones. 11 refs., 19 figs.

  4. Exposures and cancer incidence near oil fields in the Amazon basin of Ecuador.

    Science.gov (United States)

    San Sebastián, M; Armstrong, B; Córdoba, J A; Stephens, C

    2001-08-01

    To examine environmental exposure and incidence and mortality of cancer in the village of San Carlos surrounded by oil fields in the Amazon basin of Ecuador. Water samples of the local streams were analyzed for total petroleum hydrocarbons (TPHs). A preliminary list of potential cancer cases from 1989 to 1998 was prepared. Cases were compared with expected numbers of cancer morbidity and mortality registrations from a Quito reference population. Water analysis showed severe exposure to TPHs by the residents. Ten patients with cancer were diagnosed while resident in the village of San Carlos. An overall excess for all types of cancer was found in the male population (8 observed v 3.5 expected) with a risk 2.26 times higher than expected (95% confidence interval (95% CI) 0.97 to 4.46). There was an overall excess of deaths for all types of cancer (6 v 1.6 expected) among the male population 3.6 times higher than the reference population (95% CI 1.31 to 7.81). The observed excess of cancer might be associated with the pollution of the environment by toxic contaminants coming from the oil production.

  5. Paragneiss zircon geochronology and trace element geochemistry, North Qaidam HP/UHP terrane, western China

    Science.gov (United States)

    Mattinson, C.G.; Wooden, J.L.; Zhang, J.X.; Bird, D.K.

    2009-01-01

    In the southeastern part of the North Qaidam terrane, near Dulan, paragneiss hosts minor peridotite and UHP eclogite. Zircon geochronology and trace element geochemistry of three paragneiss samples (located within a ???3 km transect) indicates that eclogite-facies metamorphism resulted in variable degrees of zircon growth and recrystallization in the three samples. Inherited zircon core age groups at 1.8 and 2.5 Ga suggest that the protoliths of these rocks may have received sediments from the Yangtze or North China cratons. Mineral inclusions, depletion in HREE, and absence of negative Eu anomalies indicate that zircon U-Pb ages of 431 ?? 5 Ma and 426 ?? 4 Ma reflect eclogite-facies zircon growth in two of the samples. Ti-in-zircon thermometry results are tightly grouped at ???660 and ???600 ??C, respectively. Inclusions of metamorphic minerals, scarcity of inherited cores, and lack of isotopic or trace element inheritance demonstrate that significant new metamorphic zircon growth must have occurred. In contrast, zircon in the third sample is dominated by inherited grains, and rims show isotopic and trace element inheritance, suggesting solid-state recrystallization of detrital zircon with only minor new growth. ?? 2009 Elsevier Ltd.

  6. Age of Yingfeng rapakivi granite pluton on the north flank of Qaidam and its geological significance

    Institute of Scientific and Technical Information of China (English)

    XIAO Qinghui; LU Xinxiang; WANG Fei; SUN Yangui; WEI Xiangdong; XlNG Zuoyun

    2004-01-01

    The Yingfeng rapakivi granite on the north flank of Qaidam is a newly discovered Proterozoic rapakivi pluton in China, which was found after the discovery of Shachang rapakivi in Miyun County, Beijing and Kuandian rapakivi in Jilin Province. Yingfeng rapakivi pluton is exposed on the north side of the suture belt between Qinling-Kunlun orogenic belt and North China plate. U-Pb zircon isotopic dating and Ar-Ar isotopic dating of both hornblende and K-feldspar from the Yingfeng rapakivi granite have been conducted. The results show that the age of (1776±33)Ma at the upper intercept in Concorde diagram represents the age of formation of the pluton,whereas the age of (526 ± 281) Ma at the lower intercept and Ar-Ar mineral dating of hornblende and K-feldspar correspond to the age of a later event affecting the pluton, suggesting that Yingfeng pluton has ever been affected by strong regional Caledonian-Hercynian tectonic movement after its formation. The discovery of middle Proterozoic Yingfeng rapakivi granite provides a petrologic evidence for the timing of cratonization of both the continental crust basement in western China and the basement of the North China plate and for a rifting event taking place in the mid-Proterozoic, suggesting that an amalgamation of ancient China continents had ever happened during the "L(u) liang Movement" between the early Proterozoic and the mid-Proterozoic.

  7. Modern analogues for Miocene to Pleistocene alkali basaltic phreatomagmatic fields in the Pannonian Basin: "soft-substrate" to "combined" aquifer controlled phreatomagmatism in intraplate volcanic fields Research Article

    Science.gov (United States)

    Németh, Károly; Cronin, Shane; Haller, Miguel; Brenna, Marco; Csillag, Gabor

    2010-09-01

    The Pannonian Basin (Central Europe) hosts numerous alkali basaltic volcanic fields in an area similar to 200 000 km2. These volcanic fields were formed in an approximate time span of 8 million years producing smallvolume volcanoes typically considered to be monogenetic. Polycyclic monogenetic volcanic complexes are also common in each field however. The original morphology of volcanic landforms, especially phreatomagmatic volcanoes, is commonly modified. by erosion, commonly aided by tectonic uplift. The phreatomagmatic volcanoes eroded to the level of their sub-surface architecture expose crater to conduit filling as well as diatreme facies of pyroclastic rock assemblages. Uncertainties due to the strong erosion influenced by tectonic uplifts, fast and broad climatic changes, vegetation cover variations, and rapidly changing fluvio-lacustrine events in the past 8 million years in the Pannonian Basin have created a need to reconstruct and visualise the paleoenvironment into which the monogenetic volcanoes erupted. Here phreatomagmatic volcanic fields of the Miocene to Pleistocene western Hungarian alkali basaltic province have been selected and compared with modern phreatomagmatic fields. It has been concluded that the Auckland Volcanic Field (AVF) in New Zealand could be viewed as a prime modern analogue for the western Hungarian phreatomagmatic fields by sharing similarities in their pyroclastic successions textures such as pyroclast morphology, type, juvenile particle ratio to accidental lithics. Beside the AVF two other, morphologically more modified volcanic fields (Pali Aike, Argentina and Jeju, Korea) show similar features to the western Hungarian examples, highlighting issues such as preservation potential of pyroclastic successions of phreatomagmatic volcanoes.

  8. The petrographical and organic geochemical composition of coal from the East field, Bogovina Basin (Serbia)

    Energy Technology Data Exchange (ETDEWEB)

    Zivotic, Dragana [Faculty of Mining and Geology, University of Belgrade, Djusina 7, Belgrade (RS); Jovancicevic, Branimir; Grzetic, Ivan; Stojanovic, Ksenija [Faculty of Chemistry, University of Belgrade, Studentski trg 16, Belgrade (RS); Schwarzbauer, Jan [Institute of Geology and Geochemistry of Petroleum and Coal, Rhenish-Westphalian Technical University of Aachen, Aachen (Germany); Cvetkovic, Olga; Sajnovic, Aleksandra [Centre of Chemistry, IChTM, Studentski trg 16, Belgrade (RS); Ercegovac, Marko [Serbian Academy of Sciences and Arts, Knez Mihailova 35, Belgrade (RS)

    2010-04-01

    A petrological and organic geochemical study was performed on coal samples from the East field deposit, Bogovina Basin, Serbia. Fourteen coal samples were collected from different parts of the Main and Upper coal seams from fresh, working faces in the underground subbituminous coal mine. The Lower Miocene (?) coal of the East field is a typical humic coal with huminite, liptinite and inertinite concentrations of up to 81.4 vol.%, 16.1 vol.% and 13.5 vol.%, respectively. Densinite is the most abundant maceral with variable amounts of ulminite and gelinite. Sporinite and liptodetrinite are the most common macerals of the liptinite group. Exsudatinite was detected in the lower part of the Lower coal seam. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral matter consists mostly of clay minerals and carbonates. The mean random huminite reflectance (ulminite B) for the Main coal seam is 0.42 {+-} 0.04%Rr, and 0.41 {+-} 0.04%Rr for the Upper coal seam, which are typical for an immature to early mature stage of the organic matter. The distribution and abundance of n-alkanes and steranes indicates a significant contribution of epicuticular waxes from higher plants. High amount of phyllocladane-type diterpenoids (16{alpha}(H)-phyllocladane) suggests that coal forming plants were conifer families Taxodiaceae, Podocarpaceae, Cupressaceae, Araucariaceae, Sciadopityaceae, and Phyllocladaceae, while a higher amount of pimarane and norpimarane suggests Pinaceae, Taxodiaceae, and Cupressaceae. The pristane/phytane (Pr/Ph) ratio implies variable anaerobic to oxic conditions during sedimentation. The distribution of the hopanes detected in the Bogovina East field coal indicates an immature to early mature stage of the organic matter, which is in agreement with huminite reflectance. The high coal sulphur contents from the East field are characteristic for slightly alkaline depositional environments generated by bentonite from the basement of the Main

  9. Petroleum system and production characteristics of the Muddy (J) Sandstone (Lower Cretaceous) Wattenberg continuous gas field, Denver basin, Colorado

    Science.gov (United States)

    Higley, D.K.; Cox, D.O.; Weimer, R.J.

    2003-01-01

    Wattenberg field is a continuous-type gas accumulation. Estimated ultimate recovery from current wells is 1.27 tcf of gas from the Lower Cretaceous Muddy (J) Sandstone. Mean gas resources that have the potential to be added to these reserves in the next 30 yr are 1.09 tcf; this will be primarily through infill drilling to recover a greater percentage of gas in place and to drain areas that are isolated because of geologic compartmentalization. Greatest gas production from the Muddy (J) Sandstone in Wattenberg field occurs (1) from within the most permeable and thickest intervals of Fort Collins Member delta-front and nearshore-marine sandstones, (2) to a lesser extent from the Horsetooth Member valley-fill channel sandstones, (3) in association with a large thermal anomaly that is delineated by measured temperatures in wells and by vitrinite reflectance contours of 0.9% and greater, (4) in proximity to the bounding Mowry, Graneros, and Skull Creek shales that are the hydrocarbon source rocks and reservoir seals, and (5) between the Lafayette and Longmont right-lateral wrench fault zones (WFZs) with secondary faults that act as conduits in areas of the field. The axis of greatest gas production is north 25 to 35?? northeast, which parallels the basin axis. Recurrent movement along five right-lateral WFZs that crosscut Wattenberg field shifted the Denver basin axis to the northeast and influenced depositional and erosional patterns of the reservoir and seal intervals. Levels of thermal maturity within the Wattenberg field are anomalously high compared to other areas of the Denver basin. The Wattenberg field thermal anomaly may be due to upward movement of fluids along faults associated with probable igneous intrusions. Areas of anomalous high heat flow within the field correlate with an increased and variable gas-oil ratio.

  10. Validation of SCS CN Method for Runoff Estimation with Field Observed Regression Analysis Results in Venna Basin, Central India.

    Science.gov (United States)

    Katpatal, Y. B.; Paranjpe, S. V.; Kadu, M.

    2014-12-01

    Effective Watershed management requires authentic data of surface runoff potential for which several methods and models are in use. Generally, non availability of field data calls for techniques based on remote observations. Soil Conservation Services Curve Number (SCS CN) method is an important method which utilizes information generated from remote sensing for estimation of runoff. Several attempts have been made to validate the runoff values generated from SCS CN method by comparing the results obtained from other methods. In the present study, runoff estimation through SCS CN method has been performed using IRS LISS IV data for the Venna Basin situated in the Central India. The field data was available for Venna Basin. The Land use/land cover and soil layers have been generated for the entire watershed using the satellite data and Geographic Information System (GIS). The Venna basin have been divided into intercepted catchment and free catchment. Run off values have been estimated using field data through regression analysis. The runoff values estimated using SCS CN method have been compared with yield values generated using data collected from the tank gauge stations and data from the discharge stations. The correlation helps in validation of the results obtained from the SCS CN method and its applicability in Indian conditions. Key Words: SCS CN Method, Regression Analysis, Land Use / Land cover, Runoff, Remote Sensing, GIS.

  11. Sedimentology of the Essaouira Basin (Meskala Field) in context of regional sediment distribution patterns during upper Triassic pluvial events

    Science.gov (United States)

    Mader, Nadine K.; Redfern, Jonathan; El Ouataoui, Majid

    2017-06-01

    Upper Triassic continental clastics (TAGI: Trias Argilo-Greseux Inferieur) in the Essaouira Basin are largely restricted to the subsurface, which has limited analysis of the depositional environments and led to speculation on potential provenance of the fluvial systems. Facies analysis of core from the Meskala Field onshore Essaouira Basin is compared with tentatively time-equivalent deposits exposed in extensive outcrops in the Argana Valley, to propose a process orientated model for local versus regional sediment distribution patterns in the continuously evolving Moroccan Atlantic rift during Carnian to Norian times. The study aims to unravel the climatic overprint and improve the understanding of paleo-climatic variations along the Moroccan Atlantic margin to previously recognised Upper Triassic pluvial events. In the Essaouira Basin, four facies associations representing a progressive evolution from proximal to distal facies belts in a continental rift were established. Early ephemeral braided river systems are succeeded by a wet aeolian sandflat environment with a strong arid climatic overprint (FA1). This is followed by the onset of perennial fluvial deposits with extensive floodplain fines (FA2), accompanied by a distinct shift in fluvial style, suggesting increase in discharge and related humidity, either locally or in the catchment area. The fluvial facies transitions to a shallow lacustrine or playa lake delta environment (FA3), which exhibits cyclical abandonment. The delta is progressively overlain by a terminal playa with extensive, mottled mudstones (FA4), interpreted to present a return from cyclical humid-arid conditions to prevailing aridity in the basin. In terms of regional distribution and sediment source provenance, paleocurrent data from Carnian to Norian deposits (T5 to T8 member) in the Argana Valley suggest paleoflow focused towards the S and SW, not directed towards the Meskala area in the NW as previously suggested. A major depo

  12. The S to P convert wave from the bottom of sediment basin in the near-field seismic records

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From the near-field records of aftershocks of October 1989 and March 1991 Datong earthquakes, an extra phase between P and S arrivals is found. High-precision epicenter location shows that some of these records are obtained with the incidental angle less than the critical angle. This excludes the possibility that the extra wave phase is a refractive wave from ground surface. Particle motion analysis shows that the characteristic of the extra wave is similar to that of P wave, therefore it is very possible that the extra phase is an S to P convert wave from the bottom of sediment basin. Suppose a low velocity layer covers on a high velocity basement. Successful simulation by synthetic seismogram conforms that the extra phase is an S-P convert wave from the interface of basin bottom. Modifying the depth of interface at each ray path to match the waveform, we obtain an interface distribution in space. In this way a brief imagine of bottom could be shown, and Datong basin has a (V( shape basin bottom.

  13. Energy Balance of Irrigated Intercropping Field in the Middle Reaches of Heihe River Basin

    Institute of Scientific and Technical Information of China (English)

    WU Jinkui; DING Yongjian; WANG Genxu; SHEN Yongping; Yusuke YAMAZAKI; Jumpei KUBOTA

    2006-01-01

    Based on the experiments conducted in an irrigated intercropping field in Zhangye Oasis in the middle reaches of Heihe River basin in 2004, the characteristics of radiation budget are analyzed. Furthermore, energy balance is calculated by using Bowen-Ratio Energy Balance (BREB) method. The results show that the ratio of the absorbed radiation to the incoming short radiation in intercropping crop canopy-soil system is increasing with growing stages, from 0.81 in the initial growing stage (IGS) to 0.86 in the late growing stage (LGS). The net radiation, which is smaller in IGS, increases rapidly in the first period of the middle growing stage (MGS) and reaches the maximum value in the second period of MGS. It then somewhat decreases in LGS. The ratio of net radiation to total radiation has a similar trend with the net radiation. In the whole growing stages, latent heat flux, which takes up 70% or so of the net radiation, is the dominant item in energy balance. Sensible heat flux shares 20% of the net radiation and soil heat flux has a percentage of 10%. The characteristics of heat balance vary distinctly in different growing stages. In IGS, the ratios of latent heat flux,sensible heat flux and soil heat flux to net radiation are 44.5%, 23.8% and 31.7% respectively. In MGS, with the increasing of latent heat flux and the decreasing of sensible heat flux and soil heat flux, the ratios turn into 84.4%, 6.3% and 9.3%. In LGS, the soil heat flux maintains 0W/m2 or so, and latent heat flux and sensible heat flux take up 61.4% and 38.6% respectively. The energy balance also shows an obvious daily variation characteristic.

  14. Genesis mechanism of the Sinian-Cambrian reservoirs in the Anyue Gas Field, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Zhou Jingao

    2015-03-01

    Full Text Available The Lower Cambrian Longwangmiao Fm, the 4th and 2nd members of the Sinian Dengying Fm are the three major gas layers in the Anyue Gas Field of the Sichuan Basin. Their main characteristics and genesis mechanism were investigated, and the following three findings were obtained. First, according to sedimentary microfacies, lithology and porosity, the Longwangmiao Fm is identified as fractured-vuggy dolomite reservoir of grain shoal facies, the 4th member of the Dengying Fm as fractured-vuggy (cavernous dolomite reservoir of cyanobacteria mound beach facies, and the 2nd member of the Dengying Fm as fractured-vuggy dolomite reservoirs of cyanobacteria mound beach facies. Second, the Longwangmiao Fm is mainly grain dolomite, with dissolution pores and vugs as major reservoir space, at an average porosity of 4.24% and an average thickness of 36 m. The 4th member of the Dengying Fm made up of cyanobacteria dolomite has dissolution pores, vugs and caverns as major reservoir space with an average porosity of 3.22% and an average thickness of 70 m. The 2nd member of the Dengying Fm composed of cyanobacteria dolomite has fractures and vugs as major reservoir space with an average porosity of 3.34% and an average thickness of 80 m. Third, those reservoirs experienced multiple evolutionary stages including porosity development, hydrothermal mineral filling, asphalt filling etc. Penecontemporaneous dissolution and supergene karstification are the key factors controlling the formation of the reservoir space and the evolution models of the reservoirs were figured out.

  15. Molecular organic geochemistry of the Apiay field in the Llanos basin, Colombia

    Science.gov (United States)

    Cortes, J. E.; Niño, J. E.; Polo, J. A.; Tobo, A. G.; Gonzalez, C.; Siachoque, S. C.

    2013-11-01

    The bulk properties and molecular organic geochemical composition for crude oils from the Apiay, Suria and Reforma/Libertad producer areas, which integrate the Apiay field located in the southwest area of the Llanos Basin in Colombia were analyzed by gas chromatography (GC/FID), isotopic analysis and gas chromatography/mass spectrometry (GC/MS) analysis. The main producing intervals in the Apiay field are known as the K2 and K1 units of the Guadalupe Formation, a thick siliciclastic sequence deposited during the Upper Cretaceous to Upper Eocene in a fluvial and transitional marine system. The crude oils analyzed are paraffinic, with saturate fraction >60%, the δ13C isotopic composition ranging from -26.19 to -25.62 for the saturated fraction, -25.84 to -24.02 for the aromatic fraction, and canonical variable (C.V.) 1.5, low ≈ high molecular weigh hydrocarbons indicating an input of algal/microbial organic matter with a significant input of terrigenous matter (higher plants). Branched/Cyclic biomarkers, previously separated from n-alkanes by silicalite/ZSM-5 (S-115), were analyzed using SIM-GC/MS. Samples from the Apiay area showed higher concentration of tricyclic terpanes than samples from Suria and Reforma-Libertad, respectively, which suggests an early diagenetic influence of marine saline water, consistent with early generation from marine organic matter. However, the presence of a great suit of sesquiterpanes and diterpanes in all samples confirming an angiosperm input. Ts/Ts + Tm falls in the range of 0.25-0.66, all samples present gammacerane, C31-Hopane isomerization index ranged between 0.50 and 0.71. A predominance of C29 over C27 and C28-steranes in the Apiay area indicates terrigenous source rock for most of the samples, however samples from the Reforma-Libertad and Apiay areas show mixing characteristics of crude oils originated from marine and terrigenous sources. Diasteranes are higher than regular steranes, which predicts a siliciclastic

  16. An Integrated Rock Typing Approach for Unraveling the Reservoir Heterogeneity of Tight Sands in the Whicher Range Field of Perth Basin, Western Australia

    DEFF Research Database (Denmark)

    Ilkhchi, Rahim Kadkhodaie; Rezaee, Reza; Harami, Reza Moussavi;

    2014-01-01

    Tight gas sands in Whicher Range Field of Perth Basin show large heterogeneity in reservoir characteristics and production behavior related to depositional and diagenetic features. Diagenetic events (compaction and cementation) have severely affected the pore system. In order to investigate...

  17. Discovery of Coesite in the North Qaidam Caledonian Ultrahigh-High Pressure (UHP-HP) Metamorphic Belt in the NE Qinghai-Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    YANG Jingsui; ShI Rendeng; SONG Shuguang; XU Zhiqin; LIU Fulai; S. MARUYAMA; J. G. LIOU; ZHANG Jianxin; WU Cailai; LI Haibing

    2001-01-01

    @@ Coesite was discovered as inclusions in zircon separates from paragneiss associated with a large eclogite body in the North Belt of the Qaidam UHP terrane on the Chinese New Year of 2001 by Laser Raman Spectrometer at Tokyo Institute of Technology. Some graphite inclusions also found.

  18. Geothermal field and thermotectonic evolution in Southern South Yellow Sea Basin

    Institute of Scientific and Technical Information of China (English)

    YANG Shuchun; HU Shengbiao; CAI Dongsheng; FENG Xiaojie; GAO Le; LU Jingmei

    2003-01-01

    Based on the available borehole temperature data and measurements of thermal conductivities on 10 core samples in the Southern South Yellow Sea Basin, 8 heat flow values are obtained. The results show that the mean values of temperature gradient and heat flow are 28.6℃/km and 69 mW/m2, respectively. The thermal history reconstruction from the inversion of vitrinite reflectance data, using the temperature-gradient method, indicates that the highest paleo-heat flow occurred at the end of the Mesozoic, and then the basin began to cool to present day. Tectonic subsidence analysis shows that the basin experienced at least four episodes of quick subsidence since the late Paleozoic and that the tectonic evolution was quite strong and complex.

  19. Identification Of Hydrocarbon Regions In Southern Niger Delta Basin Of Nigeria From Potential Field Data

    Directory of Open Access Journals (Sweden)

    Eke

    2015-08-01

    Full Text Available Potential hydrocarbon regions in the southern region of the Niger delta Basin of Nigeria have been identified from gravity and magnetic data. The enhanced residual data obtained from least square analysis method was interpreted by inverse and forward modeling techniques using Potent-3D software. The results reveal potential hydrocarbon environment at depths of between 1000 m to 3 500 m from the gravity data and depths of 2183 m to 4385 m from the magnetic data. The identified structures trend in NS EW and NE-SW directions of the basin.

  20. A multi-stage 3-D stress field modelling approach exemplified in the Bavarian Molasse Basin

    Science.gov (United States)

    Ziegler, Moritz O.; Heidbach, Oliver; Reinecker, John; Przybycin, Anna M.; Scheck-Wenderoth, Magdalena

    2016-09-01

    The knowledge of the contemporary in situ stress state is a key issue for safe and sustainable subsurface engineering. However, information on the orientation and magnitudes of the stress state is limited and often not available for the areas of interest. Therefore 3-D geomechanical-numerical modelling is used to estimate the in situ stress state and the distance of faults from failure for application in subsurface engineering. The main challenge in this approach is to bridge the gap in scale between the widely scattered data used for calibration of the model and the high resolution in the target area required for the application. We present a multi-stage 3-D geomechanical-numerical approach which provides a state-of-the-art model of the stress field for a reservoir-scale area from widely scattered data records. Therefore, we first use a large-scale regional model which is calibrated by available stress data and provides the full 3-D stress tensor at discrete points in the entire model volume. The modelled stress state is used subsequently for the calibration of a smaller-scale model located within the large-scale model in an area without any observed stress data records. We exemplify this approach with two-stages for the area around Munich in the German Molasse Basin. As an example of application, we estimate the scalar values for slip tendency and fracture potential from the model results as measures for the criticality of fault reactivation in the reservoir-scale model. The modelling results show that variations due to uncertainties in the input data are mainly introduced by the uncertain material properties and missing SHmax magnitude estimates needed for a more reliable model calibration. This leads to the conclusion that at this stage the model's reliability depends only on the amount and quality of available stress information rather than on the modelling technique itself or on local details of the model geometry. Any improvements in modelling and increases

  1. FITESC - Field Investigation Team for severe earthquakes in Europe and the Mediterranean basin

    Science.gov (United States)

    Cecic, I.; Fitesc Preparatory Group

    2003-04-01

    The formation of the Field Investigation Team of the European Seismological Commission (FITESC) was endorsed by a resolution passed at the XXVIII General Assembly of the ESC at Genoa in September 2002. The idea of the team has induced great interest not only among seismologists, but also geologists, civil engineers and insurance companies. FITESC is a multinational and multidisciplinary team of experts that would, in the case of a damaging earthquake in Europe or the Mediterranean basin, go to the epicentral area and collect high-quality seismological data. The objectives of the team are the following: 1) To map the intensity and damage distributions after future large earthquakes in Europe (using EMS-98), principally from a seismological perspective. 2) To assist local institutes in this task, in cases where such help is needed. 3) To gather macroseismic data in a consistent way from earthquake to earthquake, and to make these data generally available. 4) To ensure that such surveys are carried out under the auspices of a permanent international body (ESC) with responsibility to the whole seismological committee (in contrast to the present situation where such missions are responsible only to a few sponsors). The long-term goal would be a database of intensity information for European earthquakes, which would be a valuable resource for seismic risk studies, and for assessing the likely effects of future large earthquakes. These data would be made freely available on the Internet. As the first step the team will start with macroseismic data only, but the idea is to make the scope of the activities wider, as there are several types of data that can be collected in this way. The list of the experts is prepared (in January 2003 there are 62 team members), along with all information necessary to launch the mission in the shortest possible time. A number of possibilities are being explored at the moment in order to provide long-term financial support outside of existing

  2. The characteristics and sources of natural gases from Ordovician weath-ered crust reservoirs in the Central Gas Field in the Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    LI Xianqing; HU Guoyi; LI Jian; HOU Dujie; DONG Peng; SONG Zhihong; YANG Yunfeng

    2008-01-01

    The Central Gas Field is a famous large-sized gas field in the Ordos Basin of China. However, identification of main gas sources of the Ordovician reservoirs in this gas field remains puzzling. On the basis of a lot of geochemical data and geological research on natural gases, the characteristics and sources of natural gases from Ordovician weathered crust reservoirs in the Central Gas Field in the Ordos Basin were studied. The results indicated that natural gases from Ordovician weathered crust reservoirs in the Central Gas Field in the Ordos Basin have similar chemical and isotopic com-positions to highly mature and over-mature dry gases. Both coal-derived gases and oil-type gases coexist in the Central Gas Field in the Ordos Basin. The former was derived mainly from Carboniferous-Permian coal measures and the latter from Lower Paleozoic marine carbonates. It is suggested that coal-derived gases occur in the eastern part of the Central Gas Field while oil-type gases may be pro-duced mainly in the northern, western and southern parts of the Central Gas Field in the Ordos Basin.

  3. Gravity field over the Sea of Galilee: Evidence for a composite basin along a transform fault

    Science.gov (United States)

    Ben-Avraham, Zvi; ten Brink, Uri; Bell, Robin; Reznikov, Margaret

    1996-01-01

    The Sea of Galilee (Lake Kinneret) is located at the northern portion of the Kinneret-Bet Shean basin, in the northern Dead Sea transform. Three hundred kilometers of continuous marine gravity data were collected in the lake and integrated with land gravity data to a distance of more than 20 km around the lake. Analyses of the gravity data resulted in a free-air anomaly map, a variable density Bouguer anomaly map, and a horizontal first derivative map of the Bouguer anomaly. These maps, together with gravity models of profiles across the lake and the area south of it, were used to infer the geometry of the basins in this region and the main faults of the transform system. The Sea of Galilee can be divided into two units. The southern half is a pull-apart that extends to the Kinarot Valley, south of the lake, whereas the northern half was formed by rotational opening and transverse normal faults. The deepest part of the basinal area is located well south of the deepest bathymetric depression. This implies that the northeastern part of the lake, where the bathymetry is the deepest, is a young feature that is actively subsiding now. The pull-apart basin is almost symmetrical in the southern part of the lake and in the Kinarot Valley south of the lake. This suggests that the basin here is bounded by strike-slip faults on both sides. The eastern boundary fault extends to the northern part of the lake, while the western fault does not cross the northern part. The main factor controlling the structural complexity of this area is the interaction of the Dead Sea transform with a subperpendicular fault system and rotated blocks.

  4. Diagenesis, provenance and reservoir quality of Triassic TAGI sandstones from Ourhoud field, Berkine (Ghadames) Basin, Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, C.; Arribas, J.; Tortosa, A. [Universidad Complutense de Madrid, (Spain). Departamento de Petrologia y Geoquimica; Kalin, O. [Universidad Complutense, Madrid (Spain). Departamento de Paleontologia

    2002-02-01

    The Triassic TAGI (Trias Argilo-Greseux Inferieur) fluvial sandstones are the main oil reservoirs in the Berkine Basin, Algeria. Nonetheless, their provenance and diagenesis, and their impact on reservoir quality, are virtually unknown. Samples from the Ourhoud field, representing the Lower, Middle and Upper TAGI subunits, were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower TAGI sandstones have an average framework composition of Q{sub 98.3}F{sub 0.6}R{sub 1.1} and 95% of the quartz grains are monocrystalline. By contrast, the Middle-Upper TAGI sandstones have an average framework composition of Q{sub 88.3}F{sub 9.8}R{sub 1.9} and 79% of the quartz grains are monocrystalline. The Lower TAGI quartz arenites derived from Paleozoic siliclastic rocks, whereas the Middle-Upper TAGI subarkoses originated mainly from metamorphic terrains. This change in provenance is a potential criterion for correlation within the TAGI. Also, this change has contributed to the significantly different diagenetic paths followed by the Lower TAGI quartz arenites and the Middle-Upper TAGI subarkoses. Grain-coating illitic clays are abundant in the Lower TAGI, where they exert a critical control on reservoir quality. These clays are interpreted as pedogenic and/or infiltrated in origin and to have had, in part, smectitic precursors. Shallow burial Fe-dolomite cementation was favored in the downthrown block of the field-bounding fault, where it contributed to the poor reservoir quality. Magnesite-siderite cements are multiphase. The earliest generation is composed of Fe-rich magnesite that precipitated during shallow burial from hypersaline fluids with high Mg/Ca ratios, probably refluxed residual brines associated with the Liassic evaporites. Later magnesite-siderite generations precipitated during deeper burial from waters with progressively higher Fe/Mg ratios. Authigenic vermicular kaolin largely consists of dickite that replaced previously

  5. Peat swamps at Giral lignite field of Barmer basin, Rajasthan,Western India: understanding the evolution through petrological modelling

    Institute of Scientific and Technical Information of China (English)

    Prakash K.Singh; P.K.Rajak; M.P.Singh; V.K.Singh; A.S.Naik; Alok K.Singh

    2016-01-01

    The lignite samples collected from Giral lignite field of Barmer basin have been subjected to petrological investigation.The data generated has been discussed to understand the evolution of the paleomires of these lignites.The present study reveals that these low rank C coals are chiefly composed of huminite group macerals,mainly telohuminite and detrohuminite,while liptinite and inertinite group macerals occur in subordinate amounts.Not much variation in the maceral composition from Seam-I to Seam-Ⅷ has been observed.Barmer lignites are characterized by a very high GI (>10) and moderate TPI indicating topogenous mire in the basin which was permanently flooded.The GI and TPI values and the petrography-based facies critical models indicate that these lignites originated mostly under wet forest swamp to clastic marsh having telmatic to limno-telmatic conditions with a moderate rate of subsidence and a very slow fall in ground water table.Further,the GWI and VI values are suggestive of mesotrophic to rheotrophic hydrological conditions having the dominance of herbaceous to marginal aquatic vegetation.There were spells of periodic drowning of peat especially during the formation of Seam-Ⅶ.Moderately high concentration of calcium in these lignites along with the presence of framboidal pyrite indicate enhanced sulphate-reducing bacterial activity present in carbonate and sulphate-rich waters in the basin during peat formation.

  6. Dipolar geomagnetic field and low orbital obliquity during the last two billion years: Evidence from paleomagnetism of evaporite basins

    Science.gov (United States)

    Evans, D. A.

    2006-05-01

    Paleomagnetism of climatically sensitive sedimentary rock types, such as glacial deposits and evaporites, can test the uniformitarianism of ancient geomagnetic fields and paleoclimatic zones. Precambrian glacial deposits laid down in near-equatorial paleomagnetic latitudes indicate a paleoclimatic paradox that can be explained either by Snowball Earth episodes, or high orbital obliquity, or dramatically non-uniformitarian geomagnetic fields. Here I present the first global paleomagnetic compilation of the Earth's entire basin-scale evaporite record. Evaporation exceeds precipitation in today's subtropical desert belts, generally within a zone of 15-35° from the equator. Assuming a geocentric axial dipole (GAD) magnetic field for Cenozoic- Mesozoic time, evaporite basins of the past 250 Myr have a volume-weighted mean paleolatitude of 23±4°, also squarely within the subtropics. Carboniferous-Permian evaporites have an indistinguishable weighted-mean paleolatitude of 22±4°, which does not change significantly when recently hypothesized octupolar field components are included in the calculations. Early Paleozoic (including late Ediacaran) evaporites are lower-latitude (weighted mean 10±5°), but detailed analyses of individual examples show this cannot be attributed solely to nondipolar field components or sedimentary inclination biases; the cause may be due to particular paleogeographic effects on regional tropical climates, or incomplete sampling by the paleomagnetic data. Proterozoic (pre-Ediacaran) evaporite basins have a volume- weighted mean inclination of 33±4°, which would correspond to a mean paleolatitude of 18±3° for a pure GAD field. This latter mean is indistinguishable, within error, from the Cenozoic-Mesozoic mean and demonstrates the success of the GAD model as a first-order description of the geomagnetic field for the last two billion years. Also, general circulation climate models of a high-obliquity Earth predict either no strong zonal

  7. Origin and formation of neck in a basin landform: Examples from the Camargo volcanic field, Chihuahua (México)

    Science.gov (United States)

    Aranda-Gómez, José Jorge; Housh, Todd B.; Luhr, James F.; Noyola-Medrano, Cristina; Rojas-Beltrán, Marco Antonio

    2010-11-01

    The term "neck in a basin" (NIB) landform is proposed for volcanic structures characterized by nearly circular to elliptical open basins, located near the headwater of small streams or drainages, which contain small volcanic necks and/or erosion remnants of one (or more) cinder cones. NIB landforms are typically 400-1000 m in diameter and 30-100 m deep and are invariably surrounded by steep walls cut into one or more basaltic lava flows. NIB landforms lack evidence for a primary volcanogenic origin through either collapse or youthful eruptive activity. In the Pliocene portion (4 - 2 Ma) of the Plio-Quaternary Camargo volcanic field of Chihuahua (México), they are relatively numerous and are best developed at the margins of a gently sloping (3-5°) basaltic lava plateau and near major fault scarps. Mature NIB landforms have ring-like circular drainage patterns and central elevations marked by small volcanic necks and associated radial dikes intruded into basaltic scoria-fall and /or agglutinate deposits. We interpret NIB landforms to be erosional in origin. They develop where a cinder cone is surrounded by one or more sheet-like lava flows from one or more separate subsequent vents. Once eruptive activity ceases at the younger volcano(es), fluvial erosion gradually produces a ring-like drainage pattern along the contact between the lava and the older cinder cone. As a response to a marked contrast in resistance to erosion between lava flows and unconsolidated or poorly lithified pyroclastic deposits, the older cinder cone is preferentially eroded. In this manner, a ring-shaped, steep sided erosional basin, preformed by the scoria cone, is produced; eventually fluvial erosion exposes the central neck and dikes. The volume, relief, and age of the volcanic field are key factors in the formation and preservation of a NIB landform. They form in volcanic fields where lava emissions are sufficiently vigorous to engulf earlier cinder cones. Relief and associated high rates

  8. FIELD IMPLEMENTATION PLAN FOR A WILLISTON BASIN BRINE EXTRACTION AND STORAGE TEST

    Energy Technology Data Exchange (ETDEWEB)

    Hamling, John; Klapperich, Ryan; Stepan, Daniel; Sorensen, James; Pekot, Lawrence; Peck, Wesley; Jacobson, Lonny; Bosshart, Nicholas; Hurley, John; Wilson, William; Kurz, Marc; Burnison, Shaughn; Salako, Olarinre; Musich, Mark; Botnen, Barry; Kalenze, Nicholas; Ayash, Scott; Ge, Jun; Jiang, Tao; Dalkhaa, Chantsalmaa; Oster, Benjamin; Peterson, Kyle; Feole, Ian; Gorecki, Charles; Steadman, Edward

    2016-03-31

    The Energy & Environmental Research Center (EERC) successfully completed all technical work of Phase I, including development of a field implementation plan (FIP) for a brine extraction and storage test (BEST) in the North Dakota portion of the Williston Basin. This implementation plan was commissioned by the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) as a proxy for managing formation pressure plumes and measuring/monitoring the movement of differential pressure and CO2 plumes in the subsurface for future saline CO2 storage projects. BEST comprises the demonstration and validation of active reservoir management (ARM) strategies and extracted brine treatment technologies. Two prospective commercial brine injection sites were evaluated for BEST to satisfy DOE’s goals. Ultimately, an active saltwater disposal (SWD) site, Johnsons Corner, was selected because it possesses an ideal combination of key factors making it uniquely suited to host BEST. This site is located in western North Dakota and operated by Nuverra Environmental Solutions (Nuverra), a national leader in brine handling, treatment, and injection. An integrated management approach was used to incorporate local and regional geologic characterization activities with geologic and simulation models, inform a monitoring, verification, and accounting (MVA) plan, and to conduct a risk assessment. This approach was used to design a FIP for an ARM schema and an extracted brine treatment technology test bed facility. The FIP leverages an existing pressure plume generated by two commercial SWD wells. These wells, in conjunction with a new brine extraction well, will be used to conduct the ARM schema. Results of these tests will be quantified based on their impact on the performance of the existing SWD wells and the surrounding reservoir system. Extracted brine will be injected into an underlying deep saline formation through a new injection well. The locations of proposed

  9. Water-soluble organic aerosol in the Los Angeles Basin and outflow regions: Airborne and ground measurements during the 2010 CalNex field campaign

    OpenAIRE

    Duong, Hanh T.; Sorooshian, Armin; Craven, Jill S.; Hersey, Scott P.; Metcalf, Andrew R.; Zhang, Xiaolu; Weber, Rodney J.; Jonsson, Haflidi; Flagan, Richard C.; Seinfeld, John H.

    2011-01-01

    A particle‐into‐liquid sampler coupled to a total organic carbon analyzer (PILS‐TOC) quantified particulate water‐soluble organic carbon (WSOC) mass concentrations during the May 2010 deployment of the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter in the CalNex field study. WSOC data collected during 16 flights provide the first spatiotemporal maps of WSOC in the San Joaquin Valley, Los Angeles Basin, and outflow regions of the Basin. WSOC w...

  10. Variations in isotopic compositions of chlorine in evaporation-controlled salt lake brines of Qaidam Basin, China

    Digital Repository Service at National Institute of Oceanography (India)

    Xiao, Ying-kai; Liu, Wei-guo; Zhou, Y.M.; Wang, Yun-hui; Shirodkar, P.V.

    The variations in the isotopic compositions of chlorine in evaporation-controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs sub(2) Cl sup(+) ion by thermal ionization...

  11. VARIATIONS IN ISOTOPIC COMPOSITIONS OF CHLORINE IN EVAPORATION-CONTROLLED SALT LAKE BRINES OF QAIDAM BASIN,CHINA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The variations in the isotopic compositions of chlorine in evaporation-controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs2Cl+ ion by thermal ionization mass spectrometry. The results showed that variation in δ37Cl values in these evaporation-controlled brines are attributable to evaporation of brine accompanied by the deposition of saline minerals. The isotopic fractionation of chlorine between the deposited saline mineral and the co-existing brine caused the variation of δ37Cl values in the brine. In general the isotopic fractionation of chlorine in nature indicates enrichment of 37Cl in the solid phase relative to 35Cl. The reverse isotopic fractionation of chlorine in which 35Cl is enriched in the solid phase, was observed to some extent during quick deposition under laboratory conditions as well as in nature. The mechanism of isotopic fractionation of chlorine during evaporation deposition was studied.

  12. Geomorphic and lithologic characteristics of Wadi Feiran basin, southern Sinai, Egypt, using remote sensing and field investigations

    Indian Academy of Sciences (India)

    Ayman A Ahmed; Mohamed Abdelkareem; Asran M Asran; Tawfig M Mahran

    2017-08-01

    Wadi Feiran is an important drainage basin in southern Sinai Peninsula covering an area of about 1785 km2, its streams drain into the Gulf of Suez crossing variety of rocks and sedimentary units varied in age from Precambrian to Quaternary. Field investigations, geographic information systems (GIS) and remote sensing studies including Landsat-7 ETM+, Radarsat-1, and SRTM DEM were integrated to reveal its lithologic, geologic and geomorphic features. Besides the field investigations, rock units including basement and pre- and syn-rift sedimentary units were discriminated using band ratios and principal component analysis techniques (PCA). Such techniques revealed that the crystalline rocks covering W. Feiran are unaltered rocks lacking OH-bearing minerals. Radar data successfully displayed the structures and geomorphic features related to topography. Moreover, the techniques allowed the extraction of the dyke-like structures along faults and shear zones. This also characterized the topographic variations through analysis of the shaded terrain and the altitudinal profiles. The results of data integration, lineament analysis and lineament density maps revealed that the structural grain in the present study has four different trends: N20–45E, N30–45W, N–S and E–W. Based on analysis of radar data and geomorphic indices, W. Feiran is an asymmetrical basin, its left side occupies ∼34% of the total area that leads to a supposedly massive tilt towards the south which caused the southwestward slope.

  13. Geomorphic and lithologic characteristics of Wadi Feiran basin, southern Sinai, Egypt, using remote sensing and field investigations

    Science.gov (United States)

    Ahmed, Ayman A.; Abdelkareem, Mohamed; Asran, Asran M.; Mahran, Tawfig M.

    2017-08-01

    Wadi Feiran is an important drainage basin in southern Sinai Peninsula covering an area of about 1785 km2, its streams drain into the Gulf of Suez crossing variety of rocks and sedimentary units varied in age from Precambrian to Quaternary. Field investigations, geographic information systems (GIS) and remote sensing studies including Landsat-7 ETM+, Radarsat-1, and SRTM DEM were integrated to reveal its lithologic, geologic and geomorphic features. Besides the field investigations, rock units including basement and pre- and syn-rift sedimentary units were discriminated using band ratios and principal component analysis techniques (PCA). Such techniques revealed that the crystalline rocks covering W. Feiran are unaltered rocks lacking OH-bearing minerals. Radar data successfully displayed the structures and geomorphic features related to topography. Moreover, the techniques allowed the extraction of the dyke-like structures along faults and shear zones. This also characterized the topographic variations through analysis of the shaded terrain and the altitudinal profiles. The results of data integration, lineament analysis and lineament density maps revealed that the structural grain in the present study has four different trends: N20-45E, N30-45W, N-S and E-W. Based on analysis of radar data and geomorphic indices, W. Feiran is an asymmetrical basin, its left side occupies ˜ 34% of the total area that leads to a supposedly massive tilt towards the south which caused the southwestward slope.

  14. Three-dimensional approach to understanding the relationship between the Plio–Quaternary stress field and tectonic inversion in the Triassic Cuyo Basin, Argentina

    Directory of Open Access Journals (Sweden)

    L. Giambiagi

    2015-06-01

    Full Text Available The Cacheuta sub-basin of the Triassic Cuyo Basin is an example of rift basin inversion contemporaneous to the advance of the Andean thrust front, during the Plio–Quaternary. This basin is one of the most important sedimentary basins in a much larger Triassic NNW-trending depositional system along the southwestern margin of the Pangea supercontinent. The amount and structural style of inversion is provided in this paper by a three-dimensional approach to the relationship between inversion of rift-related structures and spatial variations in late Cenozoic stress fields. The Plio–Quaternary stress field exhibits important N–S variations in the foreland area of the southern Central Andes, between 33 and 34° S, with a southward gradual change from pure compression, with σ1 and σ2 being horizontal, to a strike-slip type stress field, with σ2 being vertical. We present a 3-D approach for studying the tectonic inversion of the sub-basin master fault associated with strike-slip–reverse to strike-slip faulting stress regimes. We suggest that the inversion of Triassic extensional structures, striking NNW to WNW, occurred during the Plio–Pleistocene in those areas with strike-slip–reverse to strike-slip faulting stress regime, while in the reverse faulting stress regime domain they remain fossilized. Our example demonstrates the impact of the stress regime on the reactivation pattern along the faults.

  15. Three-dimensional approach to understanding the relationship between the Plio-Quaternary stress field and tectonic inversion in the Triassic Cuyo Basin, Argentina

    Directory of Open Access Journals (Sweden)

    L. Giambiagi

    2015-01-01

    Full Text Available The Cacheuta sub-basin of the Triassic Cuyo Basin is an example of rift basin inversion contemporaneous to the advance of the Andean thrust front, during the Plio-Quaternary. This basin is one of the most important sedimentary basins in a much larger Triassic NNW-trending depositional system along the southwestern margin of the Pangea supercontinent. The amount and structural style of inversion is provided in this paper by three-dimensional insights into the relationship between inversion of rift-related structures and spatial variations in late Cenozoic stress fields. The Plio-Quaternary stress field exhibits important N–S variations in the foreland area of the Southern Central Andes, between 33 and 34° S, with a southward gradually change from pure compression with σ1 and σ2 being horizontal, to a strike-slip type stress field with σ2 being vertical. We present a 3-D approach for studying the tectonic inversion of the sub-basin master fault associated with strike-slip/reverse to strike-slip faulting stress regimes. We suggest that the inversion of Triassic extensional structures, striking NNW to WNW, occurred during the Plio–Pleistocene in those areas with strike-slip/reverse to strike-slip faulting stress regime, while in the reverse faulting stress regime domain, they remain fossilized. Our example demonstrates the impact of the stress regime on the reactivation pattern along the faults.

  16. Principal component analysis of a river basin discharge and precipitation anomaly fields associated with the global circulation

    Science.gov (United States)

    Pandžić, K.; Trninić, D.

    1992-03-01

    The relation between mesoscale (the Kupa river catchment area, Yugoslavia) discharge and precipitation field anomalies and macroscale (European-Northern Atlantic Region) surface pressure anomalies is considered. For this purpose the principal component analysis (PCA) technique has been applied. Mesoscale monthly discharge values for 25 stream flow measurement stations, precipitation and the Palmer 'drought index' data for 18 weather stations as well as the macroscale surface pressure for 12 × 19 grid points have been used. All refer to the period 1961-1980. Two principal components (PCs) are the most significant for each mesoscale field, which describe more than 85% of total field variance. In addition to a significant correlation indicated between mesoscale discharge and precipitation anomaly and the Palmer 'drought index' PCs, five space anomaly patterns were established for each field. A pattern of the macroscale surface pressure anomaly field corresponds to each of these patterns. Thus, an interpretation of the discharge anomaly field in the Kupa river basin in terms of macrocirculation is achieved.

  17. Distribution and geochemical characterization of coalbed gases at excavation fields at natural analogue site area Velenje Basin, Slovenia

    Science.gov (United States)

    Kanduč, Tjaša; Žigon, Stojan; Grassa, Fausto; Sedlar, Jerneja; Zadnik, Ivo; Zavšek, Simon

    2016-04-01

    Unconventional gas resources, including coal bed methane and shale gas, are a growing part of the global energy mix, which has changed the economic and strategic picture for gas consuming and producing countries, including the USA, China and Australia that, together are responsible for around half the currently recoverable unconventional gas resources. However, CBM production was often hindered by low permeability and mineralization in cleats and fractures, necessitating the development of cost effective horizontal drilling and completion techniques. Geochemical and isotopic monitoring of coalbed gases at excavation fields in Velenje Basin started in year 2000, with the aim to obtain better insights into the origin of coalbed gases. Results from active excavation fields in the mining areas Pesje and Preloge in the year period 2014-2015 are presented in this study. Composition and isotopic composition of coalbed gases were determined with mass - spectrometric methods. The chemical (methane, carbon dioxide, nitrogen) and isotopic composition of carbon in methane and carbon dioxide in the Velenje Basin vary and depend on the composition of the source of coalbed gas before excavation, advancement of the working face, depth of the longwall face, pre-mining activity and newly mined activity. The basic gas components determined in excavation fields are carbon dioxide and methane. Knowledge of the stable isotope geochemistry of coal bed and shale gas and the related production water is essential to determine not only gas origins but also the dominant methanogenic pathway in the case of microbial gas. Concentrations of methane at active excavation fields are changing from 1.8 to 63.9 %, concentrations of carbon dioxide are changing from 36.1 to 98.2% and CDMI (Carbon Dioxide Methane Index) index from 0.2 to 100 %. Isotopic composition of carbon dioxide is changing from -11.0 to -1.9‰ , isotopic composition of methane from -71.8 to -43.3‰ , isotopic composition of

  18. Changes in Soil Physicochemical Properties Following Land Use Change from Paddy Fields to Greenhouse and Upland Fields in the Southeastern Basin of Dianchi Lake, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    N.MORITSUKA; T.NISHIKAWA; S.YAMAMOTO; N.MATSUI; H.INOUE; LI Kun-Zhi; T.INAMURA

    2013-01-01

    Paddy fields in the southeastern basin of Dianchi Lake have rapidly changed to greenhouses since 1999.A total of 61 surface soil samples,including 43 greenhouse soils,12 upland soils,and 6 paddy soils,were collected from a flat lowland area mainly used for agricultural production fields in the southeastern basin of Dianchi Lake.Analyses of the soil samples indicated that the greenhouse soils were characterized by a lower organic matter content,lower pH,and higher soluble nutrients than the paddy soils in the area.The lower organic matter content of the greenhouse soils was ascribed to environmental or management factors rather than the clay content of the soil.Accumulation of soluble nutrients,especially inorganic N,was due to over-application of fertilizers,which also caused soil acidification.The average amount of readily available N,P,and K accumulated in the greenhouse soils was estimated to be equal to or higher than the annual input of these nutrients as a fertilizer,indicating that a reduction in fertilizer application was possible and recommended.In contrast,a very low available Si content was observed in the paddy soils,suggesting the need for Si application for rice production.

  19. Relative paleointensity of the geomagnetic field during the past 0.8 Ma from Nihewan Basin, Hebei Province, China

    Institute of Scientific and Technical Information of China (English)

    WANG Yong; CHI Zhenqing; LEE Tehquei; MIN Longrui; CHU Huiyan

    2004-01-01

    We conducted a detailed rock magnetic study on upper 80 m of Jing'erwa core from the Nihewan basin. The results indicate that the sediments from Jing'erwa core are suitable for relative paleointensity study, and anhysteretic remanent magnetization (ARM) can be used as the normalization parameter of the natural remanent magnetization (NRM). Our relative paleointensity data of upper 80 m of Jing'erwa core provide a continuous record of the intensity variation during the last 0.8 Ma, which correlates well with the results from marine sediments cores in the Pacific Ocean. This means that the sediments records are reliable for relative paleointensity of Earth's magnetic field, and suggests that these sediments have recorded the real changes of geomagnetic field, which would provide a new method for regional stratigraphic correlation.

  20. 青海柴达木盆地南八仙油气田油源与成藏机理%Source of oils and mechanism of reservoir formation of the Nanbaxian oil and gas field, Qaidam Basin, Qinghai Province, China

    Institute of Scientific and Technical Information of China (English)

    苏爱国; 朱扬明; 梁狄刚; 韩德馨; 张水昌; 王延斌; 黄海平

    2003-01-01

    柴达木盆地南八仙油气田不同油气藏间原油性质特征变化明显,油层在纵向井段上分布范围逾 3 000余 m.通过地球化学实验并结合构造等地质条件分析,认为该区各种深、浅层油气藏中的原油具有煤成烃的基本地球化学特征,并且为同一来源,油源为临近地区较深部位中侏罗统煤系地层;该区深、浅层原油物性间的差异也反映在地球化学指标上,其成因或成藏机理是:深部早期油藏在断裂等地质作用下发生了明显的蒸发分馏作用,其分馏出的产物在浅部再次聚集成藏.

  1. Post-collisional magmatism: Consequences of UHPM terrane exhumation and orogen collapse, N. Qaidam UHPM belt, NW China

    Science.gov (United States)

    Wang, Mengjue; Song, Shuguang; Niu, Yaoling; Su, Li

    2014-12-01

    Exhumation of subducted slabs and extensional collapse of orogens are the main tectonic processes in ancient and modern continental collisional zones. Magmatism during these two processes may play important roles in understanding reworking and growth of the continental crust. We report here that a series of plutonic magmas, including intrusions of two-mica granite, tonalite, granodiorite, biotite monzogranite, porphyritic biotite granite and diorite, as well as contemporaneous mafic dykes, have been recognized in Dulan eclogite-bearing terrane, the North Qaidam ultra-high pressure metamorphic (UHPM) belt. The magmatism represented by these plutons is temporally ~ 20-30 million years (Mys) younger than the UHPM age, lasting for ~ 40 Mys and derived from different sources with different mechanisms. The magmatism was initiated by exhumation of UHPM terranes during which strongly-peraluminous two-mica granite and metaluminous tonalite were produced respectively by decompression melting of the exhumed UHPM upper and lower continental crust, respectively. The genesis of mafic magmatic enclave (MME)-hosting granodiorite with a clear hybrid signature and coeval biotite monzogranite reflected the upwelling of asthenospheric mantle by extension of lithosphere during the orogen collapse. It was induced by detachment of the subducted lithospheric mantle, which then brought heat and mantle material into continental crust and triggered the partial melting of the exhumed UHPM continental crust, and gave rise to mixing of crustal and mantle melts. Porphyritic biotite granite reflects a late melting event of continental crust. Diorite marked by high magnesium content represents mantle melts with slight crustal contamination, which implies that the orogen has been unrooted and collapsed completely. The post-collisional magmatism of the North Qaidam belt provides an improved understanding for the late thermal and tectonic evolution of a UHPM continental collision zone.

  2. Effect of Faulting on Ordovician Carbonate Buried-Hill Reservoir Beds in Hetianhe Gas Field,Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    Lü Xiuxiang; Bai Zhongkai; Li Jianjiao; Wang Weiguang; Fu Hui; Wang Qinghua

    2008-01-01

    Ordovician carbonate buried-hill reservoir beds in the Hetianhe (和田河) gas field,located in the Mazhatage (玛扎塔格) structural belt on the southern margin of the Bachu (巴楚) faulted uplift,southwestern Tarim basin,were studied.Based on field survey,core and slice observation,the general characteristics of carbonate buried-hill reservoir beds and specifically Ordovician carbonate buried-hill reservoir beds in the Hetianhe gas field were discussed.The karst zone of the reservoir beds in Hetianhe gas field was divided into superficial karst zone,vertical infiltration karst zone,lower subsurface flow karst zone,and deep sluggish flow zone from top to bottom.The effects of faulting on Ordovician carbonate buried-hill reservoir beds in the Hetianhe gas field were obvious.The faulting intensified the karstification and increased the depth of denudation.Faulting and subsequent fracture growth modified the reservoir beds and improved the physical property and quality of the reservoir beds.Moreover,faulting enhanced the development of the dissolution holes and fractures and increased the thickness of the effective reservoir beds.Meanwhile,faulting made the high porosity-permeability carbonate belts,which created conditions for the hydrocarbon accumulation,develop near the fault zone.

  3. Implications of Magmatic Events on Hydrocarbon Generation: Occurrences of Gabbroic Rocks in the Orito Field, Putumayo Basin, SW Colombia

    Science.gov (United States)

    Vásquez, M.; Altenberger, U.; Romer, R. L.

    2005-12-01

    Mafic dikes and sills intruded the sedimentary succession in the Orito Oil Field, located in the Putumayo Basin, SW Colombia. One sample from the Orito-4 well yields a Late Miocene to Pliocene age (40K/40Ar on amphibole 6.1 ± 0.7 Ma) for the igneous event in the basin. This coincides with the widely recognized regional Andean orogenic uplift that affected most of sub-Andean Peru, Ecuador, and Colombia. Furthermore, the uplift consequently coincides with a second pulse of hydrocarbon generation and expulsion in the Putumayo Basin. This second pulse was thermally more evolved than the first one (Late Oligocene - Miocene). The high content of CO2 in the gas budget recovered in different wells along the basin may be related to the heat flux of the mafic intrusions. There are four geological events that coincide with this large scale evolution during the late Miocene to early Pliocene (13 - 3 Ma): regional orogenic uplift, persistent igneous intrusions, CO2 formation, and a second pulse of hydrocarbon generation and expulsion. The Late Miocene - Pliocene age of the intrusion is the key to formulate a hypothesis where these four events are joined together. Regional uplift and intrusions: The mafic rocks of the Orito Oil Field show Sr-Nd-Pb isotopic compositions that suggest derivation from a mantle source below the western edge of the South American continent. The geochemical signature of these rocks that form part of the Northern Volcanic Zone (NVZ) reflects subduction-related magmatism. Thus, they record subduction and start of the last pervasive uplift episode that took place during the Late Neogene. Intrusions and second migration phase: The Late Miocene pulse of hydrocarbon generation and migration coincides closely with the estimated age of the intrusions; therefore, a causal link with the geothermal anomaly induced by the mafic igneous rocks is likely. The temperature of a mafic magma reaching 1000 to 1200°C is sufficient to heat the host rocks, where the

  4. Mercury isotopic composition of hydrothermal systems in the Yellowstone Plateau volcanic field and Guaymas Basin sea-floor rift

    Science.gov (United States)

    Sherman, L.S.; Blum, J.D.; Nordstrom, D.K.; McCleskey, R.B.; Barkay, T.; Vetriani, C.

    2009-01-01

    To characterize mercury (Hg) isotopes and isotopic fractionation in hydrothermal systems we analyzed fluid and precipitate samples from hot springs in the Yellowstone Plateau volcanic field and vent chimney samples from the Guaymas Basin sea-floor rift. These samples provide an initial indication of the variability in Hg isotopic composition among marine and continental hydrothermal systems that are controlled predominantly by mantle-derived magmas. Fluid samples from Ojo Caliente hot spring in Yellowstone range in δ202Hg from - 1.02‰ to 0.58‰ (± 0.11‰, 2SD) and solid precipitate samples from Guaymas Basin range in δ202Hg from - 0.37‰ to - 0.01‰ (± 0.14‰, 2SD). Fluid samples from Ojo Caliente display mass-dependent fractionation (MDF) of Hg from the vent (δ202Hg = 0.10‰ ± 0.11‰, 2SD) to the end of the outflow channel (&delta202Hg = 0.58‰ ± 0.11‰, 2SD) in conjunction with a decrease in Hg concentration from 46.6pg/g to 20.0pg/g. Although a small amount of Hg is lost from the fluids due to co-precipitation with siliceous sinter, we infer that the majority of the observed MDF and Hg loss from waters in Ojo Caliente is due to volatilization of Hg0(aq) to Hg0(g) and the preferential loss of Hg with a lower δ202Hg value to the atmosphere. A small amount of mass-independent fractionation (MIF) was observed in all samples from Ojo Caliente (Δ199Hg = 0.13‰ ±1 0.06‰, 2SD) but no significant MIF was measured in the sea-floor rift samples from Guaymas Basin. This study demonstrates that several different hydrothermal processes fractionate Hg isotopes and that Hg isotopes may be used to better understand these processes.

  5. Estimation of VOC emissions from produced-water treatment ponds in Uintah Basin oil and gas field using modeling techniques

    Science.gov (United States)

    Tran, H.; Mansfield, M. L.; Lyman, S. N.; O'Neil, T.; Jones, C. P.

    2015-12-01

    Emissions from produced-water treatment ponds are poorly characterized sources in oil and gas emission inventories that play a critical role in studying elevated winter ozone events in the Uintah Basin, Utah, U.S. Information gaps include un-quantified amounts and compositions of gases emitted from these facilities. The emitted gases are often known as volatile organic compounds (VOCs) which, beside nitrogen oxides (NOX), are major precursors for ozone formation in the near-surface layer. Field measurement campaigns using the flux-chamber technique have been performed to measure VOC emissions from a limited number of produced water ponds in the Uintah Basin of eastern Utah. Although the flux chamber provides accurate measurements at the point of sampling, it covers just a limited area of the ponds and is prone to altering environmental conditions (e.g., temperature, pressure). This fact raises the need to validate flux chamber measurements. In this study, we apply an inverse-dispersion modeling technique with evacuated canister sampling to validate the flux-chamber measurements. This modeling technique applies an initial and arbitrary emission rate to estimate pollutant concentrations at pre-defined receptors, and adjusts the emission rate until the estimated pollutant concentrations approximates measured concentrations at the receptors. The derived emission rates are then compared with flux-chamber measurements and differences are analyzed. Additionally, we investigate the applicability of the WATER9 wastewater emission model for the estimation of VOC emissions from produced-water ponds in the Uintah Basin. WATER9 estimates the emission of each gas based on properties of the gas, its concentration in the waste water, and the characteristics of the influent and treatment units. Results of VOC emission estimations using inverse-dispersion and WATER9 modeling techniques will be reported.

  6. Using geochemical tracing system to identify new types of gas sources in marine strata of the Hotan River Gas Field in the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    There are natural gas sources of various modes of occurrence in superimposed basins. Besides the conventional kerogen and ancient oil reservoir, dispersed soluble organic matter (DSOM) is an important direct gas source. Because of its wide distribution, great potential to generate gas and proneness to crack under catalysis, DSOM is an important type of gas source in the highly evolved zones in marine strata. Through the geological and geochemical analysis that reflects the long-period evolvement and multiple gas accumulation processes in marine strata, and using the ternary geochemical tracing system, here we study the origin and accumulation of the natural gas in the Hotan River Gas Field in the Tarim Basin. The natural gas is produced from highly evolved and cracked DSOM in the Hotan River Gas Field, and it is accumulated after migrating for a long distance along faults. This conclusion is of great significance to the further expansion of the oil and gas exploration fields in the Tarim Basin.

  7. High-resolution Topography of PACMANUS and DESMOS Hydrothermal Fields in the Manus Basin through ROV "FAXIAN"

    Science.gov (United States)

    Luan, Z.; Ma, X.; Yan, J.; Zhang, X.; Zheng, C.; Sun, D.

    2016-12-01

    High-resolution topography can help us deeply understand the seabed and related geological processes (e.g. hydrothermal/cold spring systems) in the deep sea areas. However, such studies are rare in China due to the limit of deep-sea detection technology. Here, we report the advances of the application of ROV in China and the newly measured high-resolution topographical data in PACMANUS and DESMOS hydrothermal fields. In June 2015, the ROV "FAXIAN" with a multibeam system (Kongsberg EM2040) was deployed to measure the topography of PACMANUS and DESMOS hydrothermal fields in the Manus basin. A composite positioning system on the ROV provided long baseline (LBL) navigation and positioning during measurements, giving a high positioning accuracy (better than 0.5m). The raw bathymetric data obtained were processed using CARIS HIPS (version 8.1). Based on the high-resolution data, we can describe the topographical details of the PACMANUS and DESMOS hydrothermal fields. High-resolution terrain clearly shows the detailed characters of the topography in the PACMANUS hydrothermal field, and some cones are corresponding to the pre discovered hydrothermal points and volcanic area. Most hydrothermal points in the PACMANUS hydrothermal field mainly developed on the steep slopes with a gradient exceeding 30 °. In contrast, the DESMOS field is a caldera that is approximately 250 m deep in the center with an E-W diameter of approximately1 km and a N-S diameter of approximately 2 km. The seafloor is much steeper on the inner side of the circular fracture. Two highlands occur in the northern and the southern flanks of the caldera. Video record indicated that pillow lava, sulfide talus, breccia, anhydrite, outcrops, and sediment all appeared in the DESMOS field. This is the first time for the ROV "FAXIAN" to be used in near-bottom topography measurements in the hydrothermal fields, opening a window of deep-sea researches in China.

  8. Process and mechanism for oil and gas accumulation, adjustment and reconstruction in Puguang Gas Field, Northeast Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    With the discoveries of a series of large gas fields in the northeast of Sichuan Basin, such as Puguang and Longgang gas fields, the formation mechanism of the gas reservoir containing high H2S in the ancient marine carbonate formation in superposition-basin becomes a hot topic in the field of petroleum geology. Based on the structure inversion, numerical simulation, and geochemical research, we show at least two intervals of fluid transfer in Puguang paleo-oil reservoir, one in the forepart of late Indo-Chinese epoch to early Yanshan epoch and the other in the metaphase of early Yanshan epoch. Oil and gas accumulation occurred at Puguang structure through Puguang-Dongyuezhai faults and dolomite beds in reef and shoal facies in Changxing Formation (P2ch) - Feixianguan Formation (T1f) in the northwest and southwest directions along three main migration pathways, to form Puguang paleo-oil reservoir. Since crude oil is pyrolysised in the early stage of middle Yanshan epoch, Puguang gas reservoir has experienced fluid adjusting process controlled by tectonic movement and geochemical reconstruction process controlled by thermochemical sulfate reduction (TSR). Middle Yan-shan epoch is the main period during which the Puguang gas reservoir experienced the geochemical reaction of TSR. On one hand, TSR can recreate the fluid in gas reservoir, which makes the gas drying index larger and carbon isotope heavier. On the other hand, the reciprocity between fluid regarding TSR (hydrocarbon, H2S, and water) and reservoir rock induces erosion of the reservoir rocks and anhydrite alteration, which improves reservoir petrophysical properties. Superimposed by later tectonic movement, the fluid in Puguang reservoir has twice experienced adjustment, one in the late Yanshan epoch to the early Himalayan epoch and the other time in late Himalayan epoch, after which Puguang gas reservoir is finally developed.

  9. Crustal structure and rift tectonics across the Cauvery–Palar basin, Eastern Continental Margin of India based on seismic and potential field modelling

    Indian Academy of Sciences (India)

    D Twinkle; G Srinivasa Rao; M Radhakrishna; K S R Murthy

    2016-03-01

    The Cauvery–Palar basin is a major peri-cratonic rift basin located along the Eastern Continental Margin of India (ECMI) that had formed during the rift-drift events associated with the breakup of eastern Gondwanaland (mainly India–Sri Lanka–East Antarctica). In the present study, we carry out an integrated analysis of the potential field data across the basin to understand the crustal structure and the associated rift tectonics. The composite-magnetic anomaly map of the basin clearly shows the onshore-tooffshore structural continuity, and presence of several high-low trends related to either intrusive rocks or the faults. The Curie depth estimated from the spectral analysis of offshore magnetic anomaly data gave rise to 23 km in the offshore Cauvery–Palar basin. The 2D gravity and magnetic crustal models indicate several crustal blocks separated by major structures or faults, and the rift-related volcanic intrusiverocks that characterize the basin. The crustal models further reveal that the crust below southeast Indian shield margin is ∼36 km thick and thins down to as much as 13–16 km in the Ocean Continent Transition (OCT) region and increases to around 19–21 km towards deep oceanic areas of the basin. Thefaulted Moho geometry with maximum stretching in the Cauvery basin indicates shearing or low angle rifting at the time of breakup between India–Sri Lanka and the East Antarctica. However, the additional stretching observed in the Cauvery basin region could be ascribed to the subsequent rifting of Sri Lanka from India. The abnormal thinning of crust at the OCT is interpreted as the probable zone of emplaced Proto-Oceanic Crust (POC) rocks during the breakup. The derived crustal structure along with other geophysical data further reiterates sheared nature of the southern part of the ECMI.

  10. Organic geochemistry of oils and condensates in the Kekeya field, southwest depression of the Tarim Basin (China)

    Energy Technology Data Exchange (ETDEWEB)

    Maowen Li; Snowdon, L.R. [Geological Survey of Canada, Calgary (Canada); Renzi Lin; Peirong Wang [Jianghan Petroleum Institute, Hubei (China); Yongsheng Liao; Peilong Li [Shengli Petroleum Administrative Bureau, Shandong (China)

    1999-07-01

    This study shows that the oils and condensates in the Kekeya Field in the Tarim Basin, NW China, belong to a single family, most likely derived from marine shale source rocks deposited under oxic-suboxic conditions with mixed terrigenous and algal-bacterial organic inputs. The maturity data clearly indicate that the paraffinic condensates were not formed by thermal cracking of oil during late catagenesis (R{sub o} > 1.2%). Both the oils and condensates were generated within the normal oil window, whereas addition of gaseous hydrocarbons from a separate source resulted in migration fractionation and hence spuriously high heptane indices. Age specific biomarkers show that the oils and condensates were not generated from the Mesozoic-Cenozoic strata, but from the Carboniferous-Permian sections. 1D basin modelling results are consistent with this interpretation, suggesting that the Mesozoic-Eocene strata are currently immature with respect to hydrocarbon generation and expulsion. Deep-seated faults may have provided routes for upward fluid migration at the time of active deformation during several pulses of the Himalayan orogeny. The favoured targets for further petroleum exploration in front of the Kunlun Mountains include the deep structures within the Carboniferous-Permian strata for indigenous petroleum accumulations and anticlines and stratigraphic traps within the Mesozoic-Cenozoic sections that are cut by deep-seated thrust faults where secondary petroleum accumulations most likely occurred. (author)

  11. Genetic features of gas-condensate reservoirs in the Kekeya Field,southwest depression in the Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Oils,condensates and natural gases in the Kekeya Field,southeast depression of the Tarim Basin were studied for their geochemical characteristics. According to the distribution analysis of the C2/C3 values with C1/C2 values,C2/C3 values with C1/C3 values,as well as C2/C3 values with dryness index,there are two different types of natural gases in the studied field,which are spatially regularly distributed. One is the oil cracking gas,located on shallow reservoirs over X52 reservoir,namely Upper oil legs;the other is kerogen cracking gas,located on X72 reservoirs,X8 reservoirs and E2k reservoirs,namely Lower oil legs. In addition,the distribution patterns of molar concentration of oils and condensates with different carbon numbers of the n-alkanes in the Kekeya Field indicate that the crude oils have experienced several kinds of secondary alterations,which were closely related to the charging of gaseous hydrocarbons after petroleum accumulation. These results indicate that,based on the research of δ13C values of individual hydrocarbons,heptane values and isoheptane values of light hydrocarbons and aromatic maturity parameters for oils,condensates and natural gases,oils and gases were charged at different geological time in the Kekeya Field.

  12. Formation of Fe-Si-Mn oxyhydroxides at the PACMANUS hydrothermal field, Eastern Manus Basin: Mineralogical and geochemical evidence

    Science.gov (United States)

    Zeng, Zhigang; Ouyang, Hegen; Yin, Xuebo; Chen, Shuai; Wang, Xiaoyuan; Wu, Li

    2012-10-01

    Samples of Fe-Si-Mn oxyhydroxides were collected from the PACMANUS hydrothermal field, which lies in a young back-arc setting in the Eastern Manus Basin. The purpose of the study was to understand the origin and characteristics of Fe-Si-Mn oxyhydroxides associated with massive sulfides in a back-arc basin. The PACMANUS Fe-Si-Mn oxyhydroxides are composed of Fe oxyhydroxides and Mn oxyhydroxides with opal-A and nontronite; they have very low concentrations of trace elements (except for Ba, Mo, V and U) and rare earth elements, and they show REE distribution patterns with positive Eu anomalies and slight enrichments of LREEs. The Fe-Si-Mn oxyhydroxides appear to be precipitated mainly from hydrothermal fluid with limited seawater contamination, and scavenged trace metals are predominantly from the ambient seawater. The differences in the REE distribution patterns between the Fe-oxyhydroxide fraction and Mn-oxyhydroxide fraction originate from diagenetic processes. There are diverse filamentous microtextures resembling unique microbial populations, suggesting microbially-mediated mineralization during the precipitation of the Fe-Si-Mn oxyhydroxides. A possible genetic scenario for the formation of Fe-Si-Mn oxyhydroxides in the PACMANUS hydrothermal field is proposed: (1) precipitation of silica by the mixing of hydrothermal fluid with seawater at a diffuse vent, promoted by Fe-oxidizing bacteria and microbial mineralization; (2) rapid precipitation of Fe-oxyhydroxide from the hydrothermal fluid due to Fe2+ oxidation; (3) growth of Mn-oxyhydroxide partially encasing Fe-oxyhydroxide. Microbes act through the whole scenario. The Fe-Si-Mn oxyhydroxides have undergone changes as a consequence of fluctuating hydrothermal conditions and subsequent diagenetic degradation.

  13. Can We Trust Our Finds Distribution Maps? : Anchoring Field Survey Data by Field Experiments in the Raganello Basin (Calabria, Italy)

    NARCIS (Netherlands)

    van Leusen, Martijn; Witmer, Evelien

    2014-01-01

    Archaeological field surveys, especially of the ‚non-site’ or ‚off-site’ kind, aim to produce a detailed, fair and complete record of the archaeological remains detectable on the land surface. However, all practicing survey archaeologists agree that many factors conspire to reduce the representativi

  14. Field protocol and GIS analysis of connectivity in semiarid headwaters: metrics and evidences from Carcavo Basin (SE Spain)

    Science.gov (United States)

    Marchamalo, Miguel; Hooke, Janet; Gonzalez-Rodrigo, Beatriz; Sandercock, Peter

    2017-04-01

    Soil erosion and land degradation are severe problems in headwaters of ephemeral streams in semiarid Mediterranean regions, particularly in marginal upland areas over erodible parent material. Field-based information is required about the main pathways of sediment movement, the identification of sources and sinks and the influence of relevant factors. The EU-funded project RECONDES approached this reality by monitoring connectivity pathways of water and sediment movement in the landscape with the aim of identifying hotspots that could then be strategically targeted to reduce soil erosion and off-site effects. A protocol including field work and GIS analysis was developed and applied to a set of microcatchments in Carcavo Basin (Spain). The philosophy of the protocol was based on the repeated mapping after rainfall events so that frequency of activity of pathways could be evaluated. Connectivity was evaluated for each site and event using specific metrics: maximum mapped connectivity (corresponding to the largest recorded event), density of connected pathway links (m/ha) and frequency of activity (times active/total). Repeated connectivity mapping allowed identifying hotspots of erosion. The effect of structural and functional factors on connectivity was investigated. Field data is also valuable for validating future connectivity models in semiarid landscapes under highly variable and unpredictable conditions.

  15. Field Review of Fish Habitat Improvement Projects in the Grande Ronde and John Day River Basins of Eastern Oregon.

    Energy Technology Data Exchange (ETDEWEB)

    Beschta, Robert L.; Platts, William S.; Kauffman, J. Boone

    1991-10-01

    The restoration of vegetation adapted to riparian environments and the natural succession of riparian plant communities is necessary to recreate sustainable salmonid habitat and should be the focal point for fish habitat improvement programs. In mid-August of 1991, a field review of 16 Salmon habitat improvement sites in the Grande Ronde and John Day River Basins in Eastern Oregon was undertaken. The review team visited various types of fish habitat improvements associated with a wide range of reach types, geology, channel gradients, stream sizes, and vegetation communities. Enhancement objectives, limiting factors, landuse history, and other factors were discussed at each site. This information, in conjunction with the reviewer's field inspection of portions of a particular habitat improvement project, provided the basis for the following report. This report that follows is divided into four sections: (1) Recommendations, (2) Objectives, (3) Discussion and Conclusions, and (4) Site Comments. The first section represents a synthesis of major recommendations that were developed during this review. The remaining sections provide more detailed information and comments related to specific aspects of the field review.

  16. Geology reinterpretation of an inactive old field-Mata 3, Venezuelan East Basin-using computer methods

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, O.; Rivero, C.; Abud, J. [East Univ., Corpoven, S.A. (Venezuela)

    1996-08-01

    Nowadays to find a new oil field is a very dificult task that the petroleum people know very well; therefore the reactivation of an old oil field that had important production is the best way to increase the economic benefits for the Corporation and for the country in general. In this paper, the most important point was the Geology Study regarding the reopening of the Mata-3 oil field, which ceased to be active 15 years ago, after producing 30 mmbls of light oil. There are 30 prospective sands but only 3 of them have produced 70% of the primary production. Thus, the principal objectives were the S2, S3, 4 sands of Oficina Formation (Venezuelan East Basin) in 476 wells located in this area. The following computer systems that were available to us: GIPSIE System, Vax (Intergraph Co.); PMSE System, Vax (Intergraph Co.); CPS-3 System, Unix (Radian Co.); and SIGEMAP System PC (Corpoven, S.A.). All of them assist in the different tasks that must be done by the geologists working in the interpretation area. In the end, we recommended 40 wells to workover (2 wells/year for 20 years) and thereby to increase the POI (petroleum in situ) and increase the reserves by 13.4 mmbls of fight oil, important commercial production. The estimate of the total investment is about $2 million (340 mmBs.).

  17. The development study on gas recycling injection in Yaha Gas Condensate Field, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    孙龙德; 宋文杰; 江同文

    2003-01-01

    The Yaha Gas Condensate Field is the largest one discovered in China so far. In order to enhance the condensate recovery, gas recycling at 50 MPa has been implemented in Yaha field. Such high-pressure injection is very rare throughout the world. This paper offers the description of the geology and fluid phase behavior of Yaha field. The reservoir productivity and injectivity equations, the optimal development and well patterns are presented. The follow-up investigation of the design implementation leads to the reasonable adjustment of the original development plan. The perforation principle and program of gas recycling for Yaha field are set up. The numerical simulation is used to predict the future production performance of gas recycling. Finally, a complete set of high-pressure gas recycling technology suite has been established. The field has come on-stream for one and a half year with condensate throughput of 590000 t in 2001, and fat profit returned. The success of high-pressure gas recycling in the Yaha field is of considerable importance from the theoretical and practical points of view and will considerably benefit the future development of other gas condensate fields in China.

  18. Local cline of the forest vegetation in zones of the Western Donets Basin coal-fields

    Directory of Open Access Journals (Sweden)

    O. S. Fesenko

    2005-12-01

    Full Text Available The forest herbaceous vegetation communities in the zone of mine fields have been investigated. A seral dynamics of phytocenosis is characterised on the basis of bioindication of changes in the plant associations’ structure on disturbed lands.

  19. High temperature annealing of fission tracks in fluorapatite, Santa Fe Springs oil field, Los Angeles Basin, California

    Science.gov (United States)

    Naeser, Nancy D.; Crowley, Kevin D.; McCulloh, Thane H.; Reaves, Chris M.; ,

    1990-01-01

    Annealing of fission tracks is a kinetic process dependent primarily on temperature and to a laser extent on time. Several kinetic models of apatite annealing have been proposed. The predictive capabilities of these models for long-term geologic annealing have been limited to qualitative or semiquantitative at best, because of uncertainties associated with (1) the extrapolation of laboratory observations to geologic conditions, (2) the thermal histories of field samples, and (3) to some extent, the effect of apatite composition on reported annealing temperatures. Thermal history in the Santa Fe Springs oil field, Los Angeles Basin, California, is constrained by an exceptionally well known burial history and present-day temperature gradient. Sediment burial histories are continuous and tightly constrained from about 9 Ma to present, with an important tie at 3.4 Ma. No surface erosion and virtually no uplift were recorded during or since deposition of these sediments, so the burial history is simple and uniquely defined. Temperature gradient (???40??C km-1) is well established from oil-field operations. Fission-track data from the Santa Fe Springs area should thus provide one critical field test of kinetic annealing models for apatite. Fission-track analysis has been performed on apatites from sandstones of Pliocene to Miocene age from a deep drill hole at Santa Fe Springs. Apatite composition, determined by electron microprobe, is fluorapatite [average composition (F1.78Cl0.01OH0.21)] with very low chlorine content [less than Durango apatite; sample means range from 0.0 to 0.04 Cl atoms, calculated on the basis of 26(O, F, Cl, OH)], suggesting that the apatite is not unusually resistant to annealing. Fission tracks are preserved in these apatites at exceptionally high present-day temperatures. Track loss is not complete until temperatures reach the extreme of 167-178??C (at 3795-4090 m depth). The temperature-time annealing relationships indicated by the new data

  20. Geothermal Regime, Thermal History and Hydrocarbon Generation Types of Sedimentary Basins in the Continental Area of China

    Institute of Scientific and Technical Information of China (English)

    QiuNansheng; JamesPuckette; JinZhijun; WangJiyang

    2005-01-01

    The thermal regimes in sedimentary basins in the continental area of China are varied and reflect differences in geological settings. As a result of these variable thermal regimes, the history of hydrocarbon generation in each basin is also different. An east-west profile of the thermal threshold across the continental basins of China, like the Liaohe Basin, the North China Basin, the Ordos Basin, the Qaidam Basin and the Tarim Basin, was constructed using large numbers of heat flow measurements, temperature data and rock thermophysical parameters. Isotherms, surface heat flow, mantle heat flow and Moho temperature beneath the basins are shown in the profile, which illustrates changes in some thermal characteristics between basins in east China and those in west China. Thermal evolution histories in basins were reconstructed using Easy%Ro method, apatite fission track annealing and other paleothermometers. Typical hydrocarbon generation histories of the primary source rocks were modeled by referring to the thermal evolution data. Thermal stages controlled source rocks maturation and oil and gas generation, and influenced the type of hydrocarbon (oil and gas) production in the basins.

  1. Hydrology of the Price River basin, Utah, with emphasis on selected coal-field areas

    Science.gov (United States)

    Waddell, Kidd M.; Dodge, J.E.; Darby, D.W.; Theobald, S.M.

    1986-01-01

    Data obtained during a hydrologic study of the Price River basin, Utah, are used to describe seasonal variations of flow of springs, relation between ground water and surface water, hydraulic properties of the ground-water reservoir, ground-water recharge and discharge, flood characteristics of streams, mineralogic composition and depositional rates of sediments, nutrient and inorganic loading in streams and Scofield Reservoir, and water budgets for selected basins. Additional study and monitoring are needed to detect possible hydrologic changes caused by coal mining. Much of the ground-water discharge from the Star Point Sandstone in the Mesaverde Group in the Wasatch Plateau occurs along faults. In the Book Cliffs, where faulting is less extensive, most of the ground-water discharge is from the Flagstaff Limestone. The Flagstaff Limestone is greatly diffusive, has a small storage coefficient, and contains water which is perched. Springs issuing from the Star Point Sandstone in the Mud Creek drainage (Wasatch Plateau) had recession indexes greater than 365 days per log cycle. Springs issuing at higher altitudes from the Colton Formation and the Flagstaff Limestone in the Soldier Creek area (Book Cliffs) have great seasonal variability, with recession indexes ranging from 24 to 115 days per log cycle. Estimated transmissivities in the Soldier Creek area ranged from 0.003 foot squared per day in the lower part of the Castlegate Sandstone to 0.07 foot squared per day in the Price River Formation. Seepage from the Star Point Sandstone is the major contributor to base flow of the stream in Eccles Canyon (Wasatch Plateau). Gains of as much as 230 gallons per minute occurred near a fault zone which crosses Eccles Canyon at the junction with South Fork Canyon. The potentiometric surface of water in the Blackhawk Formation in the Wasatch Plateau (Mud Creek drainage) and the Book Cliffs (Soldier Creek area) generally is above the coal zones, and dewatering will be necessary

  2. Seismic and well logging interpretation for evaluation of the lower Bahariya reservoir, southwest Qarun (SWQ) Field, Gindi Basin, Egypt

    Science.gov (United States)

    Sarhan, Mohammad Abdelfattah; Basal, A. M. K.; Ibrahim, Ibrahim Mohamed

    2017-09-01

    This paper focuses on seismic and well log interpretations for evaluating the sandstones of the Cenomanian Bahariya Formation in the southwest Qarun Field, Gindi Basin, northern Western Desert of Egypt. The seismic profiles display a clear anticlinal structure intersected by reverse faults in the study area. This faulted anticline has been interpreted to be one of the Syrian arc system folds formed by Upper Cretaceous tectonic inversion, which resulted from the NW movement of the African Plate relative to Laurasia. This anticline has been recommended as a target for exploration by the present work as it may represent a structural trap for hydrocarbon accumulation. The sandstones of the Lower Bahariya Formation in the southwest Qarun Field display good reservoir characteristics. The interpretation of the available well log data for the SWQ-21 and SWQ-25 wells for the Lower Bahariya Formation reflects a good reservoir quality for oil production in its topmost part. This reservoir possesses low SW (<50%), high porosity (16%), low SW/SXO and low BVW (<0.09) which all reflect a high potential for oil production.

  3. AVO analysis and modeling applied to fracture detection in coalbed methane reservoirs, Cedar Hill Field, San Juan basin, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, A.C.B. [Petrobras, Rio de Janeiro (Brazil); Davis, T.L.; Anderson, J.E.; Benson, R.D. [Colorado School of Mines, Golden, CO (United States)

    1994-12-31

    The Cedar Hill Field in the San Juan Basin, New Mexico, produces methane from fractured coalbed of the Fruitland Formation. The presence of fracturing is critical to methane production due to the absence of matrix permeability in the coals. To help characterize this coalbed reservoir a three-dimensional, multicomponent seismic survey was acquired in this field. Prestack P-wave amplitude data are used to delineate zones of larger Poisson`s ratio contrasts (or higher crack densities) in coalbed methane reservoir, while source-receiver azimuth sorting is used to detect preferential directions of azimuthal anisotropy. Two modeling techniques (using ray tracing and reflectivity methods) predict the effects of fractured coal-seam zones on non-normal P-wave reflectivity. Synthetic CMP gathers are generated for a horizontally layered earth model, which uses elastic parameters derived from sonic and density log measurements. Fracture density variations in the coalbeds are simulated by anisotropic modeling. The large acoustic impedance contrasts associated with the sandstone/coal interfaces dominate the P-wave reflectivity response. They far outweigh the effects of contrasts in anisotropy parameters, for the computed models. Seismic AVO analysis of nine macrobins obtained from the 3-D volume confirms model predictions. Areas with large AVO productions identify coal zones with large Poisson`s ratio contrast, therefore high fracture density.

  4. Diagenesis and porosity evolution of sandstone reservoirs in the East Ⅱ part of Sulige gas field, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    Yang Renchao; Fan Aiping; Han Zuozhen; Wang Xiuping

    2012-01-01

    It is becoming an important controlling factor of gas exploration and exploitation in the east part of Sulige gas field in the Ordos Basin where the reservoir of main gas formations is tight sandstones.Employing experimental methods of slice identification,casting slice,scan electron microscope,and X-ray diffractions,we studied the characteristics of petrology and diagenesis on reservoirs in Shan1 section of Shanxi formation and He8 section of Shihezi formation of the Permian system in the East Ⅱ part of Sulige gas field.The results include:(1) the main sandstones in these areas are dominated by lithic sandstone and lithic silicarenite with low grade of maturity; (2) the diagenesis of sandstone in these areas mainly include compaction,cementation,corrosion and alteration.Conclusions are as follows:(1) the diagenetic stage reached period B of the middle diagenetic stage; (2) the early diagenetic compaction is one of the main factors to decreasing porosity:(3) the secondary pores formed by corrosion in acidity medium conditions in period A of the middle diagenetic stage can distinctly ameliorate the poor reservoir capability of sandstone and; (4) cementation in period B of the middle diagenetic stage is the most important factor leading to poor physical property of sandstone reservoirs.

  5. Tectonic stress field and its effect on hydrocarbon migration and accumulation in Mesozoic and Cenozoic in Kuqa depression, Tarim basin

    Institute of Scientific and Technical Information of China (English)

    ZENG; Lianbo; TAN; Chengxuan; ZHANG; Mingli

    2004-01-01

    Through rock acoustic emission experiments and structural deformation analysis, the tectonic stages in Meso-Cenozoic in the Kuqa depression of the Tarim basin are firstly divided. Then, combining with rock magnetic fabric analysis and memory information, the distribution characteristics of tectonic stress field of every tectonic stage are quantificationally resumed. At the same time, according to the distribution relation of tectonic stress field of hydrocarbon formation stage by the finite element numerical simulation method and the known hydrocarbon reservoirs, the effects of tectonic stress field on hydrocarbon migration and accumulation are further analyzed. The Kuqa depression has mainly experienced six tectonic movements since Mesozoic. Except that the tectonic stress field of the Early Yanshan stage (208-135 Ma) showed northeast-southwest extensional stress field where the orientation of the maximum principal compressive stress (σ1) was northwest-southeast, the others were compressive stress field where the orientations of the maximum principal compressive stress (σ1) were near north-south. Along with the closure of the paleo-Tethys ocean, the Kuqa depression in the Indosinian stage (250-208 Ma) was in strong compressive circumstance with apparently big maximum principal stress (σ1) magnitude. Due to the equilibrium adjustment of interior Eurasia, the Kuqa depression in the Early Yanshan stage (208-135 Ma) was in weak extensional circumstance with apparently small maximum principal stress (σ1) magnitude. From the Late Yanshan stage (135-65 Ma) on, with a series of collision events occurring at the south edge of Eurasia, the Kuqa depression was in compressive circumstance again in which the maximum principal stress (σ1) magnitude was from small to big in turn. The Late Himalayan stage (2.6-0.7 Ma) was the main tectonic deformation stage with the biggest principal compressive stress (σ1) magnitude. Tectonic stress field plays a dominant role in

  6. Provenance and sediment dispersal of the Triassic Yanchang Formation, southwest Ordos Basin, China, and its implications

    Science.gov (United States)

    Xie, Xiangyang

    2016-04-01

    The Ordos Basin in north central China records a transition from marine to non-marine deposition during the late Paleozoic to early Mesozoic. As a result, the northern and southern regions of the Ordos Basin show different tectonic histories and very distinctive sedimentation styles. Two deformation belts, the Qinling orogenic belt to the south and the Liupanshan thrust and fold belt to the west, controlled the structural evolution of the southern Ordos Basin during the early Mesozoic. Paleocurrent analysis, net-sand ratio maps, sandstone modal analysis, and U-Pb detrital zircon geochronology were used to document sediment sources and dispersal patterns of the Triassic Yanchang Formation in the southwest Ordos Basin. Paleocurrent measurements suggest that the sediments were mainly derived from the Liupanshan and the Qinling orogenic belts. Net-sand ratio maps show that several fan delta systems controlled sediment delivery in the south Ordos Basin. Both sandstone modal analysis and U-Pb detrital zircon geochronology suggest that the Yanchang Formation is locally sourced from both of the basin marginal deformation belts; the lower and middle sections are recycled Paleozoic sedimentary rocks mainly derived from the north Qinling orogenic belt, whereas for the upper section, the Qilian-Qaidam terranes and possibly the west Qinling orogenic belt began to shed sediments into the southwest Ordos Basin. Results have important implications for basin marginal tectonics and its controls on sedimentation of intracratonic basins in China and similar settings.

  7. Hydrogeochemistry of the formation waters in the San Francisco field, UMV basin, Colombia - A multivariate statistical approach

    Science.gov (United States)

    Cortes, J. E.; Muñoz, L. F.; Gonzalez, C. A.; Niño, J. E.; Polo, A.; Suspes, A.; Siachoque, S. C.; Hernández, A.; Trujillo, H.

    2016-08-01

    A wide variety of hydrogeochemical data were obtained through the analysis of the formation water samples collected from 118 producing wells from the San Francisco Oilfield (SFO) in the Upper Magdalena Valley (UMV) basin, Huila, Colombia. The study area is composed of deposited sandstone in fluvial-lacustrine marine environment, which characterized the formation waters as chloride-sodium water type. The brackish-saline facies identified can be attributed to evaporation, halite and dolomite dissolution along with water recharge of meteoric waters somewhere in the basin, probably from Magdalena River, the contribution of the SFO injection water system and significantly by the rock-water interaction. Some ionic ratios were used to confirm clearly that water-rock interactions play a significant role in the evolution of the hydrogeochemistry process in the SFO. The charge balance error ranges between -5.88% and 2.62% indicating very well balanced and mature water for blocks 1, 2 and 3 (north part of the field), and partially equilibrated and immature waters for blocks 4, 5, 6, 7, and 8 as is confirmed by Piper, Giggenbach, and Schöeller diagrams. Calculated scale and stability indices (Langelier, Ryznar, and Puckorius), besides halite and dolomite indexes, indicate that these formation waters are slightly saturated with respect to the calcite and dolomite and have strong tendency to the scale formation as well. Concentration maps were used to identify the geological factors that could have influenced its chemical composition and the hydrogeochemical processes involved in the field, such as halite dissolution, calcite or dolomite precipitation and cationic exchange reactions. The mineralogical distribution leads to the conclusion that the halite dissolution is mostly distributed in the Northeastern area of the SFO between B1, B3, B4, B5, and B6 blocks, the dolomite and calcite have greater concentrations between B5 and B6 blocks. The dissolved minerals followed the

  8. Geological emission of methane from the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    TANG Junhong; BAO Zhengyu; XIANG Wu; GOU Qinghong

    2008-01-01

    A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2·h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2·h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2·h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2·d), with a standard deviation of 0.43 mg/(m2·d), using the average methane flux of every hour in a day for all chambers. δ13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs.

  9. The characteristics of gravity and magnetic fields and the distribution of tight sandstone gas in the eastern Ordos Basin, China

    Science.gov (United States)

    Yuan, Bingqiang; Zhang, Huaan; Zhang, Chunguan; Xu, Haihong; Yan, Yunkui

    2016-04-01

    In order to perform gas exploration and determine the distribution pattern of gas in the Yanchang Oil Field in the eastern part of the North Shaanxi Slope, Ordos Basin, China, gravity and magnetic survey data were systemically collated, processed and interpreted in combination with the drilling data and recent seismic data. The genesis of gravity and magnetic anomalies and the relationship between the characteristics of the gravity and magnetic fields and known gas distribution were explored in order to predict the favourable exploration targets for gas. Gravity anomalies resulted both from the lateral variation in density of the basement rock and lateral lithologic transformation in the sedimentary cover. The regional magnetic anomalies were mainly caused by the basement metamorphic rocks and the residual magnetic anomalies may reflect the amount and general location of the volcanic materials in the overlying strata. The residual gravity and magnetic anomalies generated by high-density sandstone and high content of volcanics in the gas reservoir of the upper Paleozoic distorted and deformed the anomaly curves when they were stacked onto the primary background anomaly. The gas wells were generally found to be located in the anomaly gradient zones, or the distorted part of contour lines, and the flanks of high and low anomalies, or the transitional zones between anomaly highs and lows. The characteristics of gravity and magnetic fields provide significant information that can be used for guidance when exploring the distribution of gas. Based on these characteristics, five favourable areas for gas exploration were identified; these are quasi-equally spaced like a strip extending from the southeast to the northwest.

  10. Preliminary organic geochemical study of lignite from the Smederevsko Pomoravlje field (Kostolac basin, Serbia: Reconstruction of geological evolution and potential for rational utilization

    Directory of Open Access Journals (Sweden)

    Đoković Nataša

    2015-01-01

    Full Text Available The paper is aimed to determine the origin and geological evolution of lignites from Smederevsko Pomoravlje field (Kostolac Basin, Serbia. Possible rational utilization of coal is also considered. For this purpose numerous organic geochemical analyses have been applied to representative lignite samples. Obtained results showed that coal from the Smederevsko Pomoravlje field is typical humic coal. Peat-forming vegetation is dominated by gymnosperm plants. Coal forming plants belonged to the gymnosperm families Taxodiaceae, Cupressaceae, Phyllocladaceae and Pinaceae. Other precursors of organic matter (OM were microbial biomass, ferns and angiosperms. It is established that peatification was performed in neutral to slightly acidic, fresh water environment under anoxic to suboxic redox conditions. Maturity of OM is low in the phase of intense diagenetic processes. Biomarker compositions and values of corresponding parameters revealed that Smederevsko Pomoravlje field, Drmno field (Kostolac Basin and “A“ field (Kovin deposit represent a part of the unique lignite basin. Results of this study suggest possible rational utilization of the Smederevsko Pomoravlje lignites in thermal power plants. This is particularly related to samples from coal seam I. Significant amount of gas could be generated from lignites at higher maturities. Eight samples meet basic assumptions for effective gasification. [Projekat Ministarstva nauke Republike Srbije, br. 176006

  11. Field and synthetic experiments for virtual source crosswell tomography in vertical wells: Perth Basin, Western Australia

    Science.gov (United States)

    Almalki, Majed; Harris, Brett; Dupuis, J. Christian

    2013-11-01

    It is common for at least one monitoring well to be located proximally to a production well. This presents the possibility of applying crosswell technologies to resolve a range of earth properties between the wells. We present both field and synthetic examples of dual well walk-away vertical seismic profiling in vertical wells and show how the direct arrivals from a virtual source may be used to create velocity images between the wells. The synthetic experiments highlight the potential of virtual source crosswell tomography where large numbers of closely spaced receivers can be deployed in multiple wells. The field experiment is completed in two monitoring wells at an aquifer storage and recovery site near Perth, Western Australia. For this site, the crosswell velocity distribution recovered from inversion of travel times between in-hole virtual sources and receivers is highly consistent with what is expected from sonic logging and detailed zero-offset vertical seismic profiling. When compared to conventional walkaway vertical seismic profiling, the only additional effort required to complete dual-well walkaway vertical seismic profiling is the deployment of seismic sensors in the second well. The significant advantage of virtual source crosswell tomography is realised where strong near surface heterogeneity results in large travel time statics.

  12. Hydrocarbon charging histories of the Ordovician reservoir in the Tahe oil field, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    李纯泉; 陈红汉; 李思田; 张希明; 陈汉林

    2004-01-01

    The Ordovician reservoir of the Tahe oil field went through many tectonic reconstructions, and was characterized by multiple hydrocarbon chargings. The aim of this study was to unravel the complex charging histories. Systematic analysis of fluid inclusions was employed to complete the investigation. Fluorescence observation of oil inclusions under UV light, and microthermometry of both oil and aqueous inclusions in 105 core samples taken from the Ordovician reservoir indicated that the Ordovician reservoir underwent four oil chargings and a gas charging. The hydrocarbon chargings occurred at the late Hercynian, the Indo-Sinian and Yanshan, the early Himalaya, the middle Himalaya, and the late Himalaya,respectively. The critical hydrocarbon charging time was at the late Hercynian.

  13. Hydrocarbon charging histories of the Ordovician reservoir in the Tahe oil field, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    李纯泉; 陈红汉; 李思田; 张希明; 陈汉林

    2004-01-01

    The Ordovician reservoir of the Tahe oil field went through many tectonic reconstructions, and was charac-terized by multiple hydrocarbon chargings. The aim of this study was to unravel the complex charging histories. Systematicanalysis of fluid inclusions was employed to complete the investigation. Fluorescence observation of oil inclusions underUV light, and microthermometry of both oil and aqueous inclusions in 105 core samples taken from the Ordovician reservoirindicated that the Ordovician reservoir underwent four oil chargings and a gas charging. The hydrocarbon chargings oc-curred at the late Hercynian, the Indo-Sinian and Yanshan, the early Himalaya, the middle Himalaya, and the late Himalaya,respectively. The critical hydrocarbon charging time was at the late Hercynian.

  14. Stress field estimation based on focal mechanisms and back projected imaging in the Eastern Llanos Basin (Colombia)

    Science.gov (United States)

    Gómez-Alba, Sebastián; Fajardo-Zarate, Carlos Eduardo; Vargas, Carlos Alberto

    2016-11-01

    At least 156 earthquakes (Mw 2.8-4.4) were detected in Puerto Gaitán, Colombia (Eastern Llanos Basin) between April 2013 and December 2014. Out of context, this figure is not surprising. However, from its inception in 1993, the Colombian National Seismological Network (CNSN) found no evidence of significant seismic events in this region. In this study, we used CNSN data to model the rupture front and orientation of the highest-energy events. For these earthquakes, we relied on a joint inversion method to estimate focal mechanisms and, in turn, determine the area's fault trends and stress tensor. While the stress tensor defines maximum stress with normal tendency, focal mechanisms generally represent normal faults with NW orientation, an orientation which lines up with the tracking rupture achieved via Back Projection Imaging for the study area. We ought to bear in mind that this anomalous earthquake activity has taken place within oil fields. In short, the present paper argues that, based on the spatiotemporal distribution of seismic events, hydrocarbon operations may induce the study area's seismicity.

  15. Outcomes of pregnancy among women living in the proximity of oil fields in the Amazon basin of Ecuador.

    Science.gov (United States)

    San Sebastián, Miguel; Armstrong, Ben; Stephens, Carolyn

    2002-01-01

    Oil companies have released billions of gallons of untreated wastes and oil directly into the environment of the Ecuadorian Amazon. This cross-sectional study investigated the environmental conditions and reproductive health of women living in rural communities surrounded by oil fields in the Amazon basin and in unexposed communities. Water from local streams was analyzed for total petroleum hydrocarbons (TPH). The women, aged 17 to 45 years, had resided for at least three years in the study communities. Socioeconomic and reproductive histories of the last three pregnancies were obtained from interviews. Information from the questionnaire was available for 365 exposed and 283 non-exposed women. The study was conducted from November 1998 to April 1999. Streams of exposed communities had TPH concentrations above the allowable limit. After adjustment for potential confounders, the pregnancies of women in exposed communities were more likely to end in spontaneous abortion (OR: 2.47; 95% CI: 1.61-3.79; p pollution in the area is needed.

  16. Paleogeothermal Reconstruction and Thermal Evolution Modeling of Source Rocks in the Puguang Gas Field, Northeastern Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    Chuanqing Zhu; Nansheng Qiu; Huanyu Cao; Song Rao; Shengbiao Hu

    2016-01-01

    The thermal history and organic matter maturity evolution of the source rocks of boreholes in the Puguang gas field were reconstructed. An integrated approach based on vitrinite reflectance and apatite fission track data was used in the reconstruction. Accordingly, the geothermal conditions of gas accumulation were discussed in terms of the geological features of reservoirs in the northeastern Sichuan Basin. The strata reached their maximum burial depth in the Late Cretaceous era and were then uplifted and denuded continuously to the present day. The geothermal gradient and heat flow in the Late Cretaceous era were approximately 30.0 °C/km and 66 mW/m2, respectively, which were both higher than those at present. The tectonothermal evolution from the Late Cretaceous era to the present is characterized by denudation and cooling processes with an erosion thickness of~2.7 km. In addition to the Triassic era, the Jurassic era represents an important hydrocarbon generation period for both Silurian and Permian source rocks, and the organic matter maturity of these source rocks entered into a dry gas period after oil generation. The thermal conditions are advantageous to the accumulation of conventional and unconventional gas because the hydrocarbon generation process of the source rocks occurs after the formation of an effective reservoir cap. In particular, the high geothermal gradient and increasing temperature before the denudation in the Late Cretaceous era facilitated the generation of hydrocarbons, and the subsequent cooling process favored its storage.

  17. Organic geochemical study of the ''W'' oil-gas field in the Yugoslav part of the Pannonian basin

    Energy Technology Data Exchange (ETDEWEB)

    Saban, M.M. (Belgrade Univ. (Yugoslavia). Faculty of Chemistry Institute of Chemistry, Technology and Metallurgy, Belgrade (Yugoslavia)); Jovancicevic, B.S.; Glumicic, T. (Institute of Chemistry, Technology and Metallurgy, Belgrade (Yugoslavia)); Saracevic, S. (Nafta-gas, Novi Sad (Yugoslavia))

    1990-01-01

    The naphthenic crude oil from the ''W'' oil-gas field differs from almost all other, paraffinic base oils discovered until now in the Yugoslav part of the Pannonian basin. In order to explain this difference, some geological and organic geochemical investigations were carried out. On the basis of the bulk and biomarker parameters, determined in oil samples taken from 13 producing wells located at different parts of the field, it is concluded that the crude oil throughout the field has an almost uniform composition. (author)

  18. Electrofacies vs. lithofacies sandstone reservoir characterization Campanian sequence, Arshad gas/oil field, Central Sirt Basin, Libya

    Science.gov (United States)

    Burki, Milad; Darwish, Mohamed

    2017-06-01

    The present study focuses on the vertically stacked sandstones of the Arshad Sandstone in Arshad gas/oil field, Central Sirt Basin, Libya, and is based on the conventional cores analysis and wireline log interpretation. Six lithofacies types (F1 to F6) were identified based on the lithology, sedimentary structures and biogenic features, and are supported by wireline log calibration. From which four types (F1-F4) represent the main Campanian sandstone reservoirs in the Arshad gas/oil field. Lithofacies F5 is the basal conglomerates at the lower part of the Arshad sandstones. The Paleozoic Gargaf Formation is represented by lithofacies F6 which is the source provenance for the above lithofacies types. Arshad sediments are interpreted to be deposited in shallow marginal and nearshore marine environment influenced by waves and storms representing interactive shelf to fluvio-marine conditions. The main seal rocks are the Campanian Sirte shale deposited in a major flooding events during sea level rise. It is contended that the syn-depositional tectonics controlled the distribution of the reservoir facies in time and space. In addition, the post-depositional changes controlled the reservoir quality and performance. Petrophysical interpretation from the porosity log values were confirmed by the conventional core measurements of the different sandstone lithofacies types. Porosity ranges from 5 to 20% and permeability is between 0 and 20 mD. Petrophysical cut-off summary of the lower part of the clastic dominated sequence (i. e. Arshad Sandstone) calculated from six wells includes net pay sand ranging from 19.5‧ to 202.05‧, average porosity from 7.7 to 15% and water saturation from 19 to 58%.

  19. Optimization techniques for the secondary development of old gas fields in the Sichuan Basin and their application

    Directory of Open Access Journals (Sweden)

    Chongshuang Xia

    2016-12-01

    Full Text Available After nearly 60 years of development, many old gas fields in the Sichuan Basin have come to middle–late development stages with low pressure and low yield, and some are even on the verge of abandonment, but there are plenty remaining gas resources still undeveloped. Analysis shows that gas fields which have the conditions for the secondary development are faced with many difficulties. For example, it is difficult to produce low permeable reserves and to unset the hydraulic seal which is formed by active formation water. In this paper, therefore, the technical route and selection conditions of old gas fields for the secondary development were comprehensively elaborated with its definition as the beginning. Firstly, geological model forward modeling and production performance inversion characteristic curve diagnosis are performed by using the pressure normalization curve and the identification and quantitative description method for multiple sets of storage–seepage body of complex karst fracture–cavity systems is put forward, after the multiple storage–seepage body mode of fracture–cavity systems is established. Combined with the new occurrence mode of gas and water in U-shape pipes, a new calculation technology for natural gas reserves of multiple fracture–cavity systems with strong water invasion is developed. Secondly, a numerical model of pore–cavity–fracture triple media is built, and simulation and result evaluation technology for the production pattern of “drainage by horizontal wells + gas production by vertical wells” in bottom-water fracture and cavity gas reservoirs with strong water invasion is developed. Thirdly, the geological model of gas reservoirs is reconstructed with the support of the integration technologies which are formed based on fine gas reservoir description. Low permeable reserves of gas reservoirs are evaluated based on each classification. The effective producing ratio is increased further by

  20. Winter Irrigation Effects in Cotton Fields in Arid Inland Irrigated Areas in the North of the Tarim Basin, China

    Directory of Open Access Journals (Sweden)

    Pengnian Yang

    2016-02-01

    Full Text Available Winter irrigation is one of the water and salt management practices widely adopted in arid irrigated areas in the Tarim Basin located in the Xinjiang Uygur Autonomous Region in the People’s Republic of China. A winter irrigation study was carried out from November 2013 to March 2014 in Korla City. A cotton field was divided into 18 plots with a size of 3 m × 3 m and five winter irrigation treatments (1200 m3/ha, 1800 m3/ha, 2400 m3/ha, 3000 m3/ha, and 3600 m3/ha and one non-irrigation as a control were designed. The results showed that the higher winter irrigation volumes allowed the significant short-term difference after the irrigation in the fields with the higher soil moisture content. Therefore, the soil moisture in the next sowing season could be maintained at the level which was slightly lower than field capacity and four times that in the non-irrigation treatment. The desalination effect of winter irrigation increased with the increase of water irrigation volume, but its efficiency decreased with the increase of water irrigation volume. The desalination effect was characterized by short-term desalination, long-term salt accumulation, and the time-dependent gradually decreasing trend. During the winter irrigation period, air temperature was the most important external influencing factor of the soil temperature. During the period of the decrease in winter temperatures from December to January, soil temperature in the 5-cm depth showed no significant difference in all the treatments and the control. However, during the period of rising temperatures from January to March, soil temperature in the control increased significantly, faster than that in all treatments. Under the same irrigation volume, the temperature difference between the upper soil layer and the lower soil layer increased during the temperature drop period and decreased during the temperature rise period. In this paper, we proposed the proper winter irrigation volume of 1800

  1. Geographic information system (GIS)-based maps of Appalachian basin oil and gas fields: Chapter C.2 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Ryder, Robert T.; Kinney, Scott A.; Suitt, Stephen E.; Merrill, Matthew D.; Trippi, Michael H.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    One of the more recent maps of Appalachian basin oil and gas fields (and the adjoining Black Warrior basin) is the U.S. Geological Survey (USGS) compilation by Mast and others (1998) (see Trippi and others, this volume, chap. I.1). This map is part of a larger oil and gas field map for the conterminous United States that was derived by Mast and others (1998) from the Well History Control System (WHCS) database of Petroleum Information, Inc. (now IHS Energy Group). Rather than constructing the map from the approximately 500,000 proprietary wells in the Appalachian and Black Warrior part of the WHCS database, Mast and others (1998) subdivided the region into a grid of 1-mi2 (square mile) cells and allocated an appropriate type of hydrocarbon production (oil production, gas production, oil and gas production, or explored but no production) to each cell. Each 1-mi2 cell contains from 0 to 5 or more exploratory and (or) development wells. For example, if the wells in the 1-mi2 cell consisted of three oil wells, one gas well, and one dry well, then the cell would be characterized on the map as an area of oil and gas production. The map by Mast and others (1998) accurately shows the distribution and types of hydrocarbon accumulation in the Appalachian and Black Warrior basins, but it does not show the names of individual fields. To determine the locality and name of individual oil and gas fields, one must refer to State oil and gas maps (for example, Harper and others, 1982), which are generally published at scales of 1:250,000 or 1:500,000 (see References Cited), and (or) published journal articles.

  2. Coal and coalbed-methane resources in the Appalachian and Black Warrior basins: maps showing the distribution of coal fields, coal beds, and coalbed-methane fields: Chapter D.1 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Trippi, Michael H.; Ruppert, Leslie F.; Milici, Robert C.; Kinney, Scott A.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    The maps contained in this chapter show the locations of coal fields, coal beds assessed by the U.S. Geological Survey (USGS) in 2000, and coalbed-methane fields in the central and southern Appalachian basin study areas, which include the coal-producing parts of the Black Warrior basin. The maps were compiled and modified from a variety of sources such as Tully (1996), Northern and Central Appalachian Basin Coal Regions Assessment Team (2001), Hatch and others (2003), Milici (2004), and unpublished data from the State geological surveys of Pennsylvania, West Virginia, Virginia, and Alabama. The terms “coalbed methane” and “coal-bed gas” are used interchangeably in this report. All of the figures are located at the end of this report.

  3. USING CABLE SUSPENDED SUBMERSIBLE PUMPS TO REDUCE PRODUCTION COSTS TO INCREASE ULTIMATE RECOVERY IN THE RED MOUNTAIN FIELD IN SAM JUAN BASIN REGION

    Energy Technology Data Exchange (ETDEWEB)

    Don L. Hanosh

    2004-08-01

    A joint venture between Enerdyne LLC, a small independent oil and gas producer, and Pumping Solutions Inc., developer of a low volume electric submersible pump, suspended from a cable, both based in Albuquerque, New Mexico, has re-established marginal oil production from the Red Mountain Oil Field, located in the San Juan Basin, New Mexico by working over 17 existing wells and installing submersible pumps.

  4. Division of Gas Accumulation System and Laws Controlling Distribution of Natural Gas in Typical Petroliferous Basins of China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Considering the existing problems of the petroleum system, this paper brings forward the concept of natural gas accumulation system and presents the dividing principles. Then detailed statistics on the accumulation factors of the 32 typical natural gas accumulation systems in China and studies on the laws controlling distribution of gas are collected. The research shows that the petroleum accumulation system is the basic unit controlling petroleum generation, migration and accumulation. Generating intensity, generating amount, accumulating efficiency and migration distance plays an important role in the distribution of natural gas. Through analysis on results of resources evaluation, discovered reserves and residual reserves, potential areas in middle-scaled petroliferous basins in China are forecasted in this paper. Ordos, Sichuan, Tarim and Qaidam basins are found out to be the main basins developing and enriching gas accumulation systems.

  5. Modeling forest carbon and nitrogen cycles based on long term carbon stock field measurement in the Delaware River Basin

    Science.gov (United States)

    Xu, B.; Pan, Y.; McCullough, K.; Plante, A. F.; Birdsey, R.

    2015-12-01

    Process-based models are a powerful approach to test our understanding of biogeochemical processes, to extrapolate ground survey data from limited plots to the landscape scale and to simulate the effects of climate change, nitrogen deposition, elevated atmospheric CO2, increasing natural disturbances and land use change on ecological processes. However, in most studies, the models are calibrated using ground measurements from only a few sites, though they may be extrapolated to much larger areas. Estimation accuracy can be improved if the models are parameterized using long-term carbon stock data from multiple sites representative of the simulated region. In this study, vegetation biomass and soil carbon stocks, and changes in these stocks over a recent decade, were measured in 61 forested plots located in three small watersheds in the Delaware River Basin (DRB). On average, total vegetation biomass was 160.2 Mg C ha-1 and the soil carbon stock was 76.6 Mg C ha-1, measured during 2012-2014. The biomass carbon stock increased by 2.45 Mg C ha-1 yr-1 from 2001-2003 to 2012-2014. This dataset was subsequently used to parameterize the PnET-CN model at the individual plot basis, and averaged parameters among plots were then applied to generate new watershed-scale model parameters for each of the three watersheds. The parameterized model was further validated by the field measurements in each of the major forest types. The spatial distribution of forest carbon pools and fluxes in three watersheds were mapped based on the simulation results from the newly parameterized PnET-CN model. The model will also be run under different scenarios to test the effects of climate change, altered atmospheric composition, land use change, and their interactions within the three watersheds and across the whole DRB.

  6. Sedimentary Characterization of the Upper Paleozoic Coal-Bearing Tight Sand Strata, Daniudi Gas Field, Ordos Basin, China

    Institute of Scientific and Technical Information of China (English)

    Wei Du; Zaixing Jiang; Qing Li; Ying Zhang

    2016-01-01

    The coal-bearing strata of the Upper Paleozoic (from the Taiyuan Formation to the low-er member of the Shanxi Formation) are the most important units that have high gas production in the Daniudi gas field, which is a typical tight-sandstone reservoir with high heterogeneity in the Ordos Ba-sin, China. Based on an integrated investigation of well logs, cores, SEM and 3-D seismic data, we de-lineated the sedimentary facies of the coal-bearing strata and divided the succession into sequenced stratigraphic units of different depositional systems. A sedimentary hiatus was documented for the first time in the study area and forms the sequence boundary between the Lower Pennsylvanian Car-boniferous Taiyuan Formation (Ct1) and the Upper Pennsylvanian Carboniferous Taiyuan Formation (Ct2). The coal-bearing strata in Ct1 are indicative of a barrier coastal deposition system. Tidal chan-nels are identified by their fine-grained, cross-stratified character. The sands in the tidal channels are well sorted, and the quartz content is above 95%. The coalbed located beside the sandstone is thought to be a lagoon. Gas-bearing, coarse-grained sandstone in the coal-bearing strata spanning from the Ct2 to the lower members of the Shanxi Formation (P1s) is interpreted as a fluvial-dominated braided del-ta that is divided into four third-order sequences. The coal-bearing strata are composed of sandstone, mudstone and coalbed from base to top in each sequence. Braided-river deposits form the lowstand system tract (LST) within each sequence. A shelf and lake depositional environment containing dark gray mudstone forms the transgressive systems tract (TST). The highstand systems tract (HST) depo-sits form the swamp coalbed in each sequence.

  7. l475bs.m77t - MGD77 data file for Geophysical data from field activity L-4-75-BS in Bering Sea, Aleutian Basin, Alaska from 09/07/1975 to 09/18/1975

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-4-75-BS in Bering Sea, Aleutian Basin,...

  8. l475bs.m77t - MGD77 data file for Geophysical data from field activity L-4-75-BS in Bering Sea, Aleutian Basin, Alaska from 09/07/1975 to 09/18/1975

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-4-75-BS in Bering Sea, Aleutian Basin,...

  9. Paleomorphology of the upper part of the Macae formation, Namorado field, Campos basin; Paleomorfologia do intervalo superior da formacao Macae, Campo de Namorado, Bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Barboza, Eduardo Guimaraes [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias. Programa de Pos-Graduacao em Geociencias; Tomazelli, Luiz Jose; Ayup-Zouain, Ricardo Norberto [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias. Centro de Estudos de Geologia Costeira e Oceanica; Viana, Adriano Roessler [PETROBRAS, Rio de Janeiro, RJ (Brazil). Exploracao e Producao. Edificio Sede

    2004-07-01

    The Macae Formation (Late Albian-Turonian of the Campos Basin) is represented by a thick column of carbonate sediments whose deposition began soon after the evaporitic phase that marks the beginning of the marine occupation of the basin. The top of this interval is represented by an unconformity (Type I), indicative of a variation in the base level of the basin, on which the turbidities of the basal sequence of the Namorado Field were deposited. For a better understanding of the depositional geometry of these turbidities, the paleogeomorphology analysis demonstrated to be quite efficient. The method of work used for so was a combination among the seismic 3D visualization (VoxelGeo{sup R}), from the characterization of different physical attributes of the seismic signal, and the facies analysis of wells profiles of the referred field. The developed analysis allowed the individualization and the three-dimensional visualization of a sinuous paleochannel in the top of the interval, until then not described in previous interpretations of this depositional system. With the information coming from this study, a better understanding of the genesis of this accumulation can be reached, especially in the part regarding to the units of important economic character, represented by the turbidities deposits and whose occurrences are related with stages of relative lowering of the sea level. (author)

  10. A Conceptual Model to Link Anomalously High Temperature Gradients in the Cerros del Rio Volcanic Field to Regional Flow in the Espanola Basin, New Mexico

    Science.gov (United States)

    Fillingham, E. J.; Keller, S. N.; McCullough, K. R.; Watters, J.; Weitering, B.; Wilce, A. M.; Folsom, M.; Kelley, S.; Pellerin, L.

    2015-12-01

    Temperature-depth well data along with electromagnetic (EM) data were collected by students of the Summer of Applied Geophysics Experience (SAGE) 2015 field season in the Espanola Basin, New Mexico. The data from this year, in addition to data acquired since 2013, were used to construct a conceptual east-west cross-section of the Espanola Basin and the adjacent highlands in order to evaluate the regional flow system. Vertical geothermal gradients from several monitoring wells were measured using a thermistor. Anomalously warm geothermal gradients were mapped in the Cerros del Rio volcanic field in the basin just east of the Rio Grande. Temperature gradients are up to 70℃/km, while the background geothermal gradients in the Rio Grande rift zone generally show 28℃-35℃/km. This anomaly extends to the Buckman well field, which supplies water to the city of Santa Fe. Overpumping of this well field has led to subsidence in the past. However, discharge temperature plots indicate that the temperature gradients of the Buckman field may be rebounding as pumping is reduced. Audiomagnetotelluric (AMT) and transient electromagnetic (TEM) data were acquired in the vicinity of three monitoring wells. TEM and AMT methods complement each other with the former having depths of investigation of less than ten to hundreds of meters and AMT having depths of investigation comparable to the wells deeper than 500m. These datasets were used collectively to image the subsurface stratigraphy and, more specifically, the hydrogeology related to shallow aquifers. The EM data collected at these wells showed a trend indicating a shallow aquifer with a shallower resistive layer of approximately 100 ohm-m at 70-100 meters depth. Beneath this resistive layer we resolved a more conductive, clay-rich layer of 10 ohm-m. These resistivity profiles compliment the electrical logs provided by Jet West, which indicate shallower sandstone interbedded with silt on top of more silt-dominant layers. Our

  11. Increased oil production and reserves from improved completion techniques in the Bluebell Field, Uinta Basin, Utah. Seventh quarterly technical progress report, April 1, 1995--June 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, C.D.

    1995-09-01

    The objective of this project is to increase oil production and reserves in the Uinta Basin by demonstrating improved completion techniques. Low productivity of Uinta Basin wells is caused by gross production intervals of several thousand feet that contain perforated thief zones, water-bearing zones, and unperforated oil-bearing intervals. Geologic and engineering characterization and computer simulation of the Green River and Wasatch formations in the Bluebell field will determine reservoir heterogeneities related to fractures and depositional trends. This will be followed by drilling and recompletion of several wells to demonstrate improved completion techniques based on the reservoir characterization. Transfer of the project results will be an ongoing component of the project. Technical progress for this quarter are discussed for subsurface and engineering studies.

  12. Integrated geophysical studies on the area east of Abu Gharadig basin, southern Cairo, Egypt, using potential field data

    Science.gov (United States)

    El-Awady, Mohammed Mohamed; El-Badrawy, Hussein Tawfek; Abuo El-Ela, Amin Mohamed; Solimaan, Mohamed Refaat; Alrefaee, Hamed Abdelhamid; Elbowab, Mostafa

    2016-12-01

    Potential field data of the area east of Abu Gharadig basin were used to delineate the tectonic framework of probable economic interest and for future development plans for the area. To achieve this goal, the RTP and Bouguer gravity maps of the study area were subjected to several filtering and processing techniques. The regional magnetic map shows NE-SW high regional magnetic trends at the northwestern and southeastern parts as well as low magnetic trends at the central part reflecting thick non-magnetized sediments and/or deep highly magnetized basement rocks. Similarly, the regional gravity map shows NE-SW diagonal high and low gravity trends across the entire area of study as well as a distinct increase of gravity values toward the northwest corner reflecting thickening of sedimentary cover and/or deepening of denser basement rock at the central part. The residual maps reveal many anomalies of shallow sources with different polarities, amplitudes and extensions in the form of alternating high and low gravity and magnetic indicating that the basement rocks are dissected by faults forming uplifted and downthrown blocks. Edge detection techniques outlined effectively the boarders and extensions of the structural highs and lows through showing gravity and magnetic maxima over the edges of these tectonic features. Moreover, the River Nile course is controlled by shallow normal faults affecting the recent Nile sediments and is clearly shown by edge detection maps of gravity data. Euler deconvolution of magnetic and gravity data reveals clustering of solution along fault trends or causative bodies centers. The Euler depth estimate to the basement surface shows a good correlation with the depth determined by the power spectrum method where its value ranges around 4 km. The interpreted basement tectonic map of the study area is dominated by ENE-WSW Syrian Arc, NW-SE Gulf of Suez and Red Sea, NE-SW Aqaba, E-W Mediterranean and N-S East Africa tectonic trends. The older

  13. Quantitative seismic reservoir characterization of tight sands (granite wash) play at Stiles Ranch field in the Anadarko Basin, Texas (USA)

    Science.gov (United States)

    Durrani, Muhammad Zahid Afzal

    The main objective of this study is to conduct quantitative seismic reservoir characterization study of the Granite Wash (Marmaton-tight sand) play at Stiles Ranch field in the Anadarko Basin, Texas (USA). The proposed methodology incorporates seismic petrophysics, rock physics, Amplitude Variation with Offset (AVO) analysis and seismic pre-stack simultaneous elastic impedance inversion. In addition, it utilizes geostatistical technique to improve the reservoir property estimation and quantify uncertainty in seismic lithology and fluid prediction. The general objective encompasses several more specific goals to study: well data conditioning and prediction of essential petrophysical properties (e.g., porosity, permeability and saturation), and their relationship to the elastic properties. Due to the multidisciplinary nature of seismic petrophysics, only three core aspects are focused on that cover the desired objectives: 1) porosity modeling, 2) shear wave prediction, and (3) fluid substitution. The rock types are characterized by Rock Physics Diagnostic (RPD) approach conducted on well log data calibrated with core data and thin sections. The Granite Wash reservoir elastic properties are upscaled from log to seismic scale using Backus averaging to obtain a more coarsely (upscaled) sampled data set equivalent to the seismic scale. Anisotropy parametric (epsilon, gamma and delta) log curves are estimated consistent with seismic measurements using rock properties, seismic velocity and clay volume (Vsh) as a function of depth. The reservoir elastic properties are related to both the depositional environment and burial history through rock physics depth trends as function of depth. Furthermore, based on the practical aspects two separate inversion approaches; AVO and Elastic Impedance (EI) are evaluated prior to their application to real seismic. Various AVO derived attribute volumes such as intercept (A), gradient (B) and reflection coefficients (scaled Poisson's ratio

  14. Increased oil production and reserves from improved completion techniques in the Bluebell Field, Uinta Basin, Utah. Annual report, September 30, 1993--September 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Allison, M.

    1995-07-01

    The Bluebell field produces from the Tertiary lower Green River and Wasatch Formations of the Uinta Basin, Utah. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate beds deposited in a fluvial-dominated deltaic lacustrine environment, sandstones deposited in fluvial-dominated deltas; and carbonates and some interbedded sandstones of the lower Wasatch transition deposited in mud flats. Bluebell project personnel are studying ways to improve completion techniques used in the field to increase primary production in both new wells and recompletions. The study includes detailed petrographic examination of the different lithologic reservoir types in both the outcrop and core. Outcrop, core, and geophysical logs are being used to identify and map important depositional cycles. Petrographic detail will be used to improve log calculation methods which are currently highly questionable due to varying water chemistry and clay content in the Green River and Wasatch Formations. Field mapping of fractures and their relationship to basin tectonics helps predict the orientation of open fractures in the subsurface. The project includes acquiring bore-hole imaging logs from new wells in the Bluebell field thereby obtaining detailed subsurface fracture data previously not available. Reservoir simulation models are being constructed to improve the understanding of pressure and fluid flow within the reservoir. A detailed database of well completion histories has been compiled and will be studied to determine which were the most and the least effective methods used in the past.

  15. Was the Devonian geomagnetic field dipolar or multipolar? Palaeointensity studies of Devonian igneous rocks from the Minusa Basin (Siberia) and the Kola Peninsula dykes, Russia

    Science.gov (United States)

    Shcherbakova, V. V.; Biggin, A. J.; Veselovskiy, R. V.; Shatsillo, A. V.; Hawkins, L.; Shcherbakov, V. P.; Zhidkov, G. V.

    2017-02-01

    Defining variations in the behaviour of the geomagnetic field through geological time is critical to understanding the dynamics of Earth's core and its response to mantle convection and planetary evolution. Furthermore, the question of whether the axial dipole dominance of the recent palaeomagnetic field persists through the whole of Earth's history is fundamental to determining the reliability of palaeogeographic reconstructions and the efficacy of the magnetosphere in shielding Earth from solar wind radiation. Previous palaeomagnetic directional studies have suggested that the palaeofield had a complex configuration in the Devonian period (419-359 Ma). Here we present new palaeointensity determinations from rocks aged between 408 and 375 Ma from the Minusa Basin (southern Siberia), and the Kola Peninsula to investigate the strength of the field during this enigmatic period. Palaeointensity experiments were performed using the thermal Thellier, microwave Thellier, and Wilson methods on 165 specimens from 25 sites. Six out of eight successful sites from the Minusa Basin and all four successful sites from the Kola Peninsula produced extremely low palaeointensities (uniformitarian view of the palaeomagnetic field: field intensities of nearly an order of magnitude lower than Neogene values (except during relatively rare geomagnetic excursions and reversals) together with the widespread appearance of strange directions found in the Devonian suggest that the Earth's field during this time may have had a dominantly multipolar geometry. A persistent, low intensity multipolar magnetic field and associated diminished magnetosphere would increase the impact of solar particles on the Earth's magnetosphere, ionosphere and atmosphere with potential major implications for Earth's climate and biosphere.

  16. Arsenic bioaccumulation and biotransformation in deep-sea hydrothermal vent organisms from the PACMANUS hydrothermal field, Manus Basin, PNG

    Science.gov (United States)

    Price, Roy E.; Breuer, Christian; Reeves, Eoghan; Bach, Wolfgang; Pichler, Thomas

    2016-11-01

    Hydrothermal vents are often enriched in arsenic, and organisms living in these environments may accumulate high concentrations of this and other trace elements. However, very little research to date has focused on understanding arsenic bioaccumulation and biotransformation in marine organisms at deep-sea vent areas; none to date have focused organisms from back-arc spreading centers. We present for the first time concentration and speciation data for As in vent biota from several hydrothermal vent fields in the eastern Manus basin, a back-arc basin vent field located in the Bismark Sea, western Pacific Ocean. The gastropods Alviniconcha hessleri and Ifremeria nautilei, and the mussel Bathymodiolus manusensis were collected from diffuse venting areas where pH was slightly lower (6.2-6.8), and temperature (26.8-10.5 °C) and arsenic concentrations (169.5-44.0 nM) were higher than seawater. In the tissues of these organisms, the highest total measured As concentrations were in the gills of A. hessleri (5580 mg kg-1), with 721 mg kg-1 and 43 mg kg-1 in digestive gland and muscle, respectively. I. nautilei contained 118 mg kg-1 in the gill, 108 mg kg-1 in the digestive gland and 22 mg kg-1 in the muscle. B. manusensis contained 15.7 mg kg-1 in the digestive gland, followed by 9.8 mg kg-1 and 4.5 mg kg-1 in its gill and muscle tissue, respectively. We interpret the decreasing overall total concentrations in each organism as a function of distance from the source of hydrothermally derived As. The high concentration of arsenic in A. hessleri gills may be associated with elemental sulfur known to occur in this organism as a result of symbiotic microorganisms. Arsenic extracted from freeze-dried A. hessleri tissue was dominated by AsIII and AsV in the digestive gland (82% and 16%, respectively) and gills (97% AsIII, 2.3% AsV), with only 1.8% and 0.2% arsenobetaine (As-Bet) in the digestive gland and gills, respectively. However, the muscle contained substantial amounts of

  17. Gas genetic type and origin of hydrogen sulfide in the Zhongba gas field of the western Sichuan Basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Guangyou; Zhang Shuichang [Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083 (China)] [State Key Laboratory for Enhanced Oil Recovery, Beijing 100083 (China); Huang Haiping, E-mail: huah@ucalgary.ca [School of Energy Resource, China University of Geosciences, Beijing 100083 (China)] [Department of Geosciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4 (Canada); Liang Yingbo; Meng, Shucui [Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083 (China); Li Yuegang [Northwest Sichuan Gas Field, PetroChina Southwest Oil and Gas Field Company, Jiangyou, 621101 Sichuan (China)

    2011-07-15

    Highlights: > Natural gases discovered from the Zhongba gas field have two genetic types. > TSR is the main origin of H{sub 2}S. > Supportive evidences of TSR are derived from gas carbon isotopic values, sulfur isotopic values and formation water compositions. > Incomplete TSR reaction ceased in the Late Cretaceous. - Abstract: Natural gases and associated condensate oils from the Zhongba gas field in the western Sichuan Basin, China were investigated for gas genetic types and origin of H{sub 2}S by integrating gaseous and light hydrocarbon geochemistry, formation water compositions, S isotopes ({delta}{sup 34}S) and geological data. There are two types of natural gas accumulations in the studied area. Gases from the third member of the Middle Triassic Leikoupo Formation (T{sub 2}l{sup 3}) are reservoired in a marine carbonate sequence and are characterized by high gas dryness, high H{sub 2}S and CO{sub 2} contents, slightly heavy C isotopic values of CH{sub 4} and widely variable C isotopic values of wet gases. They are highly mature thermogenic gases mainly derived from the Permian type II kerogens mixed with a small proportion of the Triassic coal-type gases. Gases from the second member of the Upper Triassic Xujiahe Formation (T{sub 3}x{sup 2}) are reservoired in continental sandstones and characterized by low gas dryness, free of H{sub 2}S, slightly light C isotopic values of CH{sub 4}, and heavy and less variable C isotopic values of wet gases. They are coal-type gases derived from coal in the Triassic Xujiahe Formation. The H{sub 2}S from the Leikoupo Formation is most likely formed by thermochemical SO{sub 4} reduction (TSR) even though other possibilities cannot be fully ruled out. The proposed TSR origin of H{sub 2}S is supported by geochemical compositions and geological interpretations. The reservoir in the Leikoupo Formation is dolomite dominated carbonate that contains gypsum and anhydrite. Petroleum compounds dissolved in water react with aqueous SO

  18. Geochemistry of hydrothermal fluids from the PACMANUS, Northeast Pual and Vienna Woods hydrothermal fields, Manus Basin, Papua New Guinea

    Science.gov (United States)

    Reeves, Eoghan P.; Seewald, Jeffrey S.; Saccocia, Peter; Bach, Wolfgang; Craddock, Paul R.; Shanks, Wayne C.; Sylva, Sean P.; Walsh, Emily; Pichler, Thomas; Rosner, Martin

    2011-01-01

    Processes controlling the composition of seafloor hydrothermal fluids in silicic back-arc or near-arc crustal settings remain poorly constrained despite growing evidence for extensive magmatic-hydrothermal activity in such environments. We conducted a survey of vent fluid compositions from two contrasting sites in the Manus back-arc basin, Papua New Guinea, to examine the influence of variations in host rock composition and magmatic inputs (both a function of arc proximity) on hydrothermal fluid chemistry. Fluid samples were collected from felsic-hosted hydrothermal vent fields located on Pual Ridge (PACMANUS and Northeast (NE) Pual) near the active New Britain Arc and a basalt-hosted vent field (Vienna Woods) located farther from the arc on the Manus Spreading Center. Vienna Woods fluids were characterized by relatively uniform endmember temperatures (273-285 degrees C) and major element compositions, low dissolved CO2 concentrations (4.4 mmol/kg) and high measured pH (4.2-4.9 at 25 degrees C). Temperatures and compositions were highly variable at PACMANUS/NE Pual and a large, newly discovered vent area (Fenway) was observed to be vigorously venting boiling (358 degrees C) fluid. All PACMANUS fluids are characterized by negative delta DH2O values, in contrast to positive values at Vienna Woods, suggesting substantial magmatic water input to circulating fluids at Pual Ridge. Low measured pH (25 degrees C) values (~2.6-2.7), high endmember CO2 (up to 274 mmol/kg) and negative delta 34SH2S values (down to -2.7 permille) in some vent fluids are also consistent with degassing of acid-volatile species from evolved magma. Dissolved CO2 at PACMANUS is more enriched in 13C (-4.1 permille to -2.3 permille) than Vienna Woods (-5.2 permille to -5.7 permille), suggesting a contribution of slab-derived carbon. The mobile elements (e.g. Li, K, Rb, Cs and B) are also greatly enriched in PACMANUS fluids reflecting increased abundances in the crust there relative to the Manus

  19. Using High Resolution Satellite Precipitation fields to Assess the Impacts of Climate Change on the Santa Cruz and San Pedro River Basins

    Science.gov (United States)

    Robles-Morua, A.; Vivoni, E.; Rivera-Fernandez, E. R.; Dominguez, F.; Meixner, T.

    2013-05-01

    Hydrologic modeling using high spatiotemporal resolution satellite precipitation products in the southwestern United States and northwest Mexico is important given the sparse nature of available rain gauges. In addition, the bimodal distribution of annual precipitation also presents a challenge as differential climate impacts during the winter and summer seasons are not currently well understood. In this work, we focus on hydrological comparisons using rainfall forcing from a satellite-based product, downscaled GCM precipitation estimates and available ground observations. The simulations are being conducted in the Santa Cruz and San Pedro river basins along the Arizona-Sonora border at high spatiotemporal resolutions (~100 m and ~1 hour). We use a distributed hydrologic model, known as the TIN-based Real-time Integrated Basin Simulator (tRIBS), to generate simulated hydrological fields under historical (1991-2000) and climate change (2031-2040) scenarios obtained from an application of the Weather Research and Forecast (WRF) model. Using the distributed model, we transform the meteorological scenarios at 10-km, hourly resolution into predictions of the annual water budget, seasonal land surface fluxes and individual hydrographs of flood and recharge events. We compare the model outputs and rainfall fields of the WRF products against the forcing from the North American Land Data Assimilation System (NLDAS) and available ground observations from the National Climatic Data Center (NCDC) and Arizona Meteorological Network (AZMET). For this contribution, we selected two full years in the historical period and in the future scenario that represent wet and dry conditions for each decade. Given the size of the two basins, we rely on a high performance computing platform and a parallel domain discretization with higher resolutions maintained at experimental catchments in each river basin. Model simulations utilize best-available data across the Arizona-Sonora border on

  20. Production history matching to determine reservoir properties of important coal groups in the Upper Pottsville formation, Brookwood and Oak Grove fields, Black Warrior Basin, Alabama.

    Science.gov (United States)

    Karacan, C Özgen

    2013-01-01

    The Black Warrior Basin of Alabama is one of the most important coal mining and coalbed methane production areas in the United States. Methane control efforts through degasification that started almost 25 years ago for the sole purpose of ensuring mining safety resulted in more than 5000 coalbed methane wells distributed within various fields throughout the basin. The wells are completed mostly in the Pratt, Mary Lee, and Black Creek coal groups of the Upper Pottsville formation and present a unique opportunity to understand methane reservoir properties of these coals and to improve their degasification performances. The Brookwood and Oak Grove fields in the Black Warrior Basin are probably two of the most important fields in the basin due to current longwall coal mining activities. In this work, methane and water productions of 92 vertical wellbores drilled, some completed 20 years ago, over a current large coal mine district located in these two fields, were analyzed by history matching techniques. The boreholes were completed at the Mary Lee coal group, or at combinations of the Pratt, Mary Lee, and Black Creek groups. History matching models were prepared and performed according to properties of each coal group. Decline curve analyses showed that effective exponential decline rates of the wells were between 2% and 25% per year. Results of production history matching showed, although they varied by coal group, that pressure decreased as much as 80% to nearly 25 psi in some areas and resulted in corresponding decreases in methane content. Water saturation in coals decreased from 100% to between 20 and 80%, improving gas relative permeabilities to as much as 0.8. As a result of primary depletion, permeability of coal seams increased between 10 and 40% compared to their original permeability, which varied between 1 and 10 md depending on depth and coal seam. These results not only can be used for diagnostic and interpretation purposes, but can be used as parameter

  1. From Flysch to Molasse-Sedimentary and Tectonic Evolution of Late Caledonian-Early Hercynian Foreland Basin in North Qilian Mountains

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Late Caledonian to Early Hercynian North Qilian orogenic belt in northwestern China is an elongate tectonic unit situated between the North China plate in the north and the Qaidam plate in the south. North Qilian started in the latest Proterozoic to Cambrian as a rift basin on the southern margin of North China, and evolved later to an archipelagic ocean and active continental margin during the Ordovician and a foreland basin from Silurian to the Early and Middle Devonian. The Early Silurian flysch and submarine alluvial fan, the Middle to Late Silurian shallow marine to tidal flat deposits and the Early and Middle Devonian terrestrial molasse are developed along the corridor Nanshan. The shallowing-upward succession from subabyssal flysch, shallow marine, tidal flat to terrestrial molasse and its gradually narrowed regional distribution demonstrate that the foreland basin experienced the transition from flysch stage to molasse stage during the Silurian and Devonian time.

  2. 中国大陆地区沉积盆地的热状况、热历史和生烃史%Geothermal Regime, Thermal History and Hydrocarbon Generation Types of Sedimentary Basins in the Continental Area of China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The thermal regimes in sedimentary basins in the continental area of China are varied and reflect differences in geological settings. As a result of these variable thermal regimes, the history of hydrocarbon generation in each basin is also different. An east-west profile of the thermal threshold across the continental basins of China, like the Liaohe Basin, the North China Basin, the Ordos Basin, the Qaidam Basin and the Tarim Basin, was constructed using large numbers of heat flow measurements, temperature data and rock thermophysical parameters. Isotherms, surface heat flow,mantle heat flow and Moho temperature beneath the basins are shown in the profile, which illustrates changes in some thermal characteristics between basins in east China and those in west China. Thermal evolution histories in basins were reconstructed using Easy%Ro method, apatite fission track annealing and other paleothermometers. Typical hydrocarbon generation histories of the primary source rocks were modeled by referring to the thermal evolution data. Thermal stages controlled source rocks maturation and oil and gas generation, and influenced the type of hydrocarbon (oil and gas)production in the basins.

  3. USING CABLE SUSPENDED SUBMERSIBLE PUMPS TO REDUCE PRODUCTION COSTS TO INCREASE ULTIMATE RECOVERY IN THE RED MOUNTAIN FIELD OF THE SAN JUAN BASIN REGION

    Energy Technology Data Exchange (ETDEWEB)

    Don L. Hanosh

    2004-11-01

    This report discusses: (1) being able to resume marginal oil production operations in the Red Mountain Oil Field, located in McKinley County, New Mexico by installing a cable suspended electric submersible pumping system (HDESP); (2) determining if this system can reduce life costs making it a more cost effective production system for similar oil fields within the region, and if warranted, drill additional wells to improve the economics. In April 2003, a cooperative 50% cost share agreement between Enerdyne and the DOE was executed to investigate the feasibility of using cable suspended electric submersible pumps to reduce the life costs and increase the ultimate oil recovery of the Red Mountain Oil Field, located on the Chaco Slope of the San Juan Basin, New Mexico. The field was discovered in 1934 and has produced approximately 55,650 cubic meters (m{sup 3}), (350,000 barrels, 42 gallons) of oil. Prior to April 2003, the field was producing only a few cubic meters of oil each month; however, the reservoir characteristics suggest that the field retains ample oil to be economic. This field is unique, in that, the oil accumulations, above fresh water, occur at depths from 88-305 meters, (290 feet to 1000 feet), and serves as a relatively good test area for this experiment.

  4. Mapping wetlands in the Lower Mekong Basin for wetland resource and conservation management using Landsat ETM images and field survey data.

    Science.gov (United States)

    MacAlister, Charlotte; Mahaxay, Manithaphone

    2009-05-01

    The Mekong River Basin is considered to be the second most species rich river basin in the world. The 795,000 km(2) catchment encompasses several ecoregions, incorporating biodiverse and productive wetland systems. Eighty percent of the rapidly expanding population of the Lower Mekong Basin (LMB), made up in part by Lao PDR, Thailand, Cambodia and Viet Nam, live in rural areas and are heavily reliant on wetland resources. As the populations of Cambodia and Lao PDR will double in the next 20 years, pressure on natural resources and particularly wetlands can only increase. For development planning, resource and conservation management to incorporate wetland issues, information on the distribution and character of Mekong wetlands is essential. The existing but outdated wetland maps were compiled from secondary landuse-landcover data, have limited coverage, poor thematic accuracy and no meta-data. Therefore the Mekong River Commission (MRC) undertook to produce new wetland coverage for the LMB. As resources, funding and regional capacity are limited, it was determined that the method applied should use existing facilities, be easily adaptable, and replicable locally. For the product to be useful it must be accepted by local governments and decision makers. The results must be of acceptable accuracy (>75%) and the methodology should be relatively understandable to non-experts. In the first stage of this exercise, field survey was conducted at five pilot sites covering a range of typical wetland habitats (MRC wetland classification) to supply data for a supervised classification of Landsat ETM images from the existing MRC archive. Images were analysed using ERDAS IMAGINE and applying Maximum Likelihood Classification. Field data were reserved to apply formal accuracy assessment to the final wetland habitat maps, with resulting accuracy ranging from 77 to 94%. The maps produced are now in use at a Provincial and National level in three countries for resource and

  5. A field-based method to derive macroinvertebrate benchmark for specific conductivity adapted for small data sets and demonstrated in the Hun-Tai River Basin, Northeast China.

    Science.gov (United States)

    Zhao, Qian; Jia, Xiaobo; Xia, Rui; Lin, Jianing; Zhang, Yuan

    2016-09-01

    Ionic mixtures, measured as specific conductivity, have been increasingly concerned because of their toxicities to aquatic organisms. However, identifying protective values of specific conductivity for aquatic organisms is challenging given that laboratory test systems cannot examine more salt-intolerant species nor effects occurring in streams. Large data sets used for deriving field-based benchmarks are rarely available. In this study, a field-based method for small data sets was used to derive specific conductivity benchmark, which is expected to prevent the extirpation of 95% of local taxa from circum-neutral to alkaline waters dominated by a mixture of SO4(2-) and HCO3(-) anions and other dissolved ions. To compensate for the smaller sample size, species level analyses were combined with genus level analyses. The benchmark is based on extirpation concentration (XC95) values of specific conductivity for 60 macroinvertebrate genera estimated from 296 sampling sites in the Hun-Tai River Basin. We derived the specific conductivity benchmark by using a 2-point interpolation method, which yielded the benchmark of 249 μS/cm. Our study tailored the method that was developed by USEPA to derive aquatic life benchmark for specific conductivity for basin scale application, and may provide useful information for water pollution control and management.

  6. Potential field studies of the central San Luis Basin and San Juan Mountains, Colorado and New Mexico, and southern and western Afghanistan

    Science.gov (United States)

    Drenth, Benjamin John

    This dissertation includes three separate chapters, each demonstrating the interpretive utility of potential field (gravity and magnetic) geophysical datasets at various scales and in various geologic environments. The locations of these studies are the central San Luis Basin of Colorado and New Mexico, the San Juan Mountains of southwestern Colorado, and southern and western Afghanistan. The San Luis Basin is the northernmost of the major basins that make up the Rio Grande rift, and interpretation of gravity and aeromagnetic data reveals patterns of rifting, rift-sediment thicknesses, distribution of pre-rift volcanic and sedimentary rocks, and distribution of syn-rift volcanic rocks. Syn-rift Santa Fe Group sediments have a maximum thickness of ˜2 km in the Sanchez graben near the eastern margin of the basin along the central Sangre de Cristo fault zone. Under the Costilla Plains, thickness of these sediments is estimated to reach ˜1.3 km. The Santa Fe Group sediments also reach a thickness of nearly 1 km within the Monte Vista graben near the western basin margin along the San Juan Mountains. A narrow, north-south-trending structural high beneath San Pedro Mesa separates the graben from the structural depression beneath the Costilla Plains. Aeromagnetic anomalies are interpreted to mainly reflect variations of remanent magnetic polarity and burial depth of the 5.3-3.7 Ma Servilleta basalt of the Taos Plateau volcanic field. Magnetic-source depth estimates indicate patterns of subsidence following eruption of the basalt and show that the Sanchez graben has been the site of maximum subsidence. One of the largest and most pronounced gravity lows in North America lies over the rugged San Juan Mountains in southwestern Colorado. A buried, low-density silicic batholith related to an Oligocene volcanic field coincident with the San Juan Mountains has been the accepted interpretation of the source of the gravity low since the 1970s. However, this interpretation was

  7. Increased oil production and reserves from improved completion techniques in the Bluebell Field, Uinta Basin, Utah. Annual report, October 1, 1994--September 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Allison, M.L.; Morgan, C.D.

    1996-05-01

    The Bluebell field produces from the Tertiary lower Green River and Wasatch Formations of the Uinta Basin, Utah. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate beds deposited in a fluvial-dominated deltaic lacustrine environment. Wells in the Bluebell field are typically completed by perforating 40 or more beds over 1,000 to 3,000 vertical feet (300-900 m), then applying an acid-fracture stimulation treatment to the entire interval. This completion technique is believed to leave many potentially productive beds damaged and/or untreated, while allowing water-bearing and low-pressure (thief) zones to communicate with the wellbore. Geologic and engineering characterization has been used to define improved completion techniques. The study identified reservoir characteristics of beds that have the greatest long-term production potential.

  8. Secondary natural gas recovery: Targeted applications for infield reserve growth in midcontinent reservoirs, Boonsville Field, Fort Worth Basin, Texas. Topical report, May 1993--June 1995

    Energy Technology Data Exchange (ETDEWEB)

    Hardage, B.A.; Carr, D.L.; Finley, R.J.; Tyler, N.; Lancaster, D.E.; Elphick, R.Y.; Ballard, J.R.

    1995-07-01

    The objectives of this project are to define undrained or incompletely drained reservoir compartments controlled primarily by depositional heterogeneity in a low-accommodation, cratonic Midcontinent depositional setting, and, afterwards, to develop and transfer to producers strategies for infield reserve growth of natural gas. Integrated geologic, geophysical, reservoir engineering, and petrophysical evaluations are described in complex difficult-to-characterize fluvial and deltaic reservoirs in Boonsville (Bend Conglomerate Gas) field, a large, mature gas field located in the Fort Worth Basin of North Texas. The purpose of this project is to demonstrate approaches to overcoming the reservoir complexity, targeting the gas resource, and doing so using state-of-the-art technologies being applied by a large cross section of Midcontinent operators.

  9. Study of fault configuration related mysteries through multi seismic attribute analysis technique in Zamzama gas field area, southern Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi

    2016-03-01

    Full Text Available Seismic attribute analysis approach has been applied for the interpretation and identification of fault geometry of Zamzama Gas Field. Zamzama gas field area, which lies in the vicinity of Kirthar fold and thrust belt, Southern Indus Basin of Pakistan. The Zamzama fault and its related structure have been predicted by applying the Average Energy Attribute, Instantaneous Frequency Attribute, relative Acoustic Impedance Attribute and Chaotic Reflection Attribute on the seismic line GHPK98A.34. The results have been confirmed by applying the spectral decomposition attribute on the same seismic line that reveal the geometric configuration of Zamzama structure. The fault is reverse and started from 0 s and ended at the depth of 2.5 s on the vertical seismic section. Hanging wall moves up along the fault plane under the action of eastward oriented stress, which formed a large north–south oriented and eastward verging thrusted anticline.

  10. 2 D seismic sections interpretation for the Xareu field in the Mundau sub-basin (Ceara basin, Northeastern Brazil); Interpretacao de secoes sismicas 2D para o Campo de Xareu na sub-bacia de Mundau (Bacia do Ceara, NE do Brasil)

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Alex Francisco [Rio Grande do Norte Univ., Natal, RN (Brazil)]. E-mail: alex@geologia.ufrn.br; Jardim de Sa, Emanuel Ferraz [Rio Grande do Norte Univ., Natal, RN (Brazil). Programa de Pos-graduacao em Geodinamica e Geofisica; Matos, Renato Marcos Darros de [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Geologia; Keller Filho, Odilon [PETROBRAS S.A., Natal, RN (Brazil). Unidade de Negocios RN/CE; Lima Neto, Francisco Fontes [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2003-07-01

    This paper presents a reinterpretation of seismic sections of the Xareu Oil Field, located in the central portion of the Mundau Sub-basin (Ceara Basin, Northeast Brazil). These seismic sections were acquired during the 80's and the 90's. Their reinterpretation show that the field is structured by a main arrangement of N W-trending listric normal faults, with associated roll-over structures affecting the rocks of the rift (Mundau Formation) and transitional (Paracuru Formation) sections of the basin. Some of these faults also affect the basal and intermediate layers of the drift section (Ubarana Formation), what denotes their reactivation (or even the formation of new faults). the new interpretation allows a better understanding of the frequency, geometry, orientation, style and kinematic of the faults, important factors in the structural characterization of the Xareu Oil Field. (author)

  11. Process and.mechanism for oil and gas accumulation,adjustment and reconstruction in Puguang Gas Field,Northeast Sichuan Basin,China

    Institute of Scientific and Technical Information of China (English)

    DU ChunGuo; HAO Fang; ZOU HuaYao; ZHU YangMing; CAI XunYu; WANG CunWu

    2009-01-01

    With the discoveries of a series of large gas fields in the northeast of Sichuan Basin,such as Puguang and Longgang gas fields,the formation mechanism of the gas reservoir containing high H2S in the ancient marine carbonate formation in superposition-basin becomes a hot topic in the field of petroleum geology.Based on the structure inversion,numerical simulation,and geochemical research,we show at least two intervals of fluid transfer in Puguang paleo-oil reservoir,one in the forepart of late Indo-Chinese epoch to early Yanshan epoch and the other in the metaphase of early Yanshan epoch.Oil and gas accumulation occurred at Puguang structure through Puguang-Dongyuezhai faults and dolomite beds in reef and shoal facies in Changxing Formation (P2ch) - Feixianguan Formation (T1f) in the northwest and southwest directions along three main migration pathways,to form Puguang paleo-oil reservoir.Since crude oil is pyrolysised in the early stage of middle Yanshan epoch,Puguang gas reservoir has experienced fluid adjusting process controlled by tectonic movement and geochemical reconstruction process controlled by thermochemical sulfate reduction (TSR).Middle Yanshan epoch is the main period during which the Puguang gas reservoir experienced the geochemical reaction of TSR.On one hand,TSR can recreate the fluid in gas reservoir,which makes the gas drying index larger and carbon isotope heavier.On the other hand,the reciprocity between fluid regarding TSR (hydrocarbon,H2S,and water) and reservoir rock induces erosion of the reservoir rocks and anhydrite alteration,which improves reservoir petrophysical properties.Superimposed by later tectonic movement,the fluid in Puguang reservoir has twice experienced adjustment,one in the late Yanshan epoch to the early Himalayan epoch and the other time in late Himalayan epoch,after which Puguang gas reservoir is finally developed.

  12. Geothermal resources characteristics of Shilin basin geothermal field in Yunnan province%云南石林盆地地热田地热资源特征

    Institute of Scientific and Technical Information of China (English)

    姚明波; 刘红战; 陈康

    2013-01-01

    石林是国家地质公园,位于滇东断陷盆地,其地热研究是对云南断陷盆地地热研究的理论论证.论文通过对石林地热的热源、热田结构、水文地质特征、水化学特征进行研究,地热类型为深循环层状地热田,受九乡-石垭口断裂和牛头山古陆控制,形成封闭的层状低温地热田.从水文地质条件看,地下热水水化学类型为HCO3-Ca,偏硅酸含量较高.地热热储层埋藏深,水温45 ~51℃,地下热水具承压性,宜于开采利用.但热田水补给资源有限,且上部冷水丰富,应控制地热水的开发利用.该研究成果对滇东其他岩溶断陷盆地地热开发有应用和参考价值.%Shilin is a national geological park which is located in eastern Yunnan basin.The study on its geothermal is the theoretical demonstration of Yunnan rift basin geothermal.This paper studied the geothermal type,geothermal field structure,hydrogeological characteristics and water chemistry characteristics.The geothermal type belongs to deep cycle layered geothermal field and controlled by Jiyxiang-Shiyakou fault and Niutoushan ancient land so as to form the low temperature geothermal field of close layered.According to the hydrogeological conditions,the chemical type of geothermal water is HCO3-Ca with high silicic acid content.As the geothermal reservoir is deeply buried,its water temperature is from 45 to 51 centigrade and with pressure-bearing,the underground hot water is suitable to exploit.While the resources supply is limited and the upper cold water is rich,the development and utilization of geothermal water should be controled.The result has application and reference value for the development of other eastern Yunnan karst rift basins.

  13. Increased oil production and reserves from improved completion techniques in the Bluebell field, Uinta Basin, Utah. Tenth quarterly technical progress report, January 1, 1996--March 31, 1996. Revised

    Energy Technology Data Exchange (ETDEWEB)

    Allison, M.L.

    1996-05-13

    The objective of this project is to increase oil production and reserves in the Uinta Basin by demonstrating improved completion techniques. Low productivity of Uinta Basin will is caused by gross production intervals of several thousand feet that contain perforated thief zones, water-bearing zones, and unperforated oil- bearing intervals. Geologic and engineering characterization and computer simulation of the Green River and Wasatch Formations in the Bluefell field will determine reservoir heterogeneities related to fractures and depositional trends. This will be followed by techniques based on the reservoir characterization. Transfer of the project results will be an ongoing component of the project. Data (net pay thickness, porosity, and water saturation) of more than 100 individuals beds in he lower Green River and Wasatch Formations were used to generate geostatistical realization (numerical- representation) of the reservoir properties. The data set was derived from the Michelle Ute and Malnar Pike demonstration wells and 22 other wells in a 20 (52 km{sup 2}) square-mile area. Beds were studied independently of each other. Principles of sequential Gaussian simulations were used to generate geostatistical realizations of the beds.

  14. Estimating the spatial distribution of field-applied mushroom compost in the Brandywine-Christina River Basin using multispectral remote sensing

    Science.gov (United States)

    Moxey, Kelsey A.

    The world's greatest concentration of mushroom farms is settled within the Brandywine-Christina River Basin in Chester County in southeastern Pennsylvania. This industry produces a nutrient-rich byproduct known as spent mushroom compost, which has been traditionally applied to local farm fields as an organic fertilizer and soil amendment. While mushroom compost has beneficial properties, the possible over-application to farm fields could potentially degrade stream water quality. The goal of this study was to estimate the spatial extent and intensity of field-applied mushroom compost. We applied a remote sensing approach using Landsat multispectral imagery. We utilized the soil line technique, using the red and near-infrared bands, to estimate differences in soil wetness as a result of increased soil organic matter content from mushroom compost. We validated soil wetness estimates by examining the spectral response of references sites. We performed a second independent validation analysis using expert knowledge from agricultural extension agents. Our results showed that the soil line based wetness index worked well. The spectral validation illustrated that compost changes the spectral response of soil because of changes in wetness. The independent expert validation analysis produced a strong significant correlation between our remotely-sensed wetness estimates and the empirical ratings of compost application intensities. Overall, the methodology produced realistic spatial distributions of field-applied compost application intensities across the study area. These spatial distributions will be used for follow-up studies to assess the effect of spent mushroom compost on stream water quality.

  15. USING CABLE SUSPENDED SUBMERSIBLE PUMPS TO REDUCE PRODUCTION COSTS TO INCREASE ULTIMATE RECOVERY IN THE RED MOUNTAIN FIELD IN SAN JUAN BASIN REGION

    Energy Technology Data Exchange (ETDEWEB)

    Pat Fort; Don L. Hanosh

    2003-11-01

    A joint venture between Enerdyne LLC, a small independent oil and gas producer, and Pumping Solutions Inc., developer of a low volume electric submersible pump, suspended from a cable, both based in Albuquerque, New Mexico, has re-established marginal oil production from the Red Mountain Oil Field, located in the San Juan Basin, New Mexico by working over 17 existing wells and installing submersible pumps. Resume marginal oil production operations in the Red Mountain oil fields located in McKinley County, New Mexico by installing a cable suspended electric submersible pumping system (HDESP), determine if this system can reduce lift costs making it a more cost effective production system for similar oil fields within the region, and if warranted, drill additional wells to improved the economics. Three Phases of work have been defined in the DOE Form 4600.1 Notice of Financial Assistance Award for this project, in which the project objectives are to be attained through a joint venture between Enerdyne LLC (Enerdyne), owner and operator of the fields and Pumping Solutions Inc. (PSI), developer of the submersible pumping system. Upon analysis of the results of each Phase, the DOE will determine if the results justify the continuation of the project and approve the next Phase to proceed or terminate the project and request that the wells be plugged. This topical report shall provide the DOE with Phase I results and conclusions reached by Enerdyne and PSI.

  16. Detection of active hydrothermal vent fields in the Pescadero Basin and on the Alarcon Rise using AUV multibeam and CTD data

    Science.gov (United States)

    Caress, D. W.; Troni, G.; Clague, D. A.; Paduan, J. B.; Martin, J. F.; Thomas, H. J.; Thompson, D.; Conlin, D.; Martin, E. J.; meneses-Quiroz, E.; Nieves-Cardoso, C.; Angel Santa Rosa del Rio, M.

    2015-12-01

    The MBARI AUV D. Allan B. collected high resolution bathymetry, sidescan, and subbottom profiles along the neovolcanic zone of the Alarcon Rise and across the southern Pescadero Basin during 2012 and 2015 MBARI expeditions to the Gulf of California (GOC). The combination of high resolution multibeam bathymetry and seawater temperature data has proven effective in identifying active high temperature vent fields, as validated by inspection and sampling during ROV dives. The AUV carries a 200 kHz multibeam sonar, 110 kHz chirp sidescan sonar, a 1-6 kHz chirp subbottom profiler, and a conductivity, temperature and depth (CTD) sensor for ~17-hour duration missions. Flying at 5.4 km/hr at 50 m altitude, the processed AUV bathymetry has a 0.1 m vertical precision and a 1 m lateral resolution. Chimneys taller than 1.5 m are sufficiently distinctive to allow provisional identification. The CTD temperature data have a nominal 0.002°C accuracy. Following calculation of potential temperature and correcting for average local variation of potential temperature with depth, anomalies greater than 0.05 °C can be reliably identified using a spike detection filter. MBARI AUV mapping surveys are typically planned using a 150 m survey line spacing, so the CTD data may be collected as much as 75 m away from any vent plume source. Five active high temperature vent fields were discovered in the southern GOC, with the Auka Field in the southern Pescadero Basin, and the Ja Sít, Pericú, Meyibó, and Tzab-ek Fields along the Alarcon Rise. In all five cases, hydrothermal vent chimneys are readily identifiable in the multibeam bathymetry, and temperature anomalies are observed above background variability. Other apparent hydrothermal chimneys were observed in the bathmetry that did not exhibit water temperature anomalies; most of these were visited during ROV dives and confirmed to be inactive sites. The maximum water column anomalies are 0.13°C observed above the Meyibó field and 0.25

  17. USING CABLE SUSPENDED SUBMERSIBLE PUMPS TO REDUCE PRODUCTION COSTS TO INCREASE ULTIMATE RECOVERY IN THE RED MOUNTAIN FIELD IN SAN JUAN BASIN REGION

    Energy Technology Data Exchange (ETDEWEB)

    Don L. Hanosh

    2004-01-01

    A joint venture between Enerdyne LLC, a small independent oil and gas producer, and Pumping Solutions Inc., developer of a low volume electric submersible pump, suspended from a cable, both based in Albuquerque, New Mexico, has re-established marginal oil production from the Red Mountain Oil Field, located in the San Juan Basin, New Mexico by working over 17 existing wells and installing submersible pumps. The project was funded through a cooperative 50% cost sharing agreement between Enerdyne LLC and the National Energy Technology Laboratory (NETL), United States Department of Energy, executed on April 16, 2003. The total estimated cost for this first phase of the agreement was $386,385.00 as detailed in Phase I Authorization For Expenditure (AFE). This report describes the tasks performed, the results, and conclusions for the first phase (Phase I) of the cooperative agreement.

  18. Modeling and Interpreting CHAMP Magnetic Anomaly Field over China Continent Using Spherical Cap Harmonic Analysis

    Institute of Scientific and Technical Information of China (English)

    Fu Yuanyuan; Liu Qingsheng; Yang Tao

    2004-01-01

    Based on the CHAMP Magsat data set, spherical cap harmonic analysis was used to model the magnetic fields over China continent. The data set used in the analysis includes the 15′×15′ gridded values of the CHAMP anomaly fields (latitude φ=25°N to 50°N and longitude λ=78°E to 135°E). The pole of the cap is located at φ=35°N and λ=110°E with half-angle of 30°. The maximum index (Kmax) of the model is 30 and the total number of model coefficients is 961, which corresponds to the minimum wavelength at the earth's surface about 400 km. The root mean square (RMS) deviations between the calculated and observed values are ~ 4 nT for ΔX, ~ 3 nT for ΔY and ~ 3.5 nT for ΔZ, respectively. Results show that positive anomalies are found mainly at the Tarim basin with ~6- 8 nT, the Yangtze platform and North China platform with ~4 nT, and the Songliao basin with ~4-6 nT. In contrast, negative anomaly is mainly located in the Tibet orogenic belt with the amplitude ~ (-6)-(-8) nT. Upward continuation of magnetic anomalies was used to semi-quantitatively separate the magnetic anomalies in different depths of crust. The magnetic anomalies at the earth's surface are from -6 to 10 nT for upper crust, middle crust -27 to 42 nT and lower crust -12 to 18 nT, respectively. The strikes of the magnetic anomalies for the upper crust are consistent with those for the middle crust, but not for the lower crust. The high positive magnetic anomalies mainly result from the old continental nucleus and diastrophic block (e.g. middle Sichuan continental nucleus, middle Tarim basin continental nucleus, Junggar diastrophic block and Qaidam diastrophic block). The amplitudes of the magnetic anomalies of the old continental nucleus and diastrophic block are related to evolution of deep crust. These results improve our understanding of the crustal structure over China continent.

  19. Coexistence of pumice and manganese nodule fields-evidence for submarine silicic volcanism in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Sudhakar, M.

    -generation mine-sites of manganese nodules, of high abundance and paramarginal ore grade, seem to be closely related to the pumice field. Circumstantial evidence, i.e. juxtaposed pumice and nodule fields in the vicinity of three major fracture zones (73 degrees E...

  20. Corrigendum to "Wind as the primary driver of erosion in the Qaidam Basin, China" [Earth Planet. Sci. Lett. 374 (2013) 1-10

    Science.gov (United States)

    Rohrmann, Alexander; Heermance, Richard; Kapp, Paul; Cai, Fulong

    2015-12-01

    The authors regret that the longitude coordinates are incorrect for some of the samples displayed in Table 1 (they are correct in Fig. 2). The corrected Table 1 appears below for the reader's convenience.

  1. Fluvial fan evolution during Late Quaternary climate changes: field and chronological constraints from the Indo-Gangetic basin

    Science.gov (United States)

    Singh, A.; Gupta, S.; Sinha, R.; Densmore, A.; Thomsen, K. J.; Nayak, N.; Joshi, S. K.; van Dijk, W. M.; Buylaert, J. P.; Mondal, S.; Kumar, D.; Mason, P. J.; Murray, A. S.; Kumar, M.; Shekhar, S.; Rai, S. P.

    2015-12-01

    The stratigraphic evolution of fluvial fans is to a large extent governed by channel avulsion. Spatial variations in alluvial architecture are influenced by avulsion magnitude and frequency. However due to the absence of long-term chronostratigraphic records of fan stratigraphy, it has proved difficult to test patterns of fan evolution against records of climate variability. In order to understand the processes of channel avulsion during fan evolution, it is important to determine the spatio-temporal pattern of fluvial channel aggradation, incision, and migration. In this study, we reconstruct the shallow sub-surface alluvial stratigraphy of fluvial fan systems formed by the major Himalayan rivers, the Sutlej and Yamuna, in the northwestern Indo-Gangetic basin. We map the spatial distribution of channel sand bodies deposited by these rivers and develop a chronostratigraphic model for the fluvial succession in a depositional dip perpendicular transect. Sediment cores up to ~50 m deep along two transects are used to reconstruct the shallow stratigraphy of the fan systems. Discontinuous channel sand bodies are separated by floodplain fines which occasionally show weak pedogenesis that mark the end of episodes of channel aggradation. Optically stimulated luminescence (OSL) dating is used to bracket the timing of channel-filling episodes, and their spatial distribution. Mapping of sand bodies coupled with chronostratigraphic constraints allows reconstruction of channel migration patterns and their timing across the Sutlej-Yamuna fans. Chronostratigraphy permits temporal correlation with published measures of monsoon variability. We find that fluvial aggradation at the western end of studied transects, near the middle of the Sutlej fan, terminated around ~20 ka. We also show that abandonment of the paleo-Sutlej and major fan-scale avulsion occurred after ~15 ka, and was followed by formation of incised valleys that confined the modern fluvial system in northwestern Indo

  2. Inversion of TEM data and analysis of the 2D induced magnetic field applied to the aquifers characterization in the Paraná basin, Brazil

    Science.gov (United States)

    Realpe Campaña, Julian David; Porsani, Jorge Luís; Bortolozo, Cassiano Antonio; Serejo de Oliveira, Gabriela; Monteiro dos Santos, Fernando Acácio

    2017-03-01

    Results of a TEM profile by using the fixed-loop array and an analysis of the induced magnetic field are presented in this work performed in the northwest region of São Paulo State, Brazil, Paraná Basin. The objectives of this research were to map the sedimentary and crystalline aquifers in the area and analyzing the behavior of the magnetic field by observation of magnetic profiles. TEM measurements in the three spatial components were taken to create magnetic profiles of the induced (secondary) magnetic field. The TEM data were acquired using a fixed transmitter loop of 200 m × 200 m and a 3D coil receiver moving along a profile line of 1000 m. Magnetic profiles of dBz, dBx and dBy components showed symmetrical spatial behavior related with loop geometry. z-component showed a behavior probably related to superparamagnetic effect (SPM). dBz data was used to perform individual 1D inversion for each position and to generate an interpolated pseudo-2D geoelectric profile. The results showed two low resistivity zones: the first shallow, between 10 m and 70 m deep, probably related to the Adamantina Formation (sedimentary aquifer). The second between 200 m and 300 m depth, probably related to a fractured zone filled with water or clay inside the basalt layer of the Serra Geral Formation (crystalline aquifer). These results agree with the well logs information available in the studied region.

  3. Avian diversity and feeding guilds in a secondary forest, an oil palm plantation and a paddy field in riparian areas of the kerian river basin, perak, malaysia.

    Science.gov (United States)

    Azman, Nur Munira; Latip, Nurul Salmi Abdul; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md; Shafie, Nur Juliani; Khairuddin, Nurul Liyana

    2011-12-01

    The diversity and the feeding guilds of birds in three different habitats (secondary forest, oil palm plantation and paddy field) were investigated in riparian areas of the Kerian River Basin (KRB), Perak, Malaysia. Point-count observation and mist-netting methods were used to determine bird diversity and abundance. A total of 132 species of birds from 46 families were recorded in the 3 habitats. Species diversity, measured by Shannon's diversity index, was 3.561, 3.183 and 1.042 in the secondary forest, the paddy field and the oil palm plantation, respectively. The vegetation diversity and the habitat structure were important determinants of the number of bird species occurring in an area. The relative abundance of the insectivore, insectivore-frugivore and frugivore guilds was greater in the forest than in the monoculture plantation. In contrast, the relative abundance of the carnivore, granivore and omnivore guilds was higher in the plantation. The results of the study show that the conversion of forest to either oil palm plantation or paddy fields produced a decline in bird diversity and changes in the distribution of bird feeding guilds.

  4. Using Cable Suspended Submersible Pumps to Reduce Production Costs to Increase Ultimate Recovery in the Red Mountain Field of the San Juan Basin Region

    Energy Technology Data Exchange (ETDEWEB)

    Don L. Hanosh

    2006-08-15

    A joint venture between Enerdyne LLC, a small independent oil and gas producer, and Pumping Solutions Inc., developer of a low volume electric submersible pump, suspended from a cable, both based in Albuquerque, New Mexico, has re-established marginal oil production from Red Mountain Oil Field, located in the San Juan Basin, New Mexico by working over 17 existing wells, installing cable suspended submersible pumps ( Phase I ) and operating the oil field for approximately one year ( Phase II ). Upon the completion of Phases I and II ( Budget Period I ), Enerdyne LLC commenced work on Phase III which required additional drilling in an attempt to improve field economics ( Budget Period II ). The project was funded through a cooperative 50% cost sharing agreement between Enerdyne LLC and the National Energy Technology Laboratory (NETL), United States Department of Energy, executed on April 16, 2003. The total estimated cost for the two Budget Periods, of the Agreement, was $1,205,008.00 as detailed in Phase I, II & III Authorization for Expenditures (AFE). This report describes tasks performed and results experienced by Enerdyne LLC during the three phases of the cooperative agreement.

  5. The controlling factors of oil and gas charging and accumulation of Puguang gas field in the Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Combined with oil and gas transport and accumulation, structure-Iithology evolution history, and with geochemistry and synthesizing geology methods, this paper studies the oil and gas discharge history of Puguang large scale gas field and the main controlling factors of oil accumulation. The natural gas in Puguang gas field is mainly coal-derived gas and oil-racked gas. The main hydrocarbon is Upper Permian coal mudstone and Lower Silurian mud shale with organic material. Puguang gas field has gone through discharge and adjustment 3 times, and it has favorable palaeostructure location, high quality dredge and effectively conserving conditions.

  6. Field detection of eastern equine encephalitis virus in the Amazon Basin region of Peru using reverse transcription-polymerase chain reaction adapted for field identification of arthropod-borne pathogens.

    Science.gov (United States)

    O'Guinn, Monica L; Lee, John S; Kondig, John P; Fernandez, Roberto; Carbajal, Faustino

    2004-02-01

    In support of efforts to develop rapid diagnostic assays for use in the field, reverse transcription-polymerase chain reaction (RT-PCR) assays were developed to detect arboviruses circulating in the Amazon Basin region of Peru. Previous knowledge of arthropod/pathogen relationships allowed a focused evaluation to be conducted in November 2000 that assessed the feasibility and reliability of a mobile, rapid, field-expedient RT-PCR diagnostic system aimed at detecting eastern equine encephalitis virus (EEEV) in Culex (Melanoconion) pedroi mosquitoes. Modifications were made to a commercially available mobile molecular laboratory kit and assay procedures were tailored for use under harsh environmental conditions with field-collected and field-processed mosquitoes. From CO2 baited mosquito light traps, 3,227 Cx. (Mel.) pedroi mosquitoes were collected and sorted into 117 pools. The pools were processed and assayed in the field by RT-PCR and five of those pools were found positive for EEEV. Laboratory sequence analysis confirmed the presence of two distinct subtypes of EEEV.

  7. Petrography and diagenesis of Gomo member sandstones - Candeias Formation (lower cretaceous) Rio do Buoil field, Reconcavo Basin; Petrografia e diagenese dos arenitos do Membro Gomo - Formacao Candeias (Cretaceo Inferior) no Campo de Rio do Bu, Bacia do Reconcavo

    Energy Technology Data Exchange (ETDEWEB)

    Mato, Luiz F.; Souza, Edson M. [PETROBRAS, BA (Brazil). Distrito de Exploracao

    1988-04-01

    Characteristics, textural and compositional aspects, analyse the provenance and diagenetic evolution of the Gomo Member/Candeias Formation sandstones (Lower Cretaceous) in the Rio do Bu oil field, Reconcavo Basin, are discussed. Studies of sandstone petrography, shales and carbonates associated, diagenetic sequence, rifts fractures and cementation characterization, are also analyzed. 17 figs., 2 tabs., 19 refs

  8. Bransfield Basin and Cordilleran Orogenesis

    Science.gov (United States)

    Dalziel, I. W.; Austin, J. A.; Barker, D. H.; Christensen, G. L.

    2003-12-01

    Tectonic uplift of the Andean Cordillera was initiated in the mid-Cretaceous with inversion of a composite marginal basin along 7500 km of the continental margin of South America, from Peru to Tierra del Fuego and the North Scotia Ridge. In the southernmost Andes, from 50-56 degrees S, the quasi-oceanic floor of this basin is preserved in the obducted ophiolitic rocks of the Rocas Verdes (Green Rocks) basin. We suggest that the basin beneath Bransfield Strait, 61-64 degrees S, separating the South Shetland Islands from the Antarctic Peninsula, constitutes a modern analog for the Rocas Verdes basin. Marine geophysical studies of Bransfield basin have been undertaken over the past 12 years by the Institute for Geophysics, University of Texas at Austin, under the auspices of the Ocean Sciences Division and United States Antarctic Program, National Science Foundation. These studies have elucidated the structure and evolution of Bransfield basin for comparison with the Rocas Verdes basin, with a view to eventual forward modeling of the evolution of a hypothetical cordilleran orogen by compression and inversion of the basin. These are the processes that can be observed in the tectonic transformation of the Rocas Verdes basin into the southernmost Andean cordillera, as South America moved rapidly westward in an Atlantic-Indian ocean hot-spot reference frame during the mid-Cretaceous. Multi-channel reflection seismic data from the Bransfield basin reveal an asymmetric structural architecture characterized by steeply-dipping normal faults flanking the South Shetlands island arc and gently dipping listric normal faults along the Antarctic Peninsula margin. Normal fault polarity reversals appear to be related to distributed loci of magmatic activity within the basin. This architecture is remarkably similar to that deduced from field structural studies of the Rocas Verdes basin. Notably, the oceanward-dipping, low angle normal faults along the Antarctic Peninsula margin

  9. Investigating the Subsurface Stress Field based on Hybrid Earthquake Focal Mechanisms: Examples from the Fort Worth Basin, Texas

    Science.gov (United States)

    Jia, S.; Eaton, D. W. S.; Wong, R.

    2016-12-01

    Knowledge of in situ stress state and rock failure mechanisms is key for modelling and predicting subsurface material behavior. Earthquake focal mechanisms are extensively used for in situ stress determination, as reflected by their widespread use for the World Stress Map project. The rupture process emits radiated seismic energy, from which equivalent force couples acting a point (moment tensor) may be determined. Inversion methods, including formal estimates of uncertainty, have been developed to estimate stress parameters from moment-tensor observations. Methods that have been developed so far are based on the assumptions that the source mechanism is purely double-couple (DC) and the direction of the slip vector is parallel to the shear stress acting on the fault plane (Wallace-Bott hypothesis). However, this is not always the case, especially for microseismic events that occur during hydraulic fracturing, in which case injected fluids can significantly elevate the pore pressure. In the case of shear-tensile failure, the slip vector may deviate from the fault plane due to complex failure mechanisms surrounding an injection site. To eliminate this restriction and better analyze stress state during injection, a new approach is developed under the assumption that the slip vector is parallel to the direction of the traction vector acting on a fault plane. The microseismic data analyzed in this study were acquired in 2010 during a multi-well completion in the Fort Worth Basin. The dataset contains 7444 microseismic events with full moment-tensor solutions. Results of our analysis, which utilizes events with the best resolved solutions, reveal that the shear-tensile stress inversion approach improves the determination of failure plane and stress state.

  10. The Gela Basin pockmark field in the strait of Sicily (Mediterranean Sea: chemosymbiotic faunal and carbonate signatures of postglacial to modern cold seepage

    Directory of Open Access Journals (Sweden)

    M. Taviani

    2013-07-01

    Full Text Available The geo-biological exploration of a pockmark field located at ca. 800 m below sea level in the Gela basin (Strait of Sicily, Central Mediterranean provided a relatively diverse chemosymbiotic community and methane-imprinted carbonates. To date, this is the first occurrence of such a type of specialised deep-water cold-seep communities recorded from this key region, before documented in the Mediterranean as rather disjunct findings in its eastern and westernmost basins. The thiotrophic chemosymbiotic organisms recovered from this area include empty tubes of the vestimentiferan Lamellibrachia sp., loose and articulated shells of lucinids (Lucinoma kazani, Myrtea amorpha, vesicomyids (Isorropodon perplexum, and gastropods (Taranis moerchii. A callianassid decapod (Calliax sp. was consistently found alive in large numbers in the pockmark mud. Their post-mortem calcified parts mixed with molluscs and subordinately miliolid foraminifers form a distinct type of skeletal assemblage. Carbonate concretions display δ13C values as low as −40‰ PDB suggesting the occurrence of light hydrocarbons in the seeping fluids. Since none of the truly chemosymbiotic organisms was found alive, although their skeletal parts appear at times very fresh, some specimens have been AMS-14C dated to shed light on the historical evolution of this site. Lamellibrachiav and Lucinoma are two of the most significant chemosymbiotic taxa reported from various Mediterranean cold seep sites (Alboran Sea and Eastern basin. Specimens from station MEDCOR78 (pockmark #1, Lat. 36°46´10.18" N, Long. 14°01´31.59" E, 815 m below sea level provided ages of 11736 ± 636 yr cal BP (Lamellibrachia sp., and 9609.5 ± 153.5 yr cal BP (L. kazani. One shell of M. amorpha in core MEDCOR81 (pockmark #6, Lat 36°45´38.89" N, Long 14°00´07.58" E, 822 m below sea level provided a sub-modern age of 484 ± 54 yr cal BP. These ages document that fluid seepage at this pockmark site has been

  11. Mechanism for calcite dissolution and its contribution to development of reservoir porosity and permeability in the Kela 2 gas field, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    YU BingSong; DONG HaiLiang; RUAN Zhuang

    2008-01-01

    This study is undertaken to understand how calcite precipitation and dissolution contributes to depth-related changes in porosity and permeability of gas-bearing sandstone reservoirs in the Kela 2 gas field of the Tarim Basin, Northwestern China. Sandstone samples and pore water samples are collected from well KL201 in the Tarim Basin. Vertical profiles of porosity, permeability, pore water chemistry, and the relative volume abundance of calcite/dolomite are constructed from 3600 to 4000 m below the ground surface within major oil and gas reservoir rocks. Porosity and permeability values are inversely correlated with the calcite abundance, indicating that calcite dissolution and precipitation may be controlling porosity and permeability of the reservoir rocks. Pore water chemistry exhibits a systematic variation from the Na2SO4 type at the shallow depth (3600-3630 m), to the NaHCO3 type at the intermediate depth (3630-3695 m), and to the CaCl2 type at the greater depth (3728-3938 m). The geochemical factors that control the calcite solubility include pH, temperature, pressure, Ca2+ concentration, the total inorganic carbon concentration (∑CO2), and the type of pore water. Thermodynamic phase equilibrium and mass conservation laws are applied to calculate the calcite saturation state as a function of a few key parameters. The model calculation illustrates that the calcite solubility is strongly dependent on the chemical composition of pore water, mainly the concentration difference between the total dissolved inorganic carbon and dissolved calcium concentration (i.e., [ΣCO2]-[Ca2+]). In the Na2SO4 water at the shallow depth, this index is close to 0, pore water is near the calcite solubility. Calcite does not dissolve or precipitate in significant quantities. In the NaHCO3 water at the intermediate depth, this index is greater than 0, and pore water is supersaturated with respect to calcite. Massive calcite precipitation was observed at this depth interval and

  12. Application of high-precision 3D seismic technology to shale gas exploration: A case study of the large Jiaoshiba shale gas field in the Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Zuqing Chen

    2016-03-01

    Full Text Available The accumulation pattern of the marine shale gas in South China is different from that in North America. The former has generally thin reservoirs and complex preservation conditions, so it is difficult to make a fine description of the structural features of shale formations and to reflect accurately the distribution pattern of high-quality shale by using the conventional 2D and 3D seismic exploration technology, which has an adverse effect on the successful deployment of horizontal wells. In view of this, high-precision 3D seismic prospecting focusing on lithological survey was implemented to make an accurate description of the distribution of shale gas sweet spots so that commercial shale gas production can be obtained. Therefore, due to the complex seismic geological condition of Jiaoshiba area in Fuling, SE Sichuan Basin, the observation system of high-precision 3D seismic acquisition should have such features as wide-azimuth angles, small trace intervals, high folds, uniform vertical and horizontal coverage and long spread to meet the needs of the shale gas exploration in terms of structural interpretation, lithological interpretation and fracture prediction. Based on this idea, the first implemented high-precision 3D seismic exploration project in Jiaoshiba area played an important role in the discovery of the large Jiaoshiba shale gas field. Considering that the high-quality marine shale in the Sichuan Basin shows the characteristics of multi-layer development from the Silurian system to the Cambrian system, the strategy of shale gas stereoscopic exploration should be implemented to fully obtain the oil and gas information of the shallow, medium and deep strata from the high-precision 3D seismic data, and ultimately to expand the prospecting achievements in an all-round way to balance the high upstream exploration cost, and to continue to push the efficient shale gas exploration and development process in China.

  13. Characteristics of Sr, Nd and Pb isotopic compositions of hydrothermal Si-Fe-Mn-oxyhydroxides at the PACMANUS hydrothermal field, Eastern Manus Basin

    Institute of Scientific and Technical Information of China (English)

    YANG Baoju; ZENG Zhigang; WANG Xiaoyuan

    2015-01-01

    Si-Fe-Mn-oxyhydroxides dredged at the PACMANUS (Papua New Guinea–Australia–Canada–Manus) hydrothermal field, Eastern Manus Basin, have87Sr/86Sr=0.708 079–0.708 581;εNd=5.149 833–6.534 826;208Pb/204Pb=38.245–38.440;207Pb/204Pb=15.503–15.560;206Pb/204Pb=18.682–18.783.87Sr/86Sr isotope ratios are relatively homogeneous and close to the value of the surrounding seawater (0.709 16). The content of Sr in the samples contributed by seawater was estimated to be 76.7%–83.1% of total amount. The mixing temperature of hydrothermal fluids and seawater were ranging from 53.2°C to 72.2°C and the hydrothermal activities were unstable when the samples precipitated. TheεNd values of all the samples are positive, which differ from the values of ferromanganese nodules (crusts) with hydrogenic origin. Nd was mainly derived from substrate rocks leached by hydrothermal circulation and preserved the hydrothermal signature. Pb isotopic compositions of most samples show minor variability except Sample #9–2 that has relatively high values of Pb isotopes. The Pb may be derived from the Eastern Manus Basin rocks leached by the hydrothermal fluid. The slightly lower208Pb/204Pb and 207Pb/204Pb values of the samples indicated that the hydrothermal circulation in PACMANUS was not entire and sufficient, or that hydrothermal circulation had transient changes in the past. Si-Fe-Mn-oxyhydroxides in the samples preserved the heterogeneities of local rocks.

  14. 2007 Rocky Mountain Section Friends of the Pleistocene Field Trip - Quaternary Geology of the San Luis Basin of Colorado and New Mexico, September 7-9, 2007

    Science.gov (United States)

    Machette, Michael N.; Coates, Mary-Margaret; Johnson, Margo L.

    2007-01-01

    Prologue Welcome to the 2007 Rocky Mountain Cell Friends of the Pleistocene Field Trip, which will concentrate on the Quaternary geology of the San Luis Basin of Colorado and New Mexico. To our best knowledge, Friends of the Pleistocene (FOP) has never run a trip through the San Luis Basin, although former trips in the region reviewed the 'Northern Rio Grande rift' in 1987 and the 'Landscape History and Processes on the Pajarito Plateau' in 1996. After nearly a decade, the FOP has returned to the Rio Grande rift, but to an area that has rarely hosted a trip with a Quaternary focus. The objective of FOP trips is to review - in the field - new and exciting research on Quaternary geoscience, typically research being conducted by graduate students. In our case, the research is more topically oriented around three areas of the San Luis Basin, and it is being conducted by a wide range of Federal, State, academic, and consulting geologists. This year's trip is ambitious?we will spend our first day mainly on the Holocene record around Great Sand Dunes National Park and Preserve, the second day on the Quaternary stratigraphy around the San Luis Hills, including evidence for Lake Alamosa and the 1.0 Ma Mesita volcano, and wrap up the trip's third day in the Costilla Plain and Sunshine Valley reviewing alluvial stratigraphy, the history of the Rio Grande, and evidence for young movement on the Sangre de Cristo fault zone. In the tradition of FOP trips, we will be camping along the field trip route for this meeting. On the night before our trip, we will be at the Great Sand Dunes National Park and Preserve's Pinyon Flats Campground, a group facility located about 2 miles north of the Visitors Center. After the first day's trip, we will dine and camp in the Bachus pit, about 3 miles southwest of Alamosa. For the final night (after day 2), we will bed down at La Junta Campground at the Bureau of Land Management (BLM) Wild and Scenic Rivers State Recreation Area, west of Questa

  15. Increased oil production and reserves from improved completion techniques in the Bluebell Field, Uinta Basin, Utah. Fourth quarterly technical progress report, July 1, 1994--september 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, C.D.

    1994-12-31

    Bluebell field ill tile Uinta Basin, Utah, is a rich petroleum reserve. The field has produced over 125 million barrels of oil from the lacustrine rocks of the Green River Formation. Standard completion techniques, which consist of perforating up to thousands of feet of section at one time, have resulted in opening thief, water-producing and non-productive zones. Low recoverabilitv is largely due to the lack of understanding of the relationship between heterolithic facies, reservoir fracture systems and clay migration. These areas were investigated by analyzing over 1,500 feet of core from the Bluebell area. Approximately 60% of the core consists of carbonates and 40% consists of clastics (predominantly sandstones). The carbonate rocks in general have good porosity and randomly oriented, interconnected macrofractures, whereas the macrofractures in the sandstones are more vertical and isolated. The sandstones however, do have the best reservoir capacity due to inherent interparticle porosity. Some shales display overpressured hydro-microfractures. Preliminary analysis of clay types indicates swelling illite-smectite mixed layer clays as well as kaolinite in both the clastic and carbonate rocks. These swelling, clay types combine with the high pour point waxy oils to reduce production efficiency and total recovery.

  16. 15/9 Gamma gas field offshore Norway, new trap type for North Sea basin with regional structural implications

    Energy Technology Data Exchange (ETDEWEB)

    Pegrum, R.M.; Ljones, T.E.

    1984-07-01

    The 15/9 Gamma gas field lies in the central North Sea midway between Norway and the United Kingdom. The field was discovered in 1981 and, by mid-1982, 3 additional confirmation wells had been completed. The reservoir is provided by a complex of Paleocene submarine-fan sandstones. The sandstones decrease in thickness across the field from 150 m (492 ft) in the northwest to less than 50 m (164 ft) in the southeast. The sandstones pinch out entirely a few kilometers beyond the field. The volume of gas in place is on the order of 65 X 10/sup 9/ m/sup 3/ (2.3 tcf). The trap in the Paleocene sandstones is interpreted as being formed by a mid-Tertiary compressive phase which reactivated preexisting basement faults. Detailed structural analysis suggests that WNW-ESE-trending faults have suffered repeated strike-slip offset associated with Jurassic transtension and mid-Cretaceous and middle Tertiary transpression. The writers suggest that the WNW-ESEtrending basement faults represent a northwestward continuation of the Tornquist line, a fundamental fracture zone bounding the East European-Scandinavian platform, which had previously been considered as terminating at the line of the Oslo graben, about 250 km (155 mi) to the southeast.

  17. Recency of Faulting and Neotechtonic Framework in the Dixie Valley Geothermal Field and Other Geothermal Fields of the Basin and Range

    Energy Technology Data Exchange (ETDEWEB)

    Steven Wesnousky; S. John Caskey; John W. Bell

    2003-02-20

    We studied the role that earthquake faults play in redistributing stresses within in the earths crust near geothermal fields. The geographic foci of our study were the sites of geothermal plants in Dixie Valley, Beowawe, and Bradys Hot Springs, Nevada. Our initial results show that the past history of earthquakes has redistributed stresses at these 3 sites in a manner to open and maintain fluid pathways critical for geothermal development. The approach developed here during our pilot study provides an inexpensive approach to (1) better define the best locations to site geothermal wells within known geothermal fields and (2) to define the location of yet discovered geothermal fields which are not manifest at the surface by active geothermal springs. More specifically, our investigation shows that induced stress concentrations at the endpoints of normal fault ruptures appear to promote favorable conditions for hydrothermal activity in two ways. We conclude that an understanding of the spatial distribution of active faults and the past history of earthquakes on those faults be incorporated as a standard tool in geothermal exploration and in the siting of future boreholes in existing geothermal fields.

  18. Characteristics and simulation of the canopy conductance of Hippophae rhamnoides in Qaidam Region of northwestern China%柴达木地区沙棘冠层导度特征及模拟

    Institute of Scientific and Technical Information of China (English)

    王辉; 贺康宁; 徐特; 刘玉娟; 刘颖; 张雪

    2015-01-01

    为了揭示沙棘冠层导度对环境因子的响应规律,评价Jarvis模型在沙棘冠层尺度上的适用性,利用Granier热消散式探针连续测定了青海省柴达木盆地实验站内的沙棘灌丛树干液流,并同步观测气象因子,利用 Penman-Monteith方程反推方法,获得了长期连续的冠层导度。在分析沙棘冠层导度动态变化规律的基础上,采用十字交叉法对Jarvis模型进行参数率定和误差分析。结果表明:研究区沙棘冠层导度日变化呈“单峰型”曲线,冠层导度随饱和水汽压差的增加呈负指数关系下降,并与太阳辐射强度呈正相关。基于饱和水汽压差、太阳辐射强度和气温这3个环境变量的Jarvis模型可解释gc变化的81%,且最低相对误差仅11.01%。环境因子对冠层导度( gc )模型精度的影响依次为饱和水汽压差(ⅤPD)>太阳辐射强度( Rs )>气温( T)。%The aim of this study was to explain the response of canopy conductance of sea buckthorn ( Hippophae rhamnoides ) to different environmental conditions so as to evaluate the feasibility of application of Jarvis model in sea buckthorn at the canopy scale. By using Granier’ s thermal dissipation probe, the sap flow of sea buckthorn in Qaidam Basin in Qinghai Province, northwestern China was continuously measured,and as well,the environmental factors such as incoming solar radiation intensity (Rs), air temperature (T), relative humidity (RH), wind speed (u) and rainfall were synchronically measured. Based on sap flow, canopy conductance ( gc ) was continuously simulated by back-calculated Penman-Monteith model. By analysis of gc of sea buckthorn, Jarvis stomatal model was simulated and analyzed with cross-validation. The results indicated that the diurnal variation in canopy conductance of sea buckthorn showed a single-peaked curve. There was a negative logarithm relationship between canopy conductance and vapor pressure deficit (ⅤPD ) under

  19. Source Rocks for the Giant Puguang Gas Field, Sichuan Basin: Implication for Petroleum Exploration in Marine Sequences in South China

    Institute of Scientific and Technical Information of China (English)

    ZOU Huayao; HAO Fang; ZHU Yangming; GUO Tonglou; CAI Xunyu; LI Pingping; ZHANG Xuefeng

    2008-01-01

    Detailed geochemistry studies were conducted to investigate the origin of solid bitumens and hydrocarbon gases in the giant Puguang gas field. Two types of solid bitumens were recognized: low sulfur content, low reflectance (LSLR) solid bitumens in sandstone reservoirs in the Xujiahe Formation and high sulfur content, high reflectance (HSHR) solid bitumens in the carbonate reservoirs in the Lower Triassic Feixianguan and Upper Permian Changxing formations. Solid bitumens in the Upper Triassic Xujiahe Formation correlate well with extracts from the Upper Triassic to Jurassic nonmarine source rocks in isotopic composition of the saturated and aromatic fractions and biomarker distribution. Solid bitumens in the Feixianguan and Changxing formations are distinctly different from extracts from the Cambrian and Silurian rocks but display reasonable correlation with extracts from the Upper Permian source rocks both in isotopic composition of the saturated and aromatic fractions and in biomarker distribution, suggesting that the Permian especially the Upper Permian Longtan Formation was the main source of solid bitumens in the carbonate reservoirs in the Feixianguan and Changxing formations in the Puguang gas field. Chemical and isotopic composition of natural gases indicates that the majority of hydrocarbon gases originated from sapropelic organic matter and was the products of thermal cracking of accumulated oils. This study indicates that source rock dominated by sapropelic organic matter existed in the Upper Permian and had made major contribution to the giant Puguang gas field, which has important implication for petroleum exploration in marine sequences in South China.

  20. Field screening of water, soil, bottom sediment, and biota associated with irrigation drainage in the Dolores Project and the Macos River basin, southwestern Colorado, 1994

    Science.gov (United States)

    Butler, D.L.; Osmundson, B.C.; Krueger, R.P.

    1997-01-01

    A reconnaissance investigation for the National Irrigation Water Quality Program in 1990 indicated elevated selenium concentrations in some water and biota samples collected in the Dolores Project in southwestern Colorado. High selenium concentrations also were indicated in bird samples collected in the Mancos Project in 1989. In 1994, field screenings were done in parts of the Dolores Project and Mancos River Basin to collect additional selenium data associated with irrigation inthose areas. Selenium is mobilized from soils in newly irrigated areas of the Dolores Project called the Dove Creek area, which includes newly (since 1987) irrigated land north of Cortez and south of Dove Creek.Selenium was detected in 18 of 20stream samples, and the maximum concentration was 12micrograms per liter. The Dove Creek area is unique compared to other study areas of the National Irrigation Water Quality Program becauseselenium concentrations probably are indicative of initial leaching conditions in a newly irrigated area.Selenium concentrations in nine shallow soil samples from the Dove Creek area ranged from 0.13 to 0.20 micrograms per gram. Selenium concentrations in bottom sediment from six ponds were less than the level of concern for fish and wildlife of 4 micrograms per gram. Many biota samples collected in the Dove Creek area had elevated selenium concentrations when compared to various guidelines and effect levels,although selenium concentrations in water, soil, and bottom sediment were relatively low. Selenium concentrations in 12 of 14 aquatic-invertebratesamples from ponds exceeded 3 micrograms per gram dry weight, a dietary guideline for protection of fish and wildlife. The mean seleniumconcentration of 10.3 micrograms per gram dry weight in aquatic bird eggs exceeded the guideline for reduced hatchability of 8 micrograms per gramdry weight. Two ponds in the Dove Creek area had a high selenium hazard rating based on a new protocol for assessing selenium hazard in

  1. Identifying Seismic Risk in the Appalachian Basin Geothermal Play Fairway Analysis Project Using Potential Fields, Seismicity, and the World Stress Map

    Science.gov (United States)

    Horowitz, F. G.

    2015-12-01

    A collaborative effort between Cornell University, Southern Methodist University, and West Virginia University has been sponsored by the US Department Of Energy to perform a Geothermal Play Fairway Analysis of the low temperature direct use potential for portions of the Appalachian sedimentary basin in New York, Pennsylvania and West Virginia - abbreviated here as GPFA-AB. One risk factor - of several being analyzed for the GPFA-AB - is whether a candidate location is near an active fault, and thereby potentially susceptible to induced seismicity from geothermal operations. Existing fault maps do not share the GPFA-AB boundaries or scale. Hence, their use leads to problems of uneven coverage, varying interpretation of faults vs. lineaments, and different mapping scales. For more uniformity across the GPFA-AB region, we use an analysis of gravity and magnetic fields. Multiscale edge Poisson wavelet analyses of potential fields ("worms") have a physical interpretation as the locations of lateral boundaries in a source distribution that exactly generates the observed field. Not all worms are faults, and of faults, only a subset might be active. Also, worms are only sensitive to steeply dipping structures. To identify some active structures, we plot worms and intra-plate earthquakes from the ISC, NEIC, and EarthScope TA catalogs. Worms within a small distance of epicenters are tracked spatially. To within errors in location, this is a sufficient condition to identify structures that might be active faults - which we categorize with higher risk than other structures. Plotting worms within World Stress Map σ1 directions yields an alternative approach to identifying activatable structures. Here, we use worms to identify structures with strikes favorably oriented for failure by Byerlee's law. While this is a necessary criterion for fault activation it is not a sufficient one - because we lack detailed information about stress magnitudes throughout the GPFA-AB region

  2. Integration of seismic interpretation and petrophysical studies on Hawaz Formation in J-field NC-186 concession, Northwest Murzuq basin, Libya

    Science.gov (United States)

    Mohamed, A. K.; Selim, E. I.; Kashlaf, A.

    2016-12-01

    This study has been carried out by the integration of seismic interpretations and the well-logging analysis of ten wells distributed in J-field of concession NC-186, Murzuq basin, Libya. Twenty (3D) seismic lines and ten wells have been analyzed. The results of this study indicated that, the main reservoir in this concession is Hawaz Formation. Hawaz has been split into 8 units with a subdivision of Hawaz H4 into three subunits with the objective of better characterization of the three general fine upward intervals. The lower interval of H4 zone presents the better reservoir properties. The depth of reflector H4 ranges from 4100 ft in the northwestern part of the study area and increases to 4600 ft in the southeastern part of the study area. In this study, the outline of the Hawaz paleohighs which is NC-186 Field "J" is generally trending in the NW-SE direction. The well logging analysis particularly quick look interpretation indicates that Hawaz Formation in the studied wells is mainly oil-bearing with some water-bearing sand levels at the horizons from H4 to and H6 which are potentially the main reservoirs. The water bearing zones are beyond these horizons starting from the sub-horizon H6c and the oil water contact is probably at depth 4495 ft. The crossplot of porosity-saturation for H5 and H6b indicates firmly that these horizons are indeed at irreducible state and will produce mainly oil as indicated in J4-NC186 well, while the crossplot of H8 shows wide scattering of points which is the main characteristic for water producing horizon. The depth of Hawaz Formation H4 is more than 4160 ft in J4, J12 and J16 wells in the northwestern parts of this field and increases to 4400 in the central part of the concession at well J1.

  3. Characteristics of carbonate gas pool and multistage gas pool formation history of Hetianhe gas field, Tarim Basin, Northwest China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Hetianhe is a big carbonate gas field which is found and demonstrated in the period of "Chinese National Ninth 5-Year Plan". The proved reserve of Hetianhe gas field is over 600×108 m3. Its main producing layers are Carboniferous bioclastic limestone and Ordovician carbonate composed of buried hill. The former is stratified gas pool with water around its side, and the latter is massive gas pool with water in its bottom. The gases in the gas pools belong to dry gases with normal temperature and pressure systems. Based on the correlation of gas and source rock, the gases are mainly generated from Cambrian source rocks. According to the researches on source rock and structure evolution, and the observations on the thin section to reservoir bitumen and the studies on homogenization temperature of fluid inclusions, the gas pool has been identified and divided into three formation periods. The first is Late Caledonian when the oil generated from the Cambrian source rocks and migrated along faults, as a form of liquid facies into Ordovician carbonate reservoir and accumulated there. After that, the crust uplifted, the oil reservoir had been destroyed. The second is Late Hercynian when condensate gases generated from the Cambrian source rocks and migrated into Ordovician reservoir, as a form of liquid facies. Since the fractures had reached P strata, so the trap might have a real poor preservation condition, and the large-scale gas pool formation had not happened. The third gas reservoir formation period occurred in Himalaya. The fractures on both sides of Hetianhe gas field developed violently under the forces of compression, and thus the present fault horst formed. The dry gases generated from Cambrian source rocks and migrated upwards as the form of gas facies into Ordovician and Carboniferous reservoirs, and the large gas pool as discovered at present was formed finally.

  4. Large-scale Tazhong Ordovician Reef-fiat Oil-Gas Field in the Tarim Basin of China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xinyuan; WANG Zhaoming; YANG Haijun; ZHANG Lijuan; HAN Jianfa; WANG Zhenyu

    2009-01-01

    The Tazhong reef-flat oil-gas field is the first large-scale Ordovician organic reef type oil-gas field found in China.Its organic reefs were developed in the early Late Ordovician Lianglitag Formation, and are the first large reefs of the coral-stromatoporoid hermatypic community found in China.The organic reefs and platform-margin grain banks constitute a reef-fiat complex, mainly consisting of biolithites and grainstones.The biolithites can be classified into the framestone, bafflestone.bindstone etc.The main body of the complex lies around the wells from Tazhong-24 to Tazhong-82, trending northwest, with the thickness from 100 to 300 m, length about 220 km and width 5-10 km.It is a reef-flat lithologic hydrocarbon reservoir, with a very complex hydrocarbon distribution:being a gas condensate reservoir as a whole with local oil reservoirs.The hydrocarbon distribution is controlled by the reef complex.generally located in the upper 100-200 m part of the complex,and largely in a banded shape along the complex.On the profile,the reservoir shows a stratified feature.with an altitude difierence of almost 2200 m from southeast to northwest.The petroleum accumulation is controlled by karst reservoir beds and the northeast strike-slip fault belt. The total geologic reserves had reached 297.667 Mt by 2007.

  5. Video-Based Electroshocking Platform to Identify Lamprey Ammocoete Habitats: Field Validation and New Discoveries in the Columbia River Basin

    Energy Technology Data Exchange (ETDEWEB)

    Arntzen, Evan V.; Mueller, Robert P.

    2017-05-04

    A deep water electroshocking platform (DEP), developed to characterize larval lampreys (ammocoetes) and associated habitat in depths up to 15 m, was recently tested in the field. The DEP samples 0.55 m2∙min-1 without requiring ammocoete transport to the surface. Searches were conducted at a known rearing location (mouth of the Wind River, WA) and at locations on the Cowlitz River, WA, where ammocoetes had not previously been found. At the mouth of the Wind River, video imaged ammocoetes ranged from 50 to 150 mm in water depths between 1.5 m and 4.5 m and were more common in sediments containing organic silt. Ammocoetes (n=137) were detected at 61% of locations sampled (summer) and 50% of the locations sampled (winter). Following the field verification, the DEP was used on the lower 11.7 km of the Cowlitz River, WA. Ammocoetes (n=41) were found with a detection rate of 26% at specific search locations. Cowlitz River sediment containing ammocoetes was also dominated by silt with organic material, often downstream of alluvial bars in water depths from 0.8 to 1.7 m. Test results indicated a high sampling efficiency, favorable detection rates, and little or no impact to ammocoetes and their surrounding benthic environments.

  6. Sedimentological evolution of the Givetian-Eifelian (F3) sand bar of the West Alrar field, Illizi Basin, Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Chaouchi, R. [National Institute for Hydrocarbons and Chemistry, Boumerdes (Algeria); Malla, M.S.; Kechou, F. [Sonatrach, Algiers (Algeria). Exploration Div.

    1998-12-31

    Commercial accumulations of hydrocarbons depend on several factors, among which sedimentological conditions are of prime importance. Such sedimentatological factors are of particular importance in controlling both entrapment and reservoir quality in the western part of the Alrar field, within the F3 sandstone reservoir of Givetian-Eifelian age. Recent well results have shown facies and reservoir quality distribution to be more complex and generally more favourable than previously predicted. A series of tidally influenced litoral bars are now believed to have existed in the Alrar area at the time of deposition of the reservoir, these being elongated in a NW-SE direction in the West Alrar area, with an interbar area in the vicinity of well DZ-1. The highest reservoir quality is largely confined to this bar facies and understanding its distribution is therefore vital to locating development wells. (author)

  7. Organic geochemistry of heavy/extra heavy oils from sidewall cores, Lower Lagunillas Member, Tia Juana Field, Maracaibo Basin, Venenzuela

    Energy Technology Data Exchange (ETDEWEB)

    Tocco, R.; Alberdi, M. [PDVSA-Inteveo S.A., Caracas (Venezuela)

    2002-10-01

    The study of 22 oils from sidewall cores taken at different depths in the Lower Lagunillas Member, well LSJ-AB, Tia Juana Field, Maracaibo Lake is presented, with the purpose of predicting the intervals that present the best crude oil quality. Differences were detected in the biodegradation levels of the studied samples, which are correlated with the depth at which the sidewall core was taken. The API gravity was considered for the oils from each sidewall core and it was found that toward the top of the sequence, the oils have an API gravity of 10.6-11.2{sup o}C, while toward the base part of the sequence, the well produces extra heavy oils with an API gravity that varies between 8.2 and 8.7{sup o}. 12 refs., 5 figs., 1 tab.

  8. Therm odynamics of Diagenetic Fluid and Fluid/Mineral Reactions in the Eogene Xingouzui Formation,Oil Field T,Jianghan Basin

    Institute of Scientific and Technical Information of China (English)

    倪师军; 罗扬棣; 等

    1994-01-01

    This study focuses on the thermodynamics of diagenetic fluid from the Eogene Xingouzui Forma-tion which represents the most important reservoir in Field Oil T in the Jianghan Basin.The meas-ured homegenizagion temperatures(110-139℃)of fluid inclusions in diagenetic minerals fall within the range of 67-155℃ at the middle diagenetic stage .The pressure of diagenetic fluid is estimated at 10.2-56 Mpa .The activity of ions in the fluid shows a tendency of Ca2+>Mg2+>Na+>K+>Fe3+>Fe2+ for cations, and HCO3->SO22->F->Cl->CO22- for anions. For the gaseous facies, there is a tendency of CO2>CO>H2S>CH4>H2. According to the thermodynamic calculations,the pH and Eh of the fluid are 5.86-6.47 and -0.73-0.64V, respectively. As a result of the interaction between such a diagenetic fluid and minerals in the sedi-ments,feldspars were dissolved or alterated by other minerals. The clay mineral kaolinite was instable and hence was replaced by illite and chloritoid.

  9. Characterization of low contrast shale-sand reservoir using Poisson impedance inversion: Case study of Gumai formation, Jambas field Jambi Sub-basin

    Science.gov (United States)

    Haris, A.; Nenggala, Y.; Suparno, S.; Raguwanti, R.; Riyanto, A.

    2017-07-01

    Low impedance contrast between the shale-sand layer, which can be found in the situation where shale layer wrapped in the sand reservoir, is a challenging case for explorationist in characterizing sand distribution from shale layer. In this paper, we present the implementation of Poisson impedance in mapping sand distribution in Gumai formation, Jambas Field, Jambi Sub-basin. Gumai formation has become a prospective zone, which contains sandstone with strong laterally change. The characteristic of facies at Gumai formation, which is laterally changing, has been properly mapped based on the Acoustic impedance (AI) and Shear impedance (SI). These two impedances, which is yielded by performing seismic simultaneous inversion, is then combined to generate Poisson impedance. The Poisson impedance is conceptually formulated as a contrast between AI and a scaled SI with the scale is estimated from the gradient of the relationship between AI and SI. Our experiment shows that the Poisson impedance map is able to separate the sand distribution from the shale layer. Therefore the sand facies has been clearly delineated from the contrast of Poisson impedance.

  10. Application of 'BIPI' tests employing natural and artificial tracers in water flooded oil fields of the Neuquina Basin (Argentine)

    Energy Technology Data Exchange (ETDEWEB)

    Somaruga, C. [Comahue Univ., Engineering Dept., Neuquen (Argentina); Gazzera, C.; Wouterlood, C. [Petrolera Perez Companc SA. Area Entre Lomas., Neuquen (Argentina)

    2001-07-01

    A methodology to determine the origin and distribution of bottom water in an oil producing well influenced by several injectors in waterflooding projects is presented. This methodology is complementary of inter-well tracer tests and salinity records analysis and was denominated BIPI (brief interruptions of producing-injecting wells) test. It requires the closing of a well (injector or producer) during a short time and its later re-opening. The original flow pattern in the surroundings of the tested producing well is affected while the well is closed. So the water coming from a dominant injector can move forward invading areas of a layer that have been previously occupied by other waters. Once the well is re-opened, if there is a tracer concentration contrast between the waters, a concentration change is registered. The concentration change was measured and also its recurrence in waters produced during inter-well tracer tests and during waterflooding that are employing different injection water from the formation one. Also it was determined the original flow distribution in the surrounding of the producing well by means of a simple balance of tracer mass. It is presented and analyze here the results from tests that were performed in an oil field of the Neuquina Basin. They allowed to visualizing the current condition of the bottom water flow as well as to make predictions on future performance. (authors)

  11. Temporal trends and sources of PCDD/Fs, pentachlorophenol and chlornitrofen in paddy field soils along the Yoneshiro River basin, Japan.

    Science.gov (United States)

    Kobayashi, Jun; Sakai, Mizuki; Kajihara, Hideo; Takahashi, Yukio

    2008-12-01

    In order to understand the long-term behaviors of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), pentachlorophenol (PCP), and 2,4,6-trichlorophenyl-4'-nitrophenyl ether (chlornitrofen, CNP) in paddy soil, we measured their concentrations in paddy soil samples collected in 1982 and 1984 (1980s) and in 2000 and 2002 (2000s) from the Yoneshiro River basin, Japan. The concentrations of PCP and CNP decreased from the 1980s to the 2000s, whereas the concentrations of PCDD/Fs and their toxic equivalency (WHO2006-TEQ) remained. The major sources of PCDD/Fs in the paddy soil samples were attributed to impurities in PCP and CNP as a result of comparisons of homologue and congener profiles and principal component analysis. Based on the results of comparison of total input and remaining amount, it is estimated that more than 99% of PCP and CNP applied to the paddy fields had disappeared, whereas most of the applied PCDD/Fs and TEQ remained.

  12. Seismic modeling, rock physics, avo and seismic attribute analysis for illuminating sandstone facies of the Late Ordovic Ian Mamuniyat Reservoir, R-Field, Murzuq Basin-Libya

    Science.gov (United States)

    Abushalah, Yousf Milad

    The Late Ordovician Mamuniyat Formation is the main hydrocarbon reservoir in the R-Field in Murzuq Basin, SW Libya. The Lower Mamuniyat, which is the only unit that was encountered in the study area, is composed of sandstone facies called Clean Mamuniyat and shaly sandstone facies called Dirty Mamuniyat. One major problem with the development of the R-Field is the difficulty of distinguishing the two units so this project was aimed to develop better methods for distinguishing between the two units of the Lower Mamuniyat. The other problem is to distinguish the transgressive shaly facies of the Bir Tlacsin, which has an impact on the hydrocarbon accumulation. Those issues manifested in limit of seismic resolution and interference that resulted from the converted shear mode waves. The dissertation was divided into three chapters. In the first chapter, seismic modeling using a deterministic and a Ricker wavelet were used to investigate the interference effects on the poststack seismic data and a bandpass filter was used to remove those effects. Instantaneous frequency, spectral-based colored inversion and rock physics were, then applied to determine the distributions of the sandstone facies of the Lower Mamuniyat Formation and to interpret the depositional setting of it. In the second chapter, spectral decomposition and inverted density were utilized to determine the distribution of the shaly facies of Bir Tlacsin, and its temporal thickness and to remap the top reservoir. In the last chapter, amplitude variation with offset (AVO) modeling, ray tracing, and spectral analysis were used to investigate the mode conversion and its effect on AVO signature, the amplitude of the near-mid and far offsets and frequency contents. Data enhancement then was performed using partial stacks and a bandpass filter.

  13. Genesis Model of Laozishan Geothermal Field, Subei Basin%苏北盆地老子山地热田成因模式

    Institute of Scientific and Technical Information of China (English)

    杨峰田; 庞忠和; 王彩会; 段忠丰; 罗璐; 李义曼

    2012-01-01

    老子山地热田是苏北盆地的典型地热田之一,阐明其成因模式对于该地热田的进一步开发和热水资源的可持续利用具有一定的指导意义.基于大地热流测试和水文地球化学方法对其进行了系统研究.结果表明:该区大地热流背景值为63.9 mW/m2,地热水与浅层地下水和地表水之间在水化学和同位素组成上存在明显差异.经分析,该地热系统属于中低温对流型.其补给区位于距地热田南部约60 km处的盱眙-张八岭一带的丘陵地区,热储温度为73~120℃,循环深度为2 350~4 200m,循环周期约为7 800 a,热水在区内NNE—SSW向与NW—SE向断裂的交汇处上涌,形成地热田.%Laozishan is a typical geothermal field in Subei Basin. We conducted a systematic study to explore into the genesis mechanism through heat flow measurement and hydrogeochemical investigation, for the purpose of further exploration and sustainable use of the geothermal resources. Results show that the background heat flow is 63. 9 mW/m2, and the hydrochemical and isotopic compositions of the thermal water are different from those of the shallow groundwater and surface water. Based on these data, the genesis model of the geothermal field has been postulated to be a low-medium temperature geothermal system of convective type. The recharge area is located in the Zhangbaling to the Xuyi mountain chain with a distance of about 60 km to the south of the geothermal field. The reservoir temperature of the geothermal field has been estimated to be 73 - 120 ℃ , with a water circulation depth of 2350-4200 m. The water age is about 7800 a. The thermal water flows upward in Laozishan area in the intersection zones of the faults striking NNE - SSW and NW - SE.

  14. The genesis of H2S in the Weiyuan Gas Field,Sichuan Basin and its evidence

    Institute of Scientific and Technical Information of China (English)

    ZHU GuangYou; ZHANG ShuiChang; LIANG YingBo; LI QiRong

    2007-01-01

    The Sinian Dengying Formation gas pool in Weiyuan is the oldest large-scale sulfur-bearing gas field in China,which has a H2S content ranging from 0.8% to 1.4%.The Cambrian Xixiangchi Formation gas pool discovered recently above the Dengying Formation contains gas geochemical behaviors similar to those of Dengying Formation but different in sulfur isotopes of H2S.Investigations show that though these two Sinian and Cambrian gas pools are separate ones,they share the same Cambrian source rock.The higher dry coefficient,heavier carbon isotopes,sulfur isotopes of sulfide,lower filling of gas pools,formation water characteristics,reservoir properties and H2S distribution,indicate that H2S in both the Sinian and Cambrian gas pools originates from TSR.The sulfur isotopes of sulfates have shown that H2S was formed in respective pools,namely hydrocarbons charged into the pools reacted with the Dengying Formation and the Xixiangchi Formation gypsum (TSR),respectively,to form H2S.Compared with sulfur isotopes of sulfates in each pool,δ34S values of H2S are 8‰ lighter for the Dengying Formation pool and 12‰ lighter for the Xixiangchi Formation pool,respectively,which is attributed to the difference in temperatures of TSR occurrence.The reservoir temperature of the Xixiangchi Formation pool is about 40℃ lower than that of the Dengying Formation pool.Temperature plays a controlling role in both the sulfur isotopic fractionation and amounts of H2S generation during TSR.

  15. Mechanism for calcite dissolution and its contribution to development of reservoir porosity and permeability in the Kela 2 gas field,Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This study is undertaken to understand how calcite precipitation and dissolution contributes to depth-related changes in porosity and permeability of gas-bearing sandstone reservoirs in the Kela 2 gas field of the Tarim Basin, Northwestern China. Sandstone samples and pore water samples are col-lected from well KL201 in the Tarim Basin. Vertical profiles of porosity, permeability, pore water chem-istry, and the relative volume abundance of calcite/dolomite are constructed from 3600 to 4000 m below the ground surface within major oil and gas reservoir rocks. Porosity and permeability values are in-versely correlated with the calcite abundance, indicating that calcite dissolution and precipitation may be controlling porosity and permeability of the reservoir rocks. Pore water chemistry exhibits a sys-tematic variation from the Na2SO4 type at the shallow depth (3600-3630 m), to the NaHCO3 type at the intermediate depth (3630―3695 m),and to the CaCl2 type at the greater depth (3728―3938 m). The geochemical factors that control the calcite solubility include pH, temperature, pressure, Ca2+ concen-tration, the total inorganic carbon concentration (ΣCO2), and the type of pore water. Thermodynamic phase equilibrium and mass conservation laws are applied to calculate the calcite saturation state as a function of a few key parameters. The model calculation illustrates that the calcite solubility is strongly dependent on the chemical composition of pore water, mainly the concentration difference between the total dissolved inorganic carbon and dissolved calcium concentration (i.e., [ΣCO2] -[Ca2+]). In the Na2SO4 water at the shallow depth, this index is close to 0, pore water is near the calcite solubility. Calcite does not dissolve or precipitate in significant quantities. In the NaHCO3 water at the intermedi-ate depth, this index is greater than 0, and pore water is supersaturated with respect to calcite. Massive calcite precipitation was observed at this depth

  16. The Aquitaine basin

    Energy Technology Data Exchange (ETDEWEB)

    Biteau, J.-J.; Le Marrec, A.; Le Vot, M.; Masset, J.-M.

    2006-07-01

    The Aquitaine Basin is located in the southwest of France, between the Gironde Arch in the north and the Pyrenean Mountain Chain in the south. It is a triangular-shaped domain, extending over 35000km{sup 2}. From north to south, six main geological provinces can be identified: (1) the Medoc Platform located south of the Gironde Arch; (2) the Parentis sub-basin; (3) the Landes Saddle; (4) the North Aquitaine Platform; (5) the foreland of the Pyrenees (also known as the Adour, Arzacq and Comminges sub-basins); and (6) the Pyrenean fold-and-thrust belt. Only the Parentis sub-basin, the foreland of the Pyrenean Chain and a minor part of the fold-and-thrust belt itself are proven hydrocarbon provinces. The Aquitaine Basin, in turn, is subdivided into four sub-basins - the Parentis, Adour-Arzacq, Tarbes and Comminges areas. The lozenge shape of these depocentres is related to the Hercynian tectonic framework of the Palaeozoic basement, reactivated during Early Cretaceous rifting. This rift phase aborted at the end of the Albian (prior to the development of an oceanic crust) in response to the beginning of the subduction of the Iberian plate under the European plate. During the Upper Cretaceous, continued subduction led to the creation of northwards-migrating flexural basins. In the Eocene, a paroxysmal phase of compression was responsible for the uplift of the Pyrenean Mountain Chain and for the thin-skinned deformation of the foreland basin. The resulting structuration is limited to the south by the internal core of the chain and to the north by the leading edge of the fold-and-thrust belt, where the Lacq and Meillon gas fields are located. Four main petroleum provinces have been exploited since the Second World War: (1) the oil-prone Parentis sub-basin and (2) salt ridges surrounding the Arzacq and Tarbes sub-basins; and (3) the gas-prone southern Arzacq sub-basin (including the external Pyrenean fold-and-thrust belt and the proximal foreland sub-basin) and (4

  17. Microbial Indicators, Pathogens, and Antibiotic Resistance in Groundwater Impacted by Animal Farming: Field Scale to Basin Scale

    Science.gov (United States)

    Harter, T.; Li, X.; Atwill, E. R.; Packman, A. I.

    2015-12-01

    three site scales on CAFOs and in ¼ of production aquifer samples near and away from CAFOs. Two thirds of E. coli and five in six Enterococcus exhibited resistance to multiple (> 2) antibiotics. Field monitoring results are consistent with fate and transport modeling that accounts for heterogeneity in aquifer systems.

  18. Objective Tracking of Tropical Cyclones in the North-West Pacific Basin Based on Wind Field Information only

    Science.gov (United States)

    Leckebusch, G. C.; Befort, D. J.; Kruschke, T.

    2016-12-01

    Although only ca. 12% of the global insured losses of natural disasters occurred in Asia, there are two major reasons to be concerned about risks in Asia: a) The fraction of loss events was substantial higher with 39% of which 94% were due to atmospheric processes; b) Asia and especially China, is undergoing quick transitions and especially the insurance market is rapidly growing. In order to allow for the estimation of potential future (loss) impacts in East-Asia, in this study we further developed and applied a feature tracking system based on extreme wind speed occurrences to tropical cyclones, which was originally developed for extra-tropical cyclones (Leckebusch et al., 2008). In principle, wind fields will be identified and tracked once a coherent exceedance of local percentile thresholds is identified. The focus on severe wind impact will allow an objective link between the strength of a cyclone and its potential damages over land. The wind tracking is developed in such a way to be applicable also to course-gridded AOGCM simulation. In the presented configuration the wind tracking algorithm is applied to the Japanese reanalysis (JRA55) and TC Identification is based on 850hPa wind speeds (6h resolution) from 1979 to 2014 over the Western North Pacific region. For validation the IBTrACS Best Track archive version v03r8 is used. Out of all 904 observed tracks, about 62% can be matched to at least one windstorm event identified in JRA55. It is found that the relative amount of matched best tracks increases with the maximum intensity. Thus, a positive matching (hit rate) of above 98% for Violent Typhoons (VTY), above 90% for Very Strong Typhoons (VSTY), about 75% for Typhoons (TY), and still some 50% for less intense TCs (TD, TS, STS) is found. This result is extremely encouraging to apply this technique to AOGCM outputs and to derive information about affected regions and intensity-frequency distributions potentially changed under future climate conditions.

  19. Far-Field Tsunami Impact in the North Atlantic Basin from Large Scale Flank Collapses of the Cumbre Vieja Volcano, La Palma

    Science.gov (United States)

    Tehranirad, Babak; Harris, Jeffrey C.; Grilli, Annette R.; Grilli, Stephan T.; Abadie, Stéphane; Kirby, James T.; Shi, Fengyan

    2015-12-01

    In their pioneering work, Ward and Day suggested that a large scale flank collapse of the Cumbre Vieja Volcano (CVV) on La Palma (Canary Islands) could trigger a mega-tsunami throughout the North Atlantic Ocean basin, causing major coastal impact in the far-field. While more recent studies indicate that near-field waves from such a collapse would be more moderate than originally predicted by Ward and Day [Løvholt et al. (J Geophy Res 113:C09026, 2008); Abadie et al. (J Geophy Res 117:C05030, 2012)], these would still be formidable and devastate the Canary Island, while causing major impact in the far-field at many locations along the western European, African, and the US east coasts. Abadie et al. (J Geophy Res 117:C05030, 2012) simulated tsunami generation and near-field tsunami impact from a few CVV subaerial slide scenarios, with volumes ranging from 20 to 450 km^3; the latter representing the most extreme scenario proposed by Ward and Day. They modeled tsunami generation, i.e., the tsunami source, using THETIS, a 3D Navier-Stokes (NS) multi-fluid VOF model, in which slide material was considered as a nearly inviscid heavy fluid. Near-field tsunami impact was then simulated for each source using FUNWAVE-TVD, a dispersive and fully nonlinear long wave Boussinesq model [ Shi et al. (Ocean Modell 43-44:36-51, 2012); Kirby et al. (Ocean Modeling, 62:39-55, 2013)]. Here, using FUNWAVE-TVD for a series of nested grids of increasingly fine resolution, we model and analyze far-field tsunami impact from two of Abadie et al.'s extreme CVV flank collapse scenarios: (i) that deemed the most "credible worst case scenario" based on a slope stability analysis, with a 80 km^3 volume; and (ii) the most extreme scenario, similar to Ward and Day's, with a 450 km^3 volume. Simulations are performed using a one-way coupling scheme in between two given levels of nested grids. Based on the simulation results, the overall tsunami impact is first assessed in terms of maximum surface

  20. A new evaluation method for micro-fracture plugging in high-temperature deep wells and its application: A case study of the Xushen Gas Field, Songliao Basin

    Directory of Open Access Journals (Sweden)

    Yonggui Liu

    2016-03-01

    Full Text Available Micro-fractures are developed in volcanic layers of Cretaceous Yingcheng Fm in the deep part of Xujiaweizi fault depression, Songliao Basin. In the process of well drilling, various complex problems happen, such as borehole wall slabbing and collapse and serious fluid leakage. Based on conventional drilling fluid plugging evaluation methods, the real situations cannot be presented accurately, especially in fracture feature simulation and plugging effect evaluation. Therefore, a specific micro-fracture plugging evaluation method was put forward especially for high-temperature deep wells in the paper. It is a new type of micro-fracture core model with the fracture apertures in the range of 1–50 μm. It is made of aluminosilicate that is compositionally close to natural rocks. It is good in repeatability with fracture-surface roughness, pore development and fracture-surface morphology close to natural fractures. Obviously, this new model makes up for the deficiencies of the conventional methods. A new micro-fracture plugging evaluation instrument was independently designed with operating temperature of 200 °C and operating pressure of 3.5–5.0 MPa. It can be used to simulate the flow regime of downhole operating fluids, with the advantages of low drilling fluid consumption, convenient operation and low cost. The plugging capacity of the organo-silicone drilling fluid system was evaluated by using this instrument. It is shown that the grain size distribution of the drilling fluid is improved and its anti-collapse capacity is enhanced. Based on the field test in Well XSP-3, the safe drilling problems in volcanic layers with developed micro-fractures are effectively solved by using the drilling fluid formula which is optimized by means of this evaluation method. And the safe drilling is guaranteed in the deep fractured formations in this area.

  1. Exploration potential of offshore northern California basins

    Energy Technology Data Exchange (ETDEWEB)

    Bachman, S.B.; Crouch, J.K.

    1988-01-01

    A series of exploratory wells was drilled in the northern California offshore basins in the 1960s following leasing of federal tracts off northern California, Oregon, and Washington. The drilling, although encountering numerous oil shows, was considered at the time to indicate low prospectivity in an area that extended as far south as the offshore Santa Maria basin. However, subsequent major discoveries in this decade in the offshore Santa Maria basin, such as the Point Arguello field, indicate that these offshore basins may be highly prospective exploration targets. Many of the key features of Monterey production in central and southern California are also present in the offshore basins of northern California. A new 5-year leasing plan has scheduled leasing in the northern California OCS starting in early 1989. The first basins on the schedule, the Point Arena and Eel River basins, differ in some respects. The Point Arena basin is more typical of a Monterey basin, with the potential for fractured chert reservoirs and organic-rich sections, deep burial of basinal sections to enhance the generation of higher gravity oils, and complex folding and faulting. The Eel River basin is more clastic-rich in its gas-producing, onshore extension. Key questions in the Eel River basin include whether the offshore, more distal stratigraphy will include Monterey-like biogenic sediments, and whether the basin has oil potential in addition to its proven gas potential. The Outer Santa Cruz basin shares a similar stratigraphy, structure, and hydrocarbon potential with the Point Arena basin. The Santa Cruz-Bodega basin, also with a similar stratigraphy, may have less exploration potential because erosion has thinned the Monterey section in parts of the basin.

  2. Programming Model with Zero Emissions of Chinese Qaidam Circular Economy Pilot Area%柴达木循环经济区的零排放规划模型

    Institute of Scientific and Technical Information of China (English)

    刘德海; 宋雯彦; 潘祺志; 王维国

    2014-01-01

    探讨零排放概念在柴达木循环经济试验区的区域规划中实际应用.首先,建立零排放线性规划模型,将工业废弃物的零排放目标作为约束性指标,将所有“零排放”的污染物“负产品”作为出基变量,优先替换掉;再根据θ准则,在所有资源量约束中选择资源约束最紧张、消耗系数最大的资源量,作为出基变量.其次,以柴达木循环经济区为案例,根据柴达木地区水资源和矿产资源可用量、废弃物的零排放和现有产能等约束条件,建立柴达木地区的零排放线性规划模型.模型求解得出试验区主要化工产品的最佳产量和最低治污设备数量,通过敏感性分析探讨了该区域的水资源关键性约束.柴达木循环经济区经济发展面临的一个关键约束是石油化工产品工业用水造成的水资源稀缺.需要合理利用地下和地表水资源,加强废水回收再利用,建立循环经济,实现可持续发展.%This paper applies the concept of zero emission into regional planning of Qaidam Circular Economy Pilot Area.Firstly,the paper builds a linear programming improved model of zero emission,which takes the zero-emission target of industrial wasters as the constraint condition,and puts forward the improved θ criterion for the decision of leaving basic variable in Simple method.Secondly,taking Qaidam Circular Economy Pilot Area as case,and considering the constraint conditions including available quantity of water and mineral resources,zero-emission of industrial wasters and existing production capacity,this paper builds the linear programming model with zero emissions of Qaidam area.It resolves the optimal expected outputs of main chemical products and minimal quantity of pollution treatment facilities in Qaidam area,and discusses the key restraint of water resource by sensitive analysis.The key restraint in Qaidam area is water resource consumed by petrochemical products.Therefore,it needs to use

  3. Structural imprints at the front of the Chocó-Panamá indenter: Field data from the North Cauca Valley Basin, Central Colombia

    Science.gov (United States)

    Suter, F.; Sartori, M.; Neuwerth, R.; Gorin, G.

    2008-11-01

    The northern Andes are a complex area where tectonics is dominated by the interaction between three major plates and accessory blocks, in particular, the Chocó-Panamá and Northern Andes Blocks. The studied Cauca Valley Basin is located at the front of the Chocó-Panamá Indenter, where the major Romeral Fault System, active since the Cretaceous, changes its kinematics from right-lateral in the south to left-lateral in the north. Structural studies were performed at various scales: DEM observations in the Central Cordillera between 4 and 5.7°N, aerial photograph analyses, and field work in the folded Oligo-Miocene rocks of the Serranía de Santa Barbara and in the flat-lying, Pleistocene Quindío-Risaralda volcaniclastic sediments interfingering with the lacustrine to fluviatile sediments of the Zarzal Formation. The data acquired allowed the detection of structures with a similar orientation at every scale and in all lithologies. These families of structures are arranged similarly to Riedel shears in a right-lateral shear zone and are superimposed on the Cretaceous Romeral suture. They appear in the Central Cordillera north of 4.5°N, and define a broad zone where 060-oriented right-lateral distributed shear strain affects the continental crust. The Romeral Fault System stays active and strain partitioning occurs among both systems. The southern limit of the distributed shear strain affecting the Central Cordillera corresponds to the E-W trending Garrapatas-Ibagué shear zone, constituted by several right-stepping, en-échelon, right-lateral, active faults and some lineaments. North of this shear zone, the Romeral Fault System strike changes from NNE to N. Paleostress calculations gave a WNW-ESE trending, maximum horizontal stress, and 69% of compressive tensors. The orientation of σ1 is consistent with the orientation of the right-lateral distributed shear strain and the compressive state characterizing the Romeral Fault System in the area: it bisects the

  4. Distribution and Sources of Trace Metals in Volcaniclastic Sediments of the SuSu Knolls Hydrothermal Field, Eastern Manus Basin, Papua New Guinea

    Science.gov (United States)

    Hrischeva, E. H.; Scott, S. D.

    2007-12-01

    Thirty-one sediment cores from the Suzette sulfide mound (renamed Solwara 1 by Nautilus Minerals Inc) in the SuSu Knolls hydrothermal field, eastern Manus back-arc basin, were studied in order to outline anomalies in metal concentrations within the mound and to explain the sources of the anomalies. The sediment cores were collected during expeditions of Nautilus Minerals Inc in 2006 and 2007. The work complements our previous study of metalliferous sediments of the SuSu Knolls and aims to provide guidelines for exploration for seafloor massive sulfide deposits in both modern and ancient back-arc environments. In contrast to mid-ocean ridges, the sedimentation in back-arc basins is more complex and involves deposition of large amount of volcaniclastic material that may mask the hydrothermal signal. The SuSu Knolls are covered by an apron of laminated dark gray volcanic sandy silts and silty sands composed of various amounts of volcanic rock fragments, volcanic glass, Ca plagioclase, pyroxene, cristobalite, Si-rich amorphous material, alunite, pyrite, barite and magnetite. In many cases the gray volcaniclastic sediments exhibit patches and layers having a black or greenish-brown color that contain fecal pellets. On the western slope of Suzette (Solwara 1), dark gray volcaniclastic sediments overlie greenish, greenish-brown and greenish-black volcaniclastic sediments containing up to 10 wt % clay-size component that comprises alteration products of volcanic glass such as smectite, chlorite and X-ray amorphous material. In most cases black and greenish-brown colored sediments contain fecal pellets at different stages of preservation. The distributions of Au (19 ppb to 2 ppm), Cu (159 ppm to 1 wt %), Zn (35 ppm to 1333 ppm), Pb (7 ppm to 977 ppm) and Ba (0.05 wt % to 2.8 wt %) outline patchy anomalies throughout the sediments of the mound. The study showed that some volcaniclastic sediments as deep as 25 cm below seafloor that are proximal to chimneys and chimney

  5. Effects of selected low-impact-development (LID) techniques on water quality and quantity in the Ipswich River Basin, Massachusetts-Field and modeling studies

    Science.gov (United States)

    Zimmerman, Marc J.; Barbaro, Jeffrey R.; Sorenson, Jason R.; Waldron, Marcus C.

    2010-01-01

    During the months of August and September, flows in the Ipswich River, Massachusetts, dramatically decrease largely due to groundwater withdrawals needed to meet increased residential and commercial water demands. In the summer, rates of groundwater recharge are lower than during the rest of the year, and water demands are higher. From 2005 to 2008, the U.S. Geological Survey, in a cooperative funding agreement with the Massachusetts Department of Conservation and Recreation, monitored small-scale installations of low-impact-development (LID) enhancements designed to diminish the effects of storm runoff on the quantity and quality of surface water and groundwater. Funding for the studies also was contributed by the U.S. Environmental Protection Agency's Targeted Watersheds Grant Program through a financial assistance agreement with Massachusetts Department of Conservation and Recreation. The monitoring studies examined the effects of (1) replacing an impervious parking lot surface with a porous surface on groundwater quality, (2) installing rain gardens and porous pavement in a neighborhood of 3 acres on the quantity and quality of stormwater runoff, and (3) installing a 3,000-square foot (ft2) green roof on the quantity and quality of stormwater runoff. In addition, the effects of broad-scale implementation of LID techniques, reduced water withdrawals, and water-conservation measures on streamflow in large areas of the basin were simulated using the U.S. Geological Survey's Ipswich River Basin model. From June 2005 to 2007, groundwater quality was monitored at the Silver Lake town beach parking lot in Wilmington, MA, prior to and following the replacement of the conventional, impervious-asphalt surface with a porous surface consisting primarily of porous asphalt and porous pavers. Changes in the concentrations of the water-quality constituents, phosphorus, nitrogen, cadmium, chromium, copper, lead, nickel, zinc, and total petroleum hydrocarbons, were monitored

  6. Spectral properties of carbonatized ultramafic mantle xenoliths and their host olivine basalts, Jabal Al Maqtal basin, South Eastern Desert, Egypt, using ASD FieldSpec spectroradiometer

    Directory of Open Access Journals (Sweden)

    Ahmed A. Madani

    2011-06-01

    Full Text Available Understanding the spectral properties of the carbonatized ultramafic mantle xenoliths and their host olivine basalts exposed at Jabal Al Maqtal strike-slip basin, south Eastern Desert, Egypt using portable ASD FieldSpec is the main task of this article. Field data revealed the presence of ultramafic mantle xenoliths at different stratigraphic levels within Jurassic olivine basalts. Ultramafic mantle xenoliths are recorded within highly altered olivine basalt topped by hard, compact brown conglomerate (erosional surface of 1.5 m thick. They have different sizes (5–25 cm and shapes (rounded, sub-rounded and elliptical. The spectral data are collected using ASD FieldSpec in sunny, free-cloud day. Data measurements were resampled as reference-target scan. Nearly all the mineralogical constituents of the studied ultramafic mantle xenoliths were replaced by Mg-Free (<0.5 wt% calcium carbonate (calcite. Spectrally the ultramafic mantle xenoliths can be categorized into two main groups based on their Fe and Mn content which produce absorption features at shorter wavelength regions. The spectral profile of the first group shows a pronounced absorption features around 0.50 μm, 0.65 μm and 0.90 μm wavelength regions. These features are attributed to the electronic processes within the unfilled d-shells of transition Mn2+ and Fe2+ metal cations (MnO and Fe2O3 content are 2.11 wt% and 12.6 wt% respectively as indicated by XRF analyses. The spectral profile of the second group shows a very week absorption features in shorter wavelength regions which is attributed to the low MnO (0.7 wt% and Fe2O3 (2.17 wt% content. Both ultramafic mantle xenoliths groups show pronounced absorption features in longer wavelength regions (1.8–2.55 μm. Inspection of the spectral profiles of the mantle xenoliths revealed the presence of six absorption features around 1.80 μm, 1.95 μm, 2.00 μm, 2.35 μm, 2.4 μm. and 2.5 μm wavelength regions which are

  7. Alberca De Guadalupe Maar Crater, Zacapu Basin : A Rare Type of Volcano within the Michoacán-Guanajuato Volcanic Field, México

    Science.gov (United States)

    Kshirsagar, P. V.; Siebe, C.; Guilbaud, M. N.; Salinas, S.

    2014-12-01

    Phreato-magmatic vents (esp. maar craters) are rare in the ~40,000 Km2 Plio-Quaternary monogenetic Michoacán-Guanajuato Volcanic Field (MGVF) located in the central part of the Mexican Volcanic Belt. In contrast to >1000 scoria cones, only 2 dozen phreato-magmatic monogenetic vents (e.g. tuff cones, tuff rings, and maars) have been identified. About half of these form a cluster near Valle de Santiago in the Lerma river valley at the northern margin of the MGVF, while the others occur in a rather scattered fashion. Here we discuss the origin of Alberca de Guadalupe maar crater, one of the three phreato-magmatic vents (in addition to El Caracol and Alberca de Los Espinos) that occur within the boundaries of the inter-montane lacustrine Zacapu basin, a tectonic graben bound by an ENE-WSW normal fault system. The maar crater came into existence between 20,000 and 23,000 y BP, forming a 140 m deep hole in the otherwise planar surrounding ground of theearly Pleistocene lava flows of Cerro Pelón.The maar crater has a diameter of ~1 Km and bears a 9 m deep lake. Eruptive products include typical surge deposits that are best exposed around the rim and inner crater walls. They are poorly sorted (Mdø= -1.56 to -3.75, ø= 1.43 to 3.23), rich in accidental lithics (angular andesitic lava and ignimbrite clasts) constituting 51-88% of the deposit with few juveniles (basaltic andesite with phenocrysts of plagioclase, olivine, and pyroxene in a quenched glassy matrix; SiO2=54-58 wt. %). Dry surge units are friable and clast-supported, in contrast the wet surge units are fairly indurated and bear accretionary lapilli. Bedding is frequently distorted by ballistic impact-sag structures. The entire construct is disrupted by an E-W trending regional fault, downthrowing the northern part by ~30 m.The unusual formation of this maar crater in the semi-arid highlands of Zacapu was favored by the local hydrological and topographical conditions. Such conditions still prevail in several

  8. Conditions of Formation of Secondary Quartz in Hydrothermally Altered, Subsurface Dacite beneath the Deep-Sea PACMANUS Hydrothermal Field, Manus Basin, Papua New Guinea

    Science.gov (United States)

    Vanko, D. A.; Wicker, S. G.; Binns, R. A.

    2006-05-01

    New fluid inclusion (FI) data from secondary quartz within the altered felsic rocks underlying the PACMANUS hydrothermal field provide additional constraints on the thermal conditions and fluid salinities accompanying hydrothermal alteration. PACMANUS, at a water depth of about 1650 to 1700 m on the summit of the neovolcanic Pual Ridge in the eastern part of the Manus backarc basin, is an active seafloor system situated in a felsic volcanic setting at a convergent plate boundary. Two sites of active venting - Roman Ruins, with high-temperature (220-276° C) sulfide chimneys, and Snowcap, which is an area of lower-temperature (6- 65° C) diffuse flow - were cored during Ocean Drilling Program Leg 193. Drilling reached sub-seafloor depths of 387 m at Snowcap and 206 m at Roman Ruins. At both Snowcap and Roman Ruins, fresh dacite/rhyodacite is underlain by highly to completely altered rocks with clays (illite, illite-smectite, chlorite, and mixed layer clays), disseminated pyrite, silica and late stage anhydrite. At shallow depths the silica is mostly cristobalite, whereas quartz is the polymorph at depth. Secondary quartz occurs in amygdules, alone or with accessory anhydrite and pyrite; in cm-scale granular nodules; and as tiny grains forming an open mosaic with interstitial clays and pore space. Scarce FI in secondary quartz are small (10-20μ), irregular, and contain liquid (L) plus vapor. Only a few are arrayed along healed fractures, and most are interpreted as primary. FI from Snowcap homogenize to L between 290° C and 390° C. Ice melting temperatures vary between about -10° C and -0.4° C, with most ice melting near -2.0° C. Thus, while most FI have near-seawater salinities, a significant number are much more saline, while others are much less saline, approaching fresh water. FI from Roman Ruins homogenize between 257° C and 370° C, and ice melting temperatures vary from about -14° C to -1.2° C. These data are best explained if the hydrothermal

  9. Tectono-stratigraphic evolution through successive extensional events of the Anydros Basin, hosting Kolumbo volcanic field at the Aegean Sea, Greece

    Science.gov (United States)

    Nomikou, P.; Hübscher, C.; Ruhnau, M.; Bejelou, K.

    2016-03-01

    The structural evolution of the South Aegean Sea is little explored due to the lack of marine seismic data. Our present day understanding is mainly based on some island outcrops and GPS measurements. In this study we discuss the rather incremental opening of the Anydros Basin in the Pliocene during six major tectonic pulses and the subsequent basin fill processes by interpreting seismic data and derived time isochore maps. Between the active pulses basin floor tilting persisted on a much lower rate. Seismic data illustrate the depositional processes in the emerging Anydros Basin. The observation of onlap fill strata, divergent reflection pattern, moat channels and contourite drifts imply that deposition was controlled by turbidity and contour currents as well as the tilting basin floor. The metamorphic Attico-Cycladic basement shows a rise that aligns along an NW-SE directed axis crossing Anydros island. This axis marks a structural change of the Santorini-Amorgos Ridge and thus represents a major structural boundary. Dip angles of NE-SW trending major faults, like the Santorini-Amorgos Fault, indicate normal faulting to be the superior mechanism forming the present horst and graben environment. Hence, the area is likely to be in a state of NW-SE directed extensional stresses forming the asymmetric graben structure of Anydros. Secondary fault clusters strike the same direction but show much steeper dip angles, possibly indicating strike-slip movement or resulting from deformational stresses along the hinge zones of the normal faults. The majority of the faults we discovered are located in the area of earthquake clusters, which is another indication of recent faulting. Ring faults around Kolumbo submarine volcano, result from caldera collapse and mark the diameter of the magma chamber approximately to 20 km.

  10. Organic carbon at a remote site of the western Mediterranean Basin: sources and chemistry during the ChArMEx SOP2 field experiment

    Directory of Open Access Journals (Sweden)

    V. Michoud

    2017-07-01

    Full Text Available The ChArMEx (Chemistry and Aerosols Mediterranean Experiments SOP2 (special observation period 2 field campaign took place from 15 July to 5 August 2013 in the western Mediterranean Basin at Ersa, a remote site in Cape Corse. During the campaign more than 80 volatile organic compounds (VOCs, including oxygenated species, were measured by different online and offline techniques. At the same time, an exhaustive description of the chemical composition of fine aerosols was performed with an aerosol chemical speciation monitor (ACSM. Low levels of anthropogenic VOCs (typically tens to hundreds of parts per trillion for individual species and black carbon (0.1–0.9 µg m−3 were observed, while significant levels of biogenic species (peaking at the ppb level were measured. Furthermore, secondary oxygenated VOCs (OVOCs largely dominated the VOC speciation during the campaign, while organic matter (OM dominated the aerosol chemical composition, representing 55 % of the total mass of non-refractory PM1 on average (average of 3.74 ± 1.80 µg m−3, followed by sulfate (27 %, 1.83 ± 1.06 µg m−3, ammonium (13 %, 0.90 ± 0.55 µg m−3 and nitrate (5 %, 0.31 ± 0.18 µg m−3. Positive matrix factorization (PMF and concentration field (CF analyses were performed on a database containing 42 VOCs (or grouped VOCs, including OVOCs, to identify the covariation factors of compounds that are representative of primary emissions or chemical transformation processes. A six-factor solution was found for the PMF analysis, including a primary and secondary biogenic factor correlated with temperature and exhibiting a clear diurnal profile. In addition, three anthropogenic factors characterized by compounds with various lifetimes and/or sources have been identified (long-lived, medium-lived and short-lived anthropogenic factors. The anthropogenic nature of these factors was confirmed by the CF analysis, which

  11. LA-ICPMS U-Pb Ages of Zircon from Metaleucosomes, Olongbuluke Microcontinent,North Qaidam, and Implications on the Response to the Global Rodinia Supercontinent Assembly Event in NW China

    Institute of Scientific and Technical Information of China (English)

    Wang Shuqing; Li Xiaoyan; Chen Nengsong; Wang Xinyu; Wang Qinyan; Liu Xiaoming

    2006-01-01

    U-Pb dating was conducted on different domains of zircons from metamorphosed leucosomes in Delingha (德令哈) complex, the lower basement rocks of the Olongbuluke (欧龙布鲁克) microcontinent, North Qaidam, in order to review its complex tectonothermal history. The zircon core is comprised of highly-modified magmatic zircon relicts, the zircon mantle was produced in response to anatexis of a Late Protoproterozoic thermal event; age and isotopic composition of both the zircon core and the zircon mantle have been seriously disturbed due to the thermal event related with growth of the zircon overgrowth rim. The 207 Pb/206 Pb apparent age of the overgrowth rim was estimated to be ~ 1 030 Ma. This Late Mesoproterozoic thermal event has been interpreted as a response to the global Rodinia supercontinent assembly event in the Olongbuluke microcontinent,Northwest China.

  12. Biomass from Short Rotation Energy Plantations of Black Locust on Tailing Dump of »Field B« Open Pit in »Kolubara« Mining Basin

    OpenAIRE

    Danilović, Milorad; Stojnić, Dušan; Vasiljević, Vladislav; Gačić, Dragan

    2013-01-01

    In recent decades, the establishment of short rotation energy plantations is becoming ever more common in marginal sites, including tailing dumps of open pits in mining basins. During the exploitation cycle, not only do short rotation energy plantations produce woody biomass for energy production, but they also accumulate large amounts of carbon from the soil and air. In this case, the energy plantations are primarily environmentally friendly, which is accompanied by their economic importance...

  13. APPLICATION OF WELL LOG ANALYSIS IN ASSESSMENT OF PETROPHYSICAL PARAMETERS AND RESERVOIR CHARACTERIZATION OF WELLS IN THE “OTH” FIELD, ANAMBRA BASIN, SOUTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Eugene URORO

    2014-12-01

    Full Text Available Over the past years, the Anambra basin one of Nigeria’s inland basins has recorded significant level of hydrocarbon exploration activities. The basin has been confirmed by several authors from source rock analyses to have the potential for generating hydrocarbon. For the hydrocarbon to be exploited, it is imperative to have a thorough understanding of the reservoir. Computer-assisted log analyses were employed to effectively evaluate the petrophysical parameters such as the shale volume (Vsh, total porosity (TP, effective porosity (EP, water saturation (Sw, and hydrocarbon saturation (Sh. Cross-plots of the petrophysical parameters versus depth were illustrated. Five hydrocarbon bearing reservoirs were delineated in well 1, four in well 2. The reservoirs in well 3 do not contain hydrocarbon. The estimated reservoir porosity varies from 10% to 21% while their permeability values range from 20md to 1400md. The porosity and permeability values suggest that reservoirs are good enough to store and also permit free flow of fluid. The volume of shale (0.05% to 0.35% analysis reveals that the reservoirs range from shaly sand to slightly shaly sand to clean sand reservoir. On the basis of petrophysics data, the reservoirs are interpreted a good quality reservoir rocks which has been confirmed with high effective porosity range between 20% and high hydrocarbon saturation exceeding 55% water saturation in well 1 and well 2. Water saturation 3 is nearly 100% although the reservoir properties are good.  

  14. Reduction of nitrogen, phosphorous and runoff by coordination controlled drainage with basin and ditch in paddy field%水稻沟田协同控制灌排模式的节水减污效应

    Institute of Scientific and Technical Information of China (English)

    朱成立; 郭相平; 刘敏昊; 汤树海

    2016-01-01

    Heavy rains occur frequently in South China during rice growth stages. The large amount of discharge from paddy field combined with high fertilization has caused serious environmental problems. The present controlled drainage methods pay much attention to holding more water in basins and reducing pollutant from basins, however, how to control runoff from field ditches and non-cultivated areas are often ignored. Coordinated Controlled Drainage (CCD) was proposed in the paper to solve the problem above by making most use of the wetland effects of both paddy field and field ditches that were widely distributed in the farmland in South China. The CCD technique tries to store rainwater in basins as much as possible by using rain-catching and controlled irrigation (RCCI) technique that maintains lower irrigation limit and higher water depth after rain depending on the waterlogging-tolerant and drought-tolerant ability of rice so as to reduce runoff from basins. Furthermore, it also impouned runoff from basins and non-cultivation lands such as roads, ditches and canals by a construction at the outlet of the field ditch. Field experiments were conducted in 2013 to verify the feasibility of the model. Controlled and uncontrolled drainages treatments were designed in rice field. Each controlled field of 4.5 hm2. Three replicates were designed. During the experiment, the drainage from field and trench were collected for determination of total nitrogen and phosphorus (TN and TP). Rice yield was measured. The results showed that at field scale, CCD could reduce evaportanspiration and water consumption by 18.8% and 15.3%, compared with frequent and shallow irrigation technique (FSI) respectively. Irrigation quote, drainage quote and irrigation frequency declined 28%, 60.6% and 4 times while TN and TP loss reduced 58.6% and 58.8%. At field control scale, surface drainage volume, the TN and TP burden from controlled ditch decreased by 55.9%, 59.7% and 66.7%, respectively under CCD

  15. SECONDARY NATURAL GAS RECOVERY IN THE APPALACHIAN BASIN: APPLICATION OF ADVANCED TECHNOLOGIES IN A FIELD DEMONSTRATION SITE, HENDERSON DOME, WESTERN PENNSYLVANIA

    Energy Technology Data Exchange (ETDEWEB)

    BOB A. HARDAGE; ELOISE DOHERTY; STEPHEN E. LAUBACH; TUCKER F. HENTZ

    1998-08-14

    The principal objectives of this project were to test and evaluate technologies that would result in improved characterization of fractured natural-gas reservoirs in the Appalachian Basin. The Bureau of Economic Geology (Bureau) worked jointly with industry partner Atlas Resources, Inc. to design, execute, and evaluate several experimental tests toward this end. The experimental tests were of two types: (1) tests leading to a low-cost methodology whereby small-scale microfractures observed in matrix grains of sidewall cores can be used to deduce critical properties of large-scale fractures that control natural-gas production and (2) tests that verify methods whereby robust seismic shear (S) waves can be generated to detect and map fractured reservoir facies. The grain-scale microfracture approach to characterizing rock facies was developed in an ongoing Bureau research program that started before this Appalachian Basin study began. However, the method had not been tested in a wide variety of fracture systems, and the tectonic setting of rocks in the Appalachian Basin composed an ideal laboratory for perfecting the methodology. As a result of this Appalachian study, a low-cost commercial procedure now exists that will allow Appalachian operators to use scanning electron microscope (SEM) images of thin sections extracted from oriented sidewall cores to infer the spatial orientation, relative geologic timing, and population density of large-scale fracture systems in reservoir sandstones. These attributes are difficult to assess using conventional techniques. In the Henderson Dome area, large quartz-lined regional fractures having N20E strikes, and a subsidiary set of fractures having N70W strikes, are prevalent. An innovative method was also developed for obtaining the stratigraphic and geographic tops of sidewall cores. With currently deployed sidewall coring devices, no markings from which top orientation can be obtained are made on the sidewall core itself during

  16. Remote sensing and field analysis of the Palaeozoic structural style in NW Libya: The Qarqaf arch a paleo-transfer fault zone between the Ghadamis and Murzuq basins

    Science.gov (United States)

    Chorowicz, Jean; Benissa, Mahmoud

    2016-11-01

    The N75°E-trending Qarqaf arch in NW Libya separates the Ghadamis and Murzuq basins. We have updated existing geological maps by remote sensing analysis and fieldwork in order to describe the tectonic style of the Palaeozoic units. We have evidenced a Bir Aishah anticline, a Wadi Ash Shabiyat graben and arrays of sedimentary and/or vein quartz dykes that relate to extension fractures or open faults some of them being filled up by on-going sedimentation. We show that continuous brittle syn-depositional deformation occurred throughout the Palaeozoic and progressively with time focused into major faults. The Qarqaf arch is a Palaeozoic right-lateral fault zone comprising main conjugate dextral N60°E and sinistral N90°E fault families. It also comprises ∼ N-striking extensional faults with related drag or fault-propagation folds. The Palaeozoic tectonic style is that of rift basins connected by a major transfer fault zone. The arch is as a consequence of strike-slip mechanism. In order to account for distinct folds affecting the Carboniferous strata we argue that partly consolidated silty Devonian and Carboniferous deposits slid in mass by places at the end of their deposition over tilting Devonian layers. Our model is alternative to the currently considered concept of major Variscan compressional orogen in this area. The regional so called 'Variscan' age disconformity actually is the Triassic early Neo-Tethyan event. These general concepts have potential impact on basin modelling of subsidence, uplift, thermal history and hydrocarbon migration. Any new structural geology study in this area is important for oil exploration.

  17. Recharge sources and hydrogeochemical evolution of groundwater in semiarid and karstic environments: A field study in the Granada Basin (Southern Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Kohfahl, Claus [Freie Universitaet Berlin, Institute of Geological Sciences, Malteserstr. 74-100, D-12249 Berlin (Germany)], E-mail: kohfahl@zedat.fu-berlin.de; Sprenger, Christoph [Freie Universitaet Berlin, Institute of Geological Sciences, Malteserstr. 74-100, D-12249 Berlin (Germany); Herrera, Jose Benavente [Instituto del Agua de la Universidad de Granada, Ramon y Cajal, 4, 18071 Granada (Spain); Meyer, Hanno [Isotope Laboratory of the Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A 43, 14473 Potsdam (Germany); Chacon, Franzisca Fernandez [Dpto. Hidrogeologia y Aguas Subterraneas, Instituto Geologico y Minero de Espana, Oficina de Proyectos, Urb. Alcazar del Genil 4, Edificio Zulema bajo, 18006 Granada (Spain); Pekdeger, Asaf [Freie Universitaet Berlin, Institute of Geological Sciences, Malteserstr. 74-100, D-12249 Berlin (Germany)

    2008-04-15

    The objective of this study is to refine the understanding of recharge processes in watersheds representative for karstic semiarid areas by means of stable isotope analysis and hydrogeochemistry. The study focuses on the Granada aquifer system which is located in an intramontane basin bounded by high mountain ranges providing elevation differences of almost 2900 m. These altitude gradients lead to important temperature and precipitation gradients and provide excellent conditions for the application of stable isotopes of water whose composition depends mainly on temperature. Samples of rain, snow, surface water and groundwater were collected at 154 locations for stable isotope studies ({delta}{sup 18}O, D) and, in the case of ground- and surface waters, also for major and minor ion analysis. Thirty-seven springs were sampled between 2 and 5 times from October 2004 to March 2005 along an altitudinal gradient from 552 masl in the Granada basin to 2156 masl in Sierra Nevada. Nine groundwater samples were taken from the discharge of operating wells in the Granada basin which are all located between 540 and 728 masl. The two main rivers were monitored every 2-3 weeks at three different altitudes. Rainfall being scarce during the sampling period, precipitation could only be sampled during four rainfall events. Calculated recharge altitudes of springs showed that source areas of mainly snowmelt recharge are generally located between 1600 and 2000 masl. The isotope compositions of spring water indicate water sources from the western Mediterranean as well as from the Atlantic without indicating a seasonal trend. The isotope pattern of the Quaternary aquifer reflects the spatial separation of different sources of recharge which occur mainly by bankfiltration of the main rivers. Isotopic signatures in the southeastern part of the aquifer indicate a considerable recharge contribution by subsurface flow discharged from the adjacent carbonate aquifer. No evaporation effects due

  18. Crustal structure and rift tectonics across the Cauvery–Palar basin, eastern continental margin of India based on seismic and potential field modelling

    Digital Repository Service at National Institute of Oceanography (India)

    Twinkle, D.; Rao, G.S.; Radhakrishna, M.; Murthy, K.S.R.

    er oz oi c D yk es Ve da ra n ya m te rr ac e Puliact Depression Pu liac t La ke b C he nn ai Ti ru ch ir ap al li 88 48 08 10141822 IN D IA Cud dap ah B asin Cauv ery P alar B asinKr ish na Go da va ri Ba sin M ah... and these trends are in conformity with the Eastern Ghats trend. The major structural and tectonic elements observed in the Cauvery–Palar basin (after Prabhakar and Zutshi 1993; Bastia and Radhakrishna 2012) are: (i) Pulicat depression defined by Nayudupetta high...

  19. 大型高原内陆咸化湖盆油气特殊成藏条件分析及勘探意义——以柴达木盆地柴西地区为例%Special reservoir formation conditions and their exploration significance of the large saline lacustrine basin of inland plateau-taking the western Qadam Basin for example

    Institute of Scientific and Technical Information of China (English)

    石亚军; 曹正林; 张小军; 王艳清; 王鑫; 黄思静

    2011-01-01

    -directional migration potential of oil and gas. Finally, reservoirs in active re-gions at higher altitude show a "self-closed" pooling pattern. Based on the above four specific reservoiring conditions, the author proposed that oil and gas exploration in western Qadam Basin shall not only focus on delta front deposits, but also on the following three targets: beach bar sand, algal limestone as well as slump and tur-bidite sandbody caused by earthquakes. In addition, the above-mentioned features determine that the oil fields in western Qaidam have the characteristics of near-source accumulation, wide distribution, small but numerous oil/gas fields. Thus the exploration should be mainly brought before areas close to the main kitchens, such as Altun, Gansen and along Honggouzi. Meanwhile, the understanding of so-called "self-closed" reservoiring pointed out that the uplifted basin margin be the main areas for future reserve growth.

  20. Examination of Global Seismic Tomography Images and Sea-Surface Magnetic Field Anomaly Profiles in the West Philippine Basin for the Large Clockwise Rotation of the Philippine Sea Plate during the Last 55 Million Years

    Science.gov (United States)

    Choe, H.; Lee, S. M.

    2014-12-01

    The Philippine Sea Plate is thought to have undergone a 90° clockwise rotation during the last 55 million years. However, evidences for such an argument are rather circumstantial. For instance, paleomagnetic measurements for the large rotation are derived largely from Halmahera, Indonesia which is quite close to the plate boundary. It is thus possible that this region may have undergone local deformation separate from the main parts of the Philippine Sea Plate. In this study, we examine the global seismic tomography images of the mantle beneath the Philippine Sea Plate and the marine magnetic field anomaly data at the sea surface from the West Philippine Basin to see whether they agree with the presumed motion of the Philippine Sea Plate. Our comparison between the plate reconstruction and global tomography suggests that the rotation of Philippine Sea Plate may not have been continuous but instead experienced a temporal break at around 32 Ma. The exact nature of this pause is uncertain, but it may be related to a sudden change in the configuration of subduction systems. A detail comparison with recent results from IODP Legs 350 and 351 is therefore necessary, including a search for a change in the depositional style of basin sediment. We also examined the detailed the shape of magnetic anomalies (such as skewness) and compare them with the previous model by allowing the magnetization to have direction corresponding to that during the opening of the West Philippine Basin. At this moment, it is too early to tell if the sudden change at around 32 Ma or other inferred breaks can be seen in the magnetic profiles as well.

  1. Vp/Vs-ratios from the central Kolbeinsey Ridge to the Jan Mayen Basin, North Atlantic; implications for lithology, porosity and present-day stress field

    Science.gov (United States)

    Mjelde, Rolf; Aurvåg, Roar; Kodaira, Shuichi; Shimamura, Hideki; Gunnarsson, Karl; Nakanishi, Ayako; Shiobara, Hajime

    The horizontal components from twenty Ocean Bottom Seismometers deployed along three profiles near the Kolbeinsey Ridge, North Atlantic, have been modelled with regard to S-waves, based on P-wave models obtained earlier. Two profiles were acquired parallel to the ridge, and the third profile extended eastwards across the continental Jan Mayen Basin. The modelling requires a thin (few 100 m) layer with very high Vp/Vs-ratio (3.5-9.5) at the sea-floor in the area lacking sedimentary cover. The obtained Vp/Vs-ratios for the remaining part of layer 2A, 2B, 3 and upper mantle, correspond to the following lithologies: pillow lavas, sheeted dykes, gabbro and peridotite, respectively. All crustal layers exhibit a decreasing trend in Vp/Vs-ratio away-from-the-axis, interpreted as decreasing porosity and/or crack density in that direction. A significant S-wave azimuthal anisotropy is observed within the thin uppermost layer of basalt near the ridge. The anisotropy is interpreted as being caused by fluid-filled microcracks aligned along the direction of present-day maximum compressive stress, and indicates crustal extension at the ridge itself and perpendicular-to-the-ridge compression 12 km off axis. Spreading along the Kolbeinsey Ridge has most likely been continuous since its initiation ca. 25 Ma: The data do not suggest the presence of an extinct spreading axis between the Kolbeinsey Ridge and the Aegir Ridge as has been proposed earlier. The Vp/Vs-ratios found in the Jan Mayen Basin are compatible with continental crust, overlain by a sedimentary section dominated by shale.

  2. Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)

    Science.gov (United States)

    Omodeo Salè, Silvia; Guimerà, Joan; Mas, Ramón; Arribas, José

    2014-09-01

    The Cameros Basin is a part of the Mesozoic Iberian Rift. It is an extensional basin formed during the late Jurassic and early Cretaceous, in the Mesozoic Iberian Rift context, and it was inverted in the Cenozoic as a result of the Alpine contraction. This work aims to reconstruct the tectono-stratigraphic evolution of the basin during the Mesozoic, using new and revised field, geophysical and subsurface data. The construction of a basin-wide balanced section with partial restorations herein offers new insights into the geometry of the syn-rift deposits. Field data, seismic lines and oil well data were used to identify the main structures of the basin and the basin-forming mechanisms. Mapping and cross-sectional data indicate the marked thickness variation of the depositional sequences across the basin, suggesting that the extension of the depositional area varied during the syn-rift stage and that the depocentres migrated towards the north. From field observation and seismic line interpretation, an onlap of the depositional sequences to the north, over the marine Jurassic substratum, can be deduced. In the last few decades, the structure and geometry of the basin have been strongly debated. The structure and geometry of the basin infill reconstructed herein strongly support the interpretation of the Cameros Basin as an extensional-ramp synclinal basin formed on a blind south-dipping extensional ramp. The gradual hanging-wall displacement to the south shifted the depocentres to the north over time, thus increasing the basin in size northwards, with onlap geometry on the pre-rift substratum. The basin was inverted by means of a main thrust located in a detachment located in the Upper Triassic beds (Keuper), which branched in depth with the Mesozoic extensional fault flat. The reconstruction of the tectono-stratigraphic evolution of the Cameros Basin proposed herein represents a synthesis and an integration of previous studies of the structure and geometry of the

  3. Comparison of Factorial Kriging Analysis Method and Upward Continuation Filter to Recognize Subsurface Structures — A Case Study: Gravity Data from a Hydrocarbon Field in the Southeast Sedimentary Basins of the East Vietnam Sea

    Science.gov (United States)

    Azad, Mohammad-Reza; Koneshloo, Mohammad; Kamakar Rouhani, Abolghasem; Aghajani, Hamid

    2016-04-01

    To interpret geophysical anomaly maps, it is necessary to filter out regional and sometimes noise components. Each measured value in a gravity survey consists of different components. Upward continuation (UC) is one of the most widely used filters. The shortcoming of this filter is not to consider the spatial structure of the data, and also the fact that the trial and error approach and expert's judgment are needed to adjust it. This study aims to compare the factorial kriging analysis (FKA) and UC filters for separation of local and regional anomalies in the gravity data of a hydrocarbon field in the southeast sedimentary basins of the East Vietnam Sea. As shown in this paper, FKA method permits to filter out all of the identified structures, while the UC filter does not possess this capability. Therefore, beside general and classic filtering methods, the FKA method can be used as a strong method in filtering spatial structures and anomaly component.

  4. Water Accounting from Ungauged Basins

    Science.gov (United States)

    Bastiaanssen, W. G.; Savenije, H.

    2014-12-01

    Water scarcity is increasing globally. This requires a more accurate management of the water resources at river basin scale and understanding of withdrawals and return flows; both naturally and man-induced. Many basins and their tributaries are, however, ungauged or poorly gauged. This hampers sound planning and monitoring processes. While certain countries have developed clear guidelines and policies on data observatories and data sharing, other countries and their basin organization still have to start on developing data democracies. Water accounting quantifies flows, fluxes, stocks and consumptive use pertaining to every land use class in a river basin. The objective is to derive a knowledge base with certain minimum information that facilitates decision making. Water Accounting Plus (WA+) is a new method for water resources assessment reporting (www.wateraccounting.org). While the PUB framework has yielded several deterministic models for flow prediction, WA+ utilizes remote sensing data of rainfall, evaporation (including soil, water, vegetation and interception evaporation), soil moisture, water levels, land use and biomass production. Examples will be demonstrated that show how remote sensing and hydrological models can be smartly integrated for generating all the required input data into WA+. A standard water accounting system for all basins in the world - with a special emphasis on data scarce regions - is under development. First results of using remote sensing measurements and hydrological modeling as an alternative to expensive field data sets, will be presented and discussed.

  5. Efficient Exploration and Development of Carboniferous Volcanic Gas Field in Kelameili Area in Junggar Basin%克拉美丽石炭系火山岩气田的高效勘探开发

    Institute of Scientific and Technical Information of China (English)

    董雪梅; 徐怀民; 贺陆明; 任军民; 吴静

    2012-01-01

    Volcanic oil-gas exploration in Junggar basin started in 1950's.In recent years,through comprehensive researches of hydrocarbon accumulation conditions of the Carboniferous volcanic reservoirs,Ludong-Wucaiwan area is chosen as major exploration target to carry out systematic studies and make technological breakthrough,thus deepening the knowledge of volcanic reservoir,establishing the exploration thought of reservoir controls dominated by volcanic rock body,based on which the matched technologies were developed,and the breakthroughs have been made in drilling of volcanic rock body as main target in Dinan bulge.A hundred billion cubic meters of Kelameili gas field with both source and reservoir in Carboniferous system was proved in two years and the first large-scale integrated volcanic gas field in Junggar basin is discovered.Up to now,it has been brought into the scale and efficient production.The Carboniferous volcanic reservoirs have become an important domain for oil-gas exploration in Junggar basin.%准噶尔盆地火山岩油气勘探始于20世纪50年代,近年来通过准噶尔盆地石炭系油气成藏条件综合研究,优选陆东—五彩湾地区作为勘探主战场,展开针对石炭系火山岩的系统研究和技术攻关,不断深化成藏认识,确立了以火山岩岩体控藏的勘探思路,研发了与之相应的配套技术,在滴南凸起上以火山岩岩体为主要目标展开钻探获得突破,探明了千亿方的石炭系自生自储的克拉美丽气田,形成准噶尔盆地第一个大型整装火山岩气田,并已实现规模高效开发。石炭系火山岩已经成为准噶尔盆地油气勘探的重要领域。

  6. Reactivation of an Idle Lease to Increase Heavy Oil Recovery through Application of Conventional Steam Drive Technology in a Low Dip Slope and Basin Reservoir in the Midway-Sunset Field, San Jaoquin Basin, California

    Energy Technology Data Exchange (ETDEWEB)

    Deo, M.; Forster, C.; Jenkins, C.; Schamel, S.; Sprinkel, D.; and Swain, R.

    1999-02-01

    This project reactivates ARCO's idle Pru Fee lease in the Midway-Sunset field, California and conducts a continuous steamflood enhanced oil recovery demonstration aided by an integration of modern reservoir characterization and simulation methods. Cyclic steaming was used to reestablish baseline production within the reservoir characterization phase of the project completed in December 1996. During the demonstration phase begun in January 1997, a continuous steamflood enhanced oil recovery is testing the incremental value of this method as an alternative to cyclic steaming. Other economically marginal Class III reservoirs having simular producibility problems will benefit from insight gained in this project. The objectives of the project are: (1) to return the shut-in portion of the reservoir to optimal commercial production; (2) to accurately describe the reservoir and recovery process; and (3) to convey the details of this activity to the domestic petroleum industry, especially t o other producers in California, through an aggressive technology transfer program.

  7. Survey management in directional wells in Polvo Field - Campos Basin; Gerenciamento de 'surveys' em pocos direcionais no Campo de Polvo - Bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Fernando; Antunes, Francisco; Rafainer, Gilberto [HALLIBURTON, Rio de Janeiro, RJ (Brazil). Sperry Drilling Services; Ohara, Shiniti [Devon Energy do Brasil Ltda., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Magnetic Surveying Techniques are fully used in order to control the well path in drilling operations, and electronic tools, known as Measure While Drilling (MWD), uses the intensity and inclination of Earth's magnetic field as a reference for its inputs. These tools have three magnetometers and three accelerometers spaced 90 degrees apart which measure the components of magnetic field and gravitational field to calculate the inclination, the direction of the well, and the tool face orientation. Erroneous readings can occur due to the magnetic interference since the Earth magnetic field can be affected by external sources such as, magnetized materials in the BHA (axial), casings strings or near by wells (cross axial), and these abnormal readings are enough to put the well bore far away from its desired location. In this paper we intend to show the methodology and software usage to allow magnetic field strength exam and identification of systematic failures in mechanization or calibration of the electronics tools. Moreover, the use of enhancements as In-Field Referencing (IFR) or Interpolated In Field Referencing (IIFR) in sensors calculation are described. Furthermore, the results obtained comparing the solutions with gyroscope survey data is shown. (author)

  8. Radioactivity and radiogenic heat production in the oil field of the Reconcavo Basin; Radioatividade e geracao de calor radiogenico em pocos petroliferos na Bacia do Reconcavo

    Energy Technology Data Exchange (ETDEWEB)

    Alves Junior, Paulo B.; Argollo, Roberto M. de [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Centro de Pesquisa em Geofisica e Geologia

    2004-07-01

    The production of radiogenic heat in the terrestrial crust is due mainly to U, Th and K presents in the rocks. In this work, we use the gamma-ray spectrometry technique to determine the contents of these elements in drill cuttings and obtaining profiles of heat production rates in oils wells of the Reconcavo basin. In the total, we measure 640 samples of drill cuttings from wells FFL-1 and MGP-34 ceded by PETROBRAS. The thorium contents vary from 1.6 to 25.5 ppm, the uranium contents varied from 0.5 to 5.82 ppm, the potassium samples varied from 0.05 to 2.25 % and the production rates of radiogenic heat varied among 0.50 to 10.85 10{sup -4} {mu}W kg{sup -1}. With the profiles heat production rates obtained, a correlation was verified among these rates and the lithologies at wells FFL-1 and MGP-34. These values will be used in the correlation between these samples at wells and the sample collected at blooming. (author)

  9. Evaluating prediction uncertainty of areas contributing recharge to well fields of multiple water suppliers in the Hunt-Annaquatucket-Pettaquamscutt River Basins, Rhode Island

    Science.gov (United States)

    Friesz, Paul J.

    2012-01-01

    Three river basins in central Rhode Island-the Hunt River, the Annaquatucket River, and the Pettaquamscutt River-contain 15 production wells clustered in 4 pumping centers from which drinking water is withdrawn. These high-capacity production wells, operated by three water suppliers, are screened in coarse-grained deposits of glacial origin. The risk of contaminating water withdrawn by these well centers may be reduced if the areas contributing recharge to the well centers are delineated and these areas protected from land uses that may affect the water quality. The U.S. Geological Survey, in cooperation with the Rhode Island Department of Health, began an investigation in 2009 to improve the understanding of groundwater flow and delineate areas contributing recharge to the well centers as part of an effort to protect the source of water to these well centers. A groundwater-flow model was calibrated by inverse modeling using nonlinear regression to obtain the optimal set of parameter values, which provide a single, best representation of the area contributing recharge to a well center. Summary statistics from the calibrated model were used to evaluate the uncertainty associated with the predicted areas contributing recharge to the well centers. This uncertainty analysis was done so that the contributing areas to the well centers would not be underestimated, thereby leaving the well centers inadequately protected. The analysis led to contributing areas expressed as a probability distribution (probabilistic contributing areas) that differ from a single or deterministic contributing area. Groundwater flow was simulated in the surficial deposits and the underlying bedrock in the 47-square-mile study area. Observations (165 groundwater levels and 7 base flows) provided sufficient information to estimate parameters representing recharge and horizontal hydraulic conductivity of the glacial deposits and hydraulic conductance of streambeds. The calibrated value for recharge

  10. A discussion on gas sources of the Feixianguan Formation H2S-rich giant gas fields in the northeastern Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In recent years several H2S-rich oolite giant gas pools have been discovered in the Lower Triassic Feixianguan Formation of the northeastern Sichuan basin, and their explored gas reserves have been over 5000x108 m3. However, gas sources remain unsolved due to multiple source horizons with high maturity in this area and TSR alterations. By integrating analytical data of natural gas samples with conprehensive investigations on many factors, such as oil-gas geology, distribution and evolution of source rocks, charging and adjustment of gas pools, mixture of natural gases and secondery alterations, the present study concluded that the dominant source for the Feixianguan Fr. gas pools is the Permian Longtan Fr. source rock and secondly the Silurian Longmaxi Fr. source rock. Natural gases from the various gas pools differ genetically due to the matching diversity of seal configurations with phases of hydrocarbon generation and expulsion by different source rocks, among which natural gases in Puguang Gasfield are dominated by the trapped gas generated from the Longtan Fr. source rock and commingled with the gas cracked from the Silurian crude oil, while those in Dukouhe,Tieshangpo and Luojiazhai Gasfields are composed mainly of the Silurian oil-cracking gas and commingled with the natural gas derived from the Longtan Fr. source rock.

  11. Paleo-oil-Water Contact and Present-Day Gas-Water Contact:Implication for Evolution History of Puguang Gas Field,Sichuan Basin,China

    Institute of Scientific and Technical Information of China (English)

    Li Pingping; Zou Huayao; Zhang Yuanchun; Wang Cunwu; Zhang Xuefeng

    2008-01-01

    The Puguang (普光) gas field is the largest gas field found in marine carbonate in China.The Puguang gas field experienced complicated evolution history from paleo-oil pool to gas pool.The purpose of this article is to reveal the evolution history of Puguang gas field through systematic study on the relationship between paleo-oil-water contact (POWC) and present-day gas-water contact (PGWC).POWC was recognized by observing the change of relative content of residual solid bitumen in the cores,and PGWC was observed using log and drilling stem test data.Two types of relationship between POWC and PGWC were observed in the Puguang gas field:POWC is above PGWC,and POWC is below PGWC.The former is normal as oil cracking may cause gas-water contact to move downward.The latter can be interpreted by lateral gas re-migration and re-accumulation caused by changes in structural configuration.The relationship between POWC and PGWC suggests that during oil charge,the southwestern and northwestern parts of the Puguang gas field were structurally lower than the northeastern and southeastern parts.Thrusting from Xuefengshan (雪峰山) since Yanshanian movement and from Dabashan (大巴山) since Himalayan movement resulted in the relative uplift of the southwestern and northwestern parts of the Puguang structure,which significantly changed the structural configuration.Based on the paleo-structure discussed in this article,the most probable migration directions of paleo-oil were from the northwest to the southeast and from the southwest to the northeast.Consequently,the evolution history of the Puguang gas field can be divided into three stages,namely,oil charging (200-170 Ma),cracking oil to gas (155-120 Ma),and gas pool adjustment (1200-0Ma).

  12. Sequence and sedimentary features of the Changxing Fm organic reefs and their control on reservoir development in the Yuanba Gas Field, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Hongtao Li

    2015-12-01

    Full Text Available In the Yuanba area, Sichuan Basin, the gas reservoirs in the Upper Permian Changxing Fm are now at the development stage. With the smooth progress of development, it is urgent to characterize the reservoir architectures accurately and summarize the controlling factors for reservoir development. In this paper, research was mainly performed on the Changxing Fm organic reefs in terms of their sequence stratigraphy, sedimentary facies, and reservoir characteristics and architectures based on core observation and thin section analysis, combined with physical property data and logging curves analysis results. It is shown that the Changing Fm can be divided into two third-order sequences and six fourth-order sequences, their electric logs are characterized by abrupt change above and below the high-frequency sequence boundary and are consistent with the sedimentary cycles controlled by high-frequency sequences. Besides, the Changxing Fm organic reefs mainly represents zonal distribution outside SQ2 platform margin, and they are vertically composed of two obvious two reef sedimentary cycles and laterally developed in asymmetric patterns (early in the east and late in the west. Finally, in general, organic reef (bank. reservoirs are mainly composed of low-porosity and moderate–low-permeability dissolved dolomite reservoirs, and they are mostly distributed at reef caps in the upper–middle parts of the two fourth-order sequences, with the characteristics of multiple beds, thin single beds, different types of reservoirs with different thickness interbedded with each other, strong heterogeneity and double-layer reservoir architectures. It is concluded that the distribution of organic reef microfacies in this area is controlled by high-frequency sequence, which is the key controlling factor for reservoir development and spatial distribution.

  13. Water isotopic characterization of hypersaline formation of a petroleum field Reconcavo basin, Brazil; Caracterizacao isotopica de aguas de formacao hipersalinas de um campo de petroleo da Bacia do Reconcavo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Teles, Danilo Ribeiro de Sa; Azevedo, Antonio Expedito Gomes de, E-mail: danilosateles@yahoo.com.br, E-mail: expedito@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Fisica. Centro de Pesquisa em Geofisica e Geologia; Santos, Christian Pereira Lopes dos, E-mail: cplsgs@gmail.com [Instituto Federal Baiano, Salvador, BA (Brazil)

    2010-04-15

    Formation water is the water present in reservoir rock pores, produced together with petroleum. Usually it is hyper saline with concentrations that can be higher than 250 g/l of dissolved solids. The concentration of the dissolved elements and the isotopic composition of the water and of some of the dissolved elements can be excellent tracers to study the dynamic of underground fluid flux, the mixing of distinct sources and the origin of salinization of these waters. This work reports the isotopic composition ({delta}{sup 2}H , {delta}{sup 18}O) and electrical conductivity (EC) of formation waters from 10 wells of a petroleum field of the Reconcavo Basin, looking for their evolution, interaction with the minerals and rocks and reservoir interconnection. The samples have electric conductivity ranging from 84 to 137 mS/cm, with conductivity increasing with depth of production zone. It is observed an enrichment of deuterium and oxygen-18 with the depth of production zone, probably due to water-rock interactions that were probably increased by higher temperatures of the deeper levels and longer residence times. The samples from the production zone between 1450 to 1520 m, drained by 7 of the 10 wells sampled, show a small range in isotopic composition and in electric conductivity, indicating homogeneity in this level of the reservoir. In the shallow level of 450 m the values of {delta}{sup 2}H , {delta}{sup 18}O and EC are lower, with isotopic composition similar to the oceanic water, possibly representing the original water that entered the reservoir during the sedimentation of the basin. (author)

  14. Study on Evolution Law of Groundwater’s Dynamic Field in South Basin of Shanshan%鄯善县南盆地地下水动力场演化规律研究

    Institute of Scientific and Technical Information of China (English)

    周文

    2014-01-01

    In order to strengthen the groundwater management in Shanshan ,the variation trend of the dynamic field should be studied first .The dynamic characteristics and dynamic field evolution of the groundwater in the south basin of Shanshan County were analyzed according to the data collected from monitoring wells and historical data .The decrement of the ground water resource was calculated with GIS software and by using the spatial operation method and figure overlap method .The results are as follows :it was reduced by 11 .6 × 108 m3 during 1959 - 2004 ;it was reduced by 2 .8 × 108 m3 during 2004 - 2011 ,in total ,it was reduced by 14 .4 × 108 m3 .Simultaneously ,the evolution law of the groundwater in the south basin of Shanshan was revealed :the groundwater’s dynamic field was a pulsing non-stability system before 1960’s ,and a dynamic non-stability expansion system after that .%为了加强鄯善县地下水管理,首先需要研究地下水动力场在人为和自然因素影响下的变化趋势。根据地下水长观井监测数据和历史资料,分析了鄯善县南盆地的地下水动态特征和地下水流场的变化规律,运用 GIS 软件,采用空间运算和叠图等方法,计算了三个时期的地下水储变量:1959-2004年,地下水储量减少11.6×108 m3;2004-2011年,减少了2.8×108 m3,总计减少14.4×108 m3。总结了鄯善县南盆地地下水动力系统的演化规律:20世纪60年代以前,地下水系统为脉动非稳定系统;20世纪60年代以后,为动态非稳定扩张系统。

  15. Sedimentary features, reservoir characteristics and seismic signature of an Aptian incised valley and its lateral equivalent, in the north Ben Nevis field of the Jeanne d`Arc Basin

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, P.J.; Hodder, J.; Harding, S.; Zanussi, L. [Husky Oil, Calgary, AB (Canada); Plint, G. [Western Ontario Univ., London, ON (Canada)

    1998-09-01

    In 1988 three cores from an oil well in the Avalon Formation reservoir zone of the north Ben Nevis field were studied. The field is located within the Jeanne d`Arc Basin on the Grand Banks of Newfoundland. The cores indicated a shallowing-upward clastic sequence of prograding marine shoreface sandstones which end in back barrier lagoon deposits. Recent studies and current ongoing surveys using seismic logs and reservoir characterizations confirmed the original interpretation. An attempt was made to correlate two wells, the M-61 and the P-93. Correlations between the two wells indicate a gross similarity in depositional facies, but core and log analysis indicate major differences, particularly in the upper third of the Avalon Formation where the oil and gas is trapped. Two shallowing-upward shoreface successions are preserved in both wells, but local depositional variations are evident. M-61 showed much better reservoir characteristics than the same unit in P-93. New 3-D seismic data is expected to provide a better resolution of the geology. 1 fig.

  16. Sequence stratigraphy in Rift deposits: an example in the Membro Mucuri (Aptiano) of the Sao Mateus field, Espirito Santo basin, Brazil; Estratigrafia de sequencia em depositos de Rifte: um exemplo no membro Mucuri (Aptiano) do Campo de Sao Mateus, Bacia do Espirito Santo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Guirro, Antonio Celso; Rey, Antonio Cosme Del [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    1998-07-01

    Sao Mateus field is located onshore Espirito Santo basin, Brazil eastern cost. Petroleum accumulations occur in Mucuri Member, Aptian, deposited at the end of basin rift phase. Vertical section of this member records a transition from a continental to a shallow marine environment. Three depositional sequences are recognized. Each sequence consists of lowstand fluvial deposits covered by transgressive deposits with delta estuarine fine grained sediments. The highly transgressive sedimentation pattern makes difficult to discern transgressive to highstand deposits. The reservoirs are fluvial and delta estuarine sandstones, and the seals are transgressive fine grained sediments. Normal faults promoted up-dip closures. (author)

  17. The origin of gas in the Changxing–Feixianguan gas pools in the Longgang gas field in the Sichuan Basin, China

    Directory of Open Access Journals (Sweden)

    Shengfei Qin

    2016-10-01

    Full Text Available In this paper, the origin of natural gas in the formations of the Changxing–Feixianguan within the Longgang gas field was studied in detail using geochemical methods. The gas discovered has a very high dryness coefficient, yet low ethane and other less heavy hydrocarbons content. Apart from a small amount of N2 and CO2 gasses it generally contains H2S. In the field location, the Changxing–Feixianguan formations itself does not have a hydrocarbon generation potential. Nearing the edge of the Kaijiang-Liangping Trough, there developed the Dalong Formation. However, it also has a very low TOC content in the area of the Longgang gas field, and it cannot act as an effective source rock. The geochemistry of natural gas is much different from the gasses generated by the Silurian and Cambrian source rocks. Therefore, it is impossible that the gas in the Longgang gas field is from the Silurian and Cambrian source rocks. Gas reservoirs generally contain bitumen which is considered a product of crude oil cracking. The carbon isotope fractionation between the bitumen and methane is not distinct, and it indicates that the gas is not directly from oil cracking. The carbon of methane and ethane has isotopically less negative value, which is considered to be in a high-overmature coal-formed gas, mainly from the Longtan Formation coal measures. In comparison to the gas from high overmature stage obtained from the Xujiahe coal measure source rock in the Western Sichuan Depression. The methane in the Longgang gas field has abnormal less negative carbon isotopic value. It is due to the superposition of these two factors together: higher evolution of source rocks and mixing of gas degassing from the water. It is not caused by TSR that most researchers believed at present because the methane carbon isotopic values have no relationship with H2S content.

  18. Aptian carbonates of Carmopolis field, Sergipe-Alagoas basin: stratigraphy and depositional model; Carbonatos aptianos do Campo de Carmopolis, bacia de Sergipe-Alagoas: estratigrafia e modelo deposicional

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Carlos Cesar de; Madrucci, Vanessa [PETROBRAS E e P Exploracao, Rio de Janeiro, RJ (Brazil). Geologia Aplicada a Exploracao], Emails: ccaraujo@petrobras.com.br, vanessa.madrucci@petrobras.com.br; Moretti Junior, Paulo Augusto [Petroleo Brasileiro S. A. (PETROBRAS), Rio de Janeiro, RJ (Brazil). Unidade de Negocio de Exploracao e Producao da Bacia de Santos], E-mail: paulo.moretti@petrobras.com.br; Carramal, Nivea Goulart [Petroleo Brasileiro S.A. (PETROBRAS), Vitoria, ES (Brazil). Unidade de Negocio de Exploracao e Producao do Espirito Santo], E-mail: ncarramal@petrobras.com.br; Toczeck, Andre [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil). Unidade de Negocio de Exploracao e Producao da Bacia de Campos], E-mail: toczeck@petrobras.com.br; Almeida, Angela Brito [Petroleo Brasileiro S. A. (PETROBRAS/SEAL), Aracaju, SE (Brazil). Unidade de Negocio de Exploracao e Producao de Sergipe e Alagoas], E-mail: angela.brito@petrobras.com.br

    2009-05-15

    There are occurrences of microbial carbonates in the basal portion of Ibura Mb., Muribeca Fm. Located at the Aracaju High, Late Aptian of Sergipe Basin. These carbonates were deposited over the basement and were described as spatially restricted to the area informally known as the Rosary Inlet. The goal of this paper is to present the depositional carbonate system related to the Ibura Mb., these carbonates were observed in the base section of the cored well. The interval of core description corresponds to the Upper Aptian (P-270 biozone) composed of carbonatic, siliciclastic, evaporitic and hybrid facies. It has been also described early diagenesis related to litoral and evaporitic environment based on rock and thin sections of cuttings. The middle diagenesis is characterized by fracturing, dissolution, prismatic anhydrite, silicification, dolomitization and piritization. Based on core description (facies and facies association) it was performed log facies analysis and it was done the composite logs for all the wells in the area. The microbial carbonate layer is stratigraphically correlated in the entire Aracaju High. A fundamental observation is the thickening trend of the microbial carbonate on the lower areas, with thinning on the higher areas. The Muribeca Fm. (specifically the Ibura and Oiteirinhos members) is interpreted as deposited in a transitional environment with some marine evidences. For the Ibura Mb, at the base of the described core, the depositional environment was interpreted as restricted evaporitic lacustrine lagoon due to: rare presence of fossils, which are limited to some specimens of ostracods; microbial carbonates in the form of microbial mats or carpets; lack of sedimentary structures related to flow and tides; evidences of high salinity and intense evaporation during the deposition in the form of diagenetic anhydrite and evaporite dissolution breccias; presence of nodular and stratified anhydrite layered with carbonaceous mudstone as

  19. Geochemical correlation of oil from the Ayoluengo field to Liassic black shale units in the southwestern Basque-Cantabrian Basin (northern Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Quesada, Santiago; Robles, Sergio [University of the Basque Country, Stratigraphy and Paleontology Dept., Bilbao (Spain); Dorronsoro, Carmen [University of the Basque Country, Geology Dept., Bilbao (Spain); Chaler, Roser; Grimalt, Joan O. [C.I.D.-C.S.I.C., Environmental Chemistry Dept., Barcelona (Spain)

    1997-12-31

    A study of the Liassic sequence in the Basque-Cantabrian Basin has shown the presence of organic-rich (TOC, HI and S{sub 2} up to 8.7%, 760 and 56.5 mg/g, respectively) Pliensbachian-early Toarcian black shales that constitute the only feasible source rock for Ayoluengo oil. The stratigraphical and sedimentological data show that these black shales developed into a major transgressive sequence of hemipelagic Lotharingian-Toarcian facies, which suggests the presence of anoxic or near anoxic bottom water conditions in troughs during their deposition. The {delta}{sup 13}C composition, and a detailed study of the linear, branched, isoprenoid, steroid and hopanoid aliphatic hydrocarbons in these shales, marls and the Ayoluengo oil confirms this hypothesis. Specifically, the {delta}{sup 13}C values of the total solvent extract of the thicker shale (No. 2) and the oil are -29.93 and -29.88``per mille``, respectively; also a close similarity in the relative compositions of steranes and hopanes is observed between these samples. The distributions of these compounds exhibit several distinct features. The steranes in this shale and crude oil are characterized by a depletion of C{sub 28} vs C{sub 27} and C{sub 29} homologues (24 vs 32 and 44%, respectively), which is consistent with the carbon number sterane distributions generally observed among Upper Paleozoic to Liassic rock-sourced oils. Furthermore, hopanes and steranes are characterized by their high relative content of rearranged molecules. Diasteranes (13{beta}(H),17{alpha}(H)- and 13{alpha}(H),17{beta}(H)- series) are the dominant compounds among the steranes and significant amounts of 18{alpha}(H)-17{alpha}methyl-28-norhopanes (C{sub 27}, C{sub 29} and C{sub 30} homologues) and 17{alpha}(H)-15{alpha}-methyl- 27 norhopanes (C{sub 30} homologue) are found in the hopanoid hydrocarbons. Conversely, the proportion of these rearranged molecules in other sediment samples from the same formation decrease with increasing

  20. Modelling the impacts of climate change on wheat yield and field water balance over the Murray-Darling Basin in Australia

    Science.gov (United States)

    Wang, Jing; Wang, Enli; Liu, De Li

    2011-06-01

    The study used a modelling approach to assess the potential impacts of likely climate change and increase in CO2 concentration on the wheat growth and water balance in Murray-Darling Basin in Australia. Impacts of individual changes in temperature, rainfall or CO2 concentration as, well as the 2050 and 2070 climate change scenarios, were analysed. Along an E-W transect, wheat yield at western sites (warmer and drier) was simulated to be more sensitive to temperature increase than that at eastern sites; along the S-N transect, wheat yield at northern warmer sites was simulated to be more sensitive to temperature increase, within 1-3°C temperature increase. Along the E-W and S-N transects, wheat at drier sites would benefit more from elevated [CO2] than at wetter sites, but more sensitive to the decline in rainfall. The increase in temperature only did not have much impact on water balance. Elevated [CO2] increased the drainage in all the sites, whilst rainfall reduction decreased evapotranspiration, runoff and drainage, especially at drier sites. In 2050, wheat yield would increase by 1-10% under all climate change scenarios along the S-N transect, except for the northernmost site (Dalby). Along the E-W transect, the most obvious increase of wheat yields under all climate change scenarios occurred in cooler and wetter eastern sites (Yass and Young), with an average increase rate of 7%. The biggest loss occurred at the driest sites (Griffith and Swan Hill) under A1FI and B2 scenarios, ranging from -5% to -16%. In 2070, there would be an increased risk of yield loss in general, except for the cool and wet sites. Water use efficiency was simulated to increase at most of the study sites under all the climate change scenarios, except for the driest site. Yield variability would increase at drier sites (Ardlethan, Griffith and Swan Hill). Soil types would also impact on the response of wheat yield and water balance to future climate change.

  1. Water quality of groundwater and stream base flow in the Marcellus Shale Gas Field of the Monongahela River Basin, West Virginia, 2011-12

    Science.gov (United States)

    Chambers, Douglas B.; Kozar, Mark D.; Messinger, Terence; Mulder, Michon L.; Pelak, Adam J.; White, Jeremy S.

    2015-01-01

    The Marcellus Shale gas field underlies portions of New York, Pennsylvania, Ohio, Virginia, Maryland, Tennessee, and West Virginia. Development of hydraulic fracturing and horizontal drilling technology led to extensive development of gas from the Marcellus Shale beginning about 2007. The need to identify and monitor changes in water-quality conditions related to development of the Marcellus Shale gas field prompted the U.S. Geological Survey, in cooperation with the West Virginia Department of Environmental Protection, Division of Water and Waste Management, to document water quality for comparison with water quality in samples collected at a future date. The identification of change in water-quality conditions over time is more difficult if baseline water-quality conditions have not been documented.

  2. Simulation of three-dimensional tectonic stress fields and quantitative prediction of tectonic fracture within the Damintun Depression, Liaohe Basin, northeast China

    Science.gov (United States)

    Guo, Peng; Yao, Leihua; Ren, Desheng

    2016-05-01

    Tectonic fractures are important factors that influence oil and natural gas migration and accumulation within "buried hill" reservoirs. To obtain a quantitative forecast of the development and distribution of reservoir fractures in the Damintun Depression, we analyzed the characteristics of regional structural evolution and paleotectonic stress field setting. A reasonable geological model of the research area was built based on an interpretation of the geological structure, a test for rock mechanics, and experiment on acoustic emission. Thereafter, a three-dimensional paleotectonic stress field during the Yanshan movement was simulated by the finite element method. Rock failure criterion and comprehensive evaluation coefficient of fractures were used to determine the quantitative development of fractures and predict zones that are prone to fracture development. Under an intense Yanshan movement, high stress strength is distributed in the south and northeast parts of the study area, where stress is extremely high. The fracture development zones are mainly controlled by the tectonic stress field and typically located in the same areas as those of high maximum principal and shear stresses. The predicted areas with developed fractures are consistent with the wells with high fracture linear density and in locations with high-producing oil and gas wells.

  3. Effects of low-impact-development (LID) practices on streamflow, runoff quantity, and runoff quality in the Ipswich River Basin, Massachusetts-A Summary of field and modeling studies

    Science.gov (United States)

    Zimmerman, Marc J.; Waldron, Marcus C.; Barbaro, Jeffrey R.; Sorenson, Jason R.

    2010-01-01

    Low-impact-development (LID) approaches are intended to create, retain, or restore natural hydrologic and water-quality conditions that may be affected by human alterations. Wide-scale implementation of LID techniques may offer the possibility of improving conditions in river basins, such as the Ipswich River Basin in Massachusetts, that have run dry during the summer because of groundwater withdrawals and drought. From 2005 to 2008, the U.S. Geological Survey, in a cooperative funding agreement with the Massachusetts Department of Conservation and Recreation, monitored small-scale installations of LID enhancements designed to diminish the effects of storm runoff on the quantity and quality of surface water and groundwater. Funding for the studies also was contributed by the U.S. Environmental Protection Agency's Targeted Watersheds Grant Program through a financial assistance agreement with Massachusetts Department of Conservation and Recreation. The monitoring studies examined the effects of * replacing an impervious parking-lot surface with a porous surface on groundwater quality, * installing rain gardens and porous pavement in a neighborhood of 3 acres on the quantity and quality of stormwater runoff, and * installing a 3,000-ft2 (square-foot) green roof on the quantity and quality of rainfall-generated roof runoff. In addition to these small-scale installations, the U.S. Geological Survey's Ipswich River Basin model was used to simulate the basin-wide effects on streamflow of several changes: broad-scale implementation of LID techniques, reduced water-supply withdrawals, and water-conservation measures. Water-supply and conservation scenarios for application in model simulations were developed with the assistance of two technical advisory committees that included representatives of State agencies responsible for water resources, the U.S. Environmental Protection Agency, the U.S. Geological Survey, water suppliers, and non-governmental organizations. From June

  4. Actual extension of sinkholes: Considerations about geophysical, geomorphological, and field inspection techniques in urban planning projects in the Ebro basin (NE Spain)

    Science.gov (United States)

    Pueyo Anchuela, Ó.; Pocoví Juan, A.; Casas-Sainz, A. M.; Ansón-López, D.; Gil-Garbi, H.

    2013-05-01

    Aerial photographs, historical cartographies, and field inspection are useful tools in urban planning design on mantled karst because they permit a wide time interval to be analyzed. In the case of Zaragoza city, several works have confirmed the interest of these approaches in configuring the urban planning code and therefore represent a promising technique. Nevertheless, some caveats should be taken into account when using this kind of information. A detailed analysis is presented comparing (in a case study from the surroundings of Zaragoza) geomorphological, historical analysis, and field inspection with geophysical data. Field inspection in a noncultivated area permits the constraint of the presence of karst indicators below the geomorphological resolution of aerial photographs and shows results consistent with geophysical surveys. The studied case shows an inner zone coinciding with the sinkhole mapped from aerial photographs that correlates with changes in the position of the substratum and changes in thickness of alluvial sediments. The integrated analysis permits us to define an external subsidence ring around the geomorphological sinkhole whose surface is twice the size of the inner zone. This outer ring is indicated by geometrical changes in GPR profiles, increases of thickness of the conductive shallower unit toward the collapse, and small collapses on marginal cracks. These results support the higher extension of karst hazards linked to sinkholes with respect to their geomorphological expression and the needed detailed analysis to constrain the real sinkhole size or the use of security radii surrounding this surficial evidence when geomorphological data is used for the hazard analyses or the urban planning at karstic zones.

  5. Increased oil production and reserves from improved completion techniques in the Bluebell Field, Uinta Basin, Utah. Annual report, October 1, 1996--September 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Deo, M.D.; Morgan, C.D.

    1998-05-01

    Wells in the Bluebell field are typically completed by perforating 40 or more beds over 1,000 to 3,000 vertical ft, them stimulating the entire interval with hydrochloric acid. This technique is often referred to as the shot gun completion. The shot-gun technique is believed to leave many potentially productive beds damaged and/or untreated, while allowing water-bearing and low-pressure (thief) zones to communicate with the wellbore. A two-year characterization study involved detailed examination of outcrop, core, well logs, surface and subsurface fractures, produced oil-field waters, engineering parameters of the two demonstration wells, and analysis of past completion techniques and effectiveness. The study was intended to improve the geologic characterization of the producing formations and thereby develop completion techniques specific to the producing beds or facies instead of a shot gun approach to stimulating all the beds. The characterization did not identify predictable-facies or predictable-fracture trends within the vertical stratigraphic column as originally hoped. Advanced logging techniques can identify productive beds in individual wells. A field-demonstration program was developed to use cased-hole advanced logging techniques in two wells and recompletion the wells at two different scales based on the logging. The first well was going to be completed at the interval scale using a multiple stage completion technique (about 500 ft per stage). The second well will be recompleted at the bed-scale using bridge plug and packer to isolate three or more beds for stimulation. These recompletion will show which logs are most effective in identifying productive beds and what scale of completion is most cost effective. The third demonstration will be the logging and completion of a new well using the logs and completion scale or technique most effective in the previous demonstrations.

  6. Submarine Landslides in Arctic Sedimentation: Canada Basin

    Science.gov (United States)

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Lebedova-Ivanova, N; Chapman, C.

    2016-01-01

    Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of development, Canada Basin is geomorphologically confined with stable oceanographic structure, resulting in restricted depositional/reworking processes. The sedimentary record, therefore, underscores the significance of mass-transport processes in providing sediments to oceanic abyssal plains as few other basins are able to do.

  7. 柴达木盆地大浪滩130ka BP以来的孢粉组合与古气候%Sporo-pollen assemblage and palaeoenvironment since 130 ka BP in Dalangtan Lake of Qaidarn Basin

    Institute of Scientific and Technical Information of China (English)

    侯献华; 郑绵平; 杨振京; 杨庆华; 毕志伟

    2011-01-01

    This paper obtained the data of the cores based on U-series age from ZK02 borehole at ridge of Dalangtan in the western Qaidam basin, where 34 samples from the sludge containing gypsum silt were selected of select for 130 ka BP (90.5 m and above) and the pollen analysis was done. Based on the pollen characteristics, the assemblage of the pollen from the bottom upwards can be divided into six zones to analyze the ancient vegetation succession in the last interglacial (130 ka BP) state in this area. The results showed as follows: in the period of 130 ka BP (the last interglacial period), the vegetation in the western Qaidam basin obviously changed compared with the very significant environment. Overall, the spruce, fir and pine trees consisted of some cold temperate coniferous forest had expanded for five times to the surrounded Zhongshan area, and even extends towards the basin. But thegrass of Gramineae, Compositae, Artemisia as the main component occupied the basin, which showed the climate that was mild climate controlled by the summer monsoon flow from the East Asia to the West, while vegetation flourished, the enhanced soil expanded, water being desalinized, the lake larger in the interstadial period, particularly that in the first pollen assemblage I ( 130 -92 ka BP) and the pollen assemblage IV (56.2 -49 ka BP) in the duration of sedimentation when the plant diversity increased. In addition to the grassland vegetation in the basin, on the wetlands around the lake the plant was growing quite flonrishing, which demonstrated that the two periods were the most enhanced summer monsoon circulation with more adequate rainfall and the forest expanding fast in the mountains. The river flow was incresing and salt lake became desaltinized. The emergent grasses were growing at the edge of the marsh in the lake area. In particular in 49 ka BP ago or so, coniferous forest was growing associated with mountain cedar. Thus it suggested that the place was affected by the

  8. Agulha (Potiguar Basin): an old field with exploitation new ideas; Agulha (Bacia Potiguar): um velho campo com novas ideias de explotacao

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Diogenes C. de; Rodrigues, Luis G. [PETROBRAS, Natal, RN (Brazil)

    2004-07-01

    The integrated reservoir analysis of the Agulha field has led to several alternative actions to improve oil recovery, despite the fact that the field has already produced more than 45% of the currently mapped oil in place in nearly three decades. Studies were carried out taking into account not only elements of production behavior, but also the geologic aspects of the productive zones. Among various proposed actions, the following can be outlined: change of the water injection quota; workover for improvement of the swept efficiency; modification of the production schedule of some wells; improvement on the efficiency of the gas lift system. Additionally, the possibility that some wells be systematically producing from some hydrocarbon accumulations in volcanic rocks (not classified as reservoir yet), which is feeding traditional turbidities reservoirs is also investigated. The use of geochemical saturation, image and cement logs may lead to identify new oil producing horizons, including non-conventional reservoirs. In order to support new ideas on reservoir geometry and subsequent modeling, a new seismic acquisition is proposed. (author)

  9. 柴达木盆地东部三湖地区四系米兰柯维奇旋回分析%Analysis of milankovitch cycles of quaternary in sanhu area ,eastern qaidam basin

    Institute of Scientific and Technical Information of China (English)

    王永军; 郭泽清; 刘卫红; 徐小林; 曾富英

    2007-01-01

    自然伽马曲线包含丰富的地质信息,能够很好地反映由气候变化引起的地层旋回.本文采用频谱分析对柴达木盆地三湖地区第四系自然伽马测井曲线进行了系统分析.作为频谱分析方法之一的快速傅里叶变换能够将自然伽马曲线从时间(深度)域转换为频率域,然后分析每一个峰值频率的波长及其相互之间的比率关系,寻找那些波长比率与米兰柯维奇周期比率相同或相似的频率,从而捕获高频旋回信息.研究结果表明第四系地层中很好地保存了高频的米兰柯维奇旋回,这样的沉积旋回主要由地球轨道的周期性变化而导致的古气候变化引起的.偏心率周期引起的地层旋回厚度变化范围在92.00~115.00 m之间,黄赤交角引起的地层旋回厚度变化范围在24.55~63.43 m之间,岁差引起的地层旋回厚度变化范围在16.8~26.35 m 之间.黄赤交角和岁差是影响该区米兰柯维奇旋回的主要因素,其中岁差的影响最大,而偏心率的影响最小.

  10. Magnetostratigraphy of Liang ZK05 Borehole in Dalangtan, Qaidam Basin%柴达木盆地大浪滩梁ZK05钻孔的磁性地层研究

    Institute of Scientific and Technical Information of China (English)

    施林峰; 郑绵平; 李金锁; 王有德; 侯献华; 马妮娜

    2010-01-01

    本文展示了柴达木盆地西北地区大浪滩盆地梁ZK05钻孔上部330m岩芯的最新磁性地层结果.梁ZK05钻孔的磁极性序列记录了4个正极性亚时,分别对应于布容期、Jaramillo、Cobb Mountain和Olduvai.磁极性序列底部未出现Reunion亚时,其年代应小于2128ka,B/M界限深度位于94m.根据钻孔的平均沉积速率,我们推算出钻孔最顶部的年代为111ka,钻孔在330m深度的年代为2046ka.由此可知,钻孔330m以下的卵砾石层沉积的结束年代为2Ma,代表阿尔金山的这次强烈隆升应早于2Ma,与青藏运动B幕相当,其启始时间为2.6Ma,结束时间大致为2Ma.另外,梁ZK05钻孔记录了3次极性漂移事件,位于51~58m、207.5~212m和249~252m,分别对应于Calabrian Ridge 2(515~525ka)、Gardar(1465~1485ka)和Gilsa(1567~1575ka).我们在沈振枢等人(1993的8个钻孔磁性柱基础上,加上梁ZK05钻孔和ZK02钻孔的磁极性序列,辅以最新的国际标准磁极性年表,建立了柴达木盆地最新的磁性地层年代框架.

  11. The effect of an oil drilling operation on the trace metal concentrations in offshore bottom sediments of the Campos Basin oil field, SE Brazil.

    Science.gov (United States)

    Rezende, C E; Lacerda, L D; Ovalle, A R C; Souza, C M M; Gobo, A A R; Santos, D O

    2002-07-01

    The concentrations of Al, Fe, Mn, Zn, Cu, Pb, Ni, Cr, Ba, V, Sn and As in offshore bottom sediments from the Bacia de Campos oil field, SE Brazil, were measured at the beginning and at 7 months after completion of the drilling operation. Concentrations of Al, Fe, Ba, Cr, Ni and Zn were significantly higher closer to the drilling site compared to stations far from the site. Average concentrations of Al, Cu, and in particular of Ni, were significantly higher at the end of the drilling operation than at the beginning. Comparison between drilling area sediments with control sediments of the continental platform, however, showed no significant difference in trace metal concentrations. Under the operation conditions of this drilling event, the results show that while changes in some trace metal concentrations do occur during drilling operations, they are not significantly large to be distinguished from natural variability of the local background concentrations.

  12. Physical simulation of gas reservoir formation in the Liwan 3-1 deep-water gas field in the Baiyun sag, Pearl River Mouth Basin

    Directory of Open Access Journals (Sweden)

    Gang Gao

    2015-01-01

    Full Text Available To figure out the process and controlling factors of gas reservoir formation in deep-waters, based on an analysis of geological features, source of natural gas and process of reservoir formation in the Liwan 3-1 gas field, physical simulation experiment of the gas reservoir formation process has been performed, consequently, pattern and features of gas reservoir formation in the Baiyun sag has been found out. The results of the experiment show that: ① the formation of the Liwan 3-1 faulted anticline gas field is closely related to the longstanding active large faults, where natural gas is composed of a high proportion of hydrocarbons, a small amount of non-hydrocarbons, and the wet gas generated during highly mature stage shows obvious vertical migration signs; ② liquid hydrocarbons associated with natural gas there are derived from source rock of the Enping & Zhuhai Formation, whereas natural gas comes mainly from source rock of the Enping Formation, and source rock of the Wenchang Formation made a little contribution during the early Eocene period as well; ③ although there was gas migration and accumulation, yet most of the natural gas mainly scattered and dispersed due to the stronger activity of faults in the early period; later as fault activity gradually weakened, gas started to accumulate into reservoirs in the Baiyun sag; ④ there is stronger vertical migration of oil and gas than lateral migration, and the places where fault links effective source rocks with reservoirs are most likely for gas accumulation; ⑤ effective temporal-spatial coupling of source-fault-reservoir in late stage is the key to gas reservoir formation in the Baiyun sag; ⑥ the nearer the distance from a trap to a large-scale fault and hydrocarbon source kitchen, the more likely gas may accumulate in the trap in late stage, therefore gas accumulation efficiency is much lower for the traps which are far away from large-scale faults and hydrocarbon source

  13. Oil production in the Orinoco basin

    Energy Technology Data Exchange (ETDEWEB)

    Borregales, C.J.

    1980-02-01

    With an extension of 42,000 sq km, the Orinoco basin is one of the largest petroliferous zones in the world which contains high viscosity and low API gravity crude. Results from production tests performed in the central and southern parts of the basin indicate that its productive potential is similar to that in Morichal, Pilon and Jobo fields, and reveals that the heaviest oil existing in the Orinoco basin could be economically exploited by conventional methods of primary oil recovery. It is estimated that the oil recovery could be 5% of the total oil-in-place by using primary recovery methods, 8% by using alternate steam injection, and 20% by secondary recovery methods (continuous steam injection). However, if the compaction phenomenon takes place, an estimate of 5% to 15% additional oil recovery could be possible. Geology, fluid properties, results from production tests, and recovery methods in the Orinoco basin are presented.

  14. Neogene deformation and its implications for the structural framework of the oil fields in the Icapui-Ponta Grossa (CE) region, onshore Potiguar Basin, Brazil; Deformacao neogena e suas implicacoes na estruturacao dos campos de petroleo na regiao de Icapui-Ponta Grossa (CE), Bacia Potiguar emersa

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Debora do Carmo [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Geodinamica e Geofisica]. E-mail: debora@geologia.ufrn.br; Sa, Emanuel Ferraz Jardim de; Antunes, Alex Francisco [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Geologia

    2008-06-15

    In coastal cliffs at the western portion of the Potiguar Basin (so-called Aracati Platform), the Barreiras Formation, of miocene age, displays structures pointing to high strain deformation. Detailed mapping of faults and folds geometry in the Barreiras Formation leads to recognition of extensional structures (at Ponta Grossa village) and contractional oblique structures (Vila Nova, next to Icapui town), both of them related to a trans current system bearing NE (at these locations) and NW trends (Afonso Bezerra Fault, in the central portion of the basin). These data point to a neo gene stress field which generated faults, folds and hydro plastics structures, including SL fabrics and shear zones, as well as reactivated older structures in the underlying neocretaceous sedimentary section. Reinterpretation of seismic sections from this region and other geological data at several places in the Potiguar Basin outline structures which are correlated (in style and kinematic regime) throughout the siliciclastic rocks of the Acu Formation, limestones of the Jandaira Formation and younger basalts of the Macau Formation, whose age straddles the Oligocene-Miocene boundary. This structural framework recognized at the surface has to be compatible with subsurface deformation as observed in seismic sections, which includes pulses/events of older, Neocretaceous to Paleocene age. This model has important implications as regards the structure (geometry, kinematics, age of traps) of oil reservoirs (especially the sandstones of the Acu Formation, in the Fazenda Belem Oil Field) and the processes of migration and hydrocarbon entrapment at this region of the Potiguar Basin. (author)

  15. Patterns of stress field orientations, structures, basement structural heritage and tectonic evolution of the Camamu and Reconcavo South Basins, Palm Tree's coastline, Bahia, Brazil; Padroes de orientacao dos campos de tensao, estruturas, heranca do embasamento e evolucao tectonica das bacias de Camamu e porcao sul do Reconcavo, Costa do Dende, Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Correa-Gomes, Luiz Cesar [Centro Federal de Educacao Tecnologica da Bahia, Salvador, BA (Brazil). Dept. de Ciencias Aplicadas]. E-mails: gomes@cefetba.br, lccgomes@ufba.br; Dominguez, Jose Maria Landim; Barbosa, Johildo Salomao Figueiredo; Silva, Idney Cavalcanti da; Pinto, Moises Vieira [Universidade Federal da Bahia (UFBA), Campus de Ondina, Salvador, BA (Brazil). Inst. de Geociencias. Dept. de Geologia]. E-mails: jose_landim@uol.com.br; johildo@cpgg.ufba.br; idney25@ig.com.br

    2005-12-15

    The Camamu and Reconcavo South Basins are located near the passive continental margin of the Bahia State, Brazil, and have high potential for hydrocarbon exploration. In these basins and surrounding basement, brittle and ductile structures were studied, which resulted in 3D stress field orientations by use of inversion methods. From this study, the following results are relevant: important control of the basement structural heritage on the basin formation and evolution; local strike-inversion of {sigma}{sub 1} and {sigma}{sub 3} orientations in transtensive settings; vertical {sigma}{sub 1} typical of extensional regime precedes sub horizontal {sigma}{sub 1} of transtensive one; in relation to basin's long axes, at least four main horizontal {sigma}{sub 1} orientations were obtained, involving parallel, orthogonal and two diagonal sets. This could be related to: parallel and orthogonal flexural stress due to the sedimentary load, local elastic rebound of fault blocks, stress channeling, density contrasts between oceanic and continental crusts and ridge pull of the adjacent oceanic plate; diagonals, due to a combination of first order regional and second order local stress fields. This suggest that the continental margin of the Bahia State evolves from a typical passive into a transtensive margin, with transpressive regime that have been observed in some places, in a classical evolution of the Wilson Cycle. (author)

  16. Control Effect of Evolution of North Sea Basin on Formation of Giant Oil-Gas Fields%北海盆地形成演化对大油气田的控制作用

    Institute of Scientific and Technical Information of China (English)

    刘政; 何登发; 温志新; 李涤

    2012-01-01

    The North Sea basin underwent eight orogenic stages and gave rise to the frameworks that the metamorphic basement was formed in Caledonian stage; Pangaea following Paleo-Tethys closure shaped in Hercynian, and the coal-measure source rock deposited in the south- em North Sea basin; southern and northern North Sea basin continued subsidence in intra-craton stage, with early arid .climate and late large-scale marine transgression, forming favorable reserv0ir-cap rocks assemblage in south of it; regional extension environment gave rise to Viking, Central and Moray Firth grabens and troughs in rifting stage; uplifting of central North Sea basin e0mpanied with many a volca- nic activity in thermal uplift stage, providing large amount of provenances for development of the northern reservoir rocks; central dome sub- sidence in major rifting stage followed by being submerged, causing premium source rocks development in northern of it; relatively stable sedimentary environment in late rifting state allowed large amount of chalks to develop in the central and deposit marls in the northern, shaping regional cap rocks in the northern of this basin; and in post-rifting stage, Norway-Greenland Sea separation occurred, and sustained and stable deposition under previous structural framework provided favorable environment for oil and gas preservation. Finally, these result- ed in framework as giant gas fields dominantly distributed in the southern and giant oil fields in the northern, and contemporarily, "upper source-lower reservoir" and "lower source-upper reservoir" characteristics were found in Viking graben and Central graben, respectively.%分析了北海盆地的形成演化对大油气田形成的控制作用。研究认为,北海盆地经历了8个构造演化期,加里东运动期形成了主要变质岩基底;海西运动导致古特提斯洋关闭,形成联合古陆,同时沉积了盆地南部重要的煤系烃源岩;陆内克拉通期盆地南、

  17. Classification and features of single-well flow units in a carbonate reservoir - Taking the NT oil field at the eastern edge of Pre-Caspian Basin as an example

    Science.gov (United States)

    Fan, Zifei; Wang, Shuqin; Liu, Lingli; Li, Jianxin; Zhao, Wenqi; Sun, Meng

    2017-01-01

    Identifying the carbonate reservoirs has always been a challenge to geological exploration, while reasonable classification of flow units is the bottleneck in this exploitation. While taking the NT oil field at the eastern edge of Pre-Caspian Basin as an example, this paper proposes the classification of flow units into five categories based on previous flow-unit classification theory and actual oilfield features by using the pore throat radius at the mercury injection saturation of 35% as the main judging criterion. In this paper, the features of various flow units have also been analyzed. The type-I flow units, mainly found in dolomite and algal reef limestone reservoirs, have the highest production capacity. Given the existence of corrosion and dolomitization, they are mainly fracture-cave composite reservoirs or fracture pore reservoirs. As far as the type-I flow units are concerned, the flow index is > 1.42 for KT-I stratum and > 1.55 for KT-II stratum. The production capacity and reservoir quality of type-II-IV flow units would decline in turn. The type-V flow units are argillaceous limestone, with a very low production capacity and a flow index being 0.01-0.05 for KT-I and 0.03-0.05 for KT-II.

  18. Daily Variation of Natural Emission of Methane to the Atmosphere and Source Identification in the Luntai Fault Region of the Yakela Condensed Oil/Gas Field in the Tarim Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The static flux chamber method was applied to study natural emissions of methane to the atmosphere in the Luntai fault region of Yakela Condensed Oil/Gas Field in the Tarim Basin,Xinjiang Municipality, northwestern China. Using an online method, which couples together a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS), 13C/12C ratios of methane in flux chambers were measured and showed that methane gases are liable to migrate from deep oil/gas reservoirs to the surface through fault regions and that a part of the migrated methane, which remains unoxidized can be emitted into the atmosphere. Methane emission rates were found to be highest in the mornings, lowest in the afternoons and then increase gradually in the evenings. Methane emission rates varied dramatically in different locations in the fault region. The concentrations increased gradually, which reveals that methane released from the fault region might come from thermogenic methane of the deep condensed oil/gas reservoir.

  19. Reconstruction of the diagenesis of the fluvial-lacustrine- deltaic sandstones and its influence on the reservoir quality evolution-- Evidence from Jurassic and Triassic sandstones, Yanchang Oil Field, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The reservoir quality of Jurassic and Triassic fluvial and lacustrine-deltaic sandstones of the Yanchang Oil Field in the Ordos Basin is strongly influenced by the burial history and facies-related diagenetic events. The fluvial sandstones have a higher average porosity (14.8%) and a higher permeability (12.7×10?3 ?m2) than those of the deltaic sandstones (9.8% and 5.8 ×10?3 ?m2, respectively). The burial compaction, which resulted in 15% and 20% porosity loss for Jurassic and Triassic sandstones, respectively, is the main factor causing the loss of porosity both for the Jurassic and Triassic sandstones. Among the cements, carbonate is the main one that reduced the reservoir quality of the sandstones. The organic acidic fluid derived from organic matter in the source rocks, the inorganic fluid from rock-water reaction during the late diagenesis, and meteoric waters during the epidiagenesis resulted in the formation of dissolution porosity, which is the main reason for the enhancement of reservoir-quality.

  20. Modeling and identification of new complementary development opportunities in a Campos Basin offshore giant field; Modelagem e identificacao de novas oportunidades de desenvolvimento complementar de um campo gigante na Bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Jose Adilson T.; Steagall, Daniel E.; Lorenzatto, Rudimar Andreis [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The objective of this paper is to present the methodology that has been used for the complementary development of the giant Marlin oil field in the Campos Basin, with the study of the opportunities of new wells and application of new technologies for the enhancement of production, recovery factor and the gain of reserves. This methodology is applied integrating geophysics, geology, engineering, planning and operation, containing: identification of the non drained areas, positioning of new locations, risk analysis, reduction risk analysis actions, production estimation, attractive location selection; conceptual well project with location of the well head, submarine layout, drilling program, multiphase flow curves; drilling schedule, completion, and production commencement; production forecasting with flux simulation using operational reality of the oil, gas, and water treatment production capacity; wells substitution and deviation criteria; project critical resources and preliminary economical evaluation including project risk. The obtained results were the optimization of the project portfolio of new wells considering the identification of new opportunities, schedule and entrance order of wells, helping also in the acquisitions of new data for reservoir risk reduction before project implementation. (author)

  1. Po-Basin Atmospheric Composition during the Pegasos Field Campaign (summer 2012): Evaluation of ninfa/aodeM Simulation with In-Situ e Remote Sensing Observations

    Science.gov (United States)

    Landi, Tony C.; Bonafe, Giovanni; Stortini, Michele; Minguzzi, Enrico; Cristofanelli, Paolo; Marinoni, Angela; Giulianelli, Lara; Sandrini, Silvia; Gilardoni, Stefania; Rinaldi, Matteo; Ricciardelli, Isabella

    2014-05-01

    Within the EU project PEGASOS one of three field campaigns took place in the Po Valley during the summer of 2012. Photochemistry, particle formation, and particle properties related to diurnal evolution of the PBL were investigated through both in-situ and airborne measurements on board a Zeppelin NT air ship. In addition, 3-D air quality modeling systems were implemented over the Po valley for the summer 2012 to better characterize the atmospheric conditions, in terms of meteorological parameters and chemical composition. In this work, we present a comparison between atmospheric composition simulations carried out by the modeling system NINFA/AODEM with measurements performed during the PEGASOS field campaign for the period 13 June - 12 July 2012. NINFA (Stortini et al., 2007) is based on the chemical transport model CHIMERE (Bessagnet et al., 2008), driven by COSMO-I7, the meteorological Italian Limited Area Model, (Steppeler et al., 2003). Boundary conditions are provided by Prev'air data (www.prevair.org), and emission data input are based on regional, national and European inventory. Besides, a post-processing tool for aerosol optical properties calculation, called AODEM (Landi T. C. 2013) was implemented. Thus, predictions of Aerosol Optical Depth and aerosol extinction coefficient were also used for model comparison to vertical-resolved observations. For this experiment, NINFA/AODEM has been also evaluated by using measurements of size-segregated aerosol samples, number particles concentration and aerosol optical properties collected on hourly basis at the 3 different sampling sites representative of urban background (Bologna), rural background (San Pietro Capofiume) and remote high altitude station (Monte Cimone 2165 ma.s.l.). ). In addition, we focused on new particles formations events and long range transports from Northern Africa observed during the field campaign. References Bessagnet, Bertrand, Laurent Menut, Gabriele Curci, Alma Hodzic, Bruno

  2. Effects of sand-shale anisotropy on amplitude variation with angle (AVA) modelling: The Sawan gas field (Pakistan) as a key case-study for South Asia's sedimentary basins

    Science.gov (United States)

    Anwer, Hafiz Mubbasher; Alves, Tiago M.; Ali, Aamir; Zubair

    2017-10-01

    Amplitude variation with angle (AVA) is a technique widely used in the characterisation of hydrocarbon reservoirs and assumes the Earth's crust to be an isotropic medium. Yet, anisotropy is ubiquitous in stratigraphic sequences and has first-order effects on seismic AVA responses when investigating subsurface prospects. This work analyses the effects of anisotropic strata on AVA responses using the Lower Goru Formation, middle Indus basin (Pakistan) as a case study. In the study area, shale intervals are interbedded with reservoir sands of the Sawan gas field. Shales in this field form laminae or are dispersed within reservoir sands, making the Lower Goru Formation an example of a vertically transversely isotropic (VTI) medium. In this work, we calculate the effective (saturated) mechanical properties of the Lower Goru Formation based on rock physics templates; the Backus (1962) average typically designed for layered media, combined with the empirical relations of Brown and Korringa (1975) and Wood (1955). The input data used in our rock physics modelling is based on detailed petrophysical analyses of well data. Using the saturated effective mechanical properties of the Lower Goru Formation, we generate angle-dependent reflection coefficient curves (and seismic AVA responses) based on exact and approximate solutions, for both isotropic and anisotropic reservoir scenarios. Our results suggest that the effects of lithological anisotropy are more pronounced in places with thick shale beds within reservoir sands. Conversely, angle-dependent reflection curves, and seismic AVA responses based on isotropic or anisotropic cases, give similar solutions in the presence of thin shale beds. As a corollary of this work, we present a Bayesian inversion method for the estimation of porosity in VTI media.

  3. Fault features and enrichment laws of narrow-channel distal tight sandstone gas reservoirs: A case study of the Jurassic Shaximiao Fm gas reservoir in the Zhongjiang Gas Field, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Zhongping Li

    2016-11-01

    Full Text Available The Jurassic Shaximiao Fm gas reservoir in the Zhongjiang Gas Field, Sichuan Basin, is the main base of Sinopec Southwest Oil & Gas Company for gas reserves and production increase during the 12th Five-Year Plan. However, its natural gas exploration and development process was restricted severely, since the exploration wells cannot be deployed effectively in this area based on the previous gas accumulation and enrichment pattern of “hydrocarbon source fault + channel sand body + local structure”. In this paper, the regional fault features and the gas accumulation and enrichment laws were discussed by analyzing the factors like fault evolution, fault elements, fault-sand body configuration (the configuration relationship between hydrocarbon source faults and channel sand bodies, trap types, and reservoir anatomy. It is concluded that the accumulation and enrichment of the Shaximiao Fm gas reservoir in this area is controlled by three factors, i.e., hydrocarbon source, sedimentary facies and structural position. It follows the accumulation laws of source controlling region, facies controlling zone and position controlling reservoir, which means deep source and shallow accumulation, fault-sand body conductivity, multiphase channel, differential accumulation, adjusted enrichment and gas enrichment at sweet spots. A good configuration relationship between hydrocarbon source faults and channel sand bodies is the basic condition for the formation of gas reservoirs. Natural gas accumulated preferentially in the structures or positions with good fault-sand body configuration. Gas reservoirs can also be formed in the monoclinal structures which were formed after the late structural adjustment. In the zones supported by multiple faults or near the crush zones, no gas accumulation occurs, but water is dominantly produced. The gas-bearing potential is low in the area with undeveloped faults or being 30 km away from the hydrocarbon source faults. So

  4. Modern dust aerosol availability in northwestern China.

    Science.gov (United States)

    Wang, Xunming; Cheng, Hong; Che, Huizheng; Sun, Jimin; Lu, Huayu; Qiang, Mingrui; Hua, Ting; Zhu, Bingqi; Li, Hui; Ma, Wenyong; Lang, Lili; Jiao, Linlin; Li, Danfeng

    2017-08-18

    The sources of modern dust aerosols and their emission magnitudes are fundamental for linking dust with climate and environment. Using field sample data, wind tunnel experiments and statistical analysis, we determined the contributions of wadis, gobi (stony desert), lakebeds, riverbeds, and interdunes to modern dust aerosol availability in the three important potential dust sources including the Tarim Basin, Qaidam Basin, and Ala Shan Plateau of China. The results show that riverbeds are the dominant landscape for modern dust aerosol availabilities in the Qaidam Basin, while wadis, gobi, and interdunes are the main landscapes over the Ala Shan Plateau and Tarim Basin. The Ala Shan Plateau and Tarim Basin are potential dust sources in northwestern China, while the Qaidam Basin is not a major source of the modern dust aerosols nowadays, and it is not acting in a significant way to the Loess Plateau presently. Moreover, most of modern dust aerosol emissions from China originated from aeolian processes with low intensities rather than from major dust events.

  5. 准噶尔盆地春晖油田石炭系火山岩储层控制因素分析%Controlling factors of the Carboniferous volcanic reservoirs in the Chunhui Oil Field, Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    董臣强

    2014-01-01

    春晖油田石炭系火山岩地层中,油气富集程度与储层发育程度呈正相关关系。研究认为,储层的发育与分布主要受岩相、岩性和构造运动的控制。岩相控制岩性,岩性控制储集空间组合类型,溢流相和火山沉积相围绕爆发相具有环带状分布特点,从火山角砾岩→玄武岩、安山岩→凝灰岩,储集性能逐渐变差;构造运动则控制裂缝的发育及溶蚀作用,断层周边微裂缝发育,沿着微裂缝则溶蚀作用增强,次生孔隙发育。%The Chunhui Oil Field in the Junggar Basin lies in the western part of the Halaalate Mountain tectonic zone, in which the Carboniferous volcanic strata consist dominantly of the volcanic rocks such as tuff, andesite, basalt and volcanic breccias. There is a positive correlation between the hydrocarbon enrichment and reservoir development in the Carboniferous volcanic reservoir rocks from the Chunhui Oil Field. The distribution and development of the volcanic reservoir rocks are primarily controlled by lithofacies, lithology and tectonism. On the whole, the lithofacies may exercise a major control on lithology of the volcanic reservoir rocks, which, in turn, may control the reservoir spaces types. The volcanic rocks in the Chunhui Oil Field exhibit a trend of the girdle pattern of lithofacies changes from the explosive facies through the effusive facies to the volcano-sedimentary facies. The reservoir capacity is gradually getting poor and poor from volcanic breccias to basalt and andesite and finally to tuff. The tectonism is also believed to be a major control on the fissure development and dissolution. The structural stress may give rise to the formation of the cracks or fissures in the brittle rocks, which may greatly improve the reservoir spaces of the Carboniferous volcanic reservoir rocks in the study area.

  6. Performance characterisation of a stormwater treatment bioretention basin.

    Science.gov (United States)

    Mangangka, Isri R; Liu, An; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2015-03-01

    Treatment performance of bioretention basins closely depends on hydrologic and hydraulic factors such as rainfall characteristics and inflow and outflow discharges. An in-depth understanding of the influence of these factors on water quality treatment performance can provide important guidance for effective bioretention basin design. In this paper, hydraulic and hydrologic factors impacting pollutant removal by a bioretention basin were assessed under field conditions. Outcomes of the study confirmed that the antecedent dry period plays an important role in influencing treatment performance. A relatively long antecedent dry period reduces nitrite and ammonium concentrations while increasing the nitrate concentration, which confirms that nitrification occurs within the bioretention basin. Additionally, pollutant leaching influences bioretention basin treatment performance, reducing the nutrients removal efficiency, which was lower for high rainfall events. These outcomes will contribute to a greater understanding of the treatment performance of bioretention basins, assisting in the design, operation and maintenance of these systems.

  7. Geothermal resources of California sedimentary basins

    Science.gov (United States)

    Williams, C.F.; Grubb, F.V.; Galanis, S.P.

    2004-01-01

    The 2004 Department of Energy (DOE) Strategic Plan for geothermal energy calls for expanding the geothermal resource base of the United States to 40,000 MW of electric power generating potential. This will require advances in technologies for exploiting unconventional geothermal resources, including Enhanced Geothermal Systems (EGS) and geopressured geothermal. An investigation of thermal conditions in California sedimentary basins through new temperature and heat flow measurements reveals significant geothermal potential in some areas. In many of the basins, the combined cooling effects of recent tectonic and sedimentary processes result in relatively low (geothermal gradients. For example, temperatures in the upper 3 km of San Joaquin, Sacramento and Ventura basins are typically less than 125??C and do not reach 200??c by 5 km. By contrast, in the Cuyama, Santa Maria and western Los Angeles basins, heat flow exceeds 80 mW/m2 and temperatures near or above 200??C occur at 4 to 5 km depth, which represents thermal conditions equivalent to or hotter than those encountered at the Soultz EGS geothermal site in Europe. Although the extractable geothermal energy contained in these basins is not large relative to the major California producing geothermal fields at The Geysers or Salton Sea, the collocation in the Los Angeles basin of a substantial petroleum extraction infrastructure and a major metropolitan area may make it attractive for eventual geothermal development as EGS technology matures.

  8. Formation Conditions of Panhandle-Hugoton Gas Field in North America and Puguang Gas Field in Sichuan Basin of China: Contrast and Revelation%潘汉得——胡果顿与普光气田形成条件对比及启示

    Institute of Scientific and Technical Information of China (English)

    徐思煌; 曹婷婷; W.L.Watney

    2012-01-01

    Panhandle-Hugoton gas field in North America and Puguang gas field in Sichuan basin of China are all giant marine carbonate gas fields in the world. It is suggested from comparison and analysis of the geological setting, pool-forming condition and process of these two gas fields that Panhandle-Hugoton and Puguang gas fields are all characterized by multiple source rocks, good reservoir rocks with mid- dle-high porosity and permeability, and the gas pools suffered multistage reformation and stabilization controlled by late tectonization, and gypsum and salt cap rocks. The most difference between them is the development degree of their cap rocks. The thickness and continuity of regional gypsum and salt cap rock in Panhandle-Hugoton gas field are clearly superior to those in Puguang gas field, showing that the seal- ing and preserving condition are the key factors for the formation of giant gas field under the geologic conditions of sufficient gas source and good reservoir. It is predicted that other giant gas fields the same as or even larger than Puguang could be found in the areas where both reef -flat reservoirs in Feixianguan formation and gypsum and salt cap rocks in Jialingjiang formation are developed, such as Wanzhou and Da- zhu areas, in South China.%分析了北美潘汉得—胡果顿气田和我国普光气田的地质背景、成藏条件与成藏过程指出,二者均发育多套烃源岩,储集层物性均较好,盖层岩类均为膏盐岩,经后期多期变动与调整而定型于晚期。但二者间最显著的差异在于盖层的发育程度:前者的膏盐岩直接盖层分布范围广、厚度巨大、断层不发育,明显优于普光气田。说明在气源充足、储集层发育良好的地质条件下,盖层及保存条件是形成大气田的最关键因素。据此预测,在中国南方飞仙关组礁滩优质储集层和嘉陵江组膏盐岩盖层发育重叠区,如万州和大竹地区,有望发现更大规模的天然气田。

  9. Petroleum in the Junggar basin, northwestern China

    Science.gov (United States)

    Taner, Irfan; Kamen-Kaye, Maurice; Meyerhoff, Arthur A.

    The Junggar basin occupies a large triangular area of some 130 000 km 2 in northwestern China. Situated between the Altay Shan (Altay Range) on the northeast and the Tian Shan (Tian Range) on the southwest, and between lesser ranges around the remainder of its periphery, the Junggar basin is completely intermontane. Its history as a basin began in the Permian, and continued as various uplifts and downwarps evolved. Through the Paleozoic the characteristics of the Junggar basin area were largely geosynclinal and marine. Its post-Permian development took place exclusively in continental regimes. Inhabitants of the Junggar basin have known and utilized its numerous oil and asphalt seeps and its spectacular spreads of asphalt for more than 2000 years, especially in the Karamay-Urho thrust belt near the northwestern rim. The first discovery of oil in the modern sense came at Dushanzi, one of the steeply folded anticlines of theÜrümqi foredeep near the southern rim. The first shallow oil in the Karamay-Urho thrust belt came in 1937, followed by commercial production in the Karamay field in 1955. Output continued to be modest until wells were drilled through local thrusts and reverse faults in the early 1980s. By 1985, cumulative production of the Karamay group of fields had reached 42,000,000 t (metric tonnes) (306,000,000 bbl), with a calculated minimum ultimate recovery of 280,000,000 t (2 billion bbl). Principal production comes from Permian and Triassic strata in continental facies. Apart from marine Mid and Upper Carboniferous strata, source rocks occur mainly in fine-grained lacustrine detrital beds of the Permian, the Triassic, the Jurassic and the Tertiary. Several uplifts and downwarps elsewhere in the Junggar basin remain to be drilled comprehensively. Results from such drilling may enhance the very important position that the Junggar already has attained in the hierarchy of China's onshore basins.

  10. BASIN PEAT SORBTION CAPACITY IMPROVEMENT FOR OIL SPILL RESPONSE

    Directory of Open Access Journals (Sweden)

    CHUKHAREVA N.V.

    2012-01-01

    Full Text Available This article is concerned with the investigation of basin peat sorption capacity in Tomsk field. Experimental results showed the thermal treatment efficiency of sorbent production for oil spill response.

  11. Erosion and deposition by supercritical density flows during channel avulsion and backfilling: Field examples from coarse-grained deepwater channel-levée complexes (Sandino Forearc Basin, southern Central America)

    Science.gov (United States)

    Lang, Jörg; Brandes, Christian; Winsemann, Jutta

    2017-03-01

    Erosion and deposition by supercritical density flows can strongly impact the facies distribution and architecture of submarine fans. Field examples from coarse-grained channel-levée complexes from the Sandino Forearc Basin (southern Central America) show that cyclic-step and antidune deposits represent common sedimentary facies of these depositional systems and relate to the different stages of avulsion, bypass, levée construction and channel backfilling. During channel avulsion, large-scale scour-fill complexes (18 to 29 m deep, 18 to 25 m wide, 60 to > 120 m long) were incised by supercritical density flows. The multi-storey infill of the large-scale scour-fill complexes comprises amalgamated massive, normally coarse-tail graded or widely spaced subhorizontally stratified conglomerates and pebbly sandstones, interpreted as deposits of the hydraulic-jump zone of cyclic steps. The large-scale scour-fill complexes can be distinguished from small-scale channel fills based on the preservation of a steep upper margin and a coarse-grained infill comprising mainly amalgamated hydraulic-jump zone deposits. Channel fills include repeated successions deposited by cyclic steps with superimposed antidunes. The deposits of the hydraulic-jump zone of cyclic steps comprise regularly spaced scours (0.2 to 2.6 m deep, 0.8 to 23 m long) infilled by intraclast-rich conglomerates or pebbly sandstones, displaying normal coarse-tail grading or backsets. These deposits are laterally and vertically associated with subhorizontally stratified, low-angle cross-stratified or sinusoidally stratified sandstones and pebbly sandstones, which were deposited by antidunes on the stoss side of the cyclic steps during flow re-acceleration. The field examples indicate that so-called spaced stratified deposits may commonly represent antidune deposits with varying stratification styles controlled by the aggradation rate, grain-size distribution and amalgamation. The deposits of small-scale cyclic

  12. The forming factors and distribution rules of giant oil and gas fields in the coastal basins of West Africa%西非海岸盆地带大油气田形成条件与分布规律探析

    Institute of Scientific and Technical Information of China (English)

    郑应钊; 何等发; 马彩琴; 万德辉

    2011-01-01

    目的 探究西非海岸盆地带大油气田形成条件和分布的规律,为发现更多的大油气田提供理论依据.方法 从西非海岸盆地带沉积盆地分布和已发现的大油气田分布情况入手,分析其形成的有利条件,总结出西非最主要的两大含油气盆地——尼日尔三角洲盆地和下刚果盆地的含油气系统的相似性和差异性,归纳出西非大油气田形成及分布的规律.结果 在西非海岸盆地带,盐岩层的发育对各盆地油气的成藏和分布有重大影响.盐岩发育的大西洋带中段,盆地油气富集程度明显高于盐岩不发育的南段、北段盆地.西非海岸盆地带的含油气系统可分为盐下、盐上两套大的含油气系统,盐下含油气系统的烃源岩是湖相页岩,储层为河流相、三角洲相、滨海相砂岩,阿普第期蒸发岩层为盖层;盐上含油气系统的烃源岩是海相页岩,储层主要为浊积岩,盖层为泥页岩.结论 在西非海岸盆地带,大油气田多分布于近海或沿岸,受构造位置和沉积相带控制,形成多个油气富集带,具有垂直三角洲的沉积走向,呈带状富集的规律.由油气产出的岩性来看,其主要产出于碎屑岩储层,碳酸岩储层次之.产油层系以第三系为主,其次为白垩系.在南段盆地,形成了大气田;在中段的下刚果盆地和加蓬海岸盆地,只形成了大油田;在尼日尔三角洲盆地,形成了大油田、大气田共存的局面;西非北段盆地尚未发现大油气田.未来在西非海岸带中段盆地的深水浊积岩区有望发现更多的大油气田.%Aim To study the forming factors of giant oil and gas fields in the coastal basins of West Africa, and summarize the fields' distribution rules in order to help the hydrocarbon exploration in the future. Methods Based on the distribution of sedimentary basins and giant oil and gas fields in West Africa Coast, the factors of its forming is analyzed, the similarity

  13. Exploration Experience and Problem concerning Deep Basin Gas in the Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    MaXinhua

    2004-01-01

    Deep basin gas (DBG) reservoirs, in view of the characteristics of their main parts containing gas, are a type of subtle stratigraphic lithologic traps. But they have different reservoir-forming principles, especially in the distribution of oil, gas and water. DBG is characterized by gas-water invertion, namely the water located above the gas; however, normal non-anticline subtle reservoirs have normal distribution of gas and water, namely the water located under the gas. The theory of DBG broke the conventional exploration idea that gas is usually found in the high part of reservoir and water is under the gas. So, it provided a wide field and a new idea for the exploration of natural gas. Recently Ben E. Law (2002), in his article entitled "Basin-centered Gas Systems", discussed global DBG systemically. He listed 72 basins or areas containing known or suspected DBG, covering North America, South America, Europe, Asia-Pacific, South Asia, Middle East and Africa. Ordos basin, the Sichuan basin and the Jungar basin in China are presented and assumed to be of very high possibility. In China more attention has been paid to the research and exploration of DBG in the past years. The symposiums on DBG were held twice, in Guangzhou in 1998 and in Xi'an in 2000 respectively. In 2002 in particular, the publication of the book named Deep Basin Gas in China by Professor Wangtao indicated that China has entered a new stage in the research on DBG. Meanwhile, it is more cheering that the exploration of DBG in the Ordos Basin has achieved remarkable success. Therefore, analyzing the exploration experiences and problems regarding the Ordos basin will promote the exploration and research of DBG in China.

  14. Reserves in western basins

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, R.H.; Cotton, B.W. [Scotia Group, Dallas, TX (United States)

    1995-04-01

    The objective of this project is to investigate the reserves potential of tight gas reservoirs in three Rocky Mountain basins: the Greater Green River (GGRB), Uinta and Piceance basins. The basins contain vast gas resources that have been estimated in the thousands of Tcf hosted in low permeability clastic reservoirs. This study documents the productive characteristics of these tight reservoirs, requantifies gas in place resources, and characterizes the reserves potential of each basin. The purpose of this work is to promote understanding of the resource and to encourage its exploitation by private industry. At this point in time, the GGRB work has been completed and a final report published. Work is well underway in the Uinta and Piceance basins which are being handled concurrently, with reports on these basins being scheduled for the middle of this year. Since the GGRB portion of the project has been completed, this presentation win focus upon that basin. A key conclusion of this study was the subdivision of the resource, based upon economic and technological considerations, into groupings that have distinct properties with regard to potential for future producibility, economics and risk profile.

  15. Basin deconstruction-construction: Seeking thermal-tectonic consistency through the integration of geochemical thermal indicators and seismic fault mechanical stratigraphy ​- Example from Faras Field, North Western Desert, Egypt

    Science.gov (United States)

    Pigott, John D.; Abouelresh, Mohamed O.

    2016-02-01

    To construct a model of a sedimentary basin's thermal tectonic history is first to deconstruct it: taking apart its geological elements, searching for its initial conditions, and then to reassemble the elements in the temporal order that the basin is assumed to have evolved. Two inherent difficulties implicit to the analysis are that most organic thermal indicators are cumulative, irreversible and a function of both temperature and time and the non-uniqueness of crustal strain histories which complicates tectonic interpretations. If the initial conditions (e.g. starting maturity of the reactants and initial crustal temperature) can be specified and the boundary conditions incrementally designated from changes in the lithospheric heat engine owing to stratigraphic structural constraints, then the number of pathways for the temporal evolution of a basin is greatly reduced. For this investigation, model input uncertainties are reduced through seeking a solution that iteratively integrates the geologically constrained tectonic subsidence, geochemically constrained thermal indicators, and geophysically constrained fault mechanical stratigraphy. The Faras oilfield in the Abu Gharadig Basin, North Western Desert, Egypt, provides an investigative example of such a basin's deconstructive procedure. Multiple episodes of crustal extension and shortening are apparent in the tectonic subsidence analyses which are constrained from the fault mechanical stratigraphy interpreted from reflection seismic profiles. The model was iterated with different thermal boundary conditions until outputs best fit the geochemical observations. In so doing, the thermal iterations demonstrate that general relationship that basin heat flow increases decrease vertical model maturity gradients, increases in surface temperatures shift vertical maturity gradients linearly to higher values, increases in sediment conductivities lower vertical maturities with depth, and the addition of "ghost" layers

  16. Structural characteristics and petroliferous features of Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Using the modern tectonic geology theories and methods such as the plate tectonic analysis, the paleo-struc- ture analysis, the structural-lithofacies analysis, and the fault related fold and petroleum system, and combining with the seismic data, well drilling data and the circumferential field geology, study on the structural characteristics and petroleum prospect in the Tarim Basin has been carried out. Results show that the Tarim Basin is a large superimposition and combination basin with continental crustal basement, composed of a Paleozoic craton and Meso-Cenozoic foreland basins. The characteristics of the basin are: the kernel part of the basin is the marine facies Paleozoic craton, superimposed 4 continental facies foreland basins. Though the scale of the paleozoic craton of the Tarim Basin is relatively small, the structure is steady. The petroleum prospect of the Paleozoic craton is: multiphase pool-generation and accumulation controlled by ancient uplift. The Meso-Cenozoic foreland basins in the Tarim Basin, which are distributed on the cratonic circumference and are a long-term subsidence, turned into rejuvenated foreland basins after the Meso-Cenozoic period. The petroleum prospects are: coal-bed generating hydrocarbon, abundant natural gas, pool-generation in later and recent periods, the oil and gas distribution controlled by the foreland thrust belt. The structural characteristics of Tarim provide it with a superimposition and combination petroleum system of multiple resources, multiple reservoirs and multiphase pool-generation. The oil and gas exploration prospect covers two large fields: the Paleozoic craton and the Meso-Cenozoic foreland thrust belt.

  17. Oil and gas resources in the West Siberian Basin, Russia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    The primary objective of this study is to assess the oil and gas potential of the West Siberian Basin of Russia. The study does not analyze the costs or technology necessary to achieve the estimates of the ultimate recoverable oil and gas. This study uses reservoir data to estimate recoverable oil and gas quantities which were aggregated to the field level. Field totals were summed to a basin total for discovered fields. An estimate of undiscovered oil and gas, from work of the US Geological Survey (USGS), was added to give a total basin resource volume. Recent production decline points out Russia`s need to continue development of its discovered recoverable oil and gas. Continued exploration is required to discover additional oil and gas that remains undiscovered in the basin.

  18. Mitigation : Closed Basin Project

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The upcoming meeting on waterfowl mitigation for the Closed Basin Project will have several people talk about possible changes to the waterfowl mitigation program. A...

  19. Tulare Basin protection plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Tulare Basin Protection Plan has been initiated by The Nature Conservancy to elucidate the problems and opportunities of natural diversity protection....

  20. BASINS Framework and Features

    Science.gov (United States)

    BASINS enables users to efficiently access nationwide environmental databases and local user-specified datasets, apply assessment and planning tools, and run a variety of proven nonpoint loading and water quality models within a single GIS format.

  1. California Air Basins

    Data.gov (United States)

    California Department of Resources — Air ResourcesCalifornia Air Resources BoardThe following datasets are from the California Air Resources Board: * arb_california_airbasins - California Air BasinsThe...

  2. Watershed Planning Basins

    Data.gov (United States)

    Vermont Center for Geographic Information — The Watershed Planning Basin layer is part of a larger dataset contains administrative boundaries for Vermont's Agency of Natural Resources. The dataset includes...

  3. Minisparker seismic-reflection data of field activity S-5-09-SC: San Pedro Basin, offshore southern California from 2009-07-06 to 2009-07-10

    Science.gov (United States)

    Sliter, Ray W.; Conrad, James E.; Ryan, Holly F; Triezenberg, Peter

    2017-01-01

    This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2009 to explore a possible connection between the San Diego Trough Fault and the San Pedro Basin Fault. The survey is in the San Pedro Basin between Santa Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic penetration spanned tens to several hundreds of meters, variable by location.

  4. Chirp seismic-reflection data of field activity S-5-09-SC: San Pedro Basin, offshore southern California from 2009-07-06 to 2009-07-10

    Science.gov (United States)

    Sliter, Ray W.; Conrad, James E.; Ryan, Holly F.; Triezenberg, Peter

    2017-01-01

    This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2009 to explore a possible connection between the San Diego Trough Fault and the San Pedro Basin Fault. The survey is in the San Pedro Basin between Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an Edgetech 512 Chirp subbottom profiling system. Subbottom acoustic penetration spanned tens to hundreds of meters, variable by location.

  5. Aerial field guide

    Science.gov (United States)

    Nummedal, D.

    1978-01-01

    There are two overflights planned for the field conference; one for the Cheney-Palouse tract of the eastern channeled scabland, the other covering the coulees and basins of the western region. The approximate flight lines are indicated on the accompanying LANDSAT images. The first flight will follow the eastern margin of this large scabland tract, passing a series of loess remnants, gravel bars and excavated rock basins. The western scablands overflight will provide a review of the structurally controlled complex pattern of large-scale erosion and deposition characteristic of the region between the upper Grand Coulee (Banks Lake) and the Pasco Basin.

  6. K Basin Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    PECH, S.H.

    2000-08-23

    This report describes the methodology used in conducting the K Basins Hazard Analysis, which provides the foundation for the K Basins Final Safety Analysis Report. This hazard analysis was performed in accordance with guidance provided by DOE-STD-3009-94, Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports and implements the requirements of DOE Order 5480.23, Nuclear Safety Analysis Report.

  7. K Basins Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    WEBB, R.H.

    1999-12-29

    This report describes the methodology used in conducting the K Basins Hazard Analysis, which provides the foundation for the K Basins Safety Analysis Report (HNF-SD-WM-SAR-062, Rev.4). This hazard analysis was performed in accordance with guidance provided by DOE-STD-3009-94, Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports and implements the requirements of DOE Order 5480.23, Nuclear Safety Analysis Report.

  8. Transport of Pb and Zn by carboxylate complexes in basinal ore fluids and related petroleum-field brines at 100°C: the influence of pH and oxygen fugacity

    Directory of Open Access Journals (Sweden)

    Giordano Thomas H

    2002-09-01

    Full Text Available It is well established through field observations, experiments, and chemical models that oxidation (redox state and pH exert a strong influence on the speciation of dissolved components and the solubility of minerals in hydrothermal fluids. log –pH diagrams were used to depict the influence of oxygen fugacity and pH on monocarboxylate- and dicarboxylate-transport of Pb and Zn in low-temperature (100°C hydrothermal ore fluids that are related to diagenetic processes in deep sedimentary basins, and allow a first-order comparison of Pb and Zn transport among proposed model fluids for Mississippi Valley-type (MVT and red-bed related base metal (RBRBM deposits in terms of their approximate pH and conditions. To construct these diagrams, total Pb and Zn concentrations and Pb and Zn speciation were calculated as a function of log and pH for a composite ore-brine with concentrations of major elements, total sulfur, and total carbonate that approximate the composition of MVT and RBRBM model ore fluids and modern basinal brines. In addition to acetate and malonate complexation, complexes involving the ligands Cl-, HS-, H2S, and OH- were included in the model of calculated total metal concentration and metal speciation. Also, in the model, Zn and Pb are competing with the common-rock forming metals Ca, Mg, Na, Fe, and Al for the same ligands. Calculated total Pb concentration and calculated total Zn concentration are constrained by galena and sphalerite solubility, respectively. Isopleths, in log –pH space, of the concentration of Pb and concentration of Zn in carboxylate (acetate + malonate complexes illustrate that the oxidized model fluids of T. H. Giordano (in Organic Acids in Geological Processes, ed. E. D. Pittman and M. D. Lewan, Springer-Verlag, New York, 1994, pp. 319–354 and G. M. Anderson (Econ. Geol., 1975, 70, 937–942 are capable of transporting sufficient amounts of Pb (up to 10 ppm and Zn (up to 100 ppm in the form of carboxylate

  9. Production strategy and technological challenges arisen with the low permeability gas reservoirs in the Mexilhao, Urugua and Tambau Fields, Campos Basin, Southeast, Brazil; Estrategia de producao e desafios tecnologicos no desenvolvimento da producao de gas nos reservatorios de baixa permeabilidade dos Campos de Mexilhao, Urugua e Tambau, Bacia de Santos

    Energy Technology Data Exchange (ETDEWEB)

    Barroso, Alberto da Silva; Silva, Celso Tarcisio de Souza; Pires, Luis Carlos Gomes; Damasceno, Luis Carlos; Filoco, Paulo Roberto [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Mexilhao, Urugua and Tambau Fields are located in the North part of the Santos Basin will produce together 18 106 m3/d of gas and 45 000 bbl/d of oil and condensate. Besides the contribution to attend the country gas demand the production of these fields starts the establishment of a minimum gas production, transportation and processing infra-structure, that are flexible enough to permit increasing in production from possible upsides. This new production pole has a strategic importance because it will increment gas production close to the main brazilian consumer center. Mexilhao, Urugua and Tambau Fields are located in the North part of the Santos Basin will produce together 18 106 m3/d of gas and 45 000 bbl/d of oil and condensate. Besides the contribution to attend the country gas demand the production of these fields starts the establishment of a minimum gas production, transportation and processing infra-structure, that are flexible enough to permit increasing in production from possible upsides. This new production pole has a strategic importance because it will increment gas production close to the main brazilian consumer center.(author)

  10. Turbulent Flow Measurement in Vortex Settling Basin

    Directory of Open Access Journals (Sweden)

    Jafar Chapokpour

    2011-12-01

    Full Text Available This paper presents the findings of an experimental study on the three-dimensional turbulent flow field in vortex settling basin. An ADV (Acoustic Doppler Velocity Meter were used to catch 3D velocitycomponents inside the basin. Detailed measurements of time-averaged velocity components, turbulent intensity components and turbulent kinetic energy were determined at different radial sections of chamber. Also the normalized time averaged absolute velocity of 3D components in contour type exhibition were conducted and it was found that the absolute velocity generally is influenced by u component of flow. It trends from high magnitude in basin center to the constant magnitude in basin side wall. The normalized turbulent intensity ofthree components was investigated individually. It was found that intensity of 3D components in vicinity of central air core is higher than other regions, decreasing by moving towards basin sidewall except for the sections that influenced directly by entrance flow jet and sidewall exiting overflow. The results of turbulence kinetic energy also had the same interpretation like turbulence intensity and affected by the same boundary conditions which cover turbulence intensity of 3 velocity components overly.

  11. Geometry of the inverted Cretaceous Chañarcillo Basin based on 2-D gravity and field data. An approach to the structure of the western Central Andes of northern Chile

    Directory of Open Access Journals (Sweden)

    F. Martínez

    2015-08-01

    Full Text Available This paper discusses an integrated approach that provides new ideas about the structural geometry of the NNE-striking, Cretaceous Chañarcillo Basin located along the eastern Coastal Cordillera in the western Central Andes of northern Chile (27–28° S. The results obtained from the integration of two transverse (E–W gravity profiles with previous geological information, show that the architecture of this basin is defined by a large NNE–SSE-trending and east-vergent anticline ("Tierra Amarilla Anticlinorium", which is related to the positive reactivation of a former Cretaceous normal fault (Elisa de Bordos Master Fault. Moreover, intercalations of high and low gravity anomalies and steep gravity gradients reveal a set of buried, west-tilted half-grabens associated with a synthetic normal fault pattern. These results, together with the uplift and folding style of the Cretaceous syn-rift recognized within the basin, suggest that their complete structural geometry could be explained by an inverted fault system linked to the shortening of pre-existing Cretaceous normal fault systems. Ages of the synorogenic deposits exposed unconformably over the frontal limb of the Tierra Amarilla Anticlinorium confirm a Late Cretaceous age for the Andean deformation and tectonic inversion of the basin.

  12. Tectonic Characteristics and Evolution of Bohai Bay Basin, China

    Institute of Scientific and Technical Information of China (English)

    LIU Pengju; ZHANG Meisheng; SUN Xiaomeng; YANG Baojun

    2002-01-01

    Synthetical analyzing the deep geophysical data within Bohai bay basin the authors detect the deep crustal structure presenting high geothermal flux, thinned crust and arched Moho discontinuity, and the basin basement belongs to rigid continental crust. The development of the basin was controlled by two - dimensional faults in NNE and NWW directions. The tectonic units of the basin can be subdivided into three structural divisions: the east, middle and west division. The basin is considered as a continental rift. The tectonic background and regional right - lateral stress field during the late Cretaceous and Paleogene were a compound result of the Kula Plate W - directional subducting under Eurasia Continental Plate in 80 ~ 74Ma and the Philippine sea Plate W -directional subducting under the Eurasia Continental Plate since 60Ma, the long-rang effect of the India Continental Plate wedging into the Eurasia Continental Plate and of the Siberia Plate SE - directional relatively moving.

  13. Polyphase basin evolution of the Vienna Basin inferred from 3D visualization of sedimentation setting and quantitative subsidence

    Science.gov (United States)

    Lee, Eun Young; Novotny, Johannes; Wagreich, Michael

    2016-04-01

    This study analyzed and visualized data from 210 wells using a MATLAB-based program (BasinVis 1.0) for 3D visualization of sediment distribution, thickness, and quantitative subsidence of the northern and central Vienna Basin. The sedimentation settings for selected horizons were visualized to 3D sediment distribution maps, isopach maps, and cross-sections. Subsidence of the study area resulted in 3D subsidence depth and rate maps of basement and tectonic subsidences. Due to the special position of the Vienna Basin, the basin evolution was influenced by the regional tectonics of surrounding units. The 2D/3D maps provided insights into the polyphase evolution of the Vienna Basin, which is closely related to changes in the changing regional stress field and the paleoenvironmental setting. In the Early Miocene, the sedimentation and subsidence were shallow and E-W/NE-SW trending, indicating the development of piggy-back basins. During the late Early Miocene, maps show wider sedimentation and abruptly increasing subsidence by sinistral strike-slip faults, which initiated the Vienna pull-apart basin system. The sediments of the Early Miocene were supplied through a small deltaic system entering from the south. After thin sedimentation and shallow subsidence of the early Middle Miocene, the development of the Vienna Basin was controlled and accelerated mainly by NE-SW trending synsedimentary normal faults, especially the Steinberg fault. From the Middle Miocene, the subsidence was decreasing overall, however the tectonic subsidence show regionally different patterns. This study suggests that a major tensional regime change, from transtension to E-W extension, caused laterally varying subsidence across the Vienna Basin. The Late Miocene was characterized by the slowing down of basement and tectonic subsidence. From the middle Middle to Late Miocene, enormous amount of sediments supplied by a broad paleo-Danube delta complex on the western flank of the basin. The latest

  14. Relationships between basin architecture, basin closure, and occurrence of sulphide-bearing schists

    DEFF Research Database (Denmark)

    Kalliomäki, Henrik; Torvela, Taija; Moreau, Julien

    2014-01-01

    We present field observations from the Palaeoproterozoic volcano-sedimentary Tampere palaeobasin, where the primary structures have been exceptionally well preserved. We use the observations to construct a new tectonic model for the southeastern margin of the Tampere basin during its inversion an...

  15. Tectonics and Petroleum Potential of the East China Sea Shelf Rift Basin

    Institute of Scientific and Technical Information of Chin