Sample records for yanchang formation ordos

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

    Xie, Xiangyang


    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.

  2. Characteristics of hydrothermal sedimentation process in the Yanchang Formation, south Ordos Basin, China: Evidence from element geochemistry

    He, Cong; Ji, Liming; Wu, Yuandong; Su, Ao; Zhang, Mingzhen


    Hydrothermal sedimentation occurred in the Triassic Yanchang Formation, Ordos Basin, China. However, their macroscopic features at the scale of the stratum and hydrothermal sources still lack correlational research. This paper performed element geochemical study on a large number of core samples collected from the Yanchang Formation of a new drilling well located in the south Ordos Basin. The SiO2/(K2O + Na2O) vs. MnO/TiO2 crossplot and Fe vs. Mn vs. (Cu + Co + Ni) × 10 ternary diagram demonstrate that the Yanchang stratum in the study area has, in general, hydrothermal components. The Al/(Al + Fe + Mn) and (Fe + Mn)/Ti ratios of the core samples range from 0.34 to 0.84 and 4.81 to 50.54, averaging 0.66 and 10.67, respectively, indicating that the stratum is a set of atypical hydrothermal sedimentation with much terrigenous input. Data analysis shows that the hydrothermal source in the study area was from the deep North Qinling Orogen around the south margin of the basin, where some active tectonic and volcanic activities took place, rather than from the relatively stable internal basin. Early Indosinian movement and volcanic activities activated basement faults around the southern margin of the basin, providing vents for the deep hydrothermal fluid upwelling. The hydrothermal indicators suggest that the study area experienced 4 episodes of relatively stronger hydrothermal activity, namely during the Chang 10, Chang 9-1, Chang 7-3 and Chang 6-2 periods. We also propose a new hydrothermal sedimentation model of hydrothermal fluids overflowing from basin margin faults, for the Yanchang Formation, which is reported here for the first time.

  3. Geochemical Characteristics and Origins of the Crude Oil of Triassic Yanchang Formation in Southwestern Yishan Slope, Ordos Basin

    Xiaoli Zhang


    Full Text Available Biomarker compounds that derived from early living organisms play an important role in oil and gas geochemistry and exploration since they can record the diagenetic evolution of the parent materials of crude oil and reflect the organic geochemical characteristics of crude oil and source rocks. To offer scientific basis for oil exploration and exploitation for study area, gas chromatography-mass spectrometry method is applied to study the biomarker compounds of crude oil in Southwestern Yishan Slope of Ordos Basin, through qualitatively and quantitatively analyzing separated materials. The crude oil of Yanchang Formation and the source rocks of Yan’an and Yanchang Formation were collected in order to systematically analyze the characteristics of the biomarker compounds in saturated hydrocarbon fractions and clarify the organic geochemical characteristics of crude oil. The distribution and composition of various types of hydrocarbon biomarker compounds in crude oil suggest that the parent materials of crude oil are composed of hydrobiont and terrigenous plants, and the crude oil is mature oil which is formed in the weak reducing fresh water environment. Oil source correlation results show that the crude oil of Yanchang Formation in Yishan Slope is sourced from the source rocks of Chang 7 subformation.

  4. The oleaginous Botryococcus from the Triassic Yanchang Formation in Ordos Basin, Northwestern China: Morphology and its paleoenvironmental significance

    Ji, Li-ming; Yan, Kui; Meng, Fan-wei; Zhao, Min


    High abundance but rather low diversity algal fossils were found in the hydrocarbon source rocks of the Ch 7-2-Ch 7-3 section, Triassic Yanchang Formation in the Xifeng area of southwest Ordos Basin, which are mainly composed of prolific Leiosphaeridia and Botryococcus. Botryococcus colonies are of various forms; the majority is nubbly, with some of cluster and cotton shape. The nubbly colonies appear globular, cordiform, ternate petal, obtuse triangle, chrysanthemum shape and so on. Most Botryococcus are saffron or brown and are frequently covered with clay under transmission microscope, and shows strong yellow and light brown under fluorescence microscope. Botryococcus could live in freshwater and brackish water. The Botryococcus colonies that lived in fresh water are small with small single cells arranged radially, with undulant or indented edges. The Botryococcus colonies that lived in brackish water are bigger, with larger single cells arranged irregularly, with slippery contours. The most of Botryococcus are discovered from the organic-rich argillaceous sediment with abundant pyrites in the semi- and deep-lake facies, and shows they were preserved in low-energy reducing environments. Taphonomic characteristics of various microfossils and the present of Pediastrum in the phytoplankton flora indicate that they are in situ or near burial. The lake area of the Ordos Basin was gradually expanding and reaching its most extensive flood surface in the Ch 7 of Yanchang Formation interval during the Middle and Late Triassic, with warm climate, plentiful rainfall, and luxuriant vegetation, as determined by the environmental analysis with Botryococcus in Xifeng area. The presence of two ecological types of Botryococcus indicates that the salinity of lake water was fluctuating in the Ch 7 interval. The occurrence of symbiotic acritarchs and geochemical salinity indices show that the Ordos Lake was a typical fresh-water lake, which was gradually desalted, and its salinity

  5. Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

    Ziliang Liu

    Full Text Available A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km. The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front

  6. A deltaic-sediment gravity flow depositional system in the Upper Triassic Yanchang Formation, Southwest Ordos Basin, China

    Gao, Yi; Jiang, Zaixing; Liu, Shengqian


    The Ordos Basin, located in central China, is a large-scale residual Mesozoic intracratonic down-warped basin. It is the second largest and the most productive oil-gas-bearing basin in China. The Upper Triassic Yanchang Formation is characterized by fluvial-lacustrine facies. It can be subdivided into 10 stratigraphic sublayers (Ch1-Ch10 from top to bottom), and the Ch81 interval is an important oil-gas reservoir in this basin. For a long time, sandstones in this interval are interpreted to be deposited in a shallow water braided delta sedimentary system in the southwest of the basin. During deposition of this interval, the water is quite shallow, and there are no sediment gravity flow deposits. In this research, based mainly on core observation and description, as well as well logging and seismic data, we proposed that sediment gravity flow deposits are well-developed in the study area in the southwestern Ordos Basin. Four lithofacies assemblages have been recognized: (i) thick-bedded sandstone with abundant lamination structures as channelized sandy deposits in braided delta; (ii) thick-bedded chaotically contorted sandstone as sandy slump; (iii) thick-bedded structureless sandstone with floating mudstone clasts as sandy debrite, or with spaced planar lamination as high-density turbidite; (iv) thin-bedded ripple cross-laminated sandstone as low-density turbidite. On the basis of core evidence of a sedimentary cross-section along flow direction with six cored wells, the most possible trigger of sediment gravity flow is delta-front collapsing. Through downslope transportation, one type of gravity flow can transform to another type. Deltaic channelized sandstones are dominant in the proximal area. Sandy slumps are dominant in the middle area, which is formed by collapsing of deltaic deposits and transform to high density turbidite and sandy debrite in the distal area. Few low-density turbidite is shown. With additional geochemical evidence, it can be confidently

  7. Numerical modeling of secondary migration and its applications to Chang-6 Member of Yanchang Formation (Upper Triassic), Longdong area, Ordos Basin, China

    LUO; XiaoRong; YU; Jian; ZHANG; LiuPing; YANG; Yang; CHEN; RuiYin; CHEN; ZhanKun; ZHOU; Bo


    Mathematic modeling, established on the basis of physical experiments, is becoming an increasingly important tool in oil and gas migration studies. This technique is based on the observation that hydrocarbon migration tends to take relative narrow pathways. A mathematical model of hydrocarbon migration and accumulation is constructed using the percolation theory. It is then calibrated using physical experimental results, and is tested under a variety of conditions, to understand the applicability of the model in different migration cases. Through modeling, dynamic conditions of large-scale migration pathways within homogeneous formations can be evaluated. Basin-scale hydrocarbon migration pathways and their characteristics are analyzed during the model application to the Chang-8 Member of the Triassic Yanchang Formation in Longdong area of Ordos Basin. In heterogeneous formations, spatial changes in fluid potential determine the direction of secondary migration, and heterogeneity controls the characteristics and geometry of secondary migration pathways.

  8. Sedimentary facies and depositional model of shallow water delta dominated by fluvial for Chang 8 oil-bearing group of Yanchang Formation in southwestern Ordos Basin, China

    陈林; 陆永潮; 吴吉元; 邢凤存; 刘璐; 马义权; 饶丹; 彭丽


    A systematic analysis of southwestern Ordos Basin’s sedimentary characteristics, internal architectural element association styles and depositional model was illustrated through core statistics, well logging data and outcrop observations in Chang 8 oil-bearing group. This analysis indicates that shallow water delta sediments dominated by a fluvial system is the primary sedimentary system of the Chang 8 oil-bearing group of the Yanchang Formation in southwestern Ordos Basin. Four microfacies with fine grain sizes are identified: distributary channels, sheet sandstone, mouth bar and interdistributary fines. According to the sandbody’s spatial distribution and internal architecture, two types of sandbody architectural element associations are identified: amalgamated distributary channels and thin-layer lobate sandstone. In this sedimentary system, net-like distributary channels at the delta with a narrow ribbon shape compose the skeleton of the sandbody that extends further into the delta front and shades into contiguous lobate distribution sheet sandstone in the distal delta front. The mouth bar is largely absent in this system. By analyzing the palaeogeomorphology, the palaeostructure background, sedimentary characteristics, sedimentary facies types and spatial distribution of sedimentary facies during the Chang 8 period, a distinctive depositional model of the Chang 8 shallow water fluvial-dominated delta was established, which primarily consists of straight multi-phase amalgamated distributary channels in the delta plain, net-like distributary channels frequently diverting and converging in the proximal delta front, sheet sandstones with dispersing contiguous lobate shapes in the distal delta front, and prodelta or shallow lake mudstones.

  9. Distribution and geological significance of 17α(H)-diahopanes from different hydrocarbon source rocks of Yanchang Formation in Ordos Basin

    ZHANG WenZheng; YANG Hua; HOU LiHui; LIU Fei


    Based on GC-MS testing data of many saturated hydrocarbon samples, 17α(H)-30 diahopanes (C30*) are extensively distributed in the lacustrine hydrocarbon source rocks of the Yanchang Formation in Ordos Basin, but show remarkable differences in relative abundance among various source rocks. Generally, Chang 7 high-quality source rock (oil shale) developed in deep lake anoxic environment shows lower C30* content, whereas Chang 6-9 dark mudstone developed in shallow to semi-deep lake, sub-oxidiz- ing environment shows relatively high to high C30* value. Particularly, Chang 7 and Chang 9 black mudstones in Zhidan region in the northeast of the lake basin show extremely high C30* value. A com- parative analysis was made based on lithology, organic types and various geochemical parameters indicative of redox environment, and the results indicate that environmental factors such as redox set- tings and lithology are key factors that control the C30* relative abundance, while organic types and maturity may be minor factors. High to extremely high C30* values are indicative of sub-oxidizing envi- ronment of fresh-brackish water and shallow to semi-deep lake. Therefore, research on C30* relative content and distribution in lacustrine hydrocarbon source rocks in the Yanchang Formation, especially on the difference in C30* between Chang 7 high-quality source rocks (oil shale) and Chang 6-91 source rocks (dark mudstone), will provide an important approach for classification of Mesozoic lacustrine crudes and detailed oil-source correlation in the basin.

  10. Distribution and geological significance of 17α(H)-diahopanes from different hydrocarbon source rocks of Yanchang Formation in Ordos Basin


    Based on GC-MS testing data of many saturated hydrocarbon samples, 17α(H)-C30 diahopanes (C30*) are extensively distributed in the lacustrine hydrocarbon source rocks of the Yanchang Formation in Ordos Basin, but show remarkable differences in relative abundance among various source rocks. Generally, Chang 7 high-quality source rock (oil shale) developed in deep lake anoxic environment shows lower C30* content, whereas Chang 6-9 dark mudstone developed in shallow to semi-deep lake, sub-oxidizing environment shows relatively high to high C30* value. Particularly, Chang 7 and Chang 9 black mudstones in Zhidan region in the northeast of the lake basin show extremely high C30* value. A comparative analysis was made based on lithology, organic types and various geochemical parameters indicative of redox environment, and the results indicate that environmental factors such as redox settings and lithology are key factors that control the C30* relative abundance, while organic types and maturity may be minor factors. High to extremely high C30* values are indicative of sub-oxidizing environment of fresh-brackish water and shallow to semi-deep lake. Therefore, research on C30* relative content and distribution in lacustrine hydrocarbon source rocks in the Yanchang Formation, especially on the difference in C30* between Chang 7 high-quality source rocks (oil shale) and Chang 6-91 source rocks (dark mudstone), will provide an important approach for classification of Mesozoic lacustrine crudes and detailed oil-source correlation in the basin.

  11. The deep-lake deposit in the Upper Triassic Yanchang Formation in Ordos Basin, China and its significance for oil-gas accumulation


    The deep-lake facies of the Yanchang Formation represents a large outflowing lake basin in the Ordos area. Its deposition can be divided into four stages: lake genetic and expanding stage, peak stage, inversion stage and dying stage. All the stages are obviously consistent with the evolution of depositional environment and the paleoclimate in the region. The study indicates that the lake basin has evolution fluctuations from highstand to lowstand for four times in its evolution history, and the deposition center of the lake has not obviously moved, staying along the Huachi-Yijun belt. The deep lake sedimentary system mainly consists of deep water deltas and turbidite fans during the entire evolution course of the lake basin in the Late Triassic. The former mainly developed on the slope of steep shore of the delta in the early period of the deep-water expansion and gradually experienced a big shift from deep-water deltas to shallow-water platform delta. And the latter appeared almost in all the above stages and had two types of turbidite fans, slope-moving turbidite fans and slump turbidite fans. The slope-moving turbidite fans have relatively complete facies belts overlapping one another vertically and consist of the slope channel of inter fans, the turbidite channel, inter turbidite channel and turbidite channel front of middle fans and outer fans (or lakebottom plain). However, the slide-moving turbidity fans are formed in the deep lake with their microfacies difficult to be distinguished, and only the center microfacies and edge microfacies can be determined. The two types of the turbidity fans are similarly distributing in the near-root-slope and far-root-slope regions. The deep-lake deposition governs the distribution of the hydrocarbon and reservoir, while the slope-moving turbidite fans are excellent reservoirs for oil-gas exploration due to their great thickness, widespread distribution and accumulation properties.

  12. Provenance for the Chang 6 and Chang 8 Member of the Yanchang Formation in the Xifeng area and in the periphery Ordos Basin: Evidence from petrologic geochemistry

    LUO; JingLan; LI; Jian; YANG; BingHu


    Study indicates that the major paleocurrent and source direction for the Chang 8 Member of the Yangchang Formation, Upper Triassic in the Xifeng area of the southwestern Ordos Basin derived from the southwest direction with the southeast source as the subordinate one. While the Chang 6 Member was influenced not only by the same source as that of the Chang 8 Member from the southwest and the southeast direction, but also affected by the northeast and the east provenance around the Ordos Basin, based upon measurement of paleocurrents on outcrops located in the periphery Ordos Basin, analysis of framework grains and heavy minerals in sandstones of the Chang 6 and Chang 8 Members and their spatial distribution in the study area, combined with characteristics of trace elements and rare-earth elements of mudstones and of a small amount of sandstones in the Xifeng area and outcrops in margin of the Ordos Basin. The Yuole-Xuanma-Gucheng-Heshui-Ningxia region located in the northeastern and the eastern Xifeng area was the mixed source area where the southwest, southeast, northeast and the east sources were convergent till the Chang 6 Member was deposited. The rare earth elements of the Chang 6 and Chang 8 Members are characterized by slight light rare earth-elements (LREE) enrichment and are slightly depleted in heavy rare earth-elements (HREE) with weak to moderate negative abnormal Eu, resulting in a right inclined REE pattern, which implies that the source rocks are closely related with better differential crust material. Analysis on geochemical characteristics of the mudstones and sandstones, features of parent rocks in provenance terranes and tectonic settings shows that source rocks for the Chang 8 Member mainly came from metamorphic and sedimentary rocks in transitional continental and basement uplift terranes with a small amount of rocks including metamorphic, sedimentary and igneous rocks coming from mixed recycle orogenic belt located in the southwest margin of

  13. 鄂尔多斯盆地富县—正宁地区延长组油气成藏期次%Classification of hydrocarbon accumulation phases of the Yanchang Formation in the Fuxian-Zhengning area, Ordos Basin

    梁宇; 任战利; 史政; 赵筱燕; 于强; 吴晓青


    鄂尔多斯盆地富县—正宁地区延长组砂岩储层主要成岩作用有压实作用、胶结作用、溶蚀作用和裂隙作用,成岩自生矿物以绿泥石、自生石英和方解石为主.根据油气包裹体寄主成岩矿物的形成时间序列,识别出两期油气包裹体:第1期油气包裹体主要分布在石英、长石粒内愈合的、未切穿次生加大边的微裂隙及石英次生加大边内侧;第2期油气包裹体分布在晚期微裂隙和晚期亮晶方解石胶结物中.油气包裹体均一温度分布呈双峰型:早期峰值温度为110~120℃;晚期峰值温度为140~150℃.对油气包裹体均一温度、盐度、密度分析表明,研究区延长组油气为“一期两幕”成藏,且具有“边致密,边成藏”的特点.结合研究区延长组热演化史及储层伊利石K-Ar同位素定年结果研究表明,研究区主要油气成藏期为早白垩世(距今95~120Ma).%The main diagenesis of the Yanchang Formation sandstone reservoirs in the Fuxian-Zhengning area, Ordos Basin, includes compaction, cementation, corrosion and fracturation, and diagenetic authigenic minerals in these reservoirs are dominated by chlorite, authigenetic quartz and calcite. Two phases of hydrocarbon inclusions have been identified according to the time sequence of the formation of host diagenetic minerals, the earlier one composed of mostly brine inclusions that contain gaseous or liquid hydrocarbons either occurs along healed microfractures wrapped up by secondary growth edges of quartz or feldspar, or is trapped at the bottom of secondary growth edges of quartz or feldspar, while the later one mostly consisting of gas-liquid or liquid hydrocarbon inclusions occurs along the late-formed microfractures or in sparry calcite cements. Homogenization temperatures measured from brine inclusions associated with hydrocarbon ones show a bimodal distribution in the ranges with 110~120'C and 140~150'C as peak temperatures

  14. 鄂尔多斯盆地延长组下组合油气来源及成藏模式%Hydrocarbon origin and reservoir forming model of the Lower Yanchang Formation, Ordos Basin

    李相博; 刘显阳; 周世新; 刘化清; 陈启林; 王菁; 廖建波; 黄军平


    通过生物标志化合物对比、流体包裹体分析及盆地模拟研究,对鄂尔多斯盆地延长组长9与长10油层组的油源、成藏期次及成藏模式进行了探讨.陇东与姬塬地区长9油层组的原油分为2种类型,第Ⅰ类来源于长7烃源岩,第Ⅱ类来源于长9烃源岩;陕北地区长10油层组的原油主要来源于长9烃源岩.陇东与姬塬地区长9油藏均发生过2期油气充注,但前者在第1期(中侏罗统直罗组沉积期)就达到了油气充注的高峰期,而后者在第2期(下白垩统志丹组沉积期)才达到油气充注高峰期;陕北长10油层组也存在2期成藏,但2期油气呈连续充注,大致从中侏罗统直罗组沉积早期一直持续到下白垩统志丹组沉积中后期.长9与长10油藏有“上生下储”、“侧生旁储”及“自生自储”3种成藏模式.图10参22%According to the comparison of biomarkers in source rocks and crude oil, fluid inclusion analysis, and basin modeling, this paper discusses the oil source, hydrocarbon accumulation period and reservoir forming model of the Chang 9 and Chang 10 oil-bearing formations, Yanchang Formation, Ordos Basin. The crude oil of Chang 9 in the Longdong and Jiyuan areas can be divided into two types, type I crude oil originated from the source rocks within Chang 7, while type II crude oil came from the source rocks within Chang 9. The crude oil of Chang 10 in Northern Shaanxi originated mainly from the source rocks of Chang 9. The Chang 9 oil reservoirs in both the Longdong and Jiyuan areas experienced two periods of hydrocarbon injection. The former reached the peak period of hydrocarbon injection in the first period (the depositional period of Middle Jurassic Zhiluo Formation), while the latter in the second period (the depositional period of Lower Cretaceous Zhidan Formation). There are two periods of continuous hydrocarbon injection in Chang 10 of Northern Shaanxi, generally from the early depositional period of

  15. Diagenesis and diagenetic facies of low porosity and permeability sandstone in Member 8 of the Yanchang Formation in Daijiaping area, Ordos Basin%鄂尔多斯盆地代家坪地区延长组8段低孔渗砂岩成岩作用及成岩相

    周翔; 何生; 陈召佑; 王芙蓉; 周思宾; 刘萍


    上三叠统延长组长8段砂岩是鄂尔多斯盆地代家坪地区重要的勘探目的层,以长石岩屑细砂岩和岩屑长石细砂岩为主,目前处于中成岩A期,属典型低孔特低渗储层.强烈的成岩作用是储层致密化的主要原因,其中压实作用和碳酸盐岩胶结作用造成储层原生孔隙大量丧失,绿泥石胶结和长石溶蚀对储层物性改善起到了积极作用,碱-酸-碱交替的成岩介质环境变化控制了粘土矿物形成、碳酸盐胶结物沉淀以及长石溶蚀作用.综合多项定性和定量参数,将长8段砂岩划分为5种成岩相类型,定量计算不同成岩相埋藏过程中孔隙演化表明,由沉积作用形成的不同成岩相中砂岩原始组分差异是导致胶结类型和溶蚀程度差异的物质基础,不同成岩相中成岩作用类型及强度是造成砂岩孔隙演化及物性差异的主要原因.优质砂岩储层分布与成岩相密切相关,其中分布于水下分流河道砂体中的弱压实绿泥石胶结相和中压实次生溶蚀相砂岩物性最好,是研究区长8段砂岩储层中最有利的成岩相带.%Member 8 sandstone of the Upper Triassic Yanchang Formation is the major exploration target in Daijiaping area , Ordos Basin .Member 8 sandstone of the Yanchang Formation mainly consists of feldspathic litharenite and lithic arkose , currently is at the A phase of middle diagenesis stage ,and is categorized into low-porosity and extremely low-permeability reservoir .The intensive diagenesis is main cause of reservoir densification .Compaction and carbonate cementation largely reduce the primary porosity ,while chlorite cementation and feldspar dissolution improve the reservoir quality ,and the alka-line-acidic-alkaline change of digenetic environment control the formation of clay mineral ,the precipitation of carbonate ce-ments,and the dissolution of feldspar .Five types of diagenetic facies are identified in the Member 8 sandstone of the Yan-chang

  16. Hydrocarbon Accumulation Models and the Main Controlling Factors for the Lower Member of the Upper Triassic Yanchang Formation in the Wu-Ding area of the Ordos Basin%鄂尔多斯盆地吴定地区延长组下部油气成藏模式与主控因素

    于波; 周康; 郭强; 白奋飞


    Based on the integrated studies of the sedimentary facies,oil-source correlation,formation pressure structure and homogenization temperatures of fluid inclusions,this paper researches the hydrocarbon accumulation models and the main controlling factors for the lower member of Upper Triassic Yanchang Formation in the Wuqi-Dingbian area of the Ordos Basin.The result shows that the formations Chang 7 and Chang 9 are the two sets of fine source rocks which possess good hydrocarbon generation potential in the region.Oil-source correlation shows hydrocarbon in the Chang 7 and Chang 9 formations mainly derives from the source rock Chang 7 in the Wuqi-Dingbian area,and the Chang 9 formation follows.Hydrocarbon generating pressurization is the main drive force for petroleum migration in the Chang 7 formation of the region.The area with high values in the background of low values in excess pressure difference for Chang 7 and Chang 8 is the main locus for hydrocarbon accumulation in the lower member of the Yanchang formation.The main sedimentary facies of the Yanchang formation in the research region is deltaic front subaqueous distributary channels and debouch bars;which may serve as reservoir space with generally higher porosity and permeability.The Chang 8 and Chang 9 reservoirs are characterized by episodic injection and continuous accumulation,and both of the reservoirs belong to hydrocarbon accumulation assemblages under source rocks.Comprehensive analysis suggests that the distribution of the upper Jurassic reservoirs is mainly controlled by three major factors of near sources,low pressure and good facies.%在综合沉积相、油源对比、地层压力结构、包裹体均一温度等方面的基础上,对鄂尔多斯盆地吴起-定边地区延长组下部油气成藏模式与主控因素进行了研究,认为研究区发育长7和长9两套烃源岩,油源对比显示吴定地区长8、长9油气主要来源于长7烃源岩,长9烃源岩次之;延长组长7生烃

  17. Carbon and oxygen isotopic composition of carbonate cements of different phases in terrigenous siliciclastic reservoirs and significance for their origin: A case study from sandstones of the Triassic Yanchang Formation, southwestern Ordos Basin,China

    WANG Qi; ZHUO Xizhun; CHEN Guojun; LI Xiaoyan


    Early carbonate cements in the Yanchang Formation sandstones are composed mainly of calcite with relatively heavier carbon isotope (their δ18O values range from -0.3‰-0.1‰) and lighter oxygen isotope (their ‰18O values range from -22.1‰--19.5‰). Generally, they are closely related to the direct precipitation of oversaturated calcium carbonate from alkaline lake water. This kind of cementation plays an important role in enhancing the anti-compaction ability of sandstones, preserving intragranular volume and providing the mass basis for later dissolution caused by acidic fluid flow to produce secondary porosity. Ferriferous calcites are characterized by relatively light carbon isotope with δ13C values ranging from -8.02‰ to -3.23‰, and lighter oxygen isotope with δ18O values ranging from -22.9‰ to -19.7‰, which is obviously related to the decarboxylation of organic matter during the late period of early diagenesis to the early period of late diagenesis. As the mid-late diagenetic products, ferriferous calcites in the study area are considered as the characteristic authigenic minerals for indicating large-scaled hydrocarbon influx and migration within the clastic reservoir. The late ankerite is relatively heavy in carbon isotope with δ13C values ranging from -1.92‰ to -0.84‰, and shows a wide range of variations in oxygen isotopic composition, with δ18O values ranging from -20.5‰ to -12.6‰. They are believed to have nothing to do with decarboxylation, but the previously formed marine carbonate rock fragments may serve as the chief carbon source for their precipitation, and the alkaline diagenetic environment at the mid-late stage would promote this process.

  18. Reservoir sandstones and their physical properties of the Chang-6 oil measures in the Yanchang Formation, Huaqing region, Ordos Basin%华庆地区延长组长6油层组储集砂岩特征及对储层物性的影响

    苏楠; 隆昊; 田景春; 王卫红; 张锦泉


    长6油层组储集砂岩主要为岩屑长石砂岩,粒度较细,分选中等偏差,填隙物主要为碳酸盐矿物和粘土矿物.砂岩的物质组成影响着其储层性能,储层物性随着石英含量的增加而变好,而随着岩屑含量的增加而变差.砂岩中长石的溶蚀作用是改善储层物性的关键因素.填隙物的含量越大,则孔隙喉道堵塞和充填的程度增加,导致储层物性变差.%The emphasis of this study is placed on the types and characteristics of the reservoir sandstones and their bearings on physical properties of the Chang-6 oil measures in the Yanchang Formation, Huaqing region, Ordos Basin. The reservoir sandstones are represented by lithic feldspathic sandstone with finer grain sizes and moderate to poor sorting. The interstitial materials contain carbonate minerals and clay minerals. The physical properties of the reservoir sandstones are progressively getting better in response to the increase of quartz contents, while worse with the increase of lithoclastic contents. The dissolution of feldspar from the sandstones is believed to be a key factor for the improvement of the physical properties. The higher contents of the interstitial material give rise to the plugging and filling of pore throats, and thus result in the deterioration of the physical properties.

  19. The shale gas resources estimation: An example from Mesozoic Triassic Yanchang Formation Member Chang 7, Ordos Basin%页岩气资源量计算:以鄂尔多斯盆地中生界三叠系延长组长7为例

    王凤琴; 王香增; 张丽霞; 刘洪军; 雷宇


    鄂尔多斯盆地三叠系延长组长7暗色泥页岩是重要的烃源岩.最近的勘探表明,长7具有良好的页岩气开发前景.重点利用鄂尔多斯盆地279口测井资料、18口取心井的347块岩样实验室多种分析测试资料,开展了鄂尔多斯盆地中生界延长组长7页岩气的岩性、岩相、孔隙类型、有机碳含量、热演化程度、含气性、气体储存方式及其在测井曲线的反响研究;在页岩气形成条件的研究基础上,建立了岩性、含气性、有机质含量与自然伽马、声波时差、电阻率之间的关系,有效地识别含气泥页岩;选择容积法对延长组页岩气资源量进行计算,为未来页岩气的勘探和开发奠定基础.%The Mesozoic Triassic Yanchang Formation Chang 7 shale in Ordos Basin is an important hydrocarbon source rock and recently has developed into a very active point in shale gas exploration.The goal of the study is to estimate the shale gas resources.On the basis of 279 wells logging data,geological and geochemical database consisting of 347 core samples from 18 core wells of this area,we conducted an overall analysis of lithology,petrofacies,porosity,total organic carbon (TOC) content,thermal maturity and gas content for the Chang 7 gas shale and studied the response of logging curves to the patterns of gas reservoir.On the basis of the study of the forming conditions of the gas shale the present paper builds up the quantitative relationship between TOC and logging data,including acoustic time logging,natural gamma ray logging and resistivity logging.We use volumetric method to estimate the shale gas resources.The results will lay a foundation for the exploration and exploitation of shale gas in the future.

  20. 鄂尔多斯盆地吴堡地区延长组长8致密砂岩油藏成藏主控因素%The distribution of Chang-8 tight sandstone oil reservoir of Yanchang Formation in Wubao area, central-south of Ordos Basin

    白玉彬; 罗静兰; 王少飞; 杨勇; 唐乐平; 付晓燕; 郑卉


    鄂尔多斯盆地三叠系延长组长8油层组为近年来发现的勘探开发新层系,勘探实践证实其成藏条件优越,勘探潜力大.本文以盆地中南部志丹县吴堡地区为例,对该区长8油藏成藏条件及分布规律进行了研究,结果表明:长8油藏油源主要来自于上覆长73烃源岩、长8内部烃源岩和长9顶部烃源岩,具有良好的生储层组合配置;主成藏期运移动力主要为生烃增压等形成的异常高压,油气充注到长8致密储层后主要以近距离垂向和侧向运移为主;成岩作用加剧了储层非均质性,形成成岩遮挡型准连续型油气聚集.长8油藏平面及层位分布主要受控于有效烃源岩展布、储层质量和有效盖层的控制,多种地质因素共同形成现今长8油藏分布格局.%Chang-8 oil-bearing bed of Yanchang Formation was found in recent years in the exploration and development of new Triassic reservoirs in Ordos Basin.Exploration practice has proved that it has good accumulation conditions and favorable exploration potential.With Wubao area in Zhidan County in the central south part of the basin as an example,the authors studied the conditions and distribution regularity of Chang-8reservoir,and the results show that the Chang-8 oil source mainly came from the overlying Chang-73 source rocks,Chang-8 internal hydrocarbon source rocks and Chnag-9 top hydrocarbon source rocks,thus having a good oil-generating and oil-accumulating reservoir configuration.The migration force of main reservoirproducing stage resulted mainly from hydrocarbon generation pressurization and abnormal high pressure,and the injection of oil and gas into Chang-8 tight reservoir was mainly caused by nearly vertical and lateral migration.Diagenesis exacerbated the reservoir heterogeneity and resulted in the formation of diagenetic occlusion type and quasi-continuous type oil gas accumulations.Chang-8 reservoir plane and horizontal distribution are mainly controlled by

  1. Geochemical Characteristics of Crude Oil and Oil-Source Correlation in Yanchang Formation(Upper Triassic) in Wubao Area, Ordos Basin%鄂尔多斯盆地吴堡地区上三叠统延长组原油地球化学特征及油源对比

    白玉彬; 罗静兰; 刘新菊; 靳文奇; 王小军


    鄂尔多斯盆地延长组油源一直存在争议,尤以长8~长10油藏的油源问题最为突出.通过吴堡地区延长组长6~长10原油的物理性质、族组成、生物标志化合物等特征,油一油、油一源对比等综合分析,探讨延长组原油的成因,明确各油层组石油来源,为该区的油气勘探与预测提供地质依据.结果显示,长6 ~长 10原油族组分具有饱和烃含量最高,芳香烃次之,非烃和沥青质含量最低的特征.长6 ~长10均为成熟原油,显示出低等水生生物和高等植物混合成因,但长6原油与长7 ~长10原油族组成特征存在明显差异.长6原油为长7烃源岩早期烃类运移的结果,其成熟度最低,长7~长10原油为生烃高峰阶段石油运移结果,成熟度较高.长6和长7油藏的原油主要为长7底部张家滩页岩贡献,此外,长7中上部和长6地层中发育的有效烃源岩也有一定贡献.长8油藏原油为混合成因原油,主要为长7底部烃源岩向下运移结果,其次为长8内部烃源岩和长9顶部李家畔页岩之贡献.长9油藏原油主要为李家畔页岩向下倒灌形成,长10油藏可能主要为长92有效烃源岩向下运移成藏.热成熟度不同是导致远离主力烃源岩原油族组分之间差异性的主要原因.%The oil sources in the Yanchang Formation of the Ordos Basin has always been controversial, especially in the reservoir Chang-8 to Chang-10. According to the crude oil of Chang-6 to Chang-10 of Yanchang Formation in Wubao area, the article discusses the physical properties, the group composition, the biomarkers, and the oil-oil and oil-source correlation in terms of their geneses and the origin of petroleum in respective reservoirs so as to provide the geological basis for the area's petroleum exploration and prediction. The result shows that the group composition of Chang-6 to Chang-10 is characterized by the highest content of the saturated hydrocarbon, which follows the

  2. Microscopic pore structure of the fourth and fifth members of the Yanchang Formation in Zhenbei area of the Ordos Basin%鄂尔多斯盆地镇北地区长4+5储层微观孔隙结构研究

    李成; 郑庆华; 张三; 柳益群; 汪伶俐; 梁晓伟


    The fourth and fifth members of the Yanchang Formation ( Chang4+5) in Zhenbei area of the Ordos Basin are low⁃permeability reservoirs of diagenetic origin. Conventional methods such as thin section analysis, scanning electron microscopy and physical properties determination failed to analyze the microscopic pore struc⁃ture of these reservoirs. We used conventional methods and applied constant rate mercury penetration to study the controlling factors to quantitatively determine microscopic pore structure. The microscopic pore structure of the Chang4+5 reservoirs was mainly impacted by diagenetic effects. When mechanical compaction and carbonate cementa⁃tion were weaker and feldspar dissolution was more intense, intergranular pores and dissolution pores would be more developed, resulting in better connectivity and higher permeability. Microscopic pore structure and permeability were mainly controlled by throat radius. Generally, if average throat radius was >0.12μm, permeability would be higher, the smaller the pore/throat radius ratio, the better the microscopic pore structure, the greater the reservoir quality index ( RQI) , and the higher liquid oil yield, especially when the average throat radius was <1.26μm. Throats controlled the quality of the microscopic pore structure of low permeability reservoirs.%鄂尔多斯盆地镇北地区延长组长4+5以成岩型低渗透储层为主,常规方法较难评价该类储层微观孔隙结构品质。利用铸体薄片、扫描电镜和物性分析等方法对影响储层微观孔隙结构特征的因素进行了定性分析,恒速压汞方法对储层微观孔隙结构特征参数进行了定量表征。研究表明:镇北地区长4+5低渗透储层微观孔隙结构与成岩作用密切相关,主要表现为机械压实作用和碳酸盐胶结作用越弱,长石溶蚀作用越强烈,粒间孔和溶蚀孔越发育,孔喉连通性越好,渗透率越大;微观孔

  3. Quantitative simulation of sandstone porosity evolution:A case from Yanchang Formation of the Zhenjing area,Ordos Basin%砂岩孔隙度演化定量模拟方法——以鄂尔多斯盆地镇泾地区延长组为例

    潘高峰; 刘震; 赵舒; 胡宗全; 胡小丹


    The present paper presented a newly developed quantitative simulation for sandstone porosity evolution. The methodology was based on burial history and diagenetic history of strata. The impact of both destructive and constructive diagenesis on porosity was taken into account. With effect-oriented simulation as the principle, geological time as the variable, and current porosity as boundary contraint conditions, the porosity evolution was divided into two independent processes: porosity decrease and porosity increase, for which two mathematical models were built, respectively. Then, a mathematical model was established based on the superimposition of two types of porosity evolution processes. This porosity evolution model was characterized by: 1) time as the variable that reflected the dynamic process of porosity evolution; 2) current porosity as boundary constraint conditions whose results were reliable; 3) full consideration of the impact of compaction, cementation and secondary dissolution. The mode was applied to simulating the porosity evolution of the Member 8 of the Yanchang Formation in the Zhenjing area in the Ordos basin, and it was found that the decrease in porosity was a continuous function of burial depth and burial time; and that the secondary porosity was caused by organic acid dissolution within a temperature window of 70℃ ~ 90℃. The porosity increase included three stages: pre-porosity increase, porosity increase under temperature window conditions, and secondary porosity preservation. The total porosity evolution model built from the superimposition of porosity decrease and increase was a piecewise function with three sections. The application of this approach indicated that it could be widely used in paleoporosity restoration and porosity evolution simulation.%在地层埋藏史和成岩史研究的基础上,综合考虑破坏性成岩作用和建设性成岩作用对孔隙度的影响,按照效应模拟原则,以现今孔隙度特征为

  4. Palynology of Yanchang Formation of Middle and Late Triassic in Eastern Gansu Province and Its Paleoclimatic Significance

    Ji Liming; Meng Fanwei


    Xifeng (西峰) oilfield was recently found in the southwest of the Ordos basin. The oil source rocks are the Chang 7 Section of Yanchang (延长) Formation. In order to study the paleoclimate that controlled the formation of source rocks, a systemically palynological research on related beds in Yanchang Formation has been carried out. The core samples were analyzed with classical palynological techniques and the organic-walled sporomorphs from these samples were observed, identified and photographed under a light microscopy and a fluorescence microscopy. Abundant sporopollen were found in drilling cores from Chang 8 and Chang 7 sections, and two assemblages were distinguished: the Aratisporites-Punctatisporites assemblage and the Asseretospora-Walchiites assemblage. Their characteristics are similar to those of the assemblage of Tongchuan (铜川) Formation and the assemblage of Yanchang Formation in southeast Ordos basin, respectively. Their geological times are Ladinian of late Middle Triassic and Carnian of early Late Triassic, respectively. The correlation of palynoflora with their parent plants suggests the paleoclimate of eastern Gansu (甘肃) Province in the Middle and Late Triassic was warm and rainy with prosperous vegetation. The palynoflora indicated the area was in a temperate to subtropical zone then. Both the ecological types and differentiation degree curves of sporopollen indicated the period during Chang 8 and Chang 7 sections was warm and wet, and the phase accorded with large-scale lake transgression in Chang 8 Section and the largest lake area in Chang 7 Section. North China in Middle and Late Triassic was located in a warm and rainy, temperate and subtropical zone. The palynofloras in Chang 8 and Chang 7 sections have the characteristics of North China flora, however they also indicate wetter and warmer climate due to their proximity to the large lakes. The period of Chang 8 to Chang 7 sections is the climax of the expansion of the lake, and

  5. The Reservoir Characteristics of Chang 8 Oil Layer Group From the Yanchang Formation in Zhenjing Area, Ordos Basin%鄂尔多斯盆地镇泾区块延长组长8油层组砂岩储层特征

    张霞; 林春明; 陈召佑; 潘峰; 周健; 俞昊


    The Chang 8 sandstones of the Yanchang Formation in Zhenjing area of Ordos Basin, occurring as one of the major reservoirs, mainly consist of feldspathic litharenite and lithic arkose. They belong to extra-low porosity and permeability reservoirs, with dissolved intergranular pores as the chief accumulation space, and the reduced-neck, lamellar and curved lamellar pore throat as the main throat type. Based on the pattern of capillary pressure curve, porosity, permeability, displacement pressure and pore throat radius, the Chang 8 sandstones can be classified as type I, II and III, in which the type II are the main reservoirs. There are four factors affecting the reservoir characteristics of Chang 8 sandstones: sedimentary processes, diagenesis, fractures, and hydrocarbon emplacement. The best reservoir quality is developed in the subaqueous distributary channels of braided river delta fronts, and the one of medium sandstones hetter than that of fine sandstones. Otherwise, the reservoir qualifies of sandstones rich in quartz, feldspars and metamorphic rock fragments are better than those of sandstones with high contents of sedimentary and igneous rock fragments, as well as mica. The diagenetic processes have exerted dual impacts on the reservoir quality. The constructive one is characterized by dissolution and pore-lining chlorite cementation, and the sandstone intervals with them occurring together are the optimum zones for the oil and gas accumulation. The destructive one involves mechanical compaction and the late stage carbonate cementation. The fractures, with the NE-SW tectonic ones formed in the late stage of Cretaceous-Paleogene as the main type, contribute more to permeability than storage, making the heterogeneity of reservoirs intensified. The effects of hydrocarbon emplacement on reservoir quality are characterized by the reconstruction and conservation of porosity dissolved by organic acid in hydrocarbon.%延长组长8油层组是鄂尔多斯盆地镇

  6. Quantitative Simulation on Porosity-evolution in Member 8 of Yanchang Formation of Baibao-Huachi Area,Ordos Basin%鄂尔多斯盆地白豹—华池地区长8段孔隙度演化定量模拟

    姚泾利; 唐俊; 庞国印; 马晓峰; 王琪


    在对鄂尔多斯盆地白豹-华池地区长8段砂岩储层特征、主控因素分析及地层埋藏史和成岩史研究的基础上,应用数理统计的方法,以现今孔隙度为约束条件,将孔隙度演化分为孔隙度减小和孔隙度增大2个过程,分别建立了鄂尔多斯盆地白豹-华池地区长8段砂岩储层从埋藏初始至现今的孔隙度随埋藏深度和地史时间变化的演化模型.结果表明:孔隙度定量演化模型为一个4段式分段函数.机械压实阶段为孔隙度减小模型,是以埋深为自变量的连续函数;压实和胶结作用阶段为孔隙度减小模型,是对埋深和埋藏时间的连续函数;次生增孔是由于地层酸性流体的溶蚀作用而产生的,主要发生在80~100℃的温度窗口内.因此,溶蚀阶段为孔隙度增大模型,是对埋深和埋藏时间的复合函数;溶蚀阶段结束后地层孔隙度为压实和保持阶段,孔隙度减小模型是对埋深、埋藏时间及增孔量的叠加复合函数.实例验证结果表明在研究区建立的该砂岩孔隙度定量演化模型符合地质实际,可以推广应用到研究区相似岩性、埋藏年代和沉积类型的地层孔隙度计算中,为孔隙度预测提供定量计算方法,以期对该区油气勘探提供借鉴意义.%Combining with the mathematical statistics method,we describe of tight sandstone reservoir characteristics and simulate the burial history and diagenetic history of the Member 8 of Yanchang Formation in the Baibao-Huachi area,Ordos basin. According to present porosity as boundary constraint conditions,geological times and burial depths,the whole porosity evolution from initial burial until present is divided into two independent processes of porosity decrease and porosity increase and establish two mathematical models, respectively. The quantitative simulation result indicates that the whole porosity-evolution quantitative simulation is a piecewise function with four sections

  7. 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


    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.

  8. Albitization and hydrothermal diagenesis of Yanchang oil sandstone reservoir,Ordos Basin%鄂尔多斯盆地三叠系延长组砂岩钠长石化与热液成岩作用研究

    李荣西; 段立志; 陈宝赟; 夏冰; 李靖波


    鄂尔多斯盆地延长组储层砂岩发育大量自生钠长石矿物,其成因和产出与浊沸石有关,含量和分布比浊沸石多而广泛,但没有引起人们的注意.大量详细岩相学观察发现延长组储层砂岩发育丰富的自生钠长石,其主要为由斜长石碎屑蚀变形成或呈胶结物充填分布在砂岩碎屑颗粒之间.钠长石中含有大量原生的发亮黄色荧光的油气包裹体,表明其形成与油气注入同时.电子探针成分分析表明,钠长石Na2O含量较高,几乎为斜长石的纯钠长石端员(NaAlSi3O8),没有钙长石端员(CaAl2Si2O8).激光拉曼光谱特征反映出钠长石为沉积成岩期形成的低温钠长石,而非来源于岩浆岩或者变质岩区的碎屑钠长石.应用LA-MC-ICP/MS原位微分析技术对钠长石进行的稀土元素分析表明,延长组砂岩钠长石具有热水成岩作用地球化学特征,属于热液成岩作用产物.认为大量钠长石形成与石油充注的同时进行导致了储层致密过程中岩性油藏的形成.延长组储层砂岩中热液成岩作用对油藏形成和分布意义重大,值得重视和研究.%The Triassic low permeability reservoir sandstone of Yanchang Formation in Ordos Basin is composed of fine-grained arkose and feldspathic litharenite. Lots of research work has been devoted to the diagenesis of reservoir sandstone of Yanchang Formation. It is considered that the formation of secondary pore through dissolution of laumontite improved the reservoir property of sandstone, and the dissolution of laumontite was closely related to alteration of plagioclase. According to the equilibrium theory of mineral reaction, the laumontite formed by the alteration of plagioclase accompanied by the formation of albite is two times as many as the laumontite in quantity. Therefore, if laumontite of sandstone in Yanchang Formation was dissolved to form dissolution pores, the content of albite with more stability should be higher in theory

  9. A study of the accumulation periods of low permeability reservoir of Yanchang Formation in Longdong Area, Ordos Basin%鄂尔多斯盆地陇东地区延长组低渗透油藏成藏期次研究

    付金华; 柳广弟; 杨伟伟; 冯渊; 张雪峰; 程党性


    The hydrocarbon accumulation time of Yanchang Formation in Longdong Area is determined according to the characteristics of fluid inclusion, combined with the hydrocarbon generation history of source rock and oil maturity. The characteristics of fluid inclusion under microscope and UV fluorescence suggest that there are two periods of hydrocarbon inclusion. The first stage of hydrocarbon inclusion is dust or dark brown liquid hydrocarbon inclusion under polarized light microscope, its abundance is low, and the homogenization temperature of accompanied saline inclusions is 75 - 95℃. The second stage of hydrocarbon inclusion is mainly gas and liquid hydrocarbon inclusion, the liquid is colorless or light yellow under polarized light microscope and light yellow to bluish green under fluorescence microscope, its abundance is high, and the main peaks of homogenization temperature of accompanied saline inclusions are 75 - 95℃ and 100 - 120℃. Three periods of hydrocarbon accumulation are showed: the early period of low mature oil charging in a small scale at 140 - 130 Ma, the middle period of mature oil accumulating in a large scale at 120 - 100 Ma corresponding to the peak of hydrocarbon generation, and the late period of adjusting accumulation at 100 - 40 Ma.%主要对陇东地区延长组流体包裹体特征进行了研究,结合烃源岩生烃史、原油成熟度,综合分析研究区的成藏期次.流体包裹体镜下观察与荧光特征显示陇东地区延长组存在两期油气包裹体:第一期油气包裹体在单偏光下呈灰褐色或深褐色的液烃包裹体,丰度较低,盐水包裹体均一温度主峰为75~95℃;第二期油气包裹体以气液烃包裹体为主,液烃表现为无色或淡黄色的单偏光特征与浅黄色至蓝绿色的荧光特征,丰度较高,盐水包裹体均一温度主峰为75~95℃与100~120℃.结合烃源岩生烃史与原油成熟度认为,陇东地区延长组存在三期成藏:距今约为140~130Ma

  10. Diagenesis and porosity evolution of tight sand reservoirs in Carboniferous Benxi Formation, Southeast Ordos Basin

    Hu, Peng; Yu, Xinghe; Shan, Xin; Su, Dongxu; Wang, Jiao; Li, Yalong; Shi, Xin; Xu, Liqiang


    porosity caused by different diagenesis reveals that mechanical compaction and chemical cementation are the main mechanisms for destroying primary pores, which contribute 19.61% and 8.75% to the loss of primary posoity, respectively. Dissolution of volcanic fragments and feldspar increased reservoir porosity by 4.14%. The pores were occluded by late minerals and carbonate cements, resulting in a reduction of 9.38%. Overall, the dual influence of compaction and cementation is the key of the key, controlling formation of tight gas sandstone reservoirs. Keywords: diagenesis, porosity evolution, tight sandstone, Benxi Formation, Southeast Ordos Basin Acknowledgements: We greatfully acknowledge Yanchang Petroleum for providing the samples and data access and for permission to publish this work. The first author, Peng Hu, would like to thank the support from Prof. Xinghe Yu.

  11. The accumulation mechanism and accumulation models of oil in low permeability reservoir of Yanchang Formation in Longdong Area, Ordos Basin%鄂尔多斯盆地陇东地区延长组低渗透砂岩油藏成藏机理与成藏模式

    杨伟伟; 柳广弟; 刘显阳; 冯渊; 独育国; 程党性


    Low permeability oil reservoirs are widely distributed all over the world, which are important for petroleum exploration and development in the future. The characteristics of low permeability sandstone oil reservoirs are as follows: the oil saturation is low and its relationship with reservoir physical properties is complex; the oil-water relationship is very complicated with unobvious oil-water interface; the reservoirs are widely distributed without control of structures; and the farther from the sources, the poorer is the oil enrichment. The accumulation mechanism of low permeability reservoirs was analyzed through the study of accumulation process of Yanchang Formation reservoirs in Longdong Area. It is showed that the displacement pressure of low permeability reservoirs is high and the buoyancy force is very limited in low permeability sandstones without fractures, and hydrocarbons charge into adjacent sandstones forming primary reservoirs driven by the excess pressure from hydrocarbon generation of high-quality source rocks. When fractures develop, hydrocarbons migrate vertically and laterally driven by the buoyancy force and accumulate at the sandstones far away from the source rocks, forming secondary reservoirs. Three models of hydrocarbon accumulation were established based on the analysis of hydrocarbon accumulation periods, characteristics and forming time of fractures, pore evolution history and reservoir forming dynamics. They are low mature oil charge in a small scale at the early stage, mature oil charge and accumulation in a large scale at the middle stage, and adjusting accumulation of tectonic uplift at the late stage. Furthermore, the main controlling factors of low permeability oil reservoirs were expounded on the basis of the above studies. The source rocks are in close proximity to sandstone reservoirs, which lay the foundation of oil enrichment. The distribution of primary reservoirs is controlled by the generation and expulsion of high


    廖朋; 唐俊; 庞国印; 唐丽; 马晓峰; 王琪


    长81油层是鄂尔多斯盆地姬塬地区勘探潜力较大的含油层位之一.通过10口井的岩心观察,63个铸体染色薄片的鉴定、7个样品的扫描电镜观察、32个样品的薄片鉴定报告和44口井的岩心分析数据的统计等方法,对鄂尔多斯盆地姬塬地区延长组长81段储层进行研究,结果表明:研究区储层孔隙类型以粒间孔为主,偶见次生溶孔,其平均孔隙度为7.81%,平均渗透率为0.26×10-3μm2,总体表现为低孔、低渗特征.沉积条件是储层原始矿物成分和岩石结构形成的基础,它使得分流河道、水下分流河道、河口坝和远砂坝4个微相的储层原始物性产生了一定的差异.成岩作用是影响储层物性好坏的关键因素,其中压实和碳酸盐、硅质、高岭石胶结使得原始孔隙度平均损失分别达23.15%和13.22%;绿泥石薄膜对储层物性有一定的积极作用;溶蚀作用对储层物性的改善有限,孔隙度增加平均只有0.58%,其重要原因是研究区异常热演化史导致早期碳酸盐胶结物后期不被溶蚀.%The Chang 8, reservoir is one of the oil stratigraphic horizons with great exploration potentiality in Jiyuan region of the Ordos basin. This reservoir is investigated by analysis of lithol-ogy,thin sections,SEM and core properties. It is showed that the types of pore are mainly interg-ranular pores with minor secondary solution pores,and the reservoir is characterized by low porosity and permeability with average porosity of 7. 81% .average permeability of 0. 26×l0-3 μm2. Sedimentary condition is the basis for the formation of original mineral compositions and rock tex-ture, which plays some control action on reservoir physical property and creates the differences a-mong original reservoir physical property of distributary channel, underwater distributary chan-nel, mouth bar and distal bar. Diagenesis was the key factor affecting reservoir physical property. In fact .compaction

  13. Fluorescence intensity studies of Triassic acritarchs from the Yanchang Formation in Ordos basin,northwestern China

    JI Liming; MENG Fanwei; XU Jinli


    Fluorescence properties of Early Cambrian acritarchs were investigated using Leica das Mikroskop (DM)microscopy with a mercury lamp.Well-preserved autoflurescence properties show a correlation between acritarchs morphology and the intensity of emitted fluorescence.In accordance with the fluorescence intensity of organic cell walls,two groups ofmicrofossils were distinguished.Results of observation in this study,which are consistent with those of the previous foreign studies,are in good agreement with regular difference in autofluorescence intensity among palynomorphs reported by McPhilemy (1998).Spores and algae,including Botryococcus,have very bright fluorescence while acritarchs often show less intense fluorescence.Dark brown microfossils have been reworked,and have little or no fluorescence.

  14. Model building for Chang-8 low permeability sandstone reservoir in the Yanchang formation of the Xifeng oil field

    SONG Fan; HOU Jia-gen; SU Ni-na


    In order to build a model for the Chang-8 low permeability sandstone reservoir in the Yanchang formation of the Xifeng oil field, we studied sedlimentation and diagenesis of sandstone and analyzed major factors controlling this low permeability reser-voir. By doing so, we have made clear that the spatial distribution of reservoir attribute parameters is controlled by the spatial dis-tribution of various kinds of sandstone bodies. By taking advantage of many coring wells and high quality logging data, we used regression analysis for a single well with geological conditions as constraints, to build the interpretation model for logging data and to calculate attribute parameters for a single well, which ensured accuracy of the 1-D vertical model. On this basis, we built a litho-facies model to replace the sedimentary facies model. In addition, we also built a porosity model by using a sequential Gaussian simulation with the lithofacies model as the constraint. In the end, we built a permeability model by using Markov-Bayes simula-tion, with the porosity attribute as the covariate. The results show that the permeability model reflects very well the relative differ-ences between low permeability values, which is of great importance for locating high permeability zones and forecasting zones favorable for exploration and exploitation.

  15. Oil Resources Potential and Exploration of Ordos Basin

    Yang Hua; Luo Anxiang; Fu Jinhua; Xi Shengli


    @@ Ordos Basin has experienced nearly a century of oil-gas exploration since China's first oil exploratory well (Yan-1 well) was drilled in 1907 in Yanchang County, Shaanxi Province. A good prospect for sustained and steady development of oil and gas was thereby opened based on the efforts made by generations of petroleum geologists and oil workers.

  16. Characteristics of hydrocarbon sources and controlling factors of their formation in Pingliang Formation, West Ordos Basin


    According to organic geochemistry and organic petrology, the hydrocarbon sources in Pingliang Formation, W. Ordos basin, are systematically evaluated. The organic abundance of hydrocarbon source in this research is higher in the upper part of profiles than In the low, and more in mudstone than in carbonate. Most of organic matters become sapropelic, and few are humlc-aapropelic in the regions of Shibangou and Zhuzisan. According to stable isotopes of carbon and oxygen in carbonate rock, boron index and ratios of elements, palaeo-salinity and sedimentary velocity are calculated. The two factors of paleao-salinity and sediment velocity, which control the distribution of organic matters, are discussed.Good relationship is found between water salinity and abundance of organic matter; in contrast, poor correlation is observed between salinity and types of organic matters. The relative sediment velocity in the research regions is also related with organic abundance and types. A low sediment velocity would lead to high abundance and good type of organic matters, and vice versa.

  17. Preliminary Simulations of CO2 Transport in the Dolostone Formations in the Ordos Basin, China

    Hao, Y; Wolery, T; Carroll, S


    This report summarizes preliminary 2-D reactive-transport simulations on the injection, storage and transport of supercritical CO{sub 2} in dolostone formations in the Ordos Basin in China. The purpose of the simulations was to evaluate the role that basin heterogeneity, permeability, CO{sub 2} flux, and geochemical reactions between the carbonate geology and the CO{sub 2} equilibrated brines have on the evolution of porosity and permeability in the storage reservoir. The 2-D simulation of CO{sub 2} injection at 10{sup 3} ton/year corresponds to CO{sub 2} injection at a rate of 3 x 10{sup 5} ton/year in a 3-D, low permeable rock. An average permeability of 10 md was used in the simulation and reflects the upper range of permeability reported for the Ordos Basin Majiagou Group. Transport and distribution of CO{sub 2} between in the gas, aqueous, and solid phases were followed during a 10-year injection phase and a 10-year post injection phase. Our results show that CO{sub 2} flux and the spatial distribution of reservoir permeability will dictate the transport of CO{sub 2} in the injection and post injection phases. The injection rate of supercritical CO{sub 2} into low permeable reservoirs may need to be adjusted to avoid over pressure and mechanical damage to the reservoir. Although it should be noted that 3-D simulations are needed to more accurately model pressure build-up in the injection phase. There is negligible change in porosity and permeability due to carbonate mineral dissolution or anhydrite precipitation because a very small amount of carbonate dissolution is required to reach equilibrium with respect these phases. Injected CO{sub 2} is stored largely in supercritical and dissolved phases. During the injection phase, CO{sub 2} is transport driven by pressure build up and CO{sub 2} buoyancy.

  18. Formation Mechanism of the High-quality Upper Paleozoic Natural Gas Reservoirs in the Ordos Basin

    ZHAO Wenzhi; WANG Zecheng; CHEN Menjin; ZHENG Hongju


    The upper Paleozoic natural gas reservoirs in the Ordos basin are generally characterized by a large gas-bearing area and low reserve abundance. On such a geological background, there still exist gas-enriched zones, with relatively high outputs, high reserve abundance and stably distributed gas layers. The gas-enriched layers with relatively high permeability (the lower limit permeability is 0.5×l0-3 μm2) are key factors for the enrichment and high output of natural gas. Based on core observation, analytic results of inclusions, and a great deal of drilling data, we proposed the following four mechanisms for the formation of high-quality reservoirs: (1) in the source area the parent rocks are mainly metamorphic rocks and granites, which are favorable to keeping primary porosity; (2) under the condition of low A/S (accommodation/sediment supply) ratios,sandstone complex formed due to multistage fluvial stacking and filling are coarse in grain size with a high degree of sorting,low content of mud and good physical properties; (3) early-stage recharge of hydrocarbons restricted compaction and cementation, and thus are favorable to preservation of primary pores; (4) microfractures caused by the activity of basement faults during the Yanshan Movement stage can not only improve the permeability of tight sandstones, but also afford vertical pathways for hydrocarbon gas migration.

  19. Soft-sediment deformation structures in cores from lacustrine slurry deposits of the Late Triassic Yanchang Fm. (central China

    Yang Renchao


    Full Text Available The fine-grained autochthonous sedimentation in the deep part of a Late Triassic lake was frequently interrupted by gravity-induced mass flows. Some of these mass flows were so rich in water that they must have represented slurries. This can be deduced from the soft-sediment deformation structures that abound in cores from these lacustrine deposits which constitute the Yanchang Fm., which is present in the Ordos Basin (central China.

  20. Characteristics of NMR Water Displacing Oil and Influencing Factors in Extra-low Permeable Sandstones:Taking the Yanchang Group in Ordos Basin as an Example%特低渗透砂岩的核磁共振水驱油特征及其影响因素--以鄂尔多斯盆地延长组为例


    Samples of Yanchang group in Ordos Basin were tested using the NMR technique before and after the water-looding experiments in order to analyze the characteristics of water displacing oil and to reveal the dominant factors for extra-low permeable sandstones. The results show that oil phase T2 patterns present double peaks in an irreducible water condition with crossing points at about 16.68 ms and movable oil parameters are sensitive to permeability. The right peak decreases to different extents after water-flooding; while the drop of left peak is related to the imbibition of capillary. If the imbibition of capillary can be utilized effectively, recovery can be enhanced. Average value of movable oil percentage is 57.62 and displacement efficiency is 37.33. There is about 20.29% movable oil that has not been flooded out and the development potential is still great after water displacing oil for extra-low permeable sandstones. Physical property, matching relationship of pore throat, degrees of microcrack development, occurrence forms of clay mineral are the main factors affecting displacement efficiency. Correlation between displacement efficiency and movable oil percentage confirms that movable oil percentage of NMR is the upper limit of displacement efficiency.%  为分析特低渗透砂岩的水驱油特征,揭示影响水驱油效果的主要因素,利用核磁共振技术对鄂尔多斯盆地延长组样品进行了水驱油前后的T2谱测试。结果表明,实验样品束缚水状态下的油相T2谱呈双峰形态,两峰之间的交点在16.68 ms左右,可动油参数对渗透率变化敏感;水驱油后T2谱右峰下降程度不同,左峰的下降与毛细管的自吸作用有关,发挥好毛细管的自吸作用,有助于提高采收率。38块样品的平均可动油百分数达到了57.62%,驱油效率为37.33%,还有约20.29%的可动油没有被驱出,水驱油后的开发潜力仍然较大。物性、孔喉匹配关系、

  1. Sedimentology and sequence stratigraphy of Lower Shihezi Formation in Shenguhao area, northern Ordos basin, China

    Chen, Lin; Lu, Yongchao; Lin, Zi


    The structural location of Shenguhao area locates at the transition zone of Yimeng uplift and Yishan slope of northern Ordos basin, China. The study area is in erosion condition until Late Carboniferous and has deposited Taiyuan Formation (C2t), Shanxi Formation (P1s), Lower Shihezi Formation (P1x), Upper Shihezi Formation (P2s) and Shiqianfeng Formation (P2sh) in succession during Late Paleozoic, which mainly develops transition facies and alluvial plain facies. The fluvial sandstone of Lower Shihezi Formation is the major target layer of gas exploration and development in this area. This study is based on the interpretation of 38 wells and 113 sesmic reflection profiles. Three significant lithofacies were identified with sedimentological analysis of cores from the Shenguhao area: fluvial conglomerates, fluvial sandstone and floodplain mudstone, which represent fluvial depositional environment. Based on sequence stratigraphy methodology, well log patterns and lithofacies analysis, Lower Shihezi Formation can be divided into four depositional sequence cycles (1-4) bounded by fluvial scouring erosional surfaces. Each sequence succession shows the trend of base level rising and overall performs fining-upward feature, which characterized by coarsening-upward lower to upper fluvial sandstone and floodplain mudstone. In ascending order, sequence 1 records the transition from the underlying braided river delta plain fine-grained sediments of Shanxi Formation into the overlying fluvial sandstone of Lower Shihezi Formation and develops scouring erosional unconformity at the base, representing a regression. Sequence 1 consists of a package of progradting thick layer of amalgamated fluvial sandstone at the lower part passing into aggrading thin layer of floodplain mudstone at the upper part, suggesting that accommodation growing rate is gradually greater than deposition supply rate under the background of base level gradual increase. Sequence 2 and 3 record similar

  2. Vertical structure and dominating factors of sand body during Late Triassic Chang 9 time of Yanchang Formation in Ordos Basin, NW China

    丁熊; 陈景山; 谭秀成; 林丹; 赵子豪; 姚泾利; 邓秀芹; 李元昊


    Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9 sand body in Odors Basin were recognized, which included two effects, that is, delta environment and tractive current effects that lead to the development of mouth bar, distal bar, sheet sand and other sand bodies of subaerial and subaqueous distributary channel, natural levee, flood fan and delta front, and shore-shallow lake environment and lake flow transformation effects that result in the development of sandy beach bar, sheet sand and other sand bodies. Chang 9 sand body mainly developed five basic vertical structures, namely box shape, campaniform, infundibuliform, finger and dentoid. The vertical stacking patterns of multilayer sand body was complex, and the common shapes included box shape + box shape, campaniform + campaniform, campaniform + box shape, infundibuliform+infundibuliform, campaniform+infundibuliform, box shape+campaniform, box shape+infundibuliform, and finger+finger. Based on the analysis on major dominating factors of vertical structure of sand body, sedimentary environment, sedimentary facies and rise, fall and cycle of base level are identified as the major geological factors that control the vertical structure of single sand body as well as vertical stacking patterns and distribution of multistory sand bodies.

  3. Methylotrophic methanogenesis governs the biogenic coal bed methane formation in Eastern Ordos Basin, China.

    Guo, Hongguang; Yu, Zhisheng; Liu, Ruyin; Zhang, Hongxun; Zhong, Qiding; Xiong, Zhenghe


    To identify themethanogenic pathways present in a deep coal bed methane (CBM) reservoir associated with Eastern Ordos Basin in China, a series of geochemical and microbiological studies was performed using gas and water samples produced from the Liulin CBM reservoir. The composition and stable isotopic ratios of CBM implied a mixed biogenic and thermogenic origin of the methane. Archaeal 16S rRNA gene analysis revealed the dominance of the methylotrophic methanogen Methanolobus in the water produced. The high potential of methane production by methylotrophic methanogens was found in the enrichments using the water samples amended with methanol and incubated at 25 and 35 °C. Methylotrophic methanogens were the dominant archaea in both enrichments as shown by polymerase chain reaction (PCR)–denaturing gradient gel electrophoresis (DGGE). Bacterial 16S rRNA gene analysis revealed that fermentative, sulfate-reducing, and nitrate-reducing bacteria inhabiting the water produced were a factor in coal biodegradation to fuel methanogens. These results suggested that past and ongoing biodegradation of coal by methylotrophic methanogens and syntrophic bacteria, as well as thermogenic CBM production, contributed to the Liulin CBM reserves associated with the Eastern Ordos Basin.

  4. Accumulation patterns of the Chang-9 oil reservoir in the Yanchang Formation of Hongjingzi area in Jiyuan oilfield%姬塬油田红井子地区延长组长9油层组石油富集规律

    陈朝兵; 朱玉双; 谢辉; 张杰; 王海华; 程刚; 徐森


    The paper summarized the hydrocarbon accumulation pattern in the formation based on analysis of logging and core data, relationship among lithology, physical property, electrical property and oil-bearing situation , as well as formation test and production test results from the Chang-9 reservoir in the Yanchang Formation of the Hongjingzi block in Jiyuan oilfield, Ordos Basin. It is suggested that the oil and gas generated in source rocks of the Chang-7 layer were mainly driven by the excess flow pressure inside and migrated to the Chang-9 reservoirs through pores and fractures. However,the hydrocarbon expulsion in Chang-7 was not strong enough to fully fill up the Chang-9 reservoirs. In addition the bottom water widely developed in the Chang-9 reservoirs impeded the further downward migration of hydrocarbons. The top barriers inside the Chang-9 provided the sealing conditions necessary for hydrocarbon accumulation in the reservoirs, resulting in the enrichment of some hydrocarbons in in-terlayers inside the Chang-9. Hydrocarbons might first accumulate in top layers of the Chang-91 where the physical properties were more favorable due to the dual control of lithology and physical properties. The relationship between structure features and formation testing as well as production testing results demonstrates that the structural relief has very little effect on oil and gas accumulations in the Chang-9 reservoirs.%通过测井分析、岩心观察、“四性关系”(岩性、物性、电性、含油性)研究以及试油、试采数据分析,结合构造特征解析,总结了鄂尔多斯盆地姬塬油田红井子地区长9油层组的石油富集规律.长7烃源岩生成的油气以流体过剩压力为主要驱动力,通过孔隙和裂缝运移至长9储层;长7烃源岩排烃强度有限、动力不足,使油气无法完全充满长9储层,而长9内部普遍发育的底水进一步阻碍了油气向下运移;长9顶部稳定发育的隔层为油气聚集提

  5. Features of Mesozoic source rocks and oil-source correlation in southern Ordos Basin%鄂尔多斯盆地南部中生界烃源岩特征及油源对比

    张云霞; 陈纯芳; 宋艳波; 陶冶; 李松


    Based on the studies of carbon isotopes and biomarkers, only one set of effective source rock was identified in Mesozoic in the southern Ordos Basin, that is, dark shale with big thickness deposited in lacustrine environment in the Upper Triassic Yanchang Formation. The source rocks mainly distributed in Qingyang, Zhengning, Zhiluo, Wuqi, Yanchi and Huanxian County. The dark shale in the seventh member of Yanchang Formation was the most favorable source rock in the study area, providing oil and gas for not only itself but also the Fuxian, Yan'an and Zhiluo Formations of Jurassic. With weak structural fluctuation and gentle stratigraphic dip angle ( usually below 1 °) , hydrocarbon had migrated for short distance before accumulating in low-porosity and low-permeability reservoirs. Sand bodies were poorly connected and few fractures worked as vertical migration pathways. Hydrocarbon mainly accumulated in lacustrine depressions or neighboring areas. The results showed that the favorable places for prospecting in the southern Ordos Basin should be the lithologic traps close to the source rocks in Yanchang Formation.%通过碳同位素分析以及生物标志化合物对比,确定鄂尔多斯盆地南部中生界只存在一套有效烃源岩,即延长组长4+5-长8厚度较大的深灰色、灰黑色湖泊相泥页岩,其主体分布在庆阳、正宁、直罗、吴旗、盐池及环县地区的范围内,又以长7沉积期沉积的暗色泥岩为研究区最有利的烃源岩,提供了包括自身储集层以及侏罗系富县组、延安组、直罗组储集层的油气.鄂尔多斯盆地南部中生界地层平缓,陕北斜坡倾角一般小于1°,储层低孔低渗、非均质性比较严重,砂体连通性差,缺乏裂缝系统作为垂向运移通道,其油气运移的距离较短,油气主要聚集在湖相生油坳陷或邻区.因此,勘探重点应放在距离延长组烃源岩较近的岩性圈闭等.

  6. Sedimentary facies and gas accumulation model of Lower Shihezi Formation in Shenguhao area, northern Ordos basin, China

    Lin, Weibing; Chen, Lin; Lu, Yongchao; Zhao, Shuai


    The Lower Shihezi formation of lower Permian series in Shenguhao develops the highest gas abundance of upper Paleozoic in China, which has already commercially produced on a large scale. The structural location of Shenguhao belongs to the transition zone of Yimeng uplift and Yishan slope of northern Ordos basin, China. Based on the data of core, well logging and seismic, the sedimentary facies and gas accumulation model have been studied in this paper. Sedimentary facies analysis shows that the braided delta is the major facies type developed in this area during the period of Lower Shihezi formation. The braided delta can be further divided into two microfacies, distributary channel and flood plain. The distributary channel sandbody develops the characteristics of scour surface, trough cross beddings and normal grading sequences. Its seismic reflection structure is with the shape of flat top and concave bottom. Its gamma-ray logging curve is mainly in a box or bell shape. The flood plain is mainly composed of thick mudstones. Its seismic reflection structure is with the shape of parallel or sub-parallel sheet. Its gamma-ray logging curve is mainly in a linear tooth shape. On the whole, the distribution of sandbody is characterized by large thickness, wide area and good continuity. Based on the analysis of the sea level change and the restoration of the ancient landform in the period of Lower Shihezi formation, the sea level relative change and morphology of ancient landform have been considered as the main controlling factors for the development and distribution of sedimentary facies. The topography was with big topographic relief, and the sea level was relatively low in the early stage of Low Shihezi formation. The sandbody distributed chiefly along the landform depressions. The sandbody mainly developed in the pattern of multiple vertical superpositions with thick layer. In the later stage, landform gradually converted to be flat, and strata tended to be gentle

  7. Shaanxi Yanchang Petroleum (Group)Co.,Ltd


    @@ Shaanxi Yanchang Petroleum (Group)Co.,Ltd,("Yanchang Petroleum" for short), directly under the People's Government of Shaanxi Province,is now one of China's big-four oil corporations with legal exploration and production certificates. It was established in 1905 and in 1907 completed the first onshore well in China. In 1944, Chairman Mao inscribed "Working hard" to encourage it. Now it has four subordinate oil companies, such as Yanchang Oilfield Joint-stock Company, the Refining Company, the Pipeline Transportation Company and the Sales Company, and the Finance Center, as well as three subsidiaries, such as Shaanxi Xinghua Group Co., Ltd., Shaanxi Petrochemical Engineering Construction Co., Ltd. and Xi'an Yanlian Industry &Trade Co., Ltd. It subordinates several production and operation institutions, including 22 oil production plants,3 refineries and 2 marketing companies of oil products.

  8. Soft-sediment deformation structures in cores from lacustrine slurry deposits of the Late Triassic Yanchang Fm. (central China)

    Yang, Renchao; Loon, A. J. (Tom) van; Yin, Wei; Fan, Aiping; Han, Zuozhen


    The fine-grained autochthonous sedimentation in the deep part of a Late Triassic lake was frequently interrupted by gravity-induced mass flows. Some of these mass flows were so rich in water that they must have represented slurries. This can be deduced from the soft-sediment deformation structures that abound in cores from these lacustrine deposits which constitute the Yanchang Fm., which is present in the Ordos Basin (central China). The flows and the resulting SSDS were probably triggered by earthquakes, volcanic eruptions, shear stress of gravity flows, and/or the sudden release of overburden-induced excess pore-fluid pressure. The tectonically active setting, the depositional slope and the high sedimentation rate facilitated the development of soft-sediment deformations, which consist mainly of load casts and associated structures such as pseudonodules and flame structures. Sediments with such deformations were occasionally eroded by slurries and became embedded in their deposits.

  9. Ordos Takes Flight



    @@ China's vast hinterland has long conjured up images of rugged mountains and countrysides dotted by villages all but untouched by the hands of time. But after a recent one-hour flight west from Beijing,Anna Chennault,Chair of the Council for International Cooperation (CIC),a Washington,D.C.-based non-profit organization that helps promote development in China,found something altogether different-a city called Ordos.

  10. Yanchang Petroleum Group to Focus on Petrochemicals%Yanchang Petroleum Group to Focus on Petrochemicals

    Li Ying


    Century-old development Based in Northwest China's Shaanxi Province, the country's fourth largest oil producing province, and directly attached to Shaanxi People's Provincial Government, Yanchang Petroleum Group is one of the four qualified enterprises for oil and gas exploration in China, with a century-old development history. It drilled the first oil well in mainland China in 1907.

  11. Sequence framework of two different kinds of margins and their response to tectonic activity during the Middle-Late Triassic, Ordos Basin


    Two kinds of margin respectively occur in the Ordos Basin during the Middle-Late Triassic (Yanchang Age), one is foreland margin developed under the background of flexural subsidence by thrusting intensively in the southwest margin, and the other is intracratonic basin margin by stable subsidence in northern and central parts of the basin. The Middle-Late Triassic Yanchang Formation can be divided into four regional third-order sequences, which are separated by gentle angular unconformity or regional erosion surface, made up of lowstand system tract (LST), expanding system tract (EST) and highstand system tract (HST) from lower to upper within a sequence. But there are distinct differences of the sequence framework between the southwest margin and northern and central parts of the basin. The southwest margin develops heavy conglomerate layer and unconformity as a result of orogeny by thrusting, and the intracratonic basin margin by stable subsidence in the northern and central parts grows aggradational sandstone, conglomerate in fluvio-delta system and parallel unconformity. The depositional framework of southwest margin reflects the tectonic evolution from flexural subsidence by thrusting to rebounded uplift. The formation of sequence boundary is related to the resilient uplift and erosion. The sequence stratigraphic framework and depositional system tract configuration in the foreland basin are controlled by structural activity of the fold and thrust belt, and the sequence succession reflects episodic thrusting of the Middle-Late Triassic toward the foreland basin. The sequence evolution in northern and central parts reflects the depositional succession of fluvio-delta system under intracratonic background, composed of coarse-grained sediment in braided channel deposit at the lower, meandering channel deposit in the middle and fine-grained sediment in the flood plain at the upper, dominated by lake level fluctuation. During the deposit of the LST in the

  12. 鄂尔多斯盆地山西组地下咸水CO2溶解能力%CO2 Solubility in Shanxi Formation Water of Ordos Basin

    胡丽莎; 常春; 于青春


    实施CO2的地质储存是目前公认的减缓全球变暖的有效途径之一.潜在的储存场所包括衰竭的油气藏、深部不可开采煤层及深部咸水层.其中,深部咸水层储存潜力最大.在发挥作用的诸多机理中,溶解埋存具有埋存量大、作用时间较长以及安全性高的特点.在评价深部咸水含水层CO2溶解储存潜力时,溶解度是一个关键参数.提出了测定咸水含水层地层水CO2溶解度的方法,并将其实际应用于鄂尔多斯盆地山西组地层水.鄂尔多斯盆地是我国重要的能源基地,CO2排放量大,排放浓度高.采集了野外实地水样,进行了化学成分分析,并人工合成该水样;测定了40~80℃、8~12 MPa条件下CO2在该水样中的溶解度,其结果可为评价鄂尔多斯盆地深部咸水含水层埋存能力提供依据.%Geological storage is one of the most effective means to reduce the anthropogenic greenhouse gas emissions to mitigate the worsening global warming. Depleted oil-gas reservoirs, coal seams and deep saline aquifers are potential sites for CO2 geological storage of which saline aquifer has the greatest potential for sequestration. Among the many effective mechanisms, dissolving storage is characterized by large storage capacity, long action time and high safety. When evaluating the storage capacity of a deep saline aquifer, CO2 solubility becomes a key parameter. In this paper, an experimental method is proposed and used to measure the CO2 solubility in Shanxi Formation water. Ordos Basin is an important energy base for China which releases a lot of high concentration CO2. Studies show CO2 geological storage is possible in Ordos Basin since its Shanxi Formation forms many source-reservoir-cap assemblages, and it is of great importance both in theory and practice to probe into CO2 solubility in Shanxi Formation water of Ordos Basin. In this paper, chemical composition of Shanxi Formation water collected from the Ordos Basin

  13. Sequence Stratigraphy and Sedimentary Facies in the Lower Member of the Permian Shanxi Formation, Northeastern Ordos Basin, China

    Wei Du; Zaixing Jiang; Ying Zhang; Jie Xu


    The Lower Permian Shanxi(山西) Formation is one of the main gas-bearing stratigraphic units in northeastern Ordos(鄂尔多斯) Basin,China.Based on an integrated investigation of well logs,cores,and outcrop,we delineated the sedimentary facies of the lower member of the Shanxi Formation and divided the succession into three third-order sequences from base to top as SQ1,SQ2,and SQ3.The lower region of Shanxi Formation was deposited in the following sedimentary facies or subfacies: subaqueous braided channel,subaqueous interdistributary,mouth bar,swamp and shelf in the Daniudi(大牛地)Gas Field and braided channel,and shelf and lake at Heidaigou(黑岱沟)outcrop.Braided-river deposits form the lowstand systems tract (LST) in each sequence.Braided channels mark the sequence boundaries at Heidaigou outcrop.A shelf and lake depositional environment with dark gray mudstone forms the transgressive systems tract (TST).The location where dark gray mudstone first appears above the braided channel marks the first flooding surface (FFS),and the end of that marks the maximum flooding surface (MFS).The highstand systems tract (HST) deposits are fine-grained sediments with an aggradational parasequence at Heidaigou outcrop and swamp coalbed in the Daniudi Gas Field.Mouth-bar sand bodies in braided delta front,which form the LST in each sequence,form excellent reservoirs in the Daniudi Gas Field.


    张金良; 郭爱华; 李浩; 张慧元


    In recent years,along with the exploration change of Yanchang formation in strategy, Pingbei exploration area achieved new discovery in Chang 8 and Chang 9 oil group of Yanchang formation. Based on the massive core data,with SEM observations microscopic-analysis, casting thin sections and conventional Hg injection techniques, the results showed Chang 9 oil group is shallow lake deposition and sediments are fine. Chang 8 oil group locates in Ansai delta front, underwater distributary channel and debouch bar sandbodies whose storage space are big developed. Reservoir space is made up of original residual pore between grains. There is one set of premium hydrocarbon source rock on the top of Chang 9 oil group,about 5~14 m thick,which generate hydrocarbons strongly. There are three types of reservoir assemblage in this area, self-generation and self-accumulation ones, lowe generation and high accumulation ones, high generation and low accumulation ones. According to oil-test results of Chang 8 and Chang 9 oil group, self-generation and self-accumulation ones, low generation and high accumulation ones in Pingbei exploration area present good oil exploration prospect. Oil-bearing area can be increased by progressive exploration,it's also the replacement resources of next exploitation.%以大量的岩心和测井资料为基础,利用铸体薄片、扫描电镜及压汞等测试分析方法,对坪北探区延长组长8和长9油层组的沉积环境、储层特征以及生储盖的组合关系进行了研究,结果表明长9期属浅湖相沉积,沉积物普遍较细,其顶部发育一套优质烃源岩,厚度5~14 m,具有良好的供烃能力;长8期位于安塞三角洲沉积前缘,主要发育三角洲前缘水下分流河道和河口坝砂体,具有良好的储集空间,以原生残余粒间孔隙为主;区域内发育自生自储式、下生上储式、上生下储式3种成藏组合类型.根据坪北探区延长组长8、长9层试油成果,综合评价认为

  15. Late Triassic tuff intervals in the Ordos basin, Central China: Their depositional, petrographic, geochemical characteristics and regional implications

    Qiu, Xinwei; Liu, Chiyang; Mao, Guangzhou; Deng, Yu; Wang, Feifei; Wang, Jianqiang


    Tuff intervals of Upper Triassic Yanchang Formation are laterally widespread in the Ordos basin, Central China. This paper focuses on magmatic origins and potential source regions of these tuff intervals through detail depositional, petrographic and geochemical analyses. Most of the tuff intervals are well-documented at the bottom of the Chang7 oil reservoir unit and can be correlated laterally, and certain tuff beds are reworked by turbidity current or seismic activity. Petrographic studies of the Chang7 tuffs indicate that they are composed of crystal shards, lithic shards and altered glass shards, and the crystal shards include plagioclase, quartz and biotite. Alteration of the Chang7 tuffs is ubiquitous, thus, most of these tuffs transformed into illite/smectite (I/S) mixed-layers which are identified by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Less common minerals are also detected in the Chang7 tuffs such as zircon, hematite, siderite, anatase. Major elements are determined by the X-ray fluorescence (XRF) analysis, the results indicate that the Chang7 tuffs are enriched in K2O (average 4.21%), the ratio of SiO2/Al2O3 ranges from 1.73 to 2.85 (average 2.17), and the ratio of TiO2/Al2O3 varies between 0.006 and 0.032 (average 0.017), which imply that the Chang7 tuffs originated from a felsic parental magma. Trace elements are determined by inductively coupled plasma mass spectrometry (ICP-MS), indicating the total rare earth element (∑REE) concentrations are variable, and range from 117.46 to 466.83 ppm (average 251.88 ppm). REE distribution pattern of the Chang7 tuffs presents a LREE rightward incline with flat HREE curve. The value of δEu ranges from 0.151 to 0.837 (average 0.492), suggesting a strong to weak negative Eu anomaly. The Chang7 tuffs show positive anomalies in Rb, Th and U and negative anomalies in Nb, Sr and Eu on a primitive mantle normalized spidergram. A preliminary analysis of the geochemical composition of the

  16. Determination of paleo-pressure for a natural gas pool formation based on PVT characteristics of fluid inclusions in reservoir rocks--A case study of Upper-Paleozoic deep basin gas trap of the Ordos Basin

    MI Jingkui; XIAO Xianming; LIU Dehan; SHEN Jiagui


    It has been proved to be a difficult problem to determine directly trapping pressure of fluid inclusions. Recently, PVT simulation softwares have been applied to simulating the trapping pressure of petroleum inclusions in reservoir rocks, but the reported methods have many limitations in practice. In this paper, a method is suggested to calculating the trapping pressure and temperature of fluid inclusions by combining the isochore equations of a gas-bearing aqueous inclusion with its coeval petroleum inclusions. A case study was conducted by this method for fluid inclusions occurring in the Upper-Paleozoic Shanxi Formation reservoir sandstones from the Ordos Basin. The results show that the trapping pressure of these inclusions ranges from 21 to 32 MPa, which is 6-7 MPa higher than their minimum trapping pressure although the trapping temperature is only 2-3℃ higher than the homogenization temperature. The trapping pressure and temperature of the fluid inclusions decrease from southern area to northern area of the basin.The trapping pressure is obviously lower than the state water pressures when the inclusions formed. These data are consistent with the regional geological and geochemical conditions of the basin when the deep basin gas trap formed.

  17. 鄂尔多斯盆地马五5亚段沉积微相分布及演化%Distribution and evolution of sedimentary microfacies of submember 5 Majiagou Formation in the Ordos basin

    包洪平; 张云峰; 王前平; 董兆雄; 武春英; 杨西燕


    The difference between lithology and depositional environment is the main cause of reservoir heteroge-neity in submember 5 Majiagou Formation of Lower Ordovician in the Ordos basin. According rock types, sedi-mentary structures, color and its relationship with sedimentary environment, two subfacies and seven microfacies in submember 5 Majiagou Formation are classified. subfacies include basin-marginal tidal flat and intra-platform basin. The former can be furtherly divided into four types microfacies, such as intra-platform margin (gypsum) dolomite depression, intra-platform margin dolomite tidal flat, intra-platform margin calcitic tidal flat and in-tra-platform margin dolomite calcitic–calcitic dolomite tidal flat. The latter can be furtherly divided into three types microfacies, such as basin (gypsum) dolomite depression, dolomite calcitic–calcitic dolomite basin and calcitic ba-sin. In the stage of submember 5-1 Majiagou Formation, Ordos basin basement uplift, the ancient land expand, re-duce sea level, shallow sea, the ancient central uplift belt out of the water are the performance of sedimentary mi-crofacies plane. North area is mainly developing intra-platform margin dolomite tidal flat-dolomite depression, in-tra-platform margin dolomite calcitic-calcitic dolomite tidal flat and calcitic basin. West area develop in-tra-platform margin dolomite tidal flat-dolomite depression, intra-platform margin dolomite calcitic-calcitic dolo-mite tidal flat. Center area develop calcitic basin, and mix dolomite calcitic basin and basin dolomite depression. In the stage of submember 5-2 Majiagou Formation, north area mainly developing intra-platform margin dolomite tidal flat and dolomite depression. Secondary microfacies include dolomite calcitic–calcitic dolomite tidal flat, cal- citic tidal flat. In western area, the main microfacies include intra-platform margin dolomite tidal flat and dolomite depression. In center area, the main microfacies include calcitic

  18. 鄂尔多斯盆地米兰科维奇旋回在延长组发育的一致性%Uniformity of the Milankovitch Cycle developed in the Yanchang Formation in east Gansu with the Milankovitch Cycle developed in other areas in Ordos Basin

    李凤杰; 郑荣才; 赵俊兴



  19. 鄂尔多斯盆地上三叠统延长组长4+5油层组中的古地震记录%Paleo-seismic records of Chang 4+5 oil-bearing intervals of the Upper Triassic Yanchang Formation in Ordos Basin

    邵晓岩; 田景春; 张锦泉; 赵先超; 韩永林; 王海红



  20. Quantitative simulation of porosity-evolution in the Member 8 sandstone reservoir of the Yanchang formation in Huanxian Oilfield, Ordos Basin%鄂尔多斯盆地环县地区长8段砂岩储层孔隙度演化定量模拟


    Thin section analysis indicated that the diagenesis of the sandstone reservoir in the research area had mainly undergone the processes of compaction, cementation and dissolution. Combined with the mathe-matical statistics method, the methodology was based on an analysis of tight sandstone reservoir characteristics, controlling factors and a study of the burial history and diagenetic history of the study area. With current porosity as boundary constraint conditions, the geological time and burial depth as variables, the whole porosity evolution from initial burial until the present was divided into two independent processes: porosity decrease and porosity increase, for which two mathematical models were established respectively. The quantitative simulation result indicates that the whole porosity-evolution quantitative simulation was a piecewise function with four sections. That is, the porosity decrease model for the mechanical compaction and cementation stages served a continuous exponential function with the geological time and burial depth as the variables, and the secondary porosity increase was caused by organic acid dissolution within a temperature window of 80∼100◦C. Therefore, the dissolution phase was of a porosity increase model, which was a composite function of the depth, burial time and porosity decrease amount. After the dissolution phase, the porosity was in the phase of compaction and maintenance. Finally, through the exemplification, it was verified that the porosity-evolution quantitative simulation established by the present researcher is consistent with actual geological conditions and can be applied to porosity calculation of any stratum in the study area.%  在充分分析研究区长8段砂岩储层特征、主控因素及地层埋藏史和成岩史的基础上,应用数理统计方法,以现今孔隙度为约束条件,将孔隙度演化分为减小和增大两个过程,分别建立了鄂尔多斯盆地环县地区长8段砂岩储层从埋藏初始至现今的孔隙度随埋藏深度和地史时间变化的演化模型。结果表明孔隙度定量演化模型为一个4段式分段函数。机械压实和胶结阶段为孔隙度减小模型,是对埋深和埋藏时间的指数函数。次生增孔是由于地层酸性流体的溶蚀作用而产生的,主要发生在80∼100◦C的温度窗口内。因此,溶蚀阶段为孔隙度增大模型,是对埋深、埋藏时间及增孔过程的复合函数。溶蚀阶段结束后地层孔隙度为压实和保持阶段。最后进行实例验证,验证结果表明该方法建立的砂岩孔隙度定量演化模型符合地质实际,具有较好的应用效果。


    时保宏; 张艳; 张雷; 杨亚娟


    利用岩心、测井等资料对鄂尔多斯盆地长7浊积岩特征及成藏条件的分析结果表明,长7油层组沉积层理、沉积构造及砂岩粒度等反映晚三叠世延长组长7沉积时在深湖—半深湖相发育浊积岩.长7浊积岩的电性响应特征表现为自然伽马曲线具有明显的齿化现象,在地震反射剖面上则表现为不稳定沉积、相带变化大等特点.浊积岩储集体的物性条件相对较差,孔隙度平均为8.5%,渗透率平均为0.12×10-3μm2,属超低孔、低渗储层,但由于其紧邻优质烃源岩,成藏条件优越,可大面积成藏.%With the help of the data of cores and well loggings, the characteristics of the turbidite and the conditions of the reservoir formation are analyzed for the above group of Ordos Basin. The analyzed results show that the sedimentary beddings, structures, sandstone particles and so on of the reservoir group reflect the deep and semi-deep lake facies developed environments of Late Triassic Yanchang Formation. The response characteristics of electrical property of Chang 7 Group turbidite display the obvious toothed phenomenon of GR ( gamma ray) curve, and moreover show the features of the unstable sedimentation and enormous facies changes on the seismic reflection profiles. The physical conditions of the turbidite accumulating body are relatively poorer, whose average porosity and permeability are respectively 8. 5% and 0. 12 × 10-3μm2 , belong to ultra-low porosity and low permeability reservoir. However, for the body is close to the regions with high-quality source rocks and favorable hydrocarbon enriched conditions, so it can form reservoirs on a large scale.

  2. 鄂尔多斯盆地苏里格地区奥陶系马家沟组白云石化%Dolomitization of Ordovician Majiagou Formation in Sulige region, Ordos Basin

    付金华; 王宝清; 孙六一; 包洪平; 徐波


    The Ordovician Majiagou Formation in Sulige region of the Ordos Basin was deposited in hypersaline restricted epicontinental environment. It is mainly composed of carbonate rocks with thin evaporate interbeds. The dolomites are classified into 3 kinds; micrite, fine-medium crystal dolomite, and dolomite filled in pores and fractures. The Na concentrations range from 0 to 2 099 X 10-6, the Sr concentrations range from 0 to 70 X 10-6,the Mn concentrations range from 0 to 112 X 10-6, and the Fe concentrations range from 39 to 86 746 X 10-6 in dolomites. The dolomites are characterized with varied Na, low Sr and Mn, and high Fe concentrations. The 18O values for dolomites range from -16. 00%0 to -5. 73%o, and the 13C values range from -11. 46%0 to 1. 90%. (PDB). It indicates that carbonate rocks have experienced leaching and burial diagenesis. Most filled dolomites have lower 18O and 13C values than surrounding components, indicating that the former was formed later. The dolomites are characterized with low degrees of order and less stoichiometry. The 87Sr/86 Sr values of dolomites range from 0. 707 977±0. 000 070 to 0. 711 791±0. 000 064, most of which are higher than that corresponding to global boundary between middle and upper Ordovician. Microbial dolomitization is the reason for dolomite genesis.%苏里格地区马家沟组为一套碳酸盐岩为主,夹蒸发岩的地层,沉积于超盐度的局限陆表海环境.白云石分为以泥晶结构为主的,以细—中晶结构为主和充填于孔、缝中3类.白云石Na含量(0~2 099)×10-6,Sr含量(0~70)×10-5,Mn含量(0~112)×10-6,Fe含量(39~86 746)×10-6,以变化较大的Na含量、低的Sr和Mn含量,高的Fe含量为特征.白云石δ18()值在-16.00‰~-5.73‰之间,δ13C值在-11.46‰~1.90‰之间,说明碳酸盐岩经历了淋滤作用和埋藏作用.大多数孔、缝充填白云石较围岩组分有较低的δ18O和δ13C值,说明孔缝充填的白云石形成较晚.白云石以低

  3. Evolution of the Ordos Plateau and environmental effects


    Based on the analysis of temporary-spatial distribution, geomorphic position, contact relationship with underlying strata and grain size of red clay, we studied the formation and environmental background of red clay. During late Miocene-Pliocene, the Ordos Block finished the transformation from the basin to the plateau, which had an obvious environmental effect on the topography, indicated by the formation of highland undergoing wind erosion and lowland receiving red clay deposits. The red clay materials were sourced from dusts carried by wind energy and covered on the initial topography. Unlike Quaternary loess dust covering the overall the Loess Plateau, red clay deposited on the highland would be transported to the lowlands by wind and fluvial process. As a result, there was no continuous "Red Clay Plateau" in the Ordos region and red clay was only preserved in former lowlands. However, red clay was discontinuously distributed through the Loess Plateau and to some extent modified the initial topography. The differential uplift in interior plateau is indicated by the uplift of northern Baiyushan, central Ziwuling and southern Weibeibeishan. The Weibeibeishan Depression formed earlier and became the sedimentary center of red clay resulting in the thicker red clay deposits in Chaona, Lingtai and Xunyi. Since Quaternary the aridity in the northern plateau enhanced and accelerated loess accumulation caused the formation of the Loess Plateau. During the late Pleistocene the rapid uplift led to the enhancement of erosion. Especially after the cut-through of Sanme Lake by the Yellow River, the decline of base level caused the falling of ground water level and at the same time the increase of drainage density resulting in the enhancement of evaporation capacity, which enhanced the aridity tendency of aridity in the Loess Plateau region.

  4. A feasibility study of geological CO2 sequestration in the Ordos Basin, China

    Jiao, Z.; Surdam, R.C.; Zhou, L.; Stauffer, P.H.; Luo, T.


    The Shaanxi Province/Wyoming CCS Partnership (supported by DOE NETL) aims to store commercial quantities of CO2 safely and permanently in the Ordovician Majiagou Formation in the northern Ordos Basin, Shaanxi Province, China. This objective is imperative because at present, six coal-to-liquid facilities in Shaanxi Province are capturing and venting significant quantities of CO2. The Wyoming State Geological Survey and the Shaanxi Provincial Institute of Energy Resource and Chemical Engineering conducted a feasibility study to determine the potential for geological CO2 sequestration in the northern Ordos Basin near Yulin. The Shaanbei Slope of the Ordos Basin is a huge monoclinal structure with a high-priority sequestration reservoir (Majiagou Formation) that lies beneath a 2,000+ meter-thick sequence of Mesozoic rocks containing a multitude of lowpermeability lithologies. The targeted Ordovician Majiagou Formation in the location of interest is more than 700 meters thick. The carbonate reservoir is located at depths where pressures and temperatures are well above the supercritical point of CO2. The targeted reservoir contains high-salinity brines (20,000-50,000 ppm) that have little or no economic value. The targeted reservoir is continuous as inferred from well logs, and cores show that porosity ranges from 1 to 15% with average measured porosity of 8%, and that permeability ranges from 1-35 md. This paper focuses on calculations that will help evaluate the capacity estimates through the use of high-resolution multiphase numerical simulation models, as well as a more simple volumetric approach. The preliminary simulation results show that the Ordovician Majiagou Formation in the Ordos Basin has excellent potential for geological CO2 sequestration and could store the CO2 currently emitted by coal-to-liquid facilities in Shaanxi Province for hundreds of years (i.e., 9 Mt/year CO2; 450 Mt over a 50-year period at one injection site). ?? 2011 Published by Elsevier Ltd.

  5. Upper Paleozoic petroleum system, Ordos Basin, China

    Xiao, X.M.; Zhao, B.Q.; Thu, Z.L.; Song, Z.G. [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wilkins, R.W.T. [CSIRO Petroleum, P.O. Box 136, North Ryde, NSW 2113 (Australia)


    The Ordos Basin is a typical lapped basin, including three sequences of strata: early Paleozoic, late Paleozoic and Mesozoic, with a total thickness of 4000-6000m. Impermeable sealing beds are well developed at the top and base of the upper Paleozoic sequence, separating it from the Mesozoic and the lower Paleozoic strata to form an independent petroleum system. In this petroleum system, the source rocks are widely distributed coals and dark mudstones occurring in the Carboniferous-lower Permian coal measures, with a thickness of 10-15 and 40-60m, respectively. The reservoirs are mainly early Permian tight sandstones, mostly with a porosity of 4-8% and a permeability of 0.1-1.0x10{sup -3}{mu}m{sup 2}. The regional cap rock is a 100-150m thick mudstone in the upper Permian strata. The structural framework of the basin is a huge asymmetric syncline, dipping gently toward the east and north, and steeply toward the south and west. Well data show that gas-saturated, gas-water transition and water-saturated zones are developed from the depositional center to the basin edges. The gas-saturated zone mainly lies in the gently dipping slope area of the Shanbei Slope. Toward eastern and northern up-dip directions the water-gas transitional zone occurs, and finally the water-saturated zone, presenting a reverse relation of water on top of gas. An abnormal negative strata pressure is developed in the gas-bearing area, with a pressure coefficient (C{sub p}) ranging from 0.83 to 0.95. Fluid inclusion data indicate that the upper Paleozoic gas pool began to develop around the Wuqi area at about 150Ma, and it extended toward the north and was largely formed at about 120Ma, showing there was a regional migration of the gas-water interface from south to north during the gas pool formation. These characteristics appear to show that the northern and eastern margins of the petroleum system are defined by a regional hydrodynamic regime. The critical moment of the petroleum system

  6. Basement faults and volcanic rock distributions in the Ordos Basin


    Volcanic rocks in the Ordos Basin are of mainly two types: one in the basin and the other along the margin of the basin. Besides those along the margin, the marginal volcanic rocks also include the volcanic rocks in the Yinshanian orogenic belt north of the basin. Based on the latest collection of gravitational and aeromagnetic data, here we interpret basement faults in the Ordos Basin and its peripheral region, compare the faults derived from aeromagnetic data with those from seismic data, and identify the geological ages of the fault development. Two aeromagnetic anomaly zones exist in the NE-trending faults of the southern basin, and they are in the volcanic basement formed in pre-Paleozoic. These NE-trending faults are the channel of volcanic material upwelling in the early age (Archean-Neoproterozoic), where igneous rocks and sedimentary rocks stack successively on both sides of the continental nucleus. In the Cambrian, the basin interior is relatively stable, but in the Late Paleozoic and Mesozoic, the basin margin underwent a number of volcanic activities, accompanied by the formation of nearly north-south and east-west basement faults in the basin periphery and resulting in accumulation of great amount of volcanic materials. Volcanic tuff from the basin periphery is discovered in the central basin and volcanic materials are exposed in the margins of the basin. According to the source-reservoir-cap rock configuration, the basin peripheral igneous traps formed in the Indosinian-Early Yanshanian and Late Hercynian are favorable exploration objectives, and the volcanic rocks in the central basin are the future target of exploration.

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

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


    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.

  8. 鄂尔多斯盆地山西组沉积环境讨论及其地质启示%Discussion of sedimentary environment and its geological enlightenment of Shanxi Formation in Ordos Basin

    陈洪德; 李洁; 张成弓; 程立雪; 程礼军


    Late Paleozoic of Ordos Basin has undergone a huge change of the level, and occurred many times the transgression which, on the Benxi-Taiyuan background of epicontinental deposition by long-term studies have reached a broad consensus, while the conversion of a critical period in the sea deposition of Shanxi has a rather controversy. In view of the actual, this article was known as the starting point of previous achievement According to the distribution of marine strata, paleontology, sedimentary structures, petrography, diagenesis and other geological basis for the reference, comprehensive calculation of boron law paleosalinity, Sr/Ba ratio and boron gallium rubidium content of the relationship between the three elements of different geochemical test results, mainly for the Early Permian Shanxi Period which is the conversions of marine-continental facies sedimentary environment for a more in-depth analysis. That Shanxi 2 is still in the context of epicontinental marine sedimentation stage Shanxi 1 is the conversions of marine-continental stage as a critical period of transition, and Xiashihezi Period before they are fully into the new evolution of continental basins stage. Establishing the geochemical proxies section of east-west and north-south in Ordos Basin. Summed up the ancient salinity and Sr/Ba ratio from south to north, from west to east, there is the general trend of decreasing. And such trends in the early and mid-Shanxi 2 were most clearly, as the latter regression continues to expand, disappeared late in the Shanxi 1. The reason can be attributed to the ancient geography of the period and what impact the two sea water level differences. On this basis, the Ordos Basin Late Paleozoic sedimentary evolution is divided into three stages, and it is base on super long-term base level cycle eventually to the establishment of the sequence stratigraphic framework.%鄂尔多斯盆地晚古生代经历了巨大的海陆变迁,并发生多次海侵.其中,关于

  9. Middle Ordovician Bioturbation Structures from Southeastern Margin of Ordos Basin and Their Environmentary Interpretation


    Trace fossils were discovered in the Middle Ordovician Badou Member of Fengfeng Formation and the Member 1 of Jinsushan Formation in Mt. Jinsu of the Fuping region which lies at the southeastern margin of the Ordos basin. The rocks of the fore-mentioned parts contain a considerable amount of bioturbation structures, in which ichnogenus and ichnospecies can not be identified, and abundant stromatolites.The distributions and characteristics of the bioturbation structures are analyzed and summarized in this paper. The paleoenvironments of related formations and members were interpreted in the method of semiquantitative analysis of bioturbation structures with researches on stromatolites and sedimentology. It is suggested that Fuping zone, located in the southeastern margin of the Ordos basin, was a carbonate platform where stromatolite-developing tidal flat and low-energy subtidal open platform environments dominated. Also that this zone experienced three paleogeographic evolutions from tidal flat to low-energy subtidal open platform environments, that is, three larger-scale eustatisms occurred during the sedimentary period of Middle Ordovician Badou Member of Fengfeng Formation to the Member 1 of Jinsushan Formation.

  10. 鄂尔多斯盆地吴旗油区早侏罗世古地貌特征与油气富集关系%Palaeogeomorphological features and their bearings on the hydrocarbon accumulation in the Wuqi oil field, Ordos Basin during the Lower Jurassic

    于雷; 施泽进; 李恕军; 陈建文; 田亚铭


    沉积时期的古地形、古地貌是控制沉积相发育与分布的一个重要因素,其在一定程度上也控制着后期油气圈闭的类型与分布。通过补偿印模法恢复了吴旗油区前侏罗纪古地貌形态,确定局部构造特征,开展有利储集相带预测。研究区油藏分布主要受控于古地貌形态,深切延长组的古河谷是油气运移的主要通道,古地形高部位为油气运移的主要方向,古河谷附近的砂体为油气富集的有利场所,上覆的沼泽相泥岩形成了良好的岩性遮挡条件。%The palaeogeomorphological features during the depositional periods are interpreted as important factors to control the development and distribution of sedimentary facies,and to a certain extent,to control the types and distribution of oil traps in the Wuqi oil field,Ordos Basin. In this study,the compensation impression method is employed to reconstruct the pre-Jurassic palaeogeomorphological features,clarify the local structural features,and predict the favourable reservoir facies zones. The palaeogeomorphological features controlling the distribution of oil pools in the study area include the palaeovalleys incised into the Yanchang Formation as main channels for the migration of hydrocarbons;topographic highs as the main direction for the migration of hydrocarbons;the sandstones along the palaeovalleys as the favourable localitites for the accumulation of hydrocarbons,and the overlying marsh mudstones as good lithologic barrier.

  11. Groundwater Systems and Resources in the Ordos Basin, China

    HOU Guangcai; LIANG Yongping; SU Xiaosi; ZHAO Zhenghong; TAO Zhengping; YIN Lihe; YANG Yuncheng; WANG Xiaoyong


    The Ordos Basin is.a large-scalesedimentary basin in northwestern China. The hydrostratigraphic units from bottom to top are pre-Cambrian metamorphic rocks, Lower Paleozoic carbonate rocks, Upper Paleozoic to Mesozoic clastic rocks and Cenozoic deposits. The total thickness is up to 6000 m. Three groundwater systems are present in the Ordos Basin, based on the geological settings, I.e. The karst groundwater system, the Cretaceous dastic groundwater system and the Quaternary groundwater system. This paper describes systematically the groundwater flow patterns of each system and overall assessment of groundwater resources.

  12. Geochemical behaviors and genesis of formation water in 8 th Member of Xiashihezi Formation in western Sulige gas field,Ordos Basin%鄂尔多斯盆地苏里格气田西部盒8段地层水地球化学特征及成因

    梁积伟; 李荣西; 陈玉良


    Genesis of formation water of 8th Member of Xiashihezi Formation (H8) and their relationships with gas accu-mulation in western Sulige gas field of Ordos Basin in central China was studied by means of analysis of the geochemical behaviors of formation water samples from 39 gas wells .The distribution regularity of oil ,gas and water was investigated . There is an obvious difference in the concentration ( r) of anion and cation of formation water .Content of Cl -is very high and dominant among the anions of the water ,while that of HCO 3-and SO 2-4 are very low .Content of Ca 2+is the highest among the cations of formation water ,followed by K ++Na +,while the content of Mg 2+is low.The formation water show property of weak acidity with medium-high salinity .The calcium chloride Ⅴ-type water is predominant ,with the calcium chloride Ⅲ-type and Ⅳ-type water occurring locally .The chemical characteristic parameters of the formation water are characterized by low sodium-chloride ratio (rNa +/rCl-),high coefficient of desulfurization (2 ×100 ×rSO2-4 /rCl-),high metamorphic coefficient[ 12 (rCl--rNa +)/rMg2+]and low magnesium-chloride ratio ( rMg2+/rCa2+).The formation water of H8 in western Sulige gas field has the characteristics of gas-associated water .It could be residual formation water formed when gas was charged under a closed and reducing environment .The distribution of formation water is controlled by sand body and reservoir conditions .Three genetic types of formation water are identified , namely the closed formation water within isolated sand body ,the residual water with weak dynamic and incomplete gas-water displacement ,and the stagnant water at lower position of large sand body .%通过对苏里格气田西部盒8段地层水性质及地球化学特征研究,推断地层水的成因,寻找天然气富集区,揭示气田油、气、水分布规律。苏里格气田西部39口井的地层水具有如下地球化学特征:①地

  13. Attenuation of S wave in the crust of Ordos massif

    LIU Hong-gui; CHUO Yong-qing; CHEN Shu-qing; JIN Chun-hua


    We presented attenuation characteristics of S waves in the crust of Ordos massif. Using 487 pieces of digital oscillograms of 19 seismic events recorded by 32 seismologic stations located on Ordos massif and its surroundings, we have calculated the parameter of three-segment geometric attenuation and give the relation of inelastic attenuation Q value with frequency in the crust of Ordos massif, site responses of 32 stations, and source parameters of 19 events by the genetic algorithm. The results indicate that Q value (at 1 Hz) of S-wave in the crust of Ordos massif is much larger than that in the geologically active tectonic region. The site responses of the 32 stations in the high-frequency section do not show clear amplification effect except one or two stations, while in the low-frequency section, there is difference among the stations. The logarithmic value of seismic moment and the magnitude ML of 19 seismic events has a very good linear relationship.

  14. Electrical Structure of the Crus Beneath the Ordos Block

    Zhao Guoze; Zhan Yan; Wang Lifeng; Wang Jijun; Tang Ji; Chen Xiaobin; Xiao Qibin


    The Ordos block is a stable tectonic unit since the Cenozoic. Whether low-resistivity layers exist in the middle and lower crust of this kind block is an open question. This work attempts to reveal the entire crustal structure of the block based on interp

  15. Hydrochemical characterization and pollution sources identification of groundwater in Salawusu aquifer system of Ordos Basin, China.

    Yang, Qingchun; Wang, Luchen; Ma, Hongyun; Yu, Kun; Martín, Jordi Delgado


    Ordos Basin is located in an arid and semi-arid region of northwestern China, which is the most important energy source bases in China. Salawusu Formation (Q3 s) is one of the most important aquifer systems of Ordos Basin, which is adjacent to Jurassic coalfield areas. A large-scale exploitation of Jurassic coal resources over ten years results in series of influences to the coal minerals, such as exposed to the oxidation process and dissolution into the groundwater due to the precipitation infiltration. Therefore, how these processes impact groundwater quality is of great concerns. In this paper, the descriptive statistical method, Piper trilinear diagram, ratios of major ions and canonical correspondence analysis are employed to investigate the hydrochemical evolution, determine the possible sources of pollution processes, and assess the controls on groundwater compositions using the monitored data in 2004 and 2014 (before and after large-scale coal mining). Results showed that long-term exploration of coal resources do not result in serious groundwater pollution. The hydrochemical types changed from HCO3(-)-CO3(2-) facies to SO4(2-)-Cl facies during 10 years. Groundwater hardness, nitrate and sulfate pollution were identified in 2014, which was most likely caused by agricultural activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Research on CO2 Quality Pipeline Transportation Based on Yanchang Oilfield CCUS

    Yang Yongchao


    Full Text Available CO2 capture,utilization and storage (CCUS is now recognized as an important technology in the global scope of CO2 emission reduction, pipeline transportation is the main center to connect the capture point and the use storage point, the first issue to CO2 pipeline transportation is to solve CO2 source quality research. Yanchang Oilfield has the advantages of CCUS, its coal chemical capture of CO2 contains different impurities. In the CO2 pipeline transportation, the impurity content in CO2 is based on its end use and the actual situation of pipeline. The impurities will affect the efficiency of CO2-EOR, the choice of CO2 state equation, the changes of CO2 phase diagram and the capacity of pipeline transportation.

  17. 鄂尔多斯盆地陇东地区延长组砂岩成岩作用及孔隙演化%Diagenesis and porosity evolution of sandstones in Longdong Area, Ordos Basin

    钟大康; 祝海华; 孙海涛; 蔡超; 姚泾利; 刘显阳; 邓秀芹; 罗安湘


    Researches based on the pore casting thin sections, scanning electron microscopy (SEM) and X-ray diffraction, combined with the analysis of physical properties, have shown that the types of the sandstone reservoirs of Triassic Yanchang Formation in Longdong Area, Ordos Basin, are lithic arkose sandstone, feldspathic lithic sandstone and arkose with low compositional and low structural maturities. The high quality reservoirs were mainly developed in some coarse grained sandstones rich in rigid grains. The primitive porosity of this sandstone is approximately 39% from some empirical formula. During burring, its porosity decreased to 18. 5% due to the fast burial and richness in the shale, slate and phyllite debris. Afterwards, the porosity continually decreased in some extent (3. 5%) as a result of the overgrowth of quartz and chlorite cementation. Constantly, the calcite and dolomite cementation contributed a porosity loss of about 5%. Afterwards, the dissolutions of carbonate cement, feldspar and debris made a contribution to the increase of porosity by about 4%-8%. Finally, the dissolution pores and some primary pores were infilled by ferrocalcite and ankerite cement.%大量岩石薄片、孔隙铸体薄片、扫描电镜与X衍 射以及常规物性等分析资料研究表明,鄂尔多斯盆地陇东地区三叠系延长组砂岩主要为成分成熟度及结构成熟度较低的长石质岩屑砂岩、岩屑砂岩和长石砂岩.优质储层主要发育于粗粒富含刚性颗粒的砂岩中,这类砂岩在埋藏过程中由于早期快速埋藏加之泥岩、板岩及千枚岩岩屑含量高,经历了强烈的压实作用,使其由原始孔隙度大约为39%降低至18.5%;此后发生石英颗粒次生加大及绿泥石胶结,使孔隙有一定程度的损失(大约3.5%);紧随其后的是方解石及白云石碳酸盐胶结,损失孔隙度5%;后来出现碳酸盐胶结物与长石及岩屑的溶蚀作用,新增加孔隙度4%~8%,

  18. Application of Fluid Inclusions in the Study of Natural Gas Geology in Ordos Basin

    FAN Ai-ping; YANG Ren-chao; FENG Qiao; LIU Yi-qun; HAN Zuo-zhen


    The new recently demonstrated reserves of oil and gas in the Ordos basin are found at the top of petroliferous basins in China. Gas pools discovered in recent years in the Permian system have become the main natural gas resource in the basin. Therefore, synthetic research on fluid inclusions should be done in order to ascertain the pool-forming stage, the maturity of organic matters and the properties of Paleo-fluids. The main types of fluid inclusions in the Permian system in the basin include brine inclusions, carbon dioxide inclusions and organic inclusions. Homogenization temperatures (HT) of brine inclusions can be divided into four intervals: 66-83 ℃, 86-108 ℃, 112-138 ℃ and 142-153 ℃. The fluid inclusions in the interval of 112-138 ℃ are much more than that of other intervals, indicating that the second stage of hydrocarbon migration associated with the third temperature interval is the most important stage of gas pool formations. The fluid inclusion has extensive applications in the study of gas geology, not only in ascertaining the formation stage of gas pools, but also in estimating the maturity of organic matter and restoring Paleo-fluids. The result of testing the HT of brine inclusions shows that there are two stages of gas pool formations in the Permian system occurring ±150 Ma and ±100 Ma. The maturity of organic matter is moderate to high, a conclusion based on the color of fluid inclusions (radiated by fluorescence). The high salinity of Paleo-fluids of the NaCl-H2O and CaCl2-H2O systems shows good preservation conditions of the Paleo-fluids. Two stages of reservoir filling, high maturity of organic matter and good preservation conditions are factors favorable for the formation and preservation of large-scale gas pools in the Permian system in the Ordos basin.

  19. 鄂尔多斯盆地下奥陶统马家沟组障壁潟湖沉积相模式及有利储层分布规律%Barrier- Lagoon Sedimentary Model and Reservoir Distribution Regularity of Lower-Ordovician Majiagou Formation in Ordos Basin

    周进高; 张帆; 郭庆新; 邓红婴; 辛勇光


    Lower Ordovician Majiagou Formation is composed of six members in which Ma1, Ma3 and Ma5 are evaporate including dolomite, anhydrite and salt and Ma2, Ma4, Ma6 are limestone with dolomite in Ordos Basin. Majiagou Formation is formed by cyclic sedimentation by intermeshed evaporite and carbonate. Upwarps around the basin and a downwarp in the centre of the basin constitute the Early-Ordovician Palaeogeomorphologic pattern. Upwarps as underwater barriers led to exchange limitation between lagoon and exterior sea and weakness of lagoon hydrodynamic force during high sea level stage. During low sea level stage, upwarps resulted in the entire isolation between lagoon and exterior sea. Owing to the strong evaporation, lagoon level was greatly lower than exterior sea level . So lagoon margin flat was partly exposed to atmosphere and the deep sag in the centre of the basin was covered by concentrated bittern.Analysis of single well and well tie sedimentary facies demonstrates the depositional setting from Ma1 and Ma2 member is composed of two integrating cycles from transgression to regression due to sea water invasion from the east and southeast of the basin. Ma3 member is mainly composed of regressive deposition owing to the rapid extensive transgression in the early Ma3 stage. North China sea, Qilian oceanic trough and Qinling oceanic trough formed a united basin and the centre uplift zone was developed to a platform margin , the west of the centre uplift zone was developed to a basin and a slope and the east of the centre uplift zone was developed to a broad lagoon during the biggest sea water invasion in Ma4 stage. Ordos Basin was isolated from exterior sea and the salty lagoon was changed to a salt lake gradually during Ma5 stage owing to sea level descend and barrier of the centre uplift zone. In Ma6 stage the Basin was changed to a broad lagoon. Based on the pioneer research of paleo-structure, paleo-geography, paleo-hydrodynamic as well as paleo-climate, a new

  20. 鄂尔多斯盆地新街地区直罗组地层铀矿成矿环境分析%Zhiluo formation uranium mineralization environmental analysis in New Street area Ordos Basin



    砂岩型铀矿床主要受地层砂体沉积环境控制。文章从岩性组合、沉积构造、岩石化学成分、粒度分析、砂体规模等多方面研究了含矿地层直罗组的沉积环境特征。直罗组的砂岩具有板状交错层理及槽状交错层理发育,显示其辫状河流相沉积特征;依据粒度分析,存在分支河道及心滩亚相沉积。岩石砂体分选性中等—好,成熟度较高,表明其物源较远,沉积物经过长距离的搬运才沉积下来;由砂岩化学成分铁的含量分析表明直罗组沉积环境为还原环境,后期遭受不同程度后生氧化。因此,本区直罗组沉积环境为还原环境下远源砂质辫状河沉积环境,铀矿化受辫状河的心滩及分支河道亚相砂体控制。具有较好砂岩铀矿成矿地质条件。%Sandstone-type uranium deposits are mainly controlled by the sand depositional environment. Articles from lithological combinations, sedimentary structures, rock chemical composition, particle size analysis, sand body size and other characteristics of various studies the depositional environment of Zhiluo Formation. Zhiluo Formation of the study area has a plate cross-bedded sandstone and trough cross-bedding development, display its braided fluvial sedimentary characteristics. According to particle size analysis, there is sub-branch channel and channel bar facies. Rock sand sorting is medium - good, high of maturity, indicating sediment deposition after long distance transport. The chemical composition of the iron content analysis sandstone Zhiluo Formation in reducing environment-based, but all suffer from varying degrees of epigenetic oxidation. Therefore, the district Zhiluo sedimentary environment under reducing environment distal sandy braided river depositional environments, uranium mineralization by heart subfacies Beach and distributary channel sand body control braided river. It has good geological conditions of Sandstone uranium

  1. Mineralogy and geochemistry of the No. 6 Coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China

    Dai, S.; Ren, D.; Chou, C.-L.; Li, S.; Jiang, Y.


    This paper discusses the mineralogy and geochemistry of the No. 6 Coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China. The results show that the vitrinite reflectance (0.58%) is lowest and the proportions of inertinite and liptinite (37.4% and 7.1%, respectively) in the No. 6 Coal of the Junger Coalfield are highest among all of the Late Paleozoic coals in the Ordos Basin. The No. 6 Coal may be divided vertically into four sections based on their mineral compositions and elemental concentrations. A high boehmite content (mean 6.1%) was identified in the No. 6 Coal. The minerals associated with the boehmite in the coal include goyazite, rutile, zircon, and Pb-bearing minerals (galena, clausthalite, and selenio-galena). The boehmite is derived from weathered and oxidized bauxite in the weathered crust of the underlying Benxi Formation (Pennsylvanian). A high Pb-bearing mineral content of samples ZG6-2 and ZG6-3 is likely of hydrothermal origin. The No. 6 coal is enriched in Ga (44.8 ??g/g), Se (8.2 ??g/g), Sr (423 ??g/g), Zr (234 ??g/g), REEs (193.3 ??g/g), Hg (0.35 ??g/g), Pb (35.7 ??g/ g), and Th (17.8 ??g/g). Gallium and Th in the No. 6 Coal mainly occur in boehmite, and the Pb-bearing selenide and sulfide minerals contribute not only to Se and Pb contents in the coal, but also probably to Hg content. A high Zr content is attributed to the presence of zircon, and Sr is related to goyazite. The REEs in the coal are supplied from the sediment-source region, and the REEs leached from the adjacent partings by groundwater. ?? 2005 Elsevier B.V. All rights reserved.

  2. Mineralogy and geochemistry of the No. 6 Coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China

    Dai, Shifeng [Key Laboratory of Resource Exploration Research of Hebei Province, Handan 056038 (China); Ren, Deyi; Li, Shengsheng; Jiang, Yaofa [China University of Mining and Technology, D11, Xueyuan Road, Haidian District, Beijing 100083 (China); Chou, Chen-Lin [Illinois State Geological Survey (Emeritus), 615 East Peabody Drive, Champaign, IL 61820 (United States)


    This paper discusses the mineralogy and geochemistry of the No. 6 Coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China. The results show that the vitrinite reflectance (0.58%) is lowest and the proportions of inertinite and liptinite (37.4% and 7.1%, respectively) in the No. 6 Coal of the Junger Coalfield are highest among all of the Late Paleozoic coals in the Ordos Basin. The No. 6 Coal may be divided vertically into four sections based on their mineral compositions and elemental concentrations. A high boehmite content (mean 6.1%) was identified in the No. 6 Coal. The minerals associated with the boehmite in the coal include goyazite, rutile, zircon, and Pb-bearing minerals (galena, clausthalite, and selenio-galena). The boehmite is derived from weathered and oxidized bauxite in the weathered crust of the underlying Benxi Formation (Pennsylvanian). A high Pb-bearing mineral content of samples ZG6-2 and ZG6-3 is likely of hydrothermal origin. The No. 6 coal is enriched in Ga (44.8 {mu}g/g), Se (8.2 {mu}g/g), Sr (423 {mu}g/g), Zr (234 {mu}g/g), REEs (193.3 {mu}g/g), Hg (0.35 {mu}g/g), Pb (35.7 {mu}g/g), and Th (17.8 {mu}g/g). Gallium and Th in the No. 6 Coal mainly occur in boehmite, and the Pb-bearing selenide and sulfide minerals contribute not only to Se and Pb contents in the coal, but also probably to Hg content. A high Zr content is attributed to the presence of zircon, and Sr is related to goyazite. The REEs in the coal are supplied from the sediment-source region, and the REEs leached from the adjacent partings by groundwater. (author)

  3. Palaeogeographic and Sedimentological Characteristics of the Triassic Chang 8,Ordos Basin,China%鄂尔多斯盆地长8油层组古地理环境与沉积特征

    刘化清; 李相博; 完颜容; 魏立花; 廖建波


    通过对地震、钻井资料的综合分析,认为延长组下部长8沉积时期鄂尔多斯湖盆可能不具有明显的"南陡北缓"的古地貌特征,也可能不存在大面积分布的半深湖—深湖环境。长8期湖盆古地形较为平坦,坡降不足0.1°或2m/km,气候较为干旱,湖泊水体为微咸水,水深小于10 m。具有如下特征的浅水湖泊三角洲为此时盆地的主体沉积类型:1)砂岩以中—细粒岩屑长石砂岩和长石岩屑砂岩为主;2)三角洲前缘延伸范围大(80~100 km),并频繁暴露;3)砂体主要为水下分支河道沉积成因;4)河口坝和重力流沉积不发育;5)吉尔伯特型三角洲具有的顶积、前积和底积三元结构在长8不发育。盆地南北古地形之间的显著差异出现在长8之后的长7早期,受印支运动及与盆地西南边缘毗邻的西秦岭强烈造山活动的影响,鄂尔多斯盆地的基底不对称挠曲变形,从而形成"南陡北缓"的盆地古地貌格局。从长7开始至晚三叠世末,盆内坡折带普遍发育,具有顶积、前积和底积三元结构的吉尔伯特型三角洲也就成为盆地内部最主要的沉积类型之一。%Data of seismic and bore hole show that the palaeotopography of the Triassic Chang 8,in the lower part of the Yanchang Formation,Ordos basin,was possibly not "steep to the south while gentle to the north" style as the previous studies suggested,and large areas of bathyal or abyssal areas were also impossible in this age.The bed form of the lake was very gentle on the basin scale with the slope angle no more than 0.1°,or 2 m/km.The climate was possibly a little dry and the mildly brackish water with depth no more than 10m was the dominant media of the sediments.Vertical or high angel burrows and root systems,coal seams or coaly mudstones and plant fossils of Neocalamites are commonly inclusions either at the edge or in the center of the basin.Shallow lacustrine delta with the

  4. 鄂尔多斯盆地中东部马五段碳酸盐岩气藏富气主控因素以陕200井区为例%Main Controlling Factors of Natural Gas Accumulation in Carbonate in Fifth Member of Ordovician Majiagou Formation,Mid-Eastern Ordos Basin:Take Well Shaan 200 Area as a Study Example

    徐波; 唐铁柱; 李辰


    靖边气田是中国最早发现的海相碳酸盐岩气藏之一,目前勘探范围仍在不断扩大。在回顾历年勘探和研究的基础上,以靖边气田陕200井区为例,总结和探讨了鄂尔多斯盆地中东部奥陶系碳酸盐岩储层富气的主控因素,以期为进一步勘探开发提供合理建议。研究表明:构造演变是靖边气田成藏的前提,决定了气田的分布范围和产气层位;沟槽的分布位置和切割深度对马五气藏的富集程度有着重要影响,鼻状构造不是主控因素。沉积环境是形成有利储层岩石类型的先决条件,潮间带云坪、潮上带膏云坪和含膏云坪微相是有利沉积微相。建设性的成岩作用是形成有利储集空间的重要保证,研究区多期溶蚀、白云化等建设性成岩作用对储层质量的改进较大,其中多期溶蚀作用是形成优质储集空间的主要成因。裂缝是天然气富集的重要因素,但裂缝发育程度因层位而不同。孔、洞、缝及沟槽的有效配置受构造、沉积、成岩作用的控制,每个层段的储集性能和天然气的富气程度不同。%Jingbian gas field is one of the earliest marine carbonate gas reservoirs discovered in China ,and its exploration area has been enlarging .Taking Well Shan 200 and its surrounding area as a study example , we discuss the main controlling factors of natural gas accumulation in Ordovician carbonate reservoir in the mid‐eastern Ordos basin ,and summarize the results as below :1)The tectonic evolution of Jingbian gas field is the premise of gas accumulation .It determines the gas‐field distribution range and the gas production layer . The location and cutting depth of the ancient valleys have a significant impact on the enrichment degree of Ma 5 gas reservoir .The nose structure is not the main controlling factor . 2 ) The sedimentary environment is a prerequisite for the formation of favorable reservoir rock .The

  5. Geochemical Characteristics,Sedimentary Environment and Tectonic Setting of Huangqikou Formation,Ordos Basin%鄂尔多斯地区黄旗口组地球化学特征及其沉积环境与构造背景

    宋立军; 刘池阳; 赵红格; 王建强; 张小龙


    A set of ultra-thick Middle Proterozoic clastic sedimentary rocks deposited in and around southwestern Ordos basin, with the Huangqikou Formation(HKF)as the most typical one,has great potential for oil and gas exploration.However,our understanding of HKF needs to be enhanced.Thus,by means of main-trace,rare elements and detrital component method,we probed into the sedimentary environment and tectonic setting of the HKF.The sedimentary environment discrimination dia-grams of both main and trace elements show that the HKF was deposited wholly under a dry environment with fresh water oxi-dized,or an oxygen-enriched environment,with an average paleoseawater temperature of 32 ℃.The tectonic environment dis-crimination diagrams of clastic composition,and main and trace elements all show similarity to those of the East African rift ba-sin,and gradual increasing of the quartz sandstone content from the lower to the upper parts,suggesting that HKF deposited under an intracontinental rift tectonic-sedimentary setting,which may have been caused by the counterclockwise rotation of North China Craton.It is concluded that the HKF was deposited in an intracontinental rift basin in the fresh water,and the tectonic setting became more stable from early to late stage,which was intra-continental rift in the early stage and post-rift depression in the late one.%鄂尔多斯盆地西南部及邻区沉积了一套以黄旗口组为代表的巨厚的中元古界碎屑岩系,该套地层具有重要的油气勘探潜力,但目前人们对该套地层的勘探认识尚不够深入,利用碎屑组分、主微量、稀土元素等地球化学手段,结合区域及深部背景特征,探讨了该套地层形成时期的沉积环境和构造背景。结果显示,黄旗口组整体形成于气候干燥的淡水氧化或富氧的过渡环境,沉积期古海水温度较高(平均为32℃);黄旗口组碎屑组分及其主微量元素特征与东非裂谷区相似,加之

  6. 基于层序地层模拟的湖岸线迁移对层序定量识别的指示:以鄂尔多斯盆地山2段为例%Quantitative Recognition of Sequence Stratigraphic Units Based on Lacustrine Shoreline Migration Used Sequence Stratigraphic Simulation: Example from the Member 2 of Shanxi Formation, Ordos Basin

    刘强虎; 朱红涛; 李敏; Keyu Liu


    Lacustrine shoreline is the boundary between the onshore deposits and the subaqueous deposits. This study uses the SEDPAK two-dimensional sequence modeling program to discuss the relationship between the migration and the sequence, member 2 of Shanxi Formation in Ordos Basin as the conceptual geological model. The lacustrine shoreline is redefined and re-classified in horizontal and vertical directions. The landward migration of lacustrine shoreline has been redefined as 'positive', which is equated with the process of transgression. On the contrary, the process of basin-ward migration has been redefined as 'negative' , corresponding to the process of regression. In the process of negative movement, the upward migration of the lacustrine shoreline has been redefined as 'codirectional', which is equated with the process of normal regression. In contrast, the process of downward migration has been redefined as 'reverse', corresponding to the process of forced regression. The interface of lacustrine shoreline from positive to negative corresponds to the maximum flooding surface, while the interface corresponds to the maximum regression surface. During the stage of negative movement, the interface of lacustrine shoreline from the codirectional to reverse has been equated with the forced regression bottom surface, whereas the interface is equated with the correlative conformity.%湖岸线是水陆沉积的分界线,为探讨其迁移规律与层序间的关系,利用SEDPAK二维层序模拟软件,以鄂尔多斯盆地山2段作为地质原型,对湖岸线迁移进行了定量模拟,进而提出了其可以有效指示层序及内部体系域识别的新认识.对湖岸线迁移规律在水平方向与垂直方向重新进行了划分、定义.在水平方向上,向物源区方向的迁移定义为“正向”,对应于湖侵过程;向盆地方向的迁移定义为“负向”,对应于湖退过程.“负向”迁移在垂向上可细分为向上方迁移的“同向

  7. 鄂尔多斯盆地西北部盒8段浅水三角洲砂体成因及分布模式%Genesis and distribution pattern of shallow water delta sandbodies in Member 8 of Lower Shihezi Formation in the northwest of Ordos Basin

    李洁; 陈洪德; 林良彪; 苏中堂; 张成弓; 程立雪; 彭传利


    鄂尔多斯盆地西北部下石盒子组盒8段(简称:盒8段),整体具有构造稳定、沉降缓慢、盆大、坡缓、水浅、源多的特点,广泛发育缓坡型浅水辫状河三角洲沉积.运用地层过程-响应沉积动力学原理和高分辨率层序地层学的理论及方法,对该类三角洲砂体的成因与组合类型进行了探讨.该时期砂体明显受基准面升降旋回过程中可容纳空同和沉积物补给通量比值变化的控制,可划分为进积型、加积型.进积型主要由高能削截武河道砂体、低能削截式河道砂体、残缺式埙上河砂体构成;加积型则主要由低能削截武河道砂体、完整式河道砂体、下残式坝上河砂体构成.结合砂体的时空展布规律,建立了缓坡型浅水辫状河三角洲砂体成因分布模式.层序界面上的高能河道砂体富集岩性油气藏,勘探潜力大.%Member 8 of Lower Shihezi Formation in the northwest of Ordos Basin is characterized by the regional tectonic setting with steady and slow subsidence, large area, gentle slope, relatively shallow water and multiple sources. The gentle slope-type shallow braided river delta is developed. The author takes the stratigraphic and sedimentary process-response dynamic principles as a theoretical basis, and uses the theory and technology of the high-resolution sequence stratigraphy to explore the genetic combination types of this kind of delta sandbodies. The sandbodies were evidently influenced by the relation between accommodations and sediment alimentations during the base-level up and down changes. The sandbodies in Member 8 consists of two vertical superposed types of progradation model and aggradation model from bottom to top. The progradation model mainly includes high-energy truncation style channels, low-energy truncation style channels, and deformity recombination which mouses bars at the bottom and under water distributary channels at the top; The aggradation model mainly

  8. The Evaluation of Eco-environmental Sensitivity in Ordos City

    Yanhong; XU; Xijun; YAO; Libo; LU; Haijiao; FAN


    This paper aims to reveal the difference of eco-environmental sensitivity and its influencing factors in the study area through carrying out the eco-environmental sensitivity evaluation based on land ecological security for 8 counties of Ordos City. Using fragstats landscape pattern analysis,GIS space method and RS analysis,based on ground investigation,this paper uses information mining and data analysis to extract index data for every village in the study area,carry out comprehensive quantitative evaluation,and finally calculate the comprehensive scores of eco-environmental sensitivity of the areas. The paper concludes that the highly sensitive areas and extremely sensitive areas are mainly concentrated in the eastern region of the eastern hilly and gully region and southern region of the Mu Us Desert in Ordos. The main reasons include severe soil erosion in hilly and gully region and serious desertification in southern Mu Us Desert area. So it is necessary to strengthen ecological environment protection in local areas.

  9. seismic space-time transformation of the periphery of the Ordos block

    Qi, D.; Ping, L. C.; Yun, S.


    Ordos block is located on the eastern edge of the north-south seismic belt, northeastern margin of the Qinghai-Tibet Plateau, the transfer of three plates of north China, south China and Qinghai-Tibet. Its internal structure is stable, on which earthquakes rarely occur, but the periphery has strong new tectonic movements on it. Research on the periphery of Ordos block seismic activity and transformation of time and space carried out new ideas of earthquake prediction for the area. This paper plots Ordos earthquake catalog data according to existing data, combined with the distribution of active tectonics, using GIS tools statistical regularity, analyze the seismic migration characteristics, earthquake recurrence interval, and predict future earthquake risk zone. In combination of the transformation of spatial and temporal periphery of the Ordos block seismic activity, we draw a conclusion : 1.The moderate earthquakes migrate from the northeastern margin to the southwestern margin of the Ordos, different magnitude earthquakes have different migration cycles. 2.The intensity of the periphery of the seismic activity was significantly higher than the north and south edge, but the north and south edge has higher risk of large earthquake. 3. Different earthquake fault zones has different migration of earthquakes, existing on the same directional migration, and migration between different fault zone. Key words: Ordos block; Seismic time-space transformation; earthquake tectonic movement.

  10. A discovery of extremely-enriched boehmite from coal in the Junger Coalfield, the northeastern Ordos Basin

    Dai, S.; Ren, D.; Li, S.; Chou, C.


    The authors found an extremely-enriched boehmite and its associated minerals for the first time in the super-thick No. 6 coal seam from the Junger Coalfield in the northeastern Ordos Basin by using technologies including the X-ray diffraction analysis (XRD), scanning electron microscope equipped with an energy dispersive X-ray spectrometer, and optical microscope. The content of boehmite is as high as 13.1%, and the associated minerals are goyazite, zircon, rutile, goethite, galena, clausthalite, and selenio-galena. The heavy minerals assemblage is similar to that in the bauxite of the Benxi Formation from North China. The high boehmite in coal is mainly from weathering crust bauxite of the Benxi Formation from the northeastern coal-accumulation basin. The gibbsite colloidstone solution was removed from bauxite to the peat mire, and boehmite was formed via compaction and dehydration of gibbsite colloidstone solution in the period of peat accumulation and early period of diagenesis.

  11. CO2 breakthrough pressure and permeability for unsaturated low-permeability sandstone of the Ordos Basin

    Zhao, Yan; Yu, Qingchun


    With rising threats from greenhouse gases, capture and injection of CO2 into suitable underground formations is being considered as a method to reduce anthropogenic emissions of CO2 to the atmosphere. As the injected CO2 will remain in storage for hundreds of years, the safety of CO2 geologic sequestration is a major concern. The low-permeability sandstone of the Ordos Basin in China is regarded as both caprock and reservoir rock, so understanding the breakthrough pressure and permeability of the rock is necessary. Because part of the pore volume experiences a non-wetting phase during the CO2 injection and migration process, the rock may be in an unsaturated condition. And if accidental leakage occurs, CO2 will migrate up into the unsaturated zone. In this study, breakthrough experiments were performed at various degrees of water saturation with five core samples of low-permeability sandstone obtained from the Ordos Basin. The experiments were conducted at 40 °C and pressures of >8 MPa to simulate the geological conditions for CO2 sequestration. The results indicate that the degree of water saturation and the pore structure are the main factors affecting the rock breakthrough pressure and permeability, since the influence of calcite dissolution and clay mineral swelling during the saturation process is excluded. Increasing the average pore radius or most probable pore radius leads to a reduction in the breakthrough pressure and an increase by several orders of magnitude in scCO2 effective permeability. In addition, the breakthrough pressure rises and the scCO2 effective permeability decreases when the water saturation increases. However, when the average pore radius is greater than 0.151 μm, the degree of water saturation will has a little effect on the breakthrough pressure. On this foundation, if the most probable pore radius of the core sample reaches 1.760 μm, the breakthrough pressure will not be impacted by the increasing water saturation. We establish

  12. The relationship between dolomitization and organic matter occurrence in Lower Paleozoic carbonate in the Ordos Basin


    Based on observations on the core and surface sections of Lower Paleozoic carbonate in the Ordos Basin, petrography research and measurements of TOC, TOS , Ro, XRD, and comparative study with dolomite in modern Coorong Lake, it has been revealed that: (i)dolomitization may occur in micrite limestone, gypsum-halite and argillaceous sandstone, and it can be divided into three types: sedimentary penecontemporaneous-early diagenesis, late diagenesis of deep burial and catagenesis of uplift period. However, the crystal cell of the second type less than 35 μ m in size is most closely associated with gas pool; (ii) the highest content of organic matter (OM) is produced in samples from the argillic dolomite which may be formed by argillaceous fluid through gypsum-halite; (iii) in the evolution process from penecontemporaneous dolomite into stoichiometric dolomite, the crystal order of dolomite and the porosity of its host rock tend to increase, which is favorable to the formation of an available migration network. When the power of the fluid is high enough, the network is mainly favorable to the migration and transport of heat, but when the power of the fluid goes down, the network system is favorable, due to its large space, to OM deposition in it.

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

    Shengli Xi


    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.

  14. 储层沥青成因及其对油气运聚的影响——以鄂尔多斯盆地华庆地区长8油层组1砂组为例%Reservoir bitumen genesis and its impacts on hydrocarbon migration and accumulation:a case study from Chang 81 of Yangchang Fomation in Huaqing area, the Ordos Basin

    陈世加; 姚泾利; 路俊刚; 杨国平; 文延春; 张纪智; 石正灏


    Bitumen is common in the pores of Chang 8 pay zone of the Triassic Yanchang Formation in Huaqing area of the central part of Ordos Basin, and the oil-water relationship is very complicated. According to the analysis on the geochemical characteristics of reservoir extracts and crude oil, combining with comparative test on the reservoir physical property of cores containing bitumen before and after washing oil and the reservoir fluorescence analysis, authors studies in detail the reservoir bitumen genesis and its impact on reservoir physical property and hydrocarbon migration and accumulation in this area. The results show that the genesis of reservoir bitumen and crude oil are different, and the bitumen has lower maturity with strong biodegradation. Base on the experiment of washing oil, it is found that both the post-washing porosity and permeability of cores containing bitumen increase significantly, and the oil formed in late stage mainly distributes in the residual pore filled with bitumen. It is pointed out that bitumen has an important control on reservoir physical property and hydrocarbon migration andaccumulation at late stage. The Chang 81 formation experienced hydrocarbon two accumulation stages,the first stage happened in Middle-Late Jurassic and the second in Early Cretaceous. The early accumulated crude oil with low maturity suffered from strong biodegradation and were turned to bitumen,which filled in the pores of reservoir together with chlorites and ferrocalcites, making the reservoir tighter. The mature oil generated from the source rocks in late stage could only accumulate in the residual pores filled with bitumen or in pores of reservoir with less bitumen.%鄂尔多斯盆地中部华庆地区三叠系延长组长8油层组1砂组储层孔隙中普遍见沥青,油水关系十分复杂.通过对储层抽提物和原油的地球化学特征分析,并结合含沥青岩心洗油前后储层物性对比实验和储层显微荧光分析,系统研究了

  15. Comprehensive geochemical identification of highly evolved marine carbonate rocks as hydrocarbon-source rocks as exemplified by the Ordos Basin


    This study reversed the developing environments of hydrocarbon-source rocks in the Ordos Basin and evaluated carbonate rocks as hydrocarbon-source rocks and their distributions on account of the fact that China's marine carbonate rocks as hydrocarbon-source rocks are characterized by intensive thermal evolution and relatively low abundance of organic matter, by taking the Lower Paleozoic of the Ordos Basin for example and in light of the calculated enrichment coefficients of trace elements, the REE distribution patterns, the mathematical statistics analysis of elements and carbon isotopes and their three-dimensional diagrammatization in combination with the necessary organic parameters. As for the Ordos Basin, TOC=0.2% is an important boundary value. Studies have shown that in the strata where TOC is greater than 0.2%, Ba is highly enriched with positive δ13Ccarb shifts and δ13Corg less than -28‰, reflecting a thigh paleo-productivity, high burial amounts of organic matter, relatively good hydrocarbon-generating potentiality and intensive REE fractionation. All these indicated that the settlement rates are low and the geological conditions are good for the preservation of organic matter, hence favoring the development of hydrocarbon-source rocks. The Klimory and Wulalik formations show certain regularities in those aspects and, therefore, they can be regarded as the potential effective hydrocarbon-source rocks. In the strata where total TOC is less than 0.2%, the contents of Ba are low, δ13Ccarb values are mostly negative, and δ13Corg values range from -24‰--28‰, demonstrating low burial amounts of organic matter, poor potentialities of hydrocarbon generation, weak REE fractionation and rapid settlement rates. These facts showed that most of the hydrocarbon-source rocks were formed in shallow-water, high-energy oxidizing environments, thus unfavoring the development of hydrocarbon-source rocks. It is feasible to make use of the geochemical method to

  16. Application of mercury injection and rate-controlled mercury penetration in quantitative characterization of microscopic pore structure of tight reservoirs:A case study of the Chang7 reservoir in Huachi-Heshui area, the Ordos Basin%压汞-恒速压汞在致密储层微观孔喉结构定量表征中的应用--以鄂尔多斯盆地华池-合水地区长7储层为例

    喻建; 马捷; 路俊刚; 曹琰; 冯胜斌; 李卫成


    Huachi-Heshui area in the Ordos Basin is a typical enrichment region for tight reservoirs. It has poor physical properties and complicated characteristics of microscopic pore throat structure, which has a great effect on oil and gas accumulation and exploitation. Mercury injection and rate⁃controlled mercury penetration were used to quantitatively characterize nanometer pore throats and to study fluid mobility characteristics in tight sandstone reser⁃voirs in the seventh member of the Yanchang Formation (Chang7). The reservoir in the study area has high dis⁃placement pressure, low average throat radius, large pore/throat volume ratio, big pore throat and poor permeability. The distribution range of pore radius of rock samples with different properties is consistent, while the distribution of throat geometry among them is obviously different. Mercury injection saturation increases with the increase of pore numbers. The curve of SHg-ΔSHg/ΔPc can preferably reflect mercury injection velocity and pore throat structure. Nanometer throat pore sare well developed in tight reservoirs, which make a great contribution to reservoir capacity and permeability. In the course of injection, fluid first enters the main controlling area of the pore, then the common control area of pore and throat, and finally the main control area of the throat. Rate⁃controlled mercury penetration is useful for the reservoirs with good physical properties, but it can not reflect the characteristics of nanometer pore throats in studying the pore throat structure of tight reservoirs.%鄂尔多斯盆地华池—合水地区是典型的致密油气富集区,储层物性差,微观孔喉结构特征复杂,孔喉结构对油气的富集和后期开采有较大影响。利用压汞—恒速压汞法探讨华池—合水地区延长组长7致密砂岩储层纳米孔喉定量表征及孔喉体系中流体渗流特征。研究表明:研究区储层排替压力较高,平均喉道半径较

  17. Base-Level Cycles and Episodic Coal Accumulation——Case Study of Dongsheng Coalfield in Ordos Basin

    YANG Ren-chao; HAN Zuo-zhen; LI Zeng-xue; FAN Ai-ping


    The advantage of high-resolution sequence stratigraphy, which takes base-levels as reference, is that it can be applied to continental depositional basins controlled by multiple factors and can effectively improve the accuracy and resolution of sequential stratigraphic analysis. Moreover, the principles of base-level cycles are also suitable for analyzing sequential stratigraphy in continental coal-bearing basins because of their accuracy in forecasting distribution of coal measures. By taking the Dongsheng coalfield in the Ordos basin as an example, the extensive application of base-level cycles in exploration and exploitation of coal is analyzed. The result shows that the Yan'an formation in the Dongsheng area is a long-term base-level cycle which is bordered by nonconformities and made up of five mid-term cycles and 13 short-term cycles. The long-term cycle and the mid-term cycles are obvious in comparison with a transverse profile. The episodic coal accumulation in the Mesozoic Ordos basin means that the deposition of primary matter (peat bogs) of coalification is discontinuous, periodical and cyclical in the evolution of the basin. The episodic accumulation of coal measures in the Yan'an stage is controlled by ascending-descending changes of a long-term cycle and middle-term cycles. Coal measures formed during the early and late periods of the long-term cycle are characterized by multiple layers, big cumulative thickness and poor continuity. Coal measures formed in the mid-term of the long cycle are dominated by good continuity, fewer layers and a small additive thickness, which is favorable for the accumulation of thick and continuous coal measures in the transition stage of mid term base-level cycles.

  18. Potential evaluation of CO2 storage and enhanced oil recovery of tight oil reservoir in the Ordos Basin, China.

    Tian, Xiaofeng; Cheng, Linsong; Cao, Renyi; Zhang, Miaoyi; Guo, Qiang; Wang, Yimin; Zhang, Jian; Cui, Yu


    Carbon -di-oxide (CO2) is regarded as the most important greenhouse gas to accelerate climate change and ocean acidification. The Chinese government is seeking methods to reduce anthropogenic CO2 gas emission. CO2 capture and geological storage is one of the main methods. In addition, injecting CO2 is also an effective method to replenish formation energy in developing tight oil reservoirs. However, exiting methods to estimate CO2 storage capacity are all based on the material balance theory. This was absolutely correct for normal reservoirs. However, as natural fractures widely exist in tight oil reservoirs and majority of them are vertical ones, tight oil reservoirs are not close. Therefore, material balance theory is not adaptive. In the present study, a new method to calculate CO2 storage capacity is presented. The CO2 effective storage capacity, in this new method, consisted of free CO2, CO2 dissolved in oil and CO2 dissolved in water. Case studies of tight oil reservoir from Ordos Basin was conducted and it was found that due to far lower viscosity of CO2 and larger solubility in oil, CO2 could flow in tight oil reservoirs more easily. As a result, injecting CO2 in tight oil reservoirs could obviously enhance sweep efficiency by 24.5% and oil recovery efficiency by 7.5%. CO2 effective storage capacity of Chang 7 tight oil reservoir in Longdong area was 1.88 x 10(7) t. The Chang 7 tight oil reservoir in Ordos Basin was estimated to be 6.38 x 10(11) t. As tight oil reservoirs were widely distributed in Songliao Basin, Sichuan Basin and so on, geological storage capacity of CO2 in China is potential.

  19. On the analysis of the high-resolution sequence stratigraphy and coal accumulating law of jurassic in Ordos Basin

    LI Zeng-xue; HAN Mei-lian; LI Jiang-tao; YU Ji-feng; L(U) Da-wei; LIU Han-feng


    The strata of Jurassic was divided into three tectonic sequences and eight se-quences of third rank, according to the developing feature of the tectonic inconformity and the transforming feature of the depositional system tracts. Also the identification and the division of the base-level cycle of different period were carded through. Therefore three cycles of super period, eight cycles of long period, twenty-four cycles of middle period and some cycles of short pedod were identified. From the overall character of the coal-accu-mulation in the Mesozoic, we can see that the Yan'an formation is of the best nature of coal bearing. When the coal bearing systems of Jurassic were depositing, the Ordos area is the coal accumulating basin of terrene of large scale and located in the same tectonic unit. But the local structure of different part and the paleolandform are different in the basin,which resulted in the difference of the depositional environment. So the layer number and the distribution of the thickness of the coal beds are different in the different part of the ba-sin. The coal-accumulating action migrated regularly along with the development, evolve-ment and migration of the depositional systems. The layer numbers of the coal beds,which can be mined, are more in the north and west fringe of the basin, whose distributing area is extensive, and they are more steady in the landscape orientation, also the total thickness is great. Therefore the nature of coal bearing and the coal-accumulating action of different part changed obviously in the space in Ordos area.

  20. [Responses of spatial distribution pattern of Artemisia ordosica population to the precipitation gradient on Ordos Plateau].

    Li, Qiu-shuang; Zhang, Chao; Wang, Fei; Lai, Li-ming; Zhang, Li; Li, Wen-ting; Bai, Hua; Zheng, Yuan-run


    Five sites along the precipitation gradient (336-249 mm x a(-1)) from east to west in Ordos Plateau were selected to study the spatial distribution pattern of Artemisia ordosica population and its responses to the precipitation gradient by the methods of variance mean ratio, aggregative index, and point pattern analysis. The reduction of precipitation affected the spatial distribution pattern of A. ordosica population significantly. With decreasing precipitation gradient, the spatial pattern of A. ordosica population changed from uniform to random in small scale, and from random to clumpy in large scale, suggesting that in the ecological restoration of Ordos Plateau, a rational arrangement of A. ordosica should be made.

  1. Assessment of undiscovered continuous gas resources of the Ordos Basin Province, China, 2015

    Charpentier, Ronald R.; Klett, Timothy R.; Schenk, Christopher J.; Brownfield, Michael E.; Gaswirth, Stephanie B.; Le, Phuong A.; Leathers-Miller, Heidi M.; Marra, Kristen R.; Mercier, Tracey J.


    Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean resources of 28 trillion cubic feet of tight gas and 5.6 trillion cubic feet of coalbed gas in upper Paleozoic rocks in the Ordos Basin Province, China.

  2. Effects of climatic gradients on genetic differentiation of Caragana on the Ordos Plateau, China

    Jiuyan Yang; Samuel A. Cushman; Jie Yang; Mingbo Yang; Tiejun Bao


    The genus Caragana (Fabr.) in the Ordos Plateau of Inner Mongolia, China, provides a strong opportunity to investigate patterns of genetic differentiation along steep climatic gradients, and to identify the environmental factors most likely to be responsible for driving the radiation. This study used a factorial, multi-model approach to evaluate alternative hypotheses...

  3. 鄂尔多斯盆地白豹地区长6储层油水识别及影响因素分析%Recognition Technology of the Complicated oil and Water Layers in Chang 6 Bearing Formation of Baibao Area

    巨银娟; 张小莉


    The 6 th section of the upper Triassic Yanchang formation is the most important reservoir in the Ordos basin. Reservoir lithology is thin and tight muddy siltstone in the deep lake facies,The 6 th section is a typical compact oil reservoir that has abundant slump deposition,which led to the oil reservoir heterogeneousness and the difficulty of reservoir evaluation. this paper analyzed influential factor of log responses in terms of the pore complex structure led to increased water saturation and high water salinity ,high clay content and the presence of radioactive sandstone . in the calibration with actual test data of 43 well,based on the study of lithology,physical property,diagrams of(△t ×(USP/SSP)×(1 -△GR)versus electric-resistivity( Rt)and sound wave time difference( AC)versus electric-resistivity( Rt)can clearly divide the field of oli,wa-ter and dry layer. Then,this type of diagram is suitable for the well logging interpretation of the 6 th section of Yanchang forma-tion in Baibao area. log interpretation of the oil-water distribution patterns,create a suitable evaluation criterion and explain model of the studied reservoir have great significance for the oil field exploration.%延长组长6段是鄂尔多斯盆地白豹地区的主要含油层位,储层岩性为近深湖相带薄而致密的泥质粉砂岩,其中大量发育的滑塌沉积进一步增加了储层非均质性和评价难度;为建立适合长6储层的油水识别标准及方法,从粘土成分、成岩作用、孔隙结构、地层水矿化度4方面分析其测井特征的影响因素,在143口井长6段试油资料标定下,分析含油性与测井参数或测井组合参数的响应关系。结果表明选用综合反映储层物性特征的组合参数(△t ×(USP/SSP)×(1-△GR))与深感应曲线 LID(地层真电阻率 Rt)制作交会图,能较好的区分出油层与非油层;在此基础上编制AC-Rt交会图可进一步将水层、干层和

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

    Yang Renchao; Fan Aiping; Han Zuozhen; Wang Xiuping


    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. Diagenetic facies types and logging identification methods for low-permeability tight sandstone reservoirs:a case study on the 8th member of Xiashihezi Formation in Sulige gasfieid, Ordos Basin%低渗透致密砂岩储层成岩相类型及测井识别方法——以鄂尔多斯盆地苏里格气田下石盒子组8段为例

    张海涛; 时卓; 石玉江; 王亮亮; 贺陆军


    Sulige gasfield in Ordos Basin is a typical tight gas reservoir. According to clastic constituents, diagenetic mineral assemblage,interstitial matter,and diagenesis types,et al,we identified 6 diagenetic faceis types in the 8 th member of Xiashihezi Formation ( He8 ) reservoir of Sulige gas field, including intergranular pore + strong solutional phase of volcanic material, intercrystal pore + solutional phase of volcanic material, intercrystal pore + solutional phase of debirs, intercrystal pore + cementation phase of quartz, hydromica cementation + weak solutional phase of debris and compaction + cementation tight phase. In addition,we analyzed the impacts of different digenesis on log responses. On the basis of these studies,a method for continuously and quantitatively identifying diagenetic facics was established by using gamma ray, interval transit time, density and deep lateral resistivity log data. Logging data of Well Z65 were processed with this method ,and a comparison with the thin section data and mercury injection data show that the results are accurate. Based on single well diagenetic facies identification, we defined the diagenetic face distribution in He8 reservoirs of Sulige gasfield. The central part of the gas field is dominated by intergranular pore + strong solutional phase of volcanic material and intercrystal pore + solutional phase of volcanic material, which are the favorable diagenetic faces belts.%鄂尔多斯盆地苏里格气田是低渗透致密砂岩气藏的典型代表,根据碎屑成分、成岩矿物组合、填隙物成分、成岩作用类型等特征,将苏里格气田盒8段储层划分为粒间孔+火山物质强溶蚀相、晶间孔+火山物质溶蚀相、晶间孔+岩屑溶蚀相、晶间孔+石英加大胶结相、水云母胶结+岩屑微溶蚀相和压实胶结致密成岩相6种成岩相类型,分析了不同成岩作用对测井响应的影响.在此基础上,通过自然伽马、声波时差、密度及深侧向测

  6. Tectonic Constraints on the Transformation of Paleozoic Framework of Uplift and Depression in the Ordos Area

    WANG Qingfei; DENG Jun; HUANG Dinghua; YANG Liqiang; GAO Bangfei; XU Hao; JIANG Shaoqing


    During the Paleozoic, the Ordos area in the western North China Plate was located at the intersecting position of microplates and controlled by their interaction. The structural framework in the Ordos area, which underwent transformations in the Ordovician, the Carboniferous and the Permian respectively, was dominated by the alternation of uplift and depression. The transformations of structural framework are utilized as the clues to investigate the microplates' interacting type and its response in the Ordos area. According to the regional structural evolution, the Ordos area is simplified into an isopachous, isotropic and elastic shell model, and under proposed various boundary conditions,three series of numerical simulations corresponding to the three structural transformations are carried out to determine the detailed tectonic constraints. Numerical simulations reveal that the structure of the uplift and depression, which is similar to the actual pattern, develops only under one special boundary condition in each of the three series, indicating that the structural framework responds to the unique tectonic background. The simulation results show that in the Early Paleozoic, the L-shaped paleouplift formed nearby the southwestern corner of the Ordos area because the intensity of the compressions in the southern and western boundaries resulting from the ocean-continent collisions was similar. In the Late Paleozoic, it evolved into continent-continent (or arc-continent) interaction in the southern and northern boundaries; in the preliminary stage of the interaction, since the interface between the North China Plate and the plates on the south and north was narrow, the relative acting force was little and the regional western boundary immobile, and the structural framework in the basin was characterized by the N-S trending slender-waist-shaped uplift; as the interface between the plates expanded gradually, the extrusive force in the southern and northern boundaries

  7. Geological characteristics and resource potentials of oil shale in Ordos Basin, Center China

    Yunlai, Bai; Yingcheng, Zhao; Long, Ma; Wu-jun, Wu; Yu-hu, Ma


    It has been shown that not only there are abundant oil, gas, coal, coal-bed gas, groundwater and giant uranium deposits but also there are abundant oil shale resources in Ordos basin. It has been shown also that the thickness of oil shale is, usually, 4-36m, oil-bearing 1.5%-13.7%, caloric value 1.66-20.98MJ/kg. The resource amount of oil shale with burial depth less than 2000 m is over 2000x108t (334). Within it, confirmed reserve is about 1x108t (121). Not only huge economic benefit but also precious experience in developing oil shale may be obtained in Ordos basin.

  8. The influence of large-scale climate phenomena on precipitation in the Ordos Basin, China

    Zhong, Yu; Lei, Liyuan; Liu, Youcun; Hao, Yonghong; Zou, Chris; Zhan, Hongbin


    Large-scale atmospheric circulations significantly affect regional precipitation patterns. However, it is not well known whether and how these phenomena affect regional precipitation distribution in northern China. This paper reported the individual and coupled effects of El Niño-Southern Oscillation (ENSO), Indian summer monsoon (ISM), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) on annual precipitation for the Ordos Basin, an arid and semi-arid basin, currently with major industries of coal, fossil oil, natural gas, and halite in north central China. Our results showed that ENSO and ISM exerted substantial impact on annual precipitation while the impact of PDO and AMO was relatively limited. There were 24 and 15 out of 33 stations showing significant differences (p planning and disaster management for the Ordos Basin.

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

    Shengli Xi; Xinshe Liu; Peilong Meng


    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...

  10. Assessing the relative role of climate change and human activities in sandy desertification of Ordos region, China


    Climate change and human activities are driving forces of sandy desertification and the relative role of them in sandy desertification is the hot point in related researches. A study was carried to assess the relative role of climate change and human activities in sandy desertification of Ordos region in China. Potential NPP and the difference between potential and actual NPP were selected as indicators to assess the relative role of climate change and human activities in sandy desertification, respectively. Assessing methods were built based on some scenarios for the reversion and expansion of sandy desertification and the relative role of climate change and human activities in sandy desertification of Ordos region were assessed from 1981 to 2000. The results showed that although some local places experienced an expansion of sandy desertification, the change of sandy desertification of Ordos region from 1981 to 2000 showed a stably reversing trend. The relative role of climate change and human activities in sandy desertification of Ordos region varied at different temporal and spatial scales in the reversion and expansion processes. In the reversion of sandy desertification, climate change was the dominant factor in the period of 1981 to 1990 and the reversed areas mainly induced by climate change including Mu Us sandy land and the transition zone between temperate steppe and temperate deciduous scrubs in north east of Ordos region; however, human activities controlled the reversed process during the period from 1991 to 2000 and the areas mainly induced by human activities distributed in all banners of Ordos region. In the expansion of sandy desertification, human activities were the dominant factor in the period of 1981 to 1990 and the expanded areas mainly included the regions around common boundary of Hanggin, Dalad Banners and Dongsheng City; however, climate change dominated the expansion of sandy desertification from 1991 to 2000, the expanded areas equably

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

    Wei Du; Zaixing Jiang; Qing Li; Ying Zhang


    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.

  12. Tectonic Evolution of the Tianhuan Depression and the Western Margin of the Late Triassic Ordos

    LI Xiangbo; LIU Huaqing; WANYAN Rong; WEI Lihua; LIAO Jianbo; FENG Ming; MA Yuhu; BAI Yunlai


    The Ordos Basin is one of the most important oil and gas basins in China. Based on surface outcrop, key exploratory wells and seismic reflection data and by using the technology of "prototype basin recovery", seismic profile "layer flattening" and "restoration of balanced section", and other methods, the sedimentary boundary, structure and the evolution history of the Tianhuan depression on the western margin of the Ordos Basin are reestablished. The following results have been obtained. (1) The west boundary of the Late Triassic Ordos Basin was far beyond the scope of the current basin. The basin is connected with the Late Triassic Hexi Corridor Basin, and its western margin did not have tectonic characteristics of a foreland basin. (2) The Tianhuan depression was first formed in the Late Jurassic. At the late stage it was impacted by the late Yanshanian and Himalayan tectonic movement and the depression axis gradually moved eastwards to the present location with a cumulative migration distance of ~30 kin. (3) Eastward migration of the depression axis caused adjustment and even destruction of the originally formed oil and gas reservoirs, so that oil and gas remigrated and aggregated, resulting in secondary structural reservoirs formed at high positions on the western flank of the depression.

  13. Origin of gray-green sandstone in ore bed of sandstone type uranium deposit in north Ordos Basin


    Dongsheng sandstone-type uranium deposit is located in the northern part of Ordos Basin, occurring in the transitional zones between gray-green and gray sandstones of Jurassic Zhiluo Formation. Sandstones in oxidized zone of the ore bed look gray-green, being of unique signature and different from one of ordinary inter-layered oxidation zone of sandstone-type uranium deposits. The character and origin of gray-green sandstones are systematically studied through their petrology, mineralogy and geochemistry. It is pointed out that this color of sandstones is originated from secondary oil-gas reduction processes after paleo-oxidation, being due to acicular-leaf chlorite covering surfaces of the sandstone grains. To find out the origin of gray-green sandstone and recognize paleo-oxidation zones in the ore bed are of not only theoretical significance for understanding metallogenesis of this kind of sandstone-type uranium deposit, but also very importantly practical significance for prospecting for similar kind of sandstone-type uranium deposit.

  14. Natural gas leakage of Mizhi gas reservoir in Ordos Basin, recorded by natural gas fluid inclusion


    Abundant natural gas inclusions were found in calcite veins filled in fractures of Central Fault Belt across the centre of Ordos Basin. Time of the calcite veins and characteristics of natural gas fluid inclusion were investigated by means of dating of thermolum luminescence (TL) and analyzing stable isotope of fluid inclusion. Results show that natural gas inclusion formed at 130―140℃ with salinity of 5.5 wt%―6.0 wt% NaCl. It indicates that natural gas inclusion is a kind of thermal hydrocarbon fluid formed within the basin. Method of opening inclusion by heating was used to analyze composition of fluid inclusion online, of which the maximal hydrocarbon gas content of fluid inclusion contained in veins is 2.4219 m3/t rock and the maximal C1/Σci ratio is 91%. Laser Raman spectroscopy (LRS) was used to analyze chemistry of individual fluid inclusion in which the maximal hydrocarbon gas content is 91.6% compared with little inorganic composition. Isotope analysis results of calcite veins show that they were deposited in fresh water, in which the δ13CPDB of calcite veins is from -5.75‰ to 15.23‰ andδ18OSMOW of calcite veins is from 21.33‰ to 21.67‰. Isotope results show thatδ13C1 PDB of natural gas fluid inclusion is from -21.36‰ to -29.06‰ and δDSMOW of that is from -70.89‰ to -111.03‰. It indicates that the gas of fluid inclusion formed from coal source rocks and it is the same as that of natural gas of Mizhi gas reservoir. Results of TL dating show that time of calcite vein is (32.4±3.42)×104 a, which is thought to be formation time of gas inclusion. It indicated that natural gas inclusion contained in calcite veins recorded natural gas leakage from Mizhi gas reservoir through the Central Fault Belt due to Himalayan tectonic movement.

  15. Densification Modes of Sandstone Reservoir in the 8th Member of the Lower Shihezi Formation,Permian,in Su-6 Area of Sulige Gas Field,Ordos Basin%鄂尔多斯盆地苏里格气田苏6区块二叠系下石盒子组8段砂岩储层致密成因模式

    毕明威; 刘金; 陈世悦; 周兆华; 郑国强; 张满郎; 高立祥; 钱爱华; 谷江锐; 石石


    Densification modes of tight sandstone reservoir of the 8th Member of Lower Shihezi Formation, Permian,in Su -6 Area of the Sulige Gas Field,Ordos Basin,are quantitatively analysised by means of slice identification,scan electron microscope,electron probe micro -analysis and energy spectrum,homogenization temperatures and raman microprobe research of fluid inclusions.The results are as follows:(1 )Densification process can be divided into the following stages,compaction during early diagenesis and the 1st stage siliceous cementation→—the 2nd stage siliceous cementat ion and grain -coating chlorite→—the 1st stage dissolution (hydrocarbon charge →—) compaction during late diagenesis and the 3rd stage siliceous cementation (densification of reservoir )→—the 2nd stage dissolution and the 4th stage sil iceous cementation→—cementation and replacement of chlorite→—cementation and replacement of carbonate.(2)Densification modes of reservoir can be divided into three types:densification of medium -coarse grained litharenite by strong compaction;densification of medium -coarse grained lithic quartzarenite by strong siliceous cementation and medium to strong compaction;densification of fine grained (feldspathic ) litharenite by strong compaction and medium to strong siliceous cementation.(3)The main reasons for densification of reservoir are compaction and siliceous cementation.And the 2nd stage dissolution under enclosed environment has less ascension of porosity,which is another important reason for densification.(4)The two types of medium -coarse grained sandstones are densification after hydrocarbon charge,which experience injection of organic acid and make dissolved pore to be the major storage space.Fine grained (feldspathic)litharenite is densification before hydrocarbon charge,which experience weak dissolution. (5)Difference of densification modes lead to the porosity,permeability ,correlation of permeability and porosity of medium -coarse

  16. Temporal and spatial analysis of vegetation coverage changes in Ordos area based on time series GIMMS-NDVI data

    Han, Ruimei; Zou, Youfeng; Ma, Chao; Liu, Pei


    Ordos area is the desert-wind erosion desertification steppe transition zone and the complex ecological zone. As the research area, Ordos City has the similar natural geographic environment to ShenDong coalfield. To research its ecological patterns and natural evolution law, it has instructive to reveal temporal and spatial changes of ecological environment with artificial disturbance in western mining. In this paper, a time series of AVHRR-NDVI(Normalized Difference Vegetation Index) data was used to monitor the change of vegetation temporal and spatial dynamics from 1981 to 2006 in Ordos City and ShenDong coalfield, where were as the research area. The MVC (Maximum Value Composites) method, average operation, linear regression, and gradation for NDVI change trend were used to obtained some results, as follows: ¬vegetation coverage had obvious characteristics with periodic change in research area for 26 years, and vegetation growth peak appeared on August, while the lowest appeared on January. The extreme values in Ordos City were 0.2351 and 0.1176, while they were 0.2657 and 0.1272 in ShenDong coalfield. The NDVI value fluctuation was a modest rise trend overall in research area. The extreme values were 0.3071 and 0.1861 in Ordos City, while they were 0.3454 and 0.1904 in ShenDong coalfield. In spatial distribution, slight improvement area and slight degradation area were accounting for 42.49% and 8.37% in Ordos City, while slight improvement area moderate improvement area were accounting for 70.59% and 29.41% in ShenDong coalfield. Above of results indicated there was less vegetation coverage in research area, which reflected the characteristics of fragile natural geographical environment. In addition, vegetation coverage was with a modest rise on the whole, which reflected the natural environment change.

  17. 鄂尔多斯经济发展的SWOT分析%SWOT Analysis of Economic Development in Ordos



    最近几年里,鄂尔多斯市的经济发展十分迅速,本文就是对鄂尔多斯市经济发展的SWOT分析,SWOT即:优势(Strengths)、劣势(Weakness)、机会(Opportunities),威胁(Threats)的简称,并且给出了进行分析之后得出的启示.%In recent years, the Ordos economy develops very quickly. This paper makes the SWOT (Strengths, Weakness, Opportunities, Threats)analysis of the economic development of the Ordos City, and gives the inspiration through analysis.

  18. SOLUS, SOLA: Constructing a Christocentric faith model of the �ordo salutis�

    Andre van Oudtshoorn


    Full Text Available This article develops a non-linear model of the ordo salutis with Christ at the centre. It shows that each individual event is a manifestation of what Christ has done and a call to faith in him. Faith is shown to comprise of consensus (agreement and fiducia (trust. Through this model, the creative tension between the objective (indicative and the subjective (imperative dimensions of the gospel as well as the tension between God�s eschatological time and our unfulfilled time are maintained in such a way that they both complement and limit each other. This tension, it is argued, is intrinsically linked to the way in which Christ continues to be present within our world as both Lord and Spirit. As Lord, Jesus is proclaimed as the One who has already overcome our broken reality; as the Spirit, Christ continues to be vulnerable to be resisted and rejected by us. As the Spirit of the risen Lord, he is nevertheless able to perform miracles and overcome our broken reality as the gospel is proclaimed. A short analysis of the way in which the Bible refers to some of the events in the ordo salutis confirms the legitimacy of this model.Intradisciplinary and/or interdisciplinary implications: It is argued that this model overcomes many objections against the traditional understanding of the ordo salutis. By challenging the underlying presuppositions of both Arminiaism and Calvinism, this article provides a unique alternative which does justice to key insights from both traditions and adds a new voice to the ongoing debate between Arian, Pelagian and semi-pelagian theologians, on the one side, and Reformed theologians, on the other side. It thus makes a significant intradisciplinary contribution to systematic theology. It also aligns the universality of salvation in Christ as the second Adam to the continuing need for a personal faith response to Christ.

  19. Exploration Experience and Problem concerning Deep Basin Gas in the Ordos Basin



    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.

  20. Temporo-spatial Coordinates of Evolution of the Ordos Basin and Its Mineralization Responses

    LIU Chiyang; ZHAO Hongge; ZHAO Junfeng; WANG Jianqiang; ZHANG Dongdong; YANG Minghui


    The Ordos basin was developed from Mid-Late Triassic to Early Cretaceous, and then entered into its later reformation period since the Late Cretaceous. Its main body bears the features of an intra-cratonic basin. The basin also belongs to a multi-superposed basin which has overlapped on the large-scale basins of the Early and Late Paleozoic. Currently, Ordos basin has become a residual basin experienced reformation of various styles since the Late Cretaceous. It's suggested that there were at least four obvious stages of tectonic deformations existing during the basin's evolution, dividing the evolution and sedimentation into four stages. The prior two stages were of the most prosperous, during which the lake basin was broad, the deposition range was more than twice larger than the current residual basin, resulting in major oil- and coal-bearing strata. The two stages were separated by regional uplift fluctuations in the area. At the end of the Yan'an Stage, the depositional interruption and erosion were lasting for a short period of time. The third one is the Mid- Jurassic Zhiluo-Anding stage, in which the sedimentation extent was still broad but the lake area was obviously reduced. In the Late Jurassic tectonic deformation was intensive. A thrust-nappe belt was formed on the basin's western margin while conglomerate of different thickness were accumulated within the foredeep of the eastern side. The central and eastern parts of the basin were subject to erosion and reformation. A regional framework with "uplift in the east and depression in the west" took shape in the area west of the Yellow River. In the Early Cretaceous sediments were widely distributed, unconformably overlapping the former western margin thrust belt and the ridges on the northern and southern borders. There are abundant energy resources such as oil, natural gas, coal and uranium deposits formed in Ordos Basin. The main stages of generation, mineralization and positioning of the multiple energy

  1. Tectonic history of the Ordos Block and Qinling Orogen inferred from crustal thickness

    Feng, Mei; An, Meijian; Dong, Shuwen


    The Ordos Block and the Qinling Orogen in central China are key regions that have been affected by Indo-Eurasian collision, convergence of the North China, South China and Siberian cratons, and subduction of the Pacific oceanic plate during the Phanerozoic. Investigation of the crustal structure in this area can therefore provide significant insights into the interactions among these tectonic blocks and plates. The Chinese Academy of Geological Sciences deployed ca. 249 portable broad-band seismic stations in this area from 2011 to 2016, and we retrieved P-wave receiver functions (RFs) from these new stations, and also from all other available permanent and portable seismic stations in China. Crustal thicknesses beneath the stations were retrieved using 1-D S-wave velocity models, which were obtained by linearized inversion of the RFs with initial reference models from regionalized S-wave velocities of surface wave inversions. We demonstrate with synthetic tests that this inversion scheme is superior to a jointly linearized inversion of RFs and surface waves. The results show that crustal thicknesses generally correlate with tectonic domains in the study region. Thus, thick crust is present beneath the Daba Shan region and the area close to the northeastern Tibetan Plateau, intermediate-thickness crust is present beneath the Ordos Block and the central North China Craton, and thin crust exists beneath the North China Plain. However, some notable exceptions exist. The crust beneath the central Qinling is thinner than that beneath the neighbouring Daba Shan region and even the Weihe Basin, implying that subduction and collision of the North China and South China cratons in the Palaeozoic did not produce a thick crust beneath the suture. The relatively thin crust beneath the eastern and central Qinling must be denser than that beneath neighbouring areas. All the basins around the Ordos Block have been considered to be graben. However, our results show that the crust

  2. Quantitative Assessment of Desertification Using Landsat Data on a Regional Scale – A Case Study in the Ordos Plateau, China

    Jianjun Pan


    Full Text Available Desertification is a serious threat to the ecological environment and social economy in our world and there is a pressing need to develop a reasonable and reproducible method to assess it at different scales. In this paper, the Ordos Plateau in China was selected as the research region and a quantitative method for desertification assessment was developed by using Landsat MSS and TM/ETM+ data on a regional scale. In this method, NDVI, MSDI and land surface albedo were selected as assessment indicators of desertification to represent land surface conditions from vegetation biomass, landscape pattern and micrometeorology. Based on considering the effects of vegetation type and time of images acquired on assessment indictors, assessing rule sets were built and a decision tree approach was used to assess desertification of Ordos Plateau in 1980, 1990 and 2000. The average overall accuracy of three periods was higher than 90%. The results showed that although some local places of Ordos Plateau experienced an expanding trend of desertification, the trend of desertification of Ordos Plateau was an overall decrease in from 1980 to 2000. By analyzing the causes of desertification processes, it was found that climate change could benefit for the reversion of desertification from 1980 to 1990 at a regional scale and human activities might explain the expansion of desertification in this period; however human conservation activities were the main driving factor that induced the reversion of desertification from 1990 to 2000.

  3. Origin and Superposition Metallogenic Model of the Sandstone-type Uranium Deposit in the Northeastern Ordos Basin, China

    LI Ziying; CHEN Anping; FANG Xiheng; OU Guangxi; XIA Yuliang; SUN Ye


    This paper deals with the metallogenic model of the sandstone type uranium deposit in thenortheastern Ordos Basin from aspects of uranium source, migration and deposition. A superpositionmetallogenie model has been established due to complex uranium mineralization processes withsuperposition of oil-gas reduction and thermal reformation.

  4. Moho fabrics of North Qinling Belt, Weihe Graben and Ordos Block in China constrained from large dynamite shots

    Li, Hongqiang; Gao, Rui; Xiong, Xiaosong; Wang, Haiyan; Li, Wenhui


    The Qinling Orogen Belt (QOB), Weihe Graben (WG) and the southern margin of the Ordos Block (SOB), lying on the central portion of China, had been involved into the amalgamation of China (Asian continent) through subduction, collision to exhumation processes. The Moho fabrics beneath this region, recorded part of the evolution. Therefore, its thickness and internal structure may provide significant knowledge and contribute to the understanding the intracontinental deformation of central China. In this paper, in order to place constrain on the nature beneath the study area, nine large dynamite shots (the charge ≥500 kg) used to infer the internal structure and characteristics of the crustal boundary. We analyse the specific characteristics of the Moho reflection, the amplitude decay curves in near vertical zone and generate a single-fold profile; in addition, it also address the internal structure and discuss its implication. The Moho is approximately at the depth of 39 km beneath the North Qinling Orogen (NQB) and the WG, and at the depth of 42 km beneath the SOB. The Moho shows a subtle uplift and the crust is thin under the NQB. The north-dipping reflectors between the lower crust and the uppermost mantle extend to the middle of the WG, and the south-dipping reflectors in the lower crust of the NQB are truncated by the Moho, therefore both of features and structures exhibit a `Crocodile' like structure and are most probably the remnants of the amalgamation of the NQB and the NCB. The transparent reflection Moho beneath the southern part of the WG may indicate the existence of a magma channel. The Weihe Fault is interpreted as a shallow, near-surface feature resulted from the upwelling magma; SOB represents a relatively weak region and could accommodate the crustal shortening during the formation of the China continent in Triassic.

  5. Upper Paleozoic coal measures and unconventional natural gas systems of the Ordos Basin, China

    Xuan Tang


    Full Text Available Upper Paleozoic coal measures in the Ordos Basin consist of dark mudstone and coal beds and are important source rocks for gas generation. Gas accumulations include coal-bed methane (CBM, tight gas and conventional gas in different structural areas. CBM accumulations are mainly distributed in the marginal area of the Ordos Basin, and are estimated at 3.5 × 1012 m3. Tight gas accumulations exist in the middle part of the Yishan Slope area, previously regarded as the basin-centered gas system and now considered as stratigraphic lithologic gas reservoirs. This paper reviews the characteristics of tight gas accumulations: poor physical properties (porosity < 8%, permeability < 0.85 × 10−3 μm2, abnormal pressure and the absence of well-defined gas water contacts. CBM is a self-generation and self-reservoir, while gas derived from coal measures migrates only for a short distance to accumulate in a tight reservoir and is termed near-generation and near-reservoir. Both CBM and tight gas systems require source rocks with a strong gas generation ability that extends together over wide area. However, the producing area of the two systems may be significantly different.

  6. Assessing the relative role of climate change and human activities in sandy desertification of Ordos region,China

    XU DuanYang; KANG XiangWu; LIU ZhiLi; ZHUANG DaFang; PAN JianJun


    Climate change and human activities are driving forces of sandy desertification and the relative role of them in sandy desertification is the hot point in related researches.A study was carried to assess the relative role of climate change and human activities in sandy desertification of Ordos region in China.Potential NPP and the difference between potential and actual NPP were selected as indicators to as-sess the relative role of climate change and human activities in sandy desertification,respectively.Assessing methods were built based on some scenarios for the reversion and expansion of sandy desertification and the relative role of climate change and human activities in sandy desertification of Ordos region were assessed from 1981 to 2000.The results showed that although some local places experienced an expansion of sandy desertification,the change of sandy desertification of Ordos region from 1981 to 2000 showed a stably reversing trend.The relative role of climate change and human ac-tivities in sandy desertification of Ordos region varied at different temporal and spatial scales in the reversion and expansion processes.In the reversion of sandy desertification,climate change was the dominant factor in the period of 1981 to 1990 and the reversed areas mainly induced by climate change including Mu Us sandy land and the transition zone between temperate steppe and temperate decidu-ous scrubs in north east of Ordos region; however,human activities controlled the reversed process during the period from 1991 to 2000 and the areas mainly induced by human activities distributed in all banners of Ordos region.In the expansion of sandy desertificallon,human activities were the dominant factor in the period of 1981 to 1990 and the expanded areas mainly included the regions around com-mon boundary of Hanggin,Dalad Banners and Dongsheng City; however,climate change dominated the expansion of sandy desertification from 1991 to 2000,the expanded areas equably distributed

  7. Sedimentary microfacies of the eighth member of the lower Shihezi Formation in northern Sulige Gas Field, Ordos Basin%苏里格气田北部下石盒子组盒8段沉积微相研究

    陈兆荣; 侯明才; 董桂玉; 谭万仓


    通过对苏里格气田北部20余口钻井岩心的岩石学特征、沉积构造、剖面结构的详细研究,结合测井相标志和古生物标志,认为苏里格气田北部盒8段属辫状河沉积,发育河道和洪泛平原两个亚相.河道亚相可进一步划分为河床底部滞留沉积和心滩两个微相,往往组成向上变细的剖面结构,测井曲线一般为中-高幅的齿化或微齿化的箱形或钟形;洪泛平原亚相在剖面结构上表现为砂泥岩的不等厚互层,测井曲线多呈锯齿状.在微相分析的基础上,编制了盒8上和盒8下两个时期的沉积微相平面图,其显示出河道心滩砂体呈南北向展布的规律.根据沉积相的时空展布规律,建立了本区盒8段的沉积相模式.%The eighth member of the Shihezi Formation consists of braided stream deposits including the channel and flooding plain subfacies on the basis of petrography, palaeontology, sedimentary structures, sectional architectures and well logs of more than twenty wells in northern Sulige Gas Field. The channel subfacies may be subdivided into two sedimentary microfacies: river-bed lag deposits and channel bar. These sedimentary microfacies generally display fining-upward depositional sequences, and moderate- to high-amplitude box-shaped or bell-shaped well logs. The flood plain subfacies comprises the alternating beds of sandstone and mudstone, and exhibits zigzag well logs. The sedimentary microfacies analysis has led to the construction of the sedimentary facies plans and model for the eighth member of the Shihezi Formation.

  8. A Reforma do Ordo Missae no Vaticano II: aspectos históricos teológicos e pastorais (The Reform of the Ordo Missae Vatican II: historical aspects theological and pastoral

    Vanderson de Sousa Silva


    Full Text Available No presente artigo tratar-se-á da reforma do Ordo Missae perpetrado pelo Concílio Ecumênico Vaticano II (1962-1965, em seus aspectos históricos e teológicos, bem como as incidências pastorais da mesma. Buscar-se-á como delimitação somente analisar a reforma do Ordo Missae, no que tange as Orações Eucarísticas implementadas pela reforma conciliar, especialmente ao problema da ‘reforma’ do Ordo Missae, do Cânon Romano e das novas Orações Eucarísticas. Em suma, vislumbra-se a reforma litúrgica, os aspectos teológicos da Sacrosanctum Concilio e o ‘problema do Cânon’. O Concílio optou por retornar às fontes, redescobriu as Anáforas Eucarísticas Ocidentais e Orientais e adaptou-as nas Novas Orações Eucarísticas: a Anáfora de Hipólito de Roma em sua obra Traditio Apostolica que foi adaptada para ser a Oração Eucarística II; a Oração Eucarística III é inspirada na liturgia galicana e moçarábica; a Oração Eucarística IV de inspiração na Anáfora de Basílio e no Brasil somente, a Oração Eucarística V. Palavras-chave: Ordo Missae. Concílio Vaticano II. Orações Eucarísticas.  Abstract: The Reform Ordo Missae Vatican II: historical, ,theological and pastoral aspects. This article deals with the reform of the Ordo Missae held by the Second Vatican Council (1962-1965, in their historical and theological aspects, as well as its pastoral implications. The text will analyze the reform of Ordo Missae regarding the Eucharistic Prayers implemented by the Conciliar reform, especially the problem of 'reform' of the Ordo Missae, the Roman Canon and new Eucharistic Prayers. In short, this analysis aims to liturgical reform, the theological aspects of Sacrosanctum council and the 'problem of the canon'. The council opted to return to the sources, rediscovered the Eucharistic Anaphoras and adapted them in New Eucharistic Prayers: the Anaphora of Hippolytus of Rome in his Traditio Apostilica which was adapted for

  9. Type of diagenesis and its controlling effect on oil and gas reservoirs in the Xiashihezi Formation in Linxing district, Ordos Basin%鄂尔多斯盆地临兴地区下石盒子组成岩作用类型及其对油气储层的控制作用

    谢英刚; 叶建平; 潘新志; 段长江; 陈庆; 杨丽萍; 喻玉洁


    本文通过大量岩石薄片、扫描电镜及阴极发光等的观察,分析了临兴地区下石盒子组成岩作用类型、成岩作用对物性的影响以及与油气分布规律的关系。结果表明,研究区下石盒子组成岩作用主要包括压实作用以及胶结弱溶蚀;而且压实作用大大降低了原生孔隙体积,胶结作用堵塞了孔隙和喉道,溶蚀作用提高了砂岩的储集性能。成岩作用在砂体不同部位的差异是形成岩性圈闭的条件,纵向上水下分流河道、河口坝底部和顶部为低渗储层,中部位为渗透层,因此水下分流河道和河口坝砂体可成为一套岩性圈闭;在平面上原生孔+次生孔相和次生孔相分布于水下分流河道和河口坝等分选较好,粒度较粗的微相中。分选较差、粒度较细的远砂坝和席状砂微相发育的砂岩杂基含量较高,主要为低渗砂岩,为油气富集区形成横向遮挡条件。总体上来说,沉积相为水下分流河道和河口坝微相,成岩相为原生孔+次生孔相以及次生孔相为有利的储层,是油气的最为有利聚集场所,其次为远砂坝和席状砂微相,成岩相为自生高岭石充填粒间孔相和胶结弱溶蚀相的储层,含气性相对较差。%The authors analyze the influence of diagenesis and diagenesis types on physical properties , and relationships between diagenesis and distribution pattern of oil and gas in the Xiashihezi Formation in Linxing area though observing lots of rock slice ,scanning electron microscope and cathodoluminescence . Diagenesis types include compaction ,cementation and weak dissolution ;Compaction greatly destroys primary pore volume ,cementation blocks pores and throats ,dissolution improves the reservoir quality of the sandstones in the Xiashihezi formation .The condition of forming lithologic trap are the diagenesis differences in different part of the sand ,in the vertical of which ,the bottom

  10. An investigation of Water-gas interface migration of the upper Paleozoic gas pool of the Ordos Basin using reservoir fluid inclusion information

    MI Jingkui; XIAO Xianming; LIU Dehan; LI Xianqing; SHEN Jiagui


    There is a particular characteristic in the for-mation of the Upper Paleozoic gas pool in the Ordos Basin that is its water-gas interface migrated regional during geological history.However,there has been lack of detailed research on this paper,the formation time of hte fluid inclusions formed in the water-gas transition zone of the gas pool was deduced using their trapping temperatures and combining of the burial with geothermal history of the basin.On the basis of this,the isochrone of water-gas interface migration for the gas pool was mapped .The result shows that the gas pool began to form around the yanan Area at about 165Ma,and then developed and enlarged toward the north direction.The gas pool finally formed at about 129 Ma.Since the basin uplifted from the late Cretaceous and gas supply decreased,the water-gas interface of the gas pool migratec back to the present position.

  11. Present Situation and Exploration Potentialities of Natural Gas Resources in Ordos Basin


    @@ Ordos Basin is the second largest sedimentary basin in China, with an area of 370 thousand km2. Since the first onshore oil well was drilled successfully in northern Shaanxi of China, there has been a century of oil and gas exploration in the basin, and it may be said that the oil exploration has a long history, but for natural gas exploration, it still may be regarded as a new area, because large-scale research, exploration, and development of natural gas in the basin have relatively lagged. The four big gas fields of Jingbian, Sulige, Yulin, and Uxin Banner with respective reserves of more than one hundred giga cubic meters were discovered since 1990s[1]. Therefore,the basin has a great resources potential of natural gas and a low discovery ratio of gas reserves. The natural gas industry has broad prospects of development.

  12. Coexistence and inherence of diverse energy resources in the Ordos Basin, China

    CHANG Xiangchun; WANG Mingzhen; HAN Zuozhen


    The Ordos Basin is abundant in oil, natural gas, coal, coalbed gas and sandstone-type uranium deposits. Oil pools are hosted mainly in the Triassic and Jurassic systems in the southern part of the basin. Gas reservoirs which occur dominantly in the northern part of the basin are situated vertically beneath the oil pools. Coal measures are widely distributed in the Carboniferous, Permian, Jurassic and Triassic systems. Developed at the margin of the basin are the sandstone-type uranium deposits and coalbed gas. The investigations of sources and timing of various energy resources indicated that there are certain genetic connections among them. Especially the contributions of coal measures to natural gas, the supplement of coalbed gas to deep basin gas and the reduction of uranium deposits by natural gas are relatively remarkable.

  13. REE/trace element characteristics of sandstone-type uranium deposits in the Ordos Basin

    LING Mingxing; YANG Xiaoyong; SUN Wei; MIAO Jianyu; LIU Chiyang


    The major elements, trace elements and REEs were analyzed on the samples collected from the sandstone-type uranium deposits in the Ordos Basin to constrain the mechanism of uranium enrichment. The total REE amount ranges from 36.7 to 701.8 μg/g and the REE distribution patterns of the sandstone-type uranium samples are characterized by LREE enrichment and high REE depletion. The results also indicated a high Y abundance and Eu anomalies between 0.77-1.81. High-precision ICP-MS results showed that U abundances are within the range of 0.73-150 μg/g, showing some strong correlation between U enrichment and related elements such as Ti, V, Zr, Mo, and Au. In addition, Th abundance is correlated with ΣREE.

  14. Characteristics of bleaching of sandstone in northeast of Ordos Basin and its relationship with natural gas leakage

    MA; YanPing; LIU; ChiYang; ZHAO; JunFeng; HUANG; Lei; YU; Lin; WANG; JianQiang


    Bleaching of sandstone has significant applications to tracing hydrocarbon pathways and evaluating the scale of natural gas seepage. Bleaching of sandstones in the northeast of Ordos Basin is mainly distributed in the Mesozoic Yan'an Formation. Studying on petrology, major elements, REEs and trace elements of bleached sandstones and comparing with adjacent sandstones, combining with geologic-geochemical evidences of gas seepage in the northeast of the basin, the bleached sandstones are formed in the acid environment and reducing fluids. Characteristics of petrology show that the contents of kaolinite are high and the color of margin of ferric oxide minerals is lighter than that of the center. Major elements of sandstone samples show high contents of Al2O3 and low ratio of Fe3+/Fe2+. The TFe2O3 content of the bleached sandstone is lower than that of red rock. REE data show that bleached sandstones have low ∑REE contents and Eu-depleted and slightly Ce-enriched. Trace elements show that the bleached sandstones enrich in Co, deplete in Sr, and slightly enrich in Zr and Hf which are close to the values for the green alteration sandstones, and slightly lower than ore-bearing sandstones. Geochemical characteristics of oil-bearing sandstone in the northern basin suggest that the oil-shows are formed by matured Carboniferous-Permian coal bed methane escaping to the surface, and natural gas in field could migrate to the north margin of the basin. The δ13C (PDB) andδ18O(PDB) values of calcite cement in the study area range from -11.729‰ to -10.210‰ and -14.104‰ to -12.481‰, respectively. Theδ13C (PDB) values less than -10‰ imply the carbon sources part from organic carbon. Comprehensive study suggests that the gas leakage has occurred in the northeastern basin, which is responsible for bleaching of the sandstone on top of the Yan'an Formation.

  15. A gravity study along a profile across the Sichuan Basin, the Qinling Mountains and the Ordos Basin (central China): Density, isostasy and dynamics

    Zhang, Yongqian; Teng, Jiwen; Wang, Qianshen; Lü, Qingtian; Si, Xiang; Xu, Tao; Badal, José; Yan, Jiayong; Hao, Zhaobing


    In order to investigate the structure of the crust beneath the Middle Qinling Mountains (MQL) and neighboring areas in the North China Block and South China Block, a north-south gravity profile from Yuquan in the Sichuan Basin to Yulin in the Ordos Basin was conducted in 2011. The Bouguer gravity anomaly is determined from a high-quality gravity dataset collected between 31°N and 36°N of latitude, and varies between -200 and -110 mGal in the study region. Using accredited velocity density relationships, an initial crust-mantle density model is constructed for MQL and adjacent areas, which is later refined interactively to simulate the observed gravity anomaly. The present study reveals the features of the density and Bouguer gravity with respect to the tectonic units sampled by the profile. The lithosphere density model shows typical density values that depict a layered structure and allow differentiate the blocks that extend along the reference profile. The gravity field calculated by forward modeling from the final density distribution model correlates well with the measured gravity field within a standard deviation of 1.26 mGal. The density in the crystalline crust increases with depth from 2.65 g/cm3 up to the highest value of 2.95 g/cm3 near the bottom of the crust. The Conrad interface is identified as a density jump of about 0.05 g/cm3. The average density of the crust in MQL is clearly lower than the density in the formations on both sides. Starting from a combined Airy-Pratt isostatic compensation model, a partly compensated crust is found below MQL, suggesting future growth of the crust, unlike the Ordos and Sichuan basins that will remain stable. On the basis of the density and isostatic state of the crust and additional seismological research, such as the P-wave velocity model and Poisson's ratio, it is concluded that the lower crust delamination is a reasonable interpretation for the geophysical characteristics below the Qinling Orogen.

  16. 纳米乳化石蜡钻井液在延长低渗油田的应用%Application of Nano-wax emulsion environmental protection drilling fluid in YanChang low permeability oilfield

    李红梅; 李伟; 于小龙; 赵毅; 武骞; 何仲


    石蜡纳米乳液与延长低渗油藏常用聚合物钻井液体系有良好的配伍性,可改善体系的流变性,降低滤失量,具有明显的润滑效果和抑制粘土水化膨胀与分散的能力,对岩心损害程度低,油层保护效果好。石蜡纳米乳液在延长油田成功进行了5口井现场试验,结果证明,加入石蜡纳米乳液后,井壁无坍塌,起下钻畅通,完井电测及下套管作业顺利,钻井时效提高,油气产量高,环保效果好。石蜡纳米乳液钻井液适用于延长油田定向井的钻井施工,可在延长油田推广使用。%Nano-wax emulsion has good compatibility with polymer drilling fluid used in YanChang low permeability reservoir. It could improve the rheological characteristic, and reduce the filtration loss. It has obvious lubricating effect and clay hydration and dispersion inhibition ability. It could reduce the core damage and protect the reservoir. Nano-wax emulsion has been successfully applied in 5 wells in Yanchang oilfield. Results showed that, adding nano-wax emulsion, wellhore was stable, tripping was unblocked, electrical measurement and casing worked smoothly, oil production improved, and environmental was protected. Nano-wax emulsion was suitable for YanChang oil field directional wells, and the application should be spread.

  17. The distribution rule and seepage effect of the fractures in the ultra-low permeability sandstone reservoir in east Gansu Province,Ordos Basin


    To study the impact of the fractures on development in the ultra-low permeability sandstone reservoir of the Yangchang Formation of the Upper Triassic in the Ordos Basin,data on outcrops,cores,slices,well logging and experiments are utilized to analyze the cause of the formation of the fractures,their distribution rules and the control factors and discuss the seepage flow effect of the fractures. In the studied area developed chiefly high-angle tectonic fractures and horizontal bedding fractures,inter-granular fractures and grain boundary fractures as well. Grain boundary fractures and intragranular fractures serve as vital channels linking intragranular pores and intergranular solution pores in the reservoir matrix,thus providing a good connectivity between the pores in the ultra-low perme-ability sandstone reservoir. The formation of fractures and their distribution are influenced by such external and internal factors as the palaeo-tectonic stress field,the reservoir lithological character,the thickness of the rock layer and the anisotropy of a layer. The present-day stress field influences the preservative state of fractures and their seepage flow effect. Under the tec-tonic effect of both the Yanshan and Himalayan periods,in this region four sets of fractures are distributed,respectively assuming the NE-SW,NW-SE,nearly E-W and nearly S-N orientations,but,due to the effect of the rock anisotropy of the rock formation,in some part of it two groups of nearly orthogonal fractures are chiefly distributed. Under the effect of the present-day stress field,the fractures that assume the NE-SW direction have a good connectivity,big apertures,a high permeability and a minimum starting pressure,all of which are main advantages of the seepage fractures in this region. With the development of oilfields,the permeability of the fractures of dif-ferent directions will have a dynamic change.

  18. Study on Shear Wave Velocity Structure and Velocity Ratio Beneath Ordos Block and Its Eastern and Southern Margins

    Zhang Xuemin; Diao Guiling; Shu Peiyi


    Using pure S wave fitting method, we studied the shear wave velocity structures under the Ordos block and its eastern and southern marginal areas. The results show that the velocity structure beneath Yulin station in the interior of Ordos block is relatively stable, where no apparent change between high and low velocity layers exists and the shear wave velocity increases steadily with the depth. There is a 12km thick layer at the depth of 25km under this station, with an S wave velocity ( Vs = 3.90km/s) lower than that at the same depth in its eastern and southern areas (Vs ≥ 4.00km/s). The crust under the eastern margin of Ordos block is thicker than that of the Yulin station, and the velocity structures alternate between the high and Iow velocity layers, with more low velocity layers. It has the same characteristic as having a 10km-thick low velocity layer ( Vs = 3.80km/s) in the lower crust but buried at a depth of about 35km. Moreover, we studied the Vi/Vs ratio under each station in combination with the result of P wave velocity inversion. The results show that, the average velocity ratio of the Yulin station at the interior of Ordos block is only 1.68, with a very low ratio (about 1.60)in the upper crust and a stable ratio of about 1.73 in the mid and lower crust, which indicates the media under this station is homogenous and stable, being in a state of rigidity. But at the stations in the eastern and southern margins of the Ordos block, several layers of high velocity ratio (about 1.80) have been found, in which the average velocity ratio under Kelan and Lishi stations at the eastern margin is systemically higher than that of the general elastical body waves (1.732). This reflects that the crust under the marginal areas is more active relatively,and other materials may exist in these layers. Finally, we discussed the relationship among earthquakes, velocity structures beneath stations and faults.

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

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


    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.

  20. Treatment of Sulphur-containing Produced Water for Re-injection in Yanchang Oilfield%延长油田含硫采出水回注水质处理研究

    叶政钦; 崔明月; 蒋卫东; 赫安乐


    Oily sewage from Qilicun block of Yanchang Oilfield contains large amounts of S2-、SO4 2-、HCO3 -and SRB. The laboratory static corrosion coupon experiments and the XRD analysis results of the scale samples from the corroded water injection pipeline show that the corrosion of the water injection pipeline is mainly local corrosion caused by high sulfur content. Corrosion inhibitor Xasy-201 and bactericides FW-BT01 and FW-BT02 are screened through strict experiments to reduce the corrosion rate of the oily sewage. The oily sewage is purified using physical and chemical method. The pH value of sewage,iron removal agent,inorganic flocculantand and or-ganic flocculant are optimized,and the results show that when the pH value of the oily sewage is adjusted to 7. 5,the mass concentration of iron removal agent RF-2,inorganic flocculantand PAC and organic flocculant PAM(12 million)is 25mg/L,30 mg/L and 1. 0 mg/L separately,the mass concentration of the suspended matter in the treated sewage is less than 10 mg/L,the sulfur content of the treated oily sewage obviously decreases,and its corrosion rate is less than 0. 007 6 mm/a. The treated water can reach to the standard for re-in-jection water,and it is of good compatibility with formation water.%延长油田七里村区块采油污水富含S2-、SO42-、HCO3-、SRB。室内静态腐蚀挂片实验及注水管线腐蚀垢样XRD分析可知,管线腐蚀主要是局部腐蚀,引起腐蚀的主要原因是采出水中高含硫。通过实验筛选出效果较佳的缓蚀剂Xasy-201及杀菌剂FW-BT01、FW-BT02以降低腐蚀速率。采用物理化学法对采出水进行净化处理,优选了污水pH值、除铁剂、无机絮凝剂和有机絮凝剂。结果表明:当调节污水pH值为7.5、铁调剂RF-2质量浓度为25 mg/L,无机絮凝剂PAC质量浓度为30 mg/L、有机絮凝剂PAM(1200万)质量浓度为1.0 mg/L时,水中悬浮物质量浓度小于10 mg/L,硫含量明显降低,处理后污

  1. Mountain building at northeastern boundary of Tibetan Plateau and craton reworking at Ordos block from joint inversion of ambient noise tomography and receiver functions

    Guo, Zhen; Chen, Yongshun John


    We have obtained a high resolution 3-D crustal and uppermost mantle velocity model of the Ordos block and its surrounding areas by joint inversion of ambient noise tomography and receiver functions using seismic recordings from 320 stations. The resulting model shows wide-spread low velocity zone (Vs ≤ 3.4 km/s) in the mid-to-lower crust beneath northeastern Tibet Plateau, which may favor crustal ductile flow within the plateau. However, our model argues against the eastward crustal ductile flow beneath the Qinling belt from the Tibetan Plateau. We find high velocities in the middle part of Qinling belt which separate the low velocities in the mid-to-lower crust of the eastern Qinling belt from the low velocity zone in eastern Tibetan Plateau. More importantly, we observe significant low velocities and thickened lower crust at the Liupanshan thrust belt as the evidence for strong crustal shortening at this boundary between the northeastern Tibetan Plateau and Ordos block. The most important finding of our model is the upper mantle low velocity anomalies surrounding the Ordos block, particularly the one beneath the Trans North China Craton (TNCO) that is penetrating into the southern margin of the Ordos block for ∼100 km horizontally in the depth range of ∼70 km and at least 100 km. We propose an on-going lithospheric mantle reworking at the southernmost boundary of the Ordos block due to complicated mantle flow surrounding the Ordos block, that is, the eastward asthenospheric flow from the Tibet Plateau proposed by recent SKS study and mantle upwelling beneath the TNCO from mantle transition zone induced by the stagnant slabs of the subducted Pacific plate.

  2. Discussion on rotational tectonic stress field and the genesis of circum-Ordos landmass fault system



    When the resultant of applied forces does not pass through the center of an active landmass, the landmass will rotate, giving rise to a rotational tectonic stress field. The motion of a fault along the principal stress plane is determined by the mechanic features of the plane. Tensile fractures occur on the faults in the direction of the principal extensional stress plane, and fault-depression basins will be formed under a long-term action. Thrusting and overthrusting occur on faults in the direction of the principal compressional stress plane, or folds may be formed as a result. Information on geology shows that the North China landmass, which remained stable and intact for a long time, became disjointed in the Eogene period. In the course of disjunction, anticlockwise rotation took place in the Shanxi-Hebei-Shaanxi (Jin-Ji-Shan) landmass, giving rise to the fault-depression system in its periphery. In the Pliocene epoch the landmass lost stability and its eastern boundary moved westward. As a result, the Shanxi graben system appeared and Ordos landmass was formed. Structural and mechanic features of the main faults around Jin-Ji-Shan landmass can be explained with principal stress plane of a rotational tectonic stress field.

  3. Genetic Relationship between Natural Gas Dispersal Zone and Uranium Accumulation in the Northern Ordos Basin, China

    GAN Huajun; XIAO Xianming; LU Yongchao; JIN Yongbin; TIAN Hui; LIU Dehan


    The Ordos Basin is well-known for the coexistence of oil, natural gas, coal and uranium. However, there has been little research to discuss the genetic relationship between them. In this paper, a case study of the Zaohuohao area in Dongsheng, Inner Mongolia, China, is conducted to investigate the genetic relationship between the natural gas and the uranium accumulation. Fluid inclusion data from the uranium-bearing sandstone samples indicate that the fluid inclusions formed in a gas-water transition zone. Using the homogeneous temperatures of aqueous inclusions coeval with hydrocarbonbearing inclusions, combined with the buried history and paleo-temperature data, the gas-water transition zone reached the area at about 110 Ma. On the basis of this, the contents of Uranium (U)and Total Organic Carbon (TOC) of the samples were analyzed, and there was no obvious relation between them. With regard to the available data from both publications and this study, it is found that the U mineralization has a spatiotemporal accordance with the gas-water dispersal zone. Thus, it is believed that the natural gas in the gas-water zone is an effective reducer to the U-bearing ground water abundant in oxygen, which is the main factor to U accumulation. This result can be used as the reference to the U mines predicting and prospecting.

  4. Académico Doctor Julio Hernando Ordoñez Garay (1910-2008.

    Jaime Gómez-González


    Condecorado con el “Premio a una Vida” por la Sociedad de Cardiología, en calidad de Precursor de la Cardiología en Colombia. Miembro del Comité de redacción del Acta Physiologica Latinoamericana, Buenos Aires (1971, Miembro del Consejo Asesor del Fondo Colombiano de Investigaciones Científicas (Colciencias (1970, Medalla de la Facultad de Medicina de la Universidad Javeriana, Comendador, Medico, Fundador y Profesor. Premio Alejandro Angel Escobar, Mención Honorífica (1957. Organizador y primer presidente del Congreso Colombiano de Cardiología, (Bogota 1956. Profesor visitante de la Unesco al Simposio sobre Biología de la Altura (Lima 1949, Fundador y Director de los Anales de Biología (Bogota, Miembro del Comité de Redacción de la Revista British Abstracts (Londres. Citado por Jalbosky S, en el libro Ilustrated Dictionary of Eponyms, por una nueva entidad nosológica que denomina “Ordoñez Melanosis” (Saunders Co, 1969;229.

  5. Land Degradation Monitoring in the Ordos Plateau of China Using an Expert Knowledge and BP-ANN-Based Approach

    Yaojie Yue


    Full Text Available Land degradation monitoring is of vital importance to provide scientific information for promoting sustainable land utilization. This paper presents an expert knowledge and BP-ANN-based approach to detect and monitor land degradation in an effort to overcome the deficiencies of image classification and vegetation index-based approaches. The proposed approach consists of three generic steps: (1 extraction of knowledge on the relationship between land degradation degree and predisposing factors, which are NDVI and albedo, from domain experts; (2 establishment of a land degradation detecting model based on the BP-ANN algorithm; and (3 land degradation dynamic analysis. A comprehensive analysis was conducted on the development of land degradation in the Ordos Plateau of China in 1990, 2000 and 2010. The results indicate that the proposed approach is reliable for monitoring land degradation, with an overall accuracy of 91.2%. From 1990–2010, a reverse trend of land degradation is observed in Ordos Plateau. Regions with relatively high land degradation dynamic were mostly located in the northeast of Ordos Plateau. Additionally, most of the regions have transferred from a hot spot of land degradation to a less changed area. It is suggested that land utilization optimization plays a key role for effective land degradation control. However, it should be highlighted that the goals of such strategies should aim at the main negative factors causing land degradation, and the land use type and its quantity must meet the demand of population and be reconciled with natural conditions. Results from this case study suggest that the expert knowledge and BP-ANN-based approach is effective in mapping land degradation.

  6. Brittle Deformation in the Ordos Basin in response to the Mesozoic destruction of the North China Craton

    Wang, Q.; Jiang, L.


    Craton is continental block that has been tectonically stable since at least Proterozoic. Some cratons, however, become unstable for some geodynamic reasons. The North China Craton (NCC) is an example. Structure geological, geochemical, and geophysical works have revealed that the NCC was destructed in Cretaceous and that lithosphere thickness beneath the eastern NCC were thinned by 120 km. The present study will focus on deformation of the western NCC, and to understand the effect of the Mesozoic destruction of the North China Craton (NCC). Structural partitioning of the Ordos Basin, which is located in the western NCC, from the eastern NCC occurred during the Mesozoic. Unlike the eastern NCC where many Cretaceous metamorphic core complexes developed, sedimentary cover of the NCC remains nearly horizontal and deformation is manifested by joint. We visited 216 sites of outcrops and got 1928 joints measurements, among which 270 from Jurassic sandstones, 1378 from the Upper Triassic sandstones, 124 from the Middle and Lower Triassic sandstones, and 156 from Paleozoic sandstones. In the interior of the Ordos Basin, joints developed quite well in the Triassic strata, while joints in the Jurassic stata developed weakly and no joint in the Cretaceous strata. The Mesozoic stratigraphic thickness are: 1000 meters for the Lower Triassic, the Middle Triassic sandstone with thickness of 800 meters, 3000 meters for the Upper Triassic, 4000 meters for the Jurassic, and 1100 meters for the Lower Cretaceous. The vertical difference in joint development might be related to the burying depth of the strata: the higher the strata, the smaller the lithostatic stress, and then the weaker the joint. Joints in all stratigraphic levels showed a similar strain direction with the sigma 1 (the maximum pressure stress) vertical and the sigma 3 (the minimum pressure stress) horizontal and running N-S. The unconformity below the Cretaceous further indicates that joints in Jurassic and Triassic

  7. Cretaceous desert cycles, wind direction and hydrologic cycle variations in Ordos Basin:Evidence for Cretaceous climatic unequability

    JIANG Xinsheng; PAN Zhongxi; XIE Yuan; LI Minghui


    Climatic state under greenhouse effect is a currently hot point. Whether greenhouse climate in geological history, especially in Cretaceous, was equable or not has aroused extensive discussion. By analysis on depositional cyclcity, wind direction change and hydrologic cycle variation of Cretaceous desert in the Ordos Basin of China, the unequability of Cretaceous climate is dealt. It is shown that Cretaceous climate was extremely cyclic, not only having long and mid term but also having strong seasonal even instantaneous changes. Therefore, it is suggested that Cretaceous climate was not equable.

  8. Cretaceous desert cycles, wind direction and hydrologic cycle variations in Ordos Basin: Evidence for Cretaceous climatic unequability

    JIANG; Xinsheng; PAN; Zhongxi; XIE; Yuan; LI; Minghui


    Climatic state under greenhouse effect is a currently hot point. Whether greenhouse climate in geological history, especially in Cretaceous, was equable or not has aroused extensive discussion. By analysis on depositional cyclcity, wind direction change and hydrologic cycle variation of Cretaceous desert in the Ordos Basin of China, the unequability of Cretaceous climate is dealt. It is shown that Cretaceous climate was extremely cyclic, not only having long and mid term but also having strong seasonal even instantaneous changes. Therefore, it is suggested that Cretaceous climate was not equable.

  9. Contemporary kinematics of the Ordos block, North China and its adjacent rift systems constrained by dense GPS observations

    Zhao, Bin; Zhang, Caihong; Wang, Dongzhen; Huang, Yong; Tan, Kai; Du, Ruilin; Liu, Jingnan


    The detailed kinematic pattern of the Ordos block, North China and its surrounding rift systems remains uncertain, mainly due to the low signal-to-noise ratio of the Global Positioning System (GPS) velocity data and the lack of GPS stations in this region. In this study, we have obtained a new and dense velocity field by processing GPS data primarily collected from the Crustal Motion Observation Network of China and from other GPS networks between 1998 and 2014. The GPS velocities within the Ordos block can be interpreted as counterclockwise rotation of the block about the Euler pole with respect to the Eurasia plate. Velocity profiles across the graben-bounding faults show relatively rapid right-lateral strike-slip motion along the Yinchuan graben, with a rate of 0.8-2.6 mm/a from north to south. In addition, a right-lateral slip rate of 1.1-1.6 mm/a is estimated along the central segment of the Shanxi rift. However, strike-slip motion is not detected along the northern and southern margins of the Ordos block. Conversely, significant extension motion is detected across the northwestern corner of the block, with a value of 1.6 mm/a, and along the northern segment of the Shanxi rift, where an extensional rate of 1.3-1.7 mm/a is measured. Both the Daihai and Datong basins are experiencing crustal extension. On the southwestern margin of the block, deformation across the compressional zone of the Liupanshan range is subtle; however, the far-field shorting rate is as high as 3.0 mm/a, implying that this region is experiencing ongoing compression. The results reveal that present-day fault slip occurs mainly along the block bounding faults, with the exception of faults along the northern and southern margins of the block. These results provide new insights into the nature of tectonic deformation around the Ordos block, and are useful for assessing the seismic activity in this region.

  10. Coal petrology and genesis of Jurassic coal in the Ordos Basin, China

    Weihua Ao


    Full Text Available Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin, northwestern China. The huge reserves of this high quality coal have a high commercial value. We studied the coal’s petrologic characteristics and its maceral distribution to determine the maceral’s contribution to generation of oil and gas. The results show that the Jurassic coals in the Ordos Basin have special petrological features because of the Basin’s unique depositional environment which was mainly a series of high-stand swamps in the upper fluvial system. These petrographic features are a result of the development of typical inland lakes where some sand bodies were formed by migrating rivers. After burial, the peat continued to undergo oxidizing conditions, this process generated extensive higher inertinite contents in the coals and the vitrinite components were altered to semi-vitrinite. The macroscopic petrographic types of these Jurassic coals are mainly semi-dull coal, dull coal, semilustrous and lustrous coal. The proportions of semi-dull coal and dull coal are higher in the basin margins, especially in the area near the northern margin. The numbers of semilustrous and lustrous coals increase southwards and towards the central basin. This situation indicates that different coal-forming swamp environments have major controlling effects on the coal components. Another observation is that in the Ordos’ coal sequences, especially in the lower part, some sandstone beds are thick, up to 20 m with a coarse grain size. The higher fusinite content in the macerals accompanies a higher semi-vitrinite content with more complete and regular plant cell structure. The fusinite structure is clear and well preserved. After burial, the lithology of the roof and floor rocks can continue to affect the evolution of coal petrology. The sand bodies in the roof and floor exhibit good

  11. 再论鄂尔多斯盆地寒武纪岩相古地理及沉积构造演化%Further Study on Lithofacies Palaeogeography and Sedimentary-Tectonic Evolution of Cambrian in Ordos Basin,North China

    陈启林; 白云来; 马玉虎; 刘晓光


    It is now a hot spot to prospect oil and gas in deep of Ordos basin,North China.Seven new lithofacies palaeogeography maps on Ordos have been sketched out,according to the guideline of which tectonism controls sedimentation,applying the sequence stratigraphy theory,on the ground of field outcrops observations,core observations,logging data and seismic profiles,applying the method of single factor analysis and comprehensive mapping,and taking tectonic-sediment evolution as storyline, and reservoir-accumulation as the goal.The research has shown that there was a dynamic evolution process in Cambrian in Ordos,in which carbonate ramps formed platforms and restricted platforms.The carbonate ramps were characterized by exchanging of clear water and muddy water.The research also shows that drought in early became relative humidity in late.There was a tectonic differentiation in south-north earlier and west-east later.Southern Ordos margin appeared aulacogen.Ancient Ordos Land (AOL)was,fundamentally,covered by seawater except the parts of north and west margin in the Middle-Late Cambrian.A conversion in which land was changed to sea had been completed.The characteristic of palaeogeography was mainly a shallow-water carbonate platform on the continental sea. The forming of “Ancient Ordos Sea”(AOS)was a turning point.The west arises in Late Cambrian, which is a rudiment of “Central Paleouplift”(CP)which mainly had formed in Ordovician.The Late Cambrian uplift ran in north to south and is basically the same range as “Ordovician Central Paleouplift”.Therefore,it has been proved that the earliest age of forming “Central Ordos Paleouplift”is from Cambrian Furongian to the Early Ordovician.It has also been proved that tidal flat is dominating facies in the Early Cambrian,oliticbeachs are distributed around the land in Zhangxia Formation in the Middle Cambrian and porous dolostones which distributed in whole areas mainly occur in the top of Cambrian

  12. Effects of hydrocarbon generation on fluid flow in the Ordos Basin and its relationship to uranium mineralization

    Chunji Xue


    Full Text Available The Ordos Basin of North China is not only an important uranium mineralization province, but also a major producer of oil, gas and coal in China. The genetic relationship between uranium mineralization and hydrocarbons has been recognized by a number of previous studies, but it has not been well understood in terms of the hydrodynamics of basin fluid flow. We have demonstrated in a previous study that the preferential localization of Cretaceous uranium mineralization in the upper part of the Ordos Jurassic section may have been related to the interface between an upward flowing, reducing fluid and a downward flowing, oxidizing fluid. This interface may have been controlled by the interplay between fluid overpressure related to disequilibrium sediment compaction and which drove the upward flow, and topographic relief, which drove the downward flow. In this study, we carried out numerical modeling for the contribution of oil and gas generation to the development of fluid overpressure, in addition to sediment compaction and heating. Our results indicate that when hydrocarbon generation is taken into account, fluid overpressure during the Cretaceous was more than doubled in comparison with the simulation when hydrocarbon generation was not considered. Furthermore, fluid overpressure dissipation at the end of sedimentation slowed down relative to the no-hydrocarbon generation case. These results suggest that hydrocarbon generation may have played an important role in uranium mineralization, not only in providing reducing agents required for the mineralization, but also in contributing to the driving force to maintain the upward flow.

  13. Discovery of effective scale source rocks of the Ordovician Majiagou Fm in the Ordos Basin and its geological significance

    Jianqi Tu


    Full Text Available There have been different views on the origins of gas reservoirs of Ordovician Majiagou Fm in the Ordos Basin, but none of them supports the opinion that there are scale source rocks (TOC>0.5% in the Majiagou Fm. In this paper, a series of analysis was made on cores and cutting samples taken from recent newly-drilled wells in the Ordovician reservoirs in the central–eastern areas of the Ordos Basin. Accordingly, the organic abundance features of different types of source rocks in the Majiagou Fm were presented, and for the first time, it was discovered and verified that there are effective scale source rocks with high organic abundance. Based on these analysis and studies, the following results were achieved. First, the effective source rocks of Majiagou Fm are composed of thin–thick layered dark dolomite-bearing mudstones, dolomitic mudstones and argillaceous dolomites, and their enrichment and distribution are obviously controlled by sedimentary facies. During the sedimentation of Majiagou Fm, the effective scale source rocks developed better at the regressive stage than at the transgressive stage. The effective source rocks are primarily distributed in the upper part of Ma 5 Member (especially concentrated in the third and fourth sub-members and secondly in Ma 3 Member, Ma 1 Member and the middle–lower part of Ma 5 Member. Second, the effective source rocks are areally distributed in a dual-girdle form around the Mizhi Salt Depression, and those in the secondary depressions are medium–thick layered, with a large total thickness and high organic abundance. Third, the effective source rocks in the center of Mizhi Depression and the secondary uplifts are thin-layered, with a small total thickness and low organic abundance. And fourth, the organic abundance of the effective source rocks varies from 0.30% to 8.45%. Phytoplankton and Acritarchs are the main parent materials of hydrocarbon, and organic matters are of sapropel or sapropel

  14. 鄂尔多斯盆地东缘上古生界页岩特征及含气量%Characteristics and Calculation Method for Gas Content of Upper Paleozoic Shales in the Eastern Margin of Ordos Basin

    郭少斌; 赵可英


    Shale sequences are well developed in the Carboniferous-Permian transition facies,Ordos Basin. Researchers have done many studies on shales in upper Paleozoic of the Ordos Basin. With few drilling data,however,not enough researches have been carried out on the eastern margin of the basin. In order to clarify the characteristic and gas bearing of shales in the eastern margin of the basin,according to the characteristic of sedimentary,geochemistry,lithology,physical property and the experiments of isothermal adsorption and nuclear magnetic resonance of samples from Taitou,the shales were analyzed. It is found that Taiyuan formation has the best condition for shale gas formation which is 25 meters thick,abundant in organic matter,and is in the stage of producing gaseous hydrocarbon,the shale is of high content of non swellable clay minerals and equally distributed crack/micro fractures. We also offer the calculation formula of gas adsorption using parameters of depth and content of organic carbon and improve the calculation accuracy of free volume through calculating effective porosity. It has been verified that the calculation of air content conforms to the actual situation,and the method is simple and practical by relevant data from Well Y88 in Ordos Basin.%鄂尔多斯盆地上古生界石炭二叠系海陆过渡相泥页岩发育,前人对盆地内上古生界泥页岩已做了多项研究,而盆地东缘钻井资料较少,研究程度较低。为了弄清盆地东缘泥页岩的特征及含气性,通过野外实测剖面台头剖面的沉积、地化、岩性、物性等参数并结合等温吸附、核磁共振实验结果,对盆地东缘泥页岩进行分析。研究认为:盆地东缘上古生界以太原组发育的泥页岩最佳,厚度25 m左右,有机质丰度较高,处于产气态烃阶段,泥页岩中非膨胀性黏土含量较高,裂缝/微裂缝发育程度较均匀;同时提出了应用深度和有机碳含量计算吸附气

  15. Complex Exploration Techniques for the Low-permeability Lithologic Gas Pool in the Upper Paleozoic of Ordos Basin

    FuJinhua; XiShengli; LiuXinshe; SunLiuyi


    The Ordos basin is a stable craton whose late Paleozoic undergoes two sedimentary stages: from the middlelate Carboniferous offshore plain to the Permian continental river and lake delta. Sandstones in delta plain channels, delta-front river mouth bars and tidal channels are well developed. The sandstones are distributed on or between the genetic source rocks, forming good gas source conditions with widespread subtle lithologic gas pools of low porosity, low permeability, low pressure and low abundance. In recent years, a series of experiments has been done, aimed at overcoming difficulties in the exploration of lithologic gas pools. A set of exploration techniques, focusing on geological appraisal, seismic exploration, accurate logging evaluation and interpretation, well testing fracturing, has been developed to guide the exploration into the upper Paleozoic in the basin, leading to the discoveries of four large gas fields: Sulige, Yulin, Wushenqi and Mizhi.

  16. Formats

    Gehmann, Ulrich


    Full Text Available In the following, a new conceptual framework for investigating nowadays’ “technical” phenomena shall be introduced, that of formats. The thesis is that processes of formatting account for our recent conditions of life, and will do so in the very next future. It are processes whose foundations have been laid in modernity and which will further unfold for the time being. These processes are embedded in the format of the value chain, a circumstance making them resilient to change. In addition, they are resilient in themselves since forming interconnected systems of reciprocal causal circuits.Which leads to an overall situation that our entire “Lebenswelt” became formatted to an extent we don’t fully realize, even influencing our very percep-tion of it.

  17. Petrology, phase equilibria and monazite geochronology of granulite-facies metapelites from deep drill cores in the Ordos Block of the North China Craton

    He, Xiao-Fang; Santosh, M.; Bockmann, Kiara; Kelsey, David E.; Hand, Martin; Hu, Jianmin; Wan, Yusheng


    Among the various Precambrian crustal blocks in the North China Craton (NCC), the geology and evolution of the Ordos Block remain largely enigmatic due to paucity of outcrop. Here we investigate granulite-facies metapelites obtained from deep-penetrating drill holes in the Ordos Block and report petrology, calculated phase equilibria and in-situ monazite LA-ICP-MS geochronology. The rocks we studied are two samples of cordierite-bearing garnet-sillimanite-biotite metapelitic gneisses and one graphite-bearing, two-mica granitic gneiss. The peak metamorphic age from LA-ICP-MS dating of monazite in all three samples is in the range of 1930-1940 Ma. The (U + Pb)-Th chemical ages through EPMA dating reveals that monazite occurring as inclusions in garnet are older than those in the matrix. Calculated metamorphic phase diagrams for the cordierite-bearing metapelite suggest peak P-T conditions ca. 7-9 kbar and 775-825 °C, followed by decompression and evolution along a clockwise P-T path. Our petrologic and age data are consistent with those reported from the Khondalite Belt in the Inner Mongolia Suture Zone in the northern part of the Ordos Block, suggesting that these granulite-facies metasediments represent the largest Paleoproterozoic accretionary belt in the NCC.

  18. Human induced dryland degradation in Ordos Plateau, China, revealed by multilevel statistical modeling of normalized difference vegetation index and rainfall time-series

    Jing ZHANG; JianMing NIU; Tongliga BAO; Alexander BUYANTUYEV; Qing ZHANG; JianJun DONG; XueFeng ZHANG


    Land degradation causes serious environmental problems in many regions of the world, and although it can be effectively assessed and monitored using a time series of rainfall and a normalized difference vegetation index (NDVI) from remotely-sensed imagery, dividing human-induced land degradation from vegetation dynamics due to climate change is not a trivial task. This paper presented a multilevel statistical modeling of the NDVI-rainfall relationship to detect human-induced land degradation at local and landscape scales in the Ordos Plateau of Inner Mongolia, China, and recognized that anthropogenic activities result in either positive (land restoration and re-vegetation) or negative (degradation) trends. Linear regressions were used to assess the accuracy of the multi-level statistical model. The results show that:(1) land restoration was the dominant process in the Ordos Plateau between 1998 and 2012;(2) the effect of the statistical removal of precipitation revealed areas of human-induced land degradation and improvement, the latter reflecting successful restoration projects and changes in land man-agement in many parts of the Ordos; (3) compared to a simple linear regression, multilevel statistical modeling could be used to analyze the relationship between the NDVI and rainfall and improve the accuracy of detecting the effect of human activities. Additional factors should be included when analyzing the NDVI-rainfall relationship and detecting human-induced loss of vegetation cover in drylands to improve the accuracy of the approach and elimi-nate some observed non-significant residual trends.

  19. Detection of gas reservoirs by the joint use of P- and PS-waves: A case study on the Ordos basin, China

    Xiucheng Wei; Xiangyang Li; Yang Liu; Songqun Shi; Weidong Jiang


    We present an example of using converted-waves for characterizing onshore gas reservoirs in the Ordos basin in Northwest China. The Ordos basin is the largest gas province in China. The main gas reservoirs (about 3 300 m in depth) are in upper Paleozoic sandstone that has low or reversed P-wave impedance and is immediately above a coal seam. This makes it very difficult to image the gas reservoirs using conventional P-wave data. Analysis of core, log and VSP data shows a weak PP reflection but a relatively strong PS-converted wave reflection, or both strong PP- and PS-reflections but with opposite polarity from the gas bearing sands, which indicates the potential of using PS-waves to image the gas reservoirs in the Ordos basin. Subsequently, thirteen seismic lines were acquired, processed and interpreted to verify the PP- and PS-responses, and two corresponding attributes (PP- and PS- amplitude ratio and polarity ratio) are used to map the reservoirs through joint PP and PS analysis.

  20. 大牛地气田下石盒子组岩相-测井相与砂体储集关系及其平面分布的油气意义%Relationships between lithofacies-logging facies and sandbody reservoir properties and the petroleum geological significance of lithofacies-logging facies horizontal distribution of Xiashihezi Formation in Daniudi gas field, Ordos Basin, China

    常兴浩; 田景春; 李良; 张翔; 李蓉; 古娜; 杨忠亮


    Taking Xiashihezi Formation in the Daniudi gas field as the research object and using the data of the drilling cores,logging,properties and productive capacity,etc.,this paper studies the relationship between different lithofacies-logging facies and reservoir sandbody properties and productive capacity in detail.The results show that the reservoir sandbody containing pebbly coarsegrained sandstone lithofacies whose gamma well log is box shape has the best physical property and the highest productive capacity,that the reservoir sandbody containing coarse-grained sandstone and medium-grained sandstone facies whose gamma well log is bell shape or dentation box shape has better physical property and middle productive capacity,and that the reservoir sandbody containing finegrained sandstone facies whose gamma well log is funnel shape has poor physical property and low productivity.Based on the statistical analysis of the superior lithofacies-logging facies,of more than 700 wells in study area and according to the plane distribution characteristics of the sedimentary microfacies and the sandbody,taking the He 3-1 small layer for example,the authors make the lithofacies-logging facies plane distribution map of the He 3-1 small layer,and depict the plane distribution characteristics of the superior lithofacies-logging facies of the He 3-1 small layer.The plane distribution map reflects the distribution rule of the physical property and production ability and also highlights the plane distribution of the gas reservoir sandbody.The achievements provide the forecast basis for appraising the traps of lithology.%以鄂尔多斯盆地大牛地气田上古生界下石盒子组为研究对象,利用钻井岩心、测井、物性和产能等资料,研究不同岩相-测井相与储集砂体物性及产能的关系,结果表明:(含砾)粗粒砂岩相(箱形)储集砂体物性最好,产能最高;其次为粗粒砂岩相-中粒砂岩相(伽马测井曲线为钟形或齿状箱形)储

  1. Environmental Redox Changes of the Ancient Sea in the Yangtze Area during the Ordo-Silurian Transition

    YAN Detian; CHEN Daizhao; WANG Qingchen; WANG Jianguo; CHU Yang


    Extensive organic-matter (OM) rich facies (black shales) occur in the Ordo-Silurian boundary successions in the Yangtze area, South China. To investigate the redox changes of the Yangtze Sea during the Ordo-Silurian transition, two OM sections (Wangjiawan in Yichang, Hubei Province, and Sanjiaguan in Zhangjiajie, Hunan Province) straddling the Ordo-Silurian boundary are studied. The measurements finished in this study include contents of the total organic carbon (TOC), pyrite sulphur, and different species of Fe, including dithionite-extractable Fe (Feo), pyrite Fe (Fee), HCl-extractable Fe (Fen), and total Fe (Fer), in black shales, as well as other redox proxies, such as theS/C ratio, the ratio between highly reactive Fe (FeHR = FeD + Fee) and FeT, and the Fev/(Fep + FeH) ratio, known as the degree of pyritization (DOP). In the Wangjiawan section, the Middle Ashgill sediments have high FeHR/Fer ratios (0.20-0.77; avg. 0.45), high DOP values (0.21-0.72; avg. 0.54), and a relatively constant sulfur content independent of the organic carbon content. By the contrast, the mid-early Hirnantian deposits generally have low FeI.FeHR/Fer ratios (0.10-4).35; avg. 0.21), low DOP values (0.11- 0.40; avg. 0.28), and S/C values are clnstering on the normal marine value (S/C = 0.36). The late Hirnantian and early Rhuddanian deposits, similar to those of the Middle Ashgill deposits, are characterized by high FeHR/FeT ratios (0.32-0.49; avg. 0.41), high DOP values (0.46-0.68; avg. 0.53) and fairly constant sulfur contents. These data suggest the occurrences of marine anoxia on the Yangtze Sea shelf during intervals of the Mid Ashgill, Late Hirnantian and Early Rhuddanian, and ventilated and oxygenated marine conditions during the mid-early Hirnantian time. The mid-early Hirnantian ventilated event was concomitant with the global glacial period, likely resulted from the glacio-enstatic sea-level fall and subsequent circulation of cold, dense oxygenated waters upon the sheff seabed

  2. Ordo amoris: fenomenoloqía del amor en Max Scheler, orden y desorden del corazón humano

    Juan Mansilla Sepulveda


    Full Text Available Este trabajo presenta lo fenomenologia scheleriana del amor tomada del acervo agustiniano que concibe o orda amoris como el núcleo principal del ethos de un hombre o uno colectividad humana: todo el obrar moral social nace de un amor fundamental, y ese amor es, a su vez, una amor plural, dirigido a muchos géneros de cosas, pero ordenado segun un orden de importancia de éstos. Es, lisa y llanamente pre-dilección. Las verdades se van fundando, en esencia, desde el orden y el desorden del corazón humano. El concepto de un ordo amoris tiene así una significación doble: una significación normativo y una significación descriptiva. Los resultados de este estudio se orientan a que lo supremo a que el hombre puede aspirar, es amor las cosas, en la medida de lo posible, tal como Dios las ama, y vivir con evidencia, en el propio acto del amor, la coincidencio entre el acto divino y el acto humano en un mismo punto del mundo de los valores, indistintamente del juicio de la existencia de Dios.

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


    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.

  4. Fission-track-age records of the Mesozoic tectonic-events in the southwest margin of the Ordos Basin, China

    CHEN; Gang; SUN; JianBo; ZHOU; LiFa; ZHANG; HuiRuo; LI; XiangPing; WANG; ZhiWei


    Based on the analysis of apatite and zircon fission track (FT), the FT age distribution and the peck-ages of the Mesozoic tectonic events in the southwest margin of the Ordos Basin (OB) were discussed. (1) The early event mainly occurred at 213-194 Ma with a peck-age of 205 Ma, and corresponded to the tectonic uplift and the mega-clastic deposit in the southwest OB during the Late Triassic. (2) The middle event included at least two episodes. One was at 165-141 Ma with a peck-age of 150 Ma, and the other was at 115-113 Ma with a peck-age of 114 Ma, corresponding to the over-thrusting and the mega- clastic deposits in the southwest OB during the Late Jurassic to the Early Cretaceous. (3) The late event mainly demonstrated the regional uplifting and included at least two episodes. One was at 100-81 Ma with a peck-age of 90 Ma, and the other was at 66-59 Ma with a peck-age of 63 Ma. Additionally, the relationship analysis of the tectonic event and the mineralizing chronology revealed that the extreme environment of the peck-age event and the subsequent moderate activity could be the key factors of the multiple resources coupling and coexistence in the OB.

  5. On the development mechanism of the lacustrine high-grade hydrocarbon source rocks of Chang 91 member in Ordos Basin


    As revealed from recent drilling and organic geochemical testing and research, a series of lacustrine high-grade hydrocarbon source rocks was discovered in the upper section of the Chang 9 oil reservoir member of upper Triassic in Ordos Basin. The hydrocarbon source rocks show average TOC content as high as 5.03%, average bitumen "A" content as high as 0.8603%, and good quality organic precursors, which are of the sapropelic type mainly derived from lower aquatic plants and have reached the thermal evolution stage featured by oil-producing climax. Generally the lacustrine high-grade hydrocarbon source rocks were developed in local depressions of a lake basin, and the Chang 91 member was particularly formed in a depositional environment characterized by fresh water to weakly saline water, weakly oxidizing to weakly reducing setting and semi-deep lake facies, as was demonstrated by a variety of organic to inorganic geochemical parameters. As a result, high productivity constitutes the principal controlling force for generation of this series of high-grade hydrocarbon source rocks. Deposition of thinly-bedded and laminated tuffs as well as positive Eu anomaly corroborate the possible occurrence of anoxic geological event closely related to contemporaneous volcanic eruption, which would play a key part in development of the Chang 91 member of high-grade hydrocarbon source rocks.

  6. 鄂尔多斯市家蝇抗药性调查分析%Insecticide resistance in Musca domestica in Ordos

    王玲芳; 海玉和; 白长义; 高慧; 蔺权德


    Objective To determine current resistance to commonly used insecticides in the natural population of Musca domestica in Ordos city, in order to evidence for proper application of insecticides for fly control. Methods Topical application method was used in the study. Results The natural populations of M. Domestica in Ordos city had developed various degrees of resistances to dichlorovos, deltamethrin and beta-cypermethrin, with resistance ratios of 19.39, 48.05, and 407.69, respectively. Propoxur resulted in low fatality in M. Domestica. Conclusion The natural populations of M. Domestica in Ordos city had low resistance to dichlorovos and high resistance to deltamethrin and beta-cypermethrin. Propoxur had a low lethality rate in the flies.%目的 了解鄂尔多斯市近年来家蝇自然种群对常用卫生杀虫剂的抗药性现状,为合理使用杀虫剂和指导灭蝇工作提供依据.方法 采用微量点滴法.结果 鄂尔多斯市家蝇自然种群对敌敌畏、溴氰菊酯、高效氯氰菊酯已呈现出不同程度的抗药性,抗性倍数依次为19.39、48.05和407.69倍,残杀威对家蝇的致死率较低.结论 鄂尔多斯市家蝇自然种群对敌敌畏的抗药性较低,对溴氰菊酯和高效氯氰菊酯呈现高抗水平,对残杀威致死率较低.

  7. Satellite Monitoring the Spatial-Temporal Dynamics of Desertification in Response to Climate Change and Human Activities across the Ordos Plateau, China

    Qiang Guo


    Full Text Available The Ordos Plateau, a typical semi-arid area in northern China, has experienced severe wind erosion events that have stripped the agriculturally important finer fraction of the topsoil and caused dust events that often impact the air quality in northern China and the surrounding regions. Both climate change and human activities have been considered key factors in the desertification process. This study used multi-spectral Landsat Thematic Mapper (TM, Enhanced Thematic Mapper Plus (ETM+ and Operational Land Imager (OLI remote sensing data collected in 2000, 2006, 2010 and 2015 to generate a temporal series of the modified soil-adjusted vegetation index (MSAVI, bare soil index (BSI and albedo products in the Ordos Plateau. Based on these satellite products and the decision tree method, we quantitatively assessed the desertification status over the past 15 years since 2000. Furthermore, a quantitative method was used to assess the roles of driving forces in desertification dynamics using net primary productivity (NPP as a commensurable indicator. The results showed that the area of non-desertification land increased from 6647 km2 in 2000 to 15,961 km2 in 2015, while the area of severe desertification land decreased from 16,161 km2 in 2000 to 8,331 km2 in 2015. During the period 2006–2015, the effect of human activities, especially the ecological recovery projects implemented in northern China, was the main cause of desertification reversion in this region. Therefore, ecological recovery projects are still required to promote harmonious development between nature and human society in ecologically fragile regions like the Ordos Plateau.

  8. 鄂尔多斯盆地西缘奥陶纪生物礁及其储集性能%Ordovician organic reefs and their reservoir property on the west margin of Ordos Basin, China

    周俊烈; 陈洪德; 赵俊兴; 苏中堂; 张成弓; 王玉萍; 郝哲敏


    Based on the sedimentary and petroleum geology theory and through the observation of outcrops, cores, and slices and testing analysis, the authors study the Ordovician organic reefs on the west margin of Ordos Basin. The authors reach out a conclusion that the Ordovician organic reefs on the west margin of Ordos Basin are the coral reefs of the Lower Ordovician Zhuozishan Formation located in Wuhai Zhuozishan in the north, the stromatoporoids-sponge reefs of the Lower Ordovician Kelimoli Formation of Well Qitan 1 in the middle and the coral reefs of the Upper Ordovician Beiguoshan Formation in Shijiezigou in the south. The reefs in the north develop earlier than that in the south. The north reefs have grown 2 — 3 phases and that in the south 4 phases. The aquatic environment of the reefs in the north is relatively shallow and the reefs in the south has a deep aquatic environment. The coexistence of different shoals and the reefs develops the reef-bank reservoirs. The reservoir spaces are mainly the organic lattice poles and dissolved poles dissolved by fabrics selectively. The physical conditions show the reservoir property is poor. But, the reefs located on the platform margin are beneficial to developing the reef-bank reservoirs, so the platform margin can be the exploration target.%应用沉积学和石油地质学理论,通过野外剖面观测、岩心观察、室内薄片和测试分析,对鄂尔多斯盆地西缘奥陶纪生物礁进行了详细研究,认为有北部的乌海桌子山地区下奥陶统桌子山组珊瑚生物礁,中部的棋探1井下奥陶统克里摩里组层孔虫—海绵生物礁和南部的石节子沟上臭陶统背锅山组珊瑚生物礁.北部生物礁发育的时代早,南部晚;北段礁体生长发育2~3期,南段发育可达4期;北段及南段生物礁生长的水体环境相对较浅,中部相对较深.生物礁与各种滩共生,发育礁滩型储层,生物格架孔和组构选择性溶蚀的溶孔是其主要储集

  9. Quantification of the sources of long-range transport of PM2.5 pollution in the Ordos region, Inner Mongolia, China.

    Khuzestani, Reza Bashiri; Schauer, James J; Wei, Yongjie; Zhang, Lulu; Cai, Tianqi; Zhang, Yang; Zhang, Yuanxun


    The Ordos region of Inner Mongolia is rapidly developing and suffers from poor air quality and unhealthy levels of fine particulate matter. PM2.5 concentrations in the Ordos region were found to exceed 75 μg/m(3) on average, annually, with peak pollution days in excess of 350 μg/m(3), but local air pollution emissions from surrounding sources are not sufficient to drive pollution levels to these concentrations. The current study was designed to quantify sources of PM2.5 and assess the local source contributions and effects of regional transport on local pollution. The results show that the Ordos region is primarily impacted by regional long-range transport of pollutants from anthropogenic sources located outside of the Inner Mongolia in Shanxi province areas but is also largely affected by regional dust transported from the deserts located in western Inner Mongolia. The analysis proved that approximately 77% of PM2.5 mass is transported long-range from the sites exterior to the study area and contributes 59.32 μg/m(3) on average, annually, while the local sources contribute 17.41 μg/m(3) (23%) on annual average to the PM2.5 mass in the study area. High spatial correlation coefficients (R(2) > 0.6) were observed for most of the factors pointing to the transport of external emissions into the area. Spatial correlation analysis, bivariate polar plots and hybrid trajectory models for industrial and secondary inorganic factors provide evidence for the impact of long-range transport from Shanxi province areas. In addition, the deserts in western Inner Mongolia were found to be the source regions for dust. Finally, our analysis shows that the source of oil combustion and mobile factors are impacted by local sources in the Ordos region; however, some regional impacts from other regions were also observed for mobile source in the area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Expériences religieuses en contexte urbain. De l'ordo monasticus aux religiones novæ : le jalon du monachisme militaire

    Carraz, Damien

    2013-01-01; International audience; Les ordres militaires sont-ils les "fils" de la révolution urbaine du XIIe siècle ? Représentent-ils en cela un jalon qui aiderait à comprendre le passage de l'ordo monasticus traditionnel aux "Religiones novæ" du XIIIe siècle incarnées par l'expérience mendiante ? Pour tenter de mieux comprendre les modalités de l'inurbamento des ordres militaires, on s'efforce d'abord de situer brièvement ces derniers au s...

  11. Adaptive Fusion of Information for Seeing into Ordos Basin, China: A China-Germany-US Joint Venture.

    Yeh, T. C. J.; Yin, L.; Sauter, M.; Hu, R.; Ptak, T.; Hou, G. C.


    Adaptive fusion of information for seeing into geological basins is the theme of this joint venture. The objective of this venture is to initiate possible collaborations between scientists from China, Germany, and US to develop innovative technologies, which can be utilized to characterize geological and hydrological structures and processes as well as other natural resources in regional scale geological basins of hundreds of thousands of kilometers (i.e., the Ordos Basin, China). This adaptive fusion of information aims to assimilate active (manmade) and passive (natural) hydrologic and geophysical tomography surveys to enhance our ability of seeing into hydrogeological basins at the resolutions of our interests. The active hydrogeophysical tomography refers to recently developed hydraulic tomgoraphic surveys by Chinese and German scientists, as well as well-established geophysical tomography surveys (such as electrical resistivity tomography, cross-borehole radars, electrical magnetic surveys). These active hydrogeophysical tomgoraphic surveys have been proven to be useful high-resolution surveys for geological media of tens and hundreds of meters wide and deep. For basin-scale (i.e., tens and hundreds of kilometers) problems, their applicabilities are however rather limited. The passive hydrogeophysical tomography refers to unexplored technologies that exploit natural stimuli as energy sources for tomographic surveys, which include direct lightning strikes, groundwater level fluctuations due to earthquakes, river stage fluctuations, precipitation storms, barometric pressure variations, and long term climate changes. These natural stimuli are spatially varying, recurrent, and powerful, influencing geological media over great distances and depths (e.g., tens and hundreds of kilometers). Monitoring hydrological and geophysical responses of geological media to these stimuli at different locations is tantamount to collecting data of naturally occurring tomographic

  12. Origin and Accumulation of Natural Gases in the Upper Paleozoic Strata of the Ordos Basin in Central China

    ZHU Yangming; WANG Jibao; LIU Xinse; ZHANG Wenzheng


    The natural gases in the Upper Paleozoic strata of the Ordos basin are characterized by relatively heavy C isotope of gaseous alkanes with δ13C1 and δ13C2 values ranging mainly from-35‰ to -30‰ and-27‰ to-22‰,respectively,high δ13C excursions (round 10)between ethane and methane and predominant methane in hydrocarbon gases with most C1/(C1-C5)ratios in excess of 0.95, suggesting an origin of coal-derived gas.The gases exhibit different carbon isotopic profiles for C1.C4 alkanes with those of the natural gases found in the Lower Paleozoic of this basin.and believed to be originated from Carboniferous-Permian coal measures.The occurrence of regionally pervasive gas accumulation iS distinct in the gently southward-dipping Shanbei slope of the central basin.It is noted that molecular and isotopic composition changes of the gases in various gas reservoirs are associated With the thermal maturities of gas source rocks.The abundances and δ13C values of methane generally decline northwards and from the basin center to its margins.and the effects of hydrocarbon migration on compositional modification seem insignificant.However, C isotopes of autogenetic calcites in the vertical and lateral section of reservoirs show a regular variation,and are as a whole depleted upwards and towards basin margins.Combination with gas maturity gradient, the analysis could be considered to be a useful tool for gas migration.

  13. Oil/Gas Accumulation Characteristics and Exploration Methods of the Deltaic Lithologic Reservoirs in Northern Shaanxi Area

    YangHua; FuJinhua; YuJian; DuJinliang; MuJingkui


    There are large deltaic systems in the Triassic Yanchang Formation in the northern Shaanxi area of the Ordos Basin, and developed two sets of good source-reservoir-caprock assemblages and many sets of oil-beating beds. Exploration experience demonstrates that the formation and distribution of the reservoir were controlled by the generative depression of the Yanchang Formation, and deltaic reservoir sand body is the material basis for large-scale oilfields. In addition, secondary laumontite in a low permeable area was dissolved and then a high permeable area was formed. The updip lithologic variety of reservoir sand bodies is favorable to the formation of subtle lithologic traps, and the deltaic reservoirs are characterized by large multi-beds of oil-generation and abundant hydrocarbon resources. In this paper, the petroleum geologic settings of the studied area are analyzed, and the accumulation characteristics and exploration methods of lithologic reservoirs are summarized. It is of theoretical significance for the study of the exploration theories of lithologic reservoirs, and also expedites the exploration steps of deltaic reservoirs in the northern Shaanxi area.

  14. Ecotourism and nature-reserve sustainability in environmentally fragile poor areas: the case of the Ordos Relict Gull Reserve in China

    Xueli Li


    Full Text Available This article explores the applicability of the conventional wisdom that economic growth is paramount to environmental sustainability by examining ecotourism and nature-reserve sustainability in environmentally fragile poor regions. The discussion focuses on the Ordos Relict Gull Reserve in the Inner Mongolia region of China. The study evaluated reserve records of water and soil conditions and interpreted satellite images to identify lake-level and land-cover changes at the reserve. The Ordos Relict Gulls seem to have abandoned the reserve following ecotourism development and established new colonies in northern Shaanxi. We argue that ecotourism—especially ersatz ecotourism—in certain nature reserves is an unsustainable practice rooted in the conventional wisdom that economic development spurs environmental protection as suggested by the environmental Kuznets curve (EKC. The article concludes that environmental protection rather than economic growth is of vital importance in nature-society interactions in environmentally fragile poor areas. We call for prohibitions on tourism in such nature reserves to enhance sustainability.

  15. Application of Effective Porosity Model to Tight Gas Sands in Ordos Basin%等效孔隙结构模型在鄂尔多斯致密含气砂岩中的应用

    周枫; 徐鸣洁; 马中高


    Core samples from a well in Ordos basin are used to study the elastic properties of tight gas sands in lower Shihezi Formation. Elastic parameters are measured at in-situ physical conditions. The total pore space is divided into three space types based on the microscopic analyses. Soft porosity model (SPM) is modified to construct a new model which could represent the tight gas sands reservoir. A modeling example using the well-log data from Daniudi gas field is completed using self-consistent theory. Model predicted results include Vp, Vs, Poisson’s ratio, acoustic impedance of P wave and acoustic impedance of S wave. Comparison of those elastic properties derived from the model, well-log, and core sample measurement is conducted to evaluate the new model. Predicted Vp, Vs are overall in agreement with well-log data. The same agreement also appears in Poisson’ s ratio curve. But the model predicts a slightly different behavior of rocks from the core samples in the impedance of P wave (AIp) and acoustic impedance of S wave (AIs). Predicted AIp and AIs are slightly higher than those of core samples. Pressure may be the main factor responsible for the difference between the model and core samples. The AIp and AIs are calculated from velocity and density, which are derived from the well-log data. The density in-situ condition is higher than what is measured in laboratory because of the pressure produced by upper strata. So the predicted AIp and AIs show a slight rise in comparison to the core samples. This article provides a good example of applying SPM to tight gas sands of Ordos, and show that the model will be very helpful to predict elastic properties of tight gas reservoirs.%该文作者采集了鄂尔多斯大牛地气田二叠系下石盒子组钻井岩芯,在60 Mpa围压和50℃温度下进行了岩芯弹性参数测试。通过岩石薄片分析孔隙结构特征,按照孔隙的纵横比值(0.9)将孔隙划分为三类,进而对柔性孔隙模

  16. Modes of Occurrence and Cleaning Potential of Trace Elements in Coals from the Northern Ordos Basin and Shanxi Province, China

    WANG Wenfeng; QIN Yong; JIANG Bo; FU Xuehai


    Based on the analyses of 43 elements in 16 samples of the raw coal and feed coal collected from the northern Ordos basin and Shanxi Province, the modes of occurrence of these elements were studied using the method of cluster analysis and factor analysis, and the cleaning potential of the hazardous elements relatively enriched in the coals was discussed by analyzing six samples of the cleaned coal from the coal-washing plants and coal cleaning simulation experiments. The results shows that the elements Br and Ba show a strong affinity to the organic matter, Cs, Cd, Pb, Zn and Hg partly to the organic matter, and the other trace elements are mainly associated with the mineral matter. Cs, Mo, P, Pb,Zn and S have positive correlations with the two principal factors, reflecting the complexity of their modes of occurrence.Some elements that were thought to show a faint relationship (Be with S and Sb with carbonates) in other rocks are found to have a strong interrelation in the coals. Clay minerals (mainly kaolinite) dominate in the coals, and Ta, Th, Ti, Sc, REE,Hf, U, Se, W, V, Nb, Mo, Al, P, Cr, Pb and Zn are distributed mostly in kaolinite, while K, Rb, Cs, and Na have much to do with illite. Conventional cleaning can reduce the concentrations of most hazardous elements in various degrees. The hazardous elements S, As, Sb, Se, Mo, Pb, Cd and Hg relatively enriched in some coals from the area studied have a relatively high potential of environmental risks. However, by physical coal cleaning processes, more than 60% of As and Hg were removed, showing a high degree of removal, more than 30% of Sb, as well as S, Pb and Cd partly associated with the inorganic matter were removed. Se and Mo showing a relatively low degree of removal could be further removed by deep crushing of the coal during physical cleaning processes, and the concentrations of S, Pb, Cd and Hg with a partial association with the organic matter could be decreased in such ways as the coal blending

  17. Development of the Extra-low Permeability Oilfield of Ansai

    Hu Wenrui


    @@ Reservoir Characteristics Ansai Oilfield is located in Ordos Basin. Its regional structure is a large westward-dipping monocline with dip angle less than 1°. The main producing interval is in Yanchang formation,Triassic, and the depositional environment is a delta deposit of inland fresh water lake. This oilfield is distributed in distributary channel sandstone of delta plain,front underwater distributary channel sandstone and front river mouth bar sandstone of flowershape. Lithologic trap is the primary trap type and shows complex rhythm with average reservoir thickness of 11 to 15 m and Average porosity of 11% to14%. It is fine grained and well sorted sandy arkose. The cementing material is predominantly secondary chlorite, secondary laumontite and calcite with content of 11% to 14%.

  18. 鄂尔多斯盆地吴起-甘泉地区奥陶系古地貌恢复研究%Study on the Palaeogeomorphology Restoration of Ordovician in Wuqi-Ganquan area of Ordos Basin

    吴海燕; 曹红霞; 于珺; 孙建博; 乔向阳; 强娟; 尚婷; 罗腾跃


    依据研究区215口探井的钻井、测井资料,运用沉积地质学、古地理学等方法,对鄂尔多斯盆地古隆起东侧吴起—志丹—甘泉地区的奥陶系马家沟组风化壳岩溶古地貌进行恢复。分别选取本溪组顶8号煤层和马家沟组马五41底部的凝灰岩层为作图基准面,综合利用古地质图法、“印模法”和“残厚法”,并结合铝土岩分布数据,对研究区岩溶古地貌进行恢复。同时,根据研究区不整合面上下地层厚度的组合可以划出上薄+下薄型、上薄+下厚(相对)型、上厚+下薄(相对)型等模型,自西向东将研究区岩溶古地貌划分出2个二级古地貌单元(岩溶高地、岩溶斜坡)和3个三级古地貌单元(潜台、残丘、古沟槽)。%On the basis of drilling and logging data from the 215 wells in the study area, and by means of sedimentary geol-ogy and paleogeography methods, the weathering crust karst paleogeomorphology of Ordovician Majiagou formation in wuqi-zhidan-ganquan area, where is at the eastern side of paleo uplift, has been restored in Ordos Basin. Taken the No. 8 coal seam at the top of Benxi formation and the tuff at bottom of Majiagou five 41 formation as the map reference plane, Compre-hensive utilization of the ancient geological map method impression method and residual thickness method, combined with the data of bauxite that distributed in Ordovician. At the same time, the models can be divided into “up thin plus lower thin”, “up thin plus lower thick”, “up thick plus lower thin” according to the thickness of strata unconformity, hereby the karst palaeogeomorphology also divided into two 2-level units, i. e. karst heights and karst slopes, and three 3-level u-nits, i. e. Hidden units, monadnock and trench, order.

  19. CO2 Storage and Surface Flooding Process of Wu 38 Well Block in Yanchang Oilfield%延长油田吴38井区CO2埋存与驱油地面工艺

    陈龙龙; 江绍静; 杨永超; 黄春霞; 余华贵; 白成来


    3 movable injection stations have been built in Wu38 well block of YanChang Oilfield. At the same time, five gas injection wells can be gas injected, which involving 24 production Wells. It is the first standardization surface process system that CO2 storage and CO2-EOR in the northwest.The system main body consists of two big modules:low pres-sure and high pressure. Low pressure module includes CO2 storage tank, CO2 feeding and circulation area, supercharging area; high-pressure module includes CO2 injection and loop area, auxiliary monitoring system. After the surface process system put into use, the single well CO2 injection rate is 25 t/d, it can realize automatic monitoring and data storage. Ac-cording to the forecast, the oil recovery of CO2 flooding is 10.79% higher than that of water flooding, which has the vital significance to the reduction of CO2 greenhouse gas emissions and low permeability reservoir development.%延长油田吴38井区已建成3座橇装式注入站,可同时对5口井实施注气,涉及24口生产井受效。它是西北第一个实施CO2埋存与驱油的标准化地面工艺系统,系统主体由低压及高压两大模块组成,低压模块包括CO2存储区、CO2喂液及循环区、增压区,高压模块包括CO2注入及循环区、辅助监测系统。地面工艺系统投入使用后,单井注入量为25 t/d,可实现数据全自动监控和存储。根据预测,原油采收率与水驱相比提高10.79%,这对减少CO2温室气体排放及低渗油藏开发具有重要的意义。

  20. An approach to noble-gas isotopic compositions in natural gases and gas-source tracing in the Ordos Basin, China


    Isotopic compositions of noble gases, i.e. He Ar Kr and Xe, are measured in natural gases from the Zhongbu gasfield in the Ordos Basin. And heavy noble-gas isotopes (Kr, Xe) are here first used in geochemically studying natural gases and gas-source correlation. Isotopic compositions of heavy noble gases in natural gases, especially Xe, show two-source mixing in the Zhongbu gasfield. Gas sources are somewhat different in the northeast and the southwest of the gasfield. Generally, the gas source of the Lower Paleozoic makes a greater contribution in the southwest than in the northeast in the field. Two kinds of gases can be differentiated from isotopic compositions of heavy noble gases and from their relation with the Ar isotopic composition, Therefore, the comprehensive study on isotopic compositions of light and heavy noble gases can supply more useful information on gas-source correlation and tracing.

  1. Storage of biomass and net primary productivity in desert shrubland of Artemisia ordosica on Ordos Plateau of Inner Mongolia,China

    JIN Zhao; QI Yu-chun; DONG Yun-she


    Biomass and net primary productivity (NPP) are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season (June-October) of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season (p>0.1), but annual biomass varied significantly (p< 0.01). In the A.ordosica community, shrub biomass storage was 699.76 1246.40 g·m-2 and annual aboveground NPP was 224.09 g·m-2·a-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions (cover and height) and could be well predicted by shrub volume using power regression.

  2. Primary migration and secondary alteration of the Upper Paleozoic gas reservoir in Ordos Basin,China―Application of fluid inclusion gases


    The composition of fluid inclusions(FI)often represents the initial geochemical characteristics of palaeo-fluid in reservoir rock.Influence on composition and carbon isotopic composition of gas during primary migration,reservoir-forming and subsequent secondary alterations are discussed through comparing fluid inclusion gas with coal-formed gas and natural gas in present gas reservoirs in the Ordos Basin.The results show that primary migration of gas has significant effect on the molecular but not on the carbon isotopic composition of methane.Migration and diffusion fractionation took place during the secondary migration of gas in Upper Paleozoic gas reservoir according to carbon isotopic composition of methane in FIs.Composition and carbon isotopic composition of natural gas were nearly unchanged after the gas reservoir forming through comparing the FI gases with the natural gas in present gas reservoir.

  3. Oxygen and Hydrogen Isotopes of Waters in the Ordos Basin,China: Implications for Recharge of Groundwater in the North of Cretaceous Groundwater Basin

    YANG Yuncheng; SHEN Zhaoli; WENG Dongguang; HOU Guangcai; ZHAO Zhenhong; WANG Dong; PANG Zhonghe


    Hundreds of precipitation samples collected from meteorological stations in the Ordos Basin from January 1988 to December 2005 were used to set up a local meteoric water line and to calculate weighted average isotopic compositions of modern precipitation.Oxygen and hydrogen isotopes, with and gradually decrease in summer and fall,illustrating that the seasonal effect is considerable.They also show that the isotopic difference between south portion and north portion of the Ordos Basin are not obvious.and the isotope in the middle portion iS normally depleted.The isotope compositions of 32 samples collected from shallow groundwater(less than a depth of 150 m)in desert plateau range from for JD.Most of them are identical with modern precipitation.The isotope compositions of 22 middle and deep groundwaters(greater than a depth of 275 m)fall in ranges from-11.6‰to-8.8‰with an average of-10.2‰ for £18O and from-89‰ to-63‰ with an average of-76‰ for £D.The average values are significantly less than those of modern precipitation,illustrating that the middle and deep groundwaters were recharged at comparatively lower air temperatures.Primary analysis of 14C shows that the recharge of the middle and deep groundwaters started at late Pleistocene.The isotopes of 13 lake water samples collected from eight lakes define a local evaporation trend,with a relatively flat slope of 3.77,and show that the lake waters were mainly fed by modern precipitation and shallow groundwater.

  4. The components and carbon isotope of the gases in inclusions in reservoir layers of Upper Paleozoic gas pools in the Ordos Basin,China


    The components and carbon isotope of gases in inclusions are one of the most important geochemical indexes for gas pools.The analysis results of the components and carbon isotope of gases from inclusions in reservoir layers of Upper Palaeozoic gas pools in the Ordos Basin show that most inclusions grown in reservoir sandstone are primary inclusions.There is only a little difference about the components and carbon isotope between the well gases and the secondary inclusions gases.This indicated that the epigenetic change of gas pools is little.This difference between the well gases and the secondary inclusions gases is caused by two reasons:(i)The well gases come from several disconnected sand bodies buried in a segment of depth,while the inclusion gases come from a point of depth.(ii)The secondary inclusions trapped the gases generated in the former stage of source rock gas generation,and the well gases are the mixed gases generated in all the stages.It is irresponsible to reconstruct the palaeo-temperature and palaeo-pressure under which the gas pool formed using carbon dioxide inclusions.

  5. Identification of the hydrogeochemical processes and assessment of groundwater quality using classic integrated geochemical methods in the Southeastern part of Ordos basin, China.

    Yang, Qingchun; Li, Zijun; Ma, Hongyun; Wang, Luchen; Martín, Jordi Delgado


    Insufficient understanding of the hydrogeochemistry of aquifers makes it necessary to conduct a preliminary water quality assessment in the southern region of Ordos Basin, an arid area in the world. In this paper, the major ions of groundwater have been studied aiming at evaluating the hydrogeochemical processes that probably affect the groundwater quality using 150 samples collected in 2015. The two prevalent hydrochemical facies, HCO3Mg·Na·Ca and HCO3Mg·Ca·Na type water, have been identified based on the hydrochemical analysis from Piper trilinear diagram. Compositional relations have been used to assess the origin of solutes and confirm the predominant hydrogeochemical processes responsible for the various ions in the groundwater. The results show that the ions are derived from leaching effect, evaporation and condensation, cation exchange, mixing effect and human activities. Finally groundwater quality was assessed with single factor and set pair methods, the results indicate that groundwater quality in the study region is generally poor in terms of standard of national groundwater quality. The results obtained in this study will be useful to understand the groundwater quality status for effective management and utilization of the groundwater resource. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Landscape Application of the Vine in Ordos%藤本植物在鄂尔多斯地区的园林应用初探

    张晓娇; 李欣; 杨絮茹; 李瑞娟; 吴建华


    Using climbing plants for vertical greening is an important path to expand the green space,in-crease the amount of garden city and improve the ecological environment. As area available for garden af-forestation is becoming smaller and smaller,making full use of climbing plants for creating garden land-scape has become the current focus. in this paper,we aim to discuss the vine rescourse in Ordos,land-scape application form and development and utilization value vine rescourse,so as to provide the theoreti-cal basis for their introduction to landscaping.%藤本植物进行垂直绿化是拓展城市绿化空间、提高绿化覆盖率、改善生态环境的重要途径。随着城市园林绿化面积愈来愈小,利用藤本植物营造园林绿化景观已成为当下热点。本文主要对鄂尔多斯地区藤本植物资源、园林绿化应用方式及具开发价值的藤本植物资源进行了初步探讨,旨在对藤本植物园林应用提供理论参考依据。

  7. Ordoño Sisnández, autor de la Historia legionensis (llamada silensis. Notas histórico-filológicas sobre un ego fundador

    Georges Martin


    Full Text Available Se adelanta aquí la hipótesis de que Ordoño Sisnández, canónigo de San Isidoro de León entre 1110 y 1133, fue hijo de Sisnando, conde de Coimbra entre 1064 y 1091, y autor de la Historia legionensis (llamada silensis. Los documentos, bastante numerosos, en los que aparece no dan parte de ninguna filiación, ni, por supuesto, de ninguna autoría. La hipótesis descansa sobre siete indicios. Cuatro de ellos, los hallo en el texto de la obra: el doble interés territorial que manifiesta el autor por Coimbra y por León –más concretamente por la iglesia de San Isidoro–; la evocación altamente elogiosa –única tocante a un noble– que hace en ella del conde Sisnando de Coimbra; el arraigo de dicha evocación en un saber de origen conimbricense; la sibilina y probablemente gratificadora mención que hace de su padre al traer a cuenta una apreciación histórica de Almanzor que podía desconcertar a sus lectores u oyentes. Los tres indicios restantes los encuentro en la documentación de los reinados de Urraca y Alfonso VII: la existencia en San Isidoro de León, lugar donde probablemente se compuso la Historia, de un tal Ordoño Sisnández cuyo patronímico y cuya fecha de muerte (1150 pueden autorizar la idea de que fuera hijo del conde Sisnando; la enigmática preeminencia de la que gozó dicho personaje entre las comunidades canonicales a las que perteneció pese a que no disfrutara de ninguna dignidad eclesiástica; las confirmaciones que hizo bajo su solo nombre entre próceres de la más alta nobleza.On formule ici l’hypothèse qu’Ordoño Sisnández, chanoine de Saint-Isidore de León entre 1110 et 1133, fut le fils de Sisnando, comte de Coïmbre entre 1064 et 1091, et l’auteur de l’Historia legionensis (dite silensis. Les documents assez nombreux où apparaît cet homme ne font état ni de son père ni d’aucune oeuvre dont il serait l’auteur. L’hypothèse repose néanmoins sur sept indices. Quatre d’entre eux se

  8. Sedimentary facies analysis of Yanchang Formation 2th in LFP block,Erdos Basin%鄂尔多斯盆地 LFP区块长2段沉积相研究

    叶亚坤; 苏海伦; 薛永康; 李阳阳


    储层的沉积相研究通常是油气藏勘探开发过程中一项十分重要的任务,它控制着储集砂体的成因类型及宏观分布。在岩芯观察的基础上,结合综合录井资料和野外露头剖面信息,运用沉积学、沉积构造、剖面结构、古生物及测井相等划分沉积相的标志,对研究区内钻井进行单井沉积相划分,对不同钻井之间的沉积相进行综合比对,结果认为LEP区块长2段主要从三角洲前缘高建设的水下分流河道骨架砂体沉积为主。%Reservoir sedimentary facies study is usually an important reservoir exploration and development task,it con-trols the genetic types and macro distribution of reservoir sand bodies. On the basis of core observation,according to the out-crop section information and comprehensive logging data,we use of sedimentology,paleontology,sedimentary structure,pro-file structure and logging equal dividing sedimentary facies marks,drilling in the area of study on single well sedimentary facies classification,on this basis to make a comprehensive comparison of sedimentary facies,between different drilling and exposes in the LFP blocks long 2 characteristics of sedimentary facies and sedimentary environment changes.

  9. Analysis of Milankovitch Cycles of Yanchang Formation in Jing′an Oilfield%靖安油田延长组米兰柯维奇沉积旋回分析

    李斌; 孟自芳; 李相博; 卢红选; 郑民



  10. Characteristics of flora from the Datong Formation in Ningwu coalfield, Shanxi

    Chang Jianglin; Gao Qiang [Shanxi Institute of Coal Geology (China)


    41 species assigned to 21 genus of plant remains from the Datong Formation in Ningwu Coalfield, Shanxi, are recognized by the authors. In this paper, the characteristics and geological age are discussed in detail. The flora is composed mainly of Filicinae and Ginkgophytes. Equistales and Coniferales are the second largest, and Cycadophyta is rarely found. It belong to Coniopteris-phoenicopsis flora is well-developed in North China and could be compared with the floras of the Datong Formation in Datong Coal-field, the Mentougou Group in West-Hills of Beijing, the Yanan Formation in Ordos Basin and the Dameigou Formation in Qinghai. The geological age of this flora may be assigned to the Middle Jurassic. 14 refs., 1 tab., 14 plates.

  11. 鄂尔多斯盆地致密油水平井体积压裂优化设计%Optimization design for volume fracturing of horizontal wells in tight oil reservoir of Ordos Basin

    白晓虎; 齐银; 陆红军; 段鹏辉; 顾燕凌; 吴甫让


    鄂尔多斯盆地长7致密油储层致密、油藏低压。储层天然微裂缝发育程度和岩石脆性评价表明,盆地致密油储层物性对水平井分段体积压裂具有良好的适应性。以提高水平井多段压裂井网形式和布缝的匹配性为目的,优化了与注采井网相适配的施工参数,结果表明,实现体积压裂的排量为4~8 m3/min,单段砂量40~80 m3,入地液量300~700 m3,并形成了“低黏液体造缝、高黏液体携砂、组合粒径支撑剂、不同排量注入”的混合压裂设计模式。矿场井下微地震监测对比了体积压裂与常规压裂对裂缝扩展形态的影响,结果显示致密储层采用体积压裂的改造体积和复杂指数是常规压裂的2倍左右,且与井网适配性良好。通过开展致密油开发矿场先导性试验,水平井单井初期产量达到8~10 t/d,第1年累计产油量达2000 t左右,且无裂缝性见水井,证明对于鄂尔多斯盆地的致密油开发,采用水平井五点井网+混合水体积压裂可以获得较高的单井产量和良好的开发效益。该项技术对其他油田的非常规储层开发有一定的借鉴意义。%Chang 7 tight oil reservoir of Ordos Basin features tight and low-pressure reservoir. It is shown from natural microfracture development degree and rock brittleness assessment of the reservoir that, properties of tight oil reservoir of the basin are highly adaptable to segmented volume fracturing of horizontal wells. The construction parameters which match with lfood pattern are optimized for the purpose of improving compatibility between multi-segment fracturing pattern form and fracture distribution of horizontal wells, and results indicate that volume fracturing is realized by displacement between 4 m3/min to 8m3/min, single-segment sand amount between 40 m3 to 80 m3, and buried liquid amount between 300 m3 to 700 m3. The mixed fracturing design mode of fracture formation by low

  12. New method for prediction of shale gas content in continental shale formation using well logs

    Li, Sheng-Jie; Cui, Zhe; Jiang, Zhen-Xue; Shao, Yu; Liao, Wei; Li, Li


    Shale needs to contain a sufficient amount of gas to make it viable for exploitation. The continental heterogeneous shale formation in the Yan-chang (YC) area is investigated by firstly measuring the shale gas content in a laboratory and then investigating use of a theoretical prediction model. Key factors controlling the shale gas content are determined, and a prediction model for free gas content is established according to the equation of gas state and a new petrophysical volume model. Application of the Langmuir volume constant and pressure constant obtained from results of adsorption isotherms is found to be limited because these constants are greatly affected by experimental temperature and pressures. Therefore, using measurements of adsorption isotherms and thermodynamic theory, the influence of temperature, total organic carbon (TOC), and mineralogy on Langmuir volume constants and pressure constants are investigated in detail. A prediction model for the Langmuir pressure constant with a correction of temperatures is then established, and a prediction model for the Langmuir volume constant with correction of temperature, TOC, and quartz contents is also proposed. Using these corrected Langmuir constants, application of the Langmuir model determined using experimental adsorption isotherms is extrapolated to reservoir temperature, pressure, and lithological conditions, and a method for the prediction of shale gas content using well logs is established. Finally, this method is successfully applied to predict the shale gas content of the continental shale formation in the YC area, and practical application is shown to deliver good results with high precision.

  13. 鄂尔多斯盆地南缘奥陶系露头沥青地球化学特征与意义%Geochemical characteristics and significance of bitumen of Ordovician outcrops at the southern margin of Ordos Basin

    金晓辉; 孙润轩; 陈霞; 孙宜朴; 张军涛; 李淑筠


    鄂尔多斯盆地南缘露头沥青赋存于下奥陶统亮甲山组灰岩裂缝中,裂缝近垂直于层面,沥青高约75 m,宽约1~44 cm,下宽上窄。其沥青质的碳同位素为-28‰,沥青等效反射率分布在1.829%~1.965%之间;沥青和上奥陶统背锅山组烃源岩均具有较低的Pr/Ph值、较高的C24四环萜烷的生物标志物,沥青的C29甾烷优势和低伽马蜡烷指数可能揭示其成烃母质形成于微咸水的低等海洋浮游生物的环境。沥青和背锅山组烃源岩规则甾烷组成均有“V”型特征,C24四环萜烷/C26三环萜烷、Tm/Ts值萜烷生物标志物参数值接近,表示他们具有亲缘关系。南缘奥陶系沥青地球化学特征及成因研究,对评价南缘下古生界碳酸盐岩的勘探潜力具有重要的理论和生产价值。%Outcrop bitumen occurs in the limestone cracks in the Lower Ordovician Liangjiashan Formation at the southern margin of Ordos Basin. The cracks are nearly vertical. The bitumen zone is about 75 m high and 1-44 cm wide, and is wide at the bottom and narrow on the top. The carbon isotope value of the bitumen is-28‰. Equivalent bitumen vitrinite reflectance ranges from 1.829%-1.965%. The bitumen and the source rocks in the Upper Ordovician Beiguoshan Formation have low Pr/Ph values and high C24 tetracyclic terpane biomarker concentrations. Bitumen sam⁃ples with C29 sterane predominance and low gammacerane index reveal that hydrocarbon parent materials were formed in a low⁃brackish water environment from marine plankton. The composition of steroids is“V” type, and the biomar⁃kers such as C24 tetracyclic terpanes/C26 tricyclic terpanes and Tm/Ts are similar, indicating a genetic relationship. The geochemical characteristics and significance of bitumen of the Ordovician outcrops at the southern margin of Ordos Basin have helpful for the evaluation of the Lower Paleozoic carbonate source rocks.

  14. Identifying the origin and geochemical evolution of groundwater using hydrochemistry and stable isotopes in Subei Lake Basin, Ordos energy base, Northwestern China

    F. Liu


    Full Text Available A hydrochemical and isotopic study was conducted in Subei Lake Basin, northwestern China, to identify the origin and geochemical evolution of groundwater. Water samples were collected, major ions and stable isotopes (δ18O, δ D were analyzed. In terms of hydrogeological conditions in study area, groundwater can be classified into three types: the Quaternary groundwater, the shallow Cretaceous groundwater, the deep Cretaceous groundwater. Piper diagram and correlation analysis were used to reveal the hydrochemical characteristics of water resources. The dominant water type of lake water was Na-Cl type, which was controlled by strong evaporation and recharge from overland flow and groundwater; the predominant hydrochemical types for groundwater were Ca-HCO3, Na-HCO3, and mixed Ca · Na · Mg-HCO3 types, the groundwater chemistry is mainly controlled by dissolution/precipitation of anhydrite, gypsum, halite and calcite. The dedolomitization and cation exchange are also important factors. Rock weathering is confirmed to play a leading role in the mechanisms responsible for the chemical compositions of groundwater. The stable isotopic values of oxygen and hydrogen in groundwater are close to the local meteoric water line, showing that groundwater is of meteoric origin. The deep Cretaceous groundwater is depleted in heavy isotopes, compared to shallow Cretaceous groundwater. The hydrogen and oxygen isotopes signatures in deep Cretaceous groundwater may show a paleorecharge effect that the deep Cretaceous groundwater was recharged during a geologic period when the climate was wetter and colder than today. Due to strong evaporation effect and dry climatic conditions, heavy isotopes are more enriched in lake water than groundwater. The hydrochemical and isotopic information of utmost importance has been provided to decision-makers by the present study so that a sustainable water resources management policy could be designed for the Ordos energy base.

  15. Origins of natural gas and the main controlling factors of gas accumulation in the Middle Ordovician assemblages in Jingxi area, Ordos Basin

    Xinshe Liu


    Full Text Available During the progressive exploration of the Jingbian Gas Field in the Ordos Basin, multiple gas-bearing regions have been discovered in the dolomite reservoirs in the Middle Ordovician assemblages of Lower Paleozoic in Jingxi area, but these gas-bearing regions and intervals are significantly different in terms of gas enrichment degrees. So far, however, the reasons for the difference have not been figured out. In this paper, the origin and source of natural gas in the Middle Ordovician assemblages in Jingxi area was investigated on the basis of geochemical data (e.g. natural gas composition and carbon isotope, and then the main factors controlling the gas accumulation were analyzed. It is shown that the natural gas in the Middle Ordovician assemblages in the Middle Ordovician assemblages in Jingxi area is similar to that in the Upper Ordovician assemblages and Upper Paleozoic reservoir in terms of genesis and sources, and they are mainly the Upper Paleozoic coaliferous gas with some oil-derived gas. Under the influence of hydrocarbon generation center of coal source rocks and the source–rock–reservoir contact relationship, the proportion of coaliferous gas increases areally from the north to the south and vertically from Ma55 sub-member of the Lower Ordovician Majiagou Fm. It is concluded that the natural gas enrichment degree is controlled by the gas charging capacity at the hydrocarbon-supplying windows. Second, the vertical migration and distribution of natural gas is dominated by the differences of Ma55−Ma510 transport pathways. And third, the lateral migration direction of natural gas and the range of gas accumulation are controlled by the superimposition relationship between structures and reservoirs.

  16. Characteristics of Majiagou Palaeokarstic Reservoir of Ordovician in Daniudi Gas Field of Ordos Basin%鄂尔多斯盆地大牛地气田马家沟组古岩溶储集层特征

    赵淑平; 王起琮


    The petrographic and geochemical characteristics of carbonate reservoirs of the Ordovician in Daniudi gas field in Ordos basin are presented in this paper,including the micro-characteristics of the palaeokarstic reservoir by using microscopic optical method,the diagenetic properties of the reservoir by using isotopic geochemical methods and the palaeokarstic landform restoration by using residual thickness and impression approaches and its control of the reservoir development.The palaeokarstic reservoir of Majiagou formation is dominated by karst breccias and micritic dolomite,with developed caves,fractures and intergranular pores,and the carbon-oxygen isotope is negative,the 87Sr/86Sr is higher,obviously.The palaeokarstic landforms can be divided into 3 types,of which the karstic ramp underwent strong karstification,being the favorable domain of developed reservoirs;the bauxites above the karstic ramp are effective cap rocks with well sealing ability,being the favorable area for gas accumulation.The studied results show that stable isotope geochemistry is an effective tool to study karstification of carbonate reservoirs,the dissolution and dolomization are the key factors controlling the palaeokarstic reservoir development.%探讨了鄂尔多斯盆地大牛地气田奥陶系碳酸盐岩储集层的岩石学及地球化学特征。应用显微光学方法分析了岩溶储集层的微观特征,应用同位素地球化学方法研究了储集层的成岩作用特征,应用残余厚度法和印模法开展了古岩溶地貌恢复及其对储集层发育的控制作用研究。大牛地气田奥陶系马家沟组古岩溶储集层以岩溶角砾岩和泥粉晶白云岩为主,发育溶蚀孔、洞、缝以及晶间孔隙,储集层碳、氧稳定同位素明显偏负,87Sr/86Sr值明显偏高。岩溶地貌划分为3种地貌单元,其中岩溶斜坡的溶蚀作用强烈,是储集层发育的有利部位,其上覆铝土岩为有效盖层,封盖能力较强,是天然气

  17. Optimization and Innovation of Surface Engineering Gathering and Transporta-tion Technology on Yanchang Gas Field YQ2-Y128 Well Area%延长气田延气2-延128井区地面集输工艺的优化创新

    张春威; 张书勤; 韩建红; 梁裕如; 薛红波


    Pilot test area of YanChang gas field YQ2-Y128 well area had some problems af-ter completion.Pressure of wellhead equipments and ground gas gathering pipelines were too high and security risk was existed. It was easy to generate hydrate and methanol injection amount was large. The gathering radius was too small and gas gathering station and perma-nent occupancy of arable land was too much. Aiming to above problems, optimization and innovation of surface engineering gathering and transportation technology had been done. The new system is more suitable for YanChang gas field after optimization,and the gas radius increased by 1.4 times, the number of gas wells into single gas station increased 2.3 times, 8 gas gathering stations and about 15% of land area were reduced, more than 20% of the oper-ating cost was cut down, the length of the single well gas pipeline is reduced by 50%, the pipeline engineering quantity is reduced by 54.6%, the single well injection methanol re-duced 50%,the efficiency of single injection methanol pump increased by about 150%,proj-ect investment reduced 0.28 billion yuan and single well ground engineering investment was reduced by 42.3%. In 2014,the project successfully put into production. The system runs safely and smoothly at present.%延长气田延气2-延128井区先导试验区建成投产后存在井口设备和地面集输管线承压高、安全风险大;容易生成水合物、注醇量大;集气半径小、单个集气站纳入井数少、站点多和永久占地多等问题。针对存在问题,对续建的一期地面集输工艺进行了优化和创新,提高了集输工艺技术的适用性。优化后,集输站集气半径增加1.4倍,单个集气站纳入井数增加2.3倍,集气站数量减少8座,集气站减少用地面积约15%,运行费用降低20%以上;平均单井采气管线长度减少50%以上,管线工程量减少54.6%;单井注醇量减少50%,单台注醇泵注醇效率提高约150%

  18. On Research of Private Lending System and its Supervision's Countermeasure in Ordos%鄂尔多斯地区民间借贷及其监管对策研究



    鄂尔多斯地区民间借贷在近年来发展速度与规模非常快,对地区经济成长与发展起到积极推动作用的同时,其带来的一系列问题也成为人们关注的热点。游离于监管体制外的大量民间资金的存在也严重影响了国家宏观调控政策实施的效果,对地区社会经济稳定和金融安全带来巨大隐患,在分析鄂尔多斯民间借贷特点和形成原因的基础上,针对性提出了推动鄂尔多斯金融稳定健康发展的对策与措施。%In recent years, Ordos’area folk loan development is rapid, in regional economic growth and development play a posi-tive role at the same time, it brings a series of problems have become the focus of attention. Survey found that Ordos’area folk loan ef-fectively support the development of small and medium businesses in Ordos, But at the same time, free from outside of the regulation system of the existence of folk capital also seriously affected the national macroeconomic regulation and control policy implementation effect, on the regional social and economic stability and financial security bring great hidden danger. Based on the reasonable definition of folk loan category and its produce development theory is introduced on the basis of the current Ordos’area folk lending conditions and characteristics, and analysis the cause of Ordos folk lending, and based on this, the comprehensive evaluation of the Ordos’folk loan of the positive and negative influence, put forward aims to promote the healthy development of the Ordos’financial stability, the coun-termeasures and measures. This article will put forward a lot of ways to solve the problems and prompt the economic development of Ordos.

  19. Provenance analysis of sandstone of the Upper Carboniferous to Middle Permian in Ordos Basin%鄂尔多斯盆地上石炭统-中二叠统砂岩物源分析

    陈全红; 李文厚; 刘昊伟; 李克永; 庞军刚; 郭艳琴; 袁珍


    Based on comprehensive study of regional geology, stratigraphic contact relations, sandstone fragment components, heavy mineral and trace elements, the Upper Carboniferous to Middle Permian provenance area for the north Ordos Basin mainly come from recycling orogeny area, and can be divided into three provenance areas that are Wuhai-Yinchuan, Hangjinqi-Dongsheng, Zhungeer-Fugu. But affected by variation provenance and bounded by Hangjinqi-Dongsheng, the distribution of quartz sandstone of Ordos Basin that was derived from Alashan ancient land has obvious west-east trending divisional feature and is mainly distributed in west Ordos Basin, but lithic sandstone that came from Yin Mountains mainly distributed in east Ordos Basin. South and southwest trending source sandstone that came from steady tectonic area and recycling orogeny area are strongly related to the evolution of Qin-Qi orogenic belt, and has the duplex characteristic of activity and stabilization. So the south provenance can be divided into three provenance areas that are Haiyuan and Tongxin-Zhongwei, Pingliang-Guyuan and Huaixian, Yaoxian-Yijun and Fuxian. The catchment area of south and north provenance with NWW trending shoestring extension is located in Huanxian-Fuxian-Xianning area, and the catchment area gradually transfers to south Ordos Basin during Shanxi to He-8 period. Until He-8 period, the west provenance began to supply coarse clastic sediments. In Liuyehe Basin, Zhouzhi, as the outer margin of Ordos Basin, which is the intermontane basin of Qinling orogenic belt and has continuous transitional relationship between them, the Upper Carboniferous to Middle Permian sandstone came from recycling orogeny area and continental blocks.%对区域地质、地层接触关系、砂岩组分、重矿物及微量元素等的综合分析与研究结果表明,鄂尔多斯盆地北部上石炭统-中二叠统砂岩的物源区主要为再旋回造山带物源区,并可划分出乌海-银川、杭锦

  20. 内蒙古西部自然保护区生态环境保护可持续发展 ——以西鄂尔多斯保护区为例%Ecologocal Environment Protection of Regions of Natural Reserves of Sustainable Development in the West of Inner Mongolia ——for Example Wesxt Ordos



    It's very difficult to protect ecological environment of regions of natural protection area in the west of Inner Mongolia because of bad natural conditions, for instance, the West Ordos. However, human actions urban and regional economic development are direct reason to give rise to ecological environment worsening in the West Ordos region of natural reserves. Combined with more field exploring material, this paper analysis the major reasons that cause ecological environment worsening due to the urban and regional economic development in the recent two or three decades:   (1) Coal pit and ash kiln destroyed surface vegetation.   (2) “Three-waste” material of industry seriously polluted precious, rare and endangered plants.   (3) Over-grazing sped grass deterioration in the region of reserver.   (4) Traffic damaged ecological environment. It puts forward some effective ways of sustainable development in the ecological environment protection in the West Ordos.%恶劣的自然地理环境条件使得内蒙古西部自然保护区生态环境保护十分困难,而人类活动,特别是地区经济、城市工业等的发展又成为目前造成保护区生态环境恶化的直接原因,西鄂尔多斯自然保护区就是一典型例证。

  1. On the Peritidal Carbonate Cyclicity and Its Origin of the Ordovician M5 Section in Central Ordos Basin%陕甘宁盆地中部马五1潮缘碳酸盐岩沉积旋回及其成因探讨

    孟万斌; 张锦泉


    陕甘宁盆地中部马五1段由多个向上变浅的潮缘碳酸盐岩沉积序列重复叠置组成,并可分为十三种沉积-成岩微相和六个沉积相带。这种沉积序列的韵律性重复叠置的形成方式为潮缘进积楔的简单退覆和阶段式退覆,其形成机制为自旋回。%The term peritidal coined by Folk is a useful general name for the spectrum of nearshore and shoreline deposi-tional environments and facies. Ancient peritidal carbonate lithofacies are characteristically organized stratigraphi-cally into meter - to decameter - thick, shallowing - upward successions; their vertical stacking is a valuablerecord of the dynamics of carbonate platform development. There are currently three models used to explain how ashallowing-upward succession forms, 1) as a prograding wedge, 2) as a simultaneously aggrading sheet or, 3) asa mosaic of tidal flat islands. A prograding wedge is generated by the tidal flats prograding in two styles, simple of-flap and staggered offiap. A simultaneously aggrading sheet accretes vertically to sea level and the whole platformbecomes sequentially intertidal and then supratidal. Tidal flat islands nucleate and accrete by aggradation andprogradation and shift in response to hydrographic forces. Much discussion exists currently as to what causes therhythmic stacking into thick stratigraphic packages of ancient shallowing - upward successions. Two possiblemechanisms are suggested, i, e., allocyclic and autocyclic mechanisms. The driving force behind the autocyclicity isthe dynamics of sedimentation on the platform, while the allocyclicity emphasizes the factors of subsidence and eu-stacy that cause relative sea level change. However, the two mechanisms are not necessarily mutually exclusive.The Ordovician M5 section in central Ordos basin consists of a rhythmic repetition of several shallowing- upwardperitidal carbonate successions deposited in epeiric sea. Based on the sedimentary structure and

  2. 鄂尔多斯盆地姬塬地区长8段孔隙度演化定量模拟%Quantitative Simulation on Porosity Evolution of Chang-8 Section in Jiyuan Area of Ordos Basin

    唐俊; 庞国印; 唐丽; 马晓峰; 王琪


    Based on the analysis of characteristics and major controlling factors of Chang-8 section sandstone reservoir in Jiyuan area of Ordos Basin and the study on corresponding stratigraphic and diagenetic history, combined with petroleum geology theory and mathematical statistics method, porosity evolution was divided into two processes including the decrease and increase of the porosities under the condition of the restriction of present porosity, and a model for the porosity evolution of Chang-8 section sandstone reservoir in the research area was built. Porosity varied with the depth of burial and geological time from the initial burial to the present in the model. The results showed that the model with quantitative porosity evolution was a piecewise function with four sections. Mechanical compaction stage was a model with the decrease of porosity, which was a continuous function with the independent variable of burial depth; compaction and cementation stage was a model with the decrease of porosity, which was a continuous function with the variables of geological time and burial depth; the secondary porosity increase was caused by the dissolution of acid fluid within a temperature range of 70℃ -110℃ , so that dissolution stage was a model with the increase of porosity, which was a composite function of depth and burial time; after the dissolution stage, formation porosity was in compaction and maintenance stage, which was a model with the decrease of porosity, and the model was a superimposed composite function of depth, burial time and the porosity increase amount. Finally, taking one well in the research area as an example, it was verified that the model with quantitative porosity evolution was consistent with actual geological condition, and could be applied to calculate the porosity of any strata.%在对鄂尔多斯盆地姬塬地区长8段砂岩储层特征、主控因素及地层埋藏史和成岩史研究的基础上,结合石油地质理论,应用数理

  3. Characteristics and Mechanism of Permian Shanxi Tight Reservoir of Changbei Gas Field,Ordos Basin%鄂尔多斯盆地长北气田山西组二段低孔低渗储层特征及形成机理

    孙海涛; 钟大康; 张湘宁; 柳慧林


    Changbei gas field is located in Yishan Slope of the northern center of the Ordos Basin,China.The main pay zone reservoir is Upper Paleozoic Lower Permian Shanxi P1S2 quartz arenite,which deposited in distributary channel of delta plain.The reservoir is low porosity low permeability tight reservoir with average porosity of 5.2% and average permeability of 0.7×10-3 μm2 in a current depth of 2 700~2 950 m.Integrated study on depositional environment,lithology,diagenesis and tectonic background has been conducted.The reasons cause this low porosity low permeability tight reservoir features are considered as the following two factors.(1) On one hand,the reservoir was deposited in a coaly bearing acid environment of deltaic distributary channel,the original pore water is acid water with non saturated calcium carbonate,which can not form earlier cementation within the sandstone reservoir.However,compaction has significantly reduce the original pore and pore volume.On the other hand,this acid diagenesis environment cause large amounts of secondary quartz cementation fill the pores left out during compaction of sandstone reservoir.This is the main reasons cause the low porosity low permeability tight reservoir features in the region.Observation from thin section indicate that calcium carbonate cementation is not developed in the pore of sandstone reservoir especially in the earlier stage,the average component of calcium carbonate cementation is 1%~3%,authigenic kaolinite cementation is well developed with an average component of 7%~10%,illite segmentation is also less developed 3%,secondary quartz cementation well develop,mostly reach Ⅱ—Ⅲ level with an average component of 5%~10%,some layer can reach 10%~18% and maximum is 23%,this phenomenon indicated the acid diagenesis environment of P1S2 quartz arenite reservoir in Changbei gas field.(2) Tectonic study indicated that Changbei gas field is located in Ordos Basin tectonically stable at the time

  4. 鄂尔多斯蒙古族可持续利用有毒木本植物传统文化%Mongolian Traditional Sustainable Utilization Knowledge of Poisonous Ligneous Plants in the Ordos Grassland, China



    Traditional culture that the effective and sustainable utilization of poisonous plants is one characteristics of Mongolian ecological culture. Applying the methods like ethnoecology, plant taxonomy and cultural anthropology to analyze how Mongolian utilizes poisonous ligneous plants, and discussing about active effects of Mongolian traditional culture of utilizing poisonous plants on biodiversity conservation to grassland ecosystem in the Ordos plateau. The research to plant taxonomy and cultural anthropology found that those poisonous plants, such as Caryopteris mongholi-ca, Ephedra sinica, Juniperus sabina, Oxytropis aciphylla and Primus mongolica, can be used detoxification culture, eating culture, beauty culture and curing skin diseases. Therein, Ephedra sinica plays an important role on Mongolian nomadic economy and culture. Ordos Mongolian traditional culture of utilizing poisonous plants is distinguished from others' which are in other areas on Mongolian Plateau and reflects unique regional cultural character. Mongolian traditional managing culture of utilizing plants ground parts, which can diminish, even avoid desertification. Also it is consistent with ecological law and is one of elements which can ensure stable and sustainable development and biodiversity conservation of the Ordos grassland ecosystem.%有效地、可持续利用有毒植物的传统文化是蒙古族生态文化的一个特色.运用民族生态学、植物分类学和文化人类学的研究方法,分析有毒木本植物可持续利用蒙古族传统文化,探讨了蒙古族有毒植物传统管理文化对鄂尔多斯草原生物多样性保育的积极意义.植物分类学和文化人类学的研究发现,蒙古莸(Caryopteris mongholica)、草麻黄(Ephedra sinica)、沙地柏(Juniperus sabina)、刺叶柄棘豆(Oxytropis aciphylla)和蒙古扁桃(Prunus mongolica)等有毒木本植物为鄂尔多斯蒙古族重要的解毒、食用、美容和治疗皮肤病植物.鄂尔多斯

  5. 鄂尔多斯蒙古族5项舌运动类型的人类学研究%The Anthropological Studies of Five Tongue Moving Types of Ordos Mongols

    刘璐; 李咏兰


    2014年9月对鄂尔多斯市鄂托克旗蒙古族中学共224例蒙古族学生(男性92例,女性132例)的5项群体遗传学指标(卷舌、叠舌、翻舌、尖舌、三叶舌)进行了研究.结果发现:1)鄂尔多斯蒙古族人的卷舌、叠舌、翻舌、尖舌、三叶舌出现率分别为53.57%、6.70%、28.57%、56.25%、2.68%.卷舌、尖舌率性别间差异具有统计学意义,叠舌、翻舌、三叶舌率性别间差异无统计学意义.2)与中国北方族群比较,鄂尔多斯蒙古族卷舌、尖舌、三叶舌率偏低,叠舌、翻舌率属中等水平.3)聚类分析结果显示,鄂尔多斯蒙古族与阿拉善蒙古族、乌拉特蒙古族关系较近.%In September 2014 researched the index of population genetics of 5 tongue moving types( tongue rolling, tongue folding,tongue twisting,pointed tongue and clover-leaf tongue)of 224 Mongolian students( male 92,female 132)in Etoke Banner of Inner Mongolia. Results showed that:(1)The frequencies of tongue rolling,tongue folding, tongue twisting,pointed tongue and clover-leaf tongue were 53. 57%,6. 70%,28. 57%,56. 25% and 2. 68%,re-spectively. Significant sexual difference were found in the frequency of tongue rolling and pointed tongue(P0. 05).(2)Compared with other nationalities,the Ordos Mongolian had lower frequen-cies of rolling tongue,pointed tongue,clover-leaf tongue,and the frequencies of tongue folding,tongue twisting were in the medium level.(3)The results of cluster analysis showed that Ordos Mongolian was close to that of Alxa Mon-golian,and Urad Mongolian.

  6. Analysis of landscape pattern on the urban green space in Kangbashi New Area of Ordos city%鄂尔多斯市康巴什新区城市绿地景观现状分析

    李晓波; 潮洛濛; 王光明


    In this paper, the current pattern of urban green space in Kangbashi of Ordos city was studied through the analysis of the feature of area and landscape of a variety of green space based on the QuickBird remote sensing data in 2009. The result showed that the green space area was of 10.18 km2, and city green rate reached to 29.34% in Kang Bashi New Area of Ordos city. The park green space area per capita was large, but the overall green space rate was lower than its goal of planning. Landscape type was relatively complete and the distribution was uniform. The park green space and the path green space were corresponding to the matrix and corridor of urban green space in the studied area. The residential green space had high degree of fragmentation, while the protective green space had high degree of edge separation. The shannon diversity index, the Shannon evenness index and the separation index of urban green space landscape were 1.73,0.75 and 5.43, respectively. On the basis of this, the related proposals for the city future development were advanced.%利用2009年QuickBird遥感影像数据,通过对各种绿地面积及景观特征的研究,对鄂尔多斯市康巴什新区绿地景观现状进行分析.结果表明,鄂尔多斯市康巴什新区绿地面积为10.18 km2,城市绿地率29.34%.人均公园绿地面积很高,但整体绿化率距其规划目标还有一定的差距,绿地景观类型较齐全,且分布较均匀.公园绿地和道路绿地分别为研究区城市绿地景观的基底和廊道.居住绿地的破碎化程度较高,防护绿地边缘割裂的程度较高.城市绿地景观的Shannon多样性指数、Shannon均匀度指数和分离度指数分别为1.73、0.75和5.43.在此基础上,对城市今后发展提出相关建议.

  7. 鄂尔多斯盆地吴起地区侏罗纪早中期河流沉积及油气分布%Study on fluvial deposits and oil & gas distribution of early and middle Jurassic in Wuqi area,Ordos Basin

    孟立娜; 李凤杰; 方朝刚; 李磊; 林洪


    应用现代沉积学理论,结合岩心观察描述、钻井、测井等资料,对鄂尔多斯盆地吴起地区侏罗纪早中期富县组到延安组延10、9、8期的沉积体系、岩相古地理特征及演化进行了详细研究,认为早侏罗世富县组和中侏罗世延安组延10期为深切河谷充填的辫状河沉积,延9和延8期则发育曲流河沉积.这2种河流沉积经历了有规律的继承性演化:富县组河谷充填作用最强,辫状河道砂体沉积厚度最大.延10期河谷进一步填平补齐,河谷斜坡上次级河道溯源增长、侧向侵蚀使河道变宽,漫滩分布面积减小.延9和延8期,古地形差异进一步减弱,河流转型为曲流河,河道和漫滩沉积均发育.吴起地区侏罗纪早中期河流发育辫状河和曲流河2种河流沉积模式.沉积相对富县组-延安组延8油层组油藏分布起主要控制作用,油气聚集主要受河道砂体展布控制,储层发育的河道砂体是该区今后勘探的主要目标.%On the basis of core observation,well drilling datalogging data and so on,the characteristics and evolution of the sedimentary system from Fuxian Formation to Yan10, Yan 9, Yan 8 reservoirs of Yan an Formation of early and middle Jurassic in Wuqi are-a, Ordos Basin are studied in detail using modem sedimentology theory. It is held that Fuxian Formation of early Jurassic and YanlO reservoir of middle Jurassic are dominated by deep valley filling braided fluvial deposits, and Yan 9 and Yan 8 reservoirs are dominated by meandering fluvial deposits. The two types of fluvial deposits experienced regular inherited evolution. The braided sand-body of Fuxian Formation is the thickest because of the strongest valley packing action. During YanlO period,the filling process continued,headward e-rosion was developed on the sub-valley slopes, the channel grew wider due to lateral erosion and the distribution range of flood plain reduced. During Yan 9 and Yan 8 periods, river became

  8. Optimization Techniques of Cementing of Shallow Extended Reach Horizontal Wells in Yanchang Oilfield%延长油田浅层大位移水平井固井优化技术



    固井作业是一次性工程,一旦固井质量出现问题,补救作业一般无法达到封固合格的要求,并且水平井固井存在一定的固井工艺难点,包括弯曲井段曲率大,套管不易下入;斜井段套管与井壁发生长段面积的多处接触,井斜越大,摩阻力越大;环空的严重偏心度使窄边钻井液不能有效清除;易形成集中的水带,尤其是水平井游离水易集中与井眼上方,使油气串通;且直井中常用的固井附件不能使用,需要改进或重新设计。延长油田东部的部分区域油层埋深浅、存在低压、易漏失层,该区域内的井在固井过程中易发生地层破裂、水泥浆漏失现象。这不仅使水泥浆返高不够,也对地层造成了污染,严重影响了固井质量和油水井的后续生产。%Cementing job is a one-time project,once the cementing quality problems,remedial cementing opera-tions are generally unable to meet eligibility requirements,and there is a certain level of well cementing cementing process difficulties,including the curved portion curvature,casing under difficult into;inclined casing and the bore-hole wall segments occur long segment of multiple contact area,the greater the deviation,the greater the friction re-sistance;annulus serious eccentricity so narrow mud can not effectively clear;easy to form a concentrate with water especially easy to focus on horizontal wells and above the free water borehole so that oil and gas collusion;and ver-tical wells cementing common attachment can not be used,need to be improved or redesigned. And the extension of the eastern part of the region′s oil reservoir is shallow,there is a low pressure,easy thief zone,the region in the well cementing process prone to the formation fracture,grout leakage phenomenon. This not only makes the grout is not high enough to return,but also resulted in the formation of pollution,seriously affecting the quality of cementing oil

  9. Analysis of Fracturing Network Evolution Behaviors in Random Naturally Fractured Rock Blocks

    Wang, Y.; Li, X.; Zhang, B.


    Shale gas has been discovered in the Upper Triassic Yanchang Formation, Ordos Basin, China. Due to the weak tectonic activities in the shale plays, core observations indicate abundant random non-tectonic micro-fractures in the producing shales. The role of micro-fractures in hydraulic fracturing for shale gas development is currently poorly understood yet potentially critical. In a series of scaled true triaxial laboratory experiments, we investigate the interaction of propagating fracturing network with natural fractures. The influence of dominating factors was studied and analyzed, with an emphasis on non-tectonic fracture density, injection rate, and stress ratio. A new index of P-SRV is proposed to evaluate the fracturing effectiveness. From the test results, three types of fracturing network geometry of radial random net-fractures, partly vertical fracture with random branches, and vertical main fracture with multiple branches were observed. It is suggested from qualitative and quantitative analysis that great micro-fracture density and injection rate tend to maximum the fracturing network; however, it tends to decrease the fracturing network with the increase in horizontal stress ratio. The function fitting results further proved that the injection rate has the most obvious influence on fracturing effectiveness.

  10. A study on the influence of introducing the community concept to county settlement system planning——The case of the urban-rural integration planning in Yan'an city Yanchang county%社区概念引入对县域居民点体系规划影响研究——以延安市延长县城乡一体化规划为例

    刘冬; 李志民; 王欣


    基于延安市延长县城乡居民点体系现状特征的定量化与定型化分析与梳理,通过“社区”概念的引入,从空间布局、规模、结构及规划方法四个方面,构建县域城乡居民点的框架体系,以为解决城市居民点面临的人口过度膨胀、用地紧张、交通拥挤以及削弱农村居民点出现的空心村与空巢化、重复建设与无效建设、基础设施与公共服务设施配套落后等问题,提供可以借鉴的规划范式,并为构建具有陕北地域特色的城乡居民点体系提供参考.%Based on the quantitative and stereotypical analysis and comb of urban-rural settlement system characteristics in Yanchang county, the urban-rural residence is reconstructed with its space layout, scale, structure and planning method by introducing the "community". The study provided the planning paradigms to solve the over population expansion, land tension, the traffic congestion of the urban residential areas and weaken the hollow village, empty nest, repetitive construction, invalid construction, infrastructure, public service facilities in the rural residential areas, It also, provided a reference to the construction of urban-rural residential areas with geographical features in Northern Shaanxi.

  11. Progress of Paleozoic coal-derived gas exploration in Ordos Basin, West China%鄂尔多斯盆地古生界煤成气勘探进展

    杨华; 刘新社


    Based on practices of gas exploration in the Ordos Basin, this paper analyzes the controlling factors of large-scale accumulation conditions and distribution characteristics of coal-derived gas, and concludes the exploration progress of coal-derived gas according to the present exploration situations. There are 5.24×1012 m3 proven coal-derived gas reserves in the Ordos Basin. Twelve coal-derived gas fields have been found, mainly distributed in the Upper Paleozoic Carboniferous-Permian clastic rocks and Lower Paleozoic Ordovician marine carbonate reservoirs. Tight sandstone gas reservoirs are developed in the Upper Paleozoic. The widely covered hydrocarbon source of coal stacks each other with large-scale sandstone reservoirs, the reservoirs tightened firstly and natural gas accumulated later, and natural gas migrated shortly and accumulated in a large area. The Sulige large gas field has been found with proven coal-derived gas reserves of 3.49×1012 m3, and two large-scale reserve replacements have been determined in the eastern part of the basin and the Longdong area. Marine carbonate gas pools are developed in the Lower Paleozoic. The gas generated from the overlying coal source rocks migrated downward and accumulated in the Ordovician weathering crust karst and dolomite reservoirs. The Jingbian gas field has been found with proven coal-derived gas reserves of 7 000×108 m3, meanwhile, several gas-rich regions have also been found.%基于鄂尔多斯盆地天然气勘探实践,根据煤成气勘探现状,分析煤成气成藏控制因素,总结煤成气勘探进展。鄂尔多斯盆地已探明煤成气地质储量5.24×1012 m3,发现煤成气气田12个,主要分布于上古生界石炭-二叠系碎屑岩和下古生界奥陶系碳酸盐岩储集层中。上古生界形成致密砂岩气藏,广覆式生烃的煤系烃源岩和大面积分布的砂岩储集层相互叠置,储集层先致密后成藏,天然气近距离运移、大面积成藏,

  12. Exploitation Contradictions Concerning Multi-Energy Resources among Coal, Gas, Oil, and Uranium: A Case Study in the Ordos Basin (Western North China Craton and Southern Side of Yinshan Mountains

    Xiaowei Feng


    Full Text Available The particular “rich coal, meager oil, and deficient gas” energy structure of China determines its high degree of dependence on coal resources. After over 100 years of high-intensity mining activities in Northeast China, East Region, and the Southern Region, coal mining in these areas is facing a series of serious problems, which force China’s energy exploitation map to be rewritten. New energy bases will move to the western and northern regions in the next few years. However, overlapping phenomena of multiple resources are frequently encountered. Previous exploitation mainly focused on coal mining, which destroys many mutualistic and accompanying resources, such as uranium, gas, and oil. Aiming at solving this unscientific development mode, this research presents a case study in the Ordos Basin, where uranium, coal, and gas/oil show a three-dimensional overlapping phenomenon along the vertical downward direction. The upper uranium and lower coal situation in this basin is remarkable; specifically, coal mining disturbs the overlaying aquifer, thus requiring the uranium to be leached first. The technical approach must be sufficiently reliable to avoid the leakage of radioactive elements in subsequent coal mining procedures. Hence, the unbalanced injection and extraction of uranium mining is used to completely eradicate the discharged emissions to the environment. The gas and oil are typically not extracted because of their deep occurrence strata and their overlapping phenomenon with coal seams. Use of the integrated coal and gas production method is recommended, and relevant fracturing methods to increase the gas migrating degree in the strata are also introduced. The results and recommendations in this study are applicable in some other areas with similarities.

  13. Tectonic Setting and Provenance Analysis of Late Paleozoic Sedimentary Rocks in the Ordos Basin%鄂尔多斯盆地晚古生代沉积岩源区构造背景及物源分析

    陈全红; 李文厚; 胡孝林; 李克永; 庞军刚; 郭艳琴


    The provenances of Ordos Basin and its surrounding regions, which all comes from the upper crust, are dominated by felsic rocks, which consist of ancient metamorphic rocks, such as metamorphic volcanic rocks and sedimentary rock of Archaeozoic and Proterozoic, and certain amount of granite and alkali basalt. But compositions of source and structural setting of provenances in the north and south are different. Compositions of major and rare earth elements suggest that sedimentary rocks in both north and south show some differences in area and stratum, and the changes of major element, REE and Eu anomaly are in accordance with the variation trend from oceanic island arc, continental island arc, and active continental margin to passive continental margin. Analysis of major elements indicates that the north provenance derived mainly from plate subduction zones and were related to active continental margin and passive continental margin, with minor related to the island arc of passive continental margin, and were related to tectonic setting of active continental margin and passive continental margin until middle-late Paleozoic. REE contrast analysis shows that the source for the northern basin has affinities to Archeozoic and Proterozoic metamorphotic rocks, such as granitic gneiss, diorite gneiss, adamellite, metamorphotic litharenite, phyllite, etc; that for the southern basin was deeply affected by passive continental margin source, characterized by high SiO2, low Na2 O features, and K2 O/Na2 O > 1. All these features are consistent to those (high SiO2 and K2O/Na2O>l) of rocks of Archean-Proterozoic Taihua Group, Qinling Group and Kuanping Group. Until the end of Late Paleozoic, the provenance was not affected gradually by active continental margin. Beiqinling intermontane basins characterized by rapid accumulation m langes belong to the outer margin of Ordos Basin and have continuous transitional relationship with the basin. Therefore, both show some inherited

  14. Evaluation of Upper Paleozoic Source Rocks and Favorable Region Prediction in the Southeast of Ordos Basinq%鄂尔多斯盆地东南部上古生界烃源岩评价及有利区预测

    翁凯; 李鑫; 李荣西; 张雪; 朱瑞静


    The Upper Palaeozoic hydrocarbon source rocks in the southeast of Ordos Basin are mainly composed of dark shale rocks, coal and carbonate rocks. The source rocks are a set of coal clastic sedimentary deposition of continental, marine and transitional fa-cies and are mainly concentrated in the Benxi Formation of Permian, which have wide distribution features largely controlled by sedimentary facies. The coal hydrocarbon source rock is the main supplier of natural gas, the second is dark mudstone and the third is limestone. The average content of TOC in shale hydrocarbon source rocks is higher than 2. 25% , which belongs to medium good hydrocarbon source rocks. The average content of TOC in carbonate is about 1. 69% , which belongs to good hydrocarbon source rocks. The kerogen microscopic observation and stable carbon isotopic study show that the organic component of the Upper Palaeozoic coal stratum is mainly vitnnite with d13C value being between -26. 23and -21. 23and the kerogen is mainly type III with a small number of type II , which in general is humus type - sapropelic type and the input types of source rock materials vary, which are mainly higher plants. The R0 is commonly greater than 2% , being in a high to surpassing mature evolution stage, which shows that this area in the basin is a region that can produce more. The effective combination study of natural gas migration channel and dominant migration direction shows that the favorable exploration area is distributary channel sand body region of Upper Paleozoic delta in the north of the trend of Yijun to Huanglong.%鄂尔多斯盆地东南部上古生界烃源岩主要为深色泥质岩、煤和碳酸盐岩,为1套陆相、海相及海陆过渡相沉积的含煤碎屑岩沉积,主要集中在二叠系山2—本溪组,具有广覆式的分布特征,受沉积相控制较大.煤系烃源岩是天然气最主要的供应者,第二位是暗色泥岩,其次为灰岩.泥质烃源岩的TOC平均含量大于2.25

  15. 内蒙古鄂尔多斯西北土壤水流动示踪实验及自流井群补给源讨论%Soil Water Flow Tracer Test in Northwest Ordos Basin, Inner Mongolia and Discussion on Recharge Resources of Artesian Wells

    陈建生; 杨光亮; 王婷; 何文政; 何海清; 陈茜茜


    Precipitation simulation tests prove that, maximum depth of single rainfall infiltration in northern Ordos sandy stratum is less than 1 m. Precipitation discharges to the atmosphere in the soil by evaporation. Tests confirm that only when the soil moisture content is greater than the maximum field moisture capacity, can film water on the surface of the soil particles overcome electromagnetic attraction and turn into gravitational water to infiltrate under gravity. Annual rainfall in northern Ordos is small but evaporation is large, rainfall infiltration water does not form a cumulative effect or continuous gravity water flow in the soil. Isotopic tracing analysis shows that soil water mainly comes from phreatic water. Combined with the analysis of soil moisture content and TDS, confirm that groundwater supply to the soil water through the way of film water and evaporation-condensation mode. Film water flows from high to low temperature area. For isothermal film water, it flows from thick to thin layer. Isotope analysis suggests that rivers, springs, wells, lakes, soil water in Dusitu River basin receive the same allogenic water supply. Precipitation of Ordos Basin enriches of heavier isotopes than surface water and groundwater. This does not conform to the precipitation isotope characteristics of recharge area. Groundwater watershed of Ordos Basin coincides with the basement fault zone. According to this, allogenic water supplies to the Ordos Basin through the basement fault zone and forms the artesian well group in dry areas.%降水模拟实验证明,鄂尔多斯北部沙土层单次降水入渗最大深度小于1 m,降水在土壤中受到蒸发后排泄到大气中。实验证实,只有当土壤含水率达到最大田间持水率,吸附在土颗粒表面的薄膜水才能克服电磁引力转化为重力水,在重力的作用下继续下渗。鄂尔多斯北部的年降水量小而蒸发量大,降水入渗土壤不能形成累积效应,无法形成连续下渗


    张小会; 赵重远


    由天体轨道周期变化引起的气候变化被广泛地记录在沉积地层中.自然伽马曲线很好地反映了气候变化引起的地层旋回.消除高频干扰和低频趋势以后,自然伽马曲线可以用来分析地层中的米兰科维奇旋回.对鄂尔多斯盆地陕15井中延长组按油层段进行系统分析,得出陕15井由偏心率周期引起的地层旋回厚度在9.6~18.75 m之间;地轴倾斜和气候岁差周期引起的旋回层厚度在1.18~6.82 m之间.各油层组的沉积速率变化在7.8~14.2 cm/ ka之间.

  17. The Desertification Dynamics in Ordos from 2000 to 2010 and Their Relationship with Climate Change and Human Activities%2000-2010年鄂尔多斯地区沙漠化动态及其气候变化和人类活动驱动影响的辨识

    罗君; 许端阳; 任红艳


    Ordos is one of the regions that seriously suffered from desertification in China. Carrying out the research on the desertification dynamics monitoring and its relationship with driving forces in Ordos has significance for understanding the process of desertification, making and evaluating the policies for desertification rehabilitation. In this paper, based on using the MODIS data to monitor the desertification dynamics in Ordos from 2000 to 2010, the changing trends of net primary productivity due to climate change and human activities for the lands experienced desertification reversion and expansion is analyzed, and the desertification dynamics in Ordos from 2000 to 2010 and their relationship with climate change and human activities are quantitatively assessed. It is found that the area of desertification land in Ordos did not changed obviously from 2000 to 2010, but the degree of desertification reversed significantly, and area of lands experienced desertification reversion reached 47 057 km2 (accounting for 54. 2% of the total area of Ordos), which was almost three times higher than that of desertification expansion. Climate change was the dominated factor that induced the desertification reversion from 2000 to 2010, which almost could be attributed to the increasing precipitation and the decreasing of wind speed in spring from 2000 to 2010. Also the implement of ecological protection policies, such as rangeland enclosure and grain for green and its' coupling with good climate condition, accelerated the desertification reversion. Human activities was the dominant factor that induced the desertification expansion from 2000 to 2010, which mainly attributed to the implementation of those ecological protection policies ineffective and the environment damage due to development of energy and mining industries, and the lands with desertification expansion totally induced by human activities mainly distributed in the north of Ordos.%以2000-2010年近10 a来鄂尔

  18. Population genetic diversity and differentiation of endemic species Tetraena mongolica on the Western Ordos%西鄂尔多斯特有种四合木种群遗传多样性及遗传分化研究

    张颖娟; 杨持


    Genetic diversity and differentiation among four populations of Tetreana mongolica on the Western Ordos plateau were studied using vertical slab polyacrylamide gel electrophonesis.Allozyme electrophonesis indicated relatively high level of genetic variation in this species with P=0.60,A=1.6,He=0.245.There existed low degree of population differentiation among the four populations with GST value being 0.051,significant different with other endangered species.The high intrapopulation variation and low interpopulation differentiation could explained that the different populations might originate from the same one and genetic drift or inbreeding depression had not influenced primary process of genetic diversity.%利用垂直板聚丙烯酰胺凝胶电泳技术,对西鄂尔多斯高原特有种四合木(Tetraena mogolica)4个种群遗传多样性和遗传分化进行了初步研究。电泳结果表明,四合木在种和种群水平维持较高的遗传多样性,多态位点百分率P=60%,等位基因平均数A=1.6,平均期望杂合度He=0.245。4个种群之间遗传分化很小,基因分化系数GST只有0.052,明显不同于其它濒危物种。四合木种群较高的遗传多样性和极低的种群间分化,说明不同的种群可能有共同的起源,随机遗传漂变和近交衰退不是影响遗传多样性的主要过程。

  19. Reservoir Stress and Fracture Distributions of Su-10 Block in Ordos Basin%鄂尔多斯盆地苏10区块地应力与储集层裂缝分布

    郭鹏; 李春林; 哈文雷


    在分析区域构造应力场特征的基础上,根据有限元法的基本理论,建立了苏10区块合理的地质、力学模型。通过地应力场的数值模拟,给出目的层的最大水平主应力、最小水平主应力、最大剪应力、平均应力和形变能等值线分布图。根据"三维等效张应力(σT)""、破裂值(I)"和"单位体积的应变能(u)"3个评价指标得出综合评价系数(R综),根据R综得出的构造裂缝发育区与高产气井及钻井岩心裂缝的吻合程度较高。%This paper analyzes the regional tectonic stress field characteristics in Ordos basin,develops the reasonable geological and mechanical model of its Su-10 block based on the finite element basic theory,and presents the maximum horizontal principal stress,minimum horizontal principal stress,maximum shear stress,mean stress and deformation energy contour distribution diagram of the target zone by numerical simulation of the earth stress field.The evaluation indices such as "3-D equivalent tensile stress(σT)","crack value(I)" and "strain energy per volume(u)" are applied to get composite assessment factor(Rc) for quantitative description of the fracture development.It is indicated that the zones with developed structural fractures are more accordant with the results of the high-yield gas wells and the drilled core fracture description.

  20. A Comparison of Talent Environment among the three cities,Hohhot,Baotou and Ordos by the Comprehensive Index Method%基于综合指数法的呼包鄂三市人才环境比较

    王雅荣; 易娜


    城市人才环境能反映城市人才建设水平,影响城市人才的吸引和保留人才。而城市人才环境涉及政治、经济、文化、科技、教育、地理环境等多个方面的庞大复杂系统。本文基于文献分析构建人才环境指标体系,包含经济环境、生活环境、文化环境及政策环境4个维度下17个指标,通过专家法和层次分析法确定指标权重,建立人才环境评价模型。结果显示:经济环境指数鄂尔多斯市第一,生活环境指数鄂尔多斯市第一,文化环境指数呼市第一,政策环境指数包头市第一,人才环境综合指数包头市第一,并进一步提出三个城市环境比较弱势方面的提升建议。%A city talent environment can reflect a city level of talent construction,which also influences city talent attraction and reten-tion. City talent environment is a complex system which involves politics,economy,culture,science and technology,education,geo-graphical environment and other aspects. Based on the literature analysis,this paper constructs an indicator-system for talent environ-ment evaluation,including 4 first-class indicators such as economic environment,living environment,cultural environment and political environment and 17 secondary indicators. Then adopting Delphi and AHP methods to confirm different weight on the two class indica-tors,the talent environment evaluation model is established. The paper appraises the status of talent environment among the three cities,Hohhot,Baotou and Ordos by the talent environment evaluation model. The result shows that Erdos ranks first in economic envi-ronment and living environment, Hohhot ranks first in cultural environment, and Baotou ranks first in policy environment and compre-hensive talent environment. Eventually, proposals are further put forward to improve weaker talent environment among the three cities.

  1. 鄂尔多斯主体功能区划分及其土地可持续利用模式分析%A Study on Major Function-Oriented Zoning and Sustainable Land Use Patterns of Ordos

    蒙吉军; 艾木入拉; 刘洋


    主体功能区划分和土地可持续利用模式设计,对解决我国经济快速发展过程中社会经济和生态环境之间出现的矛盾具有重要的意义。选取位于我国北方农牧交错带的鄂尔多斯市为研究区,以全市52个乡(镇、苏木)作为基本研究单元,采用研究区2008年数据,基于资源环境承载力、现有开发密度和区域发展潜力,从土地资源、水资源、矿产资源、生态安全度、土地利用强度、水资源开发强度、矿产资源开发强度、区位优势、科技潜力和经济活力等构建了主体功能区划分的指标体系,并运用变异系数法确定各指标权重,最终采用聚类分析与三维魔方图相结合的方法,将鄂尔多斯主体功能区划分为优化开发区、I级重点开发区、Ⅱ级重点开发区、限制开发区和禁止开发区,提出了五类主体功能区的协调发展机制和各功能区未来发展定位。分别选择各主体功能区内部的典型乡镇,优化开发区的达拉特旗树林召镇、I级重点开发区的伊金霍洛旗乌兰木伦镇、Ⅱ级重点开发区的乌审旗苏力德苏木和限制开发区的鄂托克旗阿尔巴斯苏木,基于1978年、1988年、2000年和2008年土地覆被数据,通过近30年来的土地利用变化和景观格局的分析,结合主体功能区的总体定位提出了土地可持续利用模式。结果对推进当地生态重建和促进土地可持续利用提供科学的支撑。%Major function-oriented zoning(MFOZ) and design of sustainable land use patterns are of great significance to ease the contradictions between the economy and the environment over the course of rapid development in China.The authors investigated Ordos City in a farming-grazing transitional zone of northern China,with 52 townships being selected as the fundamental planning units.Based on economic and statistical data of 2008 and considering resources and environmental capacity

  2. The distribution and evolution of fluid pressure and its influence on natural gas accumulation in the Upper Paleozoic of Shenmu-Yulin area, Ordos Basin


    On the basis of measuring the pressure distribution and analyzing its origin in the Carboniferous and Permian of Shenmu-Yulin area, the evolution history of ancient pressure is restored mainly by means of the basin numerical simulation technique, in which the paleo-pressure has been constrained by the compaction restoration and the examination of fluid inclusion temperature and pressure. Then the development and evolution history of abnormal pressure and its effect on gas migration and accumulation are investigated. Studies show that the pressure in southeastern and northwestern parts of studied area is near to hydrostatic pressure, whereas in the remainder vast area the pressure is lower than the hydrostatic pressure, which is caused by difficulty to measure pressure accurately in tight reservoir bed, the calculating error caused by in-coordinate between topography relief and surface of water potential, pressure lessening due to formation arising and erosion. There are geological factors beneficial to forming abnormal high pressure in the Upper Palaeozoic. On the distraction of measured pressure, paleo-pressure data from compaction restoration and fluid inclusion temperature and pressure exa- mining, the evolution history of ancient pressure is restored by the basin numerical simulation technique. It is pointed out that there are at least two high peaks of overpressure in which the highest value of excess pressure could be 5 to 25 MPa. Major gas accumulated in main producing bed of Shanxi Fm (P1s) and lower Shihezi Fm (P2x), because of two-fold control from capillary barrier and overpressure seal in upper Shihezi Fm (P2s). In the middle and southern districts, the two periods of Later Jurassic to the middle of Early Cretaceous, and middle of Later Cretaceous to Palaeocene are main periods of gas migration and accumulation, while they belong to readjustment period of gas reservoirs after middle of Neocene.

  3. 传统信仰文化在当代文化多元格局中的作用——以鄂尔多斯地区为例%The Function of Traditional Beliefs Culture on the Multi-pattern of Contemporary Culture——Example of the Ordos Region



    Cultural diversity is the traditions and characteristics of the cultural form of Inner Mongolia.National traditional culture is the important part and valuable resources of multi-culture in our region.Ordos is one of the regions there Mongolian traditional culture and especially traditional beliefs culture be retained more complete.Such as Oboo worship、Sulde worship from Shamanism、worship Etiquette culture that be the core of Genghis Khan and rich Buddhist cultural resources.These traditional beliefs culture are not only the distinctive characteristics of Ordos culture but also the important human resources that building a new culture system of multi-cultural coexistence and common prosperity.%文化多元性是内蒙古文化构成的一大传统和特色。民族传统文化是我区多元文化的重要组成部分和宝贵资源。鄂尔多斯地区是蒙古族传统文化,尤其是传统信仰文化保留较多、较完整的地区之一。如源于萨满教的敖包祭祀、苏力德祭祀以及以成吉思汗崇拜为核心的祭祀礼仪文化和丰富的佛教文化资源。这些传统的信仰文化资源不仅是鄂尔多斯文化的鲜明特征,而且也是构建多种文化并存共荣的新文化体系的重要人文资源。

  4. Galaxy formation

    Silk, Joseph; Dvorkin, Irina


    Galaxy formation is at the forefront of observation and theory in cosmology. An improved understanding is essential for improving our knowledge both of the cosmological parameters, of the contents of the universe, and of our origins. In these lectures intended for graduate students, galaxy formation theory is reviewed and confronted with recent observational issues. In Lecture 1, the following topics are presented: star formation considerations, including IMF, star formation efficiency and star formation rate, the origin of the galaxy luminosity function, and feedback in dwarf galaxies. In Lecture 2, we describe formation of disks and massive spheroids, including the growth of supermassive black holes, negative feedback in spheroids, the AGN-star formation connection, star formation rates at high redshift and the baryon fraction in galaxies.

  5. Fracture Identification in Honghe Oilfield,Ordos Basin%鄂尔多斯盆地红河油田裂缝识别

    许君玉; 许新


    Honghe oilfield is a typical low porosity and low permeability reservoir and the reservoir fractures are developed widely . According to the observation of core and imaging logging data ,there are mostly high‐angle and vertical fractures in the reservoir .They are mostly sinusoid display in imaging . There are two types of response characteristics of fractures in conventional logging curves :① dual induction ,8 laterolog and array induction data are all low ,8 laterolog resistivity log data and dual induction resistivity log data appear to be positive difference ,dual diameters extension is minor ,sonic log data and neutron log data are high ,and density log data are low . ② High dual induction resistivity log data appear to be positive difference ,8 laterolog log data and dual induction data are positive difference in the upper layers and are negative difference in the lower layers .Sonic and density log data are low ,neutron log data are high . Fractures are deviation from the trend line in the R/S curve of variable scale analysis map ,and became approximate line segment .It has been verified by core and imaging data that the method has achieved a high fracture identification rate . Also , the fractures development is predicated and its relationship with single well productivity is discussed . The results show that the single well productivity is improved in the fractures developed formations . Drilling core and image log data show this method has high fracture identification rate .%红河油田为典型的低孔隙度低渗透率油藏,储层裂缝广泛发育。通过岩心观察、成像测井识别等手段对其裂缝特征进行了描述。研究发现该研究区裂缝在岩心上多为高角度裂缝和垂直裂缝,在成像上多为正弦波曲线显示。裂缝在双感应、八侧向和阵列感应测井曲线上均显示低值,八侧向与双感应测井值正差异;双井径微扩径,声波、中子值增大,密度值减小;在

  6. Soil formation.

    Breemen, van N.; Buurman, P.


    Soil Formation deals with qualitative and quantitative aspects of soil formation (or pedogenesis) and the underlying chemical, biological, and physical processes. The starting point of the text is the process - and not soil classification. Effects of weathering and new formation of minerals, mobilis

  7. Geochemical Characteristics of REE in Jurassic Coal of Yan'an Formation from Dongsheng Coalfield

    赵峰华; 丛志远; 彭苏萍; 唐跃刚; 任德贻


    Concentrations of rare earth elements (REE) in Jurassic coal of YanAn Formation from Dongsheng coalfield located in the northeast of Ordos basin were determined by instrumental neutron activation analysis (INAA). Curves of distrib ution pattern of REE were drawn, and many geochemical parameters were calculated . The result shows that 1) The contents of REE in Jurassic coal with low ash an d sulfur are lower than those of Carboniferous and Permian coal from the Basin of North China; 2) Inside the Dongsheng coalfield, coal from the north has high er contents of REE than that form the south because the north is near the area of source rock which is the main supplier of REE, while the south is far away from the area of source rocks; 3) Although Jurassic coal in Dongsheng is the low-ash coal with less than 10%, the contents of REE are still proportional to ash yie ld of ash and SiO2 contents. 4) Although the Jurassic coal in Dongsheng were deposited in oxidative continental environment of river-lake, Eu depletion of RE E I n coal commonly exists, and positive abnormity of Ce dose not exist. This reflec ts the REE distribution pattern of REE in source rock of continental area; and 5) Compared with other rocks, coal shows extremely complexity of distribution pa ttern of REE, which is the result of continuous alteration and redistribution of matter in coal occurred in open basin system.

  8. Study on Oil/gas Boiling Inclusion Group of Chang-8 Oil-bearing Bed in Zhiluo Oilfield, the Southern of Ordos Basin%鄂尔多斯盆地南部直罗油田长8油层油气沸腾包裹体群研究

    王志辉; 黄伟


    运用激光拉曼光谱、包裹体充填度测定等方法对鄂尔多斯盆地直罗油田富南3井、6井长8油层裂缝岩芯充填物中包裹体群进行分析,发现富南3井、6井与英旺油田英16井长8油层中油气沸腾包裹体群完全相同,密集分布的气泡不停晃动,证实油气沸腾包裹体群不是孤立的、偶然的地质现象.富南3井、6井和英16井长8油层裂缝岩芯的原始裂缝性质为滑动-剪切裂缝和剪切裂缝,在区域构造的作用下,反复发生拉张-挤压交替活动;在拉张发生的瞬间,与裂缝沟通的油层里的原油发生减压沸腾,原油中的轻质馏分和其他流体进入裂缝空间;在随后的挤压发生时,裂缝基本封闭,一部分流体返回原来的油层,一部分被挤到别的裂隙空间形成新的油藏;残留在裂缝里的碳酸钙,在较高的地层压力下逐渐结晶,并把残留的轻质馏分包裹,形成油气包裹体;这些油气包裹体形成压力较高,又包裹着成分类似液化气的轻质馏分,在常温常压下就处于沸腾状态;这样的过程反复进行,在裂缝充填物中形成了沿着晶体生长线以及成片、成带分布的油气沸腾包裹体群.上述油气沸腾包裹体群的形成过程就是油气的地震泵运移机制,丰富了油气运移地震泵地质模型.%By the means of laser Raman spectroscopy and filling degree of inclusion) the inclusion groups of fillings of Chang-8 oil-bearing beds from wells Funan3 and Funan6 in Zhiluo Oilfield, the southern of Ordos Basin were studied. The results showed that the oil/gas boiling inclusion groups of Chang-8 oil-bearing beds from wells Funan3 and Funan6 were exactly the same to that from well Yingl6 in Yingwang Oilfield, and a lot of bubbles moved constantly; the geological phenomenon for oil/gas boiling inclusion groups were not isolated and occasional. The characteristics of incipient fracture core of Chang-8 oil-bearing beds from wells Funan3, Funan6

  9. 鄂尔多斯盆地南部延7+8油层组滨浅湖滩坝体系沉积特征%Sedimentary characteristics of the shore-shallow lacustrine beach bar system of Yan 7+8 oil reservoirs in southern Ordos Basin



    Retrograding sedimentary sequence and shore-shallow lacustrine beach bar system are developed in the Meso-zoic Jurassic Yan ’ an Formation in southern Ordos Basin ,and the latter has close paragenetic relationship with the mean-dering river delta around the lake basin of the Yan ’ an stage .Retrogradation and the destruction of the meandering delta provide clastic input for the development of the low-shallow lake beach bar system .During the depostion of Yan 7+8, An’ sai and Zhidan areas in the north of Shaaxi province were in shore-shallow lacustrine environment .Beach bar deposits were widely developed as the major part of sedimentation ,and can be divided into four microfacies types including beach sand,sand bar,sand sheet and mudstone .Generally,the beach bar sand bodies occur at the side of the river mouth and the flat open shore-shallow lake environment ,and are parallel with the lake shoreline .They are dominated by medium and fine sandstone,and have massive bedding ,wavy bedding,inclined wavy bedding and lenticular bedding ,etc.Beach sand is usually in sheet-like shape and is relatively thin.Bar sand,which is the most representative deposit of the beach bar system ,usually has banded shoreline-parallel distribution ,large thickness ,and lenticular shape on section ,reverse grading at the bottom and transgressive sequences in the middle and upper parts .A series of beach bar sandbodies superimposed with each other in different phases ,forming large-scale shoreline-parallel clustered reservoirs with high net-to-gross ratio . The mudstones of shore-shallow lake facies between the beach bars act as lateral barriers or overlying seals of the beach bar sandbodies .The sedimentary characteristics of the shore-shallow lacustrine beach bar system have significant influ-ences on reservoir development and oil/gas accumulation of the Yan ’ an Formation.%鄂南中生界侏罗系延安组发育退积型沉积层序及滨浅湖滩坝沉积体系;滨浅湖滩坝

  10. Comprehensive Log Evaluation for Coalbed Methane Reservoir in Eastern Block of Ordos Basin%鄂东气田煤层气储层测井综合评价方法研究

    刘之的; 杨秀春; 陈彩红; 张继坤


    It has an important significance for coalbed methane exploration and development that accurately and comprehensively evaluating the coalbed methane reservoir with log data.In view of many parameters affecting the performance of coalbed methane reservoir,as well as geological features,physical properties and characteristics of the coal reservoir,six indexes are selected to reflect the CBM reservoir quality.They are coal petrography index,fracture growth index,fracture porosity index,permeability index,coalbed methane content index and effective thickness index.Due to the strong heterogeneity of coalbed methane reservoirs of gas field in eastern block of Ordos basin,the reservoir parameters are often random and fuzzy in the comprehensive evaluation of the coalbed methane reservoir,therefore we suggest a fuzzy comprehensive evaluation model.Using log data which have abundant geological information of coalbed methane reservoir and the laboratory analysis data of actual coal core,the fuzzy evaluation set is established to evaluate the coalbed methane reservoir,based on which the fuzzy comprehensive evaluation model is carried out for the work area.The comprehensive log evaluation result has a good consistency with laboratory test and analysis result.%影响煤层气储层性能的参数众多.从煤储层地质特征、物性特征和储集特征出发,优选出能够充分反映煤层气储层优质与否并且利用测井资料易于求取的6个指标:煤岩性质和结构、裂缝发育程度、裂缝孔隙度、渗透率、煤层气含量和有效厚度.针对鄂东气田煤层气储层非均质性强,煤层气储层综合评价中存在储层参数的随机性、模糊性等诸多问题,给出煤层气储层模糊综合评价模型.利用测井资料和实际煤岩心室内分析资料,构建用于煤层气储层测井综合评价的模糊评判集,并基于此模糊评判集,采用模糊综合评价模型对工区内重点井进行了模糊综合评判.该评

  11. Unconformity structure types and hydrocarbon migration characteristics in Hangjinqi area of Ordos Basin%鄂尔多斯盆地杭锦旗地区不整合结构类型及运移特征

    孙晓; 李良; 丁超


    Hangjinqi Block is located in northern Ordos Basin and has three unconformities including the Upper Paleozo -ic-Lower Paleozoic,Upper Paleozoic-Paleozoic and Upper Paleozoic-Archean.Logging data,core data and cutting logging data were integrated to study the characteristics of unconformity space structure in detail .In addition,hydrocarbon migra-tion characteristics of various types of unconformity structure were also analyzed in combination with the carriers above and below the conformities and distribution of gas reservoir .It also figured out the distribution area of advantageous migra-tion pathways .The research shows that there are nine unconformity configuration types in Hangjinqi Block ,namely sand-mud-sand,sand-mud-limestone, sand-mud-metamorphic rock, sand-metamorphic rock, sand-limestone, mud-mud-sand, mud-mud-limestone,mud-mud-metamorphic rock and sand-mud-mud.And there are three kinds of migration pathways , namely double migration pathway I-type,single migration pathway Ⅱ1-type and single migration pathway Ⅱ2-type,among which the double migration pathway Ⅰ-type is the primary pathway and is mainly distributed in three areas .The largest ar-ea is in the central-eastern part of the block ,and its target traps are Shilijiahan in the south of fault and ShiguhaoYin the north of fault .And the second area lies in the western block and its target trap is Xinzhao .The smallest area lies in the eastern block and its target trap is Azhen .Double migration pathway is poorly developed in Shilijiahan trap and is favora-ble for the in-situ enrichement and accumulation of gas .%杭锦旗地区地处鄂尔多斯盆地北部边缘,存在上古生界-下古生界、上古生界-元古生界、上古生界-太古界3个不整合面.根据已钻井测井响应特征以及岩心观察和岩屑录井资料,对研究区不整合空间结构特征进行了详细研究,同时结合不整合面上下岩性结构的输导作用以及气藏分布等因素,分析了不整

  12. Geochemical Characteristics and Genesis of Shale Gas in the South of Ordos Basin%鄂尔多斯盆地南部页岩气地化特征及成因

    高栋臣; 姜呈馥; 孙兵华; 许小强; 仝敏波


    对鄂尔多斯盆地南部页岩气井进行井口生产气取样、岩心解析气取样,进行天然气组分分析和碳氢同位素测试。明确了延长组长7段、长9段天然气组分特征,碳氢同位素特征,结合天然气分析相关图版探讨了天然气的成因类型及来源。结果表明,研究区天然气为有机成因气,干燥系数小,含有一定量的重烃成分,属于典型的湿气,排除了生物气及高温裂解气的可能。乙烷碳同位素特征及天然气类型图版分析表明该区页岩气为典型的油型气。长7段页岩气碳同位素组成序列整体为δ13 C1﹤δ13 C2﹤δ13 C3﹤δ13 C4,为正常序列,少量样品显示同位素反转,长9段长7段页岩气碳同位素组成序列为δ13 C1﹤δ13 C2﹤δ13 C3﹤δ13 C4。认为长7段页岩气来自本层段张家滩页岩,但局部地区存在运移通道,发生了天然气混合,长9段页岩气来自于长9段李家畔页岩。%Shale gas samples from production and core desorption were collected in the south of Ordos basin. Com-position and isotopes of carbon and hydrogen were tested and analyzed. Combining with diagram of natural gas type,we discussed the shale gas type and its origin in the chang7 and chang9 member. The result showed as fol-lows:the natural gas of the two members was organic origin. With small dry coefficient and a certain amount of heavy hydrocarbon,the gases were typical wet gas,not biogenic and thermal -cracking. 13C of ethane showed that the natural gases were typical organic genetic oil type gas. In general,the isotope of chang7 shale gas carbon was characterized by δ13 C1 ﹤δ13 C2 ﹤δ13 C3 ﹤δ13 C4 ,while small amount of samples showed reversal sequence. The iso-tope of chang9 shale gas carbon was characterized by δ13 C1 ﹤δ13 C2 ﹤δ13 C3 ﹤δ13 C4 . We could draw the conclusion that the origin of chang7 shale gas was Zhangjiatan shale,in some part of which migration pathway developed

  13. Paleotopographic controls on facies development in various types of braid-delta depositional systems in lacustrine basins in China

    Dong Feng


    Full Text Available Braid-delta depositional systems are widely developed in most continental basins in China. Research indicates that, for different types of braid delta, the facies sequence and association, which are critical to the prediction of the distribution of reservoirs, differ greatly. This study illustrates the differences in braid-delta depositional systems in terms of sedimentary characteristics, associated systems and reservoir distributions using three typical paleodeltas in western China: the Zhenbei delta of the upper Triassic Yanchang Formation in the Ordos Basin, the Yuanba delta of the upper Triassic Xujiahe Formation in the Sichuan Basin and the Jimsar delta of the upper Permian Wutonggou Formation in the Junggar Basin. A stratigraphic framework was established using seismic data, logs and cores by choosing stable mud sections as regional correlation markers and, topographies of these deltas were reconstructed based on the decompaction and paleobathymetric corrections. Based on both the paleotopography of these deltas and the differences of their sedimentary facies, these braided deltas can be classified into two systems: steep-gradient braid-delta-turbidite system and low-gradient braid-delta-lacustrine system. Moreover, the low-gradient braid-delta-lacustrine system can be further divided into interfingered and sharp contact sub-types according to the contact relation between the delta sands and lacustrine muds. This study shows that the paleotopography of basin margins strongly controls the accommodation as braid deltas prograde into lacustrine basins and, influences the location of the shoreline in response to changes in the lake level. Furthermore, paleotopography plays a significant role in facies and reservoir distribution which is important for petroleum exploration and development.

  14. Kongresa Rezolucio: Al nova monda lingva ordo


    La 81-a Universala Kongreso de Esperanto, OkaZinta de la 20-a gis la 27-a de julio 1996 enPrago, eeha RespubIiko, kie kunvenis 2972kongresanoj el 66 landoj,audinte la debatojn kaj rekomendojn de eksper-toj el Unuigintaj Nacioj, Unesko, Europa Par-lamento kaj aliaj internaciaj organizajoj,kadrede la Nitobe-Simpozio de InternaciajOrganizajoj pri"Lingvo por internaciaj paco kajdemokratio". konstatinte la gravecon de la principoj esprimi-’taj en la Manifesto de Prago,

  15. 中国北方农牧交错带土地集约利用评价研究——以内蒙古鄂尔多斯市为例%Evaluation of land use intensity in agro-pastoral zone of North China:a case of Ordos City of Inner Mongolia

    燕群; 蒙吉军; 康玉芳


    北方农牧交错带作为我国传统农业区与畜牧业区交汇和过渡的地带,其土地集约利用有突出的特点.以内蒙古鄂尔多斯市为例,从北方农牧交错带土地集约利用的内涵出发,构建评价指标体系,分别运用熵值法和人工神经网络模型计算集约度.结果显示,2003-2007年鄂尔多斯土地集约度数值总体上升;利用效率对鄂尔多斯土地集约利用影响最大,其次是利用程度和投入强度,持续状况的影响最小.结果表明,熵值法和人工神经网络模型均适用于土地复杂系统的集约利用评价计算.相对于其它方法,熵值法在一定程度上避免了赋权的片面性和主观性,人工神经网络模型弥补了传统的多指标综合评价方法主观性强、缺乏自学能力的缺陷.%As the transition zone of traditional agricultural area and animal husbandry of China, agro-pastoral transitional zone is prominent in land use intensity. Taking Ordos City in Inner Mongolia as an example, this paper made a calculation of land use intensity of Ordos. On the basis of intensive land use, an index system was built to represent the status of land use intensity, which included 18 indexes in index layer like urban construction land per capita, population density of built up area, proportion of real estate development and so on. Neuron structure of BP network and entropy method was used to calculate the intensity value, and both of them got a similar conclusion. The result showed that, the intensity represented a rising trend during 2003 - 2007, which showed the positive impact of the strategy of industrialization, urbanization, industrialization of agriculture and animal husbandry especially after the eleventh five-year plan. Secondly, for the indexes of target layer, utilization efficiency had the most significant influence on land use intensity in Ordos. Utilization degree took the second place with input intensity following , and sustainable development

  16. Formation and evolution of the Chinese marine basins


    There are plenty of petroleum resources in the Chinese marine basins, which will be the potential exploration regions of petroleum in the 21 st century. The formation and evolution of the Chinese marine basins have mainly undergone two major tectonic epochs and five tectonic evolution stages. The first major tectonic epoch is the early Paleozoic plate divergence and drifting epoch during which the marine basins were formed, and the second one is the late Paleozoic plate convergence and collision epoch during which the pre-existent marine basins were superimposed and modified. The five tectonic northward collage and convergence of continental plates and the development of the paralic sedimencollage and the superimposition of lacustrine basins controlled by the inland subsidence during Late erosion or breakage of marine basins influenced by the plate tectonic activities of Neo-Tethys Ocean sion and basin-range coupling in the margin of the marine basins caused by the collision between India and Eurasia Plates and its long-distance effect since Neocene. The process of the tectonic evolution has controlled the petroleum geologic characteristics of Chinese marine basins, and a material foundation for the formation of oil and gas reservoirs has been built up via the formation of Paleozoic marine basins, and the Mesozoic-Cenozoic tectonic superimposition and modification have controlled the key conditions of hydrocarbon accumulation and preservation. From the Late Proterozoic to the Early Paleozoic, the stratigraphic sequences of the deep-water shale and continental margin marine carbonate rocks in the ancient plate floating in the oceans have developed high-quality marine source rocks and reef-shoal reservoirs. In Late Paleozoic, the crustal plates converged and uplifted into continent and the paleouplifts in the intra-cratonic basins have become good reservoirs of hydrocarbon migration and accumulation, and paralic coal beds have formed regional cap rocks. The Mesozoic

  17. Galaxy Formation

    Sparre, Martin

    Galaxy formation is an enormously complex discipline due to the many physical processes that play a role in shaping galaxies. The objective of this thesis is to study galaxy formation with two different approaches: First, numerical simulations are used to study the structure of dark matter and how...... galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof......-the-art cosmological simulation, Illustris, follow a tight relation between star formation rate and stellar mass. This relation agrees well with the observed relation at a redshift of z = 0 and z = 4, but at intermediate redshifts of z ' 2 the normalisation is lower than in real observations. This is highlighted...

  18. Ecological security assessment on tourism resources development in ecological fragile district A case of Ordos, Inner Mongolia%生态脆弱地区旅游资源开发的生态安全评价——以内蒙古鄂尔多斯市为例

    贾铁飞; 冯亚芬


    以地处我国农牧交错、生态脆弱的内蒙古鄂尔多斯市为例,借鉴国内外生态安全评价方法,通过对10个重点旅游资源区进行详细调查,构建了区域性旅游开发生态安全评价的指标体系,并对旅游资源赋存环境生态承受能力、旅游资源开发生态影响力的各项指标因子进行权重分析和量化赋分,对研究区旅游资源开发的生态安全状况进行了综合评价。研究表明:除鄂尔多斯西部荒漠、沙漠生态地区旅游资源开发的生态安全性较差外,其余重点旅游资源区均处于较安全状态,但生态安全隐患仍然存在;同时,10个重点资源区中,初步开发区(开发5年以内)和深度开发区(开发10年以上)的生态安全状况较好,而中度开发区(开发5-10年)的生态安全性较差,说明中度开发阶段是出现生态危机机率较大的时期。%Inner Mongolia is located in China~ Farming- grazing transitional belt, an ecological fragile district. This article took Ordos as an example and built the ecological security assessment index system from referring the ecological security assessment methods and investigating the 10 major tourism resources detailed. In this paper, each factor~ weight of the ecological capacity of tourism resources environment and the ecological environment in- fluence of tourism resources development was analyzed and quantified. According to above analysis, the ecologi- cal security situation of tourism resources development in Ordos City was evaluated comprehensively. The results are: most tourism resources in the area are relatively safe in addition to the tourism resources in the desert envi- ronment of western Ordos, but there still hide dangers in ecological security. At the same time, among the 10 major tourism resources, the ecological security situation of the initial development resources ( the development within 5 years) and depth development resources (the development

  19. 鄂尔多斯盆地东胜砂岩型铀矿床成矿水化学过程探讨%The Water-rock Interaction Process of the Dongsheng Sandstone-type Uranium Deposit, Ordos Basin

    吴兆剑; 易超; 韩效忠; 祁才吉; 惠小朝


    In order to investigate the relationship of the hydrochemical process to the uranium metallogenic mechanism of the Dongsheng uranium deposit in Ordos basin, the authors conducted contrastive mineralogical and REE geochemical analysis of non-mineralized samples in the oxidation zone and mineralized samples in the redox transitional zone by means of general slice, electron microprobe, clay mineral X-diffraction, SEM and chemical testing. Mineralogical studies show that argillic alteration and sericitization of plagioclase can be observed in all samples, and coffinite is the main uranium mineral and is always adsorbed by fragments or carbon dust. Another interesting phenomenon is that the mineralized samples in the redox transitional zone contain more carbon dust and carbonate than those in the oxidation zone. Geochemical studies indicate that non-mineralized samples in the oxidation zone and low mineralization samples in the redox transitional zone show flat REE patterns in PAAS-normalized rare earth element plots. However, samples with high uranium content in the redox transitional zone show two different REE patterns: samples with carbon dust show a MREE enrichment pattern and those with carbonate show a HREE enrichment pattern. Mineralogical and geochemical differences of samples from different zones indicate that aqueous chemical reaction is the main uranium mineralization rather than carbon absorption. In the aqueous chemical process, CO32-which prefers combining UO22+and HRE3+is the main inorganic complex anion in the mineralized hydrothermal water, and argillic alteration and sericitization of plagioclase with Ca2+and SiO44-play an important role in the metallogenic process.%为了研究鄂尔多斯盆地东胜砂岩型铀矿成矿水化学过程,利用光薄片、电子探针、X 射线衍射、扫描电镜和化学分析等方法对比分析了氧化带无矿化样品、氧化还原过渡带中低矿化及高铀样品的矿物学和地球化学特征。

  20. The Challenges and Sustainable Development of New Rural Cooperative Medical System in Ordos%浅谈鄂尔多斯市新型农村牧区合作医疗制度面临的挑战与可持续性发展

    杨恒辉; 李大旭; 石敏


    China’s New Rural Cooperative Medical System(NCMS) was launched in 2003. After a decade of experimental and continuous improvement, NCMS has run smoothly and comprehensively covered rural area. With gradually increasing of the funding criteria of NCMS, the benefit level of the farmers and herders has been improved constantly. NCMS solved the problem of basic healthcare insurance of developing countries with the largest rural population in the world. NCMS was considered as the most suitable system for the conditions of China and the greatest progress of Chinese medical reform. Taking Ordos of Inner Mongolia as an example, this paper discussed the development history, system design, current problems and the sustainable developmental path of NCMS in Ordos, which lay a theoretical foundation for further suggestion.%我国新型农村合作医疗自2003年启动,经过十年的试点探索和完善推广,目前已经全面覆盖,平稳运行,新农合的筹资水平逐年提高,广大农牧民群众受益程度也在不断提高。中国用最符合国情的制度,解决了世界上农民人口最多的发展中国家的基本医疗保障问题,是医改实施五年来的最大成就和亮点。本文以内蒙古鄂尔多斯市为例,探讨了鄂尔多斯市新农合作的发展历程,制度设计,目前存在的主要问题以及可持续发展的总体思路,为进一步提供政策建议奠定理论基础。

  1. Galaxy Formation

    Sparre, Martin

    galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof......-the-art cosmological simulation, Illustris, follow a tight relation between star formation rate and stellar mass. This relation agrees well with the observed relation at a redshift of z = 0 and z = 4, but at intermediate redshifts of z ' 2 the normalisation is lower than in real observations. This is highlighted...... of GRB host galaxies is affected by the fact that GRBs appear mainly to happen in low-metallicity galaxies. Solving this problem will make it possible to derive the total cosmic star formation rate more reliably from number counts of GRBs....

  2. Hippocampal formation

    Cappaert, N.L.M.; van Strien, N.M.; Witter, M.P.; Paxinos, G.


    The hippocampal formation and parahippocampal region are prominent components of the rat nervous system and play a crucial role in learning, memory, and spatial navigation. Many new details regarding the entorhinal cortex have been discovered since the previous edition, and the growing interest in t

  3. Galaxy formation.

    Peebles, P J


    It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z approximately 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation.

  4. Cloud Formation

    Graham, Mark Talmage


    Cloud formation is crucial to the heritage of modern physics, and there is a rich literature on this important topic. In 1927, Charles T.R. Wilson was awarded the Nobel Prize in physics for applications of the cloud chamber.2 Wilson was inspired to study cloud formation after working at a meteorological observatory on top of the highest mountain in Scotland, Ben Nevis, and testified near the end of his life, "The whole of my scientific work undoubtedly developed from the experiments I was led to make by what I saw during my fortnight on Ben Nevis in September 1894."3 To form clouds, Wilson used the sudden expansion of humid air.4 Any structure the cloud may have is spoiled by turbulence in the sudden expansion, but in 1912 Wilson got ion tracks to show up by using strobe photography of the chamber immediately upon expansion.5 In the interim, Millikan's study in 1909 of the formation of cloud droplets around individual ions was the first in which the electron charge was isolated. This study led to his famous oil drop experiment.6 To Millikan, as to Wilson, meteorology and physics were professionally indistinct. With his meteorological physics expertise, in WWI Millikan commanded perhaps the first meteorological observation and forecasting team essential to military operation in history.7 But even during peacetime meteorology is so much of a concern to everyone that a regular news segment is dedicated to it. Weather is the universal conversation topic, and life on land could not exist as we know it without clouds. One wonders then, why cloud formation is never covered in physics texts.

  5. Cement Formation

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten


    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including...... an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  6. Galaxy Formation

    Longair, Malcolm S


    This second edition of Galaxy Formation is an up-to-date text on astrophysical cosmology, expounding the structure of the classical cosmological models from a contemporary viewpoint. This forms the background to a detailed study of the origin of structure and galaxies in the Universe. The derivations of many of the most important results are derived by simple physical arguments which illuminate the results of more advanced treatments. A very wide range of observational data is brought to bear upon these problems, including the most recent results from WMAP, the Hubble Space Telescope, galaxy surveys like the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey, studies of Type 1a supernovae, and many other observations.

  7. Post-Neogene Structural Evolution:An Important Geological Stage in the Formation of Gas Reservoirs in China

    WANG Tingbin


    Tectonic movements since the Neogene have been the major developmental and evolutional stages of the latest global crustal deformation and orogenic movements. China is located in a triangular area bounded by the Indian landmass, the West Siberian landmass and the Pacific Plate, characterized by relatively active tectonic movements since the Neogene, and in this region, natural gas would have been very easy to dissipate, or difficult to preserve. Therefore, the characteristics of post-Neogene tectonic movements offer important geological factors in researching the formation and preservation of gas reservoirs in China. Summarizing the reservoiring history of gas fields in China, although there are some differences between various basins, they are all affected by the tectonic movements since the Neogene. These movements have certainly caused destruction to the reservoiring and distribution of natural gas in China, which has resulted in a certain dissipation of natural gas in some basins. As a whole, however, they have mainly promoted the reservoiring and accumulation of natural gas: (1) a series of China-type foreland basins have been formed between basins and ridges in western China, which provide favorable conditions for the formation of large and medium gas fields, as well as controlling the finalization of gas reservoirs in the basins; (2) rows and belts of anticlines have been formed in the Sichuan Basin in central China, which have been the major stages of the formation and finalization of gas reservoirs in that basin; the integral and quick rising and lifting, and a further west-dipping in the Ordos Basin have resulted in a further accumulation of natural gas in gas fields from Jingbian to Uxin; (3) in eastem China, the Bohai movement in the late Pliocene has provided favorable geological conditions for lately-formed gas reservoirs in the Bohai Sea area mainly composed of the Bozhong depression; and it also resulted in secondary hydrocarbon generation and

  8. Provenances Analysis and Depositional Systems of upper Triassic Chang 63 Sand Set in Huanxian Region in Ordos Basin%鄂尔多斯盆地环县地区上三叠统长63物源分析及沉积体系

    邵远; 文佳涛; 程文; 邱安南; 郭莉


    Through identifying and analysing the 120 pieces of rock slices, arranging and analysing the 60 measured heavy mineral data, calculationing and reaseaching the 40 grain size data, as the same time considering area sedimentary facies setup, and combining predecessors correlation data, provenance analysis of upper Triassic Chang 63 sand set in Huanxian region in Ordos Basin is maken. The result indicates that provenance of Huanxian region mainly lay to westen of the study area, secondly northeastern, a little northern. Builting up depositional systems of Chang 63 sand set in combination with regional geological characteristic analysis is presented.%通过120块岩石薄片的鉴定分析,对60个实测重矿物资料的整理和分析,对40个粒度分析资料的统计和研究,同时考虑区域沉积相格局,并结合前人有关资料,对鄂尔多斯盆地环县地区上三叠统延长组长63沉积期进行了物源分析.结果表明,环县地区的物源主要来源于研究区的西方,其次来源于研究区的东北方,少量来源于北方.结合区域地质特征分析,建立了研究区长63的沉积体系.

  9. Pattern Formation

    Hoyle, Rebecca


    From the stripes of a zebra and the spots on a leopard's back to the ripples on a sandy beach or desert dune, regular patterns arise everywhere in nature. The appearance and evolution of these phenomena has been a focus of recent research activity across several disciplines. This book provides an introduction to the range of mathematical theory and methods used to analyse and explain these often intricate and beautiful patterns. Bringing together several different approaches, from group theoretic methods to envelope equations and theory of patterns in large-aspect ratio-systems, the book also provides insight behind the selection of one pattern over another. Suitable as an upper-undergraduate textbook for mathematics students or as a fascinating, engaging, and fully illustrated resource for readers in physics and biology, Rebecca Hoyle's book, using a non-partisan approach, unifies a range of techniques used by active researchers in this growing field. Accessible description of the mathematical theory behind fascinating pattern formation in areas such as biology, physics and materials science Collects recent research for the first time in an upper level textbook Features a number of exercises - with solutions online - and worked examples

  10. Analysis on the thermal history and uplift process of Zijinshan intrusive complex in the eastern Ordos basin%鄂尔多斯盆地东缘紫金山侵入岩热演化史与隆升过程分析

    陈刚; 丁超; 徐黎明; 章辉若; 胡延旭; 杨甫; 李楠; 毛小妮


    运用LA-ICP MS锆石U-Pb定年、角闪石和黑云母40Ar-39Ar定年、锆石和磷灰石裂变径迹(FT)分析等构造热年代学研究方法,探讨分析了鄂尔多斯盆地东缘紫金山侵入岩的热演化历史及其抬升冷却过程.紫金山侵入岩主要由次透辉二长岩和正长岩组成,锆石U-Pb测年给出的岩浆侵位-结晶年龄为136.7 Ma,角闪石和黑云母40Ar-39Ar测年获得的岩浆结晶-固结年龄集中在133.1~130.4 Ma,表明紫金山侵入岩主要形成于早白垩世的136.7~130.4 Ma.侵入岩T-t轨迹与磷灰石FT模拟热史路径综合揭示了鄂尔多斯盆地东缘紫金山侵入岩抬升冷却的三个构造热演化阶段:1)136~120 Ma侵位岩浆结晶-固结阶段,岩体平均冷却速率高达52℃/Ma;2)120~30 Ma岩体相对缓慢抬升冷却阶段,平均抬升冷却速率为2.5℃/Ma;3) 30 Ma以来岩体快速抬升冷却阶段,平均抬升冷却速率3.6℃/Ma,尤以近10 Ma以来的快速抬升冷却最为显著,抬升冷却速率接近7℃/Ma.结合区域构造动力学环境分析认为,鄂尔多斯盆地东缘的紫金山岩浆活动与华北克拉通早白垩世构造体制转换过程的大规模岩浆活动属于相同时期、统一构造作用的产物,早白垩世末期以来由慢到快的差异抬升过程主要受控于华北克拉通东部(古)太平洋体系与其西南部特提斯体系之间相互联合、彼此消长的构造作用.%Thermochronological data of in-situ zircon U-Pb, hornblende and biotite 40Ar-39Ar, and zircon and apatite fission track (FT) are presented in this paper for studying the thermal history and uplift-cooling process of Zijinshan intrusive complex at the eastern margin of the Ordos basin in the central North China Craton (NCC). Alkaline intrusive rocks dominate the complex with the diopside monzonite and syenite as the dating samples in this work. Zircon U-Pb dating of the monzonite provides the initial crystallization age of the Early magmatic intrusion

  11. Analysis of magnetic anomaly and crystalline basement of the Yinshan orogen and the northern Ordos basin regions%阴山造山带和鄂尔多斯盆地北部磁异常场与结晶基底特征研究

    阮小敏; 滕吉文; 安玉林; 闫雅芬; 王谦身


    阴山造山带与鄂尔多斯盆地跨越不同的构造单元,是典型的盆、山耦合地带,且是构造活动强、弱的变异地域,了解该区结晶基底分布特征对于深化认识盆山耦合的深部要素和深层动力学过程具有十分重要的意义.本文在最新的高精度的地磁观测剖面和数据采集基础上,与航磁异常场在该区域上的展布进行集成研究.通过磁场特征分析以研究盆地和造山带地域的构造分区和结晶基底起伏,进而对该区的油、气能源和金属矿产资源分布特征及前景进行探讨.这一研究成果为进一步深化认识该区的深部构造格局及其深层动力学过程提供了深部介质磁性结构与属性的重要判据.%Yinshan orogen and the northern Ordos basin cross different tectonic units, they are typical of basin-mountain coupling zones and transition regions between strong and weak tectonic activities. As a result, the knowledge of the distribution of crystalline basement is of vital importance to identifying and understanding of deep factors contributing to basin-mountain coupling zone as well as deep dynamical processes. Based on updated and highly accurate observational data of geomagnetic profile, we also collect aero-magnetic data of this region, and study the crystalline basement of basin and orogenic belts and the characteristics of tectonicdivisions. Then we discuss the distribution features and good prospects of energy and resources in this region. The research results will inevitably provide solid evidence of magnetic structure and properties for further research on this region, including the internal structure and the deep dynamical processes.

  12. 鄂尔多斯盆地中西部奥陶纪热液活动的证据及其对储层发育的影响%Petrological Evidence of Ordovician Hydrothermal Activities and Its Geological Significance to Reservoir Development in Central and Western Parts of Ordos Basin

    王玉萍; 董春梅; 陈洪德; 苏中堂; 张长俊; 郝哲敏


    对岩石薄片镜下鉴定和阴极发光等分析表明,鄂尔多斯盆地中西部奥陶纪的热液活动在岩石学上的特征有:出现热液成因凝灰岩、马鞍状白云石、斑块状黄铁矿、自生石英、石英-萤石和天青石-方解石的热液矿物组合,白云石在阴极发光下呈昏暗色。发现热液流体活跃区域与西缘断裂带走向一致,受热液影响的储层孔隙度较其他储层孔隙度平均值高出2%~3%左右。认为研究区热液活动对奥陶系储层起着建设性作用,受热液影响的储层可作为油气勘探的有利目标之一。%The analysis of thin sections and cathode luminescence for core samples has shown several petrological characteristics of Ordovician hydrothermal activities in the central and western parts of Ordos Basin. The hydrothermal products commonly are hydrothermally-origined tuff, saddle dolomite, mottled pyrite and authigenic quartz and some hydrothermal mineral assemblages including quartz-fluorite and lapis lazuli-calcite, in which the hydrothermally-origined dolomite shows dark color in cathode luminescence. It is discovered that the strike of the hydrothermally active field follows the trend of faults in the western margin of the basin and the average porosity of hydrothermally-influenced reservoirs is 2%~3% higher than that of general reservoirs. It is concluded that hydrothermal activities play a constructive role in the Ordovician hydrothermal reservoirs, which are expected to be one of the most favorable exploration targets.


    哈斯苏荣; 永荣; 金海; 乌翠兰; 海鹰; 布音布和


    In order to realize the digitization and automation of fecal egg counting methods, the primary images of Nematodirus eggs,Chabertia eggs , Haemonchus contortus eggs, Trichostrongylus eggs, Oesophagostomum eggs, Bunostomum eggs, and Ostertagia eggs,came from generally higher infection rate of parasites in investigated area, were collected extensively based on the epidemiolagical investigation of main helminthiasis of naturally grazing Ordos merino sheep. All of primary images were segmented manually and background clean - up by photoshop9.0 software, and 7 kinds of nematode eggs'original image database was established initially. The database contains total of 1320 original egg images, and each of them contains more 100 images, which covering almost all forms of primary eggs. This work laid a good foundation for digital description and automatic identification of helminth eggs in feces.%为实现粪便虫卵检查法的数字化和自动化,本文在调查鄂尔多斯细毛羊消化道主要线虫病流行病学基础上,广泛收集感染率普遍较高的细颈线虫(Nematodirus)、夏伯特线虫(Chabertia)、捻转血矛线虫(Haemonchus contortus)、毛圆线虫(Trichostrongylus)、仰口线虫(Oesophagostomum)、食道口线虫(Bunostomum)和奥斯特线虫(Ostertagia)卵原始图像,并经photoshop9.0应用软件进行人工分割和背景清理,初步建立了以上7种线虫卵的原始图像库.虫卵图像库共包含1 320幅原始图像,每种虫卵图像至少100幅以上,基本涵盖了每种虫卵图像的多种表现形式,为后期的虫卵图像数字化描述和自动识别奠定了基础.

  14. Radiation Conversion Equations of the Landsat Series of Sensors-A Study Case of MSS, TM and ETM+ Images over the ORDOS Region%美国陆地卫星三代光学传感器的辐射转换方程--以鄂尔多斯地区MSS/TM/ETM+影像为例

    张舞燕; 马超; 刘清臣


    The radiation normalized equations was established by using the method of PIF with the three different images of Landsat MSS/TM/ETM+ of the ORDOS region. The radiation normalization processing to the three sen-sors′reflectance data of the red and near infrared band was taken, and the root-mean-square error, NDVI difference and the dynamic range were employed in analyzing and verifying the normalized images. The research showed that the corresponding band of three kinds of sensors had a very strong linear correlation ( R2> 0.92) , and the high ac-curate conversion with the RMSE less than 0.041 for corresponding bands of three sensors was accomplished by u-sing the obtained transformation equations. The calibration results effectively reduced the radiometric difference caused by the non-feature changes. The method of the paper completed the normalization of the surface reflectance for multi-temporal and multi-sensor data, and improved the conditions of the dynamic monitoring.%以鄂尔多斯地区的Landsat MSS/TM/ETM+3种不同影像数据为对象,利用伪不变特征( PIF)法建立辐射归一化方程,对3种传感器红光波段和近红外波段的反射率数据进行辐射归一化处理,并对辐射同化结果从均方根误差、NDVI差值以及动态范围3个方面进行了分析和验证。研究表明,3种传感器对应的波段具有极强的线性相关性(R2>0.92),利用研究得到的转换关系方程实现3种传感器对应波段的高精度转换( RMSE <0.041),校正结果有效地减小了非地物变化引起的辐射差异,实现了多时相、多传感器数据的反射率同化,改善了动态监测效果。

  15. Seismic data processing for Ordos basin with wave fields separation and denoising via SVD%SVD地震波场分离与去噪技术在鄂尔多斯盆地地震资料处理中的应用



    针对鄂尔多斯盆地地区地震资料自身的特点,本文依据地震信号传播的特性和波场之间的差异,通过多域(多种线性变换域和频域)奇异值分解(SVD),然后提取目标信号的奇异值重构地震信号的方法,实现地震波场分离与去噪处理.与传统SVD地震波场分离与去噪技术相比较,该方法的目的性更强,直接针对感兴趣的地震信号成分进行SVD波场分离与去噪,在提高地震资料信噪比的同时,确保了信号的高保真度和分辨率;同时,避免了以往SVD技术应用空间狭窄,有效信号损失严重等缺陷性.从实际资料处理结果来看,取得了较好的效果.%Under the characteristics of the Ordos Basin seismic data, in this paper, according to the propagation characteristics of seismic signal and the differences between wave fields, through the method with multi-domain (multi linear transformation domain and frequency domain) Singular Value Decomposition (SVD), and then extracting the singular value of the target signal to reconstruct the seismic signals, achieves seismic wave fields separation and denoising processing. Compare with the traditional technique of seismic wave field separation denoising via SVD, the purpose of the method is more direct in the interest seismic signal with wave field separation and denoising via SVD, which improve signal to noise ratio of seismic data, while ensure fidelity and resolution of signal. At the same time, avoid the defects that the using space is narrow and effective signal loss is serious with traditional SVD technology. From the results of actual data processing, this paper achieved good results.

  16. Diagenesis and The Porosity Evolution Analysis of Chang 2 Reservoir in Resiwan Oilfield,Ordos Basin%鄂尔多斯盆地子长油田热寺湾油区长2储层成岩作用及孔隙度演化定量分析

    宋珈萱; 弓虎军; 王永东; 杨燕; 马晓玲


    通过扫描电镜、铸体薄片以及X射线衍射等分析化验资料,对子长油田热寺湾油区长2储层的成岩作用及孔隙度演化进行分析研究,揭示了储层物性及孔隙演化的主要控制因素。研究表明:热寺湾油区长2储集层属于低孔特低渗油气储集层,主要发育原生粒间孔隙及次生溶蚀孔隙。孔隙度演化定量计算结果表明,原始孔隙度平均值为35.29%,成岩作用过程中,受压实作用损失的孔隙度平均为22.01%,受胶结作用损失的孔隙度平均为4.13%。研究区长石、岩屑等矿物溶解作用强烈,溶蚀作用增加孔隙度平均为2.73%,最终孔隙度为11.70%。造成孔隙度损失的主要成岩作用为压实作用。%The scanning electron microscope( SEM),casting thin-sections and X-ray diffraction were used to ana-lyze the diagenesis and the porosity eVolution of the Chang 2 reserVoir in Resiwan oilfield,Ordos basin. The study suggests that Chang 2 reserVoir of Resiwan oilfield is the low-porosity and ultra-low permeability reserVoir type,the main pore types of the reserVoir are primary intergranular pores and secondary dissolution pores. The result of the e-Volution of porosity parameters indicates that the aVerage primary porosity is 35 . 29%. During the diagenesis process,the lost porosity of compaction and cementation are 22. 01% and 6. 40% respectiVely. Strong dissolution had been obserVed in study which added an aVerage porosity of 2 . 73%,making the final porosity increased to 11 . 90%. Compaction is the predominating cause of the porosity loss.

  17. Common File Formats.

    Mills, Lauren


    An overview of the many file formats commonly used in bioinformatics and genome sequence analysis is presented, including various data file formats, alignment file formats, and annotation file formats. Example workflows illustrate how some of the different file types are typically used.

  18. The Format Registry Problem

    Gary McGath


    Full Text Available File format identification is an important issue in digital preservation. Several noteworthy attempts, including PRONOM, GDFR, and UDFR, have been made at creating a comprehensive repository of format information. The sheer amount of information to cover and the constant introduction of new formats and format versions has limited their success. Alternative approaches, such as Linked Data and offering limited per-format information with identifiers that can be used elsewhere, may lead to greater success.

  19. Formate Formation and Formate Conversion in Biological Fuels Production

    Bryan R. Crable


    Full Text Available Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production.

  20. Simple Ontology Format (SOFT)


    Simple Ontology Format (SOFT) library and file format specification provides a set of simple tools for developing and maintaining ontologies. The library, implemented as a perl module, supports parsing and verification of the files in SOFt format, operations with ontologies (adding, removing, or filtering of entities), and converting of ontologies into other formats. SOFT allows users to quickly create ontologies using only a basic text editor, verify it, and portray it in a graph layout system using customized styles.

  1. The Quantitative Evaluation Index System for Uranium Reservoir Heterogeneity in Hantaimiao Region,Ordos Basin%鄂尔多斯盆地罕台庙地区铀储层非均质性定量怦价指标体系

    谢惠丽; 吴立群; 焦养泉; 荣辉; 汪洪强


    Uranium reservoir heterogeneity plays an important role in the process of uranium mineralization.However,people have not been recognized and need further study on the uranium reservoir heterogeneity of Hantaimiao region in Ordos Basin. By plane mapping and statistical analysis of quantitative heterogeneity parameters is study area,it shows that the heterogeneity of uranium reservoir sand body can be quantitatively characterized by sandstone thickness,sandstone percentage,sandstone grain size,number and cumulative thickness of clay isolated barrier beds,and original organic carbon content.It is found that uranium reservoir heterogeneity is weak at the central axis area of braided distributary channel sand body;and becomes strong at the both edges of the central axis area of sand body and the downstream area.Through the comprehensive analysis of the re-lationship between quantitative heterogeneity parameters and uranium mineralization information,uranium reservoir heteroge-neity is divided into class Ⅰ (weak),class Ⅱ (medium)and class Ⅲ (strong).The uranium mineralization in class Ⅱ reservoirs is the most active.And the quantitative evaluation index system for uranium reservoir heterogeneity,which is comprehensively evaluated by multi parameters,is established ultimately.It is generally held in previous qualitative research that uranium reser-voir heterogeneity controls uranium mineralization process and also affects the in-situ leaching uranium process.This quantita-tive evaluation index system will be able to predict more accurately the uranium target area and to optimize the proj ect deploy-ment of in-situ leaching uranium,improving the efficiency of the exploration and mining of uranium.%铀储层非均质性在铀成矿作用过程中发挥着重要作用,但人们对鄂尔多斯盆地罕台庙地区铀储层非均质性研究未见深入.该地区铀储层通过平面编图和统计分析,结果表明铀储层的砂体厚度、含砂率、砂岩粒度

  2. 鄂尔多斯盆地西南部山1、盒8段孔隙特征及物性研究%Research on Pore Characteristics and Petrophysical Properties of P1s1 and P1h8 Members in the Southwest of Ordos Basin

    汪远征; 黄文辉; 闫德宇; 王婷灏


    In recent years, area in the southwest of Ordos Basin has become the key blocks of exploration and development.Nevertheless, there are still insufficient studies on reservoir space and petrophysical properties of P1s1 and P1h8 Members in this area.According to the observation of polarizing microscope and scanning electron microscopy with mercury injection t data, detailed analysis has been made on the pore microscopic features and types, pore structure and petrophysical properties.Results indicate that the major pore types in the research area are residual intergranular pore, lithic dissolved pore, matrix dissolved pore and intercrystalline pore.Pore structure of the upper P1h8 Member is the best, followed by the lower P1h8 Member, and the pore structure of P1s1 Member is relatively poor, on the basis of pore-throat size,sorting and connectivity.Both P1s1 and P1h8 Members are low-permeability reservoirs.Porosity and permeability are in exponential correlation.The value of porosity and permea-bility of upper P1h8 Member is bigger than lower P1h8 Member.Obviously, porosity and permeability of P1h8 Member is superior to P1s1 Member.In general, petrophysical properties of the upper P1h8 Member is the best, followed by the lower P1h8 Member, but petrophysical properties of P1s1 Member is the worst.%近年来,鄂尔多斯盆地西南部逐渐成为致密气勘探开发的重点区块。然而,对该地区主力产气层山1段和盒8段的储集空间以及物性特征的研究还十分不足。利用偏光显微镜、扫描电镜观察,结合压汞实验数据,对研究区山1、盒8段砂岩的孔隙微观特征及类型、孔隙结构及物性关系进行了详细的分析。结果表明:研究区主要发育的孔隙类型为残余粒间孔、岩屑溶孔、杂基溶孔和晶间孔;孔喉大小、分选性以及连通性的分析显示,盒8上亚段的孔隙结构最好,其次为盒8下亚段,山1段的孔隙结构相对较差;山1段和盒8段

  3. 冷季暖棚对鄂尔多斯细毛羊体重及产毛性能影响的研究%Influence of Warm Shed Feeding Manner on Weight and Wool Production Performance of Ordos Fine Wool Sheep in Cold Season

    谷英; 斯登丹巴; 姚江勇; 满都拉; 浪腾; 徐忠林; 王玮; 郑建峰


    为评价冷季暖棚饲养方式对鄂尔多斯细毛羊体重及产毛性能的影响,将选取的基础母羊、后备母羊、育成母羊、育成公羊分别随机分成试验组和对照组。各试验组于2012年12月7日—2013年1月31日,夜间圈入暖棚内饲养,对照组夜间在圈外饲养。记录冷季暖棚试验期间暖棚内、外夜间气温,比较各试验组及对照组在冷季暖棚试验期间的体重变化。冷季暖棚试验结束后,试验羊只继续饲喂至2013年6月初。试验结束时,分别测定并比较基础母羊、后备母羊、育成母羊的试验组及对照组产毛量、羊毛长度、羊毛细度。结果表明,冷季暖棚试验期内,圈内、外夜间平均气温相差9.76℃,圈内、外最低气温相差14.10℃;基础母羊、后备母羊、育成母羊试验组体重分别比对照组少下降3.57、2.98、2.74 kg,育成公羊试验组体重比照组多提高3.08 kg;基础母羊、后备母羊、育成母羊的试验组产毛量分别比对照组增加0.22 kg(P>0.05)、0.11 kg(P0.05);基础母羊、后备母羊、育成母羊的试验组羊毛长度分别比对照组增加0.40 cm(P>0.05)、0.31 cm(P>0.05)、0.25 cm(P>0.05);基础母羊、后备母羊、育成母羊试验组羊毛细度均比对照组细,且细度分别降低了0.01μm(P>0.05)、0.09μm(P>0.05)、0.24μm(P>0.05)。结果提示,冷季暖棚饲养方式可有效防止鄂尔多斯细毛羊掉膘,并可提高产毛量,增加羊毛长度,降低羊毛细度。%In order to evaluate the influence of warm shed feeding manner on weight and wool production performance of Ordos fine wool sheep in cold season, the selected basic ewe, reserved ewe, gimmer hogg and ram hogg were randomly divided into experimental group and control group, respectively. All of the experimental groups fed inside the warm shed at night from December 7 of 2012 to January 31 of 2013, whereas the control

  4. Research on reservoirs characteristics of 8th member of YanAN formation,NingDong 3 well field,MaHuangShan area,Ordos basin%鄂尔多斯盆地麻黄山地区宁东3井区延8段储层特征研究

    吴(山交)岐; 张哨楠; 丁晓琪



  5. Star Formation for Predictive Primordial Galaxy Formation

    Milosavljević, Miloš; Safranek-Shrader, Chalence

    The elegance of inflationary cosmology and cosmological perturbation theory ends with the formation of the first stars and galaxies, the initial sources of light that launched the phenomenologically rich process of cosmic reionization. Here we review the current understanding of early star formation, emphasizing unsolved problems and technical challenges. We begin with the first generation of stars to form after the Big Bang and trace how they influenced subsequent star formation. The onset of chemical enrichment coincided with a sharp increase in the overall physical complexity of star forming systems. Ab-initio computational treatments are just now entering the domain of the predictive and are establishing contact with local observations of the relics of this ancient epoch.

  6. Formation Flying Concept Issues

    M. V. Palkin


    Full Text Available The term “formation flying” implies coordinated movement of at least two satellites on coplanar and non-coplanar orbits with a maximum distance between them being much less than the length of the orbit. Peculiarities of formation flying concept also include:- automatic coordination of satellites;- sub-group specialization of formation flying satellites;- equipment and data exchange technology unification in each specialized group or subgroup.Formation flying satellites can be classified according to the configuration stability level (order (array, cluster («swarm», intergroup specialization rules («central satellite», «leader», «slave», manoeuvrability («active» and «passive» satellites.Tasks of formation flying include:- experiments with payload, distributed in formation flying satellites;- various near-earth space and earth-surface research;- super-sized aperture antenna development;- land-based telescope calibration;- «space advertisement» (earth-surface observable satellite compositions of a logotype, word, etc.;- orbital satellite maintenance, etc.Main issues of formation flying satellite system design are:- development of an autonomous satellite group manoeuvring technology;- providing a sufficient characteristic velocity of formation flying satellites;- ballistic and navigation maintenance for satellite formation flying;- technical and economic assessment of formation flying orbital delivery and deployment;- standardization, unification, miniaturization and integration of equipment;- intergroup and intersatellite function redistribution.

  7. The Conic Benchmark Format

    Friberg, Henrik A.

    This document constitutes the technical reference manual of the Conic Benchmark Format with le extension: .cbf or .CBF. It unies linear, second-order cone (also known as conic quadratic) and semidenite optimization with mixed-integer variables. The format has been designed with benchmark libraries...... in mind, and therefore focuses on compact and easily parsable representations. The problem structure is separated from the problem data, and the format moreover facilitate benchmarking of hotstart capability through sequences of changes....

  8. Formative Assessment in Context

    Oxenford-O'Brian, Julie


    This dissertation responds to critical gaps in current research on formative assessment practice which could limit successful implementation of this practice within the K-12 classroom context. The study applies a socio cultural perspective of learning to interpret a cross-case analysis of formative assessment practice occurring during one…

  9. Formation of multiple networks

    Magnani, Matteo; Rossi, Luca


    we introduce the first network formation model for multiple networks. Network formation models are among the most popular tools in traditional network studies, because of both their practical and theoretical impact. However, existing models are not sufficient to describe the generation of multiple...

  10. Isothermal Martensite Formation

    Villa, Matteo

    Isothermal (i.e. time dependent) martensite formation in steel was first observed in the 40ies of the XXth century and is still treated as an anomaly in the description of martensite formation which is considered as a-thermal (i.e. independent of time). Recently, the clarification of the mechanis...

  11. Galaxy Formation Theory

    Benson, Andrew J


    We review the current theory of how galaxies form within the cosmological framework provided by the cold dark matter paradigm for structure formation. Beginning with the pre-galactic evolution of baryonic material we describe the analytical and numerical understanding of how baryons condense into galaxies, what determines the structure of those galaxies and how internal and external processes (including star formation, merging, active galactic nuclei etc.) determine their gross properties and evolution. Throughout, we highlight successes and failings of current galaxy formation theory. We include a review of computational implementations of galaxy formation theory and assess their ability to provide reliable modeling of this complex phenomenon. We finish with a discussion of several "hot topics" in contemporary galaxy formation theory and assess future directions for this field.

  12. Usage Record Format Recommendation

    Nilsen, J.K.; Muller-Pfeerkorn, R


    For resources to be shared, sites must be able to exchange basic accounting and usage data in a common format. This document describes a common format which enables the exchange of basic accounting and usage data from different resources. This record format is intended to facilitate the sharing of usage information, particularly in the area of the accounting of jobs, computing, memory, storage and cloud usage but with a structure that allows an easy extension to other resources. This document describes the Usage Record components both in natural language form and annotated XML. This document does not address how these records should be used, nor does it attempt to dictate the format in which the accounting records are stored. Instead, it denes a common exchange format. Furthermore, nothing is said regarding the communication mechanisms employed to exchange the records, i.e. transport layer, framing, authentication, integrity, etc.

  13. When efficient star formation drives cluster formation

    Parmentier, G


    We investigate the impact of the star formation efficiency in cluster forming cores on the evolution of the mass in star clusters over the age range 1-100Myr, when star clusters undergo their infant weight-loss/mortality phase. Assuming a constant formation rate of gas-embedded clusters and a weak tidal field, we show that the ratio between the total mass in stars bound to the clusters over that age range and the total mass in stars initially formed in gas-embedded clusters is a strongly increasing function of the averaged local SFE, with little influence from any assumed core mass-radius relation. Our results suggest that, for young starbursts with estimated tidal field strength and known recent star formation history, observed cluster-to-star mass ratios, once corrected for the undetected clusters, constitute promising probes of the local SFE, without the need of resorting to gas mass estimates. Similarly, the mass ratio of stars which remain in bound clusters at the end of the infant mortality/weight-loss ...

  14. 鄂尔多斯市1988-2000年土壤水力侵蚀与土地利用时空变化关系%The Temporal and Spatial Variability Relationship of Soil Water Erosion and Land Use Type in Ordos during the Period of 1988-2000

    周平; 蒙吉军


    土地利用是引起土壤侵蚀的重要驱动过程.基于1988年和2000年TM影像数据和气候、土壤、植被及DEM等数据,运用通用的土壤流失预报方程(RUSLE),对鄂尔多斯市1988-2000年间的土壤水力侵蚀进行定量估算,揭示期间水力侵蚀的时空变化特点,并对土地利用类型与土壤侵蚀的关系进行分析.结果显示:1988-2000年间,研究区土壤水力侵蚀时空变化较为明显.时间变化上侵蚀强度明显减弱,除了微度侵蚀从53.16%剧增至81.24%以外,中度、强度、极强度和剧烈侵蚀类型均有较大幅度的下降;空间变化亦很明显,2000年与1988年相比,剧烈侵蚀只有准格尔旗东南部还有少量分布,强度侵蚀和极强度侵蚀主要分布在准格尔旗境内.土地利用方式对土壤侵蚀有明显的影响,高覆盖度草地和水域的土壤侵蚀强度较小.此外,不同土地利用类型的平均土壤侵蚀模数和土壤强度指数均有大幅度的下降.其中未利用地的下降幅度最大(68.14%),其次为低覆盖度草地(64.09%),耕地的下降幅度最小(49.62%).研究结果表明,鄂尔多斯土壤水力侵蚀治理的重点区域是东北部,改变土地利用方式、增加水土保持工程措施、加强采矿迹地的修复重建等是有效防治土壤水力侵蚀的重要措施.%Land use is an important cause of soil erosion process. Based on the TM image data, climate, soil, vegetation and DEM data etc. in 1988 and 2000, this paper used the Revised Universal Soil Loss Equation (RUSLE) to estimate the amount of soil water erosion of Ordos city which was located in the farming-grazing transitional zone during the period of 1988 - 2000 and revealed the characteristics of temporal and spatial variability of soil water erosion and then analyzed the relationship between land use types and soil water erosion. The results showed; in 1988 the average soil erosion modulus was 2772. 07 t/(km~2 · a) and in 2000 the average soil erosion

  15. Methemoglobin formation by paraquat.



    Full Text Available Paraquat is a broad spectrum herbicide known to be highly lethal to man and animals. Its toxicity is characterized by acute lung injury. Paraquat produces such toxic effects through the generation of the superoxide anion according to one proposed mechanism. The present experiment, methemoglobin formation was demonstrated after incubation of oxyhemoglobin with paraquat. The generation of the superoxide anion through the interaction of oxyhemoglobin with paraquat was suggested by chemiluminescence of luminol. Superoxide dismutase (SOD and catalare inhibited methemoglobin formation. The generation of the superoxide anion is discussed in regard to methemoglobin formation by paraquat.

  16. Challenges in Planet Formation

    Morbidelli, Alessandro


    Over the past two decades, large strides have been made in the field of planet formation. Yet fundamental questions remain. Here we review our state of understanding of five fundamental bottlenecks in planet formation. These are: 1) the structure and evolution of protoplanetary disks; 2) the growth of the first planetesimals; 3) orbital migration driven by interactions between proto-planets and gaseous disk; 4) the origin of the Solar System's orbital architecture; and 5) the relationship between observed super-Earths and our own terrestrial planets. Given our lack of understanding of these issues, even the most successful formation models remain on shaky ground.

  17. Manuel UNIMARC format bibliographique


    This manual is the French translation of the second edition of UNIMARC Manual: bibliographic format published in English in 1994 and completed by 5 updates published from 1996 to 2005. This 5th French edition is composite. It reproduces identically a part of the 4th edition published in 2002 and, for the fields of the format modified in the Update 5, it offers a new more structured presentation. This is a handbook dedicated to French-speaking users of the UNIMARC format for bibliographic descriptions.

  18. Pictorial Formats. Volume 1. Format Development


    the pilot to help him evaluate when to change course to avoid objects in TF/TA modes. In addition to the projected flight path, there are commanded...TYPESFigMASTER5 Wepo Saus clr ase 00I 16I AI 󈧋TRA- X PI prI MEN p~ll It 62 AIR-TO-GROUND _ - PRGRAM ýRELEASE SELECTIONS _ZY - Figure 58 71T ý Weapon...development should always be done within the context oF a baseline aircraft weapon system. Further studies are needed to simulate and evaluate these formats

  19. Notes on Star Formation

    Krumholz, Mark R


    This book provides an introduction to the field of star formation at a level suitable for graduate students or advanced undergraduates in astronomy or physics. The structure of the book is as follows. The first two chapters begin with a discussion of observational techniques, and the basic phenomenology they reveal. The goal is to familiarize students with the basic techniques that will be used throughout, and to provide a common vocabulary for the rest of the book. The next five chapters provide a similar review of the basic physical processes that are important for star formation. Again, the goal is to provide a basis for what follows. The remaining chapters discuss star formation over a variety of scales, starting with the galactic scale and working down to the scales of individual stars and their disks. The book concludes with a brief discussion of the clearing of disks and the transition to planet formation. The book includes five problem sets, complete with solutions.


    has been determined spectrophotometrically for 1:1 complex formation at ... DFT has been extensively used due to their accuracy and low computational cost .... Our input data for analysis of metal-ligand system were absorbance of 50 different.

  1. Collision Induced Galaxy Formation

    Balland, C; Schäffer, R


    We present a semi-analytical model in which galaxy collisions and strong tidal interactions, both in the field and during the collapse phase of groups and clusters help determine galaxy morphology. From a semi-analytical analysis based on simulation results of tidal collisions (Aguilar & White 1985), we propose simple rules for energy exchanges during collisions that allow to discriminate between different Hubble types: efficient collisions result in the disruption of disks and substantial star formation, leading to the formation of elliptical galaxies; inefficient collisions allow a large gas reservoir to survive and form disks. Assuming that galaxy formation proceeds in a Omega_0=1 Cold Dark Matter universe, the model both reproduces a number of observations and makes predictions, among which are the redshifts of formation of the different Hubble types in the field. When the model is normalized to the present day abundance of X-ray clusters, the amount of energy exchange needed to produce elliptical gal...

  2. Coalition Formation under Uncertainty


    Unfortunately, many current approaches to coalition formation lack provi- sions for uncertainty. This prevents application of coalition formation techniques ...should also include mechanisms and processing techniques that provide stabil- ity, scalability, and, at a minimum, optimality relative to agent beliefs...relocate a piano . For the sake of simplicity, assume payment is divided evenly among the participants in the move (i.e., each mover has the same utility or

  3. PCF File Format.

    Thoreson, Gregory G [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    PCF files are binary files designed to contain gamma spectra and neutron count rates from radiation sensors. It is the native format for the GAmma Detector Response and Analysis Software (GADRAS) package [1]. It can contain multiple spectra and information about each spectrum such as energy calibration. This document outlines the format of the file that would allow one to write a computer program to parse and write such files.

  4. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

    Emmerling, Uwe; Rasmussen, Peter


    Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated usi...

  5. Formation peculiarities of tourism documentation

    Zhezhnych, Pavlo; Soprunyuk, Oksana


    The article describes formation peculiarities of tourism documentation, the role of tourism data consolidation for unified format creation and the the need to use existing software tools to handle tourism information, formation process of tourism documentation is presented.

  6. Situated Formative Feedback

    Lukassen, Niels Bech; Wahl, Christian; Sorensen, Elsebeth Korsgaard


    This study addresses the conceptual challenge of providing students with good quality feedback to enhance student learning in an online community of practice (COP). The aim of the study is to identify feedback mechanisms in a virtual learning environment (VLE) and to create a full formative...... feedback episode (FFE) through an online dialogue. The paper argues that dialogue is crucial for student learning and that feedback is not only something the teacher gives to the student. Viewing good quality feedback as social, situated, formative, emphasis is put on the establishment of dialogue. We...... refer to this type of feedback as, Situated Formative Feedback (SFF). As a basis for exploring, identifying and discussing relevant aspects of SFF the paper analyses qualitative data from a Moodle dialogue. Data are embedded in the qualitative analytic program Nvivo and are analysed with a system...

  7. Forces in strategy formation

    Steensen, Elmer Fly


    This chapter proposes that organizational strategy formation should be characterized theoretically as a process that is subject to several interacting forces, rather than represented by separate discrete decisionmodels or theoretic perspectives, as is commonly done in the strategic management...... literature. Based on an extensive review of relevant theory and empirical work in strategic decision-making, organizational change theory, cognitive and social psychology, and strategy processes, seven kinds of ''forces'' - rational, imposed, teleological, learning, political, heuristic, and social...... - are identified as interacting in and having significant influence on the strategy formation process. It is further argued that by applying a holistic ''forces-view'' of the significant and interacting influences on strategy formation, we can better understand the dynamics and challenges in managing the process...

  8. Meningococcal biofilm formation

    Lappann, M.; Haagensen, Janus Anders Juul; Claus, H.


    We show that in a standardized in vitro flow system unencapsulated variants of genetically diverse lineages of Neisseria meningitidis formed biofilms, that could be maintained for more than 96 h. Biofilm cells were resistant to penicillin, but not to rifampin or ciprofloxacin. For some strains......, microcolony formation within biofilms was observed. Microcolony formation in strain MC58 depended on a functional copy of the pilE gene encoding the pilus subunit pilin, and was associated with twitching of cells. Nevertheless, unpiliated pilE mutants formed biofilms showing that attachment and accumulation......X alleles was identified among genetically diverse meningococcal strains. PilX alleles differed in their propensity to support autoaggregation of cells in suspension, but not in their ability to support microcolony formation within biofilms in the continuous flow system....

  9. Kuiper Binary Object Formation

    Nazzario, R C; Covington, C; Kagan, D; Hyde, T W


    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction between the KBOs and the third body causes one of four effects; scattering into the Oort cloud, collisions with the growing protoplanets, formation of binary pairs, or creation of a single Kuiper belt object. Additionally, the initial location of the progenitors of the Kuiper belt objects also has a significant effect on binary formation.

  10. Primordial Planet Formation

    Schild, Rudolph E


    Recent spacecraft observations exploring solar system properties impact standard paradigms of the formation of stars, planets and comets. We stress the unexpected cloud of microscopic dust resulting from the DEEP IMPACT mission, and the existence of molten nodules in STARDUST samples. And the theory of star formation does not explain the common occurrence of binary and multiple star systems in the standard gas fragmentation scenario. No current theory of planet formation can explain the iron core of the earth, under oceans of water. These difficulties are avoided in a scenario where the planet mass objects form primordially and are today the baryonic dark matter. They have been detected in quasar microlensing and anomalous quasar radio brightening bursts. The primordial planets often concentrate together to form a star, with residual matter seen in pre-stellar accretion discs around the youngest stars. These primordial planet mass bodies were formed of hydrogen-helium, aggregated in dense clumps of a trillion...

  11. Meningococcal biofilm formation

    Lappann, M.; Haagensen, Janus Anders Juul; Claus, H.


    We show that in a standardized in vitro flow system unencapsulated variants of genetically diverse lineages of Neisseria meningitidis formed biofilms, that could be maintained for more than 96 h. Biofilm cells were resistant to penicillin, but not to rifampin or ciprofloxacin. For some strains......, microcolony formation within biofilms was observed. Microcolony formation in strain MC58 depended on a functional copy of the pilE gene encoding the pilus subunit pilin, and was associated with twitching of cells. Nevertheless, unpiliated pilE mutants formed biofilms showing that attachment and accumulation......X alleles was identified among genetically diverse meningococcal strains. PilX alleles differed in their propensity to support autoaggregation of cells in suspension, but not in their ability to support microcolony formation within biofilms in the continuous flow system....

  12. Syntactic Formats for Free

    Klin, Bartek; Sobocinski, Pawel


    A framework of Plotkin and Turi’s, originally aimed at providing an abstract notion of bi-simulation, is modified to cover other operational equivalences and preorders. Combined with bi-algebraic methods, it yields a technique for the derivation of syntactic formats for transition system specific......A framework of Plotkin and Turi’s, originally aimed at providing an abstract notion of bi-simulation, is modified to cover other operational equivalences and preorders. Combined with bi-algebraic methods, it yields a technique for the derivation of syntactic formats for transition system...... specifications which guarantee operational preorders to be precongruences. The technique is applied to the trace preorder, the completed trace pre order and the failures preorder. In the latter two cases, new syntactic formats ensuring precongruence properties are introduced....

  13. The format of things

    Jørnø, Rasmus Leth

    or surpasses speech and writing. The well from which we draw our design ideas for novel interfaces is therefore needlessly restricted by a format that has outlived its purpose. The objective of the thesis is to dismantle the format of things as well as to sketch out novel paths of inquiry for new interfaces...... ontological biases and epistemological assumptions which, to a great extent, delimit what can be thought about interfaces and shorten the imaginative horizon. The objective of this thesis is to break the hegemony of a particular type of understanding of the world and interfaces, and to make new approaches...

  14. Isolating Triggered Star Formation

    Barton, Elizabeth J.; Arnold, Jacob A.; /UC, Irvine; Zentner, Andrew R.; /KICP, Chicago /Chicago U., EFI; Bullock, James S.; /UC, Irvine; Wechsler, Risa H.; /KIPAC, Menlo


    Galaxy pairs provide a potentially powerful means of studying triggered star formation from galaxy interactions. We use a large cosmological N-body simulation coupled with a well-tested semi-analytic substructure model to demonstrate that the majority of galaxies in close pairs reside within cluster or group-size halos and therefore represent a biased population, poorly suited for direct comparison to 'field' galaxies. Thus, the frequent observation that some types of galaxies in pairs have redder colors than 'field' galaxies is primarily a selection effect. We use our simulations to devise a means to select galaxy pairs that are isolated in their dark matter halos with respect to other massive subhalos (N= 2 halos) and to select a control sample of isolated galaxies (N= 1 halos) for comparison. We then apply these selection criteria to a volume-limited subset of the 2dF Galaxy Redshift Survey with M{sub B,j} {le} -19 and obtain the first clean measure of the typical fraction of galaxies affected by triggered star formation and the average elevation in the star formation rate. We find that 24% (30.5 %) of these L* and sub-L* galaxies in isolated 50 (30) h{sup -1} kpc pairs exhibit star formation that is boosted by a factor of {approx}> 5 above their average past value, while only 10% of isolated galaxies in the control sample show this level of enhancement. Thus, 14% (20 %) of the galaxies in these close pairs show clear triggered star formation. Our orbit models suggest that 12% (16%) of 50 (30) h{sup -1} kpc close pairs that are isolated according to our definition have had a close ({le} 30 h{sup -1} kpc) pass within the last Gyr. Thus, the data are broadly consistent with a scenario in which most or all close passes of isolated pairs result in triggered star formation. The isolation criteria we develop provide a means to constrain star formation and feedback prescriptions in hydrodynamic simulations and a very general method of understanding

  15. Sensitivity Data File Formats

    Rearden, Bradley T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    The format of the TSUNAMI-A sensitivity data file produced by SAMS for cases with deterministic transport solutions is given in Table 6.3.A.1. The occurrence of each entry in the data file is followed by an identification of the data contained on each line of the file and the FORTRAN edit descriptor denoting the format of each line. A brief description of each line is also presented. A sample of the TSUNAMI-A data file for the Flattop-25 sample problem is provided in Figure 6.3.A.1. Here, only two profiles out of the 130 computed are shown.

  16. Formation of Saturn's spokes

    Goertz, C. K.


    The theoretical requirements of the Goertz and Morfill (1983) model of the formation of spokes in the rings of Saturn are analyzed. Consideration is given to model predictions of dust particle size distribution, the optical depth of the spokes, and the radial speed of spoke evolution. It is shown that the electrostatic levitation of singly charged dust particles would be sufficient to cause the spokes to form. The maximum formation time for spokes of more than 10,000 km radial length is estimated to be less than five minutes. Observations of the scattering properties of the spokes showed general agreement with the theoretical calculations.

  17. The formation of stars

    Stahler, Steven W


    This book is a comprehensive treatment of star formation, one of the most active fields of modern astronomy. The reader is guided through the subject in a logically compelling manner. Starting from a general description of stars and interstellar clouds, the authors delineate the earliest phases of stellar evolution. They discuss formation activity not only in the Milky Way, but also in other galaxies, both now and in the remote past. Theory and observation are thoroughly integrated, with the aid of numerous figures and images. In summary, this volume is an invaluable resource, both as a text f

  18. Tea aroma formation

    Chi-Tang Ho


    Full Text Available Besides water, tea is one of the most popular beverages around the world. The chemical ingredients and biological activities of tea have been summarized recently. The current review summarizes tea aroma compounds and their formation in green, black, and oolong tea. The flavor of tea can be divided into two categories: taste (non-volatile compounds and aroma (volatile compounds. All of these aroma molecules are generated from carotenoids, lipids, glycosides, etc. precursors, and also from Maillard reaction. In the current review, we focus on the formation mechanism of main aromas during the tea manufacturing process.

  19. Shape formation algorithm


    This project concerns the implementation of a decentralized algorithm for shape formation. The first idea was to test this algorithm with a swarm of autonomous drones but, due to the lack of time and the complexity of the project, the work was just developed in 2D and in simulation.

  20. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted

  1. PAHs and star formation

    Tielens, AGGM; Peeters, E; Bakes, ELO; Spoon, HWW; Hony, S; Johnstone, D; Adams, FC; Lin, DNC; Neufeld, DA; Ostriker, EC


    Strong IR emission features at 3.3, 6.2, 7.7, 8.6, and 11.2 mum are a common characteristic of regions of massive star formation. These features are carried by large (similar to 50 C-atom) Polycyclic Aromatic Hydrocarbon molecules which are pumped by the strong FUV photon flux from these stars. Thes

  2. BISAC Variable Format.

    Information Technology and Libraries, 1983


    Presents revision of Book Industry Systems Advisory Committee (BISAC) format designed specifically for electronic transmission of purchase orders for monograph or series titles combining fixed and variable length data fields which was approved in January 1983. Special characters, sample address descriptions, summary of fixed records, glossary, and…

  3. Kepler Planet Formation

    Lissauer, Jack J.


    Kepler has vastly increased our knowledge of planets and planetary systems located close to stars. The new data shows surprising results for planetary abundances, planetary spacings and the distribution of planets on a mass-radius diagram. The implications of these results for theories of planet formation will be discussed.

  4. Determinants for gallstone formation

    Shabanzadeh, Daniel Monsted; Sorensen, Lars Tue; Jørgensen, Torben


    associations were found for blood pressure, smoking, alcohol consumption, HDL cholesterol, or triglycerides in meta-analyses. Conclusions: Age, female sex, BMI, non-HDL cholesterol, and polyps are independent determinants for gallstone formation. Incident gallstones and the metabolic syndrome share common risk...

  5. Cosmic structure formation

    Bertschinger, Edumund


    This article reviews the prevailing paradigm for how galaxies and larger structures formed in the universe: gravitational instability. Basic observational facts are summarized to motivate the standard cosmological framework underlying most detailed investigations of structure formation. The observed univers approaches spatial uniformity on scales larger than about 10(exp 26) cm. On these scales gravitational dynamics is almost linear and therefore relatively easy to relate to observations of large-scale structure. On smaller scales cosmic structure is complicated not only by nonlinear gravitational clustering but also by nonlinear nongravitational gas dynamical processes. The complexity of these phenomena makes galaxy formation one of the grand challenge problems of the physical sciences. No fully satisfactory theory can presently account in detail for the observed cosmic structure. However, as this article summarizes, significant progress has been made during the last few years.

  6. Formation of bacterial nanocells

    Vainshtein, Mikhail; Kudryashova, Ekaterina; Suzina, Natalia; Ariskina, Elena; Voronkov, Vadim


    Existence of nanobacteria received increasing attention both in environmental microbiology/geomicro-biology and in medical microbiology. In order to study a production of nanoforms by typical bacterial cells. Effects of different physical factors were investigated. Treatment of bacterial cultures with microwave radiation, or culturing in field of electric current resulted in formation a few types of nanocells. The number and type of nanoforms were determined with type and dose of the treatment. The produced nanoforms were: i) globules, ii) clusters of the globules--probably produced by liaison, iii) nanocells coated with membrane. The viability of the globules is an object opened for doubts. The nanocells discovered multiplication and growth on solidified nutrient media. The authors suggest that formation of nanocells is a common response of bacteria to stress-actions produced by different agents.

  7. Un dilemme de formation

    Fields, Marjorie; Marvel, David


    Le Master of Art in Teaching prépare à l’enseignement dans l’État de l’Alaska en un an. Les candidats doivent faire preuve d’un bon niveau dans leur discipline pour avoir accès à la formation qui comprend des études théoriques et des stages. Un système d’évaluation de l’enseignant stagiaire et de l’enseignant en fonction permet d’améliorer et de faire évoluer constamment cette formation. Les objectifs de compétence présentés étonneront plus d’un lecteur européen. The Master of Arts in Teac...

  8. Emptiness Formation Probability

    Crawford, Nicholas; Ng, Stephen; Starr, Shannon


    We present rigorous upper and lower bounds on the emptiness formation probability for the ground state of a spin-1/2 Heisenberg XXZ quantum spin system. For a d-dimensional system we find a rate of decay of the order {exp(-c L^{d+1})} where L is the sidelength of the box in which we ask for the emptiness formation event to occur. In the {d=1} case this confirms previous predictions made in the integrable systems community, though our bounds do not achieve the precision predicted by Bethe ansatz calculations. On the other hand, our bounds in the case {d ≥ 2} are new. The main tools we use are reflection positivity and a rigorous path integral expansion, which is a variation on those previously introduced by Toth, Aizenman-Nachtergaele and Ueltschi.

  9. Simulating Cosmic Structure Formation

    Weinberg, D H; Hernquist, L E; Weinberg, David H.; Katz, Neal; Hernquist, Lars


    We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body simulations with Gaussian initial conditions produce a pattern of sheets, filaments, tunnels, and voids that resembles the observed large scale galaxy distribution. Simulations that incorporate gas dynamics and dissipation form dense clumps of cold gas with sizes and masses similar to the luminous parts of galaxies. Models based on inflation and cold dark matter predict a healthy population of high redshift galaxies, including systems with star formation rates of 20 M_{\\sun}/year at z=6. At z~3, most of the baryons in these models reside in the low density intergalactic medium, which produces fluctuating Lyman-alpha absorption in the spectra of background quasars. The physical description of this ``Lyman-alpha forest'' is particularly simple if the absorption spectrum is viewe...

  10. Formatting Design Dialogues

    Brandt, Eva; Binder, Thomas; Messeter, Jörn


    in collaborative settings and finally we examine the board game as a particularly interesting game format. In the second part of the article we present and discuss two board games: the User Game and the Landscape Game. We show how these games respond to particular challenges, and how they have interesting......This article discusses design games as a particular genre for formatting design dialogues. In the first part of the article we review the participatory design literature for game-oriented framings of co-design. We look at what constitutes game and play, we discuss other authors’ use of games...... characteristics in being both ‘as-if’ worlds to explore and shared representations of what the players accomplish. In the last section of the article we discuss how new games may be designed and played and what makes a good design game....

  11. Situated Formative Feedback

    Lukassen, Niels Bech; Wahl, Christian; Sorensen, Elsebeth Korsgaard


    feedback episode (FFE) through an online dialogue. The paper argues that dialogue is crucial for student learning and that feedback is not only something the teacher gives to the student. Viewing good quality feedback as social, situated, formative, emphasis is put on the establishment of dialogue. We...... refer to this type of feedback as, Situated Formative Feedback (SFF). As a basis for exploring, identifying and discussing relevant aspects of SFF the paper analyses qualitative data from a Moodle dialogue. Data are embedded in the qualitative analytic program Nvivo and are analysed with a system...... theoretical textual analysis method. Asynchronous written dialogue from an online master’s course at Aalborg University forms the empirical basis of the study. The findings suggests in general that students play an essential role in SFF and that students and educators are equal in the COP, but holds different...

  12. Kuiper Binary Object Formation

    Nazzario, R. C.; Orr, K.; Covington, C.; Kagan, D.; Hyde, T. W.


    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction betw...

  13. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:

  14. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet

  15. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet

  16. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:

  17. Formate-assisted pyrolysis

    DeSisto, William Joseph; Wheeler, Marshall Clayton; van Heiningen, Adriaan R. P.


    The present invention provides, among other thing, methods for creating significantly deoxygenated bio-oils form biomass including the steps of providing a feedstock, associating the feedstock with an alkali formate to form a treated feedstock, dewatering the treated feedstock, heating the dewatered treated feedstock to form a vapor product, and condensing the vapor product to form a pyrolysis oil, wherein the pyrolysis oil contains less than 30% oxygen by weight.

  18. Frost formation with salt

    Guadarrama-Cetina, J.; Mongruel, A; González-Viñas, W; Beysens, D. A.


    The formation of frost in presence of salt (NaCl) crystal is experimentally investigated on a hydrophobic surface. It presents several remarkable features due to the interplay of salty-water saturation pressure evolution, initially lower than the saturation pressure of ice and water, and the percolating propagation of ice dendrites from defects throughout the supercooled water droplet pattern. In particular, it is remarkable that nucleation of supercooled water and/or ice is prevented around ...

  19. Formate-assisted pyrolysis

    DeSisto, William Joseph; Wheeler, Marshall Clayton; van Heiningen, Adriaan R. P.


    The present invention provides, among other thing, methods for creating significantly deoxygenated bio-oils form biomass including the steps of providing a feedstock, associating the feedstock with an alkali formate to form a treated feedstock, dewatering the treated feedstock, heating the dewatered treated feedstock to form a vapor product, and condensing the vapor product to form a pyrolysis oil, wherein the pyrolysis oil contains less than 30% oxygen by weight.

  20. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows GB/T 7714—2005.The citation should be ordered in number as it appears in the text of the submitted article.For journal article Sun,Y.,Li,B.,&Qu,J.F.Design and implementation of library intelligent IM reference robot.New Technology of Library and Information Service(in Chinese),2011,205:88–92.

  1. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows GB/T 7714—2005.The citation should be ordered in number as it appears in the text of the submitted article.For journal article Sun,Y.,Li,B.,&Qu,J.F.Design and implementation of library intelligent IM reference robot.New Technology of Library and Information Service(in Chinese),

  2. Understanding Alliance Formation Patterns


    agreement to open international markets because trade produces security externalities.”131 Gowa explains the necessity to maintain trade among allies by...alone.”135 They present empirical evidence to “ indicate that allies conduct more trade than do non-allies and that the formation of alliances tends to...states to control their trade flows.”138 Morrow et al. indicate that “joint democracy and the 133

  3. Galaxy Formation and Evolution

    Nagamine, Kentaro; Reddy, Naveen; Daddi, Emanuele; Sargent, Mark T.


    In this chapter, we discuss the current status of observational and computational studies on galaxy formation and evolution. In particular, a joint analysis of star-formation rates (SFRs), stellar masses, and metallicities of galaxies throughout cosmic time can shed light on the processes by which galaxies build up their stellar mass and enrich the environment with heavy elements. Comparison of such observations and the results of numerical simulations can give us insights on the physical importance of various feedback effects by supernovae and active galactic nuclei. In Sect. 1, we first discuss the primary methods used to deduce the SFRs, stellar masses, and (primarily) gas-phase metallicities in high-redshift galaxies. Then, we show how these quantities are related to each other and evolve with time. In Sect. 2, we further examine the distribution of SFRs in galaxies following the `Main Sequence' paradigm. We show how the so-called `starbursts' display higher specific SFRs and SF efficiencies by an order of magnitude. We use this to devise a simple description of the evolution of the star-forming galaxy population since z ˜3 that can successfully reproduce some of the observed statistics in the infrared (IR) wavelength. We also discuss the properties of molecular gas. In Sect. 3, we highlight some of the recent studies of high-redshift galaxy formation using cosmological hydrodynamic simulations. We discuss the physical properties of simulated galaxies such as luminosity function and escape fraction of ionizing photons, which are important statistics for reionization of the Universe. In particular the escape fraction of ionizing photons has large uncertainties, and studying gamma-ray bursts (which is the main topic of this conference) can also set observational constraints on this uncertain physical parameter as well as cosmic star formation rate density.

  4. Tritiated ammonia formation

    Heung, L.K.


    A rate equation that closely simulates experimental data has been developed. this rate equation can be used to calculate the formation of tritiated ammonia from different concentrations of tritium and nitrogen. The reaction of T{sub 2} and N{sub 2} to form NT{sub 3} is a slow process, particularly when the tritium concentration is low. The reaction requires weeks or months to reach equilibrium dependent on the concentrations of the reactants.

  5. Formation of transient lamellipodia.

    Juliane Zimmermann

    Full Text Available Cell motility driven by actin polymerization is pivotal to the development and survival of organisms and individual cells. Motile cells plated on flat substrates form membrane protrusions called lamellipodia. The protrusions repeatedly appear and retract in all directions. If a lamellipodium is stabilized and lasts for some time, it can take over the lead and determine the direction of cell motion. Protrusions traveling along the cell perimeter have also been observed. Their initiation is in some situations the effect of the dynamics of the pathway linking plasma membrane receptors to actin filament nucleation, e.g. in chemotaxis. However, lamellipodia are also formed in many cells incessantly during motion with a constant state of the signaling pathways upstream from nucleation promoting factors (NPFs, or spontaneously in resting cells. These observations strongly suggest protrusion formation can also be a consequence of the dynamics downstream from NPFs, with signaling setting the dynamic regime but not initiating the formation of individual protrusions. A quantitative mechanism for this kind of lamellipodium dynamics has not been suggested yet. Here, we present a model exhibiting excitable actin network dynamics. Individual lamellipodia form due to random supercritical filament nucleation events amplified by autocatalytic branching. They last for about 30 seconds to many minutes and are terminated by filament bundling, severing and capping. We show the relevance of the model mechanism for experimentally observed protrusion dynamics by reproducing in very good approximation the repetitive protrusion formation measured by Burnette et al. with respect to the velocities of leading edge protrusion and retrograde flow, oscillation amplitudes, periods and shape, as well as the phase relation between protrusion and retrograde flow. Our modeling results agree with the mechanism of actin bundle formation during lamellipodium retraction suggested by

  6. Formation of transient lamellipodia.

    Zimmermann, Juliane; Falcke, Martin


    Cell motility driven by actin polymerization is pivotal to the development and survival of organisms and individual cells. Motile cells plated on flat substrates form membrane protrusions called lamellipodia. The protrusions repeatedly appear and retract in all directions. If a lamellipodium is stabilized and lasts for some time, it can take over the lead and determine the direction of cell motion. Protrusions traveling along the cell perimeter have also been observed. Their initiation is in some situations the effect of the dynamics of the pathway linking plasma membrane receptors to actin filament nucleation, e.g. in chemotaxis. However, lamellipodia are also formed in many cells incessantly during motion with a constant state of the signaling pathways upstream from nucleation promoting factors (NPFs), or spontaneously in resting cells. These observations strongly suggest protrusion formation can also be a consequence of the dynamics downstream from NPFs, with signaling setting the dynamic regime but not initiating the formation of individual protrusions. A quantitative mechanism for this kind of lamellipodium dynamics has not been suggested yet. Here, we present a model exhibiting excitable actin network dynamics. Individual lamellipodia form due to random supercritical filament nucleation events amplified by autocatalytic branching. They last for about 30 seconds to many minutes and are terminated by filament bundling, severing and capping. We show the relevance of the model mechanism for experimentally observed protrusion dynamics by reproducing in very good approximation the repetitive protrusion formation measured by Burnette et al. with respect to the velocities of leading edge protrusion and retrograde flow, oscillation amplitudes, periods and shape, as well as the phase relation between protrusion and retrograde flow. Our modeling results agree with the mechanism of actin bundle formation during lamellipodium retraction suggested by Burnette et al. and

  7. Tea aroma formation

    Chi-Tang Ho; Xin Zheng; Shiming Li


    Besides water, tea is one of the most popular beverages around the world. The chemical ingredients and biological activities of tea have been summarized recently. The current review summarizes tea aroma compounds and their formation in green, black, and oolong tea. The flavor of tea can be divided into two categories: taste (non-volatile compounds) and aroma (volatile compounds). All of these aroma molecules are generated from carotenoids, lipids, glycosides, etc. precursors, and also from Ma...

  8. The Star Formation Camera

    Scowen, Paul A; Beasley, Matthew; Calzetti, Daniela; Desch, Steven; Fullerton, Alex; Gallagher, John; Lisman, Doug; Macenka, Steve; Malhotra, Sangeeta; McCaughrean, Mark; Nikzad, Shouleh; O'Connell, Robert; Oey, Sally; Padgett, Deborah; Rhoads, James; Roberge, Aki; Siegmund, Oswald; Shaklan, Stuart; Smith, Nathan; Stern, Daniel; Tumlinson, Jason; Windhorst, Rogier; Woodruff, Robert


    The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of the astrophysical processes and environments relevant for the births and life cycles of stars and their planetary systems, and to investigate and understand the range of environments, feedback mechanisms, and other factors that most affect the outcome of the star and planet formation process. This program addresses the origins and evolution of stars, galaxies, and cosmic structure and has direct relevance for the formation and survival of planetary systems like our Solar System and planets like Earth. We present the design and performance specifications resulting from the implementation study of the camera, conducted ...

  9. Formation of Lunar Swirls

    Bamford, R A; Cruz, F; Kellett, B J; Fonseca, R A; Silva, L O; Trines, R M G M; Halekas, J S; Kramer, G; Harnett, E; Cairns, R A; Bingham, R


    In this paper we show a plausible mechanism that could lead to the formation of the Dark Lanes in Lunar Swirls, and the electromagnetic shielding of the lunar surface that results in the preservation of the white colour of the lunar regolith. We present the results of a fully self-consistent 2 and 3 dimensional particle-in-cell simulations of mini-magnetospheres that form above the lunar surface and show that they are consistent with the formation of `lunar swirls' such as the archetypal formation Reiner Gamma. The simulations show how the microphysics of the deflection/shielding of plasma operates from a kinetic-scale cavity, and show that this interaction leads to a footprint with sharp features that could be the mechanism behind the generation of `dark lanes'. The physics of mini-magnetospheres is described and shown to be controlled by space-charge fields arising due to the magnetized electrons and unmagnetized ions. A comparison between model and observation is shown for a number of key plasma parameters...

  10. Bouyei word formation

    Attasith Boonsawasd


    Full Text Available The Bouyei language is divided into three vernaculars, the southern vernacular, the central vernacular and the southwestern vernacular. This paper aims to describe the lexicology of the southern vernacular of the Bouyei language focusing on word formation process. Bouyei words are formed by affixing, compounding and reduplicating. First, the affixation consists of prefixing and suffixing. Infixing is not found in this language. Second, the compound is divided into the semantic and syntactic compound. Finally, the reduplication is divided into the simple and complex reduplication. The simple reduplication is normally used to emphasize the meaning of the root or to indicate plurality.

  11. Formation control of AAUSHIP

    Østergaard, Nick; Dam, Jeppe; Larsen, Jesper Abildgaard


    Many maritime mapping tasks are today carried out by large research ships, which are very costly to operate. As a way to overcome this, a number of small surveying vessels have been developed called AAUSHIP. In order to efficiently map the an area with such smaller vessels, it is important that s...... that several vessels are able to corporate on the task at hand. In this paper, the developed formation control strategy for the AAUSHIP series of vessels is presented, along with simulation results, which confirms, that the algorithm works as intended....

  12. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:A citation analysis of computer science literature.Information Processing and Manage-

  13. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:A citation analysis of computer science literature.Information Processing and Management,2001,37:661-675.2 Fernandez.M

  14. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5th Ed.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:A citation analysis of computer science literature.Information Processing and Management,2001,37:661-675.

  15. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:A citation analysis of computer science literature.Information Processing and Management,2001,37:661-675.2 Fernandez,M.,Kadiyska,Y.,&Suciu,D.,et al.SilkRoute:A framework for publishing

  16. Formation control of AAUSHIP

    Østergaard, Nick; Dam, Jeppe; Larsen, Jesper Abildgaard


    Many maritime mapping tasks are today carried out by large research ships, which are very costly to operate. As a way to overcome this, a number of small surveying vessels have been developed called AAUSHIP. In order to efficiently map the an area with such smaller vessels, it is important that s...... that several vessels are able to corporate on the task at hand. In this paper, the developed formation control strategy for the AAUSHIP series of vessels is presented, along with simulation results, which confirms, that the algorithm works as intended....

  17. The formation of life

    Kurucz, R L


    The formation of life is an automatic stage in the consolidation of rocky or "terrestrial" planets. The organic (=carbonaceous) matter, light elements, gases, and water must "float" toward the surface and the heavier metals must sink toward the center. Random processes in the molecular soup that fills microfractures in unmelted crust eventually produce self-replicating microtubules. In an appendix I suggest that some primordial crust remains because there is not enough consolidation energy to melt the whole planet. Energy is lost when iron planetesimals first partially melt and then coalesce to form the molten iron planetary core. Stony planetesimals accrete onto the surface of an already consolidated core.

  18. Paleomagnetic chronology and paleoenvironmental records from drill cores from the Hetao Basin and their implications for the formation of the Hobq Desert and the Yellow River

    Li, Baofeng; Sun, Donghuai; Xu, Weihong; Wang, Fei; Liang, Baiqing; Ma, Zhiwei; Wang, Xin; Li, Zaijun; Chen, Fahu


    Reconstructing the Cenozoic environmental history of Hetao Basin, in the northern part of the Ordos Plateau in North China, is important not only for revealing the evolution of the Yellow River, but also for understanding the formation of the Hobq Desert. Here we present the stratigraphic framework of drill core DR01 with length of 2503.18 m, and the results of magnetostratigraphic and ESR dating and multi-proxy analyses of drill core WEDP05 with length of 274.60 m, from the Hetao Basin. The magnetostratigraphic and ESR results indicate that core WEDP05 spans the last ∼1.68 Ma. Stratigraphic sequence of core DR01 indicates that the Hetao area was uplifted and eroded during the early Cenozoic, before subsiding to form a sedimentary basin. Subsequently, the basin was a fluvio-lacustrine environment during the Pliocene and then experienced alternating desert and fluvio-lacustrine conditions during the Quaternary. Sedimentary facies and multi environmental-proxy analyses of core WEDP05 indicate that the basin was occupied by a fluvio-lacustrine system during the following intervals: ∼1.47 - ∼1.30 Ma, ∼1.17 - ∼1.07 Ma, ∼0.68 - ∼0.60 Ma and from ∼0.47 Ma to the last interglacial; and that a desert environment developed during the lake regression phases of ∼1.30 - ∼1.17 Ma, ∼1.07 - ∼0.68 Ma and ∼0.60 - ∼0.47 Ma. The presence of aeolian sand at the base of core WEDP05 suggests that the origin of the Hobq Desert can be traced back to the early Pleistocene, and resulted from the erosion and transportation of exposed fluvio-lacustrine sediments by near-surface winds associated with the Asian winter monsoon. A large river channel in the Hetao Basin may have existed as early as the Pliocene, which was occupied by the Yellow River when its upper reaches formed by at least ∼1.6 Ma. Subsequently, at least since ∼1.2 Ma, the Yellow River formed its drainage system around the Hetao Basin and controlled the paleoenvironment evolution of the basin.

  19. Star Formation in Irregular Galaxies.

    Hunter, Deidre; Wolff, Sidney


    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  20. Parametrising Star Formation Histories

    Simha, Vimal; Conroy, Charlie; Dave, Romeel; Fardal, Mark; Katz, Neal; Oppenheimer, Benjamin D


    We examine the star formation histories (SFHs) of galaxies in smoothed particle hydrodynamics (SPH) simulations, compare them to parametric models that are commonly used in fitting observed galaxy spectral energy distributions, and examine the efficacy of these parametric models as practical tools for recovering the physical parameters of galaxies. The commonly used tau-model, with SFR ~ exp(-t/tau), provides a poor match to the SFH of our SPH galaxies, with a mismatch between early and late star formation that leads to systematic errors in predicting colours and stellar mass-to-light ratios. A one-parameter lin-exp model, with SFR ~ t*exp(-t/tau), is much more successful on average, but it fails to match the late-time behavior of the bluest, most actively star-forming galaxies and the passive, "red and dead" galaxies. We introduce a 4-parameter model, which transitions from lin-exp to a linear ramp after a transition time, which describes our simulated galaxies very well. We test the ability of these paramet...

  1. Satellite formation. II

    Harris, A. W.


    A satellite formation model is extended to include evolution of planetary ring material and elliptic orbital motion. In this model the formation of the moon begins at a later time in the growth of the earth, and a significant fraction of the lunar material is processed through a circumterrestrial debris cloud where volatiles might have been lost. Thus, the chemical differences between the earth and moon are more plausibly accounted for. Satellites of the outer planets probably formed in large numbers throughout the growth of those planets. Because of rapid inward evolution of the orbits of small satellites, the present satellite systems represent only satellites formed in the last few percent of the growths of their primaries. The rings of Saturn and Uranus are most plausibly explained as the debris of satellites disrupted within the Roche limit. Because such a ring would collapse onto the planet in the course of any significant further accretion by the planet, the rings must have formed very near or even after the conclusion of accretion.

  2. Explosions during galaxy formation

    Hugo Martel


    Full Text Available As an idealized model of the e ects of energy release by supernovae during galaxy formation, we consider an explosion at the center of a halo which forms at the intersection of laments in the plane of a cosmological pancake by gravitational instability during pancake collapse. Such halos resemble the virialized objects found in N{body simulations in a CDM universe and, therefore, serve as a convenient, scale{free test{bed model for galaxy formation. ASPH=P3M simulations reveal that such explosions are anisotropic. The energy and metals are channeled into the low density regions, away from the pancake plane. The pancake remains essentially undisturbed, even if the explosion is strong enough to blow away all the gas lo- cated inside the halo at the onset of the explosion and reheat the IGM surrounding the pancake. Infall quickly replenishes this ejected gas and gradually restores the gas fraction as the halo mass continues to grow. Estimates of the collapse epoch and SN energy{release for galaxies of di erent mass in the CDM model can re- late these results to scale{dependent questions of blow{out and blow{away and their implication for early IGM heating and metal enrichment and the creation of dark{matter{dominated dwarf galaxies.

  3. Formation of water bells

    Ybert, Christophe; Clanet, Christophe; Bocquet, Lyderic; Duez, Cyril


    We study experimentally the situation that consist in a liquid jet impacting normally onto a fixed solid disk. Depending on the experimental conditions, the thin liquid film that spreads onto the solid surface can either pour along the surface, or detach form the disk and form a so-called water bell. The dynamics and the stability of such bells as a function of the hydrodynamic parameters such as the jet and disk diameters or the jet velocity, have already been the object of detailed characterization [1]. This experiment of bell formation appears as the symmetric situation compared to that of a solid body impacting a quiescent liquid. In the latter case, it was recently shown [2] that despite large Re and We numbers, the solid surface characteristics were dramatically influencing the impact scenario. In the present study, we consequently revisit this problem of water bell formation by systematically varying the solid surface characteristics (roughness, surface properties, etc.). It is shown here again that surface parameters strongly influence the domain of bell existence. Our measurements are rationalized by a subtle balance between inertia versus capillary forces and wetting contributions on the liquid film in the ejection region. [1] C. Clanet, J. Fluid Mech., 430, 111-147 (2001) [2] C. Duez et al., Nature Physics, 3, 180-183 (2007)

  4. On Formations with Shemetkov Condition

    Wenbin Guo; Lujin Zhu


    A subgroup-closed formation F is called a formation with Shemetkov condition if every minimal non-F-group is either a group of prime order or a Schmidt group. In this paper, we give a necessary and sufficient condition for formations with Shemetkov condition. From this, some known important results follow.

  5. Designing for informed group formation

    Nicolajsen, Hanne Westh; Juel Jacobsen, Alice; Riis, Marianne


    A new design ―project preparation‖ preparing for the group formation in problem based project work is proposed and investigated. The main problem is to overcome group formation based on existing relations. The hypothesis is that theme development and group formation are somewhat counterproductive...

  6. Synapse formation and remodeling


    Synapses are specialized structures that mediate information flow between neurons and target cells,and thus are the basis for neuronal system to execute various functions,including learning and memory.There are around 1011 neurons in the human brain,with each neuron receiving thousands of synaptic inputs,either excitatory or inhibitory.A synapse is an asymmetric structure that is composed of pre-synaptic axon terminals,synaptic cleft,and postsynaptic compartments.Synapse formation involves a number of cell adhesion molecules,extracellular factors,and intracellular signaling or structural proteins.After the establishment of synaptic connections,synapses undergo structural or functional changes,known as synaptic plasticity which is believed to be regulated by neuronal activity and a variety of secreted factors.This review summarizes recent progress in the field of synapse development,with particular emphasis on the work carried out in China during the past 10 years(1999-2009).

  7. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:A citation analysis of computer science literature.Information Processing and Management,2001,37:661-675.2 Fernandez,M.,Kadiyska,Y.,&Suciu,D.,et al.SilkRoute:A framework for publishing relational data in XML.ACM Transactions on Database Systems,2002,27(4):438-493.

  8. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:A citation analysis of computer science literature.Information Processing and Management,2001,37:661-675.2 Fernandez,M.,Kadiyska,Y.,&Suciu,D.,et al.SilkRoute:A framework for publishing relational data in XML.ACM Transactions on Database Systems,2002,27(4):438-493.

  9. Reference Citation Format


    <正>The format for citations in text and for bibliographic references follows the Publication Manual of the American Psychological Association(5thEd.,2001)and GB/T 7714-2005.The citation of printed word should be ordered in number as it appears in the text of the submitted article.For journal article1 Goodrum,A.A.,McCain,K.W.,&Lawrence,S.,et al.Scholarly publishing in the Internet age:A citation analysis of computer science literature.Information Processing and Management,2001,37:661-675.2 Fernandez,M.,Kadiyska,Y.,&Suciu,D.,et al.SilkRoute:A framework for publishing relational data in XML.ACM Transactions on Database Systems,2002,27(4):438-493.

  10. Myxobacteria Fruiting Body Formation

    Jiang, Yi


    Myxobacteria are social bacteria that swarm and glide on surfaces, and feed cooperatively. When starved, tens of thousands of cells change their movement pattern from outward spreading to inward concentration; they form aggregates that become fruiting bodies, inside which cells differentiate into nonmotile, environmentally resistant spores. Traditionally, cell aggregation has been considered to imply chemotaxis, a long-range cell interaction mediated by diffusing chemicals. However, myxobacteria aggregation is the consequence of direct cell-contact interactions. I will review our recent efforts in modeling the fruiting body formation of Myxobacteria, using lattice gas cellular automata models that are based on local cell-cell contact signaling. These models have reproduced the individual phases in Myxobacteria development such as the rippling, streaming, early aggregation and the final sporulation; the models can be unified to simulate the whole developmental process of Myxobacteria.

  11. Nuclear Pasta Formation

    Schneider, A S; Hughto, J; Berry, D K


    The formation of complex nonuniform phases of nuclear matter, known as nuclear pasta, is studied with molecular dynamics simulations containing 51200 nucleons. A phenomenological nuclear interaction is used that reproduces the saturation binding energy and density of nuclear matter. Systems are prepared at an initial density of 0.10fm$^{-3}$ and then the density is decreased by expanding the simulation volume at different rates to densities of 0.01 fm$^{-3}$ or less. An originally uniform system of nuclear matter is observed to form spherical bubbles ("swiss cheese"), hollow tubes, flat plates ("lasagna"), thin rods ("spaghetti") and, finally, nearly spherical nuclei with decreasing density. We explicitly observe nucleation mechanisms, with decreasing density, for these different pasta phase transitions. Topological quantities known as Minkowski functionals are obtained to characterize the pasta shapes. Different pasta shapes are observed depending on the expansion rate. This indicates non equilibrium effects...

  12. Endogenous formation of dimethylamine.

    Zeisel, S H; DaCosta, K A; Fox, J G


    An understanding of the biosynthesis and metabolism of dimethylamine (DMA) is important because it is a precursor of dimethylnitrosamine (nitroso-DMA). DMA is the major short-chain aliphatic amine in human and rat urine. DMA is formed from trimethylamine (TMA), which, in turn, is a breakdown product of dietary choline. Enzymes within gut bacteria catalyse both of these reactions; it is not known whether mammalian cells can form DMA. To determine the relative importance of dietary choline, bacteria and other mechanisms for the formation of DMA, we measured DMA excretion in the urine of rats fed on a diet devoid of choline, and in urine of rats with no bacterial colonization of the intestines. We also describe an improved gas-chromatographic method for the measurement of methylamines in biological fluids. In control rats there were significant amounts of DMA within several biological fluids [urine, 54.2 +/- 3.0 mumol/kg body wt. per 24 h (556.2 +/- 37.5 nmol/ml); blood, 18.8 +/- 1.9 nmol/ml; gastric juice, 33.5 +/- 10.5 nmol/ml; means +/- S.E.M.]. Animals eating a diet containing no choline excreted as much MMA and DMA as did choline-supplemented rats (25-35 mumol/kg per 24 h), and they excreted slightly less TMA (2 versus 2.5 mumol/kg per 24 h). Rats with no gut bacteria excreted the same amount of DMA in their urine as did the control animals (45-55 mumol/kg per 24 h). They excreted much less MMA (16.3 +/- 1.5 versus 40.3 +/- 2.6 mumol/kg per 24 h; mean +/- S.E.M.; P less than 0.01), TMA (0.7 +/- 0.2 versus 2.5 +/- 0.5 mumol/kg per 24 h; mean +/- S.E.M.; P less than 0.01) and piperidine (2.0 +/- 0.3 versus 6.3 +/- 0.6 mumol/kg per 24 h; mean +/- S.E.M.; P less than 0.01) in their urine. From our studies we conclude that DMA is present in significant amounts within gastric fluid, an environment that is ideal for nitrosamine formation (under acidic conditions, nitroso-DMA is chemically formed by the reaction of nitrite with DMA). Results also indicate that dietary

  13. Group Formation in Economics

    Demange, Gabrielle; Wooders, Myrna


    Broad and diverse ranges of activities are conducted within and by organized groups of individuals, including political, economic and social activities. These activities have recently become a subject of intense interest in economics and game theory. Some of the topics investigated in this collection are models of networks of power and privilege, trade networks, co-authorship networks, buyer-seller networks with differentiated products, and networks of medical innovation and the adaptation of new information. Other topics are social norms on punctuality, clubs and the provision of club goods and public goods, research and development and collusive alliances among corporations, and international alliances and trading agreements. While relatively recent, the literature on game theoretic studies of group formation in economics is already vast. This volume provides an introduction to this important literature on game-theoretic treatments of situations with networks, clubs, and coalitions, including some applications.

  14. Symbol Formation Reconsidered

    Wagoner, Brady


    Werner and Kaplan’s Symbol formation was published 50 years ago but its insights have yet to be adequately explored by psychology and other social sciences. This special issue aims to revisit this seminal work in search of concepts to work on key issues facing us today. This introductory article...... begins with a brief outline and contextualization of the book as well as of the articles that this special issue comprises. The first two articles were written by contributors who were part of the Werner era at Clark University. They explore the key concepts of the organismic and development, and situate...... them vis-à-vis other research at Clark and in American psychology more generally. The second two articles analyse Werner and Kaplan’s notions of ‘distancing’ and ‘physiognomic metaphor’, showing their roots in naturphilosophie and comparing them with contemporary theories. The last four articles apply...

  15. Symbol Formation Reconsidered

    Wagoner, Brady


    them vis-à-vis other research at Clark and in American psychology more generally. The second two articles analyse Werner and Kaplan’s notions of ‘distancing’ and ‘physiognomic metaphor’, showing their roots in naturphilosophie and comparing them with contemporary theories. The last four articles apply......Werner and Kaplan’s Symbol formation was published 50 years ago but its insights have yet to be adequately explored by psychology and other social sciences. This special issue aims to revisit this seminal work in search of concepts to work on key issues facing us today. This introductory article...... begins with a brief outline and contextualization of the book as well as of the articles that this special issue comprises. The first two articles were written by contributors who were part of the Werner era at Clark University. They explore the key concepts of the organismic and development, and situate...

  16. Cosmological Structure Formation

    Primack, Joel R


    LCDM is remarkably successful in predicting the cosmic microwave background and large-scale structure, and LCDM parameters have been determined with only mild tensions between different types of observations. Hydrodynamical simulations starting from cosmological initial conditions are increasingly able to capture the complex interactions between dark matter and baryonic matter in galaxy formation. Simulations with relatively low resolution now succeed in describing the overall galaxy population. For example, the EAGLE simulation in volumes up to 100 cubic Mpc reproduces the observed local galaxy mass function nearly as well as semi-analytic models. It once seemed that galaxies are pretty smooth, that they generally grow in size as they evolve, and that they are a combination of disks and spheroids. But recent HST observations combined with high-resolution hydrodynamic simulations are showing that most star-forming galaxies are very clumpy; that galaxies often undergo compaction which reduces their radius and ...

  17. Formation of Service Ecosystems

    Jonas, Julia M.; Sörhammar, David; Satzger, Gerhard

    Purpose: Researchers in several different academic disciplines (such as marketing, information systems, and organization) have focused on investigating service and business ecosystems (e.g. Lusch and Nambisan, 2015; Gawer and Cusumano, 2014; Kude et al. 2012). We reviewed 69 papers in service...... – i.e. the “birth phase” (Moore, 2009) of a service ecosystem. This paper, therefore, aims to explore how the somewhat “magic” processes of service ecosystem formation that are being taken for granted actually occur. Methodology/Approach: Building on a review of core elements in the definitions...... proposition; a value proposition (e.g., a business opportunity or a business idea) may form the starting point for actors to collaborate and integrate resources in order realize the value proposition. The initiator of a service ecosystem could for example be an actor (Mark Zuckerberg), resources (website...

  18. Frost formation with salt

    Guadarrama-Cetina, J.; Mongruel, A.; González-Viñas, W.; Beysens, D.


    The formation of frost in presence of salt (NaCl) crystal is experimentally investigated on a hydrophobic surface. It presents several remarkable features due to the interplay of salty-water saturation pressure evolution, initially lower than the saturation pressure of ice and water, and the percolating propagation of ice dendrites from defects throughout the supercooled water droplet pattern. In particular, it is remarkable that nucleation of supercooled water and/or ice is prevented around the salty drop in a region of inhibited condensation where the substrate remains dry. As condensation proceeds, salt concentration decreases to eventually become lower than ice's, allowing ice dendrites to hit the salty drop. Salty water then melts ice but eventually freezes as an effect of dilution.

  19. Chinese Affixes and Word Formation

    Fu Ruomei


    Full Text Available Chinese language is one of the typical isolated languages. It lacks morphological variation; part of speech has no morphological signs; the additional component of word formation is less; and the roots never change their forms. The major method of Chinese word formation is the combination of roots according to certain grammatical relations. Although the affix word formation is not part of mainstream Chinese word formation, affix-formation is still an integral part of the Chinese word-formation. Article used literature review, summarized the types and meanings of Chinese affixes. And meanwhile, article analyzed word formation function of Chinese Affixes and quasi-affixes. The Chinese quasi-affixes have stronger capabilities in forming new words, but development direction of Chinese quasi-affixes has to stand the test of time.

  20. Modeling Formation of Globular Clusters: Beacons of Galactic Star Formation

    Gnedin, Oleg Y


    Modern hydrodynamic simulations of galaxy formation are able to predict accurately the rates and locations of the assembly of giant molecular clouds in early galaxies. These clouds could host star clusters with the masses and sizes of real globular clusters. I describe current state-of-the-art simulations aimed at understanding the origin of the cluster mass function and metallicity distribution. Metallicity bimodality of globular cluster systems appears to be a natural outcome of hierarchical formation and gradually declining fraction of cold gas in galaxies. Globular cluster formation was most prominent at redshifts z>3, when massive star clusters may have contributed as much as 20% of all galactic star formation.

  1. Isolating Triggered Star Formation

    Barton, Elizabeth J; Zentner, Andrew R; Bullock, James S; Wechsler, Risa H


    Galaxy pairs provide a potentially powerful means of studying triggered star formation from galaxy interactions. We use a large cosmological N-body simulation coupled with a well-tested semi-analytic substructure model to demonstrate that the majority of galaxies in close pairs reside within cluster or group-size halos and therefore represent a biased population, poorly suited for direct comparison to ``field'' galaxies. Thus, the frequent observation that some types of galaxies in pairs have redder colors than ``field'' galaxies is primarily a selection effect. We select galaxy pairs that are isolated in their dark matter halos with respect to other massive subhalos (N=2 halos) and a control sample of isolated galaxies (N=1 halos) for comparison. We then apply these selection criteria to a volume-limited subset of the 2dF Galaxy Redshift Survey with M_Bj ~ 5 above their average past value, while only 10% of isolated galaxies in the control sample show this level of enhancement. Thus, 14% (20 %) of the galaxi...

  2. Formation of "bound

    Nowak, K.; Kästner, M.; Miltner, A.


    During degradation of organic pollutants in soil, metabolites, microbial biomass, CO2and "bound" residues ("non-extractable" residues in soil organic matter) are formed. Enhanced transformation of these contaminants into "bound" residues has been proposed as an alternative remediation method for polluted soils. However, this kind of residues may pose a potential risk for the environment due to their chemical structure and possible remobilization under different conditions. Therefore particular attention is given actually to "bound" residues. Part of these non-extractable residues may be "biogenic," because microorganisms use the carbon from the pollutant to form their biomass components (fatty acids, amino acids, amino sugars), which subsequently may be incorporated into soil organic matter. Furthermore, the CO2 originating from mineralization of xenobiotics, can be re-assimilated by microorganisms and also incorporated into "biogenic residue". The hazard posed by "bound" residues may be overestimated because they are "biogenic" (contain microbial fatty acids and amino acids). The knowledge about the pathways of "biogenic residue" formation is necessary for a proper assessment of the fate of tested pollutants and their turnover in the soil environment. Moreover, these data are needed to establish the realistic degradation rates of the contaminants in soil. The main objectives of this study are: to quantify the extent of "biogenic residue" (fatty acids, amino acids, amino sugars) formation during the degradation of a model pollutant (2,4-dichlorophenoxyacetic acid = 2,4-D) and during CO2 assimilation by microorganisms and to evaluate which components are mainly incorporated into "bound" residues. To investigate the extent of "biogenic residue" formation in soil during the degradation of 2,4-D, experiments with either 14C-U-ring and 13C6-2,4-D or carboxyl-14C 2,4-D were performed. The incubation experiments were performed according to OECD test guideline 307, in the



    Objective To explore the mechanisms of differentiation and development of pancreatic endocrine cells as well as pancreatic regeneration. Methods Human embryonic pancreatic tissue at 7-14 weeks of gestation was collected. Diabetes mellitus rat model was induced with 65 mg/kg of streptozotocin. Insulin, glucagon, somatostatin, nestin, and cytokeratin 19 (CK19)of pancreatic tissues were observed by immunohistochemistry. Results At 9 weeks of gestation, pancreatic epithelial cells began to co-express insulin, glucagon, somatostatin, and CK19 before migration. Islet cells gradually congregated along with the increase of aging, and at 14 weeks of gestation histological examination showed islet formation. At 12 weeks of gestation, nestin-positive cells could be seen in the pancreatic mesenchyme. During early embryogenesis, islet cells of pancreatic ducts co-expressed insulin, glucagon, and somatostatin. During pancreatic regeneration after damage, nestin expression of islet cells increased. Conclusion In the early stage of embryogenesis, islet cells of primary pancreatic ducts can be differentiated to multipotential endocrine cells before migration. During tissue regeneration, pancreatic stem cells may differentiate and proliferate to form pancreatic islet.

  4. Planet Formation with Migration

    Chambers, J E


    In the core-accretion model, gas-giant planets form solid cores which then accrete gaseous envelopes. Tidal interactions with disk gas cause a core to undergo inward type-I migration in 10^4 to 10^5 years. Cores must form faster than this to survive. Giant planets clear a gap in the disk and undergo inward type-II migration in <10^6 years if observed disk accretion rates apply to the disk as a whole. Type-II migration times exceed typical disk lifetimes if viscous accretion occurs mainly in the surface layers of disks. Low turbulent viscosities near the midplane may allow planetesimals to form by coagulation of dust grains. The radius r of such planetesimals is unknown. If r<0.5 km, the core formation time is shorter than the type-I migration timescale and cores will survive. Migration is substantial in most cases, leading to a wide range of planetary orbits, consistent with the observed variety of extrasolar systems. When r is of order 100m and midplane alpha is of order 3 times 10^-5, giant planets si...

  5. Designing for informed group formation

    Nicolajsen, Hanne Westh; Juel Jacobsen, Alice; Riis, Marianne


    A new design ―project preparation‖ preparing for the group formation in problem based project work is proposed and investigated. The main problem is to overcome group formation based on existing relations. The hypothesis is that theme development and group formation are somewhat counterproductive....... Following research based design methodology an experiment separating the two was initiated.This was to provide for more openness and creativity in contrast to a design in which existing relations seem predominant.......A new design ―project preparation‖ preparing for the group formation in problem based project work is proposed and investigated. The main problem is to overcome group formation based on existing relations. The hypothesis is that theme development and group formation are somewhat counterproductive...

  6. Formation time of hadronic resonances

    Vitev Ivan


    Full Text Available In heavy-ion collisions, formation time of hadrons of high transverse momentum can play a pivotal role in determining the perturbative dynamics of the final-state parton and particle system. We present methods to evaluate the formation times of light hadrons, hadronic resonances, open heavy flavor and quarkonia. Experimental implications of the short formation times of heavy particles are discussed in light of recent RHIC and LHC data.

  7. Spray formation: an inverse cascade

    Ling, Yue; Tryggvason, Gretar; zaleski, Stephane


    We present a study of droplet formation in a gas-liquid mixing layer using direct numerical simulation. It is seen that two mechanisms compete to generate the droplets: fingering at the tip of the waves and hole formation in the thin liquid sheet. The three dimensional liquid structures are much shorter than the longitudinal wavelength of the instability at the first instant of their formation. As time evolves, the structures evolves to larger and larger scales, in a way similar to the inverse cascade of length scales in droplet impact and impact crown formation.

  8. Glass formation - A contemporary view

    Uhlmann, D. R.


    The process of glass formation is discussed from several perspectives. Particular attention is directed to kinetic treatments of glass formation and to the question of how fast a given liquid must be cooled in order to form a glass. Specific consideration is paid to the calculation of critical cooling rates for glass formation, to the effects of nucleating heterogeneities and transients in nucleation on the critical cooling rates, to crystallization on reheating a glass, to the experimental determination of nucleation rates and barriers to crystal nucleation, and to the characteristics of materials which are most conducive to glass formation.

  9. Plasmapause formation at Saturn

    Thomsen, M. F.; Mitchell, D. G.; Jia, X.; Jackman, C. M.; Hospodarsky, G.; Coates, A. J.


    Cassini observations during a rapid, high-latitude, dawnside pass from Saturn's lobe to inner magnetosphere on 25 June 2009 provide strong evidence for the formation of a "plasmapause" at Saturn by Vasyliunas-type nightside reconnection of previously mass-loaded flux tubes. A population of hot, tenuous plasma that lies between the lobe and the dense inner magnetospheric plasma is consistent with a region formed by very recent injection from a reconnection region in the tail, including low density, high temperature, supercorotational flow, a significant O+ content, and the near-simultaneous observation of enhanced Saturn kilometric radiation emissions. The sharp boundary between that region and the cool dense inner magnetospheric plasma thus separates flux tubes that were involved in the reconnection from those that successfully traversed the nightside without mass loss. This event demonstrates that tail reconnection can strip off inner magnetospheric plasma in to at least dipole L = 8.6. Clear evidence of flux tube interchange driven by the sharp boundary is found, both inward moving flux tubes of hotter plasma and, for the first time, the outward moving cool population. The outward moving cool regions have azimuthal sizes less than 1 RS, were probably created within the past 1.2 h, and have outflow speeds greater than about 5 km/s. At the outer edge of the reconnected region, there is also a possible signature of Dungey-type lobe reconnection following the initial Vasyliunas-type reconnection. Observations from this event are entirely consistent with previously described global MHD simulations of tail reconnection, plasmoid departure, and Saturnward injection of reconnected flux.

  10. Formative Assessment Probes: Is It a Rock? Continuous Formative Assessment

    Keeley, Page


    A lesson plan is provided for a formative assessment probe entitled "Is It a Rock?" This probe is designed for teaching elementary school students about rocks through the use of a formative assessment classroom technique (FACT) known as the group Frayer Model. FACT activates students' thinking about a concept and can be used to…

  11. Application of High-resolution Sequence Stratigraphy to the Sand Reservoir Prediction for 8th Member of Lower Shihezi Formation in Sulige Gas Field, Ordos Basin%高分辨率层序地层学在鄂尔多斯盆地苏里格气田苏6井区下石盒子组砂岩储层预测中的应用

    叶泰然; 郑荣才; 文华国



  12. The formation of Pangea

    Stampfli, G. M.; Hochard, C.; Vérard, C.; Wilhem, C.; vonRaumer, J.


    The making of Pangea is the result of large-scale amalgamation of continents and micro-continents, which started at the end of the Neoproterozoic with the formation of Gondwana. As pieces were added to Gondwana on its South-American, Antarctica and Australia side, ribbon-like micro-continents were detached from its African and South-Chinese side: Cadomia in the late Neoproterozoic, Avalonia and Hunia in the Ordovician, Galatia in the Devonian and Cimmeria in the Permian. Cadomia was re-accreted to Gondwana, but the other ribbon-continents were accreted to Baltica, North-China, Laurussia or Laurasia. Finding the origin of these numerous terranes is a major geological challenge. Recently, a global plate tectonic model was developed together with a large geological/geodynamic database, at the Lausanne University, covering the last 600 Ma of the Earth's history. Special attention was given to the placing of Gondwana derived terranes in their original position, using all possible constraints. We propose here a solution for the Variscan terranes, another paper deals with the Altaids. The Galatian super-terrane was detached from Gondwana in the Devonian, during the opening of Paleotethys, and was quickly separated into four sub-terranes that started to by-pass each other. The leading terranes collided at the end of the Devonian with the Hanseatic terrane detached from Laurussia. In the Carboniferous, Gondwana started to impinge onto the amalgamated terranes, creating the Variscan chain and the Pangean super-continent. East of Spain Paleotethys remained opened until the Triassic, subducting northward under Laurasia. Roll-back of the Paleotethyan slab triggered the collapse of most of the European Variscan orogen, which was replaced by series of Permian rifts, some of them becoming oceanized back-arc basins during the Triassic. Major force changes at the Pangean plate limits at the end of the Triassic provoked its break-up, through the opening of the proto

  13. Satellite formation flying relative dynamics, formation design, fuel optimal maneuvers and formation maintenance

    Wang, Danwei; Poh, Eng Kee


    This book systematically describes the concepts and principles for multi-satellite relative motion, passive and near passive formation designs, trajectory planning and control for fuel optimal formation maneuvers, and formation flying maintenance control design. As such, it provides a sound foundation for researchers and engineers in this field to develop further theories and pursue their implementations. Though satellite formation flying is widely considered to be a major advance in space technology, there are few systematic treatments of the topic in the literature. Addressing that gap, the book offers a valuable resource for academics, researchers, postgraduate students and practitioners in the field of satellite science and engineering.

  14. Portable File Format (PFF) specifications

    Dolan, Daniel H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    Created at Sandia National Laboratories, the Portable File Format (PFF) allows binary data transfer across computer platforms. Although this capability is supported by many other formats, PFF files are still in use at Sandia, particularly in pulsed power research. This report provides detailed PFF specifications for accessing data without relying on legacy code.

  15. Identity formation in multiparty negotiations

    Swaab, R; Postmes, T.; Spears, R.


    Based on the recently proposed Interactive Model of Identity Formation, we examine how top-down deductive and bottom-up inductive identity formations influence intentions and behaviour in multiparty negotiations. Results show that a shared identity can be deduced from the social context through reco

  16. Chain formation of metal atoms

    Bahn, Sune Rastad; Jacobsen, Karsten Wedel


    The possibility of formation of single-atomic chains by manipulation of nanocontacts is studied for a selection of metals (Ni, Pd, Pt, Cu, Ag, Au). Molecular dynamics simulations show that the tendency for chain formation is strongest for Au and Pt. Density functional theory calculations indicate...

  17. Potential Maximizers and Network Formation

    Slikker, M.; Dutta, P.K.; van den Nouweland, C.G.A.M.; Tijs, S.H.


    In this paper we study the formation of cooperation structures in superadditive cooperative TU-games.Cooperation structures are represented by hypergraphs.The formation process is modelled as a game in strategic form, where the payoffs are determined according to a weighted (extended) Myerson value.

  18. Sparse Matrix Vector Processing Formats

    Stathis, P.T.


    In this dissertation we have identified vector processing shortcomings related to the efficient storing and processing of sparse matrices. To alleviate existent problems we propose two storage formats denoted as Block Based Compression Storage (BBCS) format and Hierarchical Sparse Matrix (HiSM) stor

  19. Tariffs Formation on oil transportation

    Glyzina, T. S.; Kolbysheva, Yu. V.; Grivtsova, I. S.; Dmitrieva, N. V.


    Oil transportation via trunk pipelines is an important part of the oil industry's activity. The main instrument of tariff regulation is the method of tariffs formation. Three methods of tariffs formation such as the method of economically justified costs (the Cost plus method), the method of economically justified return on investment capital (the RAB method), and the method of tariffs indexation were considered.

  20. Pathogenesis of postoperative adhesion formation

    Hellebrekers, B.W.J.; Kooistra, T.


    Background: Current views on the pathogenesis of adhesion formation are based on the "classical concept of adhesion formation", namely that a reduction in peritoneal fibrinolytic activity following peritoneal trauma is of key importance in adhesion development. Methods: A non-systematic literature

  1. The Principal as Formative Coach

    Nidus, Gabrielle; Sadder, Maya


    Formative coaching, an approach that uses student work as the foundation for mentoring and professional development, can help principals become more effective instructional leaders. In formative coaching, teaches and coaches analyze student work to determine next steps for instruction. This article shows how a principal can use the steps of the…

  2. Cloud formation in giant planets

    Helling, Christiane


    We calculate the formation of dust clouds in atmospheres of giant gas-planets. The chemical structure and the evolution of the grain size distribution in the dust cloud layer is discussed based on a consistent treatment of seed formation, growth/evaporation and gravitational settling. Future developments are shortly addressed.


    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As ...

  4. Bundle Formation in Biomimetic Hydrogels

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J


    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and

  5. Physics of primordial star formation

    Yoshida, Naoki


    The study of primordial star formation has a history of nearly sixty years. It is generally thought that primordial stars are one of the key elements in a broad range of topics in astronomy and cosmology, from Galactic chemical evolution to the formation of super-massive blackholes. We review recent progress in the theory of primordial star formation. The standard theory of cosmic structure formation posits that the present-day rich structure of the Universe developed through gravitational amplification of tiny matter density fluctuations left over from the Big Bang. It has become possible to study primordial star formation rigorously within the framework of the standard cosmological model. We first lay out the key physical processes in a primordial gas. Then, we introduce recent developments in computer simulations. Finally, we discuss prospects for future observations of the first generation of stars.

  6. Formation depths of Fraunhofer lines

    Gurtovenko, E A


    We have summed up our investigations performed in 1970--1993. The main task of this paper is clearly to show processes of formation of spectral lines as well as their distinction by validity and by location. For 503 photospheric lines of various chemical elements in the wavelength range 300--1000 nm we list in Table the average formation depths of the line depression and the line emission for the line centre and on the half-width of the line, the average formation depths of the continuum emission as well as the effective widths of the layer of the line depression formation. Dependence of average depths of line depression formation on excitation potential, equivalent widths, and central line depth are demonstrated by iron lines.

  7. Star Formation in Spiral Arms

    Elmegreen, Bruce G


    The origin and types of spiral arms are reviewed with an emphasis on the connections between these arms and star formation. Flocculent spiral arms are most likely the result of transient instabilities in the gas that promote dense cloud formation, star formation, and generate turbulence. Long irregular spiral arms are usually initiated by gravitational instabilities in the stars, with the gas contributing to and following these instabilities, and star formation in the gas. Global spiral arms triggered by global perturbations, such as a galaxy interaction, can be wavemodes with wave reflection in the inner regions. They might grow and dominate the disk for several rotations before degenerating into higher-order modes by non-linear effects. Interstellar gas flows through these global arms, and through the more transient stellar spiral arms as well, where it can reach a high density and low shear, thereby promoting self-gravitational instabilities. The result is the formation of giant spiral arm cloud complexes,...

  8. Formative assessments as pedagogic tools

    Ashwin Kumar


    Full Text Available This article aims at presenting a state of the art status of formative assessment as a pedagogic tool. To this end, a brief developmental account of different modes of assessment over the last decades will be presented first. Then, formative assessment will be discussed in its constructivist guise. The present literature on assessment suggests that assessment for learning (formative assessment not only represents an assessment tool but it also serves as a pedagogic tool to enhance learning and thinking. It has also gone to lengths to affect the design of classroom tasks and activities. Attempts have been made to delineate the underlying principles of formative assessment which can be used to picture the formation process of learners’ knowledge and development. Subsequently, alternative assessment techniques of which the present article will give an account have been suggested by scholars to operationalize these principles.

  9. Dwarf galaxy formation with H2-regulated star formation

    Kuhlen, M; Madau, P; Smith, B; Wise, J


    We describe cosmological galaxy formation simulations with the adaptive mesh refinement code Enzo that incorporate a star formation prescription regulated by the local abundance of molecular hydrogen. We show that this H2-regulated prescription leads to a suppression of star formation in low mass halos (M_h 4, alleviating some of the dwarf galaxy problems faced by theoretical galaxy formation models. H2 regulation modifies the efficiency of star formation of cold gas directly, rather than indirectly reducing the cold gas content with "supernova feedback". We determine the local H2 abundance in our most refined grid cells (76 proper parsec in size at z=4) by applying the model of Krumholz, McKee, & Tumlinson, which is based on idealized 1D radiative transfer calculations of H2 formation-dissociation balance in ~100 pc atomic--molecular complexes. Our H2-regulated simulations are able to reproduce the empirical (albeit lower z) Kennicutt-Schmidt relation, including the low Sigma_gas cutoff due to the transi...

  10. Free-format RPG IV

    Martin, Jim


    This how-to guide offers a concise and thorough introduction to the increased productivity, better readability, and easier program maintenance that comes with the free-format style of programming in RPG IV. Although free-format information is available in IBM manuals, it is not separated from everything else, thereby requiring hours of tedious research to track down the information needed. This book provides everything one needs to know to write RPG IV in the free-format style, and author Jim Martin not only teaches rules and syntax but also explains how this new style of coding has the pot

  11. AGN feedback in galaxy formation

    Antonuccio-Delogu, Vincenzo


    During the past decade, convincing evidence has been accumulated concerning the effect of active galactic nuclei (AGN) activity on the internal and external environment of their host galaxies. Featuring contributions from well-respected researchers in the field, and bringing together work by specialists in both galaxy formation and AGN, this volume addresses a number of key questions about AGN feedback in the context of galaxy formation. The topics covered include downsizing and star-formation time scales in massive elliptical galaxies, the connection between the epochs of supermassive black h

  12. The experimental modeling of gas percolation mechanisms in a coal-measure tight sandstone reservoir: A case study on the coal-measure tight sandstone gas in the Upper Triassic Xujiahe Formation, Sichuan Basin, China

    Shizhen Tao


    Full Text Available Tight sandstone gas from coal-measure source rock is widespread in China, and it is represented by the Xujiahe Formation of the Sichuan Basin and the Upper Paleozoic of the Ordos Basin. It is affected by planar evaporative hydrocarbon expulsion of coal-measure source rock and the gentle structural background; hydrodynamics and buoyancy play a limited role in the gas migration-accumulation in tight sandstone. Under the conditions of low permeability and speed, non-Darcy flow is quite apparent, it gives rise to gas-water mixed gas zone. In the gas displacing water experiment, the shape of percolation flow curve is mainly influenced by core permeability. The lower the permeability, the higher the starting pressure gradient as well as the more evident the non-Darcy phenomenon will be. In the gas displacing water experiment of tight sandstone, the maximum gas saturation of the core is generally less than 50% (ranging from 30% to 40% and averaging at 38%; it is similar to the actual gas saturation of the gas zone in the subsurface core. The gas saturation and permeability of the core have a logarithm correlation with a correlation coefficient of 0.8915. In the single-phase flow of tight sandstone gas, low-velocity non-Darcy percolation is apparent; the initial flow velocity (Vd exists due to the slippage effect of gas flow. The shape of percolation flow curve of a single-phase gas is primarily controlled by core permeability and confining pressure; the lower the permeability or the higher the confining pressure, the higher the starting pressure (0.02–0.08 MPa/cm, whereas, the higher the quasi-initial flow speed, the longer the nonlinear section and the more obvious the non-Darcy flow will be. The tight sandstone gas seepage mechanism study shows that the lower the reservoir permeability, the higher the starting pressure and the slower the flow velocity will be, this results in the low efficiency of natural gas migration and accumulation as well as

  13. Understanding Galaxy Formation and Evolution

    Avila-Reese, V


    The old dream of integrating into one the study of micro and macrocosmos is now a reality. Cosmology, astrophysics, and particle physics intersect in a scenario (but still not a theory) of cosmic structure formation and evolution called Lambda Cold Dark Matter (LCDM) model. This scenario emerged mainly to explain the origin of galaxies. In these lecture notes, I first present a review of the main galaxy properties, highlighting the questions that any theory of galaxy formation should explain. Then, the cosmological framework and the main aspects of primordial perturbation generation and evolution are pedagogically detached. Next, I focus on the ``dark side'' of galaxy formation, presenting a review on LCDM halo assembling and properties, and on the main candidates for non-baryonic dark matter. It is shown how the nature of elemental particles can influence on the features of galaxies and their systems. Finally, the complex processes of baryon dissipation inside the non-linearly evolving CDM halos, formation o...

  14. The multifaceted planetesimal formation process

    Johansen, Anders; Tanaka, Hidekazu; Ormel, Chris; Bizzarro, Martin; Rickman, Hans


    Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Left-over planetesimals in the form of asteroids, trans-Neptunian objects and comets provide a unique record of the physical conditions in the solar nebula. Debris from planetesimal collisions around other stars signposts that the planetesimal formation process, and hence planet formation, is ubiquitous in the Galaxy. The planetesimal formation stage extends from micrometer-sized dust and ice to bodies which can undergo run-away accretion. The latter ranges in size from 1 km to 1000 km, dependent on the planetesimal eccentricity excited by turbulent gas density fluctuations. Particles face many barriers during this growth, arising mainly from inefficient sticking, fragmentation and radial drift. Two promising growth pathways are mass transfer, where small aggregates transfer u...

  15. Portfolio Optimization under Habit Formation

    Naryshkin, Roman


    The "standard" Merton formulation of optimal investment and consumption involves optimizing the integrated lifetime utility of consumption, suitably discounted, together with the discounted future bequest. In this formulation the utility of consumption at any given time depends only on the amount consumed at that time. However, it is both theoretically and empirically reasonable that an individuals utility of consumption would depend on past consumption history. Economists term this "Habit Formation". We introduce a new formulation of habit formation which allows non-addictive consumption patterns for a wide variety of utility specification. In this paper we construct a simple mathematical description of this habit formation and present numerical solutions. We compare the results with the standard ones and draw insights obtained from the habit formation. The consumption path tends to increase with time and be less sensitive to the market fluctuations, which perfectly reflects the existence of habit persistenc...

  16. First-order formative rules

    Fuhs, Carsten; Kop, C.


    This paper discusses the method of formative rules for first-order term rewriting, which was previously defined for a higher-order setting. Dual to the well-known usable rules, formative rules allow dropping some of the term constraints that need to be solved during a termination proof. Compared to the higher-order definition, the first-order setting allows for significant improvements of the technique.

  17. Problem of professional personality formation

    Pryazhnikova E.Yu.


    Full Text Available The article presents the current approaches to the problem of professional personality formation. It ana-lyzes the impact of professional identity of students on the choice of the specialist field they make. The article highlights certain aspects of the educational environment which promote to formation of compe-tences in students, relating to their choice of professional occupations. The article presents the analysis of students’ internal and external strivings after graduation from the university and their fulfillment.

  18. Star Formation in Various Environments

    Brosch, N; Spector, O; Zitrin, A


    We describe studies of star formation in various galaxies using primarily observations from the Wise Observatory. In addition to surface photometry in the broad band UBVRI, we also use a set of narrow-band H-alpha filters tuned to different redshifts to isolate the emission line. With these observational data, and using models of evolutionary stellar populations, we unravel the star formation histories of the galaxies and connect them to other parameters, such as the galaxy environment.

  19. Overview of Sequence Data Formats.

    Zhang, Hongen


    Next-generation sequencing experiment can generate billions of short reads for each sample and processing of the raw reads will add more information. Various file formats have been introduced/developed in order to store and manipulate this information. This chapter presents an overview of the file formats including FASTQ, FASTA, SAM/BAM, GFF/GTF, BED, and VCF that are commonly used in analysis of next-generation sequencing data.

  20. Introduction to format: the software tools test formatting program

    Agazzi, C.


    Format is the name of the Software Tools formatter. It allows you to format text according to instructions that you place within the text. The text and instructions for each document you wish to create are kept in files. Each instruction, called a request line, makes changes in the way your document is laid out. For example, you can change the margins within your document to visually set off lists of items or topics. You can also bold face or underline words or sentences to highlight them. Throughout this manual are examples of how to use the Format request lines along with illustrations of the effects request lines have on an example letter. The request lines begin with a period in the first column on the screen. Each request line performs a specific function and is placed on the line immediately in front of the test to be formatted. Output lines are automatically filled; that is, their right margins are justified, without regard to the format of the input test lines.

  1. Formative assessment in Swedish mathematics classroom practice

    Andersson, Catarina; Boström, Erika


    International audience; Using formative assessment has woken interest in many countries because of the potential effect on student achievement. To investigate Swedish teachers' use of formative assessment in mathematics, this study used classroom observations and teacher interviews of 38 mathematics teachers. The teachers used formative assessment, but additional formative activities could support teachers to better take advantage of the potential in using formative assessment.

  2. Treating tar sands formations with karsted zones

    Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX)


    Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

  3. Star formation and structure formation in galaxy collisions

    Bournaud, Frederic


    A number of theoretical and simulation results on star and structure formation in galaxy interactions and mergers is reviewed, and recent hydrodynamic simulations are presented. The role of gravity torques and ISM turbulence in galaxy interactions, in addition to the tidal field, is highlighted. Interactions can drive gas inflows towards the central kpc and trigger a central starburst, the intensity and statistical properties of which are discussed. A kinematically decoupled core and a supermassive central black hole can be fueled. Outside of the central kpc, many structures can form inside tidal tails, collisional ring, bridges, including super star clusters and tidal dwarf galaxies. The formation of super star clusters in galaxy mergers can now be directly resolved in hydrodynamic simulations. Their formation mechanisms and long-term evolution are reviewed, and the connection with present-day early-type galaxies is discussed.

  4. An Adaptable Seismic Data Format

    Krischer, Lion; Smith, James; Lei, Wenjie; Lefebvre, Matthieu; Ruan, Youyi; de Andrade, Elliott Sales; Podhorszki, Norbert; Bozdağ, Ebru; Tromp, Jeroen


    We present ASDF, the Adaptable Seismic Data Format, a modern and practical data format for all branches of seismology and beyond. The growing volume of freely available data coupled with ever expanding computational power opens avenues to tackle larger and more complex problems. Current bottlenecks include inefficient resource usage and insufficient data organization. Properly scaling a problem requires the resolution of both these challenges, and existing data formats are no longer up to the task. ASDF stores any number of synthetic, processed or unaltered waveforms in a single file. A key improvement compared to existing formats is the inclusion of comprehensive meta information, such as event or station information, in the same file. Additionally, it is also usable for any non-waveform data, for example, cross-correlations, adjoint sources or receiver functions. Last but not least, full provenance information can be stored alongside each item of data, thereby enhancing reproducibility and accountability. Any data set in our proposed format is self-describing and can be readily exchanged with others, facilitating collaboration. The utilization of the HDF5 container format grants efficient and parallel I/O operations, integrated compression algorithms and check sums to guard against data corruption. To not reinvent the wheel and to build upon past developments, we use existing standards like QuakeML, StationXML, W3C PROV and HDF5 wherever feasible. Usability and tool support are crucial for any new format to gain acceptance. We developed mature C/Fortran and Python based APIs coupling ASDF to the widely used SPECFEM3D_GLOBE and ObsPy toolkits.

  5. The dynamics of latifundia formation.

    Chaves, Luis Fernando


    Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia.

  6. The dynamics of latifundia formation.

    Luis Fernando Chaves

    Full Text Available Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia.

  7. Star formation in Galactic flows

    Smilgys, Romas; Bonnell, Ian A.


    We investigate the triggering of star formation in clouds that form in Galactic scale flows as the interstellar medium passes through spiral shocks. We use the Lagrangian nature of smoothed particle hydrodynamics simulations to trace how the star-forming gas is gathered into self-gravitating cores that collapse to form stars. Large-scale flows that arise due to Galactic dynamics create shocks of the order of 30 km s-1 that compress the gas and form dense clouds (n > several × 102 cm-3) in which self-gravity becomes relevant. These large-scale flows are necessary for creating the dense physical conditions for gravitational collapse and star formation. Local gravitational collapse requires densities in excess of n > 103 cm-3 which occur on size scales of ≈1 pc for low-mass star-forming regions (M 103 M⊙). Star formation in the 250 pc region lasts throughout the 5 Myr time-scale of the simulation with a star formation rate of ≈10-1 M⊙ yr-1 kpc-2. In the absence of feedback, the efficiency of the star formation per free-fall time varies from our assumed 100 per cent at our sink accretion radius to values of <10-3 at low densities.

  8. VLBI Data Interchange Format (VDIF)

    Whitney, Alan; Kettenis, Mark; Phillips, Chris; Sekido, Mamoru


    One important outcome of the 7th International e-VLBI Workshop in Shanghai in June 2008 was the creation of a task force to study and recommend a universal VLBI data format that is suitable for both on-the-wire e-VLBI data transfer, as well as direct disk storage. This task force, called the VLBI Data Interchange Format (VDIF) Task Force, is the first part of a two-part effort, the second of which will address standardization of e-VLBI data-transmission-protocols. The formation of the VDIF Task Force was prompted particularly by increased e-VLBI activity and the difficulties encountered when data arrive at a correlator in different formats from various instruments in various parts of the world. The task force created a streaming packetized data format that may be used for real-time and non-realtime e-VLBI, as well as direct disk storage. The data may contain multiple channels of time-sampled data with an arbitrary number of channels, arbitrary #bits/sample up to 32, and real or complex data; data rates in excess of 100 Gbps are supported. Each data packet is completely self-identifying via a short header, and data may be decoded without reference to any external information. The VDIF task force has completed its work, and the VDIF standard was ratified at the 2009 e-VLBI workshop in Madrid.

  9. Formation of porous gas hydrates

    Salamatin, Andrey N


    Gas hydrates grown at gas-ice interfaces are examined by electron microscopy and found to have a submicron porous texture. Permeability of the intervening hydrate layers provides the connection between the two counterparts (gas and water molecules) of the clathration reaction and makes further hydrate formation possible. The study is focused on phenomenological description of principal stages and rate-limiting processes that control the kinetics of the porous gas hydrate crystal growth from ice powders. Although the detailed physical mechanisms involved in the porous hydrate formation still are not fully understood, the initial stage of hydrate film spreading over the ice surface should be distinguished from the subsequent stage which is presumably limited by the clathration reaction at the ice-hydrate interface and develops after the ice grain coating is finished. The model reveals a time dependence of the reaction degree essentially different from that when the rate-limiting step of the hydrate formation at...

  10. Structure formation in active networks

    Köhler, Simone; Bausch, Andreas R


    Structure formation and constant reorganization of the actin cytoskeleton are key requirements for the function of living cells. Here we show that a minimal reconstituted system consisting of actin filaments, crosslinking molecules and molecular-motor filaments exhibits a generic mechanism of structure formation, characterized by a broad distribution of cluster sizes. We demonstrate that the growth of the structures depends on the intricate balance between crosslinker-induced stabilization and simultaneous destabilization by molecular motors, a mechanism analogous to nucleation and growth in passive systems. We also show that the intricate interplay between force generation, coarsening and connectivity is responsible for the highly dynamic process of structure formation in this heterogeneous active gel, and that these competing mechanisms result in anomalous transport, reminiscent of intracellular dynamics.

  11. Exoplanets Detection, Formation, Properties, Habitability

    Mason, John W


    This edited, multi-author volume will be an invaluable introduction and reference to all key aspects in the field of exoplanet research. The reviews cover: Detection methods and properties of known exoplanets, Detection of extrasolar planets by gravitational microlensing. The formation and evolution of terrestrial planets in protoplanetary and debris disks. The brown dwarf-exoplanet connection. Formation, migration mechanisms and properties of hot Jupiters. Dynamics of multiple exoplanet systems. Doppler exoplanet surveys. Searching for exoplanets in the stellar graveyard. Formation and habitability of extra solar planets in multiple star systems. Exoplanet habitats and the possibilities for life. Moons of exoplanets: habitats for life. Contributing authors: •Rory Barnes •David P. Bennett •Jian Ge •Nader Haghighipour •Patrick Irwin •Hugh Jones •Victoria Meadows •Stanimir Metchev •I. Neill Reid •George Rieke •Caleb Scharf •Steinn Sigurdsson

  12. Black holes and galaxy formation

    Propst, Raphael J


    Galaxies are the basic unit of cosmology. The study of galaxy formation is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning. The physics of galaxy formation is complicated because it deals with the dynamics of stars, thermodynamics of gas and energy production of stars. A black hole is a massive object whose gravitational field is so intense that it prevents any form of matter or radiation to escape. It is hypothesized that the most massive galaxies in the universe- "elliptical galaxies"- grow simultaneously with the supermassive black holes at their centers, giving us much stronger evidence that black holes control galaxy formation. This book reviews new evidence in the field.

  13. Compulsory formation of solvento complexes

    Kukushkin, Yu.N.; Kukushkin, V.Yu.


    The essence of the method of the compulsory formation of solvated complexes which are labile in substitution reactions has been described in this review. It is based on three techniques for eliminating ligands from the inner sphere of the original compounds: 1) binding of the ligands in sparingly soluble productions or their conversion into highly volatile compounds; 2) binding of the ligands in stronger compounds than the original products; 3) chemical conversion of coordinated ligands, which result in a loss of donor capacity by the reaction products and the departure of these products from the inner sphere of the complex compounds. If the solvent in which the reaction is carried out has a sufficient donor capability, the coordination capacity of the central ion is saturated by means of solvent molecules with the formation of a solvento complex. The method has been illustrated by a large number of concrete examples of reactions which result in the formation of compounds with an assigned composition.

  14. Bundle Formation in Biomimetic Hydrogels.

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J


    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks.

  15. Dense Cloud Formation and Star Formation in a Barred Galaxy

    Nimori, M; Sorai, K; Watanabe, Y; Hirota, A; Namekata, D


    We investigate the properties of massive, dense clouds formed in a barred galaxy and their possible relation to star formation, performing a two-dimensional hydrodynamical simulation with the gravitational potential obtained from the 2Mass data from the barred spiral galaxy, M83. Since the environment for cloud formation and evolution in the bar region is expected to be different from that in the spiral arm region, barred galaxies are a good target to study the environmental effects on cloud formation and the subsequent star formation. Our simulation uses for an initial 80 Myr an isothermal flow of non-self gravitating gas in the barred potential, then including radiative cooling, heating and self-gravitation of the gas for the next 40 Myr, during which dense clumps are formed. We identify many cold, dense gas clumps for which the mass is more than $10^4M_{\\odot}$ (a value corresponding to the molecular clouds) and study the physical properties of these clumps. The relation of the velocity dispersion of the i...

  16. Star formation and gas supply

    Catinella, B.


    A detailed knowledge of how gas cycles in and around galaxies, and how it depends on galaxy properties such as stellar mass and star formation rate, is crucial to understand galaxy formation and evolution. We take advantage of the most sensitive surveys of cold gas in massive galaxies, GASS and COLD GASS, as well as of the state-of-the-art HI blind survey ALFALFA to investigate how molecular and atomic hydrogen reservoirs vary along and across the main sequence of star-forming galaxies.

  17. Strategy Formation in Eastern Jutland

    Olesen, Kristian


      In Eastern Jutland a strategy formation process has been initiated with the aim of developing a strategic spatial plan for the city region.  An organisation has been set up to deal with the first phase of the process, which is to carry out three functional analyses and prepare a common vision...... on which level a serious strategy formation process can take place.  There is a danger that a common strategic spatial plan is more an expression of the lowest common denominator and the municipalities request for infrastructure investments rather than being a spatial strategy with transformative power. ...

  18. Optimal Reconfiguration of Tetrahedral Formations

    Huntington, Geoffrey; Rao, Anil V.; Hughes, Steven P.


    The problem of minimum-fuel formation reconfiguration for the Magnetospheric Multi-Scale (MMS) mission is studied. This reconfiguration trajectory optimization problem can be posed as a nonlinear optimal control problem. In this research, this optimal control problem is solved using a spectral collocation method called the Gauss pseudospectral method. The objective of this research is to provide highly accurate minimum-fuel solutions to the MMS formation reconfiguration problem and to gain insight into the underlying structure of fuel-optimal trajectories.

  19. Magnetohydrodynamic mechanism for pedestal formation.

    Guazzotto, L; Betti, R


    Time-dependent two-dimensional magnetohydrodynamic simulations are carried out for tokamak plasmas with edge poloidal flow. Differently from conventional equilibrium theory, a density pedestal all around the edge is obtained when the poloidal velocity exceeds the poloidal sound speed. The outboard pedestal is induced by the transonic discontinuity, the inboard one by mass redistribution. The density pedestal follows the formation of a highly sheared flow at the transonic surface. These results may be relevant to the L-H transition and pedestal formation in high performance tokamak plasmas.

  20. Formation Criterion for Synthetic Jets


    formation data for the axisymmetric case were published over 50 years ago by Ingard and Labate.10 More recent studies33,34 suggest that L0/d > 1 for...with the axisymmetric data from Ingard and Labate10 and Smith et al.33 are compared in Fig. 7. It is found that the available data are consis- tent with...the jet formation criterion with an empirically determined constant K equal to approximately 0.16. The deviation of Ingard and Labate’s data at their

  1. Pattern formations and oscillatory phenomena

    Kinoshita, Shuichi


    Patterns and their formations appear throughout nature, and are studied to analyze different problems in science and make predictions across a wide range of disciplines including biology, physics, mathematics, chemistry, material science, and nanoscience. With the emergence of nanoscience and the ability for researchers and scientists to study living systems at the biological level, pattern formation research has become even more essential. This book is an accessible first of its kind guide for scientists, researchers, engineers, and students who require a general introduction to thi

  2. Terrestrial Planet Formation: Constraining the Formation of Mercury

    Lykawka, Patryk Sofia; Ito, Takashi


    How the four terrestrial planets of the solar system formed is one of the most fundamental questions in the planetary sciences. Particularly, the formation of Mercury remains poorly understood. We investigated terrestrial planet formation by performing 110 high-resolution N-body simulation runs using more than 100 embryos and 6000 disk planetesimals representing a primordial protoplanetary disk. To investigate the formation of Mercury, these simulations considered an inner region of the disk at 0.2–0.5 au (the Mercury region) and disks with and without mass enhancements beyond the ice line location, a IL, in the disk, where a IL = 1.5, 2.25, and 3.0 au were tested. Although Venus and Earth analogs (considering both orbits and masses) successfully formed in the majority of the runs, Mercury analogs were obtained in only nine runs. Mars analogs were also similarly scarce. Our Mercury analogs concentrated at orbits with a ∼ 0.27–0.34 au, relatively small eccentricities/inclinations, and median mass m ∼ 0.2 {M}\\oplus . In addition, we found that our Mercury analogs acquired most of their final masses from embryos/planetesimals initially located between 0.2 and ∼1–1.5 au within 10 Myr, while the remaining mass came from a wider region up to ∼3 au at later times. Although the ice line was negligible in the formation of planets located in the Mercury region, it enriched all terrestrial planets with water. Indeed, Mercury analogs showed a wide range of water mass fractions at the end of terrestrial planet formation.

  3. Exciton Formation in Disordered Semiconductors

    Klochikhin, A.; Reznitsky, A.; Permogorov, S.


    Stationary luminescence spectra of disordered solid solutions can be accounted by the model of localized excitons. Detailed analysis of the long time decay kinetics of luminescence shows that exciton formation in these systems is in great extent due to the bimolecular reaction of separated carrie...

  4. Inside-Out Planet Formation

    Chatterjee, Sourav


    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theory. Formation in situ from disks with radial mass surface density profiles similar to the minimum mass solar nebula (MMSN) but boosted in normalization by factors ~10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm--m size) "pebbles", drifting inwards via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magneto-rotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ~1--10 M_\\Earth planet directly or induces gradual planet formation via core accretion. The planet continues to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow....

  5. The EPRDATA Format: A Dialogue

    Hughes, Henry Grady III [Los Alamos National Laboratory


    Recently the Los Alamos Nuclear Data Team has communicated certain issues of concern in relation to the new electron/photon/relaxation ACE data format as released in the eprdata12 library. In this document those issues are parsed, analyzed, and answered.

  6. Stereotype Formation : Biased by Association

    Le Pelley, Mike E.; Reimers, Stian J.; Calvini, Guglielmo; Spears, Russell; Beesley, Tom; Murphy, Robin A.


    We propose that biases in attitude and stereotype formation might arise as a result of learned differences ill the extent its which social groups have previously been predictive elf behavioral or physical properties Experiments 1 and 2 demonstrate that differences in the experienced predictiveness o

  7. Exciton Formation in Disordered Semiconductors

    Klochikhin, A.; Reznitsky, A.; Permogorov, S.


    Stationary luminescence spectra of disordered solid solutions can be accounted by the model of localized excitons. Detailed analysis of the long time decay kinetics of luminescence shows that exciton formation in these systems is in great extent due to the bimolecular reaction of separated carrier...

  8. Formative Assessment in Dance Education

    Andrade, Heidi; Lui, Angela; Palma, Maria; Hefferen, Joanna


    Feedback is crucial to students' growth as dancers. When used within the framework of formative assessment, or assessment for learning, feedback results in actionable next steps that dancers can use to improve their performances. This article showcases the work of two dance specialists, one elementary and one middle school teacher, who have…

  9. Electrochemical analysis of microdroplet formation

    Fukuyama, M.; Yoshida, Y.; Eijkel, J.C.T.; Berg, van den A.; Hibara, A.; Fujii, T.; Hibara, A.; Takeuchi, S.; Fukuba, T.


    This paper reports an electrochemical measurement system with a high-speed camera for observation of molecular transport phenomena at a water-oil (W/O) interface during microfluidic droplet formation. For demonstration of the system, currents corresponding to the transport of electrolyte ions to for

  10. Adventitious root formation in Arabidopsis

    Massoumi, Mehdi


    Adventitious root (AR) formation is indispensable in vegetative propagation and is widely used. A better understanding of the underlying mechanisms is needed to improve rooting treatments. We first established a system to study rooting in Arabidopsis, the model organism in plant biology but only occ

  11. Formative Assessment in Dance Education

    Andrade, Heidi; Lui, Angela; Palma, Maria; Hefferen, Joanna


    Feedback is crucial to students' growth as dancers. When used within the framework of formative assessment, or assessment for learning, feedback results in actionable next steps that dancers can use to improve their performances. This article showcases the work of two dance specialists, one elementary and one middle school teacher, who have…

  12. Mediating Among Diverse Data Formats.


    different text editors often want to share documents, Microsoft Word programs permit users to load documents not only in Word’s own formats, but also in...HTML 47 0 DVI to PDF 42 0 Word to Postscript 39 2 error retrieving document Postscript to webbed images 25 1 ghostscript did not return I£ TEXto

  13. The Road to Galaxy Formation

    Keel, William C


    The formation of galaxies is one of the greatest puzzles in astronomy, the solution is shrouded in the depths of space and time, but has profound implications for the universe we observe today. The book discusses the beginnings of the process from cosmological observations and calculations, considers the broad features of galaxies that we need to explain and what we know of their later history. The author compares the competing theories for galaxy formation and considers the progress expected from new generations of powerful telescopes both on earth and in space. In this second edition the author has retained the observationally-based approach of the first edition, a feature which was particularly well-reviewed: Writing in Nature, Carlton Baugh noted in February 2003 that “It is refreshing, in a market dominated by theorists, to come across a book on galaxy formation written from an observational perspective. The Road to Galaxy Formation should prove to be a handy primer on observations for graduate student...

  14. Formation of Rationally Heterogeneous Expectations

    Pfajfar, D.


    Abstract: This paper models expectation formation by taking into account that agents produce heterogeneous expectations due to model uncertainty, informational frictions and different capacities for processing information. We show that there are two general classes of steady states within this frame

  15. Genetic analysis of symbiosome formation

    Ovchinnikova, E.


    Endosymbiotic interactions form a fundament of life as we know it and are characterized by the formation of new specialized membrane compartments, in which the microbes are hosted inside living plant cells. A striking example is the symbiosis between legumes and nitrogen-fixing Rhizobium bacteria

  16. The Formation of Galactic Bulges

    Peletier, R.; Balcells, M.; Falcon-Barroso, J.; Graham, A.


    We summarise some recent results about nearby galactic bulges that are relevant to their formation. We highlight a number of significant advances in our understanding of the surface brightness profiles, stellar populations, and especially the very centers of spiral galaxies. We also view our own Mil

  17. Genetic analysis of symbiosome formation

    Ovchinnikova, E.


    Endosymbiotic interactions form a fundament of life as we know it and are characterized by the formation of new specialized membrane compartments, in which the microbes are hosted inside living plant cells. A striking example is the symbiosis between legumes and nitrogen-fixing Rhizobium bacteria (r

  18. Formative Evaluations in Online Classes

    Jennifer Peterson


    Full Text Available Online courses are continuing to become an important component of higher education course offerings. As the number of such courses increases, the need for quality course evaluations and course improvements is also increasing. However, there is not general agreement on the best ways to evaluate and use evaluation data to improve online courses. While summative student evaluations are commonly used, these may not be the most effective for online course evaluation and quality improvement. Formative evaluation is one method of providing course evaluation and feedback to the instructor during the course while course improvements can be made to benefit the students currently in the course as well as future students. This method of evaluation not only provides for an effective course evaluation but also continuous improvement in the course. This case study reviews formative evaluations done in two online courses in a Health Information Management program. These formative evaluations were found to be quite effective for the identification and development of needed course improvement throughout the semester as well as for use as input into overall course evaluations. These evaluations demonstrate the value of formative evaluations and provide a methodology for implementing such evaluations into an online course.

  19. The multifaceted planetesimal formation process

    Johansen, Anders; Blum, Jürgen; Tanaka, Hidekazu


    Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Left-over planetesimals in the form of asteroids, trans-Nept...

  20. Galaxy Formation and SN Feedback

    Tissera, P B; White, S D M; Springel, V


    We present a Supernova (SN) feedback model that succeeds at describing the chemical and energetic effects of SN explosions in galaxy formation simulations. This new SN model has been coupled to GADGET-2 and works within a new multiphase scheme which allows the description of a co-spatial mixture of cold and hot interstellar medium phases. No ad hoc scale-dependent parameters are associated to these SN and multiphase models making them particularly suited to studies of galaxy formation in a cosmological framework. Our SN model succeeds not only in setting a self-regulated star formation activity in galaxies but in triggering collimated chemical-enriched galactic winds. The effects of winds vary with the virial mass of the systems so that the smaller the galaxy, the larger the fraction of swept away gas and the stronger the decrease in its star formation activity. The fact that the fraction of ejected metals exceeds 60 per cent regardless of mass, suggests that SN feedback can be the responsible mechanism of th...

  1. Earth and Terrestrial Planet Formation

    Jacobson, Seth A


    The growth and composition of Earth is a direct consequence of planet formation throughout the Solar System. We discuss the known history of the Solar System, the proposed stages of growth and how the early stages of planet formation may be dominated by pebble growth processes. Pebbles are small bodies whose strong interactions with the nebula gas lead to remarkable new accretion mechanisms for the formation of planetesimals and the growth of planetary embryos. Many of the popular models for the later stages of planet formation are presented. The classical models with the giant planets on fixed orbits are not consistent with the known history of the Solar System, fail to create a high Earth/Mars mass ratio, and, in many cases, are also internally inconsistent. The successful Grand Tack model creates a small Mars, a wet Earth, a realistic asteroid belt and the mass-orbit structure of the terrestrial planets. In the Grand Tack scenario, growth curves for Earth most closely match a Weibull model. The feeding zon...

  2. Control over Administrative Contract Formation

    Frane Staničić


    Full Text Available Administrative contracts in Croatian legislation represent a novelty introduced into the General Administration Procedure Act in 2010. This is a novelty which has not proved to be successful in practice. Control over administrative contract formation is inevitable and is very significant for a number of reasons. Firstly, public legal bodies which form them do so by exercising their own public powers which are without doubt subject to legality control; secondly, in forming administrative contracts, public funds are used which must be controlled; thirdly, forming administrative contracts often touches on using public goods. Due to the restrictive interpretation of administrative contracts in Croatian legislation, this institute is indisputably only regulated in the General Taxation Act. However, for more than two decades contracts which satisfy all presumptions have existed in our law in order to be considered as administrative contracts. It is for this reason that control over contracts will be dealt with for contracts considered by the author to be administrative contracts. These are contracts on concessions and contracts on public procurement. How inadequate today’s regulation of control of administrative contract formation is will be demonstrated, particularly regarding contracts on concession and public procurement. Legislative changes will be proposed which should result in a more quality system of control over administrative contract formation. How control over administrative contract formation cannot be considered as separate from control over administrative contract execution will also be shown.

  3. Wintertime Haze Formation in Beijing

    Levy Zamora, M. E.


    Recent severe haze events in China have attracted significant public attention due to the severely reduced visibility and unprecedentedly high pollutant concentrations. Particular attention has been given to the high concentrations of particulate matter with a diameter less than 2.5 microns (PM2.5), which can exceed several hundred micrograms per cubic meter over several days. During January and February of 2015, a suite of aerosol instruments was deployed in Beijing to directly measure a comprehensive set of aerosol properties, including the particle size distribution, effective density, and chemical composition. In this presentation, we will discuss the particulate matter formation mechanisms, the evolution of aerosol properties throughout the event, and how the winter formation mechanisms compare with the warmer seasons. We show that the periodic cycles of severe haze episodes in Beijing are largely driven by meteorological conditions. During haze events, stagnation typically develops as a result of a low planetary boundary layer and weak southerly wind from polluted industrial source regions. Stronger northerly winds were frequently observed during the clean period, which carry unpolluted air masses from the less populated northern mountainous areas. Nucleation consistently occurs on clean days, producing a high number concentration of nano particles. The particle mass concentration exceeding several hundred micrograms per cubic meter is attributed to the continuous size growth from the nucleation-mode particles (diameter less than 10 nm) over multiple days to produce a high concentration of larger particles (diameter greater than 100 nm). The particle chemical composition in Beijing is similar to those commonly measured in other urban centers, which is indicative of chemical constituents dominated by secondary aerosol formation. Our results reveal that the severe haze formation in Beijing during the wintertime is similar to the mechanism of haze formation

  4. H$_2$-based star formation laws in galaxy formation models

    Xie, Lizhi; Hirschmann, Michaela; Fontanot, Fabio; Zoldan, Anna


    We update our recently published model for GAlaxy Evolution and Assembly (GAEA), to include a self-consistent treatment of the partition of cold gas in atomic and molecular hydrogen. Our model provides significant improvements with respect to previous ones used for similar studies. In particular, GAEA (i) includes a sophisticated chemical enrichment scheme accounting for non-instantaneous recycling of gas, metals, and energy; (ii) reproduces the measured evolution of the galaxy stellar mass function; (iii) reproduces the observed correlation between galaxy stellar mass and gas metallicity at different redshifts. These are important prerequisites for models considering a metallicity dependent efficiency of molecular gas formation. We also update our model for disk sizes and show that model predictions are in nice agreement with observational estimates for the gas, stellar and star forming disks at different cosmic epochs. We analyse the influence of different star formation laws including empirical relations b...

  5. Standard Formats for Atomic Data: the APED

    Smith, R K; Brickhouse, N S; Liedahl, D A; Raymond, J C


    Standardized formats for atomic data used in calculating emission from a collisionally-ionized plasma are described. The formats use the astronomical-standard FITS format, and are extendible to other purposes, such as photoionization data. The formats emphasize storing references to the original data source and keeping the data in as-received form, to aid in checking against the original literature.

  6. Treating tar sands formations with dolomite

    Vinegar, Harold J.; Karanikas, John Michael


    Methods for treating a tar sands formation are described herein. The tar sands formation may include dolomite and hydrocarbons. Methods may include providing heat at less than the decomposition temperature of dolomite from one or more heaters to at least a portion of the formation. At least some of the hydrocarbon fluids are mobilized in the formation. At least some of the hydrocarbon fluids may be produced from the formation.

  7. Formation of quasiparallel Alfven solitons

    Hamilton, R. L.; Kennel, C. F.; Mjolhus, E.


    The formation of quasi-parallel Alfven solitons is investigated through the inverse scattering transformation (IST) for the derivative nonlinear Schroedinger (DNLS) equation. The DNLS has a rich complement of soliton solutions consisting of a two-parameter soliton family and a one-parameter bright/dark soliton family. In this paper, the physical roles and origins of these soliton families are inferred through an analytic study of the scattering data generated by the IST for a set of initial profiles. The DNLS equation has as limiting forms the nonlinear Schroedinger (NLS), Korteweg-de-Vries (KdV) and modified Korteweg-de-Vries (MKdV) equations. Each of these limits is briefly reviewed in the physical context of quasi-parallel Alfven waves. The existence of these limiting forms serves as a natural framework for discussing the formation of Alfven solitons.

  8. Molecule Formation on Interstellar Grains

    Vidali, G.


    The first experiments that were expressively designed to be applicable to hydrogen formation reactions in the ISM measured the efficiency of formation of molecular hydrogen on a polycrystalline olivine (Pirronello et al. (1997a)). It soon turned out that more was needed, and research began on the mechanism of reaction, on the in uence of the surface morphology, and on the excitation of the just- ormed molecule. In this review, I summarize what we learned from these and other experiments, and where more work is needed: in the elementary steps of reaction, in the bridging of the laboratory-ISM gap (large ux/large surface - small ux/small grain) using simulations, and in using realistic samples of dust grains. Understanding what experiments can and cannot deliver will help in designing and targeting observations, and vice-versa.

  9. Galaxy formation through hierarchical clustering

    White, Simon D. M.; Frenk, Carlos S.


    Analytic methods for studying the formation of galaxies by gas condensation within massive dark halos are presented. The present scheme applies to cosmogonies where structure grows through hierarchical clustering of a mixture of gas and dissipationless dark matter. The simplest models consistent with the current understanding of N-body work on dissipationless clustering, and that of numerical and analytic work on gas evolution and cooling are adopted. Standard models for the evolution of the stellar population are also employed, and new models for the way star formation heats and enriches the surrounding gas are constructed. Detailed results are presented for a cold dark matter universe with Omega = 1 and H(0) = 50 km/s/Mpc, but the present methods are applicable to other models. The present luminosity functions contain significantly more faint galaxies than are observed.

  10. Coevolutionary modeling in network formation

    Al-Shyoukh, Ibrahim


    Network coevolution, the process of network topology evolution in feedback with dynamical processes over the network nodes, is a common feature of many engineered and natural networks. In such settings, the change in network topology occurs at a comparable time scale to nodal dynamics. Coevolutionary modeling offers the possibility to better understand how and why network structures emerge. For example, social networks can exhibit a variety of structures, ranging from almost uniform to scale-free degree distributions. While current models of network formation can reproduce these structures, coevolutionary modeling can offer a better understanding of the underlying dynamics. This paper presents an overview of recent work on coevolutionary models of network formation, with an emphasis on the following three settings: (i) dynamic flow of benefits and costs, (ii) transient link establishment costs, and (iii) latent preferential attachment.

  11. Shock Formation in Lovelock Theories

    Reall, Harvey S; Way, Benson


    We argue that Lovelock theories of gravity suffer from shock formation, unlike General Relativity. We consider the propagation of (i) a discontinuity in curvature, and (ii) weak, high frequency, gravitational waves. Such disturbances propagate along characteristic hypersurfaces of a "background" spacetime and their amplitude is governed by a transport equation. In GR the transport equation is linear. In Lovelock theories, it is nonlinear and its solutions can blow up, corresponding to the formation of a shock. We show that this effect is absent in some simple cases e.g. a flat background spacetime, and demonstrate its presence for a plane wave background. We comment on weak cosmic censorship, the evolution of shocks, and the nonlinear stability of Minkowski spacetime, in Lovelock theories.

  12. Controlled Irradiative Formation of Penitentes

    Bergeron, V; Betterton, M D


    Spike-shaped structures are produced by light-driven ablation in very different contexts. Penitentes 1-4 m high are common on Andean glaciers, where their formation changes glacier dynamics and hydrology. Laser ablation can produce cones 10-100 microns high with a variety of proposed applications in materials science. We report the first laboratory generation of centimeter-scale snow and ice penitentes. Systematically varying conditions allows identification of the essential parameters controlling the formation of ablation structures. We demonstrate that penitente initiation and coarsening requires cold temperatures, so that ablation leads to sublimation rather than melting. Once penitentes have formed, further growth of height can occur by melting. The penitentes intially appear as small structures (3 mm high) and grow by coarsening to 1-5 cm high. Our results are an important step towards understanding and controlling ablation morphologies.

  13. Photophoresis boosts giant planet formation

    Teiser, Jens


    In the core accretion model of giant planet formation, a solid protoplanetary core begins to accrete gas directly from the nebula when its mass reaches about 5 earth masses. The protoplanet has at most a few million years to reach runaway gas accretion, as young stars lose their gas disks after 10 million years at the latest. Yet gas accretion also brings small dust grains entrained in the gas into the planetary atmosphere. Dust accretion creates an optically thick protoplanetary atmosphere that cannot efficiently radiate away the kinetic energy deposited by incoming planetesimals. A dust-rich atmosphere severely slows down atmospheric cooling, contraction, and inflow of new gas, in contradiction to the observed timescales of planet formation. Here we show that photophoresis is a strong mechanism for pushing dust out of the planetary atmosphere due to the momentum exchange between gas and dust grains. The thermal radiation from the heated inner atmosphere and core is sufficient to levitate dust grains and to ...

  14. Rapid gas hydrate formation process

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.


    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  15. Singularities formation, structure, and propagation

    Eggers, J


    Many key phenomena in physics and engineering are described as singularities in the solutions to the differential equations describing them. Examples covered thoroughly in this book include the formation of drops and bubbles, the propagation of a crack and the formation of a shock in a gas. Aimed at a broad audience, this book provides the mathematical tools for understanding singularities and explains the many common features in their mathematical structure. Part I introduces the main concepts and techniques, using the most elementary mathematics possible so that it can be followed by readers with only a general background in differential equations. Parts II and III require more specialised methods of partial differential equations, complex analysis and asymptotic techniques. The book may be used for advanced fluid mechanics courses and as a complement to a general course on applied partial differential equations.

  16. Formation of Supermassive Black Holes

    Volonteri, Marta


    Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.

  17. Restucturing the Project Work Format

    Dupont, Søren


    The chapter is based on an evaluation of a pedagogical experiment at Roskilde University, the Antology Experiment. The objective of the experiment was to develop and expand the framework for project work through the production of anthologies compiled collectively by a number of project groups....... The novel aspects of the Anthology Experiment were most notably its magnitude and complexity. In this experiment the groups were totalling some 50 students who were working together. The experiment used a well-known publishing format from research, namely the anthology form, which usually focuses....... The organization was complex, the written product changed from project to article format, the students had to concentrate on working in their own project group as well as in the so-called clusters, and the form of exam was radically changed...

  18. Complexity of Formation in Holography

    Chapman, Shira; Myers, Robert C


    It was recently conjectured that the quantum complexity of a holographic boundary state can be computed by evaluating the gravitational action on a bulk region known as the Wheeler-DeWitt patch. We apply this complexity=action duality to evaluate the `complexity of formation' (arXiv:1509.07876, arXiv:1512.04993), i.e., the additional complexity arising in preparing the entangled thermofield double state with two copies of the boundary CFT compared to preparing the individual vacuum states of the two copies. We find that for boundary dimensions $d>2$, the difference in the complexities grows linearly with the thermal entropy at high temperatures. For the special case $d=2$, the complexity of formation is a fixed constant, independent of the temperature. We compare these results to those found using the complexity=volume duality.

  19. Star Cluster Formation and Feedback

    Krumholz, Mark R; Arce, Hector G; Dale, James E; Gutermuth, Robert; Klein, Richard I; Li, Zhi-Yun; Nakamura, Fumitaka; Zhang, Qizhou


    Stars do not generally form in isolation. Instead, they form in clusters, and in these clustered environments newborn stars can have profound effects on one another and on their parent gas clouds. Feedback from clustered stars is almost certainly responsible for a number of otherwise puzzling facts about star formation: that it is an inefficient process that proceeds slowly when averaged over galactic scales; that most stars disperse from their birth sites and dissolve into the galactic field over timescales $\\ll 1$ Gyr; and that newborn stars follow an initial mass function (IMF) with a distinct peak in the range $0.1 - 1$ $M_\\odot$, rather than an IMF dominated by brown dwarfs. In this review we summarize current observational constraints and theoretical models for the complex interplay between clustered star formation and feedback.

  20. Formation of polar ring galaxies

    Bournaud, F


    Polar ring galaxies are peculiar systems in which a gas rich, nearly polar ring surrounds an early-type or elliptical host galaxy. Two formation scenarios for these objects have been proposed: they are thought to form either in major galaxy mergers or by tidal accretion of the polar material from a gas rich donor galaxy. Both scenarios are studied through N-body simulations including gas dynamics and star formation. Constraints on physical parameters are drawn out, in order to determine which scenario is the most likely to occur. Polar ring galaxies from each scenario are compared with observations and we discuss whether the accretion scenario and the merging scenario account for observational properties of polar ring galaxies. The conclusion of this study is that the accretion scenario is both the most likely and the most supported by observations. Even if the merging scenario is rather robust, most polar ring galaxies are shown to be the result of tidal gas accretion events.

  1. Cophasing the Planet Formation Imager

    Petrov, Romain G; Elhalkouj, Thami; Monnier, John; Ireland, Michael; Kraus, Stefan


    The Planet Formation Imager (PFI) is a project for a very large optical interferometer intended to obtain images of the planet formation process at scales as small as the Hill sphere of giant exoplanets. Its main science instruments will work in the thermal infrared but it will be cophased in the near infrared, where it requires also some capacity for scientific imaging. PFI imaging and resolution specifications imply an array of 12 to 20 apertures and baselines up to a few kilometers cophased at near infrared coherent magnitudes as large as 10. This paper discusses various cophasing architectures and the corresponding minimum diameter of individual apertures, which is the dominant element of PFI cost estimates. From a global analysis of the possible combinations of pairwise fringe sensors, we show that conventional approaches used in current interferometers imply the use of prohibitively large telescopes and we indicate the innovative strategies that would allow building PFI with affordable apertures smaller...

  2. New Paradigms For Asteroid Formation

    Johansen, Anders; Cuzzi, Jeffrey N; Morbidelli, Alessandro; Gounelle, Matthieu


    Asteroids and meteorites provide key evidence on the formation of planetesimals in the Solar System. Asteroids are traditionally thought to form in a bottom-up process by coagulation within a population of initially km-scale planetesimals. However, new models challenge this idea by demonstrating that asteroids of sizes from 100 to 1000 km can form directly from the gravitational collapse of small particles which have organised themselves in dense filaments and clusters in the turbulent gas. Particles concentrate passively between eddies down to the smallest scales of the turbulent gas flow and inside large-scale pressure bumps and vortices. The streaming instability causes particles to take an active role in the concentration, by piling up in dense filaments whose friction on the gas reduces the radial drift compared to that of isolated particles. In this chapter we review new paradigms for asteroid formation and compare critically against the observed properties of asteroids as well as constraints from meteo...

  3. Biofilm formation on abiotic surfaces

    Tang, Lone


    Bacteria can attach to any surface in contact with water and proliferate into complex communities enclosed in an adhesive matrix, these communities are called biofilms. The matrix makes the biofilm difficult to remove by physical means, and bacteria in biofilm can survive treatment with many...... antibiotics, disinfectants and cleaning agents. Biofilms are therefore very difficult to eradicate, and an attractive approach to limit biofilm formation is to reduce bacterial adhesion. In this thesis it was shown that lowering the surface roughness had a greater effect on bacterial retention compared....... The ability to form biofilms, the amount of eDNA produced, and the importance of eDNA for biofilm formation or stability did not correlate and varied from strain to strain. Finally, a method was developed for immobilization of living bacteria for analysis by atomic force microscopy (AFM). AFM is used...

  4. Complexity of formation in holography

    Chapman, Shira; Marrochio, Hugo; Myers, Robert C.


    It was recently conjectured that the quantum complexity of a holographic boundary state can be computed by evaluating the gravitational action on a bulk region known as the Wheeler-DeWitt patch. We apply this complexity=action duality to evaluate the `complexity of formation' [1, 2], i.e. the additional complexity arising in preparing the entangled thermofield double state with two copies of the boundary CFT compared to preparing the individual vacuum states of the two copies. We find that for boundary dimensions d > 2, the difference in the complexities grows linearly with the thermal entropy at high temperatures. For the special case d = 2, the complexity of formation is a fixed constant, independent of the temperature. We compare these results to those found using the complexity=volume duality.

  5. The Chemistry of Planet Formation

    Oberg, Karin I.


    Exo-planets are common, and they span a large range of compositions. The origins of the observed diversity of planetary compositions is largely unconstrained, but must be linked to the planet formation physics and chemistry. Among planets that are Earth-like, a second question is how often such planets form hospitable to life. A fraction of exo-planets are observed to be ‘physically habitable’, i.e. of the right temperature and bulk composition to sustain a water-based prebiotic chemistry, but this does not automatically imply that they are rich in the building blocks of life, in organic molecules of different sizes and kinds, i.e. that they are chemically habitable. In this talk I will argue that characterizing the chemistry of protoplanetary disks, the formation sites of planets, is key to address both the origins of planetary bulk compositions and the likelihood of finding organic matter on planets. The most direct path to constrain the chemistry in disks is to directly observe it. In the age of ALMA it is for the first time possible to image the chemistry of planet formation, to determine locations of disk snowlines, and to map the distributions of different organic molecules. Recent ALMA highlights include constraints on CO snowline locations, the discovery of spectacular chemical ring systems, and first detections of more complex organic molecules. Observations can only provide chemical snapshots, however, and even ALMA is blind to the majority of the chemistry that shapes planet formation. To interpret observations and address the full chemical complexity in disks requires models, both toy models and astrochemical simulations. These models in turn must be informed by laboratory experiments, some of which will be shown in this talk. It is thus only when we combine observational, theoretical and experimental constraints that we can hope to characterize the chemistry of disks, and further, the chemical compositions of nascent planets.

  6. Hydrodynamics of catheter biofilm formation

    Sotolongo-Costa, Oscar; Rodriguez-Perez, Daniel; Martinez-Escobar, Sergio; Fernandez-Barbero, Antonio


    A hydrodynamic model is proposed to describe one of the most critical problems in intensive medical care units: the formation of biofilms inside central venous catheters. The incorporation of approximate solutions for the flow-limited diffusion equation leads to the conclusion that biofilms grow on the internal catheter wall due to the counter-stream diffusion of blood through a very thin layer close to the wall. This biological deposition is the first necessary step for the subsequent bacteria colonization.

  7. Star Formation in MUSCEL Galaxies

    Young, Jason; Kuzio de Naray, Rachel; Wang, Sharon Xuesong


    We present preliminary star-formation histories for a subset of the low surface brightness (LSB) galaxies in the MUSCEL (MUltiwavelength observations of the Structure, Chemistry, and Evolution of LSB galaxies) program. These histories are fitted against ground-based IFU spectra in tandem with space-based UV and IR photometry. MUSCEL aims to use these histories along with kinematic analyses to determine the physical processes that have caused the evolution of LSB galaxies to diverge from their high surface brightness counterparts.

  8. Cosmological models of galaxy formation

    Menci, N.

    I review the present status of galaxy formation models within a cosmological framework. I focus on semi-analytic models based on the Cold Dark Matter scenario, discussing the role of the different physical process involving dark matter and baryons in determining the observed statistical properties of galaxies and their dependence on cosmic time and on environment evolution. I will highlight some present problems and briefly present the main effects of assuming a Warm Dark Matter scenario.

  9. Illusory contour formation survives crowding.

    Lau, Jonathan Siu Fung; Cheung, Sing-Hang


    Flanked objects are difficult to identify using peripheral vision due to visual crowding, which limits conscious access to target identity. Nonetheless, certain types of visual information have been shown to survive crowding. Such resilience to crowding provides valuable information about the underlying neural mechanism of crowding. Here we ask whether illusory contour formation survives crowding of the inducers. We manipulated the presence of illusory contours through the (mis)alignment of the four inducers of a Kanizsa square. In the inducer-aligned condition, the observers judged the perceived shape (thin vs. fat) of the illusory Kanizsa square, manipulated by small rotations of the inducers. In the inducer-misaligned condition, three of the four inducers (all except the upper-left) were rotated 90°. The observers judged the orientation of the upper-left inducer. Crowding of the inducers worsened observers' performance significantly only in the inducer-misaligned condition. Our findings suggest that information for illusory contour formation survives crowding of the inducers. Crowding happens at a stage where the low-level featural information is integrated for inducer orientation discrimination, but not at a stage where the same information is used for illusory contour formation.

  10. Formation of Kuiper Belt Binaries

    Goldreich, P; Sari, R; Goldreich, Peter; Lithwick, Yoram; Sari, Re'em


    It appears that at least several percent of large Kuiper belt objects are members of wide binaries. Physical collisions are too infrequent to account for their formation. Collisionless gravitational interactions are more promising. These provide two channels for binary formation. In each, the initial step is the formation of a transient binary when two large bodies penetrate each other's Hill spheres. Stabilization of a transient binary requires that it lose energy. Either dynamical friction due to small bodies or the scattering of a third large body can be responsible. Our estimates favor the former, albeit by a small margin. We predict that most objects of size comparable to those currently observed in the Kuiper belt are members of multiple systems. More specifically, we derive the probability that a large body is a member of a binary with semi-major axis of order a. The probability depends upon sigma, the total surface density, Sigma, the surface density of large bodies having radius R, and theta=10^-4, t...

  11. Galaxy Formation Spanning Cosmic History

    Benson, Andrew J


    Over the past several decades, galaxy formation theory has met with significant successes. In order to test current theories thoroughly we require predictions for as yet unprobed regimes. To this end, we describe a new implementation of the Galform semi-analytic model of galaxy formation. Our motivation is the success of the model described by Bower et al. in explaining many aspects of galaxy formation. Despite this success, the Bower et al. model fails to match some observational constraints and certain aspects of its physical implementation are not as realistic as we would like. The model described in this work includes substantially updated physics, taking into account developments in our understanding over the past decade, and removes certain limiting assumptions made by this (and most other) semi-analytic models. This allows it to be exploited reliably in high-redshift and low mass regimes. Furthermore, we have performed an exhaustive search of model parameter space to find a particular set of model para...

  12. Star Formation in Satellite Galaxies

    Gutíerrez, C M; Funes, J G; Ribeiro, M B


    We present narrow-band observations of the H$\\alpha$ emission in a sample of 31 satellite orbiting isolated giant spiral galaxies. The sample studied spans the range $-19formation rates are 0.68 and 3.66 M$_\\sun$ yr$^{-1}$ respectively. Maps of the spatial distribution of ionized gas are presented. The star-forming regions show a rich structure in which frequently discrete complexes are imposed over more diffuse structures. In general, the current star formation rates are smaller that the mean values in the past obtained from the current stellar content; this probably indicates a declining rhythm with time in the generation of new stars. However, the reserve of gas is enough to continue fueling the current levels of star formation activity for at least another Hubble time. Four of the o...

  13. Positronium formation in various polyimides

    Okamoto, Ken-ichi; Tanaka, Kazuhiro; Katsube, Mikio; Sueoka, Osamu; Ito, Yasuo (Yamaguchi Univ., Ube (Japan). Faculty of Engineering Tokyo Univ. (Japan). Research Center for Nuclear Science and Technology)


    Positronium (Ps) formation in various polyimides has been studied. It has been found that Ps yield is zero or small in the polyimides having pyromellitic dianhydride (PMDA) and 3,3[sup '],4,4[sup ']-benzophenonetetracarboxylic dianhydride (BTDA) as acid anhydride moiety, while those having 3,3[sup '],4,4[sup ']-biphenyltetracarboxylic dianhydride (BPDA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) form Ps with intensities up to about 20%. This difference is well correlated with the electron affinity of these moieties: PMDA > BTDA > BPDA [approx] 6FDA. In another experiment o-Ps yields and its lifetimes were measured in benzene solutions of monomeric model compounds (imide compounds prepared from n-butylamine and the acid anhydrides). It has been found that the model compounds from PMDA and BTDA both inhibit Ps formation and quench o-Ps lifetimes but that those from BPDA and 6FDA have neither the inhibition nor the quenching effects. The results show that the spur model is applicable for Ps formation in the polyimides. (Author).

  14. Positronium formation in various polyimides

    Okamoto, Ken-ichi; Tanaka, Kazuhiro; Katsube, Mikio; Sueoka, Osamu; Ito, Yasuo


    Positronium (Ps) formation in various polyimides has been studied. It has been found that Ps yield is zero or small in the polyimides having pyromellitic dianhydride (PMDA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) as acid anhydride moiety, while those having 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 2,2- bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) form Ps with intensities up to about 20%. This difference is well correlated with the electron affinity of these moieties: PMDA > BTDA > BPDA ˜ 6FDA. In another experiment o-Ps yields and its lifetimes were measured in benzene solutions of monomeric model compounds (imide compounds prepared from n-butylamine and the acid anhydrides). It has been found that the model compounds from PMDA and BTDA both inhibit Ps formation and quench o-Ps lifetimes but that those from BPDA and 6FDA have neither the inhibition nor the quenching effects. The results show that the spur model is applicable for Ps formation in the polyimides.

  15. Star Formation in Tadpole Galaxies

    Casiana Muñoz-Tuñon


    Full Text Available Tadpole Galaxies look like a star forming head with a tail structure to the side. They are also named cometaries. In a series of recent works we have discovered a number of issues that lead us to consider them extremely interesting targets. First, from images, they are disks with a lopsided starburst. This result is rmly  established with long slit spectroscopy in a nearby representative sample. They rotate with the head following the rotation pattern but displaced from the rotation center. Moreover, in a search for extremely metal poor (XMP galaxies, we identied tadpoles as the dominant shapes in the sample - nearly 80% of the local XMP galaxies have a tadpole morphology. In addition, the spatially resolved analysis of the metallicity shows the remarkable result that there is a metallicity drop right at the position of the head. This is contrary to what intuition would say and dicult to explain if star formation has happened from gas processed in the disk. The result could however be understood if the star formation is driven by pristine gas falling into the galaxy disk. If conrmed, we could be unveiling, for the rst time, cool  ows in action in our nearby world. The tadpole class is relatively frequent at high redshift - 10% of resolvable galaxies in the Hubble UDF but less than 1% in the local Universe. They are systems that could track cool ows and test models of galaxy formation.

  16. Gravity, Turbulence, and Star Formation

    Elmegreen, B G


    The azimuthal power spectra of optical emission from star formation and dust in spiral galaxies resembles the azimuthal power spectra of HI emission from the LMC. These and other power spectra of whole galaxies all resemble that of velocity in incompressible Kolmogorov turbulence. The reasons for this are unknown but it could be simply that star and cloud formation are the result of a mixture of processes and each gives a power spectrum similar to Kolmogorov turbulence, within the observable errors. The important point is that star and cloud formation are not random but are correlated over large distances by forces that span several orders of magnitude in scale. These forces are probably the usual combination of self-gravity, turbulence, and compression from stellar winds and supernovae, but they have to work in concert to create the structures we see in galaxies. In addition, the identification of flocculant spirals with swing amplified instabilities opens the possibility that a high fraction of turbulence i...

  17. NSDF: Neuroscience Simulation Data Format.

    Ray, Subhasis; Chintaluri, Chaitanya; Bhalla, Upinder S; Wójcik, Daniel K


    Data interchange is emerging as an essential aspect of modern neuroscience. In the areas of computational neuroscience and systems biology there are multiple model definition formats, which have contributed strongly to the development of an ecosystem of simulation and analysis tools. Here we report the development of the Neuroscience Simulation Data Format (NSDF) which extends this ecosystem to the data generated in simulations. NSDF is designed to store simulator output across scales: from multiscale chemical and electrical signaling models, to detailed single-neuron and network models, to abstract neural nets. It is self-documenting, efficient, modular, and scalable, both in terms of novel data types and in terms of data volume. NSDF is simulator-independent, and can be used by a range of standalone analysis and visualization tools. It may also be used to store variety of experimental data. NSDF is based on the widely used HDF5 (Hierarchical Data Format 5) specification and is open, platform-independent, and portable.

  18. Star Formation in Molecular Clouds

    Krumholz, Mark R


    Star formation is one of the least understood processes in cosmic evolution. It is difficult to formulate a general theory for star formation in part because of the wide range of physical processes involved. The interstellar gas out of which stars form is a supersonically turbulent plasma governed by magnetohydrodynamics. This is hard enough by itself, since we do not understand even subsonic hydrodynamic turbulence very well, let alone supersonic non-ideal MHD turbulence. However, the behavior of star-forming clouds in the ISM is also obviously influenced by gravity, which adds complexity, and by both continuum and line radiative processes. Finally, the behavior of star-forming clouds is influenced by a wide variety of chemical processes, including formation and destruction of molecules and dust grains (which changes the thermodynamic behavior of the gas) and changes in ionization state (which alter how strongly the gas couples to magnetic fields). As a result of these complexities, there is nothing like a g...

  19. Hypothesis Formation, Paradigms, and Openness

    Conrad P. Pritscher


    Full Text Available A part of hypothesis formation, while necessary for scientific investigation, is beyond direct observation. Powerful hypothesis formation is more than logical and is facilitated by mind­opening. As Percy Bridgeman, Nobel laureate, said, science is: “Nothing more than doing one's damnedest with one's mind, no holds barred.” This paper suggests more open schooling helps generate more open hypothesizing which helps one do one's damnedest with one's mind. It is hypothesized that a more open process of hypothesis formation may help schools and society forge new ways of living and learning so that more people more often can do their damnedest with their mind. This writing does not offer a new paradigm but rather attempts to elaborate on the notion that new paradigms are difficult to form without openness to what was previously quasi­unthinkable. More on these topics and issues is included in the author's Reopening Einstein's Thought: About What Can't Be Learned From Textbooks ­­to be published by Sense Publishers in June 2008.

  20. Kinetic competition during glass formation

    Perepezko, J.H., E-mail: [University of Wisconsin-Madison, Department of Materials Science and Engineering, 1509 University Ave., Madison, WI 53706 (United States); Santhaweesuk, C.; Wang, J.Q. [University of Wisconsin-Madison, Department of Materials Science and Engineering, 1509 University Ave., Madison, WI 53706 (United States); Imhoff, S.D. [Los Alamos National Laboratory, Materials Science and Technology Div., Los Alamos, NM 87545 (United States)


    Highlights: • The kinetics of glass formation has been elucidated in an Fe and Au-base alloy. • A critical cooling rate range should be considered for glass formation. • Wedge casting, calorimetry and upquenching data are used to model TTT curves. - Abstract: For vitrification of an alloy melt during cooling there is a kinetic competition with the nucleation and growth of metastable and stable crystalline phases. Many of the measures of glass forming ability (GFA) attempt to capture some of the features of the kinetic competition, but the GFA metrics are static measures and the kinetic processes are dynamic in nature. In fact, the critical cooling rate for glass formation should be viewed in terms of a critical cooling rate range to acknowledge the stochastic nature of crystal nucleation behavior. Direct measurements of the critical cooling rate range confirm this behavior and also provide useful input for kinetics analysis. Usually kinetics analyses are based upon crystallization behavior that is measured either isothermally or upon heating to temperatures near the crystallization onset, T{sub x} and the results are extrapolated to much higher temperatures. This practice is based upon a number of assumptions about transport behavior in the undercooled liquid. With rapid up-quenching of amorphous samples, the high temperature crystallization behavior can be measured and used to refine the kinetics analysis and provide useful insight on the kinetic competition and glass forming ability.

  1. Interactions, Starbursts, and Star Formation

    Johan H. Knapen


    Full Text Available We study how interactions between galaxies affect star formation within them by considering a sample of almost 1500 of the nearest galaxies, all within a distance of ∼45 Mpc. We use the far-IR emission to define the massive star formation rate (SFR, and then normalise the SFR by the stellar mass of the galaxy to obtain the specific star formation rate (SSFR. We explore the distribution of (SSFR with morphological type and with stellar mass. We calculate the relative enhancement of SFR and SSFR for each galaxy by normalising them by the median SFR and SSFR values of individual control samples of similar non-interacting galaxies. We find that both the median SFR and SSFR are enhanced in interacting galaxies, and more so as the degree of interaction is higher. The increase is moderate, reaching a maximum of a factor of 1.9 for the highest degree of interaction (mergers. While the SFR and SSFR are enhanced statistically by interactions, in many individual interacting galaxies they are not enhanced at all. Our study is based on a representative sample of nearby galaxies and should be used to place constraints on studies based on samples of galaxies at larger distances.

  2. Formation mechanisms of metal colloids

    Halaciuga, Ionel

    Highly dispersed uniform metallic particles are widely used in various areas of technology and medicine and are likely to be incorporated into many other applications in the future. It is commonly accepted that size, shape and composition of the particles represent critical factors in most applications. Thus, understanding the mechanisms of formation of metal particles and the ways to control the physical (e.g. shape, size) and chemical (e.g. composition) properties is of great importance. In the current research, the formation of uniform silver spheres is investigated experimentally. The parameters that influence the formation of silver particles when concentrated iso-ascorbic acid and silver-polyamine complex solutions are rapidly mixed were studied in the absence of dispersants. We found that by varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, the size of the resulting silver particles can be varied in a wide range (0.08--1.5 microm). The silver particles were formed by aggregation of nanosize subunits as substantiated by both electron microscopy and X-ray diffraction techniques and by the vivid rapid color changes during the chemical precipitation process. From the practical standpoint, the goal of this research was to prepare well dispersed spherical silver particles having a relatively smooth surface and a diameter of about 1 microm to satisfy the demands of the current electronic materials market. A two stage particle growth model previously developed to explain the narrow size distribution occurring in synthesis of gold spheres was applied to the present experimental system, and the parameters that control the size distribution characteristics were identified. The kinetic parameter required to match the final particle size was found to be in agreement with the one used previously in modeling formation of gold spheres, suggesting that similar kinetics governs the

  3. Core formation in silicate bodies

    Nimmo, F.; O'Brien, D. P.; Kleine, T.


    Differentiation of a body into a metallic core and silicate mantle occurs most efficiently if temperatures are high enough to allow at least the metal to melt [1], and is enhanced if matrix deformation occurs [2]. Elevated temperatures may occur due to either decay of short-lived radio-isotopes, or gravitational energy release during accretion [3]. For bodies smaller than the Moon, core formation happens primarily due to radioactive decay. The Hf-W isotopic system may be used to date core formation; cores in some iron meteorites and the eucrite parent body (probably Vesta) formed within 1 My and 1-4~My of solar system formation, respectively [4]. These formation times are early enough to ensure widespread melting and differentiation by 26Al decay. Incorporation of Fe60 into the core, together with rapid early mantle solidification and cooling, may have driven early dynamo activity on some bodies [5]. Iron meteorites are typically depleted in sulphur relative to chondrites, for unknown reasons [6]. This depletion contrasts with the apparently higher sulphur contents of cores in larger planetary bodies, such as Mars [7], and also has a significant effect on the timing of core solidification. For bodies of Moon-size and larger, gravitational energy released during accretion is probably the primary cause of core formation [3]. The final stages of accretion involve large, stochastic collisions [8] between objects which are already differentiated. During each collision, the metallic cores of the colliding objects merge on timescales of a few hours [9]. Each collision will reset the Hf-W isotopic signature of both mantle and core, depending on the degree to which the impactor core re-equilibrates with the mantle of the target [10]. The re-equilibration efficiency depends mainly on the degree to which the impactor emulsifies [11], which is very uncertain. Results from N-body simulations [8,12] suggest that significant degrees of re- equilibration are required [4,10]. Re

  4. MHD turbulence, cloud formation and star formation in the ISM

    Vázquez-Semadeni, E; Pouquet, A


    We discuss the role of turbulence in cloud and star formation, as observed in numerical simulations of the interstellar medium. Turbulent compression at the interfaces of colliding gas streams is responsible for the formation of intermediate (\\simlt 100 pc) and small clouds (a few tens of pc), although the smallest clouds can also form from fragmentation of expanding shells around stellar heating centers. The largest cloud complexes (several hundred pc) seem to form by slow, gravitational instability-driven merging of individual clouds, which can actually be described as a large-scale tendency towards homogenization of the flow due to gravity rather than cloud collisions. These mechanisms operate as well in the presence of a magnetic field and rotation, although slight variations on the compressibility and cloud morphology are present which depend on the strength and topology of the field. In summary, the role of turbulence in the life-cycle of clouds appears to be twofold: small-scale modes contribute to clo...

  5. On-Going Galaxy Formation

    Braine, Jonathan; Duc, P.-A.; Lisenfeld, U.; Charmandaris, V.; Vallejo, O.; Leon, S.; Brinks, E.


    We investigate the process of galaxy formation as can be observed in the only currently forming galaxies - the so-called Tidal Dwarf Galaxies, hereafter TDGs - through observations of the molecular gas detected via its CO (Carbon Monoxide) emission. These objects are formed of material torn off of the outer parts of a spiral disk due to tidal forces in a collision between two massive galaxies. Molecular gas is a key element in the galaxy formation process, providing the link between a cloud of gas and a bona fide galaxy. We have detected CO in 8 TDGs (Braine, Lisenfeld, Duc and Leon, 2000: Nature 403, 867; Braine, Duc, Lisenfeld, Charmandaris, Vallejo, Leon and Brinks: 2001, A&A 378, 51), with an overall detection rate of 80%, showing that molecular gas is abundant in TDGs, up to a few 108 M ⊙. The CO emission coincides both spatially and kinematically with the HI emission, indicating that the molecular gas forms from the atomic hydrogen where the HI column density is high. A possible trend of more evolved TDGs having greater molecular gas masses is observed, in accord with the transformation of HI into H2. Although TDGs share many of the properties of small irregulars, their CO luminosity is much greater (factor ˜ 100) than that of standard dwarf galaxies of comparable luminosity. This is most likely a consequence of the higher metallicity (≳sim 1/3 solar) of TDGs which makes CO a good tracer of molecular gas. This allows us to study star formation in environments ordinarily inaccessible due to the extreme difficulty of measuring the molecular gas mass. The star formation efficiency, measured by the CO luminosity per Hα flux, is the same in TDGs and full-sized spirals. CO is likely the best tracer of the dynamics of these objects because some fraction of the HI near the TDGs may be part of the tidal tail and not bound to the TDG. Although uncertainties are large for individual objects, as the geometry is unknown, our sample is now of eight detected objects

  6. Mechanism of formation of hydantoins

    Worman, J.J.; Uhrich, K.; Olson, E.; Diehl, J.; Farnum, S.; Hawthorne, S.


    Hydantoins, (I), are biologically active compounds which occur in nature and have been isolated from such sources as sugar beets and butterfly wings. Synthetic analogs have found widespread use as anticonvulsant drugs, bacteriocides, stabilizers in photographic film, and in the preparation of high temperature epoxy resins. Uses, preparation, and reactions of hydantoins have been extensively studied and are reported elsewhere. Recently a number of hydantoin isomers have been detected and identified in coal gasification condensate water from the gasification of Indian Head (ND) lignite in a slagging fixed bed gasifier. The hydantoins constitute a major portion of the organics in the condensate water. In generation the concentrations of hydantoins found in the condensate water from an ash gasifier are smaller than those found from the slagging process. Lignite coal reacting in a slagging gasifier gives the largest concentration of hydantoins in the condensate water. The major isomer in the coal gasification condensate water is 5,5-dimethylhydantoin (DMH). DMH is formed from individual species (acetone, cyanide, ammonia, and carbonate) in the condensate water and does not form directly in the gasifier. The rate of formation of DMH was first order in all of the reactants as expressed by the equation: Rate of formation of DMH = (Acetone) (HCN) (NH/sub 3/) (CO/sub 2/). This kinetic data is valuable in predicting the rate of formation of DMH in coal gasification condensate water, provided the model is applicable. A mechanism consistent with the kinetic data and partially verified by others is shown in Scheme 1. 13 refs.


    Umesh P.GUPTA; C.S.P.OJHA; Nayan SHARMA


    Submerged vanes are submerged foils constructed in a river at an angle of attack to induce horizontal circulation in the downstream flow. The initial height of vanes is 0.2 - 0.4 times the local water depth (d) at the design stage. Its length expressed as a multiple of the height to length ratio (H/L) normally is 0.25 to 0.5. With the use of a submerged vane in straight channels, dikes (heaps of sediment) were formed downstream. At an optimal angle of attack of 40o and at a Froude number of 0.25, the formation of the dike starts at some distance from the trailing edge of the rectangular and trapezoidal submerged vanes with a collar. A significant scour hole results at the trailing edge of a vane with a collar. A typical dike formed along the vane on the suction side with a symmetric bell-shaped profile. The dike formation phenomenon triggered by a vane close to the bank-line at a flow with a relatively higher Froude number, such as 0.25, does not seem to follow a straight alignment, but has a sort of curvilinear shape bent towards the suction side. The dike formation process for a flow with a smaller Froude number, such as 0.13, is observed to not be appreciable. With the same installation height of H, a vane without a collar was dislodged by the flow at a Froude number of 0.25, whereas it was stable at a Froude number of 0.13.

  8. Dark Matter and Galaxy Formation

    Primack, Joel R.


    The four lectures that I gave in the XIII Ciclo de Cursos Especiais at the National Observatory of Brazil in Rio in October 2008 were (1) a brief history of dark matter and structure formation in a ΛCDM universe; (2) challenges to ΛCDM on small scales: satellites, cusps, and disks; (3) data on galaxy evolution and clustering compared with simulations; and (4) semi-analytic models. These lectures, themselves summaries of much work by many people, are summarized here briefly. The slides [1] contain much more information.

  9. Dark Matter and Galaxy Formation

    Primack, Joel R


    The four lectures that I gave in the XIII Ciclo de Cursos Especiais at the National Observatory of Brazil in Rio in October 2008 were (1) a brief history of dark matter and structure formation in a LambdaCDM universe; (2) challenges to LambdaCDM on small scales: satellites, cusps, and disks; (3) data on galaxy evolution and clustering compared with simulations; and (4) semi-analytic models. These lectures, themselves summaries of much work by many people, are summarized here briefly.

  10. Quality guidance and quality formation

    Poulsen, Carsten Stig; Juhl, Hans Jørn; Kristensen, Kai


    This paper presents an extension of the quality guidance model of Steenkamp and van Trijp that includes consumer quality formation processes. Quality expectations and quality experiences are seen as antecedents of perceived overall product quality conceptual model is applied using LISREL to a data...... set on Danish butter cookies. Five plausible models of the relation between expectation, experience and perceived product quality are estimated. Finally one model is selected on the basis of three criteria: chi-square, RMSEA and AIC: The results show a model where expectations are indirectly related...... to perceived quality through experience. Udgivelsesdato: APR...

  11. Adsorption-induced step formation

    Thostrup, P.; Christoffersen, Ebbe; Lorensen, Henrik Qvist


    Through an interplay between density functional calculations, Monte Carlo simulations and scanning tunneling microscopy experiments, we show that an intermediate coverage of CO on the Pt(110) surface gives rise to a new rough equilibrium structure with more than 50% step atoms. CO is shown to bin...... so strongly to low-coordinated Pt atoms that it can break Pt-Pt bonds and spontaneously form steps on the surface. It is argued that adsorption-induced step formation may be a general effect, in particular at high gas pressures and temperatures....

  12. IRIG Serial Time Code Formats


    by Secretariat Range Commanders Council U.S. Army White Sands Missile Range, New Mexico 88002-5110 This page intentionally left blank. IRIG...New Mexico 88002-5110 Phone: DSN 258-1107 Com (575) 678-1107 Fax: DSN 258-7519 Com (575) 678-7519 Email: G. It should be noted that this standard reflects the present state of the art in serial time code formatting and is not intended to constrain

  13. Graphene mediated magnetic domain formation

    Tanabe, Iori; Wang, Yi; Kong, Lingmei; Binek, Christian; Pasquale, Frank; Cao, Yuan; Dong, Bin; Kelber, Jeffry; Dowben, Peter


    Both graphene on Co and graphene on Co3O4/Co samples were investigate by the Raman spectroscopy and longitudinal magneto-optic Kerr effect (MOKE). While the graphene on Co (111) bilayer thin films exhibited high remnant magnetization in plane easy axis ferromagnetism, the graphene/Co3O4/Co trilayers exhibited little remnant magnetization. The latter is due to formation of a complex multidomain state at zero applied field. The role of graphene and Co3O4 will be discussed.

  14. The formation of interstellar jets

    Tenorio-Tagle, G.; Canto, J.; Rozyczka, M.


    The formation of interstellar jets by convergence of supersonic conical flows and the further dynamical evolution of these jets are investigated theoretically by means of numerical simulations. The results are presented in extensive graphs and characterized in detail. Strong radiative cooling is shown to result in jets with Mach numbers 2.5-29 propagating to lengths 50-100 times their original widths, with condensation of swept-up interstellar matter at Mach 5 or greater. The characteristics of so-called molecular outflows are well reproduced by the simulations of low-Mach-number and quasi-adiabatic jets.

  15. The multifaceted planetesimal formation process

    Johansen, Anders; Blum, Jürgen; Tanaka, Hidekazu


    Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Left-over planetesimals in the form of asteroids, trans...... micrometer-sized dust and ice to bodies which can undergo run-away accretion. The latter ranges in size from 1 km to 1000 km, dependent on the planetesimal eccentricity excited by turbulent gas density fluctuations. Particles face many barriers during this growth, arising mainly from inefficient sticking...

  16. Branch formation during organ development

    Gjorevski, Nikolce; Nelson, Celeste M.


    Invertebrates and vertebrates use branching morphogenesis to build epithelial trees to maximize the surface area of organs within a given volume. Several molecular regulators of branching have recently been discovered, a number of which are conserved across different organs and species. Signals that control branching at the cellular and tissue levels are also starting to emerge, and are rapidly unveiling the physical nature of branch development. Here we discuss the molecular, cellular and physical processes that govern branch formation and highlight the major outstanding questions in the field. PMID:20890968

  17. Austenite formation during intercritical annealing

    A. Lis; J. Lis


    Purpose: of this paper is the effect of the soft annealing of initial microstructure of the 6Mn16 steel on the kinetics of the austenite formation during next intercritical annealing.Design/methodology/approach: Analytical TEM point analysis with EDAX system attached to Philips CM20 was used to evaluate the concentration of Mn, Ni and Cr in the microstructure constituents of the multiphase steel and mainly Bainite- Martensite islands.Findings: The increase in soft annealing time from 1-60 hou...

  18. Massive neutrinos and galaxy formation

    Ma Chung Pei


    We report the most recent results from high-resolution numerical simulations of structure formation in two flat cold+hot dark matter models with neutrino mass densities \\onu=0.2 and 0.3. We find that structure forms too late in all CDM+HDM models with \\onu>0.2 to account for the amount of dense neutral gas in high-redshift damped Lyman-\\alpha systems. The \\onu=0.2 model at z\\approx0 provides a better match to observations than the pure CDM model.

  19. Quality guidance and quality formation

    Poulsen, Carsten Stig; Juhl, Hans Jørn; Kristensen, Kai


    This paper presents an extension of the quality guidance model of Steenkamp and van Trijp that includes consumer quality formation processes. Quality expectations and quality experiences are seen as antecedents of perceived overall product quality conceptual model is applied using LISREL to a data...... set on Danish butter cookies. Five plausible models of the relation between expectation, experience and perceived product quality are estimated. Finally one model is selected on the basis of three criteria: chi-square, RMSEA and AIC: The results show a model where expectations are indirectly related...... to perceived quality through experience. Udgivelsesdato: APR...

  20. Formation flight astronomical survey telescope

    Tsunemi, Hiroshi


    Formation Flight Astronomical Survey Telescope (FFAST) is a project for hard X-ray observation. It consists of two small satellites; one (telescope satellite) has a super mirror covering the energy range up to 80 keV while the other (detector satellite) has an scintillator deposited CCD (SDCCD) having good spatial resolution and high efficiency up to 100 keV. Two satellites will be put into individual Kepler orbits forming an X-ray telescope with a focal length of 20 m. They will be not in pointing mode but in survey mode to cover a large sky region.