WorldWideScience

Sample records for ahwaz sandstone member

  1. Sandstone-body and shale-body dimensions in a braided fluvial system: Salt wash sandstone member (Morrison formation), Garfield County, Utah

    Science.gov (United States)

    Robinson, J.W.; McCabea, P.J.

    1997-01-01

    Excellent three-dimensional exposures of the Upper Jurassic Salt Wash Sandstone Member of the Morrison Formation in the Henry Mountains area of southern Utah allow measurement of the thickness and width of fluvial sandstone and shale bodies from extensive photomosaics. The Salt Wash Sandstone Member is composed of fluvial channel fill, abandoned channel fill, and overbank/flood-plain strata that were deposited on a broad alluvial plain of low-sinuosity, sandy, braided streams flowing northeast. A hierarchy of sandstone and shale bodies in the Salt Wash Sandstone Member includes, in ascending order, trough cross-bedding, fining-upward units/mudstone intraclast conglomerates, singlestory sandstone bodies/basal conglomerate, abandoned channel fill, multistory sandstone bodies, and overbank/flood-plain heterolithic strata. Trough cross-beds have an average width:thickness ratio (W:T) of 8.5:1 in the lower interval of the Salt Wash Sandstone Member and 10.4:1 in the upper interval. Fining-upward units are 0.5-3.0 m thick and 3-11 m wide. Single-story sandstone bodies in the upper interval are wider and thicker than their counterparts in the lower interval, based on average W:T, linear regression analysis, and cumulative relative frequency graphs. Multistory sandstone bodies are composed of two to eight stories, range up to 30 m thick and over 1500 m wide (W:T > 50:1), and are also larger in the upper interval. Heterolithic units between sandstone bodies include abandoned channel fill (W:T = 33:1) and overbank/flood-plain deposits (W:T = 70:1). Understanding W:T ratios from the component parts of an ancient, sandy, braided stream deposit can be applied in several ways to similar strata in other basins; for example, to (1) determine the width of a unit when only the thickness is known, (2) create correlation guidelines and maximum correlation lengths, (3) aid in interpreting the controls on fluvial architecture, and (4) place additional constraints on input variables to

  2. Fracture network of the Ferron Sandstone Member of the Mancos Shale, east-central Utah, USA

    Science.gov (United States)

    Condon, S.M.

    2003-01-01

    The fracture network at the outcrop of the Ferron Sandstone Member of the Mancos Shale was studied to gain an understanding of the tectonic history of the region and to contribute data to studies of gas and water transmissivity related to the occurrence and production of coal-bed methane. About 1900 fracture readings were made at 40 coal outcrops and 62 sandstone outcrops in the area from Willow Springs Wash in the south to Farnham dome in the north of the study area in east-central Utah.Two sets of regional, vertical to nearly vertical, systematic face cleats were identified in Ferron coals. A northwest-striking set trends at a mean azimuth of 321??, and a northeast-striking set has a mean azimuth of 55??. Cleats were observed in all coal outcrops examined and are closely spaced and commonly coated with thin films of iron oxide.Two sets of regional, systematic joint sets in sandstone were also identified and have mean azimuths of 321?? and 34??. The joints of each set are planar, long, and extend vertically to nearly vertically through multiple beds; the northeast-striking set is more prevalent than the northwest-striking set. In some places, joints of the northeast-striking set occur in closely spaced clusters, or joint zones, flanked by unjointed rock. Both sets are mineralized with iron oxide and calcite, and the northwest-striking set is commonly tightly cemented, which allowed the northeast-striking set to propagate across it. All cleats and joints of these sets are interpreted as opening-mode (mode I) fractures. Abutting relations indicate that the northwest-striking cleats and joints formed first and were later overprinted by the northeast-striking cleats and joints. Burial curves constructed for the Ferron indicate rapid initial burial after deposition. The Ferron reached a depth of 3000 ft (1000 m) within 5.2 million years (m.y.), and this is considered a minimum depth and time for development of cleats and joints. The Sevier orogeny produced southeast

  3. Diagenesis of Paleogene sandstone from Kong 1 Member of Southern Kongdian in Huanghua depression

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Huanghua depression is one of the richest areas in petroleum and natural gas in China. The Paleogene mainly consists of sandstone with facies of river, delta, fan delta and littoral-shallow lacustrine. Diagenesis played an important role in the properties of reservoir rocks. Applying X-ray diffraction, on the basis of analyzing many cores and thin sections, the authors studied diagenesis of Paleogene sandstone reservoir rocks in kongl Menber of southern Kongdian in Huanghua depression. Diagenetic complexity shows that the sandstone in this area underwent compaction, cementation, isolation, recrystallization during the burying of sediments, and the first three compose the major diagenesis. The compaction and cementation led to decreasing porosity, and the solution of unsteady minerals also results in increasing in porosity.

  4. Sandstone-body structures and ephemeral stream processes in the Dinosaur Canyon Member, Moenave Formation (Lower Jurassic), Utah, U.S.A.

    Science.gov (United States)

    Olsen, Henrik

    1989-02-01

    Studies of fluvial sandstone-body structures in the Lower Jurassic Dinosaur Canyon Member suggest a threefold subdivision of the ephemeral stream deposits. Sandstone-sheets with interbedded siltstones are less than 1 m thick and laterally extensive for hundreds of metres. They are interpreted as sheetflood deposits. Simple channel sandstone-bodies are a few metres thick and a few tens of metres wide. They reflect solitary channel incision, episodic migration and plugging. Multistorey channel sandstone-bodies are a few metres thick and laterally extensive for hundreds of metres. They are composed of several channel-shaped storeys and exhibit only local incision. The multistorey sandstone-bodies are interpreted as braided ephemeral stream deposits. Two sandstone-sheet subtypes with grooves and mounds, respectively, are interpreted as intermediate between the sheetflood deposits and solitary incised channel deposits on one hand and between sheetflood deposits and braided stream deposits on the other hand. The solitary channels and braided streams are accordingly interpreted to be initiated from sheetfloods through differential erosion and differential deposition, respectively. This model of channel evolution from sheetfloods is probably applicable to other semiarid and arid fluvial environments dominated by surface runoff.

  5. Diagenetic alteration process of chlorite in Tyr Member sandstone, Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Hansen, Jens Peter Vind

    quartz overgrowths, calcite and chlorite and also minor amount of diagenetic K-feldspar. The investigated materials were core samples of Palaeocene sands referred to the Ty Member from the well Rau 1A. Chlorite was formed as pervasive grain-coating cement, but much porosity was still present. In the oil...... zone and deeper, porous samples were later cemented by macro quartz, with larger amounts in the water zone. Chlorite is found in varying amounts in Rau 1A samples. It can be recognized in SEM as a platy or bladed precipitate, which is mostly rich in iron. Chlorite is present in most samples, although...... only in traceable amounts in the samples which are dominated by microquartz cement. There seem to be two chlorite phases: The first phase occurs as rosettes in a grain coating growth pattern. It is partially intergrown with microquartz or forms a dense mixture of small chlorite rosettes and scattered...

  6. Dietary Factors Associated To Obesity In Ahwaz Primary School Pupils

    Directory of Open Access Journals (Sweden)

    Dorosty A.R; Tabatabaei M

    2005-05-01

    Full Text Available Background: Increase in obesity prevalence in recent years are associated to genetics as well environmental and behavioral factors. Change in dietary patterns including fatty and high density energy foods consumption have been reported to be very important. This study aimed to determine dietary factors (daily energy and macronutrient intakes, energy percentage of macronutrient, energy and macronutrient intakes per kilogram body weight, frequency of cola, natural fruit juice drinking, dairy products except cheese, tomato chips, puff, chocolate and fast food consumption and eating speed associated to obesity in Ahwaz primary school pupils. Materials and Methods: Using two stage cluster sampling from 35 Ahwaz primary schools, all 10-11y students who had a BMI 95th percentile of Hosseini et al. (1999 reference, were identified as obese (n=150 and 150 same age and gender pupils (having BMI0.05. macronutrient intakes per kilogram body weight were significantly lower in obese group (p0.05. Obese students used to eat faster (p<0.05. Conclusion: In conclusion, high intakes of energy, protein, carbohydrate, tomato chips and puff and high eating speed were associated to obesity in Ahwaz primary school pupils.

  7. Controls on the Lower Cretaceous Punt Sandstone Member, a massive deep-water clastic deposystem, Inner Moray Firth, UK North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Argent, J.D.; Stewart, S.A. [Amerada Hess Ltd., London (United Kingdom); Underhill, J.R. [University of Edinburgh (United Kingdom). Dept. of Geology and Geophysics

    2000-08-01

    Interpretation of high-quality seismic data, constrained by exploration wells, provides insights into controls on the stratigraphic architecture and deep-water sedimentary processes that governed deposition of the Lower Cretaceous Punt Sandstone Member in the Inner Moray Firth Basin. We suggest a model of deposition in which sediment provenance from the north and west progressively filled depositional accommodation in proximal depocentres before spilling into more distal areas via linear, confined and incised channel complexes. As well as giving important clues into post-rift depositional processes in the basin, and a well-imaged ancient analogue for the deposition of massive deep-water sands, the seismic and stratigraphic data may also provide important insights into factors governing the poorly imaged Lower Cretaceous sands in neighbouring basins of the North Sea. (Author)

  8. Study of Social and Cultural Characteristics of Drug Offenders in Ahwaz Municipal Areas Using Geographic Information System (GIS)

    OpenAIRE

    Somayyeh Fathtabar; Abdolrahim Asadollahi; Shiva Haji Azizi; Amin Arabpour; Ali Havasi

    2016-01-01

    Objective: This study examines the social and cultural structure of drug offenses in Ahwaz municipal areas using GIS. Method: The population of the study consisted of drug offenders in Correction and Rehabilitation Center of Ahwaz in 2013. Statistical tests and graphs, including Mean Center test, Standard Deviation Ellipse, Kernel Density Estimation were used in this study. Results: The most important centers of drug crime are in the same border with informal settlement areas, such as Kut Abd...

  9. Congenital malformations among live births at arvand hospital, ahwaz, iran - a prospective study

    International Nuclear Information System (INIS)

    The aim of the study was to determine the profile of congenital malformations (CM) among live births at Arvand hospital, in Ahwaz city. In this prospective study all of the neonates born at Arvand hospital in Ahwaz from 2004 to 2006 were registered. Stillbirths and those who died in a few hours after birth were excluded and finally 4660 newborns were enrolled. Of the 4660 live births 94 (20.2/1000) had at least a CM. The predominant systems involved were musculoskeletal (7.9/1000), followed by genitourinary (7.1/1000), central nervous (2.4 /1000), digestive (1.1/1000) and chromosomal anomalies (0.9/1000). Although the frequency of malformations in the study was approximately similar to other investigations, if we include abortions, stillbirths and if we used screening tests and genetic studies, this rate was more than 20.1/1000. (author)

  10. Study of Social and Cultural Characteristics of Drug Offenders in Ahwaz Municipal Areas Using Geographic Information System (GIS

    Directory of Open Access Journals (Sweden)

    Somayyeh Fathtabar

    2016-05-01

    Full Text Available Objective: This study examines the social and cultural structure of drug offenses in Ahwaz municipal areas using GIS. Method: The population of the study consisted of drug offenders in Correction and Rehabilitation Center of Ahwaz in 2013. Statistical tests and graphs, including Mean Center test, Standard Deviation Ellipse, Kernel Density Estimation were used in this study. Results: The most important centers of drug crime are in the same border with informal settlement areas, such as Kut Abdullah, Lashkar Abad, and Khashayar (urban areas 5 and 6 of Ahwaz city. In addition, there is a direct relationship between illiteracy rate & population density and crime rate. Discussion and Conclusion: Spatial analysis of geographic crime and punishment can act as a means for security and safety policy making in the fight against drugs.

  11. Facies analysis and sequence stratigraphy review of Ponta Grossa formation, Parana Basin - emphasis on the Tibagi Member sandstones; Analise de facies e revisao da estratigrafia de sequencias da Formacao Ponta Grossa, Bacia do Parana - enfase nos arenitos do Membro Tibagi

    Energy Technology Data Exchange (ETDEWEB)

    Candido, Ary Gustavo [PETROBRAS, Campos dos Goytacases, RJ (Brazil). Unidade de Negocio Exploracao e Producao da Bacia de Campos. Gerencia de Avaliacao de Blocos e Interpretacao Geologica e Geofisica]. E-mail: ary.candido@petrobras.com.br; Rostirolla, Sidnei Pires

    2006-11-15

    Lithostratigraphic studies of Ponta Grossa Formation (Devonian - Parana Basin) suggest the recognition of three members, denominated: Jaguariaiva Member, Tibagi Member and Sao Domingos Member. This work studies the formation as a whole, but predominantly the Tibagi Member, the most controversial, regarding its stratigraphic genesis. Differing from the other members, that are predominantly pelitic, the Tibagi Member has a sandy composition with the facies; distal storm, proximal storm, deltaic outlet bars and littoral drift currents. The disposition of these facies, formed in marine transitional environment, reveals deposition with a pro gradational array, beginning in shallow platformal environment, with strong storm influence, and covered by deltaic outlet bar deposits. Finally, the coastal drift currents process prevailed. Based on the facies analysis and the comparison between gamma-ray profiles of outcrops and geophysical profiles of wells, the formation was divided in two depositional sequences. In the upper sequence, where it is suggested that Tibagi Member sandstones represent deposits formed in a tract similar to a shelf edge systems tract. This system tract was used (elaborated for passive margin basins, and not for ramp type basins, as the Parana Basin), to have the possibility of obtaining good explanations to understand the deltaic progradation associated with the deposition of that interval, clarifying issues referring to the relative sea level behavior, to the sedimentary contribution, and to the stratigraphic pile up. Finally, comparisons were made with existing stratigraphic models, with the aim to establish a discussion on this important subject in order to promote new debate on the Ponta Grossa Formation stratigraphic sequences. (author)

  12. Etiology of Hirsutism in Women Referring to Endocrinology Clinic in Ahwaz

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    Hajieh Shahbazian

    2013-04-01

    Full Text Available Background: This study is carried out aiming to determine the prevalence of various causes of hirsutism in patients referred to the endocrine clinic of Golestan Hospital in Ahwaz. Materials and Methods: In a cross-sectional study, 520 patients suffered from hirsutism whiting the age range of 10-50 year old participated based on Ferriman-Gallwey hirsutism classification system.Results: Out of 520 patients under study, 274 ones (52.7% had PCO, 176 ones (33.8% suffered from idiopathic hirsutism, 24 persons (4.6% had hyperprolactinemia, 22 persons (4.2% had hirsutism caused by drugs consumption, 11 ones (2.1% had hypothyroidism, 9 patients (1.7% had cushing as well as 3 persons (0.57% having Late Onset Congenital Adrenal Hyperplasia (LOCAH and 1 person (0.19% had ovarian tumor. Conclusion: Results of this study show that PCO and idiopathic hirsutism constitute totally 86% of hirsutism causes.

  13. Studying Consumers Conformity in Virtual Networks between the Students of Shahid Chamran University of Ahwaz

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    Bahram Ranjbarian

    2013-01-01

    Full Text Available Nowadays, buying behavior and consumers’ communication behavior have been influencedby social networks. Consumers will be motivated to use information regarding goods orservices purchase and their buying behavior will be shaped. Such networks lead to theformation of virtual communities that move groups and people toward conformity. In thisresearch, consumer internet conformity (normative and informational conformities has beeninvestigated. The study sample included 384 students of Shahid Chamran University ofAhwaz. For data analysis SPSS 16 and LISREL 8.5 softwares were used. The results indicatethat the sense of belongingness and community expertise on community trustworthiness andcommunity trustworthiness on informational consumer conformity have positive andsignificant impact. Also self esteem has no significant effect on conformity motivation.However, the variables of involvement on conformity motivation and conformity motivationon normative consumer conformity have positive and significant impact.

  14. Urban Lifestyle and Social Participation of Aged Citizens of Ahwaz City: A Regional Survey

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    Abdolrahim Asadollahi

    2013-07-01

    have led social scientists to think about deterrents of social participation (SP and other declining factors. At the moment, severe decrease in SP amongst the increasing population of elderly is assumed to be happening because of injustice and social inequality. Iran and our research community in particular - Khuzestan province and Ahwaz city- is a multi-ethnic society, where the resources of community and society should be distributed in a justified and equal manner. Every study in its policies should attend to this issue and special groups specifically in cases involving CE and SWB. Elderly, women, ethnic groups, and enhancing their well-being and the situation of social problems are areas that require further attention. This study looks forward to understanding the reasons for such neglected interest in these areas and hope to share a new vision for policy making at micro level for aged citizens of Ahwaz city. An attempt is made to investigate the role of variables such as social participation and background characteristics in urban lifestyle of the aged in the hope of ensuring a better health and an acceptable end-life condition for them.     Materials & Methods   Research population in this survey includes the elderly of Ahwaz, who were 60 years old and above. During 1997 to 2007, Ahwaz showed a higher ratio of aged citizens among all cities of Khuzestan province (3.1% in total aged population of the province. All data were based on KSCC and ISCC annual reports in 2007 (KSCC, 2007. The study has evaluated the factors of SP. Theories of participation, social capital and trust, and inequality were reviewed. Consequently, six factors were considered. Regarding the last census in 2007, total population of Ahwaz city was 969,843 inhabitants, of whom 51594 were aged 60 and above (male: 26,294 and female: 25,345. Unfortunately, in the national and provincial reports on population and census, there is no independent data for ethnicity. Research sample was obtained

  15. Upper Jurassic - Lower Cretaceous turbidite sandstones in the Central Graben, North Sea; with special focus on the Danish Gertrud Graben

    Energy Technology Data Exchange (ETDEWEB)

    Johannessen, P.

    1998-10-01

    Thick Late Jurassic - Early cretaceous turbidite sandstone successions in the Central Graben are uncommon except from the Moray Firth and Viking Graven north of the Central Graben, where several important hydrocarbon producing turbidite sandstone fields are known. The only hydrocarbon producing turbidite reservoir sandstones in the Central Graben is the up to 55 m thick Ribble Sandstone Member located in the British South-west Central Graben, where it is lying above thick shoreface reservoir sandstones of the Fulmar Formation, separated by offshore claystones of the Kimmeridge Clay Formation. The turbidite sandstones of the Ribble Sandstone Member derived from the more proximal thick reservoir sandstones of the Fulmar Formation located near the Mid North Sea High. It has not yet been possible to correlate thick shoreface sandstones of the Norwegian Ula Formation or the Danish Heno Formation to more distal thick turbidite sandstones derived from the shoreface sandstones. (au) 60 fig., 85 refs.

  16. The Effects of Attribution Retraining on Optimism and Pessimism of Elementary School Students in Ahwaz, Iran

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    Kh Ramezani

    2015-05-01

    Full Text Available Background & aim: Optimism, due to its impact on mental and physical health, is of utmost importance. Finding practical and scientific methods to increase optimism and alleviate pessimism are essential. The purpose of the present study was to identify the effect of attribution retraining on optimism, and pessimism of female six-grade elementary students in Ahwaz primary schools, Iran. The attribution retraining was considered as independent variable and optimism and pessimism were considered as dependent variables. Methods: In the present experimental study, 54 sixth-grade primary school students were randomly selected and then divided to two groups of experiment and control groups. The present study was a field experimental research, including pretest-posttest and control group. The research instrument was the Children's Attribution Styles Questionnaire (CASQ and was presented by Seligman, translated by ShehniYailagh and Ramezani, and adapted to Iranian students’ Culture. . Before starting the retraining, two groups were tested in pre-tests of optimism, pessimism and then, the experiment group was taught attribution retraining, and the control group nothing. At the end of the training course, two groups were tested in post-tests of optimism and pessimism. Results: Results showed that attribution retraining (as independent variables, had a great effect on the dependent variables. The results showed that attribution retraining had increased the meaningful (p= 0/001 amount of optimism and it had decreased pessimism (p = 0/001 significantly. Conclusion: Attribution retraining with increased optimism and pessimism can prevent and reduce the mental and physical health.

  17. Prevalence of Musculoskeletal Disorders among Paramedics Working in a Large Hospital in Ahwaz, Southwestern Iran in 2010

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    KR Shafizadeh

    2011-06-01

    Full Text Available Background:Musculoskeletal disorders (MSDs are common among employees throughout the world, particularly in high risk groups such as nurses.Objective: To determine the prevalence of MSDs among nurses in a large hospital in Ahwaz, southwestern Iran, and to examine its correlation with gender, age, shift working, years at service and smoking.Methods: Using a self-reported questionnaire-based cross-sectional study, Nordic questionnaire for MSDs was disseminated to all inpatient hospital paramedics (n=195 in a large hospital in Ahwaz.Results: Questionnaires of 161 participants were completed and returned back for analysis (response rate of 83%. The reported prevalence of MSDs was very high in the studied paramedics so that more than 90% of them reported at least one MSD in last week. The most prevalent site affected was that of neck (64% followed by head (62.1%, knees (54.7% and wrists/hands (49.7%; the least frequent disorder was that of elbows (14.3%. MSD was more common in females and increased with age and years of service. Non-shift workers reported more neck and elbows MSDs than shift workers.Conclusion: Considering the very high prevalence of MSDs among paramedics, it is suggested that they engage in an exercise program at their work place to lower the risk of MSDs and promote working efficiency.

  18. Kaolinite Mobilisation in Sandstone

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Fabricius, Ida Lykke; Kets, Frans

    2013-01-01

    The effect of temperature and salinity on sandstone permeability is critical to the feasibility of heat storage in geothermal aquifers. Permeability reduction has been observed in Berea sandstone when the salinity of the pore water is reduced as well as when the sample is heated. Several authors...

  19. Isolation of Pathogenic Bacteria on the House Fly, Musca domestica L. (Diptera:Muscidae), Body Surface in Ahwaz Hospitals, Southwestern Iran

    Institute of Scientific and Technical Information of China (English)

    Hamid Kassiri; Kamran Akbarzadeh; Anvar Ghaderi

    2012-01-01

    Objective: There is abundant opportunity for house fly, Musca domestica, to become contaminated and, in turn, to contaminate the patient environment. This study has been conducted with the aim of isolating and identifying the probable pathogenic inoculations of the flies in three hospitals in Ahwaz County, Khuzestan province, south-west of Iran. Methods: Adult flies were collected by means of insect net and then transferrs to lab for microbiological process.Results:Totally on all house fly samples the bacteria genus Pseudomonas and Esherichia coli had the significantly highest rate of infection (P<0.05). The genera Klebsiella, Bacillus, and Diphtroid has significant lowest rate of infection. Hot and humid weather of the Khuzestan province which is host of patients coming from far localities for hospitalization, provide suitable conditions for housefly activities during the year. Conclusions: Thus suitable and applicable control methods such as environmental sanitations should be implemented for hospital environment in Ahwaz County.

  20. Stochastic reconstruction of sandstones

    Science.gov (United States)

    Manwart; Torquato; Hilfer

    2000-07-01

    A simulated annealing algorithm is employed to generate a stochastic model for a Berea sandstone and a Fontainebleau sandstone, with each a prescribed two-point probability function, lineal-path function, and "pore size" distribution function, respectively. We find that the temperature decrease of the annealing has to be rather quick to yield isotropic and percolating configurations. A comparison of simple morphological quantities indicates good agreement between the reconstructions and the original sandstones. Also, the mean survival time of a random walker in the pore space is reproduced with good accuracy. However, a more detailed investigation by means of local porosity theory shows that there may be significant differences of the geometrical connectivity between the reconstructed and the experimental samples.

  1. Detection and Typing of Human Papilloma Virus DNA by PCR in Head and Neck Squamous Cell Carcinoma in E.N.T. Ward of Ahwaz Imam Hospital

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    S. Nikakhlagh

    2008-07-01

    Full Text Available Introduction & Objective: Nowadays, epidemiological and experimental evidences in western countries consistently support an etiological role for human papillomavirus (HPV in head and neck squamous cell carcinoma (SCC. The role of HPV in the etiology of head and neck SCC in developing countries such as Iran has not been investigated. The purpose of the present study was to investigate HPV DNA in the head and neck cancer by polymerase chain reaction (PCR in patients referred to Imam Khomeini Hospital Ahwaz.Materials & Methods: In this prospective cross sectional study 176 patients with SCC of head and neck who admitted in Ahwaz Imam Khomeini Hospital were evaluated with PCR for HPV DNA and compared to 176 control samples with benign pathology. Results: In this study 7 specimens (3.97% of the case group were positive for HPV DNA that include HPV 16(3 cases ,18(2 cases ,57(1 case, 33 (1case and only 1 specimen (0.57% of the control group was positive that include HPV 6 ( P value<0.001Conclusion: This study demonstrates the presence of HPVs in the SCC of head and neck. Further studies are needed to evaluate larger population in Ahwaz for the presence and types of HPV.

  2. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    World-class sandstone-type uranium deposits are defined as epigenetic concentrations of uranium minerals occurring as uneven impregnations and minor massive replacements primarily in fluvial, lacustrine, and deltaic sandstone formations. The main purpose of this introductory paper is to define, classify, and introduce to the general geologic setting for sandstone-type uranium deposits

  3. Basic investigation on promotion of joint implementation in fiscal 2000. Energy conservation measure project for Ahwaz Steel Complex in Iran; 2000 nendo kyodo jisshi nado suishin kiso chosa hokokusho. Iran Ahwaz seitetsusho ni okeru sho energy taisaku jigyo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    With an objective to save energy and reduce greenhouse gas emission, a project has been discussed to introduce a gas turbine combined cycle power generation system for effective waste heat utilization and a pellet coating facility into the direct reduction steel making plant of Ahwaz Steel Complex in the Islamic Republic of Iran. The project will have a waste heat boiler installed at the outlet of the MIDREX plant waste heat recovery device to link it with a gas turbine combined cycle power plant to structure a 42-MW power generation system. In addition, productivity enhancement was attempted by applying the raw material pellets with coating to raise the reduction gas blow-in temperature. The energy saving effect expected from this project would be saving of 63,140 tons of crude oil equivalent annually, and the greenhouse effect gas reducing effect would reduce 173,790 t-CO2 annually. Although the investment will require about 3.16 billion yen, the cost reduction amount in association with power generation is small because of the power purchase unit cost being as very low as 1.9 yen/kWh, making the investment recovery period 10.2 years. Therefore, the project will not be realizable economically. (NEDO)

  4. Foraging population and territory estimates for Microcerotermes diversus (Isoptera: Termitidae) through mark-release-recapture in Ahwaz (Khouzestan, Iran).

    Science.gov (United States)

    Habibpour, B; Ekhtelat, M; Khocheili, F; Mossadegh, M S

    2010-12-01

    Microcerotermes diversus Silvestri (Isoptera: Termitidae), an important pest in Ahwaz (Khouzestan, Iran), causes serious economic damage to wooden products in buildings. In this study, we determined the foraging populations and territories of this species using mark-release-recapture techniques. Based on both the weighted mean model and Lincoln index methods, mean termite foraging population estimates for two colonies, A and B, were 2,984,489 +/- 258,802 and 326,134 +/- 8,713, respectively. Estimates with the Lincoln index were 2,731,229 +/- 813,081 for colony A and 321,493 +/- 138,499 for colony B. Estimated horizontal foraging territories for colonies A and B were 25.59 and 44.16 m2, respectively. The maximum and minimum linear foraging distances were 5.40 and 2.14 m for colony A and 9.14 and 1.86 m for colony B, respectively. Our data expand the knowledge about the biology, ecology and behavior of M. diversus.

  5. The Upper Cretaceous Ostravice Sandstone in the Polish sector of the Silesian Nappe, Outer Western Carpathians

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    Cieszkowski Marek

    2016-04-01

    Full Text Available The Ostravice Sandstone Member was identified and described as a lithostratigraphic unit in the Polish part of the Outer Carpathians. This division occurs in the lowermost part of the Godula Formation, is underlain by variegated deposits of the Mazák Formation or directly by the Barnasiówka and Lhoty formations, and overlain by the Czernichów Member of the Godula Formation. Domination by thick- and very thick-bedded sandstones, conglomeratic sandstones and conglomerates rich in calcareous clasts, mostly of the Štramberk-type limestones, is typical for the Ostravice Sandstone Member. These deposits are widespread between the Moravskoslezské Beskydy Mountains in the Czech Republic and the Ciężkowice Foothills in Poland. The documentation of the Ostravice Sandstone Member occurrence as well as the petrological, sedimentological features, and inventory of the carbonate clasts are presented here.

  6. Provenance of the Lower Triassic Bunter Sandstone Formation

    DEFF Research Database (Denmark)

    Olivarius, Mette; Weibel, Rikke; Friis, Henrik;

    2016-01-01

    Zircon U–Pb geochronometry, heavy mineral analyses and conventional seismic reflection data were used to interpret the provenance of the Lower Triassic Bunter Sandstone Formation. The succession was sampled in five Danish wells in the northern part of the North German Basin. The results show...... Shield did not supply much sediment to the basin as opposed to what was previously believed. Sediment from the Variscan belt was transported by wind activity across the North German Basin when it was dried out during deposition of the aeolian part of the Volpriehausen Member (lower Bunter Sandstone......). Fluvial sand was supplied from the Ringkøbing-Fyn High to the basin during precipitation events which occurred most frequently when the Solling Member was deposited (upper Bunter Sandstone). Late Neoproterozoic to Carboniferous zircon ages predominate in the Volpriehausen Member where the dominant age...

  7. Diagenetic evolution and its effect on reservoir-quality of fan delta sandstones during progressive burial:Evidence from the upper part of the fourth member of Shahejie formation, Bonan sag, Jiyang depression

    Institute of Scientific and Technical Information of China (English)

    马奔奔; 张少敏; 操应长; 贾艳聪; 王艳忠

    2015-01-01

    Petrographic analysis combined with various techniques, such as thin section identification, fluid inclusions, isotopic data, petro-physical property testing and oil testing results, was used to study diagenetic evolution and its effect on reservoir-quality of fan delta reservoirs of Es4s in the Bonan sag. The diagenesis is principally characterized by strong compaction, undercompaction, multi-phase of dissolution and cementation. Compaction played a more important role than cementation in destroying the primary porosity of the sandstones. The reservoirs have experienced complicated diagenetic environment evolution of “weak alkaline− acid−alkalinity−acid−weak alkalinity” and two-stage of hydrocarbon filling. The diagenetic sequences are summarized as “early compaction/early pyrite/gypsum/calcite/dolomite cementation→feldspar dissolution/the first stage of quartz overgrowth→ early hydrocarbon filling→quartz dissolution/anhydrite/Fe-carbonate cementation→Fe-carbonate dissolution/feldspar dissolution/ the second stage of quartz overgrowth→later hydrocarbon filling→later pyrite cementation. In the same diagenetic context, the diagenetic evolution processes that occurred in different sub/micro-facies during progressive burial have resulted in heterogeneous reservoir properties and oiliness. The braided channel reservoirs in fan delta plain are poorly sorted with high matrix contents. The physical properties decrease continually due to the principally strong compaction and weak dissolution. The present properties of braided channel reservoirs are extremely poor, which is evidenced by few oil layers developed in relatively shallow strata while dry layers entirely in deep. The reservoirs both in the underwater distributary channels and mouth bars are well sorted and have a strong ability to resist compaction. Abundant pores are developed in medium-deep strata because of modifications by two-stage of acidic dissolution and hydrocarbon filling. The

  8. 徐家围子断陷登娄库组三段成岩模拟与致密砂岩储层类型预测%Diagenetic numerical modeling and tight sandstone reservoir types prediction of the Member 3 of the Denglouku Formation of the Xujiaweizi Fault Depression

    Institute of Scientific and Technical Information of China (English)

    程仲平; 孟元林; 田伟志; 孟凡晋; 王建伟; 徐赫; 潘雪梅; 王维安; 蒋学峰

    2011-01-01

    为了预测松辽盆地徐家围子断陷深层登娄库组三段致密砂岩储层的类型和质量,根据深层的勘探实践和储层分析化验资料,将碎屑岩的成岩作用进一步细化为早成岩阶段A期、B期,中成岩阶段A1亚期,A2亚期、B1亚期、B2亚期,晚成岩阶段A期和B期3个阶段8个(亚)期,其中处于晚成岩阶段A期和B期的致密砂岩储层已不能产出工业气流。孔隙度和渗透率的统计结果表明,徐家围子断陷致密砂岩储层的物性主要受沉积相和成岩作用的影响,不同的沉积相和成岩相组合形成了致密砂岩3种类型的储层(Ⅱ、Ⅲ、Ⅳ类)。通过模拟古地温、镜质组反射率、甾烷异构化、粘土矿物转化和自生石英含量随时间的变化规律,模拟了成岩演化史、预测了成岩阶段和成岩相的平面分布。综合考虑沉积相和成岩作用对储层物性的影响,应用成岩作用数值模拟技术,通过成岩相分析,结合沉积相的研究成果,预测了登三段致密砂岩各种类型储层的平面分布特征。目前已发现的工业气流井主要位于Ⅱ、Ⅲ类储层分布的范围内。Ⅳ类储层中未发现工业气流,该类致密砂岩储层主要分布在晚成岩阶段A期—B期或处于滨浅湖相。引起成岩作用差异的主要因素是埋深。%To predict the reservoir type and quality of the tight sandstones of the Member 3 of the Denglouku Formation in the deep horizons of the Xujiaweizi Fault Depression,Songliao Basin,the diageneses of clastic rocks are divided into the period A of early diagenetic stage,the period B of early diagenetic stage,the sub-period A1 of middle diagenetic stage,the sub-period A2 of middle diagenetic stage,the sub-period B1 of middle diagenetic stage,the sub-period B2 of middle diagenetic stage,the period A of late diagenetic stage and the period B of late diagenetic stage on the base of the exploration results of the deep horizons and the reservoir

  9. Composition and Provenance of Sandstones and Siltstones in Paleogene, Huimin Depression, Bohai Bay Basin, Eastern China

    Institute of Scientific and Technical Information of China (English)

    Zhang Jinliang; Zhang Xin

    2008-01-01

    This study was conducted to distinguish the compositions and provenance of sandstones and siltstones in the Ek1-Es3 members of Huimin (惠民) depression. The samples have been analyzed for petrographic, major element and selected trace element compositions (including REE). The results show that the sandstones from the first member of Kongdian (孔店) Formation (Ek1) have higher quartz compositions than those from the fourth member (Es4) and the third member (Es3) of Shahejie (沙河街) Formation. The alkali feldspar/plagioclase ratio in the A-CN-K diagrams decreases in the order Ek1>Es4>Es3, which suggests that the Ek1 member had a more alkali feldspar-rich granitoid source and more intense weathering of the source than the Es4 and Es3 members. The mineral distributions in the A-CN-K diagrams also indicate that the sandstones and slltstones in the three members underwent K-metasomatism. Extrapolation of the sandstones and siltstones back to the plaginclase-alkali feldspar line in the A-CN-K diagram suggests a high average plagioclase to alkali feldspar ratio in the provenance (tonalite to granite). In addition, the chemical index of weathering (CIW) and chemical index of alteration (CIA) parameters of the sandstones and siltstones suggest that the weathering of the first cycle material was intense, and the CIW decreases in the order Ek1>Es4>Es3. Trace element ratios suggest all the sedimentary rocks were mostly derived from granitoids. Elemental ratio plots (e.g., Th/Sc vs. Eu/Eu*) of sandstones and siltstones suggest a mix of a granodiorite-tonalite source as a source of the sandstones and siltstones. The sandstones and siltstones of Es3 and Es4 members also contain higher Eu/Eu* and lower Th/Sc ratios than the sandstones and siltstones of Ek1 member. As is consistent with the petrography, it suggests that the sandstones and siltstones of Es3 and Es4 members are derived from a source with less granite and more granodiorite-tonalite than the sandstones and

  10. Analysis of land suitability for urban development in Ahwaz County in southwestern Iran using fuzzy logic and analytic network process (ANP).

    Science.gov (United States)

    Malmir, Maryam; Zarkesh, Mir Masoud Kheirkhah; Monavari, Seyed Masoud; Jozi, Seyed Ali; Sharifi, Esmail

    2016-08-01

    The ever-increasing development of cities due to population growth and migration has led to unplanned constructions and great changes in urban spatial structure, especially the physical development of cities in unsuitable places, which requires conscious guidance and fundamental organization. It is therefore necessary to identify suitable sites for future development of cities and prevent urban sprawl as one of the main concerns of urban managers and planners. In this study, to determine the suitable sites for urban development in the county of Ahwaz, the effective biophysical and socioeconomic criteria (including 27 sub-criteria) were initially determined based on literature review and interviews with certified experts. In the next step, a database of criteria and sub-criteria was prepared. Standardization of values and unification of scales in map layers were done using fuzzy logic. The criteria and sub-criteria were weighted by analytic network process (ANP) in the Super Decision software. Next, the map layers were overlaid using weighted linear combination (WLC) in the GIS software. According to the research findings, the final land suitability map was prepared with five suitability classes of very high (5.86 %), high (31.93 %), medium (38.61 %), low (17.65 %), and very low (5.95 %). Also, in terms of spatial distribution, suitable lands for urban development are mainly located in the central and southern parts of the Ahwaz County. It is expected that integration of fuzzy logic and ANP model will provide a better decision support tool compared with other models. The developed model can also be used in the land suitability analysis of other cities. PMID:27376847

  11. Analysis of land suitability for urban development in Ahwaz County in southwestern Iran using fuzzy logic and analytic network process (ANP).

    Science.gov (United States)

    Malmir, Maryam; Zarkesh, Mir Masoud Kheirkhah; Monavari, Seyed Masoud; Jozi, Seyed Ali; Sharifi, Esmail

    2016-08-01

    The ever-increasing development of cities due to population growth and migration has led to unplanned constructions and great changes in urban spatial structure, especially the physical development of cities in unsuitable places, which requires conscious guidance and fundamental organization. It is therefore necessary to identify suitable sites for future development of cities and prevent urban sprawl as one of the main concerns of urban managers and planners. In this study, to determine the suitable sites for urban development in the county of Ahwaz, the effective biophysical and socioeconomic criteria (including 27 sub-criteria) were initially determined based on literature review and interviews with certified experts. In the next step, a database of criteria and sub-criteria was prepared. Standardization of values and unification of scales in map layers were done using fuzzy logic. The criteria and sub-criteria were weighted by analytic network process (ANP) in the Super Decision software. Next, the map layers were overlaid using weighted linear combination (WLC) in the GIS software. According to the research findings, the final land suitability map was prepared with five suitability classes of very high (5.86 %), high (31.93 %), medium (38.61 %), low (17.65 %), and very low (5.95 %). Also, in terms of spatial distribution, suitable lands for urban development are mainly located in the central and southern parts of the Ahwaz County. It is expected that integration of fuzzy logic and ANP model will provide a better decision support tool compared with other models. The developed model can also be used in the land suitability analysis of other cities.

  12. A New Classification of Sandstone.

    Science.gov (United States)

    Brewer, Roger Clay; And Others

    1990-01-01

    Introduced is a sandstone classification scheme intended for use with thin-sections and hand specimens. Detailed is a step-by-step classification scheme. A graphic presentation of the scheme is presented. This method is compared with other existing schemes. (CW)

  13. Laser cleaning of Rakowicze sandstone

    OpenAIRE

    Nijland, T.G.; Wijffels, T.J.

    2003-01-01

    Decisions about the cleaning of natural stone should always be made within the awareness of direct and indirect damage that may be the result of cleaning. During the last decade, laser cleaning of objects and monuments of natural stone has become increasingly popular. Whereas a considerable amount of literature has been devoted to the effect of laser cleaning on marble and limestone, research into the effects on sandstone is limited. In the present paper, the effect of two cleaning methods, v...

  14. Evaluation of serum levels in T3, T4 and TSH in beta-thalassemic patients referred to the Abuzar hospital in Ahwaz

    Science.gov (United States)

    Asad, Zari Tahannejad; Ghazanfari, Majid; Naleini, Seyyed Nima; Sabagh, Azam; Kooti, Wesam

    2016-01-01

    Introduction Regarding the functioning of the endocrine system, and especially in the thyroid of patients with thalassemia, multiple studies in different parts of the world have reported conflicting results. The aim of this study was to assess the levels of thyroid hormones and TSH in beta-thalassemic patients in the city of Ahwaz. Methods In this matched case-control study, 105 patients in the case group and 105 subjects as controls were randomly selected from clients referred to the Abuzar hospital in 2015–2016. Serum levels of T3, T4, and TSH hormones were measured using ELISA. Data was processed with the SPSS15 software and tested by using independent t-tests and logistic regression. Results The study results showed that the serum level of T3 hormone did not significantly differ between the two groups (p> 0.05). Whereas the serum level of T4 was lower in the case group, compared to the controls, which was statistically significant (p hemochromatosis in patients with thalassemia major due to the effect of accumulation of iron on thyroid function and detection of hypothyroidism. This course of action will prevent incidence of this complication in patients with thalassemia major. PMID:27648188

  15. The geometry and lithology of the Cima Sandstone Lentil: a paleoseep-bearing interbed in the Moreno Formation, central California

    Science.gov (United States)

    Wheatley, P. V.; Schwartz, H.

    2007-12-01

    The Cima Sandstone Lentil outcrops over a relatively small area on the western side of the San Joaquin Valley in central California. Here this unit can be found in the Panoche Hills in the northern portion of the field area and the Tumey Hills in the southern portion of the field area. The Cima Sandstone resides within the 800m Moreno Formation that spans the Maastrichtian to the Danian. The Moreno Formation comprises four members, which are the Dosados Member, the Tierra Loma Member, the Marca Shale Member, and the Dos Palos Shale Member (of which the Cima Sandstone is an interbed). The Cima Sandstone contains numerous large carbonate mounds, concretions, and pavements, indicating paleoseep activity. The Cima Sandstone has never been studied in detail, but recent interest in sandstone injectites as well as interest in paleoseeps has prompted us to examine this interbed more carefully. The Cima is an immature sandstone composed primarily of quartz along with small amounts of micas and feldspars as well as varying amounts of glauconite. These minerals are generally cemented by carbonate but, occasionally, iron oxide cement is present locally. Much variation exists within the Cima Sandstone Lentil and we seek to characterize and understand this variation. One of the most obvious sources of variability is the thickness of the unit itself. The thickness ranges from near 60m in the northern Panoche Hills to only 9m in the Tumey Hills. Induration also varies noticeably, from well cemented in the north, to unconsolidated in the south. Similarly, the sandstone is grain-supported and houses some depositional structures in the northern outcrops but becomes largely matrix-supported and lacking bedding in the southern outcrops. Preliminary data suggests that proximity to carbonate concretions, fluid conduits, and underlying injectites may have some influence over grain size and sorting.

  16. Black weathering of Bentheim and Obernkirchen sandstone

    NARCIS (Netherlands)

    Nijland, T.G.; Dubelaar, C.W.; Hees, R.P.J. van; Linden, T.J.M. van der

    2003-01-01

    Black weathering of sandstone in monuments is widespread. Some obiects owe their name to it, like the Porta Nigra in Triet (Germany). Other than the black gypsum crusts common on limestone, the black weathering layer on sandstone is rather thin and well adhe¡ent. Formation of such layers on Bentheim

  17. Genesis and identification of high gamma sandstone in the first member of Nantun formation of Wunan depression in Hailar Basin%海拉尔盆地乌南凹陷南一段高伽马砂岩成因与识别

    Institute of Scientific and Technical Information of China (English)

    于振锋; 程日辉; 赵小青; 孙凤贤; 许中杰; 沈艳杰

    2012-01-01

    In order to improve the accuracy of logging lithology identification of high natural gamma sandstone in Wunan depression in Hailar Basin, in terms of rock core and microscopic sections description and logging analysis, the causes and i-dentifieation of high gamma sandstones were discussed. The classification of the sandstone CNL values can provide a estimating under a certain porosity degree. The high natural gamma sandstones can be identified using deep lateral resistivity ( DLL), micro lateral resistivity logging ( RMLL) , DEN and AC. The research results show that the factors affecting these sandstones with high natural gamma are tuffaceous matter, clay, oil, feldspar and calcium. High natural gamma sandstones express high content of thorium or uranium from logging data. The tuffaceous matter leads to the enrichment of thorium, clay leads to the enrichment of uranium, thorium and potassium, oil leads to the enrichment of uranium, feldspar leads to the enrichment of potassium, and calcareous matter leads to the decrease of uranium content. The affecting factors of sandstone nature gamma ray are high tuffaceous matter, high feldspar and high clay ranging from edge to center of the depression.%为了提高海托尔盆地乌南凹陷高伽马砂岩测井岩性解释的准确性,采用岩心观察、显微镜下描述和测井曲线分析相结合的方法对高伽马砂岩的成因和识别方法进行探讨.对砂岩的补偿中子值进行分类以排除孔隙度对测井曲线的影响,再利用深侧向电阻率、微侧向电阻率和补偿密度交会识别高自然伽马砂岩.研究结果表明:影响砂岩自然伽马特征的因素有凝灰质、黏土、油、长石以及钙质;高自然伽马砂岩具有高钍或者高铀含量的特征;凝灰质导致钍富集,黏士导致铀、针和钾均富集,油导致铀富集,长石导致钾富集,钙质导致铀含量降低;从凹陷边缘至凹陷中央影响砂岩高自然伽马因素依次为高凝灰质含

  18. National uranium resource evaluation. Geology and recognition criteria for sandstone uranium deposits of the salt wash type, Colorado Plateau Province. Final report

    International Nuclear Information System (INIS)

    The uranium-vanadium deposits of the Salt Wash Member of the Morrison Formation in the Colorado Plateau are similar to sandstone uranium deposits elsewhere in the USA. The differences between Salt Wash deposits and other sandstone uranium deposits are also significant. The Salt Wash deposits are unique among sandstone deposits in that they are dominantly vanadium deposits with accessory uranium. The Salt Wash ores generally occur entirely within reduced sandstone, without adjacent tongues of oxidized sandstone. They are more like the deposits of Grants, which similarly occur in reduced sandstones. Recent studies of the Grants deposits have identified alteration assemblages which are asymmetrically distributed about the deposits and provide a basis for a genetic model for those deposits. The alteration types recognized by Shawe in the Slick Rock district may provide similar constraints on ore formation when expanded to broader areas and more complete chemical analyses

  19. National uranium resource evaluation. Geology and recognition criteria for sandstone uranium deposits of the salt wash type, Colorado Plateau Province. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Thamm, J.K.; Kovschak, A.A. Jr.; Adams, S.S.

    1981-01-01

    The uranium-vanadium deposits of the Salt Wash Member of the Morrison Formation in the Colorado Plateau are similar to sandstone uranium deposits elsewhere in the USA. The differences between Salt Wash deposits and other sandstone uranium deposits are also significant. The Salt Wash deposits are unique among sandstone deposits in that they are dominantly vanadium deposits with accessory uranium. The Salt Wash ores generally occur entirely within reduced sandstone, without adjacent tongues of oxidized sandstone. They are more like the deposits of Grants, which similarly occur in reduced sandstones. Recent studies of the Grants deposits have identified alteration assemblages which are asymmetrically distributed about the deposits and provide a basis for a genetic model for those deposits. The alteration types recognized by Shawe in the Slick Rock district may provide similar constraints on ore formation when expanded to broader areas and more complete chemical analyses.

  20. Experimental strain analysis of Clarens Sandstone colonised by endolithic lichens

    Directory of Open Access Journals (Sweden)

    D. Wessels

    1995-09-01

    Full Text Available Endolithic lichens occur commonly on Clarens Sandstone in South Africa, where they significantly contribute to the weathering of sandstone by means of mechanical and chemical weathering processes. This preliminary investigation reports on the success- ful use of strain gauges in detecting strain differences between sandstone without epilithic lichens and sandstone colonised by the euendolithic lichen Lecidea aff. sarcogynoides Korb. Mechanical weathering, expressed as strain changes, in Clarens Sandstone was studied during the transition from relatively dry winter to wet summer conditions. Daily weathering of sandstone due to thermal expansion and contraction of colonised and uncolonised sandstone could be shown. Our results show that liquid water in sandstone enhances the mechanical weathering of uncolonised Clarens Sandstone while water in the gaseous phase enhances mechanical weathering of sandstone by euendolithic lichens.

  1. "Sydney sandstone": Heritage Stone from Australia

    Science.gov (United States)

    Cooper, Barry; Kramar, Sabina

    2014-05-01

    Sydney is Australia's oldest city being founded in 1788. The city was fortunate to be established on an extensive and a relatively undeformed layer of lithified quartz sandstone of Triassic age that has proved to be an ideal building stone. The stone has been long identified by geologists as the Hawkesbury Sandstone. On the other hand the term "Sydney sandstone" has also been widely used over a long period, even to the extent of being utilised as the title of published books, so its formal designation as a heritage stone will immediately formalise this term. The oldest international usage is believed to be its use in the construction of the Stone Store at Kerikeri, New Zealand (1832-1836). In the late 19th century, public buildings such as hospitals, court houses as well as the prominent Sydney Town Hall, Sydney General Post Office, Art Gallery of New South Wales, State Library of New South Wales as well as numerous schools, churches, office building buildings, University, hotels, houses, retaining walls were all constructed using Sydney sandstone. Innumerable sculptures utilising the gold-coloured stone also embellished the city ranging from decorative friezes and capitals on building to significant monuments. Also in the late 19th and early 20th century, Sydney sandstone was used for major construction in most other major Australian cities especially Melbourne, Adelaide and Brisbane to the extent that complaints were expressed that suitable local stone materials were being neglected. Quarrying of Sydney sandstone continues today. In 2000 it was recorded noted that there were 33 significant operating Sydney sandstone quarries including aggregate and dimension stone operations. In addition sandstone continues to be sourced today from construction sites across the city area. Today major dimension stone producers (eg Gosford Quarries) sell Sydney sandstone not only into the Sydney market but also on national and international markets as cladding and paving products

  2. Effect of temperature on sandstone permeability

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Kjøller, Claus

    Hot water injection in geothermal sandstone aquifers is considered for seasonal energy storage in Denmark. However, an increase in the aquifer temperature might reduce permeability, and thereby increase production costs. An understanding of the factors that control permeability is required in order...... interaction forces. Quantitative analysis of images, in which mineralogy was mapped based on backscatter electron intensity in combination with energy dispersive X-ray analysis by using the QEMSCAN® system, was used to compare a tested sample to an untested Berea sandstone sample. During the experiment...

  3. A NMR characterisation of a banded sandstone.

    Science.gov (United States)

    Bolam, A C; Packer, K J

    1998-01-01

    1H-nuclear magnetic resonance (NMR) measurements have been carried out on a banded sandstone to investigate the effects of structural inhomogeneities on the fluid dynamics of the sample as a whole. The results obtained from average propagator measurements (the probability of a displacement z in a time delta or P delta (z)) using pulsed-field-gradient techniques have been compared to those obtained from a study of a homogeneous sandstone. Relaxation has been used to derive the pore sizes for the differing bands and have been found to correlate with flow velocities within the bands.

  4. Characteristics and controlling factors of movable fluid in deep-buried high-pressure and low-permeability sandstone reservoirs:A case study of middle section of 3rd member of Shahejie Formation in Wendong Oil Field, Dongpu Sag%深层高压低渗砂岩储层可动流体赋存特征及控制因素--以东濮凹陷文东沙三中油藏为例

    Institute of Scientific and Technical Information of China (English)

    王瑞飞; 齐宏新; 吕新华; 国殿斌

    2014-01-01

    利用核磁共振技术,对东濮凹陷文东沙三中深层高压低渗砂岩储层样品进行测试分析,通过可动流体百分数、可动流体孔隙度参数分析了可动流体的赋存特征及控制因素。研究结果表明,不同离心力的T2谱形态表现为4种类型,T2截止值与物性呈正相关关系。可动流体含量低且其分布具有较强的非均质性,渗透率越高,主流喉道半径越大,可动流体参数值越大,可动流体参数与渗透率的相关关系越好;渗透率越低,可动流体参数衰减越快。储层微观孔隙结构是可动流体赋存的主要控制因素。应用喉道半径区间分布表征微观孔隙结构对可动流体分布的控制,效果较好。物性越好,大喉道控制的可动流体量越高。%The samples of the deep-buried high-pressure and low-permeability sandstone reservoirs in the middle section of the 3rd member of the Shahejie Formation in the Wendong Oil Field of the Dongpu Sag were tested with nuclear magnetic resonance technique. The characteristics and controlling factors of movable fluid were analyzed with movable fluid percentage and porosity. The results have shown that the T2 pattern of the samples displays 4 modes, and the T2 cutoff value is positively correlated with porosity. The movable fluid content is relatively low and the heterogeneity is intense. The higher the permeability is, the wider is the main throat radius. The relation between the movable fluid parameter and the permeability gets better with the increase of permeability. The mova-ble fluid parameter gets higher attenuation velocity with the decrease of permeability and has more sensitivity to the changes of permeability. The micro-pore structure determines the existing state of fluid in deep-buried high-pressure and low-permeability sandstone reservoir. Applying main throat radius, the micro-pore structure control-ling movable fluid was token, which has achieved good results

  5. Impact Metamorphism of Sandstones at Amguid Crater, Algeria

    Science.gov (United States)

    Sahoui, R.; Belhai, D.

    2016-08-01

    Amguid is a 450 m diameter sample crater; it is emplaced in Lower Devonian sandstones.We have carried out a petrographic study in order to investigate shock effects recorded in these sandstones and define shock stages in Amguid.

  6. Fractures and stresses in Bone Spring sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, J.C.; Warpinski, N.R.; Sattler, A.R.; Northrop, D.A.

    1990-09-01

    This project is a collaboration between Sandia National Laboratories and Harvey E. Yates Company being conducted under the auspices of the Oil Recovery Technology Partnership. The project seeks to apply perspectives related to the effects of natural fractures, stress, and sedimentology to the simulation and production of low-permeability gas reservoirs to low-permeability oil reservoirs as typified by the Bone Spring sandstones of the Permian Basin, southeast New Mexico. This report presents the results and analysis obtained in 1989 from 233 ft of oriented core, comprehensive suite of logs, various in situ stress measurements, and detailed well tests conducted in conjunction with the drilling of two development wells. Natural fractures were observed in core and logs in the interbed carbonates, but there was no direct evidence of fractures in the sandstones. However, production tests of the sandstones indicated permeabilities and behavior typical of a dual porosity reservoir. A general northeast trend for the maximum principal horizontal stress was observed in an elastic strain recovery measurements and in strikes of drilling-induced fractures; this direction is subparallel to the principal fracture trend observed in the interbed carbonates. Many of the results presented are believed to be new information for the Bone Spring sandstones. 57 figs., 18 tabs.

  7. Size effect of concrete and sandstone

    NARCIS (Netherlands)

    Van Vliet. M.R.A.; Van Mier, J.G.M.

    2000-01-01

    A series of uniaxial tension experiments has been conducted to investigate the size effect on strength and fracture energy of concrete and sandstone. The experiments were carried on specimens of six different sizes in a scale range of 1:32. Depending on the material and the curing conditions a stron

  8. Rate type isotach compaction of consolidated sandstone

    NARCIS (Netherlands)

    Waal, J.A. de; Thienen-Visser, K. van; Pruiksma, J.P.

    2015-01-01

    Laboratory experiments on samples from a consolidated sandstone reservoir are presented that demonstrate rate type compaction behaviour similar to that observed on unconsolidated sands and soils. Such rate type behaviour can have large consequences for reservoir compaction, surface subsidence and in

  9. Experimental strain analysis of Clarens Sandstone colonised by endolithic lichens

    OpenAIRE

    Wessels, D; Venter, D; Wessels, W.; L Wessels

    1995-01-01

    Endolithic lichens occur commonly on Clarens Sandstone in South Africa, where they significantly contribute to the weathering of sandstone by means of mechanical and chemical weathering processes. This preliminary investigation reports on the success- ful use of strain gauges in detecting strain differences between sandstone without epilithic lichens and sandstone colonised by the euendolithic lichen Lecidea aff. sarcogynoides Korb. Mechanical weathering, expressed as strain changes, in Clare...

  10. Emplacement of sandstone intrusions during contractional tectonics

    Science.gov (United States)

    Palladino, Giuseppe; Grippa, Antonio; Bureau, Denis; Alsop, G. Ian; Hurst, Andrew

    2016-08-01

    Sandstone injections are created by the forceful emplacement of remobilized sand in response to increases in overpressure. However, the contribution provided by horizontal compressive stress to the build-up in overpressure, and the resulting emplacement of sand injection complexes, is still to be substantiated by robust field observations. An opportunity to address this issue occurs in Central California where a large volume of sandstone intrusions record regionally-persistent supra-lithostatic pore-pressure. Detailed fieldwork allows sandstone-filled thrusts to be recognized and, for the first time, permits us to demonstrate that some sandstone intrusions are linked to contractional deformation affecting the western border of the Great Valley Basin. Fluidized sand was extensively injected along thrust surfaces, and also fills local dilatant cavities linked to thrusting. The main aims of this paper are to provide detailed descriptions of the newly recognized syn-tectonic injections, and describe detailed cross-cutting relationships with earlier sandstone injection complexes in the study area. Finally, an evolutionary model consisting of three phases of sand injection is provided. In this model, sand injection is linked to contractional tectonic episodes affecting the western side of the Great Valley Basin during the Early-Middle Cenozoic. This study demonstrates that sand injections, driven by fluid overpressure, may inject along thrusts and folds and thereby overcome stresses associated with regional contractional deformation. It is shown that different generations of sand injection can develop in the same area under the control of different stress regimes, linked to the evolving mountain chain.

  11. 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

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    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

  12. Provenance, diagenesis, tectonic setting and reservoir quality of the sandstones of the Kareem Formation, Gulf of Suez, Egypt

    Science.gov (United States)

    Zaid, Samir M.

    2013-09-01

    The Middle Miocene Kareem sandstones are important oil reservoirs in the southwestern part of the Gulf of Suez basin, Egypt. However, their diagenesis and provenance and their impact on reservoir quality, are virtually unknown. Samples from the Zeit Bay Oil Field, and the East Zeit Oil Field represent the Lower Kareem (Rahmi Member) and the Upper Kareem (Shagar Member), were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower Rahmi sandstones have an average framework composition of Q95F3.4R1.6, and 90% of the quartz grains are monocrystalline. By contrast, the Upper Shagar sandstones are only slightly less quartzose with an average framework composition of Q76F21R3 and 82% of the quartz grains are monocrystalline. The Kareem sandstones are mostly quartzarenite with subordinate subarkose and arkose. Petrographical and geochemical data of sandstones indicate that they were derived from granitic and metamorphic terrains as the main source rock with a subordinate quartzose recycled sedimentary rocks and deposited in a passive continental margin of a syn rift basin. The sandstones of the Kareem Formation show upward decrease in maturity. Petrographic study revealed that dolomite is the dominant cement and generally occurs as fine to medium rhombs pore occluding phase and locally as a grain replacive phase. Authigenic quartz occurs as small euhedral crystals, locally as large pyramidal crystals in the primary pores. Authigenic anhydrites typically occur as poikilotopic rhombs or elongate laths infilling pores but also as vein filling cement. The kaolinite is a by-product of feldspar leaching in the presence of acidic fluid produced during the maturation of organic matter in the adjacent Miocene rocks. Diagenetic features include compaction; dolomite, silica and anhydrite cementation with minor iron-oxide, illite, kaolinite and pyrite cements; dissolution of feldspars, rock fragments. Silica dissolution, grain replacement and

  13. Supporting members

    Science.gov (United States)

    Life Supporting Members L. Thomas Aldrich Thomas D. Barrow Hugh J . A. Chivers Allan V. Cox Samuel S. Goldich Pembroke J. Hart A. Ivan Johnson Helmut E. Landsberg Paolo Lanzano Murli H. Manghnani L. L. Nettleton Charles B. Officer Hyman Orlin Ned A. Ostenso Erick O. Schonstedt Waldo E. Smith Athelstan Spilhaus A. F. Spilhaus, Jr. John W. Townsend, Jr. James A. Van Allen Leonard W. Weis Charles A. Whitten J. Tuzo Wilson

  14. Experimental Analysis of Sandstone and Travertine

    Directory of Open Access Journals (Sweden)

    T. Doležel

    2004-01-01

    Full Text Available Sandstone and travertine are sedimentary rocks. The former is clastic, while the latter is sourced by chemical precipitation from hot springs. Their applications in civil engineering structures are mostly influenced by the ability to carry compression loading. A three-point bending experiment is usually used to determine material characteristics. However it does not correspond very well to applicatiosn in structures. For this reason we used a uniaxial compression test to obtain the modulus of elasticity and the stress-strain diagram. To obtain detailed information about the crystalline structure of sandstone and travertine a microscopic analysis wascarried out, using optical microscopy and an EDAX multichannel spectrometer for elementary microanalysis. 

  15. Performance of Different Acids on Sandstone Formations

    Directory of Open Access Journals (Sweden)

    M. A. Zaman

    2013-12-01

    Full Text Available Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Some of these reactions may result in formation damage. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. It is a mixture of hydrofluoric (HF and hydrochloric (HCl acids designed to dissolve clays and siliceous fines accumulated in the near-wellbore region. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50% to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid – Hydrofluoric with Concentration (3% HF – 12% HCl. This paper presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results calculated are porosity, permeability, and FESEM Analysis and Strength tests. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  16. Wettability changes in trichloroethylene-contaminated sandstone.

    Science.gov (United States)

    Harrold, G; Gooddy, D C; Lerner, D N; Leharne, S A

    2001-04-01

    It is usually assumed that chlorinated solvent nonaqueous-phase liquids (NAPLs) are nonwetting with respect to water-saturated porous media. The focus of this work was to examine whether this supposition is appropriate for used trichloroethylene (TCE) samples. In this work, the term "used" indicates that the sample has been employed industrially and therefore contains solutes and breakdown products related to its previous use. The data obtained in this study indicate that exposure of initially water wet quartz slides to industrially used solvents can cause a contact angle change, measured through the aqueous phase, of 100 degrees with a maximum stable contact angle of 170 degrees (indicative of strong NAPL wetting characteristics) being recorded. The work on quartz slides was complemented by the use of sandstone cores. Wettability was measured using the Amott test. Used TCE again proved able to alter the wetting properties of sandstone to neutral wetting. The complexity of the industrially used samples precluded any realistic attempt to examine the agents causing these wetting changes. The data captured in these experiments were compared with laboratory grade TCE, and some attempts were made to synthesize known mixtures in order to replicate wetting changes. These experiments resulted in contact angle changes but did not alter the overall wettability of the quartz slides or sandstone cores. Finally the work reported here also demonstrates that increasing the duration of exposure to solvent has an important impact upon measured contact angle.

  17. Hydrofacies In Sandstones. Evidence For Feedback Between Sandstone Lithofacies and Permeability Development

    Science.gov (United States)

    Bloomfield, J. P.; Newell, A.; Moreau, M.

    In order to enhance our ability to develop effective numerical models of flow and con- taminant transport in the Permo-Triassic sandstone aquifer of the UK, relationships between lithofacies, rock mass characteristics (such as porosity and pore-throat size distribution), and permeability have been investigated through a series of case studies. Flow in the Permo-Triassic sandstones is primarily through the matrix. Permeability distribution is principally a function of the pore-throat size distribution and there is a relatively weak correlation with primary sedimentary lithofacies. It is observed that matrix permeability data broadly fall into two, discontinuous, sub-populations above and below about 1 mD. It is proposed that modification of primary sedimentary litho- facies by circulation of groundwater is the main control on the development of these two permeability sub-populations or hydrofacies. Identification of these two hydrofa- cies has significant implications for numerical modelling of the sandstones.

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

    Institute of Scientific and Technical Information of China (English)

    LI; ZiYing; FANG; XiHeng; CHEN; AnPing; OU; GuangXi; XIAO; XinJian; SUN; Ye; LIU; ChiYang; WANG; Yi

    2007-01-01

    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.

  19. Diagenesis of deep sandstone reservoirs and a quantitative model of porosity evolution: Taking the third member of Shahejie Formation in the Wendong Oilfield, Dongpu Sag, as an example%深层储集层成岩作用及孔隙度演化定量模型——以东濮凹陷文东油田沙三段储集层为例

    Institute of Scientific and Technical Information of China (English)

    王瑞飞; 沈平平; 赵良金

    2011-01-01

    The diagenesis and porosity evolution in the deep 3rd member of Shahejie Formation of the Wendong Oilfield was analyzed using thin-sections, casting thin-sections, X-ray diffractometry, scanning electron micrograph observations, and other data. Sandstone reservoirs are currently at the late diagenetic period. Pores consist of primary pores and the inter-granular dissolved and intra-granular dissolved pores of feldspar, debris and carbonate cements. Physical properties are mainly controlled by carbonate cementation and dissolution, and distribution of abnormally high fluid pressure. The evolution of porosity parameters shows that primary porosity is 36.75%, the porosity loss rate is 40.49% during the process of mechanic compaction, the porosity loss rate is 37.25% during the process of cementation and metasomasis, and the porosity increase rate is 17.88% during the process of dissolution. The proportion of primary porosity is 55.03%, and that of the secondary porosity is 44.97%. The error rate in the quantitative study of porosity is 0.96%, and the main influencing factor of the error rate is sorting coefficient of detrital rock (So).%利用普通薄片、铸体薄片、X射线衍射、扫描电镜等资料,分析东濮凹陷文东油田沙三段深层储集层砂岩成岩作用和孔隙演化过程.研究表明,储集层砂岩目前处于晚成岩阶段,储集层发育原生粒间孔隙和长石、岩屑、胶结物等不稳定组分的粒间溶孔、粒内溶孔.储集层物性分布受碳酸盐等的胶结、溶蚀及异常高压带分布的控制.孔隙度参数演化分析表明,储集层初始孔隙度为36.75%,压实过程孔隙度损失率为40.49%,胶结-交代过程孔隙度损失率为37.25%,后期溶蚀、溶解过程孔隙度增加率为17.88%.储集空间中原生孔隙占总孔隙的55.03%,次生孔隙占总孔隙的44.97%.孔隙度计算过程中误差率为0.96%,影响误差的主要因素为颗粒分选系数.

  20. The migration of uranium through sandstone

    International Nuclear Information System (INIS)

    Three column experiments are described in which the migration of uranium through Clashach Sandstone was studied. A priori predictions of uranium migration in the experiments were made using an equilibrium chemical transport model. The experimental results showed that, even under oxidising conditions, the migration of uranium is strongly retarded owing to the affinity of uranium for mineral surfaces. For the relatively simple chemical system investigated, the chemical transport model was successful in predicting the migration of uranium and its distribution along the column. (author)

  1. INAA and petrological study of sandstones from the Angkor monuments

    International Nuclear Information System (INIS)

    We determined 35 major, minor and trace elements in sandstone samples taken from building blocks of 19 Angkor temples and from an old and a new quarry using INAA. We also characterized the sandstone samples with conventional microscopy and electron microprobe analysis. Using cluster analysis, we found no straightforward correlation between the chemical/petrological properties of the sandstones and a presumed period of individual temples construction. The poor correlation may result either from the inherent inhomogeneity of sandstone or just reflect the diversity of quarries that supplied building blocks for the construction of any particular temple. (author)

  2. Age of the Bedford Shale, Berea Sandstone, and Sunbury Shale in the Appalachian and Michigan basins, Pennsylvania, Ohio, and Michigan

    Science.gov (United States)

    De Witt, Wallace

    1970-01-01

    The suggestion by Sanford (1967, p. 994) that the Bedford Shale, Berea Sandstone, and Sunbury Shale of the Michigan basin are of Late Devonian age because these strata contain Hymenozonotriletes lepidophytus Kedo is invalid for these formations in the Appalachian basin, the area of their type localities. Endosporites lacunosus Winslow, a synonym of Hymenozonotriletes lepidophytus Kedo, occurs in upper Chautauqua (Upper Devonian) rocks through much of the Kinderhook (Lower Mississippian) strata in Ohio. The Sunbury Shale, the Sunbury Member of the Orangeville Shale in part of northern Ohio, contains a Siplionodella fauna which clearly demonstrates the Kinderhook age of the unit. The basal strata of the Bedford Shale contain Spathoffnathodus anteposlcornis which suggests a very Late Devonian or very Early Mississippian age for this part of the Bedford. Except for the basal fossil zone, most of the Bedford Shale and the younger Berea Sandstone overlie the Murrysville sand, which along the Allegheny Front in central Pennsylvania contains an Adiantites flora of Early Mississippian (Kinderhook) age. The presence of Adiantites in the Murrysville sand indicates that most of the Bedford Shale and all the Berea Sandstone are of Early Mississippian age. Lithostratigraphic evidence suggests that the Berea Sandstone of Ohio may be a temporal equivalent of the basal Beckville Member of the Pocono Formation of the Anthracite region of Pennsylvania. The clearly demonstrable Kinderhook age of the Sunbury, Berea, and most of the Bedford in the Appalachian basin strongly indicates a similar age for the same units in the Michigan basin.

  3. Advantages of Shear Wave Seismic in Morrow Sandstone Detection

    Directory of Open Access Journals (Sweden)

    Paritosh Singh

    2011-01-01

    Full Text Available The Upper Morrow sandstones in the western Anadarko Basin have been prolific oil producers for more than five decades. Detection of Morrow sandstones is a major problem in the exploration of new fields and the characterization of existing fields because they are often very thin and laterally discontinuous. Until recently compressional wave data have been the primary resource for mapping the lateral extent of Morrow sandstones. The success with compressional wave datasets is limited because the acoustic impedance contrast between the reservoir sandstones and the encasing shales is small. Here, we have performed full waveform modeling study to understand the Morrow sandstone signatures on compressional wave (P-wave, converted-wave (PS-wave and pure shear wave (S-wave gathers. The contrast in rigidity between the Morrow sandstone and surrounding shale causes a strong seismic expression on the S-wave data. Morrow sandstone shows a distinct high amplitude event in pure S-wave modeled gathers as compared to the weaker P- and PS-wave events. Modeling also helps in understanding the adverse effect of interbed multiples (due to shallow high velocity anhydrite layers and side lobe interference effects at the Morrow level. Modeling tied with the field data demonstrates that S-waves are more robust than P-waves in detecting the Morrow sandstone reservoirs.

  4. Isotach formulation of the rate type compaction model for sandstone

    NARCIS (Netherlands)

    Pruiksma, J.P.; Breunese, J.N.; Thienen-Visser, K. van; Waal, J.A. de

    2015-01-01

    This paper presents a new formulation of the Rate Type Compaction Model (RTCM) for sandstone based on the isotach concept. The RTCM was originally developed to explain the loading rate dependent compaction behaviour observed in laboratory test on unconsolidated and consolidated sandstone samples and

  5. Mechanism of Solid Bitumen in Silurian Sandstones of Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    Zhang Jinglian; Zhu Bingquan

    1997-01-01

    @@ There are a large amount of solid bitumen within Silurian sandstones in Tabei, Tazhong, Kalpin uprifts of the Tarim Basin. Petroleum geochemists are interested in the super giant fossil oil pool. Unfortunately,some key questions have not been solved, such as: what generated the bitumen? When did the bitumen generate and when did the bitumen accumulated in the sandstones?

  6. Brittle and compaction creep in porous sandstone

    Science.gov (United States)

    Heap, Michael; Brantut, Nicolas; Baud, Patrick; Meredith, Philip

    2015-04-01

    Strain localisation in the Earth's crust occurs at all scales, from the fracture of grains at the microscale to crustal-scale faulting. Over the last fifty years, laboratory rock deformation studies have exposed the variety of deformation mechanisms and failure modes of rock. Broadly speaking, rock failure can be described as either dilatant (brittle) or compactive. While dilatant failure in porous sandstones is manifest as shear fracturing, their failure in the compactant regime can be characterised by either distributed cataclastic flow or the formation of localised compaction bands. To better understand the time-dependency of strain localisation (shear fracturing and compaction band growth), we performed triaxial deformation experiments on water-saturated Bleurswiller sandstone (porosity = 24%) under a constant stress (creep) in the dilatant and compactive regimes, with particular focus on time-dependent compaction band formation in the compactive regime. Our experiments show that inelastic strain accumulates at a constant stress in the brittle and compactive regimes leading to the development of shear fractures and compaction bands, respectively. While creep in the dilatant regime is characterised by an increase in porosity and, ultimately, an acceleration in axial strain to shear failure (as observed in previous studies), compaction creep is characterised by a reduction in porosity and a gradual deceleration in axial strain. The overall deceleration in axial strain, AE activity, and porosity change during creep compaction is punctuated by excursions interpreted as the formation of compaction bands. The growth rate of compaction bands formed during creep is lower as the applied differential stress, and hence background creep strain rate, is decreased, although the inelastic strain required for a compaction band remains constant over strain rates spanning several orders of magnitude. We find that, despite the large differences in strain rate and growth rate

  7. Subsurface sandstone mapping by combination of GPR and ERT method

    Institute of Scientific and Technical Information of China (English)

    YOU Zhixin

    2016-01-01

    It is important to know the shape and distribution of sandstone bodies in the subsurface when forma-tion and migration of a dune model are determined.The information plays a significant role in identification of the continental oil and gas accumulation.In this study,the combination of ground penetrating radar (GPR) and electrical resistivity tomography method (ERT)is used in mapping the distribution of sandstone bodies in Yanchang Formation.Six GPR profiles and seven ERT profiles are used to analysis.GPR data show clear re-flections from the top interface of sandstones.ERT data show a continuous high resistivity anomaly correspon-ding to the sandstone body.Combined the reconstructed 3D images by GPR and ERT,the spatial distribution of sandstone bodies is described.

  8. Dilatant hardening of fluid-saturated sandstone

    Science.gov (United States)

    Makhnenko, Roman Y.; Labuz, Joseph F.

    2015-02-01

    The presence of pore fluid in rock affects both the elastic and inelastic deformation processes, yet laboratory testing is typically performed on dry material even though in situ the rock is often saturated. Techniques were developed for testing fluid-saturated porous rock under the limiting conditions of drained, undrained, and unjacketed response. Confined compression experiments, both conventional triaxial and plane strain, were performed on water-saturated Berea sandstone to investigate poroelastic and inelastic behavior. Measured drained response was used to calibrate an elasto-plastic constitutive model that predicts undrained inelastic deformation. The experimental data show good agreement with the model: dilatant hardening in undrained triaxial and plane strain compression tests under constant mean stress was predicted and observed.

  9. Are the sandstone miners’ abuses in India?

    Directory of Open Access Journals (Sweden)

    Absar Ahmad

    2015-06-01

    Full Text Available Despite engaged in economic activities, the situation of sandstone miners is very poor in India. They are abused in many ways like in socioeconomic status, in Physical health, by doctors, by thekedars (contractor, by dacoits and by the administration. This report is compiled on the basis of author Ph.D. field work scheduled in May to September 2014 in 10 sampled villages in Karauli, Rajasthan and collected information from more than 300 mine workers and two in-depth interviews from local newspaper journalists.Karauli is a district of Rajasthan in western India, located at 26.5°N 77.02°E and encompasses an area of 5530 sq km. Located at a distance of 190 km from pink city Jaipur; the maximum temperature here reaches 470C in summers and minimum drops to about 40C in winters! The area is mainly famous for pink colored construction stone used for carving and other decorative materials. The livelihood of the rural population of this district is mainly agriculture, animal husbandry, and mining; with about one-third population dependent on mining for their livelihood. The sandstone famously called Karauli stone is mined here, mostly as an unorganized way. Despite engaged in economic activities and mentioned in the census under Industrial category (Mining and quarrying, the situation of these miners is very poor. They are abused in many ways like in socioeconomic status, in Physical health, by doctors, by thekedars (contractor, by dacoits and by the administration. 

  10. Relationship between characteristics of fan-delta sandstone bodies and in-situ leachable sandstone-type uranium mineralization

    International Nuclear Information System (INIS)

    Like normal deltas, fan-deltas are composed of three parts, i.e., fan-delta plain, fan-delta front and pre-fin-delta, In-situ leachable uranium deposits are commonly distributed along the margins of in-land basins. The author analyzes the possible relationship between the basic characteristics of fan-delta sandstone bodies and uranium mineralization. Two examples, e.g., the fan delta depositional systems in the eastern part of Jungger basin and the southern part of Yili basin, are given to illustrate the fan-delta vertical sequence and planar distribution of sedimentary facies. It has been pointed out that the braided channel sandstone bodies on delta plain, sub-aqueous distributional channel sandstone bodies and delta front sandstone bodies may be the favourable host rocks for in-situ leachable sandstone uranium deposits

  11. A two scale analysis of tight sandstones

    Science.gov (United States)

    Adler, P. M.; Davy, C. A.; Song, Y.; Troadec, D.; Hauss, G.; Skoczylas, F.

    2015-12-01

    Tight sandstones have a low porosity and a very small permeability K. Available models for K do not compare well with measurements. These sandstones are made of SiO_2 grains, with a typical size of several hundreds of micron. These grains are separated by a network of micro-cracks, with sizes ranging between microns down to tens of nm. Therefore, the structure can be schematized by Voronoi polyhedra separated by plane and permeable polygonal micro-cracks. Our goal is to estimate K based on a two scale analysis and to compare the results to measurements. For a particular sample [2], local measurements on several scales include FIB/SEM [3], CMT and 2D SEM. FIB/SEM is selected because the peak pore size given by Mercury Intrusion Porosimetry is of 350nm. FIB/SEM imaging (with 50 nm voxel size) identifies an individual crack of 180nm average opening, whereas CMT provides a connected porosity (individual crack) for 60 nm voxel size, of 4 micron average opening. Numerical modelling is performed by combining the micro-crack network scale (given by 2D SEM) and the 3D micro-crack scale (given by either FIB/SEM or CMT). Estimates of the micro-crack density are derived from 2D SEM trace maps by counting the intersections with scanlines, the surface density of traces, and the number of fracture intersections. K is deduced by using a semi empirical formula valid for identical, isotropic and uniformly distributed fractures [1]. This value is proportional to the micro-crack transmissivity sigma. Sigma is determined by solving the Stokes equation in the micro-cracks measured by FIB/SEM or CMT. K is obtained by combining the two previous results. Good correlation with measured values on centimetric plugs is found when using sigma from CMT data. The results are discussed and further research is proposed. [1] Adler et al, Fractured porous media, Oxford Univ. Press, 2012. [2] Duan et al, Int. J. Rock Mech. Mining Sci., 65, p75, 2014. [3] Song et al, Marine and Petroleum Eng., 65, p63

  12. Attenuation of Landfill Leachate In Unsaturated Sandstone

    Science.gov (United States)

    Butler, A. P.; Brook, C.; Godley, A.; Lewin, K.; Young, C. P.

    Landfill leachate emanating from old "dilute and disperse" sites represents a potential (and in many cases actual) threat to the integrity of groundwater. Indeed, this concern has been included in EU legislation (80/86/EEC), where key contaminants (e.g. ammonia, various toxic organic compounds and heavy metals) are explicitly highlighted in terms of their impact on groundwater. In the UK, whilst there are a substantial number of unlined landfills sited on major aquifers, many of these are in locations where there is a substantial unsaturated zone. Thus, there exists the opportunity for the modification and attenuation of contaminants prior to it encountering the water table. An understanding of likely changes in leachate content and concentrations at such sites will enable a more comprehensive assessment of the potential risks and liabilities posed by such sites to be evaluated. The Burntstump landfill, situated 8 km north of Nottingham (UK), is sited on an outcrop of Sherwood sandstone. The fine friable sand has been quarried since the 1960s and the excavated volume used to store municipal waste. Filling at the site commenced in the mid 1970s and originally was unlined. In 1978 the first of what was to become a series of boreholes was installed within an area of roughly 5 m radius over one of the original waste cells. Cores of the waste and underlying sandstone were extracted and analysed for a range of physical and chemical parameters. The most recent set of analyses were obtained in 2000. The series of investigations therefore provide an important record of leachate migration and modification through the unsaturated zone for over twenty years. The progression of the leachate front is clearly delineated by the chloride concentration profile with an average velocity of around 1.6 m.yr-1. Combining this value with an average (and reasonably uniform) measured moisture content of about 7% gives a mean inter-granular specific discharge of 110 mm.yr-1. An interesting

  13. Study on the cutting plane friction law of sandstone

    Institute of Scientific and Technical Information of China (English)

    ZHAI Ying-da (翟英达); KANG Li-xun(康立勋)

    2003-01-01

    The friction characteristics of rock damage plane have important impact on the stability of block structure formed after the stratum is broken. The mechanics properties of rock damage plane are described by parameters such as roughness coefficient, wall compress strength and basic friction angle. These three coefficients for fine grain sandstone and medium-granular sandstone and grit sandstone are test. The friction stress is researched at the condition of different normal compressive stress acting on the tension damage plane. The friction law of tension damage plane of sandstone abided by is summed up. This law will provide scientific basis for block structure stability judging in basic roof stratum and roof pressure intensity calculating.

  14. Size effect of sandstone after high temperature under uniaxial compression

    Institute of Scientific and Technical Information of China (English)

    SU Hai-jian; JING Hong-wen; MAO Xian-biao; ZHAO Hong-hui; YIN Qian; WANG Chen

    2015-01-01

    Uniaxial compression tests on sandstone samples with five different sizes after high temperature processes were performed in order to investigate the size effect and its evolution. The test results show that the density, longitudinal wave velocity, peak strength, average modulus and secant modulus of sandstone decrease with the increase of temperature, however, peak strain increases gradually. With the increase of ratio of height to diameter, peak strength of sandstone decreases, which has an obvious size effect. A new theoretical model of size effect of sandstone material considering the influence of temperature is put forward, and with the increase of temperature, the size effect is more apparent. The threshold decreases gradually with the increase of temperature, and the deviations of the experimental values and the theoretical values are between 0.44% and 6.06%, which shows quite a credibility of the theoretical model.

  15. Experimental Impact Cratering into Sandstone: A MEMIN-Progress Report

    Science.gov (United States)

    Poelchau, M. H.; Deutsch, A.; Kenkmann, T.; Hoerth, T.; Schäfer, F.; Thoma, K.; Memin Team

    2011-03-01

    The MEMIN Project is currently focused on impact experiments into sandstone. First results are presented here, including the evaluation of high-speed cameras, ejecta catchment devices, crater morphology, and chemical projectile-target interaction.

  16. Refuge Management Plan: Sandstone Unit Rice Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Part I of this management plan for the Sandstone Unit of Rice Lake NWR summarizes background information on the location, history, environment, resources,...

  17. The Creep Properties of Fine Sandstone under Uniaxial Tensile Stress

    OpenAIRE

    Jiang Haifei; Xie Yuanguang; Zhao Baoyun; Xue Kaixi

    2015-01-01

    A graduated uniaxial direct tensile creep test for fine sandstone is conducted by adopting a custom-designed direct tensile test device for rock. The experiment shows that the tensile creep of fine sandstone has similar creep curve patterns to those of compression creep, while the ratios of the creep strain to the total strain obtained in the tensile tests are substantially higher than those obtained for similar compression tests, which indicates that the creep ability of rock in the...

  18. Micropore Structure Representation of Sandstone in Petroleum Reservoirs Using an Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    BAI Yong-Qiang; ZHU Xing; WU Jun-Zheng; BAI Wen-Guang

    2011-01-01

    @@ The pore structure of sandstone in an oil reservoir is investigated using atomic force microscopy(AFM).At nanoscale resolution,AFM images of sandstone show us the fine structure.The real height data of images display the three-dimensional space structure of sandstone effectively.The three-dimensional analysis results show that the AFM images of sandstone have unique characteristics that,like fingerprints,can identify different structural properties of sandstones.The results demonstrate that AFM is an effective method used to represent original sandstone in petroleum reservoirs,and may help geologists to appreciate the sandstone in oil reservoirs fully.

  19. Key Elements Controlling Oil Accumulation within the Tight Sandstones

    Institute of Scientific and Technical Information of China (English)

    Haiyan Hu; Zhiping Zeng; Jianzhang Liu

    2015-01-01

    Tight oil sandstone reservoirs with low porosity and permeability, which are an uncon-ventional petroleum resource, have been discovered in the Jurassic intervals of the central Junggar Ba-sin, the northwestern China. To reveal the accumulation mechanism, a relatively comprehensive re-search was conducted, including oil-source correlation, porosity evolution, and hydrocarbon charging history. The results show that crude oil of these tight sandstone reservoirs were mainly from Permian source rocks with some contribution from Jurassic source rocks. The reservoirs were buried at shallow depth (5%). In contrast, the sandstone reservoir had already become tight and did not provide available space to ac-cumulate oil due to severe compaction and cementation when hydrocarbon from Jurassic source rock filled, evidenced by low GOI values (<5%). Therefore, reservoir porosity controls the oil accumulation within tight sandstone. Whether tight sandstone reservoirs accumulate oil depends on the reservoir quality when hydrocarbons charge. Before the exploration of tight oil sandstone reservoirs, it should be required to investigate the relationship between oil charging history and porosity evolution to reduce the exploration risk and figure out the available targets.

  20. Diagenesis Along Fractures in an Eolian Sandstone, Gale Crater, Mars

    Science.gov (United States)

    Ming, D. W.; Yen, A. S.; Rampe, E. B.; Grotzinger, J. P.; Blake, D. F.; Bristow, T. F.; Chipera, S. J.; Downs, R.; Morris, R. V.; Morrison, S. M.; Vaniman, D. T.; Gellert, R.; Sutter, B.; Treiman, A. H.

    2016-01-01

    The Mars Science Laboratory rover Curiosity has been exploring sedimentary deposits in Gale crater since August 2012. The rover has traversed up section through approx.100 m of sedimentary rocks deposited in fluvial, deltaic, lacustrine, and eolian environments (Bradbury group and overlying Mount Sharp group). The Stimson formation lies unconformable over a lacustrine mudstone at the base of the Mount Sharp group and has been interpreted to be a cross-bedded sandstone of lithified eolian dunes. Mineralogy of the unaltered Stimson sandstone consists of plagioclase feldspar, pyroxenes, and magnetite with minor abundances of hematite, and Ca-sulfates (anhydrite, bassanite). Unaltered sandstone has a composition similar to the average Mars crustal composition. Alteration "halos" occur adjacent to fractures in the Stimson. Fluids passing through these fractures have altered the chemistry and mineralogy of the sandstone. Silicon and S enrichments and depletions in Al, Fe, Mg, Na, K, Ni and Mn suggest aqueous alteration in an open hydrologic system. Mineralogy of the altered Stimson is dominated by Ca-sulfates, Si-rich X-ray amorphous materials along with plagioclase feldspar, magnetite, and pyroxenes, but less abundant in the altered compared to the unaltered Stimson sandstone and lower pyroxene/plagioclase feldspar. The mineralogy and geochemistry of the altered sandstone suggest a complicated history with several (many?) episodes of aqueous alteration under a variety of environmental conditions (e.g., acidic, alkaline).

  1. Siderite (FeCO3)—the Hidden (but Primary) Player in Iron Diagenesis of Non-Marine Sandstones

    Science.gov (United States)

    Loope, D.; Kettler, R. M.

    2015-12-01

    Siderite precipitates in reducing pore waters in which iron reduction exceeds sulfate reduction. Abundant siderite should be expected in non-marine strata in which a reductant was present. The Triassic Shinarump Member (Chinle Fm) and Cretaceous Dakota Fm are fluvial and contain siderite in outcrops of floodplain mudstones. Siderite is present in cores of Dakota channel sandstones. Rinded and jointed iron-oxide concretions, Wonderstone patterns, and rhombic, iron-oxide pseudomorphs are present in outcrops of these sandstones. Vascular plants growing on floodplains provided the reductant. Similar concretions, patterns, and pseudomorphs are present in outcropping eolian cross-strata of the Jurassic Navajo Sandstone and in fluvial sandstone of the Cambrian Umm Ishrin Fm. Bleached sandstones indicate reductant was present in both units during late diagenesis. Because Jurassic deserts and Cambrian river systems lacked vascular plants, extra-formational methane was the likely reductant. We interpret the various iron-oxide-cemented phenomena of the Shinarump, Dakota, Navajo, and Umm Ishrin as products of siderite oxidation that accompanied exhumation. In the Navajo, large concretions are enclosed in thick sheaths of iron-oxide cement. Through-going horizontal and vertical joints cut sheaths. Outside concretion sheaths, joints are unassociated with iron-oxide cements, but inside the sheaths, thick cement zones are present on both sides of (still-open) joints. Joints were conduits for oxidizing water entering the concretions. Redox gradients formed on both sides of joints and iron oxide accumulated as Fe+2 diffused from dissolving siderite toward joints and O2 diffused away from joints. Horizontal joints formed <100 m from the land surface. Iron-oxide accumulations on the horizontal joints and on the vertical joints that abut them (see figure) are evidence that siderite oxidation is ongoing and linked to exhumation.

  2. Dynamic triggering during rupture nucleation in sandstone

    Science.gov (United States)

    Schubnel, Alexandre; Chanard, Kristel; Latour, Soumaya; Petrelis, François; Hatano, Takahiro; Mair, Karen; Vinciguerra, Sergio

    2016-04-01

    Fluid induced stress perturbations in the crust at seismogenic depths can be caused by various sources, such as deglaciation unloading, magmatic intrusion or fluid injection and withdrawal. Numbers of studies have robustly shown their link to earthquake triggering. However, the role of small periodic stress variations induced by solid earth and oceanic tides or seasonal hydrology in the seismic cycle, of the order of a few kPa, remains unclear. Indeed, the existence or absence of correlation between these loading phenomena and earthquakes have been equally proposed in the literature. To investigate this question, we performed a set of triaxial deformation experiments on porous water-saturated Fontainebleau sandstones. Rock samples were loaded by the combined action of steps of constant stress (creep), intended to simulate tectonic loading and small sinusoidal pore pressure variations with a range of amplitudes, analogous to tides or seasonal loading. All tests were conducted at a regulated temperature of 35C and a constant 35 MPa confining pressure. Our experimental results show that (1) pore pressure oscillations do not seem to influence the deformation rate at which the rock fails, (2) they correlate with acoustic emissions. Even more interestingly, we observe a progressive increase of the correlation coefficient in time as the rock approaches failure. The correlation coefficient is also sensitive to the amplitude of pore pressure oscillations as larger oscillations produce higher correlation levels. Finally, we show that, in the last hours of creep before failure, acoustic emissions occur significantly more when the pore pressure is at its lowest. This suggest that the correlation of small stress perturbations and acoustic emissions depend on the state stress of a rock and the amplitude of the perturbations and that emissions occur more likely when cracks are unclamped.

  3. Sedimentary microfacies of the H8 member in the Su14 3D seismic test area

    Institute of Scientific and Technical Information of China (English)

    Zhang Yuqing; Wang Zhizhang

    2011-01-01

    The distribution of sedimentary microfacies in the eighth member of the Shihezi formation (the H8 member) in the Sul4 3D seismic test area was investigated. A Support Vector Machine (SVM) model was introduced for the first time as a way of predicting sandstone thickness in the study area. The model was constructed by analysis and optimization of measured seismic attributes. The distribution of the sedimentary microfacies in the study area was determined from predicted sandstone thickness and an analysis of sedimentary characteristics of the area. The results indicate that sandstone thickness predictions in the study area using an SVM method are good. The distribution of the sedimentary microfacies in the study area has been depicted at a fine scale.

  4. PRELIMINARY ESTIMATE OF CO2 STORAGE CAPACITY BY PETROPHYSICAL MODELLING IN UPPER MIOCENE POLJANA SANDSTONES IN THE WESTERN PART OF THE SAVA DEPRESSION

    Directory of Open Access Journals (Sweden)

    Marija Podbojec

    2016-02-01

    Full Text Available A preliminary assessment of the capacity of regional geological storage in the western part of the Sava Depression was based on data obtained from several deep exploration wells. The Poljana Sandstones represent a regional deep sandstone body, in most parts saturated with water, with promising underground facilities for the storage of CO₂ in the study area. Poljana Sandstones (member of Kloštar-Ivanić Formation bounded between E-log markers Rνand Z' have favourable petrophysical properties and are situated at reasonable depths. According to previous investigations, at depths greater than 800 meters supercritical conditions of temperature and pressure CO₂ are achieved, which ensures easy and safe injection into storage underground facilities. For the creation of a model in Petrel software, various data was used, including the distribution of CO₂ density, porosity, effective thickness and the relative depth of sandstone. Spatial distribution of porosity was made regarding neutron porosity logs. The most important parameter in the estimate of storage capacity is effective thickness, defined by the interval between E–log markers Rν and Z’. Hence, the effective thickness was used for top and bottom surface of sandstones. Density of CO₂ was created according to their spatial distribution regarding the depth and the temperature. The capacity of CO2 storage was calculated by the volumetric method. The use of a calculated Petrel model can subsequently determine the amount of CO₂ storage in the underground facilities of the study area.

  5. Erosion characteristic of slope sandstone soaking in acid mine drainage

    Institute of Scientific and Technical Information of China (English)

    JIANG Li-chun; CHEN Jia-sheng; WU Ai-xiang

    2007-01-01

    Acid mine drainage(AMD) is one of the main reasons of slope instability in chemical mines with high sulfide. The pH values of the solution inside the mining pit decrease with the increasing of distance from ore body and vary from 1.2 to 4.6,according to the results of the water environmental investigation and the composition test of the slope sandstone in Xinqiao Pyrite Mine. Comparative experiments between original sandstone and AMD eroded sandstone samples show that after AMD erosion the uniaxial compressive strength and elastic modulus decrease by 30%-50% and 25%-45%, respectively, the cohesion and internal friction angle decrease obviously, and the Poisson ratio fluctuates between 0.20-0.29. The greater joints development, the higher residual stress after peak value, and the longer time to damage. Besides above, the reaction mechanism analysis of AMD eroded sandstone shows that the fillings in joints and fissures of sandstone are frequently decomposed and polyreacted, resulting in changes of interior molecule structure and framework composition, and decreases of cohesion and angle of internal friction between rock structure interfaces.

  6. A new Basal sauropodomorph dinosaur from the Lower Jurassic Navajo sandstone of Southern Utah.

    Directory of Open Access Journals (Sweden)

    Joseph J W Sertich

    Full Text Available BACKGROUND: Basal sauropodomorphs, or 'prosauropods,' are a globally widespread paraphyletic assemblage of terrestrial herbivorous dinosaurs from the Late Triassic and Early Jurassic. In contrast to several other landmasses, the North American record of sauropodomorphs during this time interval remains sparse, limited to Early Jurassic occurrences of a single well-known taxon from eastern North America and several fragmentary specimens from western North America. METHODOLOGY/PRINCIPAL FINDINGS: On the basis of a partial skeleton, we describe here a new basal sauropodomorph dinosaur from the Lower Jurassic Navajo Sandstone of southern Utah, Seitaad ruessi gen. et sp. nov. The partially articulated skeleton of Seitaad was likely buried post-mortem in the base of a collapsed dune foreset. The new taxon is characterized by a plate-like medial process of the scapula, a prominent proximal expansion of the deltopectoral crest of the humerus, a strongly inclined distal articular surface of the radius, and a proximally and laterally hypertrophied proximal metacarpal I. CONCLUSIONS/SIGNIFICANCE: Phylogenetic analysis recovers Seitaad as a derived basal sauropodomorph closely related to plateosaurid or massospondylid 'prosauropods' and its presence in western North America is not unexpected for a member of this highly cosmopolitan clade. This occurrence represents one of the most complete vertebrate body fossil specimens yet recovered from the Navajo Sandstone and one of the few basal sauropodomorph taxa currently known from North America.

  7. Diagenetic effect on permeabilities of geothermal sandstone reservoirs

    DEFF Research Database (Denmark)

    Weibel, Rikke; Olivarius, Mette; Kristensen, Lars;

    The Danish subsurface contains abundant sedimentary deposits, which can be utilized for geothermal heating. The Upper Triassic – Lower Jurassic continental-marine sandstones of the Gassum Formation has been utilised as a geothermal reservoir for the Thisted Geothermal Plant since 1984 extracting...... and permeability is caused by increased diagenetic changes of the sandstones due to increased burial depth and temperatures. Therefore, the highest water temperatures typically correspond with the lowest porosities and permeabilities. Especially the permeability is crucial for the performance of the geothermal......-line fractures. Continuous thin chlorite coatings results in less porosity- and permeability-reduction with burial than the general reduction with burial, unless carbonate cemented. Therefore, localities of sandstones characterized by these continuous chlorite coatings may represent fine geothermal reservoirs...

  8. Effect Of Hot Water Injection On Sandstone Permeability

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Fabricius, Ida Lykke

    2012-01-01

    of published results regarding the effect of temperature on sandstone permeability. These tests are performed with mineral oil, nitrogen gas, distilled water and solutions of NaCl, KCl, CaCl2 as well as brines that contain a mixture of salts. Thirteen sandstone formations, ranging from quartz arenites....... Heating causes thermal expansion, which results in porosity reduction if the sandstone is confined. The maximum effect of porosity reduction as a result of thermal expansion on permeability is modelled and compared the change in specific surface that is computed from the reported data. This does...... not account for all the permeability reductions observed. Permeablity reduction occurs both when distilled water is the saturating fluid as well as in tests with NaCl, KCl or CaCl2 solutions, however, this is not the case in tests with mineral oil or nitrogen gas. The formation of a filter cake or influx...

  9. Effective Thermal Conductivity Modeling of Sandstones: SVM Framework Analysis

    Science.gov (United States)

    Rostami, Alireza; Masoudi, Mohammad; Ghaderi-Ardakani, Alireza; Arabloo, Milad; Amani, Mahmood

    2016-06-01

    Among the most significant physical characteristics of porous media, the effective thermal conductivity (ETC) is used for estimating the thermal enhanced oil recovery process efficiency, hydrocarbon reservoir thermal design, and numerical simulation. This paper reports the implementation of an innovative least square support vector machine (LS-SVM) algorithm for the development of enhanced model capable of predicting the ETCs of dry sandstones. By means of several statistical parameters, the validity of the presented model was evaluated. The prediction of the developed model for determining the ETCs of dry sandstones was in excellent agreement with the reported data with a coefficient of determination value ({R}2) of 0.983 and an average absolute relative deviation of 0.35 %. Results from present research show that the proposed LS-SVM model is robust, reliable, and efficient in calculating the ETCs of sandstones.

  10. Viscoelastic BISQ Model for Low-Permeability Sandstone with Clay

    Institute of Scientific and Technical Information of China (English)

    NIE Jian-Xin; YANG Ding-Hui

    2008-01-01

    @@ A modified BISQ (Blot/Squirt) model for wave propagation in low-permeability sandstone is developed by in-troducing the viscoelastic mechanism of a porous skeleton into Dvorkin's model. The linear viscoelasticity of the Kelvin-Voigt constitutive law is employed to describe the stress-strain relation of a solid frame with clay while the ultrasonic waves propagate through the fluid-saturated sandstone. The phase velocity and attenuation of two p-waves are given based on the present BISQ model. The comparisons between numerical results and experimental data indicate that our viscoelastic model is more realistic and feasible for wave propagation in the low-permeability sandstone, especially with clay, than traditional BISQ models.

  11. Optical coherence tomography for vulnerability assessment of sandstone.

    Science.gov (United States)

    Bemand, Elizabeth; Liang, Haida

    2013-05-10

    Sandstone is an important cultural heritage material, in both architectural and natural settings, such as neolithic rock art panels. The majority of deterioration effects in porous materials such as sandstone are influenced by the presence and movement of water through the material. The presence of water within the porous network of a material results in changes in the optical coherence tomography signal intensity that can be used to monitor the wetting front of water penetration of dry porous materials at various depths. The technique is able to detect wetting front velocities from 1 cm s(-1) to 10(-6) cm s(-1), covering the full range of hydraulic conductivities likely to occur in natural sandstones from pervious to impervious.

  12. The effect of hot water injection on sandstone permeability

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Haugwitz, Christian; Jacobsen, Peter Sally Munch;

    2014-01-01

    Seasonal energy storage can be achieved by hot water injection in geothermal sandstone aquifers. We present an analysis of literature data in combination with new short-term flow through permeability experiments in order to address physical and physico-chemical mechanisms that can alter permeabil......Seasonal energy storage can be achieved by hot water injection in geothermal sandstone aquifers. We present an analysis of literature data in combination with new short-term flow through permeability experiments in order to address physical and physico-chemical mechanisms that can alter...

  13. Natural and Laboratory-Induced Compaction Bands in Aztec Sandstone

    Science.gov (United States)

    Haimson, B. C.; Lee, H.

    2002-12-01

    The Aztec sandstone used in this research is from the Valley of Fire State Park area, Nevada. This Jurassic aeolian sandstone is extremely weak (uniaxial compressive strength of 1-2 MPa); porosity averages 26%; grains are subrounded and have a bimodal size distribution (0.1 mm and 0.5 mm); its mineral composition (K. Sternlof, personal comm.) is 93% quartz, 5% k-spar, and 2% kaolinite, Fe carbonate and others; grain bonding is primarily through suturing. Sternlof et al. (EOS, November, 2001) observed substantial exposure of mainly compactive deformation bands in the Aztec sandstone. We studied an SEM image of a compaction band found in a hand sample of the Aztec sandstone. We also conducted a drilling test in a 130x130x180 mm prismatic specimen subjected to a preset far-field true triaxial stress condition (\\sigmah = 15 MPa, \\sigmav = 25 MPa, \\sigmaH = 40 MPa). Drilling of a 20 mm dia. vertical hole created a long fracture-like thin tabular breakout along the \\sigmah springline and perpendicular to \\sigmaH direction. SEM analysis of the zones ahead of the breakout tips revealed narrow bands of presumed debonded intact grains interspersed with grain fragments. We infer that the fragments were formed from multiple splitting or crushing of compacted grains in the band of high compressive stress concentration developed along the \\sigmah springline. SEM images away from the breakout tip surroundings showed no such fragments. SEM study of the natural compaction band showed a similar arrangement of mainly intact grains surrounded by grain fragments. Using the Optimas optical software package, we found the percentage of pore area within the band ahead of the breakout tips to average 17%; outside of this zone it was 23%. In the natural compaction band pore area occupied 8.5% of the band; in the host rock adjacent to the compaction band it averaged 19%. These readings strongly suggest porosity reduction due to compaction in both cases. The close resemblance between the

  14. A new bee species that excavates sandstone nests.

    Science.gov (United States)

    Orr, Michael C; Griswold, Terry; Pitts, James P; Parker, Frank D

    2016-09-12

    Humanity has long been fascinated by animals with apparently unfavorable lifestyles [1]. Nesting habits are especially important because they can limit where organisms live, thereby driving population, community, and even ecosystem dynamics [2]. The question arises, then, why bees nest in active termite mounds [3] or on the rim of degassing volcanoes, seemingly preferring such hardship [4]. Here, we present a new bee species that excavates sandstone nests, Anthophora (Anthophoroides) pueblo Orr (described in Supplemental Information, published with this article online), despite the challenges already inherent to desert life. Ultimately, the benefits of nesting in sandstone appear to outweigh the associated costs in this system. PMID:27623257

  15. On cavity flow permeability testing of a sandstone.

    Science.gov (United States)

    Selvadurai, P A; Selvadurai, A P S

    2007-01-01

    This paper describes a laboratory experiment designed to measure the bulk permeability of a cuboidal sample of sandstone measuring approximately 450 mm(2) in plan area and 508 mm in height. The relatively large dimensions of the sandstone specimen allow the determination of the permeability of the material by creating a central cavity that can be pressurized to maintain a constant flow rate. The paper describes the experimental details and the test procedure, and discusses the computational and analytic approaches that have been used to interpret the test results.

  16. A new bee species that excavates sandstone nests.

    Science.gov (United States)

    Orr, Michael C; Griswold, Terry; Pitts, James P; Parker, Frank D

    2016-09-12

    Humanity has long been fascinated by animals with apparently unfavorable lifestyles [1]. Nesting habits are especially important because they can limit where organisms live, thereby driving population, community, and even ecosystem dynamics [2]. The question arises, then, why bees nest in active termite mounds [3] or on the rim of degassing volcanoes, seemingly preferring such hardship [4]. Here, we present a new bee species that excavates sandstone nests, Anthophora (Anthophoroides) pueblo Orr (described in Supplemental Information, published with this article online), despite the challenges already inherent to desert life. Ultimately, the benefits of nesting in sandstone appear to outweigh the associated costs in this system.

  17. Bacterial communities in pigmented biofilms formed on the sandstone bas-relief walls of the Bayon Temple, Angkor Thom, Cambodia.

    Science.gov (United States)

    Kusumi, Asako; Li, Xianshu; Osuga, Yu; Kawashima, Arata; Gu, Ji-Dong; Nasu, Masao; Katayama, Yoko

    2013-01-01

    The Bayon temple in Angkor Thom, Cambodia has shown serious deterioration and is subject to the formation of various pigmented biofilms. Because biofilms are damaging the bas-reliefs, low reliefs engraved on the surface of sandstone, information about the microbial community within them is indispensable to control biofilm colonization. PCR-denaturing gradient gel electrophoresis (DGGE) analysis of biofilm samples from the pigmented sandstone surfaces showed that the bacterial community members in the biofilms differed clearly from those in the air and had low sequence similarity to database sequences. Non-destructive sampling of biofilm revealed novel bacterial groups of predominantly Rubrobacter in salmon pink biofilm, Cyanobacteria in chrome green biofilm, Cyanobacteria and Chloroflexi in signal violet biofilm, Chloroflexi in black gray biofilm, and Deinococcus-Thermus, Cyanobacteria, and Rubrobacter in blue green biofilm. Serial peeling-off of a thick biofilm by layers with adhesive sheets revealed a stratified structure: the blue-green biofilm, around which there was serious deterioration, was very rich in Cyanobacteria near the surface and Chloroflexi in deep layer below. Nitrate ion concentrations were high in the blue-green biofilm. The characteristic distribution of bacteria at different biofilm depths provides valuable information on not only the biofilm formation process but also the sandstone weathering process in the tropics.

  18. Altitude of the bottom of the Trinidad Sandstone in the Raton Basin, Las Animas County, Colorado

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of structure contours that show lines of equal altitude of the bottom of the Trinidad Sandstone, the contact between the Trinidad Sandstone...

  19. Diagenesis, provenance and depositional environments of the Bunter Sandstone Formation

    DEFF Research Database (Denmark)

    Olivarius, Mette; Weibel, Rikke; Friis, Henrik;

    The Bunter Sandstone Formation in the northern North German Basin has large geothermal potential with high porosity and permeability (generally >15% and >100 mD, respectively) and with pore fluid temperatures that are adequate for geothermal energy production (c. 55–60˚C). A combined investigation...

  20. Inelastic compaction, dilation and hysteresis of sandstones under hydrostatic conditions

    Science.gov (United States)

    Shalev, Eyal; Lyakhovsky, Vladimir; Ougier-Simonin, Audrey; Hamiel, Yariv; Zhu, Wenlu

    2014-05-01

    Sandstones display non-linear and inelastic behaviour such as hysteresis when subjected to cyclic loading. We present three hydrostatic compaction experiments with multiple loading-unloading cycles on Berea and Darley Dale sandstones and explain their hysteretic behaviour using non-linear inelastic compaction and dilation. Each experiment included eight to nine loading-unloading cycles with increasing maximum pressure in each subsequent cycle. Different pressure-volumetric strain relations during loading and unloading were observed. During the first cycles, under relatively low pressures, not all of the volumetric strain is recovered at the end of each cycle whereas at the last cycles, under relatively high pressures, the strain is recovered and the pressure-volumetric strain hysteresis loops are closed. The observed pressure-volumetric strain relations are non-linear and the effective bulk modulus of the sandstones changes between cycles. Observations are modelled with two inelastic deformation processes: irreversible compaction caused by changes in grain packing and recoverable compaction associated with grain contact adhesion, frictional sliding on grains or frictional sliding on cracks. The irreversible compaction is suggested to reflect rearrangement of grains into a more compact mode as the maximum pressure increases. Our model describes the `inelastic compaction envelope' in which sandstone sample will follow during hydrostatic loading. Irreversible compaction occurs when pressure is greater than a threshold value defined by the `inelastic compaction envelope'.

  1. Negative feedback between stress and erosion: origin of sandstone landforms

    Science.gov (United States)

    Bruthans, Jiri; Soukup, Jan; Vaculikova, Jana; Filippi, Michal; Schweigstillova, Jana; Mayo, Alan; Masin, David; Kletetschka, Gunther; Rihosek, Jaroslav

    2015-04-01

    Weathering and erosion of sandstone produces spectacular landforms such as arches, alcoves, pedestal rocks and pillars. The effect of gravity loading stress has been overlooked or assumed to increase the landform's weathering rate. Here we show by physical and numerical modeling, and field observations of locked sands and sandstones that an increase in stress within the landform reduces weathering and erosion. Material with insufficient loading is rapidly removed by weathering process and the remaining load bearing landform structure is protected by the fabric interlocking mechanism. As the landform evolves the increased stress inhibits erosion from raindrop impact, flowing water and slaking, and retards surface retreat caused by salt and frost weathering. Planar discontinuities in sandstone and negative feedback between stress and weathering/erosion processes are sufficient conditions to create above-mentioned landforms. Our experiments are able to reproduce natural shapes including arches, alcoves, pedestal rocks and pillars using landform material and mimicking natural processes. The proposed negative feedback mechanism is supported by a numerical model of stress pattern in landforms. We conclude that stress field is the primary control of the shape evolution of sandstone landforms.

  2. Transport properties of a Bentheim sandstone under deformation.

    Science.gov (United States)

    Jasinski, L; Sangaré, D; Adler, P M; Mourzenko, V V; Thovert, J-F; Gland, N; Békri, S

    2015-01-01

    The mechanical and transport properties of a Bentheim sandstone are studied both experimentally and numerically. Three classical classes of loads are applied to a sample whose permeability is measured. The elasticity and the Stokes equations are discretized on unstructured tetrahedral meshes which precisely follow the deformations of the sample. Numerical results are presented, discussed, and compared to the available experimental data.

  3. DELAYED POLYMER CROSSLINKING USED FOR PROFILE CONTROL IN SANDSTONE RESERVOIRS

    Institute of Scientific and Technical Information of China (English)

    Wang Zhongmao; Dong Bo; Fu Xiaofeng; Rong Jiashu

    1997-01-01

    @@ Most of the oil reservoirs in Jilin province occur in fractured sandstone with low permeability and heavy heterogeneity. In addition, with fracture development, the artificial fractures around producing wells and water injection wells have been increased, further aggravating the heterogeneity of oil reservoirs.

  4. Continuity and internal properties of Gulf Coast sandstones and their implications for geopressured fluid production

    Energy Technology Data Exchange (ETDEWEB)

    Morton, R.A.; Ewing, T.E.; Tyler, N.

    1983-01-01

    The intrinsic properties of the genetic sandstone units that typify many geopressured geothermal aquifers and hydrocarbon reservoirs in the Gulf Coast region were systematically investigated classified, and differentiated. The following topics are coverd: structural and stratigraphic limits of sandstone reservoirs, characteristics and dimensions of Gulf Coast sandstones; fault-compartment areas; comparison of production and geologic estimates of aquifer fluid volume; geologic setting and reservoir characteristics, Wells of Opportunity; internal properties of sandstones; and implications for geopressured fluid production. (MHR)

  5. An experimental study of iron release from red sandstones

    Science.gov (United States)

    Purser, Gemma; Rochelle, Christopher; Rushton, Jeremy; Pearce, Jonathan

    2014-05-01

    An experimental study has been conducted to better understand the features of a natural CO2 -rich system at Saltwash Graben, Utah, USA. This site is associated with numerous CO2 rich springs linked to faults and fractures. In this area, a key feature of the red Entrada sandstone formation is the presence of significant rock bleaching (iron reduction and mobilisation) that occurs subparallel to bedding, typically at the base of large sandstone units and adjacent to some subvertical fractures. The difference in total iron content between the bleached and unbleached sandstones is very small, with the bleached sandstone containing slightly less total iron. In contrast to widely-reported regional bleaching, attributed to hydrocarbon accumulations towards structural crests, it has been suggested that the bleaching may be associated with the presence of modern day CO2 in the area and we sought to test this. Laboratory experiments were conducted to assess reaction processes that may have caused the observed iron reduction and mobilisation. Fixed volume batch reactors, containing either small cores of red or bleached sandstone were exposed to representative local ground waters (a dilute or a saline fluid), which were pressurised with either CO2 or N2 (the latter as a control) to 50 bar and placed inside an oven at 40° C to simulate subsurface conditions . The experiments ran for up to nine months with fluids being sampled periodically, though solids were only analysed once experiments were completed. Very little reaction was found to occur in the presence of CO2. It seems possible therefore that the modern CO2 rich fluids were not the cause of the sandstone bleaching. The study therefore assessed how the presence of reducing agents such as methane (CH4) and hydrogen sulphide (H2S) may result in the bleaching of the bulk sandstone. H2S was introduced into the experiments as a breakdown product of thioacetamide (0.1% v/v fluid containing thioacetamide was added to the

  6. Traces of the heritage arising from the Macelj sandstone

    Science.gov (United States)

    Golež, Mateja

    2014-05-01

    The landscape of Southeast Slovenia and its stone heritage principally reveal itself through various Miocene sandstones. The most frequently found type on the borderline between Slovenia and Croatia, i.e. east of Rogatec, is the micaceous-quartz Macelj sandstone. This rock ranges in colour from greenish grey to bluish grey and yellowish, depending on the content of glauconite, which colours it green. In its composition, the rock is a heterogeneous mixture of grains of quartz, dolomite, muscovite, microcline, anorthite and glauconite. The average size of grains is 300μm. In cross-section, they are oblong, semi-rounded or round. The mechanical-physical and durability properties of the Macelj sandstone, which have been characterised pursuant to the applicable standards for natural stone, reveal that the rock exhibits poor resistance to active substances from the atmosphere, particularly in the presence of salt. In the surroundings of Rogatec, there are around 45 abandoned quarries of the Macelj sandstone, which are the result of the exploitation of this mineral resource from the 17th century on. The local quarrymen earned their bread until 1957, when the Kambrus quarry industry closed down. From the original use of this mineral resource as construction and decorative material, the useful value of the Macelj sandstone expanded during the development of the metals industry to the manufacture of large and small grindstones for the needs of the domestic and international market. Therefore, traces of quarrying can not only be seen in the disused quarries, but also in the rich architectural heritage of Rogatec and its surroundings, the stone furniture - from portals, window frames, wells, various troughs, pavements to stone walls - and other. The living quarrying heritage slowly passed into oblivion after World War II, although the analysis of the social image of the people residing in Rogatec and its surroundings revealed that there was an average of one stonemason in

  7. True Tri-axial testing of Castlegate Sandstone

    Science.gov (United States)

    Ingraham, M. D.; Issen, K.; Holcomb, D.

    2009-12-01

    Deformation bands in high porosity sandstone are an important geological feature for geologists and petroleum engineers; however, their formation is not fully understood. Axisymmetric compression, the common test for this material, is not sufficient to fully evaluate localization criteria. This study seeks to investigate the influence of the second principal stress on the failure and the formation of deformation bands in Castlegate sandstone. Experimental results from tests run in the axisymmetric compression stress state, as well as a stress state between axisymmetric compression and pure shear will be presented. Samples are tested using a custom triaxial testing rig at Sandia National Laboratories capable of applying stresses up to 400 MPa. Acoustic emissions are used to locate deformation bands should they not be visible on the specimen exterior. It is suspected that the second invariant of stress has a strong contribution to the failure mode and band formation. These results could have significant bearing on petroleum extraction as well as carbon dioxide sequestration.

  8. Comparative study between Botucatu and Berea sandstone properties

    Science.gov (United States)

    Cardoso, Oldemar Ribeiro; Balaban, Rosangela de Carvalho

    2015-10-01

    The aim of the present study is the analysis and comparison between Berea and Botucatu sandstone, concerning the problems with regard to the loss of permeability or water sensitivity or loss of hydraulic conductivity due to the presence of swelling or non-swelling clays. Some porous volumes of synthetic seawater of different salinities were displaced through the porous media of Berea and Botucatu formations. It was observed that even the plugs of Berea, with no-swelling clays in their composition, had the permeability reduced as soon as the brine salinity reached a lower limit. As expected, the same occurred with the Botucatu sandstone samples, however, in this case,the sensitivity to the low salinity was much more effective.

  9. Mineralogy and uranium leaching of ores from Triassic Peribaltic sandstones

    OpenAIRE

    Gajda, Dorota; Kiegiel, Katarzyna; Zakrzewska-Koltuniewicz, Grazyna; Chajduk, Ewelina; Bartosiewicz, Iwona; Wolkowicz, Stanislaw

    2014-01-01

    The recovery of uranium and other valuable metals from Polish Peribaltic sandstones were examined. The solid–liquid extraction is the first stage of the technology of uranium production and it is crucial for the next stages of processing. In the laboratory experiments uranium was leached with efficiencies 71–100 % by acidic lixiviants. Satisfactory results were obtained for the alkaline leaching process. Almost 100 % of uranium was leached with alkaline carbonate solution. In post leaching so...

  10. Paleoecology of Early Jurassic Navajo Sandstone Interdune Deposits

    OpenAIRE

    Wilkens, Nathan Daniel

    2008-01-01

    The Lower Jurassic Navajo Sandstone represents a desert that covered more than 366,000 square kilometers. Localized interdune deposits commonly occur along the eastern edge of this desert that include carbonates, bioturbated layers, and plant fossils. Previous studies of these deposits focused on specific fossil types or isolated sites. This study involved a comprehensive analysis of the paleoecology of interdune deposits with an integrated approach combining paleontology, sedimentology and g...

  11. Strength and elastic properties of sandstone under different testing conditions

    Institute of Scientific and Technical Information of China (English)

    CHEN Yun-ping; WANG Si-jing; WANG En-zhi

    2007-01-01

    A laboratory experimental program performed on Wuhan sandstones was presented under monotonic loading, partial cyclic loading during loading path and sine wave cyclic loading with different strain rates to compare uniaxial compression strength and elastic properties (elastic modulus and Poisson ratio) under different conditions and influence of pore fluid on them. When the loading strain rates are 10-5, 10-4 and 10-3/s, uniaxial compression strengths of dry sandstones are 82.3, 126.6 and 141.6 MPa,respectively, and that of water saturated sandstones are 70.5, 108.3 and 124.1 MPa, respectively. The above results show that the uniaxial compression strength increases with the increase of strain rate, however, variation of softening coefficient is insignificant.Under monotonic loading condition, tangent modulus increases with an increment of stress (strain) to a maximum value at a certain stress level, beyond which it starts to decline. Under the partial cyclic loading during loading path condition, unloading or reloading modulus is larger than loading modulus, and unloading and reloading moduli are almost constants with respect to stress level,especially unloading modulus. Under the sine wave cyclic loading condition, tangent modulus and Poisson ratio display asymmetric 'X' shape with various strain, and the average unloading modulus is larger than the average loading modulus.

  12. Calcium lignosulfonate adsorption and desorption on Berea sandstone.

    Science.gov (United States)

    Grigg, Reid B; Bai, Baojun

    2004-11-01

    This paper describes adsorption and desorption studies carried out with calcium lignosulfonate (CLS) on Berea sandstone. Circulation experiments were performed to determine CLS adsorption isotherms and the effects of CLS concentration, temperature, salinity, brine hardness, and injection rate on adsorption density. Flow-through experiments were performed to assess the reversibility of CLS adsorption and the influence of postflush rate, brine concentration, brine hardness, brine pH, and temperature on the desorption process. Results indicate that CLS adsorption isotherms on Berea sandstone follow the Freundlich isotherm law. The results presented in this paper on the effects of CLS adsorption and desorption on Berea sandstone show that: (1) increasing CLS concentration and salinity increases CLS adsorption density; (2) increasing temperature will decrease adsorption density; (3) increasing injection rate of CLS solution will slightly decrease CLS adsorption density; (4) postflush rate and salinity of brine have a large impact on the CLS desorption process; (5) the adsorption and desorption process are not completely reversible; and (5) temperature and pH of the postflush brine have little effect on desorption.

  13. Auraticoccus monumenti gen. nov., sp. nov., an actinomycete isolated from a deteriorated sandstone monument.

    Science.gov (United States)

    Alonso-Vega, Pablo; Carro, Lorena; Martínez-Molina, Eustoquio; Trujillo, Martha E

    2011-05-01

    A Gram-type-positive, strictly aerobic actinobacterium, designated strain MON 2.2(T), was isolated from the surface of a sandstone monument. Cells with a coccoid shape, arranged in pairs or clusters, were non-motile and did not produce spores. The 10 closest 16S rRNA gene sequence matches (~95 % similarity) found in the public databases were uncultured actinobacteria, while the closest cultured members indicated a phylogenetic relationship with members of the family Propionibacteriaceae (92-95 % similarity). Subsequent phylogenetic analysis placed the new isolate within the radiation of the genera Friedmanniella and Microlunatus, but forming an independent branch. Chemotaxonomic markers were consistent with the classification of strain MON 2.2(T) in the family Propionibacteriaceae, amongst the genera containing ll-diaminopimelic acid in their peptidoglycan. Characteristic fatty acids iso-C(15 : 0) and anteiso-C(15 : 0) also supported its affiliation to this taxon; however, polar lipid and menaquinone compositions clearly differentiated strain MON 2.2(T) from other genera in the family. On the basis of these results and additional physiological data obtained in the present study, it is proposed that strain MON 2.2(T) be classified in a novel species in a new genus, for which the name Auraticoccus monumenti gen. nov., sp. nov. is proposed. The type strain of Auraticoccus monumenti is MON 2.2(T) ( = CECT 7672(T)  = DSM 23257(T)  = LMG 25551(T)).

  14. Physical and mechanical properties of sandstone containing a single fissure after exposure to high temperatures

    Institute of Scientific and Technical Information of China (English)

    Zhu Tantan; Jing Hongwen; Su Haijian; Yin Qian; Du Mingrui; Han Guansheng

    2016-01-01

    In order to investigate the physical and mechanical properties of sandstone containing fissures after exposure to high temperatures, fissures with different angles a were prefabricated in the plate sandstone samples, and the processed samples were then heated at 5 different temperatures. Indoor uniaxial com-pression was conducted to analyze the change rules of physical properties of sandstone after exposure to high temperature, and the deformation, strength and failure characteristics of sandstone containing fis-sures. The results show that, with increasing temperature, the volume of sandstone increases gradually while the quality and density decrease gradually, and the color of sandstone remains basically unchanged while the brightness increases markedly when the temperature is higher than 585 ?C;the peak strength of sandstone containing fissures first decreases then increases when the temperature is between 25 ?C and 400 ?C. The peak strain of sandstone containing fissures increases gradually while the average mod-ulus decreases gradually with increasing temperature, and the mechanical properties of sandstone show obvious deterioration after 400 ?C. The peak strain of sandstone containing fissures increases gradually while the average modulus decreases gradually with increasing temperature; with increasing angle a of the fissure, the evolution characteristics of the macro-mechanical parameters of sandstone are closely related to the their own mechanical properties. When the temperature is 800 ?C, the correlation between the peak strength and average modulus of sandstone and the angle a of the fissure is obviously weakened. The failure modes of sandstone containing fissures after high temperature exposure are of three different kinds including: tensile crack failure, tensile and shear cracks mixed failure, and shear crack failure. Tensile and shear crack mixed failure occur mainly at low temperatures and small angles;tensile crack failure occurs at high

  15. Petrology and stratigraphy of Paleogene nonmarine sandstones, Cascade Range, Washington

    Science.gov (United States)

    Frizzell, Virgil A.

    1979-01-01

    The Cascade Range of Washington north of 47? latitude is composed of probable Paleozoic and Mesozoic metamorphic rocks and Mesozoic and Tertiary plutonic rocks. Several Paleogene nonmarine arkosic sandstone units fringe and in part occur within the complex crystalline core. The early to middle Eocene Chuckanut Formation is present on the west side of the crystalline core in the western foothills of the Cascades. The early to middle Eocene Swauk Formation partially encircles the Mt. Stuart massif of the central Cascades. In the western foothills of the Cascades, between the main body of Chuckanut Formation near Bellingham and the main outcrop area of the Swauk Formation south of Mt. Stuart, many smaller bodies of arkosic sandstone have variously been referred to either the Swauk or Chuckanut Formations. The early Eocene Manastash Formation occurs locally in an area south of the Yakima River. The middle to late Eocene Chumstick Formation is mostly confined to the Chiwaukum graben within the crystalline core and is separated from the Swauk Formation on the southwest by the Leavenworth Fault. The Oligocene Wenatchee Formation unconformably over lies the Chumstick Formation near Wenatchee. The middle to late Eocene Roslyn Formation crops out north of the Yakima River and is underlain by the Teanaway Basalt which separates the Roslyn from the older Swauk Formation. The middle Eocene to early Oligocene Naches Formation forms a north-trending body that crosses the Yakima River and is in fault contact with both the Swauk and Manastash Formations. The middle to late Eocene Puget Group underlies the Quaternary deposits of the Puget Lowland southeast of Seattle on the western flank of the Cascades. The various formations are all composed predominantly of fine- to medium-grained sandstones with lesser amounts of interbedded shale, conglomerate and coal. Compositionally, the units are predominantly either feldspathic or litho-feldspathic subquartzose sandstones. Volcanic rocks

  16. Appalachian Basin Low-Permeability Sandstone Reservoir Characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Ray Boswell; Susan Pool; Skip Pratt; David Matchen

    1993-04-30

    A preliminary assessment of Appalachian basin natural gas reservoirs designated as 'tight sands' by the Federal Energy Regulatory Commission (FERC) suggests that greater than 90% of the 'tight sand' resource occurs within two groups of genetically-related units; (1) the Lower Silurian Medina interval, and (2) the Upper Devonian-Lower Mississippian Acadian clastic wedge. These intervals were targeted for detailed study with the goal of producing geologic reservoir characterization data sets compatible with the Tight Gas Analysis System (TGAS: ICF Resources, Inc.) reservoir simulator. The first phase of the study, completed in September, 1991, addressed the Medina reservoirs. The second phase, concerned with the Acadian clastic wedge, was completed in October, 1992. This report is a combined and updated version of the reports submitted in association with those efforts. The Medina interval consists of numerous interfingering fluvial/deltaic sandstones that produce oil and natural gas along an arcuate belt that stretches from eastern Kentucky to western New York. Geophysical well logs from 433 wells were examined in order to determine the geologic characteristics of six separate reservoir-bearing intervals. The Acadian clastic wedge is a thick, highly-lenticular package of interfingering fluvial-deltaic sandstones, siltstones, and shales. Geologic analyses of more than 800 wells resulted in a geologic/engineering characterization of seven separate stratigraphic intervals. For both study areas, well log and other data were analyzed to determine regional reservoir distribution, reservoir thickness, lithology, porosity, water saturation, pressure and temperature. These data were mapped, evaluated, and compiled into various TGAS data sets that reflect estimates of original gas-in-place, remaining reserves, and 'tight' reserves. The maps and data produced represent the first basin-wide geologic characterization for either interval. This report

  17. Population genetic structure of a sandstone specialist and a generalist heath species at two levels of sandstone patchiness across the Strait of Gibraltar.

    Directory of Open Access Journals (Sweden)

    Manuel Jesús Gil-López

    Full Text Available Many habitat specialist species are originally composed of small, discontinuous populations because their habitats are naturally fragmented or patchy. They may have suffered the long-term effects of natural patchiness. Mediterranean heathlands, a representative habitat in the Strait of Gibraltar region, are associated with nutrient-poor, acidic sandstone soils. Sandstone soil patches in the African side of the Strait (Tangier are, in general, smaller and more scattered than in the European side (Algeciras. In this study, we analyze the effect of this sandstone patchiness on the population genetic diversity and structure of two Erica species from these Mediterranean heathlands that differ in their edaphic specificity, E. australis, sandstone specialist, and E. arborea, generalist. Average levels of within-population genetic diversity and gene flow between populations were significantly lower in Tangier (high sandstone patchiness than in Algeciras (low patchiness for the sandstone specialist, whereas no differences between both sides of the Strait were detected in the edaphic generalist. Since most endemic species in Mediterranean heathlands of the Strait of Gibraltar are sandstone specialists, these results highlight an increased vulnerability to loss of genetic diversity and local extinction of the heathland endemic flora in the Tangier side of the Strait of Gibraltar.

  18. Population genetic structure of a sandstone specialist and a generalist heath species at two levels of sandstone patchiness across the Strait of Gibraltar.

    Science.gov (United States)

    Gil-López, Manuel Jesús; Segarra-Moragues, José Gabriel; Ojeda, Fernando

    2014-01-01

    Many habitat specialist species are originally composed of small, discontinuous populations because their habitats are naturally fragmented or patchy. They may have suffered the long-term effects of natural patchiness. Mediterranean heathlands, a representative habitat in the Strait of Gibraltar region, are associated with nutrient-poor, acidic sandstone soils. Sandstone soil patches in the African side of the Strait (Tangier) are, in general, smaller and more scattered than in the European side (Algeciras). In this study, we analyze the effect of this sandstone patchiness on the population genetic diversity and structure of two Erica species from these Mediterranean heathlands that differ in their edaphic specificity, E. australis, sandstone specialist, and E. arborea, generalist. Average levels of within-population genetic diversity and gene flow between populations were significantly lower in Tangier (high sandstone patchiness) than in Algeciras (low patchiness) for the sandstone specialist, whereas no differences between both sides of the Strait were detected in the edaphic generalist. Since most endemic species in Mediterranean heathlands of the Strait of Gibraltar are sandstone specialists, these results highlight an increased vulnerability to loss of genetic diversity and local extinction of the heathland endemic flora in the Tangier side of the Strait of Gibraltar.

  19. Simulation of channel sandstone architecture in an incised valley

    Energy Technology Data Exchange (ETDEWEB)

    Frykman, P.; Johannessen, P.; Andsbjerg, J.

    1998-12-31

    The present report describes a geostatistical modelling study that is aimed at reflecting the architecture of the channel sandstones in an incised valley fill. The example used for this study is a part of the Middle Jurassic sandy succession of the Bryne Formation in the Danish central Graben. The succession consists mainly of fluvial sediments in the lower part, overlain by tidal influenced sediments, which again is overlain by shallow marine sediments. The modelling study has been performed on a sequence of incised valley sediments in the upper part of the Bryne Formation overlying fluvial sediments. (au) EFP-96. 19 refs.

  20. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.

    1995-02-01

    This final report summarizes the progress during the three years of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description; (ii) scale-up procedures; (iii) outcrop investigation. The first section describes the methods by which a reservoir can be described in three dimensions. The next step in reservoir description is to scale up reservoir properties for flow simulation. The second section addresses the issue of scale-up of reservoir properties once the spatial descriptions of properties are created. The last section describes the investigation of an outcrop.

  1. Initiation of acoustic emission in fluid-saturated sandstone samples

    Science.gov (United States)

    Lapshin, V. B.; Patonin, A. V.; Ponomarev, A. V.; Potanina, M. G.; Smirnov, V. B.; Stroganova, S. M.

    2016-07-01

    A rock behavior experiment with uniaxial compression revealed the effect of acoustic activity in loaded fluid-saturated Berea sandstone samples in response to an electric current. It is established that it is substantially intensified in periods of the current impact and decreases after its cut-off. The current impact also results in a growth of radial deformation indicating an increase in the sample volume. The effect of acoustic activation increases in response to increased heat emitted by the electric current during its flow through the sample, which allows the discovered effect to be explained by initiation of its destruction due to thermal expansion of the fluid in rock interstices and fissures.

  2. Depositional environments of the early cretaceous Kurnub (Hathira) sandstones, North Jordan

    Science.gov (United States)

    Abed, Abdulkader M.

    1982-04-01

    The Kurnub (Hathira) sandstones in north Jordan, which are most probably of Early Cretaceous age, are about 300 m thick varicoloured, friable quartz-arenitic sandstones. Based on grain-size analysis, sedimentary structures, palaeocurrent, fossil content and petrography, these sandstones are postulated to be dominantly of fluvial origin with a few interfingering shallow marine horizons. A southward displacement of Jordan by at least 100 km would bring these sandstones opposite to similar rocks west of the Jordan-Araba rift, with Jordan being higher during the EArly Cretaceous.

  3. Greybull Sandstone Petroleum Potential on the Crow Indian Reservation, South-Central Montana

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, David A.

    2002-05-13

    The focus of this project was to explore for stratigraphic traps that may be present in valley-fill sandstone at the top of the Lower Cretaceous Kootenai Formation. This sandstone interval, generally known as the Greybull Sandstone, has been identified along the western edge of the reservation and is a known oil and gas reservoir in the surrounding region. The Greybull Sandstone was chosen as the focus of this research because it is an excellent, well-documented, productive reservoir in adjacent areas, such as Elk Basin; Mosser Dome field, a few miles northwest of the reservation; and several other oil and gas fields in the northern portion of the Bighorn Basin.

  4. Water Vapor Diffusion and Adsorption of Sandstones: Influence of Rock Texture and Composition

    Directory of Open Access Journals (Sweden)

    Martin Keppert

    2016-01-01

    Full Text Available The term sandstone is used for wide range of rocks containing quartz clasts which can be cemented by secondary precipitated quartz or calcite; moreover the space between clasts can be filled by matrix. These facts result in existence of numerous rocks having highly various properties. Sandstones have been used as construction materials due to their good accessibility and workability. Since most of sandstones are porous, water vapor can penetrate through sandstone constructions. The rate of water vapor diffusion, as well as the vapor sorption isotherm, was determined for range of sandstone types. The diffusion resistance factor was found to be dependent on the total porosity of sandstone but the sorption behavior was strongly influenced by nature of the particular sandstone; the specific surface area of stone and presence of clay matrix are determining its sorption isotherm. The published data enable estimating (i diffusion resistance factor of a sandstone via knowledge of its total porosity and (ii the sorption isotherm via knowledge of the stone’s nature and specific surface area. This approach can significantly reduce the time necessary to acquire vapor-related properties of a sandstone.

  5. Mechanical properties and failure characteristics of fractured sandstone with grouting and anchorage

    Institute of Scientific and Technical Information of China (English)

    Zong Yijiang; Han Lijun; Qu Tao; Yang Shengqi

    2014-01-01

    Based on uniaxial compression experimental results on fractured sandstone with grouting and anchorage, we studied the strength and deformation properties, the failure model, crack formation and evolution laws of fractured sandstone under different conditions of anchorage. The experimental results show that the strength and elastic modulus of fractured sandstone with different fracture angles are sig-nificantly lower than those of intact sandstone. Compared with the fractured samples without anchorage, the peak strength, residual strength, peak and ultimate axial strain of fractured sandstone under different anchorage increase by 64.5-320.0%, 62.8-493.0%, and 31.6-181.4%, respectively. The number of bolts and degree of pre-stress has certain effects on the peak strength and failure model of fractured sandstone. The peak strength of fractured sandstone under different anchorage increases to some extent, and the failure model of fractured sandstone also transforms from tensile failure to tensile-shear mixed failure with the number of bolts. The pre-stress can restrain the formation and evolution process of tensile cracks, delay the failure process of fractured sandstone under anchorage and impel the transformation of failure model from brittle failure to plastic failure.

  6. Trilobites from the Middle Ordovician Stairway Sandstone, Amadeus Basin, central Australia

    DEFF Research Database (Denmark)

    Jakobsen, Kristian Grube; Nielsen, Arne Thorshøj; Harper, David Alexander Taylor;

    2014-01-01

    During the Middle Ordovician (Darriwilian) sandstones and siltstones were deposited in the epicontinental Larapintine Sea, which covered large parts of central Australia. The Darriwilian Stairway Sandstone has, for the first time, been sampled stratigraphically for macrofossils to track marine...... benthic biodiversity in this clastic-dominated shallow-water palaeoenvironment situated along the margin of northeastern Gondwana. The faunas from the Stairway Sandstone are generally of low diversity and dominated by bivalves but include several animal groups, with trilobites representing 25......% of the entire shelly fauna. Thirteen trilobite taxa are described from the Stairway Sandstone; the fauna displays a high degree of endemism. One new species, Basilicus (Parabasilicus) brumbyensis sp. nov. is described....

  7. A spectroscopic investigation of the weathering of a heritage Sydney sandstone.

    Science.gov (United States)

    Ip, K H; Stuart, B H; Ray, A S; Thomas, P S

    2008-12-01

    Infrared spectroscopy has been employed in a study of the degradation of heritage Sydney sandstone used in St. Mary's Cathedral in Sydney, Australia. Spectra were used to characterise the clay components taken from weathered and unweathered sandstone blocks removed from the Cathedral as part of a restoration programme. Two types of kaolin clays - kaolinite and its polymorph, dickite - have been identified. A higher amount of dickite present in the clay of weathered sandstone indicated that a kaolinite-to-dickite transformation occurs upon weathering. X-ray photoelectron spectroscopy was also used to confirm the presence of a more thermally stable polymorph of the kaolinite in the sandstone.

  8. Deformation bands in porous sandstones their microstructure and petrophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Torabi, Anita

    2007-12-15

    Deformation bands are commonly thin tabular zones of crushed or reorganized grains that form in highly porous rocks and sediments. Unlike a fault, typically the slip is negligible in deformation bands. In this dissertation the microstructure and petrophysical properties of deformation bands have been investigated through microscopy and numerical analysis of experimental and natural examples. The experimental work consists of a series of ring-shear experiments performed on porous sand at 5 and 20 MPa normal stresses and followed by microscopic examination of thin sections from the sheared samples. The results of the ring-shear experiments and comparison of them to natural deformation bands reveals that burial depth (level of normal stress in the experiments) and the amount of shear displacement during deformation are the two significant factors influencing the mode in which grains break and the type of shear zone that forms. Two end-member types of experimental shear zones were identified: (a) Shear zones with diffuse boundaries, which formed at low levels of normal stress and/or shear displacement; and (b) Shear zones with sharp boundaries, which formed at higher levels of normal stress and/or shear displacement. Our interpretation is that with increasing burial depth (approximately more than one kilometer, simulated in the experiments by higher levels of normal stress), the predominant mode of grain fracturing changes from flaking to splitting; which facilitates the formation of sharp-boundary shear zones. This change to grain splitting increases the power law dimension of the grain size distribution (D is about 1.5 in sharp boundary shear zones). Based on our observations, initial grain size has no influence in the deformation behavior of the sand at 5 MPa normal stresses. A new type of cataclastic deformation band is described through outcrop and microscopic studies; here termed a 'slipped deformation band'. Whereas previously reported cataclastic

  9. Investigation of Sandstones Wetting by X-ray Microtomography

    Science.gov (United States)

    Marquesa, Leonardo C.; Appoloni, Carlos R.; Fernandes, Jaquiel S.; Nagata, Rodrigo

    2011-08-01

    X-ray microtomography is a non-destructive imaging technique. It consists in cross-sections object reconstruction based in the linear attenuation coefficient maps achieved through the object illuminating by a X-ray beam at different angular positions. It has been used by various researches to supply microstructural informations of materials as ceramic filters, pills, titanium prosthesis and reservoir rocks. An item of great interest has been the characterization of the liquid phase presence in porous space. This paper shows the X-ray microtomography methodology employed to achieve qualitative and quantitative results about Botucatu sandstones wetting. It was used a Skyscan, 1172 model, which employs an X-ray tube with W anode and a cone beam. This laboratory based equipment is able to provide images of until 1 μm spatial resolution. The employed samples were two cores of layered Botucatu sandstone, named ARN1 and ARN 2. These samples were scanned in two situations each one, dried and wet. 2D images, porosity values for each 2D image, total average porosity and pose size distribution for the dried and wet situation were compared. H20-NaCl-KI solution was employed for the samples wetting procedure. The two samples were scanned with 4.84 μm spatial resolution. The total average porosities obtained for ARN1 sample before and after wetting were 4.4±0.7% and 1.8±0.4%, respectively.

  10. The Creep Properties of Fine Sandstone under Uniaxial Tensile Stress

    Directory of Open Access Journals (Sweden)

    Jiang Haifei

    2015-09-01

    Full Text Available A graduated uniaxial direct tensile creep test for fine sandstone is conducted by adopting a custom-designed direct tensile test device for rock. The experiment shows that the tensile creep of fine sandstone has similar creep curve patterns to those of compression creep, while the ratios of the creep strain to the total strain obtained in the tensile tests are substantially higher than those obtained for similar compression tests, which indicates that the creep ability of rock in the tensile process is higher than that in the uniaxial compression process. Based on the elastic modulus in the approximately linear portion of the obtained isochronous stress-strain curves of the tensile creep, the time dependence of the elasticity modulus for the Kelvin model is evaluated, and a revised generalized Kelvin model is obtained by substitution into the generalized Kelvin model. A new viscousplastic model is proposed to describe the accelerated creep properties, and this model is combined in series with the revised generalized Kelvin model to form a new nonlinear viscoelastic-plastic creep model that can describe the properties of attenuation creep, steady creep, and accelerated creep. Comparison of the test and theoretical curves demonstrates that they are nearly identical, which verifies the performance of the model.

  11. Microstructural changes of sandstone specimens during CO2 injection

    Science.gov (United States)

    Park, J. H.; Son, J.; Oh, M.; Park, H. D.

    2014-12-01

    Carbon dioxide capture and storage (CCS) is a technology to isolate CO2 from atmosphere, by capturing it from sources, transporting it to injection area, and injecting it into suitable geological formation, ocean, or mineral carbonation plant. Geological storage of carbon dioxide is the most effective and economical method, and until now a lot of demonstration projects were carried out successfully such as Sleipner, Weyburn, and In Salah. In Republic of Korea, small-scale CO2 injection demonstration project is now under investigation in offshore Pohang Basin with sandstone reservoir and the mudstone caprock. When CO2 is injected in target site, the rock around injection well can be deteriorated because of extreme change of temperature and pressure. In this study supercritical CO2 was injected in sandstone specimen and the initiation and propagation of fracture inside the specimens were observed using X-ray computed tomography (CT). X-ray CT method is a computer technology to observe inner density of target object in three dimensional image. Because of its non-destructivity and high resolution, it is suitable for consistent observation of the same specimen. Porosity and permeability of the specimens were measured using X-ray CT images and both of them were increased after injection. P- and S-wave velocity were also measured to assess the change of mechanical property and both of them were decreased after injection because of growth of inner fractures. The data from this research can be used as input data of CCS site.

  12. Measuring the zeta potential. The relationships with sandstone fineness

    Directory of Open Access Journals (Sweden)

    de Luxán, M. P.

    1989-09-01

    Full Text Available The application of the zeta potential technique in the area of construction materials and Portland cement is quite recent. The initial research work involved the study of cement suspensions or suspensions of one of the components of cement, such as alite, tricalcium alumínate, in the presence of additives and, more specifically, superplasticizers. The studies of this sort were extended with the mixing of active additions into cement (fly ashes, etc.. The present study discusses the application of siliceous materials (sandstone as a basis of the research into the behaviour of sandstone mortars containing repair products.

    La aplicación de la técnica del potencial zeta en el campo de los materiales de construcción y del cemento portland es muy reciente. Las primeras investigaciones se refieren al estudio de suspensiones de cemento o de alguno de sus compuestos que lo forman como alita, aluminato tricálcico, en presencia de aditivos y, más concretamente, de superfluidificantes. Con la incorporación de adiciones activas al cemento (cenizas volantes,... se amplían los estudios de este tipo de cementos. En este trabajo se considera la aplicación a los materiales silíceos (arenisca como base para la investigación del comportamiento de los morteros de arenisca conteniendo productos de reparación.

  13. Water coning mechanism in Tarim fractured sandstone gas reservoirs

    Institute of Scientific and Technical Information of China (English)

    沈伟军; 刘晓华; 李熙喆; 陆家亮

    2015-01-01

    The problem of water coning into the Tarim fractured sandstone gas reservoirs becomes one of the major concerns in terms of productivity, increased operating costs and environmental effects. Water coning is a phenomenon caused by the imbalance between gravity and viscous forces around the completion interval. There are several controllable and uncontrollable parameters influencing this problem. In order to simulate the key parameters affecting the water coning phenomenon, a model was developed to represent a single well with an underlying aquifer using the fractured sandstone gas reservoir data of the A-Well in Dina gas fields. The parametric study was performed by varying six properties individually over a representative range. The results show that matrix permeability, well penetration (especially fracture permeability), vertical-to-horizontal permeability ratio, aquifer size and gas production rate have considerable effect on water coning in the fractured gas reservoirs. Thus, investigation of the effective parameters is necessary to understand the mechanism of water coning phenomenon. Simulation of the problem helps to optimize the conditions in which the breakthrough of water coning is delayed.

  14. Sandstone caves on Venezuelan tepuis: Return to pseudokarst?

    Science.gov (United States)

    Aubrecht, R.; Lánczos, T.; Gregor, M.; Schlögl, J.; Šmída, B.; Liščák, P.; Brewer-Carías, Ch.; Vlček, L.

    2011-09-01

    Venezuelan table mountains (tepuis) host the largest arenite caves in the world. The most frequently used explanation of their origin so far was the "arenization" theory, involving dissolution of quartz cement around the sand grains and subsequent removing of the released grains by water. New research in the two largest arenite cave systems - Churi-Tepui System in Chimanta Massif and Ojos de Cristal System in Roraima Tepui showed that quartz dissolution plays only a minor role in their speleogenesis. Arenites forming the tepuis are not only quartzites but they display a wide range of lithification and breakdown, including also loose sands and sandstones. Speleogenetic processes are mostly concentrated on the beds of unlithified sands which escaped from diagenesis by being sealed by the surrounding perfectly lithified quartzites. Only the so-called "finger-flow" pillars testify to confined diagenetic fluids which flowed in narrow channels, leaving the surrounding arenite uncemented. Another factor which influenced the cave-forming processes by about 30% was lateritization. It affects beds formed of arkosic sandstones and greywackes which show strong dissolution of micas, feldspars and clay minerals, turning then to laterite ("Barro Rojo"). The main prerequisite to rank caves among karst phenomena is dissolution. As the dissolution of silicate minerals other than quartz appears to play not only a volumetrically important role but even a trigger role, these arenitic caves may be ranked as karst.

  15. Distribution characteristics and petroleum geological significance of the Silurian asphaltic sandstones in Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Jun; PANG; Xiongqi; LIU; Luofu; JIANG; Zhenxue; LIU

    2004-01-01

    The Tarim Basin is a typical superimposed basin in which there have occurred multiphase adjustment and destruction of the reservoirs. The widely distributed asphaltic sandstones of the Silurian are the very product after destruction of the reservoirs. Studies show that the Silurian asphaltic sandstones distributed in both the middle and western parts on the basin are controlled chiefly by the Caledonian oil source area and by the Tazhong, Tabei and Bachu uplifts, whereas the distribution of the asphaltic sandstones on local structural belts is controlled by the reservoir's sedimentary system. Vertically, most of the asphaltic sandstones are under the regional caprock of red mudstones and the upper sandstone section of compact lithology. Due to the difference of hydrocarbon destruction in the early stage and the influence of hydrocarbon recharge in the late stage, the asphaltic sandstones and oil-bearing sandstones in the Tazhong area can be vertically divided into the upper and lower sections and they have an interactive distribution relationship as well. Asphaltic sandstones exist not only in intergranular pores but also inside the grains of sand and between the crevices, proving the destruction of early reservoirs due to uplifting. The existence of asphaltic sandstones over a large area reveals that the large-scale migration and accumulation and the subsequent destruction of hydrocarbons in the Craton area. The destruction caused a loss of the reserve resources of the Palaeozoic amounting to nearly 13.3 billion tons. Asphaltic sandstones formed after the destruction of oil and gas may serve as an effective caprock which is beneficial to accumulation of hydrocarbons and formation of the pool sealed by asphaltic sandstones in the later stage. The destruction of the early Silurian hydrocarbons depends on the stratigraphic burial depth. The deep part under the northern slope of Tazhong is an area favorable to search of undestroyed Silurian oil reservoirs.

  16. The thousandth ALICE member

    CERN Multimedia

    2006-01-01

    From left to right: Lodovico Riccati, Toru Sugitate and Jurgen Schukraft. On Friday 13 October, the ALICE Collaboration Board accepted, as full members, nine new institutes, bringing the number of scientists from 982 to 1015. To celebrate this event, Lodovico Riccati, Chair of the Collaboration Board, and Jurgen Schukraft, Spokesperson of the ALICE Experiment, presented a small award to the thousandth collaborator, Toru Sugitate, from Hiroshima University.

  17. [Comment on] BOSP members

    Science.gov (United States)

    Richman, Barbara T.

    The new Board on Ocean Science and Policy (BOSP) (Eos, June 7, 1983, p. 402) met for the first time on May 4. John B. Slaughter, former director of the National Science Foundation and now chancellor of the University of Maryland in College Park, is the board's chairman. Other board members are D. James Baker, Jr. (University of Washington, Seattle); Kirk Bryan (Geophysical Fluid Dynamics Laboratory, Princeton University); John P. Craven (University of Hawaii); Charles L. Drake (Dartmouth College); Paul M. Fye (Woods Hole Oceanographic Institution); Edward D. Goldberg (Scripps Institution of Oceanography); G. Ross Heath (Oregon State University); Judith T. Kildow (Massachusetts Institute of Technology); John A. Knauss (University of Rhode Island); James J. McCarthy (Museum of Comparative Zoology, Harvard University); H. William Menard (Scripps Institution of Oceanography); C. Barry Raleigh (Lamont-Doherty Geological Observatory); Roger Revelle (University of California, San Diego); David A. Ross (Woods Hole Oceanographic Institution); Brian J. Rothschild (University of Maryland); William M. Sackett (University of South Florida); John H. Steele (Woods Hole Oceanographic Institution); and Carl Wunsch (MIT). Wallace Broecker (Lamont-Doherty Geological Observatory), an original board member, resigned after the first meeting. Broecker told Eos that combining the science and policy boards resulted in a new board whose mission is too broad. A new board member will be appointed in Broecker's place

  18. Different effects of temperature and salinity on permeability reduction by fines migration in Berea sandstone

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Kjøller, Claus; Riis, Jacob Fabricius;

    2015-01-01

    Hot water injection into geothermal aquifers is considered in order to store energy seasonally. Berea sandstone is often used as a reference formation to study mechanisms that affect permeability in reservoir sandstones. Both heating of the pore fluid and reduction of the pore fluid salinity can...

  19. Localization of uranium rich mineralization in sandstone bodies, Akouta deposit, Republic of Niger

    Energy Technology Data Exchange (ETDEWEB)

    Sanguinetti, H.; Oumarou, J. (Cominak, Arlit (Republique du Niger)); Chantret, F. (COGEMA, Chatillon-sous-Bagneux (France))

    1982-03-08

    Uranium rich accumulations in Akouta's ore body occur in bottom set layers of sandstone in which accumulated preferentially plant debris which were submitted to early pyritisation. These reducing beds in aquiferous sandstone shaped locally the redox front line and are a great help in checking the mineralisation for mining geologists.

  20. Mechanism of Suppressing ASR Using Ground Reactive Sandstone Powders instead of Cement

    Institute of Scientific and Technical Information of China (English)

    LI Yang; HE Zhen; HU Shuguang

    2015-01-01

    In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction (ASR), and to identify the mechanism of suppressing ASR by this powders, mortar and paste containing reactive sandstone powders of four replacement levels ranging from 10wt% to 40wt% and four specific surfaces areas ranging from 210 m2/kg to 860 m2/kg were studied. The experimental results showed that incorporation of 40wt%reactive sandstone powders could suppress ASR effectively except for mortar containing reactive sandstone powders with specific surface area of 610 m2/kg, which disagreed with the most results reported that the higher reactive powder specific surface area, the smaller ASR expansion. By means of flame photometry, Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TG), the mechanism of reactive sandstone powders on reducing or suppressing ASR was soluble alkalis type of reactive sandstone powders and the competition of liberating and bonding alkali of cement paste containing reactive sandstone powders,when the ability of alkali bonding was greater than the ability of alkali liberation, ASR caused by reactive sandstone was supressed effectively.

  1. Research on diagenesis of the sandstone-type uranium deposits in Dongsheng area, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Synthetic methods of thin section petrography, scanning electron microscope, electron microprobe, energy spectrum analysis, cathodoluminescence, isotopic analysis and temperature measuring for fluid inclusions were used in analyzing sandstone samples collected from the Zhiluo Formation in order to fully understand the diagenesis evolution and the mineralizing response as well as the genesis of the uranium-bearing sandstone in Dongsheng area. The result shows that (1) the sandstone include lithic silicarenite, feldspathic litharenite and litharenite; (2) the authigenic minerals include clay minerals, carbonate minerals, siliceous and ferric minerals; (3) the physical property of sandstone is obviously controlled by diagenesis; and (4) the sandstone with favorable physical property is propitious to migration and storage of ore-forming fluid, and finally, forming the ore deposit. The sandstone of the Zhiluo Formation had undergone the early diagenetic stage (periods A and B) and the epidiagenetic stage. The evolution of diagenetic environment is in the order of acidic oxidation, alkalescent deoxidization, acidity to transitional environment of oxidation-deoxidization and acidity-alkalescence. The uranium exists in forms of pre-enrichment uranyl ion, active uranyl ion, dispersive adsorptive uranium and uranium mineral, respectively. In addition, the authors also hold that the formation of the sandstone-type uranium is not only related to the oxidation-deoxidization environment, but also closely related to the acidic-alkaline transitional environment, which are propitious to uranium mineralization in sandstone.

  2. The Bentheim Sandstone: Geology, petrophysics, varieties and it's use as dimension stone

    NARCIS (Netherlands)

    Dubelaar, C.W.; Nijland, T.G.

    2014-01-01

    The shallow-marine Bentheim Sandstone was deposited in one of the NW-SE trending basins north of the London-Brabant and Rhenish massifs during the Valanginian (Early Cretaceous). The Bentheim Sandstone forms an important reservoir rock for petroleum, but has also proven itself as a very durable natu

  3. The sandstone's chromatic alteration of the florentine cultural heritage

    Science.gov (United States)

    Vettori, S.; Pecchioni, E.; Cantisani, E.; Ricci, M.; Fratini, F.; Garzonio, C. A.

    2012-04-01

    Pietra Serena is one of the materials more used in Florentine architecture. It is a sandstone that outcrops in the hills north of the city in the municipality of Fiesole and it has been employed mainly for ornamental purposes. This litotype belongs to the the Macigno Formation (Oligocene Upper- Miocene Lower) which consists of beds of turbiditic sandstones separated by pelitic levels which are the finest components of each single turbidity layer. Petrographically, Pietra Serena can be defined as a medium-coarse-grained greywacke made of quartz, feldspars, micas, fragments of metamorphic and magmatic rocks. The clayey matrix is quite abundant, mainly composed by illite, kaolinite and chlorite-vermiculite (present only in some quarries). It is well known that the processes of decay of the sandstones are related to the type of matrix, the amount of cement, the kind of clay minerals and to the pore size distribution, which lead to water infiltrations, swelling of the clay minerals, separation of the clayey matrix, with resulting exfoliation and peeling of the stone artefacts. Pietra Serena has a bluish-grey colour in fresh cut, but many times it is easily oxidized acquiring an ochraceous-reddish brown colour on buildings. Such changes in colour, appear to be due in part to the oxidation of iron, proceeding very quickly from the surface to the inside, though the cohesion is not affected. It is possible to hypothesize that the chromatic changes not necessarily involve a progressive state of alteration of the artefact, but they may often to represents a natural patina acquired with the time. Nevertheless it is necessary to remember that the oxidized layer and its hardness could also be the result of treatments performed in the past. In Florence, several monuments and buildings are affected by such phenomenon, in particular it is possible to note an intense and diffuse reddish colouring on the Pietra Serena utilized for columns and for façade's decorations. In this work

  4. Age, sedimentary environments, and other aspects of sandstone and related host rocks for uranium deposits

    International Nuclear Information System (INIS)

    Project II of the Uranium Geology Working Group was assigned to the study of sedimentary basins and sandstone - type uranium deposits. About 40% of the worlds's uranium resources are contained in sandstone-type deposits, which has led to extensive research. The research was carried out mainly by correspondence, and the results reported by 21 geologists from 10 nations are summarized in this report. It investigated five topics dealing with important aspects of the geology of uranium ores in sandstone host formations: age of host rock; partitioning of uranium between continental and marine sediments; latitude limitation on formation of sandstone deposits; effect of rock formation dip on sandstone ores; usefulness of stable isotope and fluid inclusion studies. The results of studies on these subjects form part of a wider programme of the Working Group, whose final results will be presented at the 27th International Geological Congress in Moscow in 1984

  5. Laboratory Observation and Micromechanics-Based Modelling of Sandstone on Different Scales

    Science.gov (United States)

    Li, Liming; Larsen, Idar; Holt, Rune M.

    2015-07-01

    The mechanical properties of sandstone are, to a large extent, controlled by its microstructure. When sandstone is loaded, the stress conditions and stress history can influence the sandstone in terms of the deformation parameters, strength parameters, failure modes, as well as acoustic properties and other petrophysical parameters. In this paper, we show how we may use a discrete element model to compute the mechanical behaviour based on the microstructure of the rock, as obtained from micro-computed tomography. The model is calibrated with triaxial test data obtained with three different sandstones. The key element in the model is a contact law, attempting to capture deformation and failure at the level of the grain scale. A micromechanics-based core-scale model was also suggested using the same contact law but without explicitly mimicking the rock microstructure. The simulation results from both the microscale model and the macroscale model were in reasonably good agreement with the laboratory measurements on sandstone specimens.

  6. Lithostratigraphical subdivision of the Sherwood Sandstone Group (Triassic) of the northeastern part of the Carlisle Basin, Cumbria and Dumfries and Galloway, UK

    OpenAIRE

    Holliday, D.W.; Jones, N. S.; McMillan, Andrew

    2008-01-01

    Two formations, the St Bees Sandstone and Kirklinton Sandstone, have been mapped in the past within the Triassic Sherwood Sandstone Group of the eastern part of the Carlisle Basin, Cumbria, and adjacent parts of Dumfries and Galloway, UK. However, previous workers have found considerable difficulty in consistently identifying, defining and mapping the Kirklinton Sandstone Formation. The principal lithological change within the Sherwood Sandstone Group is between mainly fine-grained sandstones...

  7. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Member since the last list of Member States was issued (INFCIRC/2/Rev.59) is the Islamic Republic of Mauritania, which deposited the instrument of acceptance of the Statute on 23 November 2004. The Attachment hereto shows the dates on which the present 138 Member States became Members

  8. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Member since the last list of Member States was issued (INFCIRC/2/Rev.67) is Cambodia which deposited its Instrument of Acceptance of the Statute on 23 November 2009. The Attachment hereto shows the dates on which the present 151 Member States became Members

  9. Characterization of the Lower Cambrian sandstone aquifer in the Swedish Baltic Sea area - assessment regarding its potential suitability for storage of CO2

    Science.gov (United States)

    Erlström, M.; Sivhed, U.

    2012-04-01

    In the Baltic region the Cambrian sandstone is considered to have great economic value concerning its aquifer and reservoir properties. Its potential as petroleum reservoir is well known, especially from the Polish, Lithuanian and Russian sectors of the Baltic Sea where oil and gas has been found in anticline traps in the sandstone sequence. Offshore exploration in the Swedish sector has so far not encountered any significant findings of oil and gas. However, the extensive exploration has generated data, which is now being used for assessing the overall properties regarding suitability for storage of CO2. The Swedish primary industry has a great interest in finding potential sites for storage of CO2. A suitable site in the Baltic Sea would be a most favourable alternative in comparison to more remote alternatives such as deep saline aquifers in the North Sea. The Lower Cambrian is in the Swedish sector of the Baltic Sea composed of three main sandstone units varying in thickness between 5 and 50 m occurring within an up to 250 m thick Cambrian sequence dominated by fine-grained terriclastic sediments. The limit of Lower Palaeozoic sequence in the Baltic area is today defined by erosional truncation because of the gently dipping Lower Palaeozoic sequence. To the north and northwest, the limit is found in the Pre-Quaternary, whereas the erosional limit is deeply buried beneath Permian and Mesozoic sediments to the south. Here the Lower Palaeozoic limit is buried to depths reaching more than 2 km. The Cambrian sequence in the distal parts of the Swedish sector occurs at depths of c. 1300 m while it constitutes the bedrock surface in a narrow zone trending from Öland to the north of of Gotland. Sandstone beds constitute 40-60% of the total Cambrian sequence. The main sandstone units have a regional distribution of several thousands of square kilometres. The up to 50 m thick Faludden sandstone member exhibits the best reservoir properties including porosities in the

  10. Diagenesis and fluid flow in the San Juan Basin, New Mexico - regional zonation in the mineralogy and stable isotope composition of clay minerals in sandstone.

    Science.gov (United States)

    Whitney, G.; Northrop, H.R.

    1987-01-01

    The Westwater Canyon Member of the Upper Jurassic Morrison Formation is a relatively homogeneous, hydrologically continuous 100-m-thick sequence of massive fluvial sandstone, bounded above and below by relatively heterogeneous, hydrologically discontinuous units and has served as a primary conduit for fluids within this stratigraphic interval. Patterns of mineral-fluid reactions suggest a basinwide hydrologic regime in which warm, evolved fluids migrated up-dip from the center of the basin under the influence of a regional hydraulic head. -from Authors

  11. Polymer flood projects in sandstone reservoir of Noharkatiya

    Energy Technology Data Exchange (ETDEWEB)

    Borah, N.M.; Talukdar, B.N.

    1984-07-01

    A polymer flooding project, initiated in December 1975, based on results of reservoir engineering studies including 3-D, 3-P numerical simulation, is currently in progress in an Oligocene sandstone reservoir of the Nahorkatiya Oilfield in Upper Assam. As against an estimated primary depletion RF of 21%, the anticipated RF under polymer flooding is 38%, of which to date 27% of oil-in-place has been produced. Field experience suggests that polymer (Pusher 500) injectively is substantially lower than fresh water injectivity. A scrutiny of reservoir performance confirms significant improvements due to polymer flooding. Tracers are being used to monitor the advancement of the polymer flood front. No significant breakthrough of polymer treated water has yet been reported with a cumulative injection of about 11% of the reservoir hydrocarbon pore volume.

  12. Biological transformation of phenols in a sandstone aquifer

    DEFF Research Database (Denmark)

    Broholm, M.; Arvin, E.

    1997-01-01

    Ammonia liquor with very high concentrations of phenols is known to have leaked into the subsurface at a former coal carbonization plant in the UK. High concentrations of ammonium has been encountered in the groundwater reservoir at the site. In spite of this no significant concentrations...... of phenols are found in the groundwater. In this study the potential for transformation of the phenols in the sandstone aquifer at the site under aerobic, nitrate enriched and ''unaltered'' (limited nitrate available, ironoxides and sulphate available) is investigated in laboratory microcosms. Preliminary...... results reveal complete transformation of phenol, cresols and 3,4-xylenol under all 3 conditions and of 2,5-xylenol under aerobic conditions and 3,5-xylenol under anoxic conditions. The potential for natural attenuation of the phenols in this aquifer appear very promising....

  13. Wave Dispersion and Attenuation in Partially Saturated Sandstones

    Institute of Scientific and Technical Information of China (English)

    NIE Jian-Xin; YANG Ding-Hui; YANG Hui-Zhu

    2004-01-01

    @@ We investigate the wave dispersion and attenuation in partially water-saturated sandstones based on the improved Biot/squirt (BISQ) model in which the saturation is introduced. Numerical experiments indicate that the phase velocity of the fast P-wave decreases as the saturation increases in the low-frequency range (102-104 Hz), and reaches the minimum at the full-saturation state. The behaviour of the phase velocity varying with the saturation in the high-frequency range (104-106 Hz), however, is opposite to that in the low-frequency range. The peak value of P-wave attenuation increases with increasing saturation, and is the maximum at the fully saturated state. Numerical models and experiments show that the improved BISQ model is better than the traditional Gassmann-Biot model.

  14. Quantifying tight-gas sandstone permeability via critical path analysis

    Science.gov (United States)

    Ghanbarian, Behzad; Torres-Verdín, Carlos; Skaggs, Todd H.

    2016-06-01

    Rock permeability has been actively investigated over the past several decades by the geosciences community. However, its accurate estimation still presents significant technical challenges, particularly in spatially complex rocks. In this short communication, we apply critical path analysis (CPA) to estimate permeability in porous rocks from measured mercury intrusion porosimetry and electrical conductivity data. Theoretical estimations of various CPA-based models are then compared to experimental measurements using eighteen tight-gas sandstones. Except for two of the samples, we find permeability estimations performed with the Skaggs model (assuming pore diameter independent of its length) more accurate than other models, within a factor of two of the measured permeabilities. We discuss some plausible sources of the uncertainties.

  15. Process-dependent residual trapping of CO2 in sandstone

    Science.gov (United States)

    Zuo, Lin; Benson, Sally M.

    2014-04-01

    This paper demonstrates that the nature and extent of residual CO2 trapping depend on the process by which the CO2 phase is introduced into the rock. We compare residual trapping of CO2 in Berea Sandstone by imbibing water into a core containing either exsolved CO2 or CO2 introduced by drainage. X-ray computed tomography measurements are used to map the spatial distribution of CO2 preimbibition and postimbibition. Unlike during drainage where the CO2 distribution is strongly influenced by the heterogeneity of the rock, the distribution of exsolved CO2 is comparatively uniform. Postimbibition, the CO2 distribution retained the essential features for both the exsolved and drainage cases, but twice as much residual trapping is observed for exsolved CO2 even with similar preimbibition gas saturations. Residually trapped exsolved gas also disproportionately reduced water relative permeability. Development of process-dependent parameterization will help better manage subsurface flow processes and unlock benefits from gas exsolution.

  16. Offers for our members

    CERN Multimedia

    Staff Association

    2015-01-01

    Summer is here, enjoy our offers for the aquatic parcs! Walibi : Tickets "Zone terrestre": 21,50 € instead of 27 €. Access to Aqualibi: 5 € instead of 6 € on presentation of your SA member ticket. Free for children (3-11 years old) before 12:00 p.m. Free for children under 3, with limited access to the attractions. Car park free. * * * * * Aquaparc : Day ticket: – Children: 33 CHF instead of 39 CHF – Adults : 33 CHF instead of 49 CHF Bonus! Free for children under 5.

  17. Offers for our members

    CERN Multimedia

    Staff Association

    2016-01-01

    Summer is here, enjoy our offers for the aquatic parcs! Walibi : Tickets "Zone terrestre": 23 € instead of 29 €. Access to Aqualibi: 5 € instead of 6 € on presentation of your SA member ticket. Free for children (3-11 years old) before 12:00 p.m. Free for children under 3, with limited access to the attractions. Car park free. * * * * * Aquaparc : Day ticket: – Children: 33 CHF instead of 39 CHF – Adults : 33 CHF instead of 49 CHF Bonus! Free for children under 5.

  18. Offers for our members

    CERN Multimedia

    Staff Association

    2013-01-01

    Summer is here, enjoy our offers for the aquatic parcs! Walibi : Tickets "Zone terrestre": 21 € instead of 26 €. Access to Aqualibi: 5 € instead of 8 € on presentation of your SA member ticket. Free for children (3-11 years old) before 12 h 00. Free for children under 3, with limited access to the attractions. Car park free. * * * * * Aquaparc : Day ticket: – Children: 30 CHF instead of 39 CHF – Adults : 36 CHF instead of 49 CHF Bonus! Free for children under 5.

  19. Crater morphology in sandstone targets: The MEMIN impact parameter study

    Science.gov (United States)

    Dufresne, Anja; Poelchau, Michael H.; Kenkmann, Thomas; Deutsch, Alex; Hoerth, Tobias; SchńFer, Frank; Thoma, Klaus

    2013-01-01

    Hypervelocity (2.5-7.8 km s-1) impact experiments into sandstone were carried out to investigate the influence of projectile velocity and mass, target pore space saturation, target-projectile density contrast, and target layer orientation on crater size and shape. Crater size increases with increasing projectile velocity and mass as well as with increasing target pore space saturation. Craters in water-saturated porous targets are generally shallower and larger in volume and in diameter than craters from equivalent impacts into dry porous sandstone. Morphometric analyses of the resultant craters, 5-40 cm in diameter, reveal features that are characteristic of all of our experimental craters regardless of impact conditions (I) a large central depression within a fragile, light-colored central part, and (II) an outer spallation zone with areas of incipient spallation. Two different mechanical processes, grain fragmentation and intergranular tensile fracturing, are recorded within these crater morphologies. Zone (I) approximates the shape of the transient crater formed by material compression, displacement, comminution, and excavation flow, whereas (II) is the result of intergranular tensile fracturing and spallation. The transient crater dimensions are reconstructed by fitting quadric parabolas to crater profiles from digital elevation models. The dimensions of this transient and of the final crater show the same trends: both increase in volume with increasing impact energy, and with increasing water saturation of the target pore space. The relative size of the transient crater (in percent of the final crater volume) decreases with increasing projectile mass and velocity, signifying a greater contribution of spallation on the final crater size when projectile mass and velocity are increased.

  20. Ejection behavior characteristics in experimental cratering in sandstone targets

    Science.gov (United States)

    Sommer, Frank; Reiser, Fiona; Dufresne, Anja; Poelchau, Michael H.; Hoerth, Tobias; Deutsch, Alex; Kenkmann, Thomas; Thoma, Klaus

    2013-01-01

    Within the frame of the MEMIN research unit (Multidisciplinary Experimental and Numerical Impact Research Network), impact experiments on sandstone targets were carried out to systematically study the influence of projectile mass, velocity, and target water saturation on the cratering and ejection processes. The projectiles were accelerated with two-stage light-gas guns (Ernst-Mach-Institute) onto fine-grained targets (Seeberger sandstone) with about 23% porosity. Collection of the ejecta on custom-designed catchers allowed determination of particle shape, size distribution, ejection angle, and microstructures. Mapping of the ejecta imprints on the catcher surface enabled linking of the different patterns to ejection stages observed on high-speed videos. The increase in projectile mass from 0.067 to 7.1 g correlates with an increase in the total ejected mass; ejecta angles, however, are similar in range for all experiments. The increase in projectile velocity from 2.5 to 5.1 km s-1 correlates with a total ejecta mass increase as well as in an increase in comminution efficiency, and a widening of the ejecta cone. A higher degree of water saturation of the target yields an increase in total ejecta mass up to 400% with respect to dry targets, higher ejecta velocity, and a steeper cone. These data, in turn, suggest that the reduced impedance contrast between the quartz grains of the target and the pores plays a primary role in the ejecta mass increase, while vaporization of water determines the ejecta behavior concerning ejecta velocity and particle distribution.

  1. Reservoir characterization of Pennsylvanian Sandstone Reservoirs. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.

    1992-09-01

    This annual report describes the progress during the second year of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description and scale-up procedures; (ii) outcrop investigation; (iii) in-fill drilling potential. The first section describes the methods by which a reservoir can be characterized, can be described in three dimensions, and can be scaled up with respect to its properties, appropriate for simulation purposes. The second section describes the progress on investigation of an outcrop. The outcrop is an analog of Bartlesville Sandstone. We have drilled ten wells behind the outcrop and collected extensive log and core data. The cores have been slabbed, photographed and the several plugs have been taken. In addition, minipermeameter is used to measure permeabilities on the core surface at six inch intervals. The plugs have been analyzed for the permeability and porosity values. The variations in property values will be tied to the geological descriptions as well as the subsurface data collected from the Glen Pool field. The third section discusses the application of geostatistical techniques to infer in-fill well locations. The geostatistical technique used is the simulated annealing technique because of its flexibility. One of the important reservoir data is the production data. Use of production data will allow us to define the reservoir continuities, which may in turn, determine the in-fill well locations. The proposed technique allows us to incorporate some of the production data as constraints in the reservoir descriptions. The technique has been validated by comparing the results with numerical simulations.

  2. Microbial Penetration through Nutrient-Saturated Berea Sandstone.

    Science.gov (United States)

    Jenneman, G E; McInerney, M J; Knapp, R M

    1985-08-01

    Penetration times and penetration rates for a motile Bacillus strain growing in nutrient-saturated Berea sandstone cores were determined. The rate of penetration was essentially independent of permeabilities above 100 mdarcys and rapidly declined for permeabilities below 100 mdarcys. It was found that these penetration rates could be grouped into two statistically distinct classes consisting of rates for permeabilities above 100 mdarcys and rates for those below 100 mdarcys. Instantaneous penetration rates were found to be zero order with respect to core length for cores with permeabilities above 100 mdarcys and first order with respect to core length for cores with permeabilities below 100 mdarcys. The maximum observed penetration rate was 0.47 cm . h, and the slowest was 0.06 cm . h; however, these rates may be underestimates of the true penetration rate, since the observed rates included the time required for growth in the flask as well as the core. The relationship of penetration time to the square of the length of the core suggested that cells penetrated high-permeability cores as a band and low-permeability cores in a diffuse fashion. The motile Enterobacter aerogenes strain penetrated Berea sandstone cores three to eight times faster than did the nonmotile Klebsiella pneumoniae strain when cores of comparable length and permeability were used. A penetration mechanism based entirely on motility predicted penetration times that were in agreement with the observed penetration times for motile strains. The fact that nonmotile strains penetrated the cores suggested that filamentous or unrestricted growth, or both, may also be important.

  3. Complete-member Ethnography

    Directory of Open Access Journals (Sweden)

    Hsun-Yu Sharon Chuang

    2015-11-01

    Full Text Available Within the vast array of ethnographic research methodology, complete-member ethnography (CME is one ethnographic inquiry whose methodological development is still in infantile in intercultural communication research. Specifically in this article, the author includes four major sections to understand and to advance CME. First, the author reviews the historical development of CME, and realizes epistemological intimacy as the core of CME and as how researchers’ complete-memberships may be established. Second, the author explains the concept and practice of epistemological intimacy in extant literature. Third, the author advances the concept of epistemological intimacy to identify and explain five contextual factors that influence a complete-member ethnographer’s complete-membership to his or her research community. The five factors include historicity of identity, institutional memory, situational (intersubjectivity, consensual membership, and symbolic codes. In order to elucidate that said factors are essentially interrelated, the author supplements the five factors with her conceptualizations of selfhood/identity. In the end, the author discusses three potential contributions of how CME can advance critical communication research, which pertain to (a praxis and reflexivity, (b challenging struggles and inequalities in power and privilege, and (c promote hopeful social justice from within.

  4. Quartz cementation mechanisms between adjacent sandstone and shale in Middle Cambrian, West Lithuania

    Science.gov (United States)

    Zhou, Lingli; Friis, Henrik

    2013-04-01

    Quartz is an important cementing material in siliciclastic sandstones that can reduce porosity and permeability severely. For efficiently predicting and extrapolating petrophysical properties such as porosity and permeability, the controls on the occurrence and the degree of quartz cementation need to be better understood. Because it is generally difficult to identify specific sources for quartz cement, many models attempting to explain quartz cementation conclude that external sources of silica are needed to explain the observed quantity of quartz cement, such as the mass transfer between sandstone and shale. Cambrian sandstones in Lithuania have abundant quartz cement which has significant effect on reservoir properties. The detrital quartz grains have been dissolved extensively along the shale-quartz contacts zones, making it a natural laboratory to study the influence of mass transfer between sandstone and shale to quartz cementation on petrophysical properties and reservoir quality. Our Cambrian shale samples in west Lithuania are mainly silty shale or siltstone (sample locations vary from 330 to 2090 m of burial depth). They are composed of quartz, clay and traces of feldspars, sericite, calcite, and pyrite. The clay minerals are mainly illite, with variable content of kaolinite and traces of chlorite. In the sandstone lamina, authigenic illite occurs as pore-filling cement which was composed of fibrous illite; pore-filling kaolinite is generally well crystallized and occurs as hexagonal plates arranged in booklets; quartz overgrowth are obvious in these sandstone laminas, especially in the contact zones between sandstone and shale. Dolomite and pyrite cementation are also present in some sandstone laminas but with few quartz overgrowth. Depositional facies and architecture played an important role in the precipitation of silica. Three different possible sources are distinguished for the quartz overgrowths in the intercalated sandstones: 1) Pressure

  5. Quantitative studies of hydrocarbon loss of the Silurian bitumen sandstone in the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The evolution of Tarim Basin experienced several tectonic movements,of which Caledonian movement caused a serious damage to reservoirs of Silurian. The earlier reservoirs size and the later hydrocarbon loss are two key factors to exploration prospect of Silurian. On the basis of net thickness of bituminous sandstone and recovery coefficient of crude oil converting to bitumen,the scale of the hydrocarbon loss of palaeo-accumulation in bitumen sandstone of Silurian was calculated (86.30×108t). The deter-mination of net thickness of bitumen sandstone was completed mainly by several methods,such as physical property demarcation,observing lithology,grains with oil inclusion (GOI) technology,and quantitative grains fluorescence (QGF) technology. The samples of black sandstone and white sand-stone were collected and compared by means of the methods mentioned above. The results showed that there was little hydrocarbon,or none,in the white sandstone. The recovery coefficient was ob-tained by the analyses of plentiful physical parameters of crude oil and bitumen sandstone,based on the hypothesis that nonhydrocarbon compounds and bitumen were invariable in the process of bitu-men forming. The calculated result,which is more scientific and actual,indicates the exploration pros-pect is more promising in Silurian of the Tarim Basin.

  6. Effects of Pisha sandstone content on solute transport in a sandy soil.

    Science.gov (United States)

    Zhen, Qing; Zheng, Jiyong; He, Honghua; Han, Fengpeng; Zhang, Xingchang

    2016-02-01

    In sandy soil, water, nutrients and even pollutants are easily leaching to deeper layers. The objective of this study was to assess the effects of Pisha sandstone on soil solute transport in a sandy soil. The miscible displacement technique was used to obtain breakthrough curves (BTCs) of Br(-) as an inert non-adsorbed tracer and Na(+) as an adsorbed tracer. The incorporation of Pisha sandstone into sandy soil was able to prevent the early breakthrough of both tracers by decreasing the saturated hydraulic conductivity compared to the controlled sandy soil column, and the impeding effects increased with Pisha sandstone content. The BTCs of Br(-) were accurately described by both the convection-dispersion equation (CDE) and the two-region model (T-R), and the T-R model fitted the experimental data slightly better than the CDE. The two-site nonequilibrium model (T-S) accurately fit the Na(+) transport data. Pisha sandstone impeded the breakthrough of Na(+) not only by decreasing the saturated hydraulic conductivity but also by increasing the adsorption capacity of the soil. The measured CEC values of Pisha sandstone were up to 11 times larger than those of the sandy soil. The retardation factors (R) determined by the T-S model increased with increasing Pisha sandstone content, and the partition coefficient (K(d)) showed a similar trend to R. According to the results of this study, Pisha sandstone can successfully impede solute transport in a sandy soil column.

  7. Offers for our members

    CERN Multimedia

    Staff Association

    2013-01-01

    The Courir shops propose the following offer: 15% discount on all articles (not on sales) in the Courir shops (Val Thoiry, Annemasse and Neydens) and 5% discount on sales upon presentation of your Staff Association membership card and an identity card before payment. Summer is here, enjoy our offers for the aquatic parcs! Walibi : Tickets "Zone terrestre": 21 € instead of 26 €. Access to Aqualibi: 5 € instead of 8 € on presentation of your SA member ticket. Free for children (3-11 years old) before 12 h 00. Free for children under 3, with limited access to the attractions. Car park free. * * * * * Aquaparc : Day ticket: – Children: 30 CHF instead of 39 CHF – Adults : 36 CHF instead of 49 CHF Bonus! Free for children under 5.

  8. Offers for our members

    CERN Multimedia

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    2013-01-01

    La banque LCL propose aux membres de l’Association du personnel les avantages suivants : – Un barème Privilège sur le Prêt immobilier – Des avantages tarifaires sur l’épargne, notamment l’assurance-vie. – Un taux préférentiel de prêt à la consommation. En outre, jusqu’au 30 septembre 2013, elle offre 50€ à tous les nouveaux clients, membres de l'Association du personnel. Summer is here, enjoy our offers for the aquatic parcs! Tickets "Zone terrestre" : 21 € instead of de 26 €. Access to Aqualibi : 5 euros instead of 8 euros on presentation of your SA member ticket. Free for children (3-11 years old) before 12 h 00. Free for children under 3, with limited access to the attractions. Free car park. * * * * * * * Full day ticket: – Children : 30 CHF instead of 39 CHF &...

  9. Offers for our members

    CERN Multimedia

    Staff Association

    2013-01-01

    The warm weather arrives, it's time to take advantage of our offers Walibi and Aquapark! Walibi : Tickets "Zone terrestre": 21 € instead of 26 € Access to Aqualibi: 5 € instead of 8 € on presentation of your SA member ticket. Free for children (3-11 years old) before 12 h 00. Free for children under 3, with limited access to the attractions. Car park free. * * * * * Aquaparc : Half-day ticket (5 hours): – Children: 26 CHF instead of 35 CHF – Adults : 32 CHF instead of 43 CHF Day ticket: – Children: 30 CHF instead of 39 CHF – Adults : 36 CHF instead of 49 CHF Free for children under 5.

  10. Anaerobic abiotic transformations of cis-1,2-dichloroethene in fractured sandstone.

    Science.gov (United States)

    Darlington, Ramona; Lehmicke, Leo G; Andrachek, Richard G; Freedman, David L

    2013-02-01

    A fractured sandstone aquifer at an industrial site is contaminated with trichloroethene to depths greater than 244 m. Field data indicate that trichloroethene is undergoing reduction to cis-1,2-dichloroethene (cDCE); vinyl chloride and ethene are present at much lower concentrations. Transformation of cDCE by pathways other than reductive dechlorination (abiotic and/or biotic) is of interest. Pyrite, which has been linked to abiotic transformation of chlorinated ethenes, is present at varying levels in the sandstone. To evaluate the possible role of pyrite in transforming cDCE, microcosms were prepared with groundwater, ~40 mg L(-1) cDCE+[(14)C]cDCE, and crushed solids (pure pyrite, pyrite-rich sandstone, or typical sandstone). During 120 d of incubation, the highest level of cDCE transformation occurred with typical sandstone (11-14% (14)CO(2), 1-3% (14)C-soluble products), followed by pyrite-rich sandstone (2-4% (14)CO(2), 1% (14)C-soluble products) and even lesser amounts with pure pyrite. These results indicate pyrite is not likely the mineral involved in transforming cDCE. A separate experiment using only typical sandstone compared the rate of cDCE transformation in non-sterilized, autoclaved, and propylene-oxide sterilized treatments, with pseudo-first order rate constants of 8.7, 5.4, and 1.0 yr(-1), respectively; however, transformation stopped after several months of incubation. Autoclaving increased the volume of pores, adsorption pore diameter, and surface area in comparison to non-sterilized typical sandstone. Nevertheless, autoclaving was less disruptive than chemical sterilization. The results provide definitive experimental evidence that cDCE undergoes anaerobic abiotic and biotic transformation in typical sandstone, with formation of CO(2) and soluble products.

  11. Facies architecture of the Bluejacket Sandstone in the Eufaula Lake area, Oklahoma: Implications for the reservoir characterization of the Bartlesville Sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Liangmiao; Yang, Kexian [Univ. of Tulsa, OK (United States)

    1997-08-01

    Outcrop studies of the Bluejacket Sandstone (Middle Pennsylvanian) provide significant insights to reservoir architecture of the subsurface equivalent Bartlesville Sandstone. Quarry walls and road cuts in the Lake Eufaula area offer excellent exposures for detailed facies architectural investigations using high-precision surveying, photo mosaics. Directional minipermeameter measurements are being conducted. Subsurface studies include conventional logs, borehole image log, and core data. Reservoir architectures are reconstructed in four hierarchical levels: multi-storey sandstone, i.e. discrete genetic intervals; individual discrete genetic interval; facies within a discrete genetic interval; and lateral accretion bar deposits. In both outcrop and subsurface, the Bluejacket (Bartlesville) Sandstone comprises two distinctive architectures: a lower braided fluvial and an upper meandering fluvial. Braided fluvial deposits are typically 30 to 80 ft thick, and are laterally persistent filling an incised valley wider than the largest producing fields. The lower contact is irregular with local relief of 50 ft. The braided-fluvial deposits consist of 100-400-ft wide, 5-15-ft thick channel-fill elements. Each channel-fill interval is limited laterally by an erosional contact or overbank deposits, and is separated vertically by discontinuous mudstones or highly concentrated mudstone interclast lag conglomerates. Low-angle parallel-stratified or trough cross-stratified medium- to coarse-grained sandstones volumetrically dominate. This section has a blocky well log profile. Meandering fluvial deposits are typically 100 to 150 ft thick and comprise multiple discrete genetic intervals.

  12. The Members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 132 Member States of the Agency as of 1 June 2001. The new Members since the last issue of the list (INFCIRC/2/53) are Central African Republic and Azerbaijan. The dates on which the present 132 Member States became Members are given in an Attachment. It also shows the States whose application for membership of the Agency has been approved by the General Conference but which has not yet deposited an instrument of acceptance of the Statute

  13. Weathering behavior investigations and treatment of Kom Ombo temple sandstone, Egypt - Based on their sedimentological and petrogaphical information

    Science.gov (United States)

    Temraz, Mostafa Gouda; Khallaf, Mohamed K.

    2016-01-01

    The Temple of Kom Ombo is a huge ancient Egyptian temple in Upper Egypt. It was built by Ptolemy VI Philometor (180-145 BC) and added to by subsequent Ptolemys. The structure of the temple is built of local sandstone attributed to the Quseir Formation of "Nubian Sandstone" group at Gebel el-Silsila. Sandstone samples from Kom Ombo temple were taken to verify the source rock of the quarried material. Optical Polarizing Microscope (OPM) and Scanning Electron Microscope (SEM) were used to determine the microstructure and physical properties of the sandstone. X-Ray diffraction (XRD) was carried out for the Sandstone samples to identify its mineralogical composition. The sandstone samples were treated with six polymeric products to determine changes in their physical and mechanical properties after penetration, consolidation of polymers within them. This sandstone is composed mainly of three quartz arenite microfacies (feldspathic, sublithic and calcareous) that are interpreted to have been deposited in fluvial to fluvial-marine environment. Silane polymers is showing a good penetration and filling pores between grains and recommended for treatment and conservation of the sandstone. Acrylic polymer shows random penetration of polymer and formation of a film of polymer on the surface of sandstone. Silo11 gave the best result in consolidation of sandstone samples then primal AC33. Wacker BS29 gave the best result in isolating process of sandstone samples, then wacker BS 290.

  14. Fluid migration through sandstone fractures in Gale Crater, Mars

    Science.gov (United States)

    Yen, Albert; Blake, David; Bristow, Thomas; Chipera, Steve; Downs, Robert; Gellert, Ralf; Grotzinger, John P.; Ming, Doug; Morris, Richard; Morrison, Shaunna; Rampe, Liz; Thompson, Lucy; Treiman, Allan; Vaniman, David; MSL Science Team

    2016-10-01

    The Curiosity Mars rover encountered numerous occurrences of light-toned fractures in lithified sediments along its traverse in Gale Crater. These alteration zones can be traced for tens of meters across the landscape and are generally less than a meter in width. Two of these features were investigated in detail by the rover instruments, including drilling to acquire samples both within and immediately outside the lighter-toned areas.The chemical composition established by the Alpha Particle X-ray Spectrometer (APXS) on the arm of the rover shows that the alteration zones are significantly enhanced in silica (40% increase) and sulfur (factor of ~5) relative to the surrounding rocks. Concentrations of Fe, Mg, Al, Mn, Ni and Zn are reduced by a factor of two or more. The correlation between Ca and SO3 indicates the presence of Ca-sulfates, but with up to 15% SO3 (and only 6% to 9% CaO) in the APXS data, the presence of Mg and Fe sulfates in the altered fractures is likely.The Chemistry and Mineralogy (CheMin) X-ray diffraction instrument analyzed the drill fines and found mostly plagioclase feldspar, pyroxenes and magnetite in the unaltered sandstones. X-ray amorphous material and minor hematite and Ca-sulfates are also present. Samples from the alteration zones, however, show a factor of two decrease in the pyroxene to feldspar ratio, abundant Ca-sulfates in various hydration states, and a majority fraction of amorphous material rich in silica and mixed-cation sulfates.The direct comparison of samples within and adjacent to the light toned fractures indicates an alteration process involving the dissolution of pyroxenes and removal of metal cations. The mobility of Al and the likely presence of Fe-sulfates suggest alteration in an acidic environment, but additional moderate pH episodes cannot be ruled out. These features post-date the sandstone lithification and are among the youngest fluid events studied thus far in Gale Crater.

  15. Temperature dependent elasticity and damping in dehydrated sandstone

    Science.gov (United States)

    Darling, T. W.; Struble, W.

    2013-12-01

    Work reported previously at this conference, outlining our observation of anomalously large elastic softening and damping in dehydrated Berea sandstone at elevated temperatures, has been analysed to study shear and compressional effects separately. Modeling of the sample using COMSOL software was necessary to identify modes, as the vibration spectrum of the sample is poorly approximated by a uniform isotropic solid. The first torsional mode of our evacuated, dry, core softens at nearly twice the rate of Young's modulus modes (bending and compressional) and is also damped nearly twice as strongly as temperature increases. We consider two possible models for explaining this behavior, based on the assumption that the mechanical properties of the sandstone are dominated by the framework of quartz grains and polycrystalline cementation, neglecting initially the effects of clay and feldspar inclusions. The 20cm x 2.54cm diameter core is dry such that the pressure of water vapor in the experiment chamber is below 1e-6 Torr at 70C, suggesting that surface water beyond a small number of monolayers is negligible. Our models consider (1) enhanced sliding of grain boundaries in the cementation at elevated temperature and reduced internal water content, and (2) strain microcracking of the cementatioin at low water content due to anisotropic expansion in the quartz grains. In model (1) interfaces parallel to polyhedral grain surfaces were placed in the cement bonds and assigned frictional properties. Model (2) has not yet been implemented. The overall elasticity of a 3-D several-grain model network was determined by modeling quasistatic loading and measuring displacements. Initial results with a small number of grains/bonds suggests that only the first model provides softening and damping for all the modes, however the details of the effects of defect motioin at individual interfaces as the source for the frictional properties is still being evaluated. Nonlinear effects are

  16. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Member since the last list of Member States was issued (INFCIRC/2/Rev.74) is Swaziland, which deposited its instrument of acceptance of the Statute on 15 February 2013. The Attachment hereto shows the dates on which the present 159 Member States deposited instruments of ratification or acceptance of the Statute with the depositary Government

  17. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Member since the last list of Member States was issued (INFCIRC/2/Rev.70) is Papua New Guinea, which deposited its instrument of acceptance of the Statute on 4 April 2012. The Attachment hereto shows the dates on which the present 154 Member States deposited instruments of ratification or acceptance of the Statute with the depositary Government

  18. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Member since the last list of Member States was issued (INFCIRC/2/Rev.73) is Trinidad and Tobago, which deposited its instrument of acceptance of the Statute on 9 November 2012. The Attachment hereto shows the dates on which the present 158 Member States deposited instruments of ratification or acceptance of the Statute with the depositary Government

  19. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Member since the last list of Member States was issued (INFCIRC/2/Rev.71) is Rwanda, which deposited its instrument of acceptance of the Statute on 4 September 2012. The Attachment hereto shows the dates on which the present 155 Member States deposited instruments of ratification or acceptance of the Statute with the depositary Government

  20. Survival and growth of hardwoods in brown versus gray sandstone on a surface mine in West Virginia.

    Science.gov (United States)

    Emerson, P; Skousen, J; Ziemkiewicz, P

    2009-01-01

    Surface mining in West Virginia removes the eastern deciduous forest and reclaiming the mined land to a productive forest must consider soil depth, soil physical and chemical properties, soil compaction, ground cover competition, and tree species selection. Our objective was to evaluate tree survival and growth in weathered brown sandstone and in unweathered gray sandstone. Brown and gray sandstone are often substituted when insufficient native topsoil is available for replacement. Three 2.8-ha plots were constructed with either 1.5 or 1.2 m of brown sandstone, or 1.5 m of gray sandstone at the surface. Half of each plot was compacted with a large dozer. Percent fines (sandstone and 34% in gray. Brown sandstone's pH was 5.1, while gray sandstone's pH was around 8.0. In March 2005, 2-yr-old seedlings of 11 hardwood species were planted. After 3 yr, tree survival was 86% on 1.5-m gray sandstone, 67% on 1.5-m brown sandstone, and 82% on 1.2-m brown sandstone. Survival was 78% on noncompacted and 79% on compacted areas. Average volume of all trees (height x diameter(2)) was significantly greater on brown sandstone (218 cm(3)) than gray sandstone (45 cm(3)) after 3 yr. Black locust (Robinia pseudoacacia L.) had the highest survival (100%) and significantly greater volume (792 cm(3)) than all other tree species. Survival of the other 10 species varied between 65% for tulip poplar (Liriodendron tulipifera L.) and 92% for redbud (Cercis canadensis L.), and volume varied between 36 cm(3) for white pine (Pinus strobes L.) and 175 cm(3) for tulip poplar. After 3 yr, brown sandstone appears to be a better topsoil material due to the much greater growth of trees, but tree growth over time as these topsoils weather will determine whether these trends continue.

  1. Middle Micoene sandstone reservoirs of the Penal/Barrackpore field

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, B.L. (Trinidad and Tobago Marine Petroleum Co. Ltd., Pointe-a-Pierre (Trinidad))

    1991-03-01

    The Penal/Barrackpore field was discovered in 1938 and is located in the southern subbasin of onshore Trinidad. The accumulation is one of a series of northeast-southwest trending en echelon middle Miocene anticlinal structures that was later accentuated by late Pliocene transpressional folding. Relative movement of the South American and Caribbean plates climaxed in the middle Miocene compressive tectonic event and produced an imbricate pattern of southward-facing basement-involved thrusts. Further compressive interaction between the plates in the late Pliocene produced a transpressive tectonic episode forming northwest-southeast oriented transcurrent faults, tear faults, basement thrust faults, lystric normal faults, and detached simple folds with infrequent diapiric cores. The middle Miocene Herrera and Karamat turbiditic sandstones are the primary reservoir rock in the subsurface anticline of the Penal/Barrackpore field. These turbidites were sourced from the north and deposited within the marls and clays of the Cipero Formation. Miocene and Pliocene deltaics and turbidites succeed the Cipero Formation vertically, lapping into preexisting Miocene highs. The late Pliocene transpression also coincides with the onset of oil migration along faults, diapirs, and unconformities from the Cretaceous Naparima Hill source. The Lengua Formation and the upper Forest clays are considered effective seals. Hydrocarbon trapping is structurally and stratigraphically controlled, with structure being the dominant trapping mechanism. Ultimate recoverable reserves for the field are estimated at 127.9 MMBo and 628.8 bcf. The field is presently owned and operated by the Trinidad and Tobago Oil Company Limited (TRINTOC).

  2. Mineral changes in cement-sandstone matrices induced by biocementation

    Energy Technology Data Exchange (ETDEWEB)

    Verba, C. [National Energy Technology Lab. (NETL), Albany, OR (United States); Thurber, A. R. [Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Sciences; Alleau, Y. [Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Sciences; Koley, D. [Oregon State Univ., Corvallis, OR (United States). College of Science; Colwell, F. [Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Sciences; Torres, M. E. [Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Sciences

    2016-04-01

    Prevention of wellbore CO2 leakage is a critical component of any successful carbon capture, utilization, and storage program. Sporosarcina pasteurii is a bacterium that has demonstrated the potential ability to seal a compromised wellbore through the enzymatic precipitation of CaCO3. In this paper, we investigate the growth of S. pasteurii in a synthetic brine that mimics the Illinois Basin and on Mt. Simon sandstone encased in Class H Portland cement under high pressure and supercritical CO2 (PCO2) conditions. The bacterium grew optimum at 30 °C compared to 40 °C under ambient and high pressure (10 MPa) conditions; and growth was comparable in experiments at high PCO2. Sporosarcina pasteurii actively induced the biomineralization of CaCO3 polymorphs and MgCa(CO3)2 in both ambient and high pressure conditions as observed in electron microscopy. In contrast, abiotic (non-biological) samples exposed to CO2 resulted in the formation of surficial vaterite and calcite. Finally, the ability of S. pasteurii to grow under subsurface conditions may be a promising mechanism to enhance wellbore integrity.

  3. Hydrochemical evolution of the East Midlands Triassic sandstone aquifer, England

    Science.gov (United States)

    Edmunds, W. M.; Bath, A. H.; Miles, D. L.

    1982-11-01

    A detailed hydrogeochemical interpretation has been made of the red-bed, Sherwood Sandstone (Triassic) aquifer of the East Midlands of England, on which a radiocarbon model has been used to establish a chronology of groundwaters along the flow line. Groundwater evolution is dominated by carbonate and sulphate mineral solution and precipitation and by redox reactions; cation exchange reactions are negligible and the hydrogeochemistry has evolved in the absence of residual saline water. Three distinct zones are recognised: I. Recent groundwater (mainly 10 4 y, reducing conditions, approach to isotopic and chemical equilibrium in the carbonate system, dominance of gypsum dissolution. The minor and trace element variation can be interpreted in relation to the principal geochemical reactions and recharge history. Na +, Cl -, F - and B are controlled by atmospheric inputs. Sr 2+ and Mn 2+ trends can be explained by carbonate and sulphate mineral dissolution; Ba 2+ is derived from carbonates but controlled by barite equilibrium. Fe, SO 42-, NO 3- and U are strongly influenced by redox reactions. The concentrations of transition metals and other elements remain very low. Only Li + and K + are considered to represent additions by reaction of silicate minerals. The extent of direct anthropogenic influence is probably limited to enhanced SO 4-, NO 32- and possibly Cu, Zn and Pb in Zone I.

  4. Rice Lake National Wildlife Refuge : Sandstone Unit : Mille Lacs National Wildlife Refuge : Fiscal year 2002

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Rice Lake (including the Sandstone Unit) and Mille Lacs National Wildlife Refuges outlines Refuge accomplishments during the 2002...

  5. Middle Ordovician brachiopods from the Stairway Sandstone, Amadeus Basin, central Australia

    DEFF Research Database (Denmark)

    Jakobsen, Kristian Grube; Brock, Glenn A.; Nielsen, Arne Thorshøj;

    2014-01-01

    Middle Ordovician brachiopod faunas from the Amadeus Basin, central Australia are poorly known. The Darriwilian Stairway Sandstone was sampled stratigraphically for macrofossils in order to provide new information on marine benthic diversity in this clastic-dominated, shallow-water palaeoenvironm......Middle Ordovician brachiopod faunas from the Amadeus Basin, central Australia are poorly known. The Darriwilian Stairway Sandstone was sampled stratigraphically for macrofossils in order to provide new information on marine benthic diversity in this clastic-dominated, shallow......-water palaeoenvironment along the margin of northeastern Gondwana. The brachiopods from the Stairway Sandstone are of low diversity and represent ca 9% of the entire shelly fauna. Five brachiopod taxa are described from the Stairway Sandstone; all are endemic to the Amadeus Basin at species level. Two new species...

  6. Rice Lake National Wildlife Refuge : Mille Lacs National Wildlife Refuge : Sandstone Unit : Fiscal year 2004

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Rice Lake (including the Sandstone Unit) and Mille Lacs National Wildlife Refuges outlines Refuge accomplishments during the 2004...

  7. Rice Lake National Wildlife Refuge : Mille Lacs National Wildlife Refuge : Sandstone Unit : Fiscal year 2003

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Rice Lake (including the Sandstone Unit) and Mille Lacs National Wildlife Refuges outlines Refuge accomplishments during the 2003...

  8. SOURCE ASSESSMENT: CRUSHED SANDSTONE, QUARTZ, AND QUARTZITE, STATE-OF-THE-ART

    Science.gov (United States)

    This report describes a study of atmospheric emissions from the crushed sandstone, quartz, and quartzite industry. Particulates are emitted from drilling, blasting, loading and unloading trucks, transport on unpaved roads, washing, crushing, screening, conveying, and stockpiling....

  9. Low Shock Pressure Recovery Experiments with Dry Sandstone Samples Within the MEMIN Research Program

    Science.gov (United States)

    Schmitt, R. T.; Reimold, W. U.; Hornemann, U.

    2011-03-01

    Within the MEMIN program shock recovery experiments with Seeberger sandstone were carried out in the pressure range of 5 to 12.5 GPa to investigate shock effects in quartz and the influence of porosity on progressive shock metamorphism.

  10. Numerical Modeling of Porosity Alteration at the Sub-Surface of Impacts in Sandstone

    Science.gov (United States)

    Güldemeister, N.; Wünnemann, K.; Buhl, E.; Kenkmann, T.; Durr, N.; Hiermaier, S.

    2012-03-01

    In the framework of the MEMIN project the effects of hypervelocity impact shock compression and release in sandstone are investigated. The increase of porosity as a result of the rarefaction wave has been modeled and quantified in impact experiments.

  11. Impacts into Sandstone: Crater Morphology, Crater Scaling and the Effects of Porosity

    Science.gov (United States)

    Poelchau, M. H.; Dufresne, A.; Kenkmann, T.

    2011-03-01

    Crater morphology results from impact cratering experiments in sandstone within the MEMIN program are presented and compared to other brittle materials. The effects of porosity on crater shape, volume and cratering efficiency are analyzed.

  12. Heavy mineral sorting in downwards injected Palaeocene sandstone, Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Svendsen, Johan Byskov;

    2011-01-01

    Post-depositional remobilization and injection of sand are often seen in deep-water clastic systems and has been recently recognised as a significant modifier of deep-water sandstone geometry. Large-scale injectite complexes have been interpreted from borehole data in the Palaeocene Siri Canyon...... of depositional structures in deep-water sandstones, the distinction between "in situ" and injected or remobilised sandstones is often ambiguous. Large scale heavy mineral sorting (in 10 m thick units) is observed in several reservoir units in the Siri Canyon and has been interpreted to represent the depositional...... sorting. In this study we describe an example of effective shear-zone sorting of heavy minerals in a thin downward injected sandstone dyke which was encountered in one of the cores in the Cecilie Field, Siri Canyon. Differences in sorting pattern of heavy minerals are suggested as a tool for petrographic...

  13. Desalination of salt damaged Obernkirchen sandstone by an applied DC field

    DEFF Research Database (Denmark)

    Matyščák, Ondřej; Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge

    2014-01-01

    Soluble salts are considered as one of the most common causes for decay of building materials. In the present work, an electrokinetic method for desalination of sandstones from a historic warehouse was tested. The sandstones claddings were removed from the warehouse during a renovation action...... in the stones, i.e. the present investigation faces more challenges relevant to a real desalination action. Experiments were conducted with two Obernkirchen sandstones from the same warehouse, but with different levels of salt concentrations and porosity. The investigation includes removal of the most common...... salts: chlorides, nitrates, sulphates. In the experimental setup the electrodes were placed in a clay poultice: a mixture of kaolinite, calcite and distilled water. An electric direct current (DC) field was applied to the sandstone.By applying 2mA for 5–11days it was possible to reduce the chloride...

  14. Diagenetic facies controls on pore structure and rock electrical parameters in tight gas sandstone

    Science.gov (United States)

    Liu, Hongping; Zhao, Yanchao; Luo, Yang; Chen, Zhaoyou; He, Sheng

    2015-08-01

    Rock electrical parameters of tight gas sandstone show large variations in the T2 member in Dingbei Block, Ordos Basin, China. Applying the same rock electrical parameters in water saturation calculations would lead to large errors. Based on casting thin sections, x-ray diffraction, scanning electron microscopy (SEM), cathode luminescence, porosity and permeability, image analysis, and high-pressure mercury intrusion/withdrawal method, identification of the diagenetic facies are first conducted, and then their pore structure and their relationship with rock electrical parameters are investigated. Five diagenetic facies (A-E), which are identified based mainly on pore types and authigenic minerals, have different pore structure and rock electrical parameters. Conceptual models that incorporate the rock properties of each diagenetic facies have been built, before applying the electrical efficiency theory to explain the values of cementation exponent (m) and saturation exponent (n). A conventional network model, a shunt pore model, a netted pore model, and a dotted line model are utilized to mimic the intergranular pores, authigenic kaolinite intercrystal pores, carbonate-cement dissolution pores, and clay-matrix intercrystal pores, respectively. A decrease of the contents of large pores increases electrical efficiency and therefore reduces m. The saturation exponent, which depends on the distribution of water and gas, can be better understood by applying the different pore models. In the shunt and netted pore models, gas displacement starts from the larger pores and smaller pores provide alternative conduction pathways, hence sustaining electrical efficiency and decreasing n. Clay-matrix intercrystal pores are mainly micropores, since the brine in the rocks are isolated after gas displacement, reducing overall electrical efficiency and dramatically increasing the value of n in the diagenetic facies, which is dominated by clay-matrix intercrystal pores.

  15. Prediction of Diagenetic Facies using Well Logs: Evidences from Upper Triassic Yanchang Formation Chang 8 Sandstones in Jiyuan Region, Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Lai Jin

    2016-05-01

    Full Text Available The eighth member of Upper Triassic Yanchang Formation (Chang 8 is the major oil reservoir unit in Jiyuan oil field, though with the high potential for oil exploration. The Chang 8 sandstones are characterized with low porosity, low permeability and strong microscopic heterogeneities due to the complex deep-burial diagenetic history. Detailed petrological studies by thin section, X-ray diffraction, scanning electron microscopy, core analysis have been used to investigate the lithogology characteristics, diagenesis, diagenetic minerals and their coupling impacts on reservoir property. The results show that Chang 8 sandstones comprise fine to mediumgrained subarkoses, feldspathic litharenites. The pore systems are dominated by remaining primary intergranular pores, secondary dissolution porosity and micropores. Then, five diagenetic facies were divided in Chang 8 sandstones based on the type and degree of diagenesis, diagenetic minerals assemblages and their coupling effects on the reservoir quality. They consist of grain-coating chlorite weak dissolution facies, unstable component dissolution facies, tight compaction facies, clay minerals filling facies and carbonate cementation facies. The well logging response characteristics of various diagenetic facies are summarized on Gamma Ray (GR, Density Logging (DEN, Acoustic (AC, Compensated Neutron Logging (CNL, and True Formation Resistivity (RT by translating diagenetic facies to well log responses, the diagenetic facies were defined by a set of log responses, and porosity, permeability ranges for each diagenetic facies were determined from core analyses. Well log data of Luo 13 and Chi 212 are processed to evaluate the accuracy of the predictive model. The diagenetic facies are predicted on the vertical profile based on the generated model. Predicted distribution of diagenetic facies precisely coincide with the microscopic observations, and diagenetic facies in Chang 8 sandstones are generally

  16. Rock-Arch Instability Characteristics of the Sandstone Plate under Different Loading Conditions

    OpenAIRE

    Shuren Wang; Paul Hagan; Baowen Hu; Kanchana Gamage; Cheng Yan; Dianfu Xu

    2014-01-01

    Under the concentrated loading and the uniform loading, the tests on the brittle fracture and the hinged arching until the rock-arch instability of the sandstone plate were conducted using self-developed loading device, and the sensitivity of influent factors on the rock-arch failure was analyzed by numerical test based on the particle flow code (PFC). The results showed that sandstone plate instability presented four phases: small deformation elastic stage, brittle fracture arching stage, ...

  17. Research and development of GIS evaluation system for sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    GIS evaluation system for sandstone-type uranium deposits is based on uranium geology, it consists of data management, analysis, visualization etc. This paper introduces the study and development of GIS evaluation system for sandstone-type uranium deposits, and describes the main functions of the system, such as data management, bore hole data analysis, spatial data analysis, metallogenic prognosis, information extraction and so on. (authors)

  18. Investigated Miscible CO2 Flooding for Enhancing Oil Recovery in Wettability Altered Chalk and Sandstone Rocks

    OpenAIRE

    Tabrizy, Vahid Alipour

    2012-01-01

    The thesis addresses oil recovery by miscible CO2 flooding from modified sandstone and chalk rocks. Calcite mineral surface is modified with stearic acid (SA) and asphaltene, and the silicate mineral surfaces are modified with N,N-dimethyldodecylamine (NN-DMDA) and asphaltene. The stability of adsorbed polar components in presence of SO4 2- and Mg2 + ions is also investigated. Recovery from sandstone cores is consistently lower than that from chalk cores saturated with...

  19. Origin of brackish groundwater in a sandstone aquifer on Bornholm, Denmark

    DEFF Research Database (Denmark)

    Jørgensen, Niels Oluf; Heinemeier, Jan

    2008-01-01

    A multi-isotope approach in combination with hydrochemical data and borehole logging is applied to identify the source of brackish groundwater in a borehole in the well field of Neksø Municipal Waterworks in Bornholm, Denmark. The aquifer lithology consists of fractured Lower Cambrian sandstones...... reflecting long water-rock interaction and suggest a contribution of palaeowater from the fractured crystalline basement which has intruded into the Lower Cambrian sandstone aquifer....

  20. Geochemical characterization of Cretaceous sand-stones from the Southern Benue Trough, Nigeria

    Institute of Scientific and Technical Information of China (English)

    Odigi M.I.; Amajor L.C.

    2009-01-01

    Geochemical studies of sandstones from the three lithostratigraphic successions in the southern Benue Trough of Nigeria were undertaken for a geochemical characterization of the sandstones, and to assess their strati-graphic and source evolution.Major and trace elements data were obtained from outcrop sandstone samples. The SIO2/Al2O2, Fe2O3/K2O ra-tios and CaO contents have been used to characterize the Cretaceous sandstones into Al-rich and high and low Fe2O3/K2O ratio sandstones. Results indicate that there are geochemical features that display stratigraphic trends across the succession from the Asu River Group, Eze-Aku Group to the proto-Niger Delta succession which may imply a discontinuous evolution from different source terrains of Precambrian and Mesozoic ages that supplied the sediments. The Asu River Group sandstones have lower SiO2, Al2O3, Fe2O3 and higher MgO; the Eze-Aku sand-stones have higher TiO2, CaO, alkalis and lower MgO while the proto-Niger Delta sandstones have higher SiO2, Al2O3, Fe2O3 and lower alkalis and CaO. These discontinuities signify the influence of tectonic impulses that af-fected the southern Benue Trough during the Cretaceous time. Changes in ratios of TiO2/Al2O3, Fe2O3, Cr and Zr suggest an increasingly mafic contribution to the depositional basin with time. The chemical index of alteration in-creases with time, possibly suggesting that a more intense weathering regime in the hinterland developed with time.

  1. Geochemical and Mineralogical Composition of Bima Sandstone Deposit, Yola Area, NE Nigeria

    Directory of Open Access Journals (Sweden)

    D.M. Orazulike

    2011-03-01

    Full Text Available The aim of this study is to determine the geochemical and mineralogical composition of Bima Sandstone deposite of northeastern Nigeria. A total number of sixteen (16 sandstone samples were collected in Yola area inorder to classify the deposit of the Bima Sandstone exposed in this area on the basis of its chemical and mineralogical make-up. All the samples were selected randomly and subjected to both geochemical and petrographic studies. Relative concentration of the major oxide groups such as silica and alumina alkali oxides, iron oxide and magnesia has been used to classify the deposit. The results of the log of ratio of the m ajor oxide groups indicate that Bima Sandstone of the study area can be classified as greywackes, arkoses and lithic arenites including sub-greywackes and protoquartzites. The abundant alkali values as shown by the relatively high log K2O/Na2O ratio in most of the samples indicated immature sandstones whereas low alkali values in sam ples F, H and M revealed mature sandstones. The enrichment of silica (quartz over Al2O3 (log SiO2/Al2O3<1.5 indicate that Bima Sandstone has undergone long period of transportation and have been subjected to intense weathering resulting in the destruction of other minerals especially plagioclase and potassium feldspars during transportation. Microscopic examination of about sixteen slides (16 of Bima Sandstone under both plane and cross polars revealed the following average mineralogical composition: quartz (65% feldspars (14%, mica (9%, iron oxide (5%, calcite (3% further confirms quartz/lithic arenites and greywackes as some of the predominant sedimentary rocks in the study area.

  2. Comparative Study of Structure Using Composite Members And Conventional Members

    Directory of Open Access Journals (Sweden)

    Charuhas K. Karalkar

    2015-05-01

    Full Text Available There are different methods of construction for building structure. The most popular conventional structures used are reinforced cement concrete structures, pure steel structures and Timber Structures. In the modern age the rapid growth in population and continuous influx of people from rural to metros; buildings are constructed on a large scale and with great Architectural requirement. In this paper a new type of structure is introduced which involves use of composite members. To reduce the construction time, material quantity and cost the composite members are used. The composite members here mean use of steel sections as structural steel along with timber. Here by using composite members for miscellaneous Architectural building, lot of saving has been done in material, construction time and cost. It saves approximately 20-25% cost of structure if conventional type is used. Composite members used are Structural steel and solid timber compare to conventional steel or RCC members.

  3. Effects of Thermal Treatment on the Dynamic Mechanical Properties of Coal Measures Sandstone

    Science.gov (United States)

    Li, Ming; Mao, Xianbiao; Cao, Lili; Pu, Hai; Mao, Rongrong; Lu, Aihong

    2016-09-01

    Many projects such as the underground gasification of coal seams and coal-bed methane mining (exploitation) widely involve the dynamic problems of coal measures sandstone achieved via thermal treatment. This study examines the dynamic mechanical properties of coal measures sandstone after thermal treatment by means of an MTS653 high-temperature furnace and Split Hopkinson pressure bar test system. Experimental results indicate that 500 °C is a transition point for the dynamic mechanical parameters of coal measures sandstone. The dynamic elastic modulus and peak strength increase linearly from 25 to 500 °C while the dynamic peak strain decreases linearly over the same temperature range. The dynamic elastic modulus and peak strength drop quickly from 500 to 800 °C, with a significant increase in the dynamic peak strain over the same temperature range. The rock mechanics are closely linked to material composition and mesoscopic structure. Analysis by X-ray diffraction and scanning electron microscopy indicate that the molecules inside the sandstone increase in density due to the thermal expansion of the material particles, which effectively improves the deformation resistance and carrying capacity of the sandstone and reduces the likelihood of axial deformation. With heat treatment that exceeds 500 °C, the dynamic mechanical properties rapidly weaken due to the decomposition of kaolinite; additionally, hot cracking of the mineral particles within the materials arises from coal sandstone internal porosity, and other defects gradually appear.

  4. Brittleness index and seismic rock physics model for anisotropic tight-oil sandstone reservoirs

    Institute of Scientific and Technical Information of China (English)

    Huang Xin-Rui; Huang Jian-Ping; Li Zhen-Chun; Yang Qin-Yong; Sun Qi-Xing; Cui Wei

    2015-01-01

    Brittleness analysis becomes important when looking for sweet spots in tight-oil sandstone reservoirs. Hence, appropriate indices are required as accurate brittleness evaluation criteria. We construct a seismic rock physics model for tight-oil sandstone reservoirs with vertical fractures. Because of the complexities in lithology and pore structure and the anisotropic characteristics of tight-oil sandstone reservoirs, the proposed model is based on the solid components, pore connectivity, pore type, and fractures to better describe the sandstone reservoir microstructure. Using the model, we analyze the brittleness sensitivity of the elastic parameters in an anisotropic medium and establish a new brittleness index. We show the applicability of the proposed brittleness index for tight-oil sandstone reservoirs by considering the brittleness sensitivity, the rock physics response characteristics, and cross-plots. Compared with conventional brittleness indexes, the new brittleness index has high brittleness sensitivity and it is the highest in oil-bearing brittle zones with relatively high porosity. The results also suggest that the new brittleness index is much more sensitive to elastic properties variations, and thus can presumably better predict the brittleness characteristics of sweet spots in tight-oil sandstone reservoirs.

  5. Macro/Microtesting and Damage and Degradation of Sandstones under Dry-Wet Cycles

    Directory of Open Access Journals (Sweden)

    Xinrong Liu

    2016-01-01

    Full Text Available In terms of the degradation of mechanical parameters of rock mass in the hydrofluctuation belt of a reservoir bank slope arising from rainfall and the reservoir level fluctuation, the moderately weathered sandstone in a side slope of the Three Gorges Reservoir Region is selected as a research object to carry out “drying-saturation-drying” tests for disks with two thicknesses (h=25 mm, h=50 mm in different cycles; a spiral CT machine, an ultrasonic velocity meter, and a light Schmidt hammer are utilzed to conduct nondestructive testing on dry-wet cycles; through the Brazilian splitting test, the uniaxial tensile strength of “dry” and “saturated” sandstones under different dry-wet cycles is obtained. The research shows that, with the increase of the dry-wet circles (n, the longitudinal wave velocity and the rebound strength of sandstones are linearly decreased with n; the uniaxial tensile strength of sandstones and the mean CT number of cross sections are logarithmically decreased with n; the fitting equation of macro/micromechanical parameters and dry-wet cycles (n of sandstones is raised, which is provided as a reference basis for the weathering process of sandstones under dry-wet cycles.

  6. Regional paleotopographic trends and production, Muddy Sandstone (Lower Cretaceous), central and northern Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Dolson, J. (Amoco Production Co., Denver, CO (United States)); Muller, D.; Stein, J.A. (Amoco Production Co., Houston, TX (United States)); Evetts, M.J. (Amoco Production Co., Tulsa, OK (United States))

    1991-03-01

    The Muddy Sandstone and equivalent strata have produced more than 1.5 billion bbl of oil-equivalent hydrocarbons. Production is controlled principally by unconformities formed during a relative sea level low-stand. Reservoirs are found in paleohills of older marine sandstones, younger valley fills and associated alluvial plain channel sandstones, and transgressive marine deposits. At least ten paleodrainage basins existed at maximum lowstand. A regional drainage divide formed in southern Wyoming and separated southeast-flowing from north-west-flowing alluvial systems. Local tributaries stripped drainage divides of fine-grained detritus derived from the underlying Skull Creek Shale and older marine sandstones. In contrast, trunk streams carried medium- and coarse grained-sands eroded from eastern, southern, and western provenances of Paleozoic and Mesozoic strata. The best fluvial reservoirs are developed within these coarser grained trunk systems. Reservoir data display little or no correlation between depth and porosity due to secondary dissolution porosity developed at all depths. Valley fill and channel reservoirs have produced at least 359 MMBOE, onlap cycles another 315+ MMBOE, and older marine buried-hill reservoirs more than 268 MMBOE. The best per-field reserves are from marine sandstones. Regional production patterns reflect proximity to mature Skull Creek and Mowry shale source beds and favorable trapping conditions within individual paleodrainages. Future hydrocarbon exploration successes will require drilling to the Muddy Sandstone in deeper basin settings and a better understanding of the role of unconformities and diagenesis in controlling hydrocarbon accumulations.

  7. Adsorption difference of Pb2+ and Zn2+ in sandstone and breccia

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The adsorption difference of Pb2+ and Zn2+ in sandstone and breccia of Pb-Zn Mine of Yunnan Prov ince was studied by using modem instrument analysis method and fractal geometry theory. The results show that the adsorption capacity (Q) of Pb2+ in this two rocks is bigger than that of Zn2+, and Q in various initial concentration solutions obey s Freundlich experiential formula. The value of 1/n on the adsorption Pb2 and Zn2+ in sandstone hardly has any difference.but the value ofk differs observably. The adsorption process ofZn2+ or Pb2+ in sandstone or breccia from solution is fraetal-like. The kinetic equation of adsorption is lgp = k alg t or Q = abt( 1 + bt) -1 and the values oflg k. a. and D of breecia are bigger than those of sandstone at 30 and 50 ℃. These parameters decrease basically with the increase of tempernture.The adsorption capacity of Pb2+ is almost equal in sandstone and breccia, but the adsorption ability of Zn2+ in breeciais stronger than that in sandstone.

  8. Improvement of attenuation functions of a clayey sandstone for landfill leachate containment by bentonite addition.

    Science.gov (United States)

    Ruiz, Ana I; Fernández, Raúl; Sánchez Jiménez, Nicanor; Rodríguez Rastrero, Manuel; Regadío, Mercedes; de Soto, Isabel S; Cuevas, Jaime

    2012-03-01

    Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have been evaluated for consideration as landfill liners. A lab-scale test was carried out under controlled conditions with different amended natural sandstones whereby leachate was passed through the compacted mixtures. The compacted samples consisted of siliceous sand (quartz-feldspar sand separated from the arkose sandstone) and clay (purified clay from arkose sandstone and two commercial bentonites) materials that were mixed in different proportions. The separation of mineral materials from a common and abundant natural source, for soil protection purposes, is proposed as an economic and environmentally efficient practice. The liner qualities were compared for their mineralogical, physicochemical and major ions transport and adsorption properties. Although all samples fulfilled hydraulic conductivity requirements, the addition of bentonite to arkose sandstone was determined to be an effective strategy to decrease the permeability of the soil and to improve the pollutants retention. The clay materials from arkose sandstone also contributed to pollutant retention by a significant improvement of the cation exchange capacity of the bulk material. However, the mixtures prepared with clay materials from the arkose, exhibited a slight increase of hydraulic conductivity. This effect has to be further evaluated.

  9. Reservoir characterization of the Mt. Simon Sandstone, Illinois Basin, USA

    Science.gov (United States)

    Frailey, S.M.; Damico, J.; Leetaru, H.E.

    2011-01-01

    The integration of open hole well log analyses, core analyses and pressure transient analyses was used for reservoir characterization of the Mt. Simon sandstone. Characterization of the injection interval provides the basis for a geologic model to support the baseline MVA model, specify pressure design requirements of surface equipment, develop completion strategies, estimate injection rates, and project the CO2 plume distribution.The Cambrian-age Mt. Simon Sandstone overlies the Precambrian granite basement of the Illinois Basin. The Mt. Simon is relatively thick formation exceeding 800 meters in some areas of the Illinois Basin. In the deeper part of the basin where sequestration is likely to occur at depths exceeding 1000 m, horizontal core permeability ranges from less than 1 ?? 10-12 cm 2 to greater than 1 ?? 10-8 cm2. Well log and core porosity can be up to 30% in the basal Mt. Simon reservoir. For modeling purposes, reservoir characterization includes absolute horizontal and vertical permeability, effective porosity, net and gross thickness, and depth. For horizontal permeability, log porosity was correlated with core. The core porosity-permeability correlation was improved by using grain size as an indication of pore throat size. After numerous attempts to identify an appropriate log signature, the calculated cementation exponent from Archie's porosity and resistivity relationships was used to identify which porosity-permeability correlation to apply and a permeability log was made. Due to the relatively large thickness of the Mt. Simon, vertical permeability is an important attribute to understand the distribution of CO2 when the injection interval is in the lower part of the unit. Only core analyses and specifically designed pressure transient tests can yield vertical permeability. Many reservoir flow models show that 500-800 m from the injection well most of the CO2 migrates upward depending on the magnitude of the vertical permeability and CO2 injection

  10. The influence of clay minerals on acoustic properties of sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Olav

    1997-12-31

    This thesis aims to provide better understanding of the relationship between the acoustic properties and the petrophysical/mineralogical properties in sand-prone rock. It emphasizes the influence of clay minerals. The author develops a method to deposit clay minerals/mineral aggregates in pore space of a rigid rock framework. Kaolinite aggregates were flushed into porous permeable Bentheimer sandstone to evaluate the effect of pore filling minerals on porosity, permeability and acoustic properties. The compressional velocity was hardly affected by the clay content and it was found that the effect of minor quantities of pore filling minerals may be acoustically modelled as an ideal suspension, where the pore fluid bulk modulus is modified by the bulk modulus of the clay minerals. The influence of clays on acoustic velocities in petroleum reservoir rocks was investigated through ultrasonic measurements of compressional- and shear-waves on core material from reservoir and non-reservoir units on the Norwegian Continental Shelf. The measured velocities decrease as the porosity increases, but are not strongly dependent on the clay content. The measured velocities are less dependent on the petrophysical and lithological properties than indicated by previous authors and published mathematical models, and stiffness reduction factors are introduced in two of the models to better match the data. Velocities are estimated along the wellbores based on non-sonic well logs and reflect well the actual sonic log well measurements. In some wells the compressional velocity cannot be modelled correctly by the models suggested. Very high compressional wave anisotropy was measured in the dry samples at atmospheric conditions. As the samples were saturated, the anisotropy was reduced to a maximum of about 30% and decreases further upon pressurization. Reservoir rocks retrieved from 2500 m are more stress dependent than those retrieved from less than 200 m depth. 168 refs., 117 figs., 24

  11. The Members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 128 Member States of the Agency as of 18 September 1998. The new Member since the last issue of the list (INFCIRC/2/50) is Burkina Faso. In an attachment the dates on which the present 128 states became Members, and the state (Benin) whose application for membership of the Agency has been recommended by the Board of Governors to be considered at the 42nd session of the General Conference are given

  12. The members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 127 Member States of the Agency as of 1 January 1998. The new Members since the last issue of of the list (INFCIRC/2/49) are Malta and the Republic of Moldova. In an attachment are given the dates on which the present 127 states become Members, the state (Burkina Faso) whose application for membership of the Agency has been approved by the General Conference but which has not deposited an instrument of acceptance of the Statute

  13. The members of the Agency

    International Nuclear Information System (INIS)

    The new members since the last list of Member States of the Agency was issued (INFCIRC/2/Rev.42) are: Armenia, Coratia, the Czech Republic, Lithuania, the Marshall Islands, the Slovak Republic and Uzbekistan. The Attachment to the circular shows the dates on which the 120 States became members of the Agency, as well as those States whose application for membership of the Agency was approved by the General Conference, but who have not yet deposited an instrument of acceptance of the Statute

  14. GREYBULL SANDSTONE PETROLEUM POTENTIAL ON THE CROW INDIAN RESERVATION, SOUTH-CENTRAL MONTANA

    Energy Technology Data Exchange (ETDEWEB)

    David A. Lopez

    2000-12-14

    Evaluation of the Lower Cretaceous Greybull Sandstone on the Crow Indian Reservation for potential stratigraphic traps in the valley-fill sandstone was the focus of this project. The Crow Reservation area, located in south-central Montana, is part of the Rocky Mountain Foreland structural province, which is characterized by Laramide uplifts and intervening structural basins. The Pryor and Bighorn mountains, like other foreland uplifts, are characterized by asymmetrical folds associated with basement-involved reverse faults. The reservation area east of the mountains is on the northwestern flank of the Powder River Basin. Therefore, regional dips are eastward and southeastward; however, several prominent structural features interrupt these regional dips. The nearly 4,000 mi{sup 2} reservation is under explored but has strong potential for increased oil and gas development. Oil and gas production is well established in the Powder River Basin of Wyoming to the south as well as in the areas north and west of the reservation. However, only limited petroleum production has been established within the reservation. Geologic relations and trends indicate strong potential for oil and gas accumulations, but drilling has been insufficient for their discovery. The Greybull Sandstone, which is part of the transgressive systems tract that includes the overlying Fall River Sandstone, was deposited on a major regional unconformity. The erosional surface at the base of the Greybull Sandstone is the +100 Ma, late Aptian-Early Albian regional unconformity of Weimer (1984). This lowstand erosional surface was controlled by a basin-wide drop in sea level. In areas where incised Greybull channels are absent, the lowstand erosional unconformity is at the base of the Fall River Sandstone and equivalent formations. During the pre-Greybull lowstand, sediment bypassed this region. In the subsequent marine transgression, streams began to aggrade and deposit sand of the lower Greybull Sandstone

  15. Predicting cement distribution in geothermal sandstone reservoirs based on estimates of precipitation temperatures

    Science.gov (United States)

    Olivarius, Mette; Weibel, Rikke; Whitehouse, Martin; Kristensen, Lars; Hjuler, Morten L.; Mathiesen, Anders; Boyce, Adrian J.; Nielsen, Lars H.

    2016-04-01

    Exploitation of geothermal sandstone reservoirs is challenged by pore-cementing minerals since they reduce the fluid flow through the sandstones. Geothermal exploration aims at finding sandstone bodies located at depths that are adequate for sufficiently warm water to be extracted, but without being too cemented for warm water production. The amount of cement is highly variable in the Danish geothermal reservoirs which mainly comprise the Bunter Sandstone, Skagerrak and Gassum formations. The present study involves bulk and in situ stable isotope analyses of calcite, dolomite, ankerite, siderite and quartz in order to estimate at what depth they were formed and enable prediction of where they can be found. The δ18O values measured in the carbonate minerals and quartz overgrowths are related to depth since they are a result of the temperatures of the pore fluid. Thus the values indicate the precipitation temperatures and they fit the relative diagenetic timing identified by petrographical observations. The sandstones deposited during arid climatic conditions contain calcite and dolomite cement that formed during early diagenesis. These carbonate minerals precipitated as a response to different processes, and precipitation of macro-quartz took over at deeper burial. Siderite was the first carbonate mineral that formed in the sandstones that were deposited in a humid climate. Calcite began precipitating at increased burial depth and ankerite formed during deep burial and replaced some of the other phases. Ankerite and quartz formed in the same temperature interval so constrains on the isotopic composition of the pore fluid can be achieved. Differences in δ13C values exist between the sandstones that were deposited in arid versus humid environments, which suggest that different kinds of processes were active. The estimated precipitation temperatures of the different cement types are used to predict which of them are present in geothermal sandstone reservoirs in

  16. ANALYSIS OF OIL-BEARING CRETACEOUS SANDSTONE HYDROCARBON RESERVOIRS, EXCLUSIVE OF THE DAKOTA SANDSTONE, ON THE JICARILLA APACHE INDIAN RESERVATION, NEW MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    Jennie Ridgley

    2000-01-21

    An additional 450 wells were added to the structural database; there are now 2550 wells in the database with corrected tops on the Juana Lopez, base of the Bridge Creek Limestone, and datum. This completes the structural data base compilation. Fifteen oil and five gas fields from the Mancos-ElVado interval were evaluated with respect to the newly defined sequence stratigraphic model for this interval. The five gas fields are located away from the structural margins of the deep part of the San Juan Basin. All the fields have characteristics of basin-centered gas and can be considered as continuous gas accumulations as recently defined by the U.S. Geological Survey. Oil production occurs in thinly interbedded sandstone and shale or in discrete sandstone bodies. Production is both from transgressive and regressive strata as redefined in this study. Oil production is both stratigraphically and structurally controlled with production occurring along the Chaco slope or in steeply west-dipping rocks along the east margin of the basin. The ElVado Sandstone of subsurface usage is redefined to encompass a narrower interval; it appears to be more time correlative with the Dalton Sandstone. Thus, it was deposited as part of a regressive sequence, in contrast to the underlying rock units which were deposited during transgression.

  17. The Members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 136 Member States of the Agency as of 6 May 2003. The new Members since the last issue of the list (INFCIRC/2/57) are Eritrea and the Republic of Seychelles. Cambodia withdrew from the Agency with effect from 26 March 2003. The dates on which the present 136 Member States became Members are given in an Attachment. It also shows the States whose application for membership of the Agency has been approved by the General Conference but which has not yet deposited an instrument of acceptance of the Statute

  18. The Members of the Agency

    International Nuclear Information System (INIS)

    No new Member has joined the Agency since the last list of Member States was issued (INFCIRC/2/Rev.45). The Attachment hereto shows the dates on which the present 122 Member States became Members. It also shows the State whose application for membership of the Agency has been approved by the General Conference but which has not yet deposited an instrument of acceptance of the Statute and the States whose applications for membership have been recommended by the Board of Governors for approval by the General Conference

  19. Petrophysical and petrographic evaluation of Sidri Member of Belayim Formation, Badri field, Gulf of Suez, Egypt

    Science.gov (United States)

    Abudeif, A. M.; Attia, M. M.; Radwan, A. E.

    2016-03-01

    Presence of sandstone streaks in Sidri Member within Belayim Formation that lies between two productive zones; Kareem Formation and Hammam Faraun Member, was the main reason to perform this study. It may represent a good hydrocarbon reservoir and will be added to the Egyptian oil production in some wells of Badri field. This Member has high resistivity signature on Electric-logs responses which attracted the attention to investigate its occurrence in the field, to delineate its distribution all-over the area, to evaluate the petrographic and petrophysical characteristics and to evaluate its productivity. Petrographic and petrophysical analyses of these sand zones were undertaken using thin section samples. The electric logs and subsurface geologic data was used to evaluate the main reservoir characteristics of the Sidri sandstone such as lithology, cementation, shale volume, porosity (Φ), effective porosity (Φ eff), estimated permeability (K), fluid saturation, fluid type and Net pay thickness. This study revealed that, Sidri sandstone facies was classified into two mainly sandy facies; blocky sandy facies which located at the northern part of the field and streaky sandy facies at the southern area of the field. These two facies are separated by shaley facies. Some wells were studied to represent the two sandy facies in Sidri Member and these sand intervals have not been tested yet. These sands consist of quartz grains with grey and pink feldspars as accessory minerals, with siliceous and calcareous cementation, with good porosity. Petrophysical evaluation of this sand unit indicated that it is hydrocarbon bearing formation in three wells and water bearing one in other wells. Electrical logs analysis (Resistivity, Density-Neutron, Sonic and Gamma-Ray) revealed that The volume of shale in this sandstone, the effective porosity, the water saturation, the estimated permeability, the hydrocarbon saturation, and the net-pay thickness are varying from 9 to 13%, 19

  20. Salamanca sandstone: a good GHSR not suitable for all construction purposes.

    Science.gov (United States)

    Pereira, Dolores; Blanco, Jose Antonio; Nespereira, Jose

    2016-04-01

    Salamanca sandstone, which in fact is an opal-cemented formation of sandstones and conglomerates, was used in the construction of many historical buildings of Salamanca old city, as well as other places nearby. Salamanca is recognized as World Heritage site since 1988, precisely because the homogeneous architecture and the use of local natural resources, as the Salamanca sandstone, the Villamayor sandstone and some local granites. The reason for using the sedimentary stone was the easy access of the resource, as the city is built on top of the Salamanca sandstone Formation, a late Cretaceous-early Palaeocene deposit. This formation consists of siliciclastic successions that were deposited in braided fluvial systems. These materials are derived from a deeply weathered Variscan basement showing ferruginous alteration that adds an aesthetic value to the global view of the natural stone. However, after several centuries, the stone has started to show serious problems due to water absorption, mainly in those places where it was used as basement of the buildings. Restoration of historical buildings should consider the use of the same original material when replacement is requested. But when this original material has been demonstrated to be not appropriate for long-term constructions, a matching and preferable natural stone should be used for replacement. There is such possibility in Salamanca and this has not have to mean the disregard of the Salamanca sandstone for other uses. The natural stone has been used for interior use and for sculpture with quality results. We present the Salamanca sandstone as a possible candidate to be taken into account as GHSR, supported by complete characterization and use recommendation.

  1. Mechanistic study of wettability alteration of oil-wet sandstone surface using different surfactants

    International Nuclear Information System (INIS)

    Graphical abstract: Zeta potential of oil-wet quartz powder treated with different surfactants at different concentrations. - Highlights: • Mechanisms of wettability alteration during surfactant flooding were studied. • Different analytical instruments were used to study sandstone wettability alteration. • Surfactants’ structure plays a great role in wettability alteration of solid surface. • CTAB irreversibly desorbs carboxylic acid from solid surface by ionic interaction. • Cationic surfactant is more effective in wettability alteration of sandstone surface. - Abstract: Different analytical methods including Fourier transform infrared (FTIR), atomic force microscopy (AFM), zeta potential measurements, contact angle measurements and spontaneous imbibition tests were utilized to make clear the mechanism for wettability alteration of oil-wet sandstone surface using different surfactants. Results show that among three types of surfactants including cationic surfactants, anionic surfactants and nonionic surfactants, the cationic surfactant CTAB demonstrates the best effect on the wettability alteration of oil-wet sandstone surface. The positively charged head groups of CTAB molecules and carboxylic acid groups from crude oil could interact to form ion pairs, which could be desorbed from the solid surface and solubilized into the micelle formed by CTAB. Thus, the water-wetness of the solid surface is improved. Nonionic surfactant TX-100 could be adsorbed on oil-wet sandstone surface through hydrogen bonds and hydrophobic interaction to alter the wettability of oil-wet solid surface. The wettability alteration of oil-wet sandstone surface using the anionic surfactant POE(1) is caused by hydrophobic interaction. Due to the electrostatic repulsion between the anionic surfactant and the negatively charged surface, POE(1) shows less effect on the wettability alteration of oil-wet sandstone surface

  2. Mechanistic study of wettability alteration of oil-wet sandstone surface using different surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Bao-feng, E-mail: hbf370283@163.com; Wang, Ye-fei; Huang, Yong

    2015-03-01

    Graphical abstract: Zeta potential of oil-wet quartz powder treated with different surfactants at different concentrations. - Highlights: • Mechanisms of wettability alteration during surfactant flooding were studied. • Different analytical instruments were used to study sandstone wettability alteration. • Surfactants’ structure plays a great role in wettability alteration of solid surface. • CTAB irreversibly desorbs carboxylic acid from solid surface by ionic interaction. • Cationic surfactant is more effective in wettability alteration of sandstone surface. - Abstract: Different analytical methods including Fourier transform infrared (FTIR), atomic force microscopy (AFM), zeta potential measurements, contact angle measurements and spontaneous imbibition tests were utilized to make clear the mechanism for wettability alteration of oil-wet sandstone surface using different surfactants. Results show that among three types of surfactants including cationic surfactants, anionic surfactants and nonionic surfactants, the cationic surfactant CTAB demonstrates the best effect on the wettability alteration of oil-wet sandstone surface. The positively charged head groups of CTAB molecules and carboxylic acid groups from crude oil could interact to form ion pairs, which could be desorbed from the solid surface and solubilized into the micelle formed by CTAB. Thus, the water-wetness of the solid surface is improved. Nonionic surfactant TX-100 could be adsorbed on oil-wet sandstone surface through hydrogen bonds and hydrophobic interaction to alter the wettability of oil-wet solid surface. The wettability alteration of oil-wet sandstone surface using the anionic surfactant POE(1) is caused by hydrophobic interaction. Due to the electrostatic repulsion between the anionic surfactant and the negatively charged surface, POE(1) shows less effect on the wettability alteration of oil-wet sandstone surface.

  3. Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

    DEFF Research Database (Denmark)

    Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius;

    2008-01-01

    Currently, the question of whether or not the presence of oil in sandstone inhibits quartz cementation and preserves porosity is still debated. Data from a number of Cambrian sandstone oil fields and dry fields have been studied to determine the effects of oil emplacement on quartz cementation...... cementation is derived from internal sources. Rather, in spite of large variation in porosity and quartz cement content, a regular pattern of porosity decrease is related to increasing temperature or depth. The observed heterogeneity is due to local factors that influence the precipitation of quartz cement......, including sandstone architecture, i.e., distribution of shales within the sandstone bodies, and sandstone thickness. Heterogeneity is inherent to sandstone architecture and to the fact that silica for quartz cementation is derived from heterogeneously distributed local pressure solution. Models predicting...

  4. Mapping porosity anomalies in deep Jurassic sandstones - an example from the Svane-1A area, Danish Central Graben

    Energy Technology Data Exchange (ETDEWEB)

    Abramovitz, T.

    2011-07-01

    Hydrocarbon-bearing Upper Jurassic sandstone reservoirs at depths of more than 5000 m may form a future exploration target in the Danish Central Graben. The Upper Jurassic sandstone play in the Danish sector has historically been less successful than in the neighbouring Norwegian and British sectors of the North Sea. This is mainly due to poor reservoir quality of the sandstones. However, the discovery in 2001 of an oil accumulation at a depth of more than 5000 m in the Svane-1 well has triggered renewed interest in the Upper Jurassic High Temperature - High Pressure (HTHP) sandstone play in Danish waters. The Jurassic plays comprise sandstone reservoirs deposited in a variety of environments, ranging from fluvial to deep marine. This paper presents a study of a minor area around the Svane-1A well in the Tail End Graben. The objective was to map acoustic impedance variations and hence to identify porosity anomalies associated with Jurassic sandstone units. (LN)

  5. Evidence of Multi-Stage Hydrocarbon Charging and Biodegradation of the Silurian Asphaltic Sandstones in the Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    刘洛夫

    2002-01-01

    Asphalts distributed widely in the Silurian sandstones of the Tarim Basin include dry asphalt, soft asphalt and heavy oil. These asphaltic sandstones underwent multi-episodic sedimentary and tectonic events, and their occurrence is diverse and complex, being mixed with normal oil usually. So far, very little work has been done on the asphaltic sandstone origin and hydrocarbon charging ages. After detailed study on the Silurian sandstones, the following highlights were obtained from the analytical results: distribution of the mixed asphalt, heavy oil and normal oil in the Silurian sandstones is the result of multi-stage hydrocarbon charging from the Lower Paleozoic marine source rocks; the characters of asphalts formed from oils of different charging ages are of difference; the most important process constraining.the asphaltic sandstone origin is thought to be biodegradation.

  6. Profile Report: ASHA Member Survey.

    Science.gov (United States)

    Weinberg, Armin D.; And Others

    1981-01-01

    The American School Health Association (ASHA) surveyed its members who were nurses to identify their needs for improved member programs and services. Recommendations include that the needs of both school-based nurses and those with administrative roles be considered independently for annual meeting programs. (JN)

  7. Estimation of uranium migration parameters in sandstone aquifers.

    Science.gov (United States)

    Malov, A I

    2016-03-01

    The chemical composition and isotopes of carbon and uranium were investigated in groundwater samples that were collected from 16 wells and 2 sources in the Northern Dvina Basin, Northwest Russia. Across the dataset, the temperatures in the groundwater ranged from 3.6 to 6.9 °C, the pH ranged from 7.6 to 9.0, the Eh ranged from -137 to +128 mV, the total dissolved solids (TDS) ranged from 209 to 22,000 mg L(-1), and the dissolved oxygen (DO) ranged from 0 to 9.9 ppm. The (14)C activity ranged from 0 to 69.96 ± 0.69 percent modern carbon (pmC). The uranium content in the groundwater ranged from 0.006 to 16 ppb, and the (234)U:(238)U activity ratio ranged from 1.35 ± 0.21 to 8.61 ± 1.35. The uranium concentration and (234)U:(238)U activity ratio increased from the recharge area to the redox barrier; behind the barrier, the uranium content is minimal. The results were systematized by creating a conceptual model of the Northern Dvina Basin's hydrogeological system. The use of uranium isotope dating in conjunction with radiocarbon dating allowed the determination of important water-rock interaction parameters, such as the dissolution rate:recoil loss factor ratio Rd:p (a(-1)) and the uranium retardation factor:recoil loss factor ratio R:p in the aquifer. The (14)C age of the water was estimated to be between modern and >35,000 years. The (234)U-(238)U age of the water was estimated to be between 260 and 582,000 years. The Rd:p ratio decreases with increasing groundwater residence time in the aquifer from n × 10(-5) to n × 10(-7) a(-1). This finding is observed because the TDS increases in that direction from 0.2 to 9 g L(-1), and accordingly, the mineral saturation indices increase. Relatively high values of R:p (200-1000) characterize aquifers in sandy-clayey sediments from the Late Pleistocene and the deepest parts of the Vendian strata. In samples from the sandstones of the upper part of the Vendian strata, the R:p value is ∼ 24, i.e., sorption processes are

  8. Interaction of oil components and clay minerals in reservoir sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Changchun Pan; Linping Yu; Guoying Sheng; Jiamo Fu [Chinese Academy of Sciences, State Key Lab. of Organic Geochemistry, Wushan, Guangzhou (China); Jianhui Feng; Yuming Tian [Chinese Academy of Sciences, State Key Lab. of Organic Geochemistry, Wushan, Guangzhou (China); Zhongyuan Oil Field Co., Puyang, Henan (China); Xiaoping Luo [Zhongyuan Oil Field Co., Puyang, Henan (China)

    2005-04-15

    The free oil (first Soxhlet extract) and adsorbed oil (Soxhlet extract after the removal of minerals) obtained from the clay minerals in the <2 {mu}m size fraction as separated from eight hydrocarbon reservoir sandstone samples, and oil inclusions obtained from the grains of seven of these eight samples were studied via GC, GC-MS and elemental analyses. The free oil is dominated by saturated hydrocarbons (61.4-87.5%) with a low content of resins and asphaltenes (6.0-22.0% in total) while the adsorbed oil is dominated by resins and asphaltenes (84.8-98.5% in total) with a low content of saturated hydrocarbons (0.6-9.5%). The inclusion oil is similar to the adsorbed oil in gross composition, but contains relatively more saturated hydrocarbons (16.87-31.88%) and less resins and asphaltenes (62.30-78.01% in total) as compared to the latter. Although the amounts of both free and adsorbed oils per gram of clay minerals varies substantially, the residual organic carbon content in the clay minerals of the eight samples, after the free oil extraction, is in a narrow range between 0.537% and 1.614%. From the decrease of the percentage of the extractable to the total of this residual organic matter of the clay minerals with burial depth it can be inferred that polymerization of the adsorbed polar components occurs with the increase of the reservoir temperature. The terpane and sterane compositions indicate that the oil adsorbed onto the clay surfaces appears to be more representative of the initial oil charging the reservoir than do the oil inclusions. This phenomenon could possibly demonstrate that the first oil charge preferentially interacts with the clay minerals occurring in the pores and as coatings around the grains. Although the variation of biomarker parameters between the free and adsorbed oils could be ascribed to the compositional changes of oil charges during the filling process and/or the differential maturation behaviors of these two types of oils after oil

  9. Sedimentary and petrofacies analyses of the Amasiri Sandstone, southern Benue Trough, Nigeria: Implications for depositional environment and tectonic provenance

    Science.gov (United States)

    Okoro, A. U.; Igwe, E. O.; Nwajide, C. S.

    2016-11-01

    This study was undertaken to determine the depositional environment, provenance and tectonic setting for the Turonian Amasiri Sandstone, southern Benue Trough, Nigeria, using lithofacies analysis and re-appraisal of petrography of the sandstones. Local stratigraphy and field relationships show a thick succession of shales alternating with elongate/parallel sandstone ridges extending eastwards from Akpoha to Amasiri through Itigidi and Ugep to Apiapum areas. Lithofacies analysis reveals 9 lithofacies suggestive of storm (mass flow) and tidal shelf processes. These include dark grey to black laminated shale/silty mudstones, bioturbated mudstones, coquinoid limestones, very fine-grained bioturbated sandstones with shell hash/debris in places and limestone rip-up clasts, massive and chaotic sandy conglomerate with rip - up clasts, fine to medium-grained, parallel laminated sandstone, hummocky cross-stratified, massive, medium to coarse-grained sandstones, medium to very coarse-grained, planar cross-bedded sandstone, with clay-draped foresets and Ophiomorpha burrows, and coarse-grained trough cross-bedded sandstone. Petrofacies analysis identifies the sandstones as feldspathic and arkosic arenites. Ternary plot of framework mineralogy indicates derivation from an uplifted continental block related to the nearby Oban Massif and Cameroon Basement Complex.

  10. Mechanistic study of wettability alteration of oil-wet sandstone surface using different surfactants

    Science.gov (United States)

    Hou, Bao-feng; Wang, Ye-fei; Huang, Yong

    2015-03-01

    Different analytical methods including Fourier transform infrared (FTIR), atomic force microscopy (AFM), zeta potential measurements, contact angle measurements and spontaneous imbibition tests were utilized to make clear the mechanism for wettability alteration of oil-wet sandstone surface using different surfactants. Results show that among three types of surfactants including cationic surfactants, anionic surfactants and nonionic surfactants, the cationic surfactant CTAB demonstrates the best effect on the wettability alteration of oil-wet sandstone surface. The positively charged head groups of CTAB molecules and carboxylic acid groups from crude oil could interact to form ion pairs, which could be desorbed from the solid surface and solubilized into the micelle formed by CTAB. Thus, the water-wetness of the solid surface is improved. Nonionic surfactant TX-100 could be adsorbed on oil-wet sandstone surface through hydrogen bonds and hydrophobic interaction to alter the wettability of oil-wet solid surface. The wettability alteration of oil-wet sandstone surface using the anionic surfactant POE(1) is caused by hydrophobic interaction. Due to the electrostatic repulsion between the anionic surfactant and the negatively charged surface, POE(1) shows less effect on the wettability alteration of oil-wet sandstone surface.

  11. Heavy mineral sorting in downwards injected Palaeocene sandstone, Siri Canyon, Danish North Sea

    Science.gov (United States)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Svendsen, Johan Byskov; Weibel, Rikke

    2011-05-01

    Post-depositional remobilization and injection of sand are often seen in deep-water clastic systems and have been recently recognised as a significant modifier of deep-water sandstone geometry. Large scale injectite complexes have been interpreted from borehole data in the Palaeocene Siri Canyon near the Danish Central Graben of the North Sea hydrocarbon province. The emplacement of large scale injectite complexes has been commonly attributed to seismic activity and consequent sand liquefaction. However, due to very small differences in textural and compositional properties, and the lack of depositional structures in deep-water sandstones, the distinction between "in situ" and injected or remobilized sandstones is often ambiguous. Large scale heavy mineral sorting (in 10 m thick units) is observed in several reservoir units in the Siri Canyon and has been interpreted to represent the depositional sorting. In this study we describe an example of effective shear-zone sorting of heavy minerals in a thin downwards injected sandstone dyke which was encountered in one of the cores in the Cecilie Field, Siri Canyon. Differences in sorting pattern of heavy minerals are suggested as a tool for petrographic/geochemical distinction between "in situ" sandstones and their related injectites, especially where primary sedimentary structures are removed by fluidization or minor remobilization.

  12. Stratigraphy and petroleum potential of Trout Creek and Twentymile sandstones (Upper Cretaceous), Sand Wash Basin, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Siepman, B.R.

    1985-05-01

    The Trout Creek and Twentymile Sandstones (Mesaverde Group) in Moffat and Routt Counties, Colorado, are thick, upward-coarsening sequences that were deposited along the western margin of the Western Interior basin during Campanian time. These units trend northeast-southwest and undergo a facies change to coal-bearing strata on the northwest. Surface data collected along the southeastern rim of the Sand Wash basin were combined with well-log data from approximately 100 drill holes that have penetrated the Trout Creek or Twentymile in the subsurface. The sandstones exhibit distinctive vertical profiles with regard to grain size, sedimentary structures, and biogenic structures. A depositional model that incorporates the key elements of the modern Nile River (northeast Africa) and Nayarit (west-central Mexico) coastal systems is proposed for the Trout Creek and Twentymile sandstones and associated strata. The model depicts a wave-dominated deltaic, strand-plain, and barrier-island system. Depositional cycles are asymmetrical in cross section as they are largely progradational and lack significant transgressive deposits. Source rock-reservoir rock relationships are ideal as marine shales underlie, and coal-bearing strata overlie sheetlike reservoir sandstones. Humic coal, the dominant source of Mesaverde gas, generates major quantities of methane upon reaching thermal maturity. Existing Mesaverde gas fields are largely structural traps, but stratigraphic and combination traps may prove to be equally important. The sparsely drilled deeper part of the basin warrants testing as large, overpressured-gas accumulations in tight-sandstone reservoirs are likely to be found.

  13. Development of aeroradiometric and aeromagnetic information for the exploration of sandstone type uranium deposit

    International Nuclear Information System (INIS)

    Through the study of aeroradiometric and aeromagnetic characteristics of five known sandstone type uranium deposits in the southern margin of Yili basin, it is emphasized that anomalies of four parameters such as uranium wide channel in downward window (Udw), uranium narrow channel in upward window (Uu), uranium wide channel in upward window (Uuw) and uranium narrow channel in downward window (Ud) are direct indicators for sandstone type uranium deposit. According to the discussed correlation between aeroradiometric information, the author points out that aeroradiometric correlation analysis is not a suitable method for the prognosis of interlayer oxidation zone type uranium deposit, but the negative correlation areas of K and Th delineated by correlation analysis is the favorable occurrence location for paleochannel sandstone type uranium deposit. After extracting weak magnetic anomalies, it was put forward for the first time that covered oxidation zone can be delineated by the distribution range of weak magnetic anomalies. Aeroradiometric and aeromagnetic computer prognosis models were established for sandstone type uranium deposit. Metallogenetic prognosis was carried out in the whole Basin. With this model, 14 pieces of prospective areas were delineated, so as to further advance ground geophysical survey, and expand prospecting achievements in the Yili basin. In a word, aeroradiometric and aeromagnetic information still play an important role in prospecting in-situ leachable sandstone type uranium deposit. (authors)

  14. The Members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 125 Member States of the Agency as of 1 September 1997. The new Member since the last issue of the list (INFCIRC/2/Rev.48) is Latvia. In an Attachment are given the dates on which the present 125 States became Members, the State (Republic of Moldova) whose application for membership of the Agency has been approved by the General Conference but which has not yet deposited an instrument of acceptance of the Statute and the States (Malta and Burkina Faso) whose applications for membership have been recommended by the Board of Governors for approval by the General Conference

  15. Element mobility during diagenesis: sulphate cementation of Rotliegend sandstones, Southern North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Gluyas, J. [BP Venezuela, Caracas (Venezuela); Jolley, L.; Primmer, T. [BP Exploration, Aberdeen (United Kingdom)

    1998-11-01

    Several wells in the Amethyst gas field of the North Sea`s Southern Basin are poor producers and have been since they were drilled. The lack of gas flow from these wells is due to pervasive cementation of the Rotliegend sandstone reservoir by either anhydrite and/or barite. Both minerals precipitated late in the diagenetic history of the sandstones. Such cements form up to 20% of the total rock. Isotopic and geochemical evidence indicate that the source of the elements for these sulphate cements was outside the Rotliegend sandstone. The sulphur and oxygen isotope data for the anhydrite and barite are unlike those which could have precipitated in Lower Permian times from an evaporating marine basin. Both the timing and distribution of these cements is taken to indicate that faulting allowed, or indeed promoted, mixing of sulphate-rich and barium-rich formation waters derived from the Zechstein and Carboniferous, respectively. (author)

  16. Monitoring hydrate formation and dissociation in sandstone and bulk with magnetic resonance imaging.

    Science.gov (United States)

    Baldwin, B A; Moradi-Araghi, A; Stevens, J C

    2003-11-01

    Magnetic resonance imaging (MRI) has been shown to be a very effective tool for monitoring the formation and dissociation of hydrates because of the large intensity contrast between the images of the liquid components and the solid hydrate. Tetrahydrofuran/water hydrate was used because the two liquid components are miscible and form hydrate at ambient pressure. These properties made this feasibility study proceed much faster than using methane/water, which requires high pressure to form the hydrate. The formation and dissociation was monitored first in a THF/water-saturated Berea sandstone plug and second in the bulk. In both cases it appeared that nucleation was needed to begin the formation process, i.e., the presence of surfaces in the sandstone and shaking of the bulk solution. Dissociation appeared to be dominated by the rate of thermal energy transfer. The dissociation temperature of hydrate formed in the sandstone plug was not significantly different from the dissociation temperature in bulk.

  17. Concurrent nitrate and Fe(III) reduction during anaerobic biodegradation of phenols in a sandstone aquifer

    DEFF Research Database (Denmark)

    Broholm, Mette; Crouzet, C.; Arvin, Erik;

    2000-01-01

    The biodegradation of phenols (similar to 5, 60, 600 mg 1(-1)) under anaerobic conditions (nitrate enriched and unamended) was studied in laboratory microcosms with sandstone material and groundwater from within an anaerobic ammonium plume in an aquifer, The aqueous phase was sampled and analyzed...... for phenols and selected redox sensitive parameters on a regular basis. An experiment with sandstone material from specific depth intervals from a vertical profile across the ammonium plume was also conducted. The miniature microcosms used in this experiment were sacrificed for sampling for phenols...... and selected redox sensitive parameters at the end of the experiment. The sandstone material was characterized with respect to oxidation and reduction potential and Fe(II) and Fe(III) speciation prior to use for all microcosms and at the end of the experiments for selected microcosms. The redox conditions...

  18. 3D AVO Analysis for Identifying Thin Continental Sandstone Interbeds and Deep Volcanic Rocks

    Institute of Scientific and Technical Information of China (English)

    Fulei; WangJianmin; CuiFenglin; XuJianjun; ZhangXiangjun; KongXiangbo

    2005-01-01

    AVO characteristics were ambiguous in thin-layer interbed sandstones and mudstones of terrestrial facies of Daqing area. Described in this paper is the 3D AVO analysis and real examples in the Songzhan region in the north of the Songliao basin. The AVO responses of the Fuyu sandstone reservoir, obtained through special AVO processing and interpretation as well as the AVO forwardmod eling under the constraints of logging data, were evident in the Sheng-81 well. It was concluded that the Fuyu sandstone reservoir presented an AVO anomaly of “amplitudes increasing with offsets”.At the same time, the deep volcanic reservoirs were ascertained and the channels of volcanic eruption were delineated at the intersections of faults in Sanzhao area, through a 3D AVO analysis, which coincided with the theory of geodynamics and tectonophysics.

  19. ESEM-EDS investigation of the weathering of a heritage Sydney sandstone.

    Science.gov (United States)

    Ip, Kin Hong; Stuart, Barbara; Ray, Abhi; Thomas, Paul

    2011-04-01

    The degradation of Sydney sandstone used to build the heritage St Mary's Cathedral in Sydney, Australia, has been investigated using environmental scanning electron microscopy combined with energy dispersive X-ray spectroscopy. This technique provided the structural details of the cementing clay and an elemental characterization the sandstone. The observed differences in the elemental composition of the unweathered and weathered sandstones were associated with changes to the clay microstructure upon weathering. The results support the substitution theory that Fe3+ replaces Al3+ in the kaolinite clay component upon weathering. An examination of the impurities present prior to a nonstructural iron removal treatment revealed the presence of minerals that may provide a source of the elements responsible for the substitution process.

  20. [Application of near-infrared spectrum technology to research of weathering of red sandstone relics].

    Science.gov (United States)

    Jiang, Xiao-Dong; Cao, Jian-Jin; Li, Yi-An; Yin, Jin-Long; Ye, Jin-Long

    2011-08-01

    In the present paper, with near infrared spectroscopy technology, the weathering mechanism of red sandstone relics was studied. Six groups of red sandstone samples were analyzed using near infrared spectroscopy technology. The results show that the near-infrared spectroscopy technology can analyze the material composition of red sandstone before and after weathering, aiming to explore their components changed. So it is a quick and efficient means of research with characteristic of less measurement sample and speed and non-damage and being pollution-free compared with other research techniques. All the characteristic shows that it is also well for studying other stone cultural relics. Especially for those with sampling difficulty and treasure valuable, non-destruction of stone cultural relics is particularly important. So with time advancing, near infrared technology as a research means of stone relics, its meaning will be more prominent.

  1. The metallogenic condition analysis and prospecting direction of Chuanjing depression sandstone type uranium deposit

    International Nuclear Information System (INIS)

    Through the research on the metallogenic condition analysis of Chuanjing depression sandstone type uranium deposit come to a conclusion, that in terms of the Chuanjing depression, is qualified sandstone-type uranium deposits, but according to different districts. The basic conditions of uranium mineralization coupling is poorer, So, it is difficult to find large sandstone type uranium deposit in this area, at present, we have found some uranium mineralization and uranium abnormalities. But, it will be broken in the groundwater hydrodynamic conditions which are relatively good location, these area have good hydrogeology conditions, Channel sands are dominated by the ancient migration of underground water channel, with a complete and independent power system ground water for the migration of oxygenated water containing uranium to provide a good channel, but also for the enrichment of uranium to provide a better Space, lots more abundant in the reducing agent mineralization. future exploration of these sites is our main site. (author)

  2. New members of Datura family

    CERN Document Server

    Rosaev, Alexey

    2015-01-01

    The problem of origin and age of asteroid families is studied very intensively. Youngest families are most interesting due to possibility of the reconstruction collisional history. Here we report about three new members of Datura Family

  3. Microfractures in Quartz Grains as a Measurement of Maximum Effective Stress in Sandstone Reservoirs

    Science.gov (United States)

    Mehrkian, K.; Aubourg, C.; Girard, J. P.; Teinturier, S.; Hoareau, G.

    2015-12-01

    Effective stress, defined as the load transmitted from particle to particle in the solid framework of a rock, plays a significant role in controlling mechanical compaction and thus reservoir quality in sandstones. Mechanical compaction in sandstones takes place through rearrangement and ductile/ brittle deformation of framework grains during progressive burial. It is primarily dependent on the magnitude and evolution of effective stress during burial, and on the nature and textural properties of framework grains (mineralogy, grain size/shape, sorting…) and pore-filing solid cements when present. Here, we propose a method to directly evaluate maximum effective stress in sandstone reservoirs by quantifying the brittle deformation of quartz grains evidenced through the development of microfractures. Quartz microfracturing is documented and quantified by examining thin sections of core samples under SEM CL microscopy. Previous published experimental studies and observations made on natural samples indicate that quartz burial-induced microfracturing in sandstones is mainly affected by effective stress, but also reflects other factors such as grain size, sorting and proportion of ductile grains (clays, micas…). In order to investigate the quantitative impact of such factors altogether, we have conducted compaction experiments (>30 tests) on 10 types of sands at 25°C, under dry conditions and pressures up to 55 Mpa. The resulting compressed sands were studied by optical microscopy to quantify fractured quartz grains. Results were processed using R statistical computing language via a multi input model to define a simple equation that provides correction constants for each influencing factor. The resulting equation will then be used to calculate the maximum effective stress recorded by a sandstone reservoir during its burial history, based on the petrographic/mineralogical characteristics (thin section point-counting) and the fractured-grain ratio (obtained by SEM CL

  4. Detrital zircon geochronology of Siluro-Devonian sandstones, Rocky Mountains, northeastern British Columbia

    Energy Technology Data Exchange (ETDEWEB)

    Ross, G.M.; Geldsetzer, H.H.J. (Inst. of Sedimentary and Petroleum Geology, Calgary, AB (Canada)); McNicoll, V.J.; Parrish, R.R. (Geological Survey of Canada, Ottawa, ON (Canada)); Carr, S.D; Kinsman, A. (Carleton Univ., Ottawa, ON (Canada))

    1993-09-01

    Quartzose sandstones of latest Silurian to middle Devonian form the basal part of four unconformity-bounded, carbonate dominated shelf successions of the Alberta Basin in the Rocky Mountains of northeastern British Columbia; the Muncho-McConnell, Stone, Dunedin and Slave Point formations. The off-shelf equivalent to the Dunedin Formation is a massive channel deposit of quartzose sandstone that overlies basinal strata along a 30 km wide re-entrant in the northern part of the Ospika Embayment. Paleocurrent measurements from basal sandstones of the Dunedin Formation, including the channel deposit, contain a northeast-directed component over a large area and suggest possible sediment derivation from a western source area, perhaps reflecting uplift during the early phases of the Antler orogeny. To test this hypothesis, single detrital zircon grains were dated using the U-Pb technique, from sandstones of the shelf (Muncho-McConnell and Slave Point formations) and basinal settings (massive channel deposit) to examine their provenance. Twenty-nine single grain analyses from four different samples yielded a distinctive suite of U-Pb ages that are undistinguishable regardless of paleogeographic setting and closely match the ages of basement terranes that underlie the Peace River Arch in the autocthon to the east. These data support derivation of sediments of both basinal and shelf associations from the same source: the emergent Peace River Arch area to the east. Alternatively, to account for the northeasterly directed paleocurrents, Dunedin-equivalent quartzose sandstones of the basinal association could have been derived from the west and acquired their detrital zircon provenance signature by recycling pre-Devonian sandstones. 29 refs., 7 figs., 1 tab.

  5. CO2-Driven Convection Produced the Vertical Distribution of Sandstone Colors and Iron Concretions in Navajo Sandstone at Zion National Park, Utah (USA)

    Science.gov (United States)

    Kettler, R. M.; Loope, D. B.

    2011-12-01

    Along cliff faces exposed in Zion National Park (SW Utah), the porous and permeable Navajo Sandstone (Jurassic) is 700 m thick, and is capped by impermeable mudrocks and evaporites of the Carmel Formation. Previous workers have documented an areally extensive color pattern that is easily visible across much of southwestern and south-central Utah: the uppermost Navajo Sandstone is nearly white, the middle third of the formation is pink, and the lowermost fraction is reddish brown. To the northwest of the park, however, the formation is uniformly red (likely its primary color; G.B. Nielsen et al., 2009). Spheroidal concretions with dense, iron-oxide-cemented rinds and iron-poor cores are abundant in the pink and brown sandstones. Rhomb-shaped clots of iron oxide cement that are pseudomorphous after siderite are present in the cores of the largest concretions. The color variations are evidence that iron was transported from the upper portion of the Navajo SS to the lower portion. The pseudomorphs are evidence that the concretions are the oxidized remains of siderite-cemented precursors. The vertical iron transport and the precipitation of siderite require similar vertical transport of reducing, CO2-rich formation waters through the Navajo Sandstone. We argue that this circulation was driven in part by groundwater convection beneath a CO2 accumulation that was trapped below the Navajo-Carmel contact. This circulation caused aqueous iron and aqueous carbonate to be displaced downward and to accumulate (in the form of siderite) in the lower Navajo Sandstone. There are numerous CO2 reservoirs in the Colorado Plateau region; the gas was derived mainly from mantle sources. We hypothesize that, in the late Tertiary, the Carmel Formation capped a broad, structurally high accumulation of CO2 and CH4 in the Navajo Sandstone. The CH4 bleached the upper portion of the sandstone, releasing Fe2+ into the formation water. CO2 dissolved in the water, thereby increasing its density

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

    OpenAIRE

    Rossi Nieto, Carlos; Kälin, Otto; Arribas Mocoroa, José; Tortosa, A.

    2002-01-01

    The Triassic TAGI (Trias Argilo-Gréseux Inférieur) fluvial sandstones are the main oil reservoirs in the Berkine Basin, Algeria. Nonetheless, their provenance and diagenesis, and their impact on reservoir quality, are virtually unknown. Samples from the Ourhoud field, representing the Lower, Middle and Upper TAGI subunits, were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower TAGI sandstones have an average framework composition of Q98.3F0.6R1.1...

  7. The effects of impure CO2 on reservoir sandstones: results from mineralogical and geomechanical experiments

    Science.gov (United States)

    Marbler, H.; Erickson, K. P.; Schmidt, M.; Lempp, Ch.; Pöllmann, H.

    2012-04-01

    An experimental study of the behaviour of reservoir sandstones from deep saline aquifers during the injection and geological storage of CO2 with the inherent impurities SOX and NOX is part of the German national project COORAL*. Sample materials were taken from outcrops of possible reservoir formations of Rotliegend and Bunter Sandstones from the North German Basin. A combination of mineralogical alteration experiments and geomechanical tests was carried out on these rocks to study the potential effects of the impurities within the CO2 pore fluid. Altered rock samples after the treatment with CO2 + SOX/NOX in an autoclave system were loaded in a triaxial cell under in-situ pressure and temperature conditions in order to estimate the modifications of the geomechanical rock properties. Mineralogical alterations were observed within the sandstones after the exposure to impure supercritical (sc)CO2 and brine, mainly of the carbonatic, but also of the silicatic cements, as well as of single minerals. Besides the partial solution effects also secondary carbonate and minor silicate mineral precipitates were observed within the pore space of the treated sandstones. These alterations affect the grain structure of the reservoir rock. Results of geomechanical experiments with unaltered sandstones show that the rock strength is influenced by the degree of rock saturation before the experiment and the chemical composition of the pore fluid (scCO2 + SOX + NOX). After long-term autoclave treatment with impure scCO2, the sandstone samples exhibit modified strength parameters and elastic deformation behaviour as well as changes in porosity compared to untreated samples. Furthermore, the injected fluid volume into the pore space of sandstones from the same lithotype varies during triaxial loading depending on the chemistry of the pore fluid. CO2 with NOX and SOX bearing fluid fills a significantly larger proportion of the sandstone pore space than brine with pure scCO2. * The

  8. Reservoir quality of deeply buried sandstones – a study of burial diagenesis from the North Sea

    OpenAIRE

    2013-01-01

    List of papers and abstracts. Papers 1, 2, 3, 4 and 5 are removed from the thesis due to publisher restrictions. Paper 1: Maast, T. E., E. M. Jarsve, R. Flåt and J. Jahren, (submitted), The impact of quartz and illite cementation on deep reservoir quality in Upper Jurassic, syn-rift sandstones of the Central Graben, North Sea. Paper 2: Maast, T. E., J. Jahren, and K. Bjørlykke, 2011, Diagenetic controls on reservoir quality in Middle- to Upper Jurassic sandstones in the South Viking G...

  9. Quantifying the effect of squirt flow dispersion from compliant clay porosity in clay bearing sandstones

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2013-01-01

    Compliant porosity in the form of cracks is known to cause significant attenuation and velocity dispersion through pore pressure gradients and consequent relaxation, dubbed squirt flow. Squirt flow from cracks vanish at high confining stress due to crack closing. Studies on clay bearing sandstones......-squirt flow on the bulk modulus of a clay bearing sandstone. The predicted magnitude of the clay-squirt effect on the bulk modulus is compared with experimental data. The clay-squirt effect is found to possibly account for a significant portion of the deviances from Gassmann fluid substitution in claybearing...

  10. INFRARED THERMAL IMAGE STUDY ON THE FOREWARNING OF COAL AND SANDSTONE FAILURE UNDER LOAD

    Institute of Scientific and Technical Information of China (English)

    吴立新; 王金庄

    1997-01-01

    In the experimental study, AGE-782 thermal instrument was used to detect the infrared radiation variation of coal and sandstone (wave-length range 3.6~5.5 μm was used). It's discovered that coal and sandstone failure under load have three kinds of infrared thermal features as well as infrared forewarning messages. That are: (1) temperature rises gradually but drops before failure ; (2) temperature rises gradually but quickly rises before failure; (3) first rises,then drops and lower temperature emerges before failure. The further researches and the prospect of micro-wave remote sensing detection .on ground pressure is also discussed.

  11. Provenance of Permian Malužiná Formation sandstones (Hronicum, Western Carpathians: evidence from monazite geochronology

    Directory of Open Access Journals (Sweden)

    Vozárová Anna

    2014-10-01

    Full Text Available The Permian Malužiná Formation and the Pennsylvanian Nižná Boca Formation are Upper Paleozoic volcano- sedimentary complexes in the Hronicum nappe system. Sandstones, shales and conglomerates are the dominant lithological members of the Malužiná Formation sequence. Detrital monazites were analysed by electron microprobe, to obtain Th-U-Pb ages of the source areas. The majority of detrital monazites showed Devonian-Mississippian ages, ranging from 330 to 380 Ma with a weighted average of 351 ± 3.3 (2σ, that correspond well with the main phase of arcrelated magmatic activity in the Western Carpathians. Only a small portion of detrital monazites displayed Permian ages in the range of 250-280 Ma, with a significant maximum around 255 Ma. The weighted average corresponds to 255 ± 6.2 Ma. These monazites may have been partially derived from the synsedimentary acid volcanism that was situated on the margins of the original depositional basin. However, some of the Triassic ages (230-240 Ma, reflect, most likely, the genetic relationship with the overheating connected with Permian and subsequent Triassic extensional regime. Detrital monazite ages document the Variscan age of the source area and also reflect a gradual development of the Hronicum terrestrial rift, accompanied by the heterogeneous cooling of the lithosphere.

  12. Spatial Databases of Geological, Geophysical, and Mineral Resource Data Relevant to Sandstone-Hosted Copper Deposits in Central Kazakhstan

    Science.gov (United States)

    Syusyura, Boris; Box, Stephen E.; Wallis, John C.

    2010-01-01

    Central Kazakhstan is host to one of the world's giant sandstone-hosted copper deposits, the Dzhezkazgan deposit, and several similar, smaller deposits. The United Stated Geological Survey (USGS) is assessing the potential for other, undiscovered deposits of this type in the surrounding region of central Kazakhstan. As part of this effort, Syusyura compiled and partially translated an array of mostly unpublished geologic, geophysical, and mineral resource data for this region in digital format from the archives of the former Union of Soviet Socialists Republics (of which Kazakhstan was one of the member republics until its dissolution in 1991), as well as from later archives of the Republic of Kazakhstan or of the Kazakhstan consulting firm Mining Economic Consulting (MEC). These digital data are primarily map-based displays of information that were transmitted either in ESRI ArcGIS, georeferenced format, or non-georeferenced map image files. Box and Wallis reviewed all the data, translated Cyrillic text where necessary, inspected the maps for consistency, georeferenced the unprojected map images, and reorganized the data into the filename and folder structure of this publication.

  13. Depositional Environments of the Upper Permian Quartzose Sandstone (Shandong Province, North China):Insight from Trace Element Geochemistry

    Institute of Scientific and Technical Information of China (English)

    Dawei L; Zengxue Li; Jitao Chen; Ying Liu; Zengqi Zhang; Jipo Liang; Haiyan Liu

    2015-01-01

    The depositional environment of the Upper Permian quartzose sandstone (Kuishan sand-stone in Shihezi Formation of Upper Permian) in the North China epicontinental basin is controversial. In order to test the previous hypotheses, we analyzed sedimentological characteristics of the Kuishan sandstones in outcrops and boreholes, and carried out trace element geochemical analysis by electron probe microanalyzer. Three lithofacies were recognized, including normal-graded conglomerate (Cng), trough and planar cross-bedded coarse sandstone (CStpc), and planar cross-bedded medium sandstone (MSpc). Normal-graded conglomerate (Cng) formed in the meandering river or deltaic distributary channels. Trough and planar cross-bedded coarse sandstone (CStpc) formed in meandering river or distributary channels of near-source deltaic plain. Planar cross-bedded medium sandstone (MSpc) formed in the siliciclastic beach with high-to moderate-energy conditions. By the petrology and trace elements analysis, three relatively large-scale transgressions were revealed. Each transgression was re-flected by the lower content of Ba and ratios of Fe/Mn, and the high content of B and ratios of B/Ga. The ratios of Ni/Co of all samples are all lower than 2, suggesting oxygen-enriched shallower water en-vironment during deposition of the Kuishan sandstones.

  14. Microstructural analysis of quartz grains in Vasyugan suite sandstones of layer Ui1-21 in Kazanskoe deposit

    International Nuclear Information System (INIS)

    Microstructural analysis of quartz grains in sandstones revealed preferred directions which define and influence porosity and permeability anisotropy in oil and gas reservoirs In this research, we investigated the Upper Jurassic sandstone reservoir sediments from 14 wells in Kazanskoe field. The authors studied: the orientation of elongated quartz grains, and intergranular fracture within grains, as well as the pore space in oriented thin sections of sandstones. The analysis of elongated quartz grains in the bedding plane showed three main types of preferred directions in quartz grain orientation along different axes in sandstone reservoirs. Obtained results allow identifying a variability of facies and dynamic depositional environment for Upper Jurassic sandstone formation. Subsequently, these results can be used in field modeling, as well as pattern optimization of injection and production wells

  15. SUBSURFACE WELL-LOG CORRELATION OF ARSENIC-BEARING LITHOFACIES IN THE PERMIAN GARBER SANDSTONE AND WELLINGTON FORMATION, CENTRAL OKLAHOMA AQUIFER (COA), CLEVELAND COUNTY, OKLAHOMA

    Science.gov (United States)

    The fluvial Garber Sandstone and the underlying Wellington Formation are important sources of drinking water in central Oklahoma. These formations, which make up much of the COA, consist of amalgamated sandstones with some interbedded mudstones, siltstones, and local mudstone- a...

  16. Relative importance of cementation vs. compaction to porosity evolution in quartzose sandstone: Tensleep and Quadrant formations (Pennsylvanian), northern Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    James, W.C. (Ohio State Univ., Columbus (USA))

    1990-05-01

    Very fine- to fine-grained, very well-sorted quartzarenites in the Tensleep (average sandstone unit thickness is 4 m) and Quadrant (average unit thickness is 2 m) formations have average porosity values of 10 and 5%, respectively (range 0-23%, Tensleep; range 0-21%, Quadrant). Porosity evolution in sandstones was strongly influenced by proximity to contacts with interbedded carbonates and the timing of cement precipitation. Early anhydrite (A) and dolomite (D) cements are preferentially located near upper and lower contacts of sandstones. The average minus-cement porosity for these types of cemented zones is 37%. A later quartz (Q) cement is concentrated toward the middle of sandstone bodies, with average minus-cement porosity values near 30%. High porosity zones ({>=} 10%) are associated with D + A/D + A + Q ratios of {<=} 0.5 and preferentially developed in the middle 50% of individual sandstone units. Estimates of initial porosity and measurements of volumes associated with cements, intergranular pressure solution, and present porosity allow assessment of the relative contributions of cementation and compaction to pore space reduction. On average in Tensleep sandstone, about 74% (lower 25% of individual sandstones) and 77% (upper 25%) of porosity reduction was the result of cementation. However, in the middle 50% of sandstones, compaction (47%) was subequal in importance with cementation (53%) as the cause of pore space loss. In the Quadrant, porosity was primarily destroyed by cementation regardless of location within a sandstone body (75% lower, 78% middle, 82% upper). The difference in behavior of the middle of Quadrant vs. Tensleep sandstone bodies may be related to the absolute timing and abundance of quartz cementation.

  17. Sedimentological Characteristics and Geochemistry of Ajali Sandstone Exposed at Ofe-Jiji and Environs, Northern Anambra Basin, Nigeria

    Directory of Open Access Journals (Sweden)

    Y.B. Gideon

    2014-01-01

    Full Text Available Textural, mineralogical and structural studies as well as outcrop mapping of sandstone in Ofe-Jiji and environs were carried out in order to interpret depositional environment of Ajali sandstone exposed at Ofe-Jiji and environs of the northern Anambra Basin. The sandstone is false bedded, medium-coarse grained (average of 1.13 mm in diameter, poorly sorted and strongly coarsely skewed with an average skewness value of -0.72. Chemical analysis indicates that the sandstone exhibits average SiO2 contents ranging from 59.12 to 60.20% with an average value of 59.80% while alumina (Al2O3 content range between 2.51 and 2.75% with an average of 2.63%. The mineralogical composition shows on the average 56.98 quartz, 6.30 feldspar, 31.78% rock fragment and 4.93% matrix and cement. The major framework composition is Q56 F6 L36 which classifies the sandstone as lithic arenite. The sub angular texture and the geochemical assay of 22.74 ratios (SiO2/Al2O3 and 3.36 ratios (Na2O/K2O indicate low chemically stable minerals in the sandstone and depict mineralogical immaturity. Also, the average ZTR% index of 52.36% with Tourmaline as the least abundant of ultra-stable minerals indicates sub-mature to immature mineralogy of the sandstone. The sandstone may be described as Fe-Sandstone based on Herron Classification Scheme. The dominance of Fe2O3 (26.57% in the sandstone renders it ferruginous and reflects oxidizing environment. Ophiomorpha burrow in the upper unit of the beds strongly suggests fluvial origin.

  18. Seastacks buried beneath newly reported Lower Miocene sandstone, northern Santa Barbara County, California

    Energy Technology Data Exchange (ETDEWEB)

    Fritsche, A.E.; Hanna, F.M.

    1985-04-01

    Three large, isolated exposures of a light-gray, coarse-grained, thick-bedded sandstone unit occur in the northern San Rafael Mountains of Santa Barbara County, California. These rocks are moderately fossiliferous and contain Vertipecten bowersi, Amussiopecten vanvlecki, Aequipecten andersoni, Otrea howelli, shark teeth, whale bones, and regular echinoid spines. The fossils indicate that the sandstone unit, although previously reported as upper(.) Miocene, correlates best with the lower Miocene Vaqueros Formation. This unit was deposited in angular unconformity on a Cretaceous, greenish-gray turbidite sequence of interbedded sandstone and shale, and onlaps the unconformity erosion surface from west to east, the unit being thicker in the west and older at its base. The underlying Cretaceous sandstone beds are well indurated, and during the eastward transgression of the early Miocene sea, they resisted wave erosion and stood as seastacks offshore of the advancing coastline, thus creating a very irregular topographic surface upon which the Vaqueros Formation was deposited. Some seastacks were as much as 4 m tall, as indicated by inliers of Cretaceous rock surrounded by 4-m thick sections of the Vaqueros Formation.

  19. Prediction of calcite Cement Distribution in Shallow Marine Sandstone Reservoirs using Seismic Data

    Energy Technology Data Exchange (ETDEWEB)

    Bakke, N.E.

    1996-12-31

    This doctoral thesis investigates how calcite cemented layers can be detected by reflection seismic data and how seismic data combined with other methods can be used to predict lateral variation in calcite cementation in shallow marine sandstone reservoirs. Focus is on the geophysical aspects. Sequence stratigraphy and stochastic modelling aspects are only covered superficially. Possible sources of calcite in shallow marine sandstone are grouped into internal and external sources depending on their location relative to the presently cemented rock. Well data and seismic data from the Troll Field in the Norwegian North Sea have been analysed. Tuning amplitudes from stacks of thin calcite cemented layers are analysed. Tuning effects are constructive or destructive interference of pulses resulting from two or more closely spaced reflectors. The zero-offset tuning amplitude is shown to depend on calcite content in the stack and vertical stack size. The relationship is found by regression analysis based on extensive seismic modelling. The results are used to predict calcite distribution in a synthetic and a real data example. It is found that describing calcite cemented beds in shallow marine sandstone reservoirs is not a deterministic problem. Hence seismic inversion and sequence stratigraphy interpretation of well data have been combined in a probabilistic approach to produce models of calcite cemented barriers constrained by a maximum amount of information. It is concluded that seismic data can provide valuable information on distribution of calcite cemented beds in reservoirs where the background sandstones are relatively homogeneous. 63 refs., 78 figs., 10 tabs.

  20. Fluid Flow History in Lower Triassic Bulgo Sandstone, Central Sydney Basin, Australia

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The fluid flow history during diagenesis of the Lower Triassic Bulgo sandstone has been investigated through integrated analyses of petrography, stable isotope and fluid inclusion. Combined application of these techniques was intended to constrain the temperature, timing, chemistry and source of pore fluids during diagenetic cementation events in the Lower Triassic Bulgo sandstone. The dlagenesis proceeded in two different flow regimes: early dynamic fluid flow regime and late slow static fluid flow regime. The former was characterized by a slight increase of δ(18O) of pore waters form estimated -15 × 10-3 to -14 × 10-3 with the temperature increasing from ~ 10 ℃ to ~ 75 ℃. During early diagenesis, early clays and pore filling carbonates precipitated from the pore waters. The late slow flow/static fluid regime was characterized by a rapid 18O-enrichment process. δ(18O) of pore waters increased from -14× 10-3 to -5× 10-3 with the temperature increasing from 75 ℃ to 110 ℃. During the late diagenesis, kaolin (generation Ⅲ ), quartz and illite crystallized. Oil migrated to the sandstones of the Bulgo sandstone during quartz cementation.

  1. Provenance of Gebel El-Zeit sandstones, gulf of Suez, Egypt

    Science.gov (United States)

    Abdel-Wahab, Antar A.

    1992-01-01

    The Paleozoic elastic succession at Gebel Zeit chiefly consists of fine- to medium-grained quartz arenite, locally containing well-rounded quartz pebbles. The marine Araba Formation (Early Cambrian) was deposited during transgression over a Precambrian granite. The overlying Naqus Formation (Late Cambrian) is fluvial, except for the uppermost few meters. Paleocurrent data for the Araba and Naqus formations indicate derivation from the north-northeast and south-southwest respectively. Quartz typology, other morphologic features of quartz, and mineral inclusions in quartz, as well as the study of heavy minerals were used to determine the provenance of the sandstones. Quartz typology successfully identified a granitic source for the Araba Formation. A combination of parameters indicates that the Naqus Formation was derived chiefly from a metamorphic terrain. Two ratios, polycrystalline/monocrystalline quartz and undulose/non-undulose quartz, successfully distinguish sandstones of the Araba Formation from those of the Naqus Formation. These values are 0.14 and 0.25 for Araba sandstones and 0.26 and 0.46 for Naqus sandstones, respectively. These differences either reflect different source rocks, or have resulted from selective abrasion loss of polycrystalline quartz in the rigorous surf zone during the marine transgression that deposited the Araba Formation.

  2. SHORT COMMUNICATION: Sparsely encrusted hardground in the Darriwilian calcareous sandstone of Cape Pakri, NW Estonia (Baltica

    Directory of Open Access Journals (Sweden)

    Olev Vinn

    2015-08-01

    Full Text Available The occurrence of echinoderm and ptilodictyid bryozoan holdfasts on the surface of Darriwilian calcareous sandstone in northwestern Estonia indicates that it was lithified before encrustation. Pelmatozoans outnumber the bryozoans and cover a larger area of the hardground although both are very sparse. The hardground is very sparsely encrusted (0.37% of the total area studied and lacks signs of bioerosion.

  3. Diversity and complexity of the Araracuara sandstone flora and vegetation in the Colombian Amazon

    NARCIS (Netherlands)

    A.M. Cleef; M.V. Arbelaez Velasquez

    2005-01-01

    Insular open vegetation of the western Guayana Shield in Colombia (c.150-1000 m) surrounded by NW Amazon rain forest (over 3000 mm annual precipitation) has been botanically unexplored until the early 1990¿s. During recent botanical exploration of the sandstone plateaus of the Araracuara region a to

  4. Diagenesis and Its Effect on Reservoir Quality of Silurian Sandstones, Tabei Area, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    Zhang Jinliang; Jia Ying; Du Guilin

    2007-01-01

    The diagenetic processes of the Tabei sandstones in the Tarim Basin include compaction, cementation (quartz overgrowths, calcite, clay minerals and a minor amount of pyrite), and dissolution of the feldspar and calcite cement.Porosity was reduced by compaction from an assumed original 40% to about 22.1%. Cementation reduced porosity to 26.6%. The Tabei sandstones lost a little more porosity by compaction than by cementation. Quartz cementation,especially syntaxial quartz overgrowth, is a major cause of porosity-loss in many reservoirs in moderately to deeply buried sandstone. Calcite cementation played a key role in the porosity evolution of sandstones. At the early stage of burial, the early calcite cement occupied most of the pore spaces resulting in significant porosity. On the other hand, some primary porosity has been preserved due to incomplete filling or the presence of scattered patches of calcite cement. In addition to calcite, several clay minerals, including illite and chlorite occurred as pore-filling and pore-lining cements.The pore-lining chlorite may have helped in retaining the porosity by preventing the precipitation of syntaxial quartz overgrowths. Illite, which largely occurred as hair-like rims around the grains and bridges on the pore throats, caused a substantial deterioration of penetrability of the reservoir. Calcite cement dissolution was extensive and contributed significantly to the development of secondary porosity.

  5. Palaeoclimatic trends deduced from the hydrochemistry of a Triassic sandstone aquifer, U.K

    International Nuclear Information System (INIS)

    A detailed geochemical study (elemental, isotopic and dissolved inert gases) of unconfined and confined sections of the Triassic non-marine sandstone aquifer in Eastern England has been undertaken. Aspects of the recharge history of this aquifer over the past 40 000 years are revealed by examination of the data. (orig./HK)

  6. Combined rock-physical modelling and seismic inversion techniques for characterisation of stacked sandstone reservoir

    NARCIS (Netherlands)

    Justiniano, A.; Jaya, Y.; Diephuis, G.; Veenhof, R.; Pringle, T.

    2015-01-01

    The objective of the study is to characterise the Triassic massive stacked sandstone deposits of the Main Buntsandstein Subgroup at Block Q16 located in the West Netherlands Basin. The characterisation was carried out through combining rock-physics modelling and seismic inversion techniques. The app

  7. Assessment of undiscovered sandstone-hosted uranium resources in the Texas Coastal Plain, 2015

    Science.gov (United States)

    Mihalasky, Mark J.; Hall, Susan M.; Hammarstrom, Jane M.; Tureck, Kathleen R.; Hannon, Mark T.; Breit, George N.; Zielinski, Robert A.; Elliott, Brent

    2015-12-02

    The U.S. Geological Survey estimated a mean of 220 million pounds of recoverable uranium oxide (U3O8 ) remaining as potential undiscovered resources in southern Texas. This estimate used a geology-based assessment method for Tertiary sandstone-hosted uranium deposits in the Texas Coastal Plain sedimentary strata (fig.1).

  8. Assessment of tight-gas resources in Canyon sandstones of the Val Verde Basin, Texas, 2016

    Science.gov (United States)

    Schenk, Christopher J.; Tennyson, Marilyn E.; Klett, Timothy R.; Mercier, Tracey J.; Brownfield, Michael E.; Gaswirth, Stephanie B.; Hawkins, Sarah J.; Leathers-Miller, Heidi M.; Marra, Kristen R.; Finn, Thomas M.; Pitman, Janet K.

    2016-07-08

    Using a geology-based assessment methodology, the U.S. Geological Survey assessed mean resources of 5 trillion cubic feet of gas and 187 million barrels of natural gas liquids in tight-gas assessment units in the Canyon sandstones of the Val Verde Basin, Texas.

  9. Determining Upper Bounds for the Clay-squirt Effect in Clay Bearing Sandstone

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    Sonic measurements of saturated bulk moduli of clay bearing sandstones show larger values than expected by Gassmann modelling from dry rock properties. This causes difficulties in extrapolation of laboratory data to different saturants or frequencies. Squirt flow from the clay phase of the rock...

  10. Aeromagnetic gradient survey and elementary application in sandstone type uranium deposits prospecting

    International Nuclear Information System (INIS)

    The principle,advantage and data processing of aeromagnetic gradient survey approach is introduced in this paper, and used to identify the shallow surface faults, uranium ore-forming environment and depth of magnetic body for the prospecting of sandstone type uranium deposits. (authors)

  11. Borehole Breakouts Induced in Arkosic Sandstones and a Discrete Element Analysis

    Science.gov (United States)

    Lee, H.; Moon, T.; Haimson, B. C.

    2016-04-01

    A series of laboratory drilling experiments were conducted on two arkosic sandstones (Tenino and Tablerock) under polyaxial far-field stress conditions (σ h ≠ σ H ≠ σ v ). V-shaped breakouts, aligned with the σ h direction and revealing stress-dependent dimensions (width and length), were observed in the sandstones. The microscale damage pattern leading to the breakouts, however, is different between the two, which is attributed to the difference in their cementation. The dominant micromechanism in Tenino sandstone is intergranular microcracking occurring in clay minerals filling the spaces between clastic grains. On the other hand, intra- and transgranular microcracking taking place in the grain itself prevails in Tablerock sandstone. To capture the grain-scale damage and reproduce the failure localization observed around the borehole in the laboratory, we used a discrete element (DE) model in which a grain breakage algorithm was implemented. The microparameters needed in the numerical model were calibrated by running material tests and comparing the macroscopic responses of the model to the ones measured in the laboratory. It is shown that DE modeling is capable of simulating the microscale damage of the rock and replicating the localized damage zone observed in the laboratory. In addition, the numerically induced breakout width is determined at a very early stage of the damage localization and is not altered for the rest of the failure process.

  12. Reservoir heterogeneity in Carter Sandstone, North Blowhorn Creek oil unit and vicinity, Black Warrior Basin, Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, R.L.; Pashin, J.C.

    1992-05-01

    This report presents accomplishments made in completing Task 3 of this project which involves development of criteria for recognizing reservoir heterogeneity in the Black Warrior basin. The report focuses on characterization of the Upper Mississippian Carter sandstone reservoir in North Blowhorn Creek and adjacent oil units in Lamar County, Alabama. This oil unit has produced more than 60 percent of total oil extracted from the Black Warrior basin of Alabama. The Carter sandstone in North Blowhorn Creek oil unit is typical of the most productive Carter oil reservoirs in the Black Warrior basin of Alabama. The first part of the report synthesizes data derived from geophysical well logs and cores from North Blowhorn Creek oil unit to develop a depositional model for the Carter sandstone reservoir. The second part of the report describes the detrital and diagenetic character of Carter sandstone utilizing data from petrographic and scanning electron microscopes and the electron microprobe. The third part synthesizes porosity and pore-throat-size-distribution data determined by high-pressure mercury porosimetry and commercial core analyses with results of the sedimentologic and petrographic studies. The final section of the report discusses reservoir heterogeneity within the context of the five-fold classification of Moore and Kugler (1990).

  13. Interaction of Pseudomonas putida ATCC 12633 and Bacteriophage gh-1 in Berea Sandstone Rock.

    Science.gov (United States)

    Chang, P L; Yen, T F

    1985-12-01

    Measurements of the passage of Pseudomonas putida ATCC 12633 and a phage-resistant mutant through Berea sandstone rock were made. When bacteriophage gh-1 was adsorbed within the rock matrix, a reduction in the passage of the susceptible but not the resistant cells through the rock was observed.

  14. Thermal-mechanical coupled effect on fracture mechanism and plastic characteristics of sandstone

    Institute of Scientific and Technical Information of China (English)

    ZUO; JianPing; XIE; HePing; ZHOU; HongWei; PENG; SuPing

    2007-01-01

    Scanning electronic microscopy (SEM) was employed to investigate fractographs of sandstone in mine roof strata under thermal-mechanical coupled effect. Based on the evolution of sandstone surface morphology in the failure process and fractography, the fracture mechanism was studied and classified under meso and micro scales, respectively. The differences between fractographs under different temperatures were examined in detail. Under high temperature, fatigue fracture and plastic deformation occurred in the fracture surface. Therefore, the temperature was manifested by these phenomena to influence strongly on micro failure mechanism of sandstone. In addition, the failure mechanism would transit from brittle failure mechanism at low temperature to coupled brittle-ductile failure mechanism at high temperature. The variation of sandstone strength under different temperature can be attributed to the occurrence of plastic deformation, fatigue fracture, and microcracking. The fatigue striations in the fracture surfaces under high temperature may be interpreted as micro fold. And the coupled effect of temperature and tensile stress may be another formation mechanism of micro fold in geology.

  15. Salt precipitation due to supercritical gas injection: I. Capillary-driven flow in unimodal sandstone

    NARCIS (Netherlands)

    Ott, H.; Roels, S.M.; De Kloe, K.

    2015-01-01

    Drying and salt precipitation in geological formations can have serious consequences for upstream operations in terms of injectivity and productivity. Here we investigate the consequences of supercritical CO2 injection in sandstones. The reported findings are directly relevant for CO2 sequestration

  16. Microbial biofilms on the sandstone monuments of the Angkor Wat Complex, Cambodia.

    Science.gov (United States)

    Gaylarde, Christine C; Rodríguez, César Hernández; Navarro-Noya, Yendi E; Ortega-Morales, B Otto

    2012-02-01

    Discoloring biofilms from Cambodian temples Angkor Wat, Preah Khan, and the Bayon and West Prasat in Angkor Thom contained a microbial community dominated by coccoid cyanobacteria. Molecular analysis identified Chroococcidiopsis as major colonizer, but low similarity values (sandstone. Such analyses are important prerequisites to the application of control strategies.

  17. Continuity and internal properties of Gulf Coast sandstones and their implications for geopressured energy development. Annual report, November 1, 1980-October 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Morton, R.A.; Ewing, T.E.; Tyler, N.

    1982-06-01

    Systematic investigation, classification, and differentiation of the intrinsic properties of genetic sandstone units that typify many geopressured geothermal aquifers and hydrocarbon reservoirs of the Gulf Coast region are provided. The following are included: structural and stratigraphic limits of sandstone reservoirs; characteristics and dimensions of Gulf Coast Sandstones; fault compartment areas; comparison of production and geologic estimates of aquifer volume; geologic setting and reservoir characteristics, wells of opportunity; internal properties of sandstones and implications for geopressured energy development. (MHR)

  18. Proposed moduli of dry rock and their application to predicting elastic velocities of sandstones

    Science.gov (United States)

    Lee, Myung W.

    2005-01-01

    Velocities of water-saturated isotropic sandstones under low frequency can be modeled using the Biot-Gassmann theory if the moduli of dry rocks are known. On the basis of effective medium theory by Kuster and Toksoz, bulk and shear moduli of dry sandstone are proposed. These moduli are related to each other through a consolidation parameter and provide a new way to calculate elastic velocities. Because this parameter depends on differential pressure and the degree of consolidation, the proposed moduli can be used to calculate elastic velocities of sedimentary rocks under different in-place conditions by varying the consolidation parameter. This theory predicts that the ratio of P-wave to S-wave velocity (Vp/Vs) of a dry rock decreases as differential pressure increases and porosity decreases. This pattern of behavior is similar to that of water-saturated sedimentary rocks. If microcracks are present in sandstones, the velocity ratio usually increases as differential pressure increases. This implies that this theory is optimal for sandstones having intergranular porosities. Even though the accurate behavior of the consolidation parameter with respect to differential pressure or the degree of consolidation is not known, this theory presents a new way to predict S-wave velocity from P-wave velocity and porosity and to calculate elastic velocities of gas-hydrate-bearing sediments. For given properties of sandstones such as bulk and shear moduli of matrix, only the consolidation parameter affects velocities, and this parameter can be estimated directly from the measurements; thus, the prediction of S-wave velocity is accurate, reflecting in-place conditions.

  19. Mechanical compaction in Bleurswiller sandstone: effective pressure law and compaction localization

    Science.gov (United States)

    Baud, Patrick; Reuschlé, Thierry; Ji, Yuntao; Wong, Teng-fong

    2016-04-01

    We performed a systematic investigation of mechanical compaction and strain localization in Bleurswiller sandstone of 24% porosity. 70 conventional triaxial compression experiments were performed at confining pressures up to 200 MPa and pore pressures ranging from 5 to 100 MPa. Our new data show that the effective pressure principle can be applied in both the brittle faulting and cataclastic flow regimes, with an effective pressure coefficient close to but somewhat less than 1. Under relatively high confinement, the samples typically fail by development of compaction bands. X-ray computed tomography (CT) was used to resolve preexisting porosity clusters, as well as the initiation and propagation of the compaction bands in deformed samples. Synthesis of the CT and microstructural data indicates that there is no casual relation between collapse of the porosity clusters in Bleurswiller sandstone and nucleation of the compaction bands. Instead, the collapsed porosity clusters may represent barriers for the propagation of compaction localization, rendering the compaction bands to propagate along relatively tortuous paths so as to avoid the porosity clusters. The diffuse and tortuous geometry of compaction bands results in permeability reduction that is significantly lower than that associated with compaction band formation in other porous sandstones. Our data confirm that Bleurswiller sandstone stands out as the only porous sandstone associated with a compactive cap that is linear, and our CT and microstructural observation show that it is intimately related to collapse of the porosity clusters. We demonstrate that the anomalous linear caps and their slopes are in agreement with a micromechanical model based on the collapse of a spherical pore embedded in an elastic-plastic matrix that obeys the Coulomb failure criterion.

  20. Effect of specimen size on energy dissipation characteristics of red sandstone under high strain rate

    Institute of Scientific and Technical Information of China (English)

    Li Ming; Mao Xianbiao; Lu Aihong; Tao Jing; Zhang Guanghui; Zhang Lianying; Li Chong

    2014-01-01

    In this experiment, red sandstone specimens, having slenderness ratios of 0.5, 0.7, 0.9 and 1.1 respec-tively, were subjected to blow tests using a Split Hopkinson Pressure Bar (SHPB) system at a pressure of 0.4 atmospheres. In this paper, we have analyzed the effect of slenderness ratio on the mechanical properties and energy dissipation characteristics of red sandstone under high strain rates. The processes of compaction, elastic deformation and stress softening deformation of specimens contract with an increase in slenderness ratio, whilst the nonlinear deformation process extends correspondingly. In addi-tion, degrees of damage of specimens reduced gradually and the type of destruction showed a transfor-mation trend from stretching failure towards shear failure when the slenderness ratio increased. A model of dynamic damage evolution in red sandstone was established and the parameters of the constitutive model at different ratios of length to diameter were determined. By comparison with the experimental curve, the accuracy of the model, which could reflect the stress-strain dynamic characteristics of red sandstone, was verified. From the view of energy dissipation, an increase in slenderness ratio of a specimen decreased the proportion of energy dissipation and caused a gradual fall in the capability of energy dissipation during the specimen failure process. To some extent, the study indicated the effects of slenderness ratios on the mechanical properties and energy dissipation characteristics of red sandstone under the high strain rate, which provides valuable references to related engineering designs and academic researches.

  1. Investigated Miscible CO2 Flooding for Enhancing Oil Recovery in Wettability Altered Chalk and Sandstone Rocks

    Energy Technology Data Exchange (ETDEWEB)

    Tabrizy, Vahid Alipour

    2012-07-01

    The thesis addresses oil recovery by miscible CO2 flooding from modified sandstone and chalk rocks. Calcite mineral surface is modified with stearic acid (SA) and asphaltene, and the silicate mineral surfaces are modified with N,N-dimethyldodecylamine (NN-DMDA) and asphaltene. The stability of adsorbed polar components in presence of SO4 2- and Mg2 + ions is also investigated. Recovery from sandstone cores is consistently lower than that from chalk cores saturated with the same oil and flooded with CO2 at all miscible flooding conditions. This may be due to the larger permeability contrasts in sandstone cores, which promote the fingering phenomenon. Miscible CO2 flooding for chalk and sandstone cores with distilled water, as initial water saturation, shows also lower oil recovery than cores saturated with different ions. At higher miscible flooding conditions, higher oil recovery is obtained. However, presence of light components (such as C1 or C3) in oil reduced the recovery. Oil recovery in presence of methane (C1) is lower than that in presence of methane and propane (C1/C3). A ternary diagram was constructed in order to understand the CO2 flooding mechanism(s) at the different flooding conditions and in presence of light components. The side effect of the flooding with CO2 is the probability for asphaltene deposition. An approach based on solubility parameter in the liquid, is used to assess the risk for asphaltene deposition during CO2 miscible flooding. The light components (C1/C3) and higher flooding conditions enhanced the risk for asphaltene instability. It is also shown higher amount of asphaltene deposition in chalk cores than that in sandstone cores at similar miscibility conditions.(au)

  2. Elemental Gains/Losses Associated with Alteration Fractures in an Eolian Sandstone, Gale Crater, Mars

    Science.gov (United States)

    Ming, D. W.; Yen, A. S.; Gellert, R.; Sutter, B.; Berger, J. A.; Thompson, L. M.; Schmidt, M. E.; Morris, R. V.; Treiman, A. H.

    2016-01-01

    The Mars Science Laboratory rover Curiosity has traversed up section through approximately 100 m of sedimentary rocks deposited in fluvial, deltaic, lacustrine, and eolian environments (Bradbury group and overlying Mount Sharp group). The Stimson formation unconformably overlies a lacustrine mudstone at the base of the Mount Sharp group and has been interpreted to be a cross-bedded sandstone of lithified eolian dunes. Unaltered Stimson sandstone has a basaltic composition similar to the average Mars crustal composition, but is more variable and ranges to lower K and higher Al. Fluids passing through alteration "halos" adjacent to fractures have altered the chemistry and mineralogy of the sandstone. Elemental mass gains and losses in the alteration halos were quantified using immobile element concentrations, i.e., Ti (taus). Alteration halos have elemental gains in Si, Ca, S, and P and large losses in Al, Fe, Mn, Mg, Na, K, Ni, and Zn. Mineralogy of the altered Stimson is dominated by Ca-sulfates, Si-rich X-ray amorphous materials along with plagioclase feldspar, magnetite, and pyroxenes. The igneous phases were less abundant in the altered sandstone with a lower pyroxene/plagioclase feldspar. Large elemental losses suggest acidic fluids initially removed these elements (Al mobile under acid conditions). Enrichments in Si, Ca, and S suggest secondary fluids (possibly alkaline) passed through these fractures leaving behind X-ray amorphous Si and Ca-sulfates. The mechanism for the large elemental gains in P is unclear. The geochemistry and mineralogy of the altered sandstone suggests a complicated diagenetic history with multiple episodes of aqueous alteration under a variety of environmental conditions (e.g., acidic, alkaline).

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

    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.

  4. Missile impact on structural members

    International Nuclear Information System (INIS)

    In this paper, a unified methodology will be developed to evaluate impact effects of hard missiles on reinforced concrete and steel members including plates/walls and beams. The solution will be investigated based on two ultimate limit states: local perforation and structural collapse of flexible plates and beams

  5. Member Takes Action Against Violence.

    Science.gov (United States)

    Bertholf, Deedrick

    1999-01-01

    An ASBO member and chair of New York's School Emergency Response to Violent Events (SERVE) explains how this program tackles violence and teen suicide. SERVE teaches the basic principles of hostage situations, uses a confidential reporting system, and advocates safety audits and risk-reduction strategies. (MLH)

  6. Finite Element Modeling of the Effect of Cementation on Mohr Coulomb Failure Criteria for Tensleep Sandstone, Alcova Anticline, Wyoming

    Science.gov (United States)

    Busetti, S.; Hennings, P.; Ramos, R.

    2011-12-01

    We simulated rock mechanics tests to model the effect of cementation on the Mohr Coulomb failure parameters of reservoir rock. Experiments show that lithologic variations affect both elastic and inelastic constitutive behavior. To understand controls on inelastic parameters we combined finite element (FE) modeling, a powerful technique that can solve for complex mechanical processes under realistic in-situ conditions, with observations of mineralogy and rock mechanics experiments on Tensleep sandstone, Alcova anticline, Wyoming. Here we present findings on the effect of cement volume % (Vc) on Mohr Coulomb (MC) parameters of internal angle of friction (φ), cohesion (C0), and unconfined compressive strength (UCS). The FE model is of a 1" diameter by 2" long cylindrical plug loaded in axisymmetric triaxial compression. Heterogeneity is defined by randomly assigning each element in the plug one of two MC constitutive definitions based on typical mechanical properties for Tensleep sandstone. The rock is a subarkose sandstone with Vc ranging from 9.5-15.4% increasing from an undeformed area to the limbs and crest of Alcova anticline. In the FE model different values of either φ (45° or 55°) or C0 (20 MPa or 40 MPa), representing weakly or well cemented rock, are assigned to each element for a range of Vc while all other elastic constants and failure parameters remain constant. Steel platens with frictional contact bound the sample, confining pressure is set at either 10 or 35 MPa, and then axial loading is applied until failure. Axial stress-strain plots are used to derive overall MC parameters. Preliminary FE results generally agree with laboratory data and indicate that MC parameters scale with amount of cementation. The Tensleep data indicates quartz overgrowth cementation correlates positively to strengthening, where φ and C0 increase moderately (33°-52°; 24-39 MPa), and UCS nearly doubles (100-188 MPa). FE results show that overall yield stress scales with

  7. Current status and prospects of uranium geology developments of foreign in-situ leachable sandstone type uranium deposits

    International Nuclear Information System (INIS)

    Firstly, with emphasis on in-situ leachable sandstone-type uranium deposits, the prospecting history of uranium deposits worldwide and its scientific research development are generally reviewed in four steps, and their basic historical experience is also summarized. Secondly, based on the detailed description of current development status of uranium geology of foreign in-situ leachable sandstone-type uranium deposits the important strategic position of sandstone-type uranium deposits in overall uranium resources all-over-the-world and its classification, spatial-temporal distribution and regulation, and metallogenic condition of sandstone-type uranium deposits are analysed thoroughly in five aspects: techtonics, paleo-climate, hydrogeology, sedimentary facies and lithology, as well as uranium sources: Afterwards, evaluation principles of three type of hyper-genic, epigenetic infiltrated sandstone-type uranium deposits are summarized. Based on sandstone-type uranium deposits located two important countries: the United States and Russia, the current development status of prospecting technology for in-situ leachable sandstone-type uranium deposits in foreign countries is outlined. Finally, according to the prospects of supply-demand development of global uranium resources, the author points out seriously that Chinese uranium geology is faced with a severe challenge, and proposes directly four strategic measures that should be taken

  8. Dietary Factors Associated To Obesity In Ahwaz Primary School Pupils

    OpenAIRE

    Dorosty A.R; Tabatabaei M

    2005-01-01

    Background: Increase in obesity prevalence in recent years are associated to genetics as well environmental and behavioral factors. Change in dietary patterns including fatty and high density energy foods consumption have been reported to be very important. This study aimed to determine dietary factors (daily energy and macronutrient intakes, energy percentage of macronutrient, energy and macronutrient intakes per kilogram body weight, frequency of cola, natural fruit juice drinking, dairy pr...

  9. Diagenesis and Provenance of Lati Sandstones in the Berau Area, East Kalimantan Province, based on Petrography Data

    Directory of Open Access Journals (Sweden)

    Sigit Maryanto

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v7i3.143This study is focused on the provenance and diagenetic processes affecting the sandstones of Lati Formation cropping out at Berau Area, East Kalimantan Province. Petrographic analysis of twenty-two samples from this formation shows that these sandstones are classified as litharenite, feldspathic litharenite, sublitharenite, feldspathic wacke, and lithic wacke, which are partially calcareous. Preserved diagenetic processes were visible on the petrographic analysis including cementation, replacement, dolomitization, compaction, and dissolution. The provenance of these sandstones is dominated by granitic rocks initiated from tectonic setting of rifted continental margin, transported toward southeast.

  10. Permeability in Rotliegend gas sandstones to gas and brine as predicted from NMR, mercury injection and image analysis

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Fabricius, Ida Lykke; Fisher, Quentin;

    2015-01-01

    Permeability characterisation of low permeability, clay-rich gas sandstones is part of production forecasting and reservoir management. The physically based Kozeny (1927) equation linking permeability with porosity and pore size is derived for a porous medium with a homogeneous pore size, whereas...... the pore sizes in tight sandstones can range from nm to μm. Nuclear magnetic resonance (NMR) transverse relaxation was used to estimate a pore size distribution for 63 samples of Rotliegend sandstone. The surface relaxation parameter required to relate NMR to pore size is estimated by combination of NMR...

  11. Structural and lithological guidance on speleogenesis in quartz-sandstone: Evidence of the arenisation process

    Science.gov (United States)

    Sauro, Francesco

    2014-12-01

    A detailed petrographic, structural and morphometric investigation of different types of caves carved in the quartz-sandstones of the “tepui” table mountains in Venezuela has allowed identification of the main speleogenetic factors guiding cave pattern development and the formation of particular features commonly found in these caves, such as funnel-shaped pillars, pendants and floor bumps. Samples of fresh and weathered quartz-sandstone of the Mataui Formation (Roraima Supergroup) were characterised through WDS dispersive X-ray chemical analyses, picnometer measurements, EDAX analyses, SEM and thin-section microscopy. In all the caves two compositionally different strata were identified: almost pure quartz-sandstones, with content of silica over 95% and high primary porosity (around 4%), and phyllosilicate-rich quartz-sandstone, with contents of aluminium over 10% and low primary porosity (lower than 0.5%). Phyllosilicates are mainly pyrophyllite and kaolinite. SEM images on weathered samples showed clear evidence of dissolution on quartz grains to different degrees of development, depending on the alteration state of the samples. Grain boundary dissolution increases the rock porosity and gradually releases the quartz grains, suggesting that arenisation is a widespread and effective weathering process in these caves. The primary porosity and the degree of fracturing of the quartz-sandstone beds are the main factors controlling the intensity and distribution of the arenisation process. Weathering along iron hydroxide or silt layers, which represent inception horizons, or a strata-bounded fracture network, predisposes the formation of horizontal caves in specific stratigraphic positions. The loose sands produced by arenisation are removed by piping processes, gradually creating anastomosing open-fracture systems and forming braided mazes, geometric networks or main conduit patterns, depending on the local lithological and structural guidance on the weathering

  12. The impact of additives found in industrial formulations of TCE on the wettability of sandstone.

    Science.gov (United States)

    Harrold, Gavin; Lerner, David N; Leharne, Stephen A

    2005-11-01

    The wettability of aquifer rocks is a key physical parameter which exerts an important control on the transport, residual trapping, distribution and eventual fate of chlorinated hydrocarbon solvents (CHSs) released into the subsurface. Typically chlorinated solvents are assumed to be non-wetting in water saturated rocks and unconsolidated sediments. However industrially formulated solvent products are often combined with basic additives such as alkylamines to improve their performance; and the mineral surfaces of aquifer rocks and sediments usually possess a range of acid and hydrogen-bonding adsorption sites. The presence of these sites provides a mechanism whereby the basic additives in CHSs can be adsorbed at the solvent phase/solid phase interface. Given the amphiphilic molecular structure of these additives, this may result in changes in the wetting conditions of the solid phase. The aim of this study was therefore to test this conjecture for two classes of additives (alkylamines and quaternary ammonium salts) that are often encountered in industrial solvent formulations. Wettability assessments were made on sandstone cores by means of measurements of spontaneous and forced water drainage and spontaneous and forced water imbibition and through contact angle measurements on a smooth quartz surface. No solvent/additive combination produced solvent wetting conditions, though dodecylamine and octadecylamine significantly reduced the water wetting preference of sandstone which frequently resulted in neutral wetting conditions. The large volume of spontaneous water drainage observed in wettability experiments involving cetyltrimethylammonium bromide and octadecyltrimethylammonium bromide, suggested that the sandstone cores in these tests remained strongly water wetting. However equilibrium static contact angles of around 60 degrees were measured on quartz suggesting that the sandstone surfaces should be close to neutral wetting conditions. This paradox was finally

  13. Toothbrush contamination in family members

    OpenAIRE

    Adolfo Contreras; Roger Arce; Javier Enrique Botero; Adriana Jaramillo; Marisol Betancourt

    2010-01-01

    Objective: The purpose of this study was to determine the bacterial contamination of toothbrushes in family members. Materials and Methods: One hundred and two healthy subjects were included in this descriptive study. Every individual was examined clinically and microbiologically using the CPITN index and collecting subgingival plaque samples. Each participant received a toothbrush for home use and after one month they returned it to the investigators. All toothbrushes were cultured to determ...

  14. ASCLS members perceptions regarding research.

    Science.gov (United States)

    Mundt, Lillian; Shanahan, Kristy

    2009-01-01

    One of the benchmarks of a profession is performing, publishing, and presenting research. However, in the Clinical Laboratory Science (CLS) profession, few manuscripts are submitted to the American Society for Clinical Laboratory Science (ASCLS) journal, Clinical Laboratory Science, on a regular basis. The problem is that perceptions regarding research, and the role of laboratory professional as researchers, held by ASCLS members may be contributing to the low number of manuscript submissions. To assess these perceptions, an anonymous Likert-scale survey was developed and delivered online using Survey Monkey. Members of ASCLS, with email addresses, were chosen to participate in this survey because they may be most likely to contribute manuscripts for a journal by their own society. About 10% of the 7,000 members who were invited by email chose to participate in this study. Most participants agreed that 1) there is important information to be gathered from research on clinical laboratory specimen results (99.6%), 2) research contributes valuable information to the body of CLS knowledge (99.2%), and 3) conducting research is one of the benchmarks of a profession (92.4%). The majority of participants felt that there are inadequate resources (68.8%) and not enough time (83%) available to conduct research in the clinical laboratory setting. Most participants recognize that many laboratory activities constitute research (86.2%), but only a few are willing to publish research findings on their own (29.2%). Those who are the most likely to publish research findings include men, university faculty, and members who are over 60 years old. University faculty are the most likely to assist others in the writing process. These results show an opportunity exists for ASCLS to foster collaborations between bench technologists and educators willing to assist with the publication process.

  15. Shielding member for thermonuclear device

    International Nuclear Information System (INIS)

    In a thermonuclear device for shielding fast neutrons by shielding members disposed in a shielding vessel (vacuum vessel and structures such as a blanket disposed in the vacuum vessel), the shielding member comprises a large number of shielding wires formed fine and short so as to have elasticity. The shielding wires are sealed in a shielding vessel together with water, and when the width of the shielding vessel is changed, the shielding wires follow after the change of the width while elastically deforming in the shielding vessel, so that great stress and deformation are not formed thereby enabling to improve reliability. In addition, the length, the diameter and the shape of each of the shielding wires can be selected in accordance with the shielding space of the shielding vessel. Even if the shape of the shielding vessel is complicated, the shielding wires can be inserted easily. Accordingly, the filling rate of the shielding members can be changed easily. It can be produced more easily compared with a conventional spherical pebbles. It can be produced more easily than existent spherical shielding pebbles thereby enabling to reduce the production cost. (N.H.)

  16. Toothbrush contamination in family members

    Directory of Open Access Journals (Sweden)

    Adolfo Contreras

    2010-04-01

    Full Text Available Objective: The purpose of this study was to determine the bacterial contamination of toothbrushes in family members. Materials and Methods: One hundred and two healthy subjects were included in this descriptive study. Every individual was examined clinically and microbiologically using the CPITN index and collecting subgingival plaque samples. Each participant received a toothbrush for home use and after one month they returned it to the investigators. All toothbrushes were cultured to determine the presence of periodontopathic bacteria and enteric rods. Wilkoxon signed rank test and t student test (P d"0.05 were used to compare differences in the subgingival microbiota and toothbrush contamination and CPITN index among family members. Results: A high proportion of toothbrushes resulted highly contaminated with enteric rods (P d"0.001 compared to the subgingival environment where periodontopathic bacteria were more prevalent. The most frequent microorganisms found in toothbrushes used by parents and children for one month were Enterobacteriaceae, Pseudomonadaceae species (>50% and Fusobacterium spp (30%. Conclusions: High levels of enteric rods were commonly detected in toothbrushes used for 1 month among members of the families. These opportunistic organisms may have an important role in oral infections including gingivitis and periodontitis. Monthly replacement or disinfection of the toothbrush can reduce the risk of bacterial transmission/translocation and thus diminish the incidence of biofilm associated oral diseases.

  17. 7 CFR 983.42 - Initial members and nomination of successor members.

    Science.gov (United States)

    2010-01-01

    ... members and nomination of successor members. Nomination of committee members and alternates shall follow...) Successor members. Subsequent to the first nomination of committee members under this part, persons to be nominated to serve on the committee as producer or handler members shall be selected pursuant to...

  18. Fluid identification in tight sandstone reservoirs based on a new rock physics model

    Science.gov (United States)

    Sun, Jianmeng; Wei, Xiaohan; Chen, Xuelian

    2016-08-01

    To identify pore fluids, we establish a new rock physics model named the tight sandstone dual-porosity model based on the Voigt-Reuss-Hill model, approximation for the Xu-White model and Gassmann’s equation to predict elastic wave velocities. The modeling test shows that predicted sonic velocities derived from this rock physics model match well with measured ones from logging data. In this context, elastic moduli can be derived from the model. By numerical study and characteristic analyzation of different elastic properties, a qualitative fluid identification method based on Poisson’s ratio and the S-L dual-factor method based on synthetic moduli is proposed. Case studies of these two new methods show the applicability in distinguishing among different fluids and different layers in tight sandstone reservoirs.

  19. Investigation on the suitability of natural sandstone as a gamma dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, C. [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt)], E-mail: cairosoliman@yahoo.com; Salama, E. [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt)

    2009-10-01

    The suitability of sandstone for the gamma radiation dosimetry using thermoluminescence technique is investigated. Its properties are systematically studied utilizing atomic absorption spectrometry, measurements of natural and laboratory-induced blue thermoluminescence emission band, trap depths and storage effects. The emission of the natural blue-band exhibited broad peak at {approx}315 {sup o}C. The thermoluminescence gamma dose response has a linear behavior over the dose range 1-50 Gy followed by sub-linearity at high dose level, with standard deviation in all cases less than {+-}9%. Trapping depths showed a closely spaced set of traps for both the natural and laboratory-induced glow curves. The variation in thermoluminescence signal over 1 week storage period at room temperature was not more than 7%. The thermoluminescence fading effects were explained by the localized transition model. From our results, it is possible to conclude that natural sandstone is a suitable material for accident and industrial dosimetric applications.

  20. NMR response of non-reservoir fluids in sandstone and chalk.

    Science.gov (United States)

    van der Zwaag, C H; Stallmach, F; Skjetne, T; Veliyulin, E

    2001-01-01

    Transverse (T2) NMR relaxation time at 2 MHz proton resonance frequency was measured on core plug samples from two different lithologies, sandstone and chalk, before and after exposure to selected drilling fluids. The results show that NMR signal response was significantly altered after displacing 50% of the original pore fluids, crude oil and water, by drilling fluid filtrate. Relaxation spectra of the rock samples invaded by water-based filtrate shift to significantly shorter T2-values. This shift yields an underestimation of the free-fluid volumes when selecting cut-off values of 33 ms and 100 ms for sandstone and chalk, respectively. In opposite, rock samples affected by oil-based filtrate respond with a signal indicating significantly larger free-fluid volumes than present before exposure. NMR-permeability calculated based on the Timur-Coates Free Fluid model altered in some cases by one order of magnitude. PMID:11445352

  1. Production of a Porosity Map by Kriging in Sandstone Reservoirs, Case Study from the Sava Depression

    Directory of Open Access Journals (Sweden)

    Tomislav Malvić

    2008-05-01

    Full Text Available Variogram analyses and usages of geostatistical interpolations have been standard analytical tools in Croatian geology in the last five years. Such analyses have especially been applied in the mapping of petroleum geological data. In this paper, spatial modelling of porosity data and, consequently, kriging mapping are described for a relatively large dataset obtained at an oil field located in the Croatian part of Pannonian basin (Sava depression. Analyzed datasets included porosity values measured in a sandstone reservoir of Pannonian age. The original dataset can be considered as a rare extensive porosity set available for Croatian hydrocarbon reservoirs. It made possible very reliable semivariogram modelling and kriging interpolation of porosity. The obtained results point out kriging as the most appropriate interpolation approach for porosity, but also for other geological data in sandstone reservoirs of Miocene age.

  2. Partially restricted diffusion in a permeable sandstone: observations by stimulated echo PFG NMR.

    Science.gov (United States)

    Fordham, E J; Gibbs, S J; Hall, L D

    1994-01-01

    We demonstrate a variant, insensitive to eddy current effects, of an alternating pulsed field gradient technique designed to null the effect of background gradients in liquid-saturated porous media, using a 38 mm diameter sample of a natural sandstone. Measurements of the effective diffusivity confirm predictions of a decline as the square root of an effective diffusion time. A value of the ratio S/Vp for the dominant pores is extracted, yielding with T1 a value for the surface relaxivity. We test also a geometry-dependent data collapse recently suggested for a range of diffusion times and wavenumbers. The data agree with a sheet-like pore model for this granular sandstone, and fail to agree with a tube-like model; a pore length scale is also extracted.

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

    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.

  4. Impact cratering in sandstone: The MEMIN pilot study on the effect of pore water

    Science.gov (United States)

    Kenkmann, Thomas; Wünnemann, Kai; Deutsch, Alexander; Poelchau, Michael H.; Schäfer, Frank; Thoma, Klaus

    2011-06-01

    Planetary surfaces are subjected to meteorite bombardment and crater formation. Rocks forming these surfaces are often porous and contain fluids. To understand the role of both parameters on impact cratering, we conducted laboratory experiments with dry and wet sandstone blocks impacted by centimeter-sized steel spheres. We utilized a 40 m two-stage light-gas gun to achieve impact velocities of up to 5.4 km s-1. Cratering efficiency, ejection velocities, and spall volume are enhanced if the pore space of the sandstone is filled with water. In addition, the crater morphologies differ substantially from wet to dry targets, i.e., craters in wet targets are larger, but shallower. We report on the effects of pore water on the excavation flow field and the degree of target damage. We suggest that vaporization of water upon pressure release significantly contributes to the impact process.

  5. Evaluation on geology-hydrogeology condition of a sandstone type uranium deposit

    International Nuclear Information System (INIS)

    The geology-hydrogeology condition of deposit is one of the most important conditions which decide the feasibility of in-situ leach mining. A sandstone type uranium deposits are found larger sandstone type uranium de- posits in recent years., the 'in-situ leach index' (LI) model is introduced by analysing the ore deposit geology- hydrogeology conditions. Combining with each factor to the influence degree of in-situ leaching mining, each index quantification factors, and attached to the weight, Knowing the value of LI, the suitability of the deposit (block) to be exploited to the in-situ leach mining can be quantitatively assessed. The bigger the LI value, the more favourable the deposit is for in-situ leach mining, and the better the geologic-technologic properties of ores are. The calculation results show that a deposit dip for mining. (authors)

  6. Architecture of an Upper Jurassic barrier island sandstone reservoir, Danish Central Graben:

    DEFF Research Database (Denmark)

    Johannessen, Peter N.; Nielsen, Lars H.; Nielsen, Lars;

    2010-01-01

    sands is puzzling since a barrier island typically migrates landwards during transgression and only a thin succession of back-barrier and shoreface sands is preserved. Investigation of the development and geometry of the Freja reservoir sandstones is problematic since the reservoir is buried c. 5 km...... sandstones. Using the nearest maximum flooding surface above the reservoir as a datum for well-log correlations, the base of the barrier island succession in the wells is reconstructed as a surface with steep, seaward-dipping palaeotopography. The relief is c. 270 m over a distance of c. 8 km and dips WNW...... and is up to 20 m thick. To unravel the internal 3D facies architecture of the island, an extensive ground penetrating radar (GPR) survey of 35 km line length and seven cores, c. 25 m long, was obtained. Although the barrier island experienced a rapid relative sea-level rise, sedimentation kept pace...

  7. Simulation of sandstone degradation using large-scale slake durability index testing device

    Directory of Open Access Journals (Sweden)

    Chaowarin Walsri

    2012-11-01

    Full Text Available Large-scale slake durability index tests have been performed on Khok Kruat (KK, Phu Kradung (PK and Phra Wihan(PW sandstone. A rotating drum with a diameter of 64 cm and length of 40 cm was fabricated to accommodate ten rockfragments with a nominal size of 10 cm. Both large-scale and standard-testing were performed under dry and wet conditions.The large-scale test yields rock deterioration twice greater than the small-scale test, primarily due to the greater energyimposed on the rock fragments. The weight losses under wet condition are 12%, 8%, and 3% greater than under dry condition for KK, PK, and PW sandstones, respectively. After 10 test cycles the water absorption values for PW, KK and PKsandstones are 12%, 3%, and 2%, respectively. Rock degradation under the rapid cooling-heating cycles in the laboratory isabout 18 times faster than under the field condition in the northeast of Thailand.

  8. EDXRF analysis of coal, shale and sandstone from boreholes of Jharia and Ranchi coal field

    International Nuclear Information System (INIS)

    The major and trace element concentrations of relevant elements e.g. Al, Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Pb, Rb and Sr in the coal, shale and sandstone samples collected in boreholes from two coalfields, i.e, Jharia and near Ranchi were estimated by energy dispersive X-ray analysis (EDXRF). The elemental profile in the coal samples reflected the elemental compositions determined in the shale and sandstone. Sulphur level in the coal samples, an important parameter for quality of coal was measured to be 0.93% w/w from Jharia field which was nearly two folds higher than the coal samples from Ranchi (0.5% w/w) area. Some of the trace elements in Ranchi coal were found to be significantly higher than the Jharia coal, which can be attributed to its higher grade and also difference in Provenance. (author)

  9. Multi-element determination of sandstone rock by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    The instrumental neutron activation analysis technique (INAA) was used in the qualitative and quantitative analysis of sandstone samples from Aswan area in South Egypt. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of 7 x 1011 n/cm2.s in the TRIGA Mainz research reactor facilities. Gamma spectra from hyper pure germanium HPGe detector were analysed. The present study provides the basic data of elemental concentrations of sandstone rock. The following elements constituents have been determined: Na, K, Fe, Sc, Cr, Co, Zr, Ce, La, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. The x-ray fluorescence (XRF) was used for comparison and to detect elements which can be detected only by XRF. (author)

  10. Investigation of two phase flow and phase trapping by secondary imbibition within Fontainebleau sandstone.

    Science.gov (United States)

    Holmes, William M; Packer, Ken J

    2003-01-01

    Pulsed magnetic field gradient stimulated echo NMR is used to investigate the simultaneous flow of two phases (an aqueous phase and an hydrocarbon phase) within a strongly water-wet sample of Fontainebleau sandstone. The Fontainebleau sandstone is prepared in increasing steady-state water saturations by a secondary imbibition process. The increase in the water saturation causes an increasing fraction of the oil phase (non-wetting phase) to become trapped within the sample. The stimulated echo dependence on the gradient pulse area, q, is used to derive the displacement probability, PX, for a fixed observation time. These displacement probabilities clearly show the progressive trapping of the hydrocarbon phase with increasing steady-state water saturations. Quantitative measurements of the fraction of the oil phase trapped were made from the echo attenuation function Edelta(q), both as a function of water saturation and observation time.

  11. A Study of Thin Sandstone Reservoirs by High-resolution Seismic Inversion

    Institute of Scientific and Technical Information of China (English)

    Ning Songhua

    2006-01-01

    In this paper seismic inversion was used as a key technique and the seismic wavelet most suitable to the actual underground situation was extracted with the higher-order statistics algorithm. The wavelets extracted in this way and the wavelets extracted with the seismic statistics techniques were used separately for inverting the seismic data of the southern part of Tahe oilfield, Tarim basin. The results showed that the resolution of the wavelet inversion with the higher-order statistics method was greatly improved, and the wavelet-inverted section could better distinguish the thin sandstone reservoirs of the upper and lower Carboniferous and their lateral distribution, providing a reliable basis of analysis for the study of thin sandstone reservoirs.

  12. Dielectric and conductivity measurements as proxy method to monitor contamination in sandstone.

    Science.gov (United States)

    Saltas, V; Vallianatos, F; Soupios, P; Makris, J P; Triantis, D

    2007-04-01

    The present work investigates whether dielectric spectroscopy can be used to detect contamination, which may leach in a natural porous material, due to the spreading of contaminants. For this purpose, dielectric and conductivity measurements, in the frequency range from 10 mHz to 1 MHz, were carried out in sandstone samples, partially filled or saturated with solutions of leachates, at different concentrations. The experimental results suggest the dominant role of free water to the measured electrical conductivity and dielectric permittivity in contaminated samples with high water content. On the other hand, various relaxation mechanisms were observed in dried samples at different leachate concentrations. Experimental data were fitted using the Havriliak-Negami dielectric relaxation function, superimposed with a conductivity term. The determined parameters of the fitting function may serve to distinguish between different amounts of leachate in sandstone samples.

  13. Elemental Geochemistry of the Interlayer Oxidation Zone in the Shihongtan Sandstone Type Uranium Deposit, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    CAI Genqing; ZHANG Zimin; LI Shengxiang

    2005-01-01

    According to the oxidation intensity of ore-hosting sandstone, the interlayer oxidation zone of the Shihongtan sandstone-type uranium deposit in the Turpan-Hami basin can be divided into 4 geochemical subzones, namely, intensely-oxidized, weakly-oxidized, redox and unoxidized primary subzones. The elemental geochemical characteristics of the four subzones have been studied in detail, and the results show that U, together with other elements such as Re, Mo, Se, Sr, S,REE, Corganic etc., is enriched in the redox subzone. Re and U have similar geochemical properties in the reduction-oxidation process. The geochemical properties of Mo and Se are similar to those of U in the reduction condition, but different from those of U in the oxidation condition. It is proposed that the ore-hosting layers can provide a curtain mount of uranium for uranium mineralization.

  14. DETERMINATION OF TECTONIC EVOLUTION OF A SEDIMENTARY BASIN FROM SANDSTONE COMPONENTS

    Institute of Scientific and Technical Information of China (English)

    Lei SHAO; Chuanlian LIU; Karl STATTEGGER

    2001-01-01

    Terrigenous sedimentary rocks are the dominant rock types in continental sedimentary basin, the components of these rocks are mainly controlled by source rocks. Through systematically analyzing the components of terrigenous sedimentary rocks, the tectonic evolution of a sedimentary basin can be reconstructed. The Turpan Basin was examined using sandstone petrological and geochemical methods.The consistency of the petrographical and geochemical results shows that the tectonic evolution of the basin can be subdivided into four stages: the first stage covers the Permian; the second stage the Triassic;the third stage from the Lower Jurassic to Upper Jurassic and the fourth stage from the Cretaceous to Tertiary. The components of sandstones among these stages are different, which reflect the influence of tectonics movements on the evolution of the basin and surrounding areas.

  15. Spatial distribution of epibenthic molluscs on a sandstone reef in the Northeast of Brazil.

    Science.gov (United States)

    Martinez, A S; Mendes, L F; Leite, T S

    2012-05-01

    The present study investigated the distribution and abundance of epibenthic molluscs and their feeding habits associated to substrate features (coverage and rugosity) in a sandstone reef system in the Northeast of Brazil. Rugosity, low coral cover and high coverage of zoanthids and fleshy alga were the variables that influenced a low richness and high abundance of a few molluscan species in the reef habitat. The most abundant species were generalist carnivores, probably associated to a lesser offer and variability of resources in this type of reef system, when compared to the coral reefs. The results found in this study could reflect a normal characteristic of the molluscan community distribution in sandstone reefs, with low coral cover, or could indicate a degradation state of this habitat if it is compared to coral reefs, once that the significantly high coverage of fleshy alga has been recognized as a negative indicator of reef ecosystems health.

  16. Reconstruction of the diagenesis of the fluvial-lacustrine- deltaic sandstones and its influence on the reservoir quality evolution-- Evidence from Jurassic and Triassic sandstones, Yanchang Oil Field, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The reservoir quality of Jurassic and Triassic fluvial and lacustrine-deltaic sandstones of the Yanchang Oil Field in the Ordos Basin is strongly influenced by the burial history and facies-related diagenetic events. The fluvial sandstones have a higher average porosity (14.8%) and a higher permeability (12.7×10?3 ?m2) than those of the deltaic sandstones (9.8% and 5.8 ×10?3 ?m2, respectively). The burial compaction, which resulted in 15% and 20% porosity loss for Jurassic and Triassic sandstones, respectively, is the main factor causing the loss of porosity both for the Jurassic and Triassic sandstones. Among the cements, carbonate is the main one that reduced the reservoir quality of the sandstones. The organic acidic fluid derived from organic matter in the source rocks, the inorganic fluid from rock-water reaction during the late diagenesis, and meteoric waters during the epidiagenesis resulted in the formation of dissolution porosity, which is the main reason for the enhancement of reservoir-quality.

  17. Anatomy of an ancient aeolian sandstone on Mars: the Stimson formation, Gale crater, Mars

    Science.gov (United States)

    Gupta, Sanjeev; Banham, Steven; Rubin, David; Watkins, Jessica; Sumner, Dawn; Grotzinger, John P.; Lewis, Kevin; Edgett, Kenneth S.; Edgar, Lauren; Stack, Kathryn; Day, McKenzie; Ewing, Ryan; Lapotre, Mathieu

    2016-10-01

    Since landing in 2012, the Mars Science Laboratory's (MSL) rover Curiosity has traversed the plains and foothills of Aeolis Mons (informally known as Mt. Sharp) investigating the environments preserved in the stratigraphic record of Gale crater. Recently, the Curiosity team has been investigating the Stimson formation, a sandstone exhibiting abundant crossbedding that drapes the underlying Murray formation mudstones. The contact between the Stimson and underlying Murray formation exhibits several meters relief over several 100 m hundred metres where encountered thus far. The Stimson is observed to onlap onto this contact, indicating that accumulating Stimson sandstones unconformably onlapped or buried local palaeotopography.Facies and architectural elements observed within the Stimson are interpreted to represent deposition within an ancient dune field. The Stimson formation is typically composed of decimeter-scale and meter-scale crossbedded sandstones, (exhibiting wind-ripple lamination and well rounded particles up to granule size). Architectural elements are visible in outcrops oriented perpendicular to the regional northwest dip. These consist of undulating surfaces parallel to the regional dip with observed lateral extents up to 30 m that truncate underlying cross-sets and commonly act as basal surfaces to overlying cross-sets. Undulating surfaces are interpreted possibly to be deflationary supersurfaces, which formed in response to deflation or dune-field stabilisation across a regional extent. Surfaces inclined relative to the regional dip ascend between supersurfaces towards the north east at an observed angle of 3-4°. These surfaces are interpreted to be dune bounding surfaces, which are preserved when dunes climb as a result of dune-field aggradation. Aggradation of the system during the duration of the dune field's existence possibly occurred as a response to episodic increases of sediment supply into the basin, allowing dunes to climb and preserving

  18. Mineral Sequestration of Carbon Dixoide in a Sandstone-Shale System

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tianfu; Apps, John A.; Pruess, Karsten

    2004-07-09

    A conceptual model of CO2 injection in bedded sandstone-shale sequences has been developed using hydrogeologic properties and mineral compositions commonly encountered in Gulf Coast sediments. Numerical simulations were performed with the reactive fluid flow and geochemical transport code TOUGHREACT to analyze mass transfer between sandstone and shale layers and CO2 immobilization through carbonate precipitation. Results indicate that most CO2 sequestration occurs in the sandstone. The major CO2 trapping minerals are dawsonite and ankerite. The CO2 mineral-trapping capacity after 100,000 years reaches about 90 kg per cubic meter of the medium. The CO2 trapping capacity depends on primary mineral composition. Precipitation of siderite and ankerite requires Fe+2 supplied mainly by chlorite and some by hematite dissolution and reduction. Precipitation of dawsonite requires Na+ provided by oligoclase dissolution. The initial abundance of chlorite and oligoclase therefore affects the CO2 mineral trapping capacity. The sequestration time required depends on the kinetic rate of mineral dissolution and precipitation. Dawsonite reaction kinetics is not well understood, and sensitivity regarding the precipitation rate was examined. The addition of CO2 as secondary carbonates results in decreased porosity. The leaching of chemical constituents from the interior of the shale causes slightly increased porosity. The limited information currently available for the mineralogy of natural high-pressure CO2 gas reservoirs is also generally consistent with our simulation. The ''numerical experiments'' give a detailed understanding of the dynamic evolution of a sandstone-shale geochemical system.

  19. Disintegration and Devolatilisation of Sandstone Xenolith in Magmatic Conduits: an Experimental Approach

    OpenAIRE

    Berg, Sylvia

    2010-01-01

    Xenoliths preserve evidence of magma-crust interactions in magmatic reservoirs and conduits. They reveal processes of partial melting of country rock, and disintegration into magma. Widespread evidence for frothy xenoliths in volcanic deposits exists, and these evidently indicate processes of gas liberation, bubble nucleation and bubble growth. This report focuses on textural analysis of frothy sandstone xenoliths from Krakatau in Indonesia, Cerro Negro in Nicaragua, Cerro Quemado in El Salva...

  20. An experimental study of micro-scale deformation in a soft sandstone

    OpenAIRE

    Fonseca, J.; Bésuelle, P.; G. Viggiani

    2013-01-01

    This study investigates the grain scale mechanisms that lead to failure by strain localisation in a slightly cemented sandstone. While the effects of interparticle bonding on the mechanical behaviour of granular geomaterials, including soft rocks, have been largely studied, the physical micro-scale mechanisms governing the material deformation are still poorly understood. In this study, laboratory techniques have been developed to allow a non-invasive investigation of the internal deformation...

  1. The occurrence of biomineralisation products in four lichen species growing on sandstone in western Norway

    OpenAIRE

    Bjelland, Torbjørg; Sæbø, Linda; Thorseth, Ingunn Hindenes

    2002-01-01

    High performance thin-layer chromatography/thin-layer chromatography, X-ray diffraction, and scanning electron microscopy analysis of thallus and lichen-rock interface samples, were undertaken to characterize biomineralization products in Fuscidea cyathoides, Ochrolechia tartarea, Ophioparma ventosa, and Pertusaria coralline, growing on sandstone in western Norway. Whewellite (monohydrate form of Ca oxalate) was found in the thallus of all species, but not in any of the weathering rinds benea...

  2. Numerical simulation of multi-dimensional NMR response in tight sandstone

    Science.gov (United States)

    Guo, Jiangfeng; Xie, Ranhong; Zou, Youlong; Ding, Yejiao

    2016-06-01

    Conventional logging methods have limitations in the evaluation of tight sandstone reservoirs. The multi-dimensional nuclear magnetic resonance (NMR) logging method has the advantage that it can simultaneously measure transverse relaxation time (T 2), longitudinal relaxation time (T 1) and diffusion coefficient (D). In this paper, we simulate NMR measurements of tight sandstone with different wettability and saturations by the random walk method and obtain the magnetization decays of Carr–Purcell–Meiboom–Gill pulse sequences with different wait times (TW) and echo spacings (TE) under a magnetic field gradient, resulting in D-T 2-T 1 maps by the multiple echo trains joint inversion method. We also study the effects of wettability, saturation, signal-to-noise ratio (SNR) of data and restricted diffusion on the D-T 2-T 1 maps in tight sandstone. The results show that with decreasing wetting fluid saturation, the surface relaxation rate of the wetting fluid gradually increases and the restricted diffusion phenomenon becomes more and more obvious, which leads to the wetting fluid signal moving along the direction of short relaxation and the direction of the diffusion coefficient decreasing in D-T 2-T 1 maps. Meanwhile, the non-wetting fluid position in D-T 2-T 1 maps does not change with saturation variation. With decreasing SNR, the ability to identify water and oil signals based on NMR maps gradually decreases. The wetting fluid D-T 1 and D-T 2 correlations in NMR diffusion-relaxation maps of tight sandstone are obtained through expanding the wetting fluid restricted diffusion models, and are further applied to recognize the wetting fluid in simulated D-T 2 maps and D-T 1 maps.

  3. Depositional setting, structural style, and sandstone distribution in three geopressured geothermal areas, Texas Gulf Coast

    Energy Technology Data Exchange (ETDEWEB)

    Winker, C.D.; Morton, R.A.; Ewing, T.E.; Garcia, D.D.

    1981-10-01

    Three areas in the Texas Gulf Coast region with different depositional settings, structural styles, and sandstone distribution were studied with well log and seismic data to evaluate some of the controls on subsurface conditions in geopressured aquifers. Structural and stratigraphic interpretations were made primarily on the basis of well log correlations. Seismic data confirm the log interpretations but also are useful in structure mapping at depths below well control.

  4. Reservoir characteristics of low-permeability sandstones in the Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Byrnes, A.P.

    1997-01-01

    Understanding gas production from low-permeability sandstones requires an understanding of the in situ porosity, brine saturation, and effective gas permeability at reservoir brine saturation. Diagenesis in these sandstones commonly resulted in the destruction of much of the original intergranular porosity and left dissolved grains, clay-filled pores, and sheet-like connecting intergranular pore throats. Pore throats or channels that connect larger pores typically range in size from 1 to 0.1 micron and represent only a small portion of the total porosity. In most low-permeability sandstones, porosity is not significantly changed by confining stress changes, but in situ effective gas permeabilities range from 10 to 1,000 times less than routine air permeability. The influence of confining stress on permeability can be attributed primarily to the decrease in size of the thin, tabular pore throats that connect the larger pores. Under stress, pore throats decrease in diameter by up to 50% to 70% resulting in permeability decreases of 10 to 40 times. Gas effective permeabilities also decrease rapidly to less than 1% of absolute values at water saturations above approximately 40% to 50%. {open_quotes}Irreducible{close_quotes} water saturations increase with decreasing porosity and permeability, and, in sandstones with less than 0.01 md permeability, {open_quotes}irreducible{close_quotes} water saturations increase dramatically. Cumulative flow and storage capacity plots indicate that very thin higher permeability intervals typically yield a large percentage of the cumulative flow capacity. Increased water saturations due to drilling or stimulation result in lower effective gas permeabilities and can unknowingly be stabilized by capillary pressure forces if pore pressures are decreased. This type of formation damage can be remedied by increasing the gas pore pressure to displace mobile water.

  5. The durability of Božanov sandstone – simulation of Prague winter climatic conditions

    OpenAIRE

    Kateřina Kovářová

    2011-01-01

    Sandstones were often used mainly as building material in Prague. Weathering processes lead to deterioration of these dimension stones and to changes in their durability. The range of the deterioration depends on petrography, including internal structure, mineral and matrix composition, and also changes initiated. The stone’s properties are negatively influenced especially during the winter frost period, and the presence of salt can exacerbate this process. The national standardized testing m...

  6. Optical Image Analysis Applied to Pore Network Quantification of Sandstones Under Experimental CO2 Injection

    Science.gov (United States)

    Berrezueta, E.; González, L.; Ordóñez, B.; Luquot, L.; Quintana, L.; Gallastegui, G.; Martínez, R.; Olaya, P.; Breitner, D.

    2015-12-01

    This research aims to propose a protocol for pore network quantification in sandstones applying the Optical Image Analysis (OIA) procedure, which guarantees the measurement reproducibility and its reliability. Two geological formations of sandstone, located in Spain and potentially suitable for CO2 sequestration, were selected for this study: a) the Cretaceous Utrillas unit, at the base of the Cenozoic Duero Basin and b) a Triassic unit at the base of the Cenozoic Guadalquivir Basin. Sandstone samples were studied before and after the CO2 experimental injection using Optical and scanning electronic microscopy (SEM), while the quantification of petrographic changes was done with OIA. The first phase of the rersearch consisted on a detailed mineralogical and petrographic study of the sandstones (before and after CO2-injection), for which we observed thin sections. Later, the methodological and experimental processes of the investigation were focused on i) adjustment and calibration of OIA tools; ii) data acquisition protocol based on image capture with different polarization conditions (synchronized movement of polarizers), using 7 images of the same mineral scene (6 in crossed polarizer and 1 in parallel polarizer); and iii) automated identification and segmentation of pore in 2D mineral images, generating applications by executable macros. Finally, once the procedure protocols had been, the compiled data was interpreted through an automated approach and the qualitative petrography was carried out. The quantification of changes in the pore network through OIA (porosity increase ≈ 2.5%) has allowed corroborate the descriptions obtained by SEM and microscopic techniques, which consisted in an increase in the porosity when CO2 treatment occurs. Automated-image identification and quantification of minerals, pores and textures together with petrographic analysis can be applied to improve pore system characterization in sedimentary rocks. This research offers numerical

  7. Experimental study on the expansive deformation of red sandstone of Hongshanyao

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhen-de(朱珍德); ZHANG Yong(张勇); XING Fu-dong(邢福东); LIU Han-long(刘汉龙)

    2004-01-01

    An experience formula of expansive strain and stone taken from a foundation pit of Hongshanyao Project (HSYP) in Nanjing was described. It is clear that the curve of expansive strain-water content is a logarithm. In the meantime, the relation of expansive strain with time was studied and the importance of expansive stabilization time was illuminated. The experiment results indicated that the water content has a tremendous effect on peak expansive and steady expansive deformation of swelling red sandstone.

  8. Provenance, tectonics and palaeoclimate of Proterozoic Chandarpur sandstones, Chattisgarh basin: A petrographic view

    Indian Academy of Sciences (India)

    Basudeb Datta

    2005-06-01

    Sandstones of early Neoproterozoic Chandarpur Group, Chattisgarh Supergroup, central India display progressive change towards greater textural and mineralogical maturity from base to top of the succession. The clay-silt matrix decreases, sorting of sand grains improves, frequency of rounded grains increases, monocrystalline quartz content increases with concomitant decrease in polycrystalline quartz, feldspar and rock fragments. The trend of variations in different mineralogical and textural attributes, however, exhibits inflections at different stratigraphic levels. The sandstones of the basal Lohardih Formation are alluvial fan deposits, characterized by high matrix and feldspar content, iron-oxide impregnated highly angular grains and poor sorting. Petrographic properties collectively indicate that the sandstones were derived from a weathered granitic crust under a humid climatic condition. Abundance of well rounded grains within the alluvial fan and overlying braided fluvial deposit indicates prolonged wind action during episodes of high aridity. The shallow marine deposit overlying the fluvial deposits in the upper part of the Lohardih Formation exhibits bedto- bed variation in the frequency of angular grains, feldspar content and overall maturity suggesting environmentally controlled segregation of sediments. The abrupt appearance of coarse-grained immature sandstones with concomitant reappearance of iron-oxide impregnated/altered feldspar grains in the upper part of the shelf deposits of the Chaporadih Formation point to a phase of tectonic uplift that possibly triggered a regression. Continued regression and peneplanation heralded the deposition of supermature medium-grained purple quartzarenite of the upper shoreface Kansapathar Formation in the uppermost part of the Chandarpur succession under a hot desertic climatic condition. The provenance analysis revealed that the Chandarpur clastics were derived from granites and granite–gneisses of a continental

  9. Kinetic Modeling of Diagenesis of Eogene Lacustrine Sandstone Reservoirs in the Jianghan Basin, Southeastern China

    Institute of Scientific and Technical Information of China (English)

    倪师军; 卿海若; 唐建武; 周美夫; 李泽琴

    2002-01-01

    In the Tuoshi oilfield, located in the Cenozoic Jianghan Basin of southeastern China, there have been found hydrocarbon reservoirs hosted in lacustrine sandstones of the Eogene Xingouzui Formation. The main diagenetic features identified in these sandstones include the dissolution of detrital K-feldspar and albite grains, the precipitation of quartz as overgrowths and/or cements, and the precipitation and/or transformation of clay minerals. These diagenetic features were interpreted to have occurred in early, intermediate and late stages, based on the burial depth. The kinetics of fluid-mineral reactions and the concentrations of aqueous species at each stage of diagenesis were simulated numerically for these lacustrine sandstones, using a quasi-stationary state approximation that incorporates simultaneous chemical reactions in a time-space continuum. During the early diagenetic stage, pore fluid was weakly acidic, which resulted in dissolution of K-feldspar and albite and, therefore, led to the release of K + , Na + , Al3 + and SiO2(aq) into the diagenetic fluid. The increased K+ , Na + , Al3+ and SiO2(aq) concentrations in the diagenetic fluid caused the precipitation of quartz, kaolinite and illite. At the beginning of the intermediate diagenetic stage the concentration of H + was built up due to the decomposition of organic matter, which was responsible for further dissolution of K-feldspar and albite and precipitation of quartz, kaolinite, and illite. During the late diagenetic stage, the pore fluid was weakly alkaline, K-feldspar became stable and was precipitated with quartz and clay minerals.When the burial depth was greater than 3000 m, the pore fluids became supersaturated with respect to albite, but undersaturated with respect to quartz, resulting in the precipitation of albite and the dissolution of quartz. The diagenetic reactions forecasted in the numerical modeling closely matched the diagenetic features identified by petrographic examination, and

  10. A New Multichelating Acid System for High-Temperature Sandstone Reservoirs

    Directory of Open Access Journals (Sweden)

    Nianyin Li

    2015-01-01

    Full Text Available Sandstone reservoir acidizing is a complex and heterogeneous acid-rock reaction process. If improper acid treatment is implemented, further damage can be induced instead of removing the initial plug, particularly in high-temperature sandstone reservoirs. An efficient acid system is the key to successful acid treatment. High-temperature sandstone treatment with conventional mud acid system faces problems including high acid-rock reaction rate, short acid effective distance, susceptibility to secondary damage, and serious corrosion to pipelines. In this paper, a new multichelating acid system has been developed to overcome these shortcomings. The acid system is composed of ternary weak acid, organic phosphonic chelating agent, anionic polycarboxylic acid chelating dispersant, fluoride, and other assisted additives. Hydrogen ion slowly released by multistage ionization in ternary weak acid and organic phosphonic within the system decreases the concentration of HF to achieve retardation. Chelating agent and chelating dispersant within the system inhibited anodic and cathodic reaction, respectively, to protect the metal from corrosion, while chelating dispersant has great chelating ability on iron ions, restricting the depolarization reaction of ferric ion and metal. The synergic effect of chelating agent and chelating dispersant removes sulfate scale precipitation and inhibits or decreases potential precipitation such as CaF2, silica gel, and fluosilicate. Mechanisms of retardation, corrosion-inhibition, and scale-removing features have been discussed and evaluated with laboratory tests. Test results indicate that this novel acid system has good overall performance, addressing the technical problems and improving the acidizing effect as well for high-temperature sandstone.

  11. Weathering of Pisha-Sandstones in the Wind-Water Erosion Crisscross Region on the Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Two types of pisha-sandstones of purple sandstones and gray sandstones, widely distributing in the wind-water erosion crisscross region of China, were selected and used in laboratory experiments for a better understanding of the drying-wetting-freezing weathering process resulting from the apportionment of water or salt solution to rock samples. Weathering experiments were carried out under the conditions of environment control (including temperature, moisture and salt solution). All rock samples were frequently subjected to 140 drying-wetting-freezing cycles. The influences of weathering process were evaluated. It was found that the different treatments of moisture and salt solution applications could affect the nature of the weathering products resulting from drying-wetting-freezing. It was also observed that salt solution could effectively alleviate the weathering of pisha-sandstones. Although not all the observations could be explained, it was apparent that simulated environmental factors had both direct and indirect effects on the weathering of rocks.

  12. Integrated prediction based on GIS for sandstone-type uranium deposits in the northwest of Ordos Basin

    International Nuclear Information System (INIS)

    The integrated prediction model of sandstone-type uranium deposits and its integrated evaluation methods as well as flow of the work based on GIS are studied. A software for extracting metallogenic information is also developed. A multi-source exploring information database is established in the northwest of Ordos Basin, and an integrated digital mineral deposit prospecting model of sandstone-type uranium deposits is designed based on GIS. The authors have completed metallogenic information extraction and integrated evaluation of sandstone-type uranium deposits based on GIS in the study area. Research results prove that the integrated prediction of sandstone-type uranium deposits based on GIS may further delineate prospective target areas rapidly and improve the predictive precision. (authors)

  13. National Assessment of Oil and Gas Project - Uinta-Piceance Province (020) Depth to the top of the Dakota Sandstone

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset shows depth ranges to the top of the Dakota Sandstone within the Uinta-Piceance Province, northwestern Colorado and northeastern Utah.

  14. Hydrogeology, nav sandstone aquifer, Published in 2009, 1:24000 (1in=2000ft) scale, Washington County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Hydrogeology dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2009. It is described as 'nav sandstone...

  15. Nodular features from Proterozoic Sonia Sandstone, Jodhpur Group, Rajasthan: A litho-biotectonic perspective

    Indian Academy of Sciences (India)

    Arvind Singh; Vikash Anand; Prabhas Pandey; Partha Pratim Chakraborty

    2013-04-01

    The Sonia Sandstone of Proterozoic Jodhpur Group, Marwar Supergroup, exposed around the Sursagar dam area of Jodhpur town, Rajasthan exposes two varieties of nodular features, often spectacular in shape and size. On the basis of mode of occurrence (intra- or interbed) and stratal involvement (single or multiple) the features are classified as Type I and II. From granulometric and microscopic (optical and scanning electron) studies carried out on sandstones from the nodules and their host sandstones, geochemical analysis (SEM-EDAX) of intragranular cement present within Type I nodules, and appreciation of control of associated fracture system within Type II nodules, it is proposed that the two types of nodules vary in their formative mechanism and stage of formation. While Type I nodules are identified as product of processes operative at the early diagenetic, pre-lithification stage, the Type II nodules are undoubtedly the result of post-lithification origin triggered by formation of fracture system. Here we propose generation of vapour pressure (not exceeding the overlying hydrostatic pressure) by decay of thin, laterally impersistent organic mat as the causal factor for intrabed nodule (Type I) formation, which forced rarefication of local grain packing \\tetit {vis-a-vis} early diagenetic silica cementation. The study warrants necessity of more studies on nodules to understand possible roles of organic matter and bedtransgressive fracture systems in their formation, going beyond the generalised secondary mineralization hypothesis.

  16. Rock-Arch Instability Characteristics of the Sandstone Plate under Different Loading Conditions

    Directory of Open Access Journals (Sweden)

    Shuren Wang

    2014-01-01

    Full Text Available Under the concentrated loading and the uniform loading, the tests on the brittle fracture and the hinged arching until the rock-arch instability of the sandstone plate were conducted using self-developed loading device, and the sensitivity of influent factors on the rock-arch failure was analyzed by numerical test based on the particle flow code (PFC. The results showed that sandstone plate instability presented four phases: small deformation elastic stage, brittle fracture arching stage, rock-arch bearing stage, and rock-arch instability stage. Under the uniform loading, the maximum vertical force of the rock-arch instability was much higher than that under the concentrated loading condition, but the maximum lateral force was almost the same. The number of acoustic emission (AE and its positioning results of the sandstone plate showed that the extent of the plate damage under the uniform loading was higher than that under the concentrated loading condition. The friction coefficient effect, size effect, loading rate effect, and the initial horizontal force effect on the rock-arch instability were analyzed by the PFC3D numerical experiment.

  17. Characterization of Petroleum Residue in the Entrada Sandstone, Colorado National Monument

    Science.gov (United States)

    Lillis, Paul G.; King, J. David

    2007-01-01

    Introduction As part of the U.S. Geological Survey's (USGS) petroleum resource assessment of the Uinta-Piceance Province, Colorado and Utah, in 2000 (USGS Uinta-Piceance Assessment Team, 2003), some 170 oils, oil stains, and oil seeps were geochemically characterized and divided into genetic types (Lillis and others, 2003). Recognized oil types include Minturn, Phosphoria, Grassy Trail Creek, Mancos, Mesaverde, and Green River. Subsequent to that study, the existence and general locality of petroleum residue in the Middle Jurassic Entrada Sandstone in Colorado National Monument (CNM) was brought to the attention of the authors (Scott and others, 2001). Because the analysis of such non-commercial petroleum deposits commonly yields valuable regional resource-trend information, we collected and characterized the reported CNM petroleum residue and compared the results with identified oil types in the Uinta-Piceance Province. Three samples of Entrada Sandstone with petroleum residue were collected near Little Park Road along the south edge of the CNM in sec.20, T.12S., R.101W. The approximate extent of the petroleum staining was determined by field testing with solvent, and the stains appear to be restricted to the upper part of the 'board beds' unit (informal name, Scott and others, 2001) of the Entrada Sandstone between the two fault traces of the Glade Park fault.

  18. Intersecting faults and sandstone stratigraphy at the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Vonder Haar, S.; Howard, J.H.

    1980-02-01

    The northwest-southeast trending Cerro Prieto fault is part of a major regional lineament that extends into Sonaro and has characteristics of both a wrench fault and an oceanic transform fault. The distribution of lithologies and temperature within the field was studied by comparing data from well cuttings, cores, well logs, and geochemical analyses. Across the earliest developed portion of the field, in particular along a 1.25-km northeast-southwest section from well M-9 to M-10, interesting correlations emerge that indicate a relationship among lithology, microfracturing, and temperature distribution. In the upper portion of Reservoir A of this stratigraphic section, between 1200 and 1400 m, the percentage of sandstones ranges from 20 to 55. Temperatures are 225/sup 0/ to 275/sup 0/C based on well logs, calcite isotope maxima, and Na-K-Ca indices. The study shows that an isothermal high in this vicinity corresponds to the lowest total percentage of sandstones. Scanning electron microphotographs of well cores and cuttings from sandstone and shale units reveal clogging, mineral dissolution, and mineral precipitation along microfractures. The working hypothesis is that these sandy shale and siltstone facies are most amenable to increased microfracturing and, in turn, such microfracturing allows for higher temperature fluid to rise to shallower depths in the reservoir.

  19. Weak-aeromagnetic anomaly and in-situ leachable sandstone-type uranium deposit

    International Nuclear Information System (INIS)

    Anomaly the information over in-situ leachable sandstone type uranium deposit appears rather weak due to the thick cover, therefore, prospecting in this area is extremely difficult. The purpose of this paper is to search the aerogeophysical prospecting information relative to the formation of in-situ leachable sandstone-type uranium deposit. After careful study of aeromagnetic data of three known deposits No. 510, 511 and 512 in the southern rim of Yili Basin, this paper discovers that there are weak-aeromagnetic anomalies over this deposits, and makes further discussion on the forming mechanism of weak-aeromagnetic anomaly according to the metallogenetic geochemical mechanism of this type uranium deposit. Combining with the practical predictions, it concludes that there are weak-micromagnetic anomalies over in-situ leachable sandstone type uranium deposits related to redox transitional zone, and high precision aeromagnetic survey can detect these anomalies, so weak-aeromagnetic anomaly can be regarded as one of characteristic anomalies for this type deposit and can act as a kind of direct guiding information in the pre-phase metallogenetic prediction. (authors)

  20. Capillarity and wetting of carbon dioxide and brine during drainage in Berea sandstone at reservoir conditions

    Science.gov (United States)

    Al-Menhali, Ali; Niu, Ben; Krevor, Samuel

    2015-10-01

    The wettability of CO2-brine-rock systems will have a major impact on the management of carbon sequestration in subsurface geological formations. Recent contact angle measurement studies have reported sensitivity in wetting behavior of this system to pressure, temperature, and brine salinity. We report observations of the impact of reservoir conditions on the capillary pressure characteristic curve and relative permeability of a single Berea sandstone during drainage—CO2 displacing brine—through effects on the wetting state. Eight reservoir condition drainage capillary pressure characteristic curves were measured using CO2 and brine in a single fired Berea sandstone at pressures (5-20 MPa), temperatures (25-50°C), and ionic strengths (0-5 mol kg-1 NaCl). A ninth measurement using a N2-water system provided a benchmark for capillarity with a strongly water wet system. The capillary pressure curves from each of the tests were found to be similar to the N2-water curve when scaled by the interfacial tension. Reservoir conditions were not found to have a significant impact on the capillary strength of the CO2-brine system during drainage through a variation in the wetting state. Two steady-state relative permeability measurements with CO2 and brine and one with N2 and brine similarly show little variation between conditions, consistent with the observation that the CO2-brine-sandstone system is water wetting and multiphase flow properties invariant across a wide range of reservoir conditions.

  1. Experimental study of anisotropy for Berea Sandstone with image-based evaluation

    Science.gov (United States)

    Jeong, Y.; Yun, T.

    2013-12-01

    The rock anisotropy in internal structure of sedimentary rock governs physical behavior of whole body. Spatial composition of mineral and geometry of fabric contributes the anisotropy of rock, influencing on thermal property and wave propagation in internal structure of rock. Thermal conductivity and Wave velocity are important parameters to rock physical properties correlating other key parameters such as strength and elastic modulus. However, the invisibility of anisotropy of rock makes it hard to characterize the internal structure. In this study, 3D X-ray Computed Tomography is used to reveal the orientation of layer in Berea Sandstone based on statistical approach, SPM (Slicing Plane Method) with respect to the uniformly rotated orientation. This study also represents experimental study of thermal conductivity and elastic wave velocity Berea Sandstone. Divided bar method is conducted to get thermal conductivity of rock and elastic wave velocity is evaluated. Result from the statistical study based on image shows that anisotropic ratio for every orientation has unique value and they are coincides with tendency of layer direction. The uniqueness of thermal conductivity and wave velocity based on experimental study is also discussed. 3D Image of Berea Sandstone Result from SPM

  2. Deformation Field around the Stress Induced Crack Area in Sandstone by the Digital Speckle Correlation Method

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yonghong; MA Shaopeng

    2009-01-01

    The deformation field around sub-cracks was calculated using the digital speckle correlation method,First,the uni-axial compression tests on sandstone samples containing a pre-fabricated fracture were made.Photomicrographs showing the characteristies of the sub-crack development were taken using a scanning electron microscope(SEM).From these photomicrographs,the real-time images showing the initiation,growth and coalescence of sub-cracks and micro.cracks in the sandstone specimens were obtained and the effects of loading leveI as well as grain boundaries on the development of cracks were analyzed.Second,the intensity images of the sandstone specimen surface were captured from the observations of the SEM corresponding to different loading levels.Then correlation computation was carried out for the sequential pairs of intensity images to evaluate the displacement components,as well as the strain field.The results show that the deformation varies in different areas separated by sub-cracks during rock damage processes.

  3. Mixed-Mode Fracture Behavior and Related Surface Topography Feature of a Typical Sandstone

    Science.gov (United States)

    Ren, L.; Xie, L. Z.; Xie, H. P.; Ai, T.; He, B.

    2016-08-01

    The geo-mechanical properties of reservoirs, especially the morphology of the rock surface and the fracture properties of rocks, are of great importance in the modeling and simulation of hydraulic processes. To better understand these fundamental issues, five groups of mixed-mode fracture tests were conducted on sandstone using edge-cracked semi-circular bend specimens. Accordingly, the fracture loads, growth paths and fracture surfaces for different initial mixities of the mixed-mode loadings from pure mode I to pure mode II were then determined. A surface topography measurement for each rough fracture surface was conducted using a laser profilometer, and the fractal properties of these surfaces were then investigated. The fracture path evolution mechanism was also investigated via optical microscopy. Moreover, the mixed-mode fracture strength envelope and the crack propagation trajectories of sandstone were theoretically modeled using three widely accepted fracture criteria (i.e., the MTS, MSED and MERR criterions). The published test results in Hasanpour and Choupani (World Acad Sci Eng Tech 41:764-769, 2008) for limestone were also theoretically investigated to further examine the effectiveness of the above fracture criteria. However, none of these criteria could accurately predict the fracture envelopes of both sandstone and limestone. To better estimate the fracture strength of mixed-mode fractures, an empirical maximum tensile stress (EMTS) criterion was proposed and found to achieve good agreement with the test results. Finally, a uniformly pressurized fracture model was simulated for low pressurization rates using this criterion.

  4. Significance of Lockeia and associated trace fossils from the Bada Bagh Member, Jaisalmer Formation, Rajasthan

    Indian Academy of Sciences (India)

    Amruta R Paranjape; Kantimati G Kulkarni; Shweta S Gurav

    2013-10-01

    A Lockeia-Protovirgularia ichnofauna representing the Cruziana ichnofacies is reported from a calcareous sandstone horizon of the Callovian Bada Bagh Member, Jaisalmer Formation, Rajasthan. The ichnoassemblage is characterized by Lockeia cunctator, L. siliquaria, Protovirgularia ?bidirectionalis, P. rugosa, Ptychoplasma vagans along with Palaeophycus tubularis, P. striatus, Heliophycus isp. And Lophoctenium isp. Use of numerical analysis yielding length to width ratio, slopes and coefficient of determination helps in confirming identification of ichnospecies of Lockeia. Fine morphological details of Lockeia and Protovirgularia, especially sharp and closely spaced chevrons of Protovirgularia, indicate that the substrate in which they were emplaced was stiff, resistant, dewatered and better consolidated. Therefore, it construes that this ichnoassemblage belonging to the classical Cruziana ichnofacies occurs in stiff softground and not a typical softground. Though the ichnofacies of this calcareous sandstone bed indicates low-medium energy condition under subtidal environment of deposition, underlying strata containing Arenicolites, Skolithos and Curvolithus of Skolithos ichnofacies indicate intertidal sandy shore environment with high energy conditions. Thus, it is concluded that this area was undergoing continuous, gradual deepening. However, the percentage of Thalassinoides, Ophiomorpha and Phycodes in the overlying bed is quite high suggesting an increase in the energy conditions resulting from a probable shallowing.

  5. Geological Model of Member 3 of Shahejie Formation Reservoir in Liuzan Oilfield, Eastern Hebei Province

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new geological model of Member 3 of Shahejie Formation reservoir in the Liuzan Oilfield, eastern Hebei Province was constructed by using modern reservoir modeling technology as sequence stratigraphy and conditional simulation combined with traditional geological analysis. The model consists of a stratigraphic framework model, a structural model, a sedimentary model and a reservoir model. The study shows that the reservoir is a relatively integrated nose structure, whose strata can be divided into 4 sets of parasequence, 12 parasequences. The submerged branched channel of fan delta front is the favorable microfacies, which controls the geometric shape and physical properties of reservoir sandstone. Oil is distributed in premium reservoir sandstones at structural high positions. According to the new geological model, not only the geological contradictions appearing during oil field development are resolved, but also the oil-bearing area is enlarged by 2.7km2 and geological reserves increased by 156.9 million tons. The production capacity of the Liuzan Oilfield is increased by 0.27 million tons per year.

  6. Diagenesis and reservoir quality of the Lower Cretaceous Quantou Formation tight sandstones in the southern Songliao Basin, China

    Science.gov (United States)

    Xi, Kelai; Cao, Yingchang; Jahren, Jens; Zhu, Rukai; Bjørlykke, Knut; Haile, Beyene Girma; Zheng, Lijing; Hellevang, Helge

    2015-12-01

    The Lower Cretaceous Quantou Formation in the southern Songliao Basin is the typical tight oil sandstone in China. For effective exploration, appraisal and production from such a tight oil sandstone, the diagenesis and reservoir quality must be thoroughly studied first. The tight oil sandstone has been examined by a variety of methods, including core and thin section observation, XRD, SEM, CL, fluorescence, electron probing analysis, fluid inclusion and isotope testing and quantitative determination of reservoir properties. The sandstones are mostly lithic arkoses and feldspathic litharenites with fine to medium grain size and moderate to good sorting. The sandstones are dominated by feldspar, quartz, and volcanic rock fragments showing various stages of disintegration. The reservoir properties are quite poor, with low porosity (average 8.54%) and permeability (average 0.493 mD), small pore-throat radius (average 0.206 μm) and high displacement pressure (mostly higher than 1 MPa). The tight sandstone reservoirs have undergone significant diagenetic alterations such as compaction, feldspar dissolution, quartz cementation, carbonate cementation (mainly ferrocalcite and ankerite) and clay mineral alteration. As to the onset time, the oil emplacement was prior to the carbonate cementation but posterior to the quartz cementation and feldspar dissolution. The smectite to illite reaction and pressure solution at stylolites provide a most important silica sources for quartz cementation. Carbonate cements increase towards interbedded mudstones. Mechanical compaction has played a more important role than cementation in destroying the reservoir quality of the K1q4 sandstone reservoirs. Mixed-layer illite/smectite and illite reduced the porosity and permeability significantly, while chlorite preserved the porosity and permeability since it tends to be oil wet so that later carbonate cementation can be inhibited to some extent. It is likely that the oil emplacement occurred

  7. Stability assessment of sandstones from the St. Servatius Church in Quedlinburg (UNESCO’s World Heritage Site, Germany)

    OpenAIRE

    Siegesmund, S.; Friedel, C.-H.; Vogel, J; Mosch, S.; Naumann, D; Peter, A.; Giesen, H.

    2010-01-01

    The St. Servatius Church in Quedlinburg (UNESCO’s World Heritage Site, Germany) is characterised by long-standing stability problems and structural damages, which have been known over the last several centuries. The monotonous Cretaceous sandstone with its poor lithification is considered to be the main factor. The sandstone is characterised by a high porosity of around 30 Vol.% (max. ca. 35 Vol.%) and a corresponding high w-value. The porosity and the degree of cementation are responsible fo...

  8. Provenance, diagenesis, tectonic setting and geochemistry of Rudies sandstone (Lower Miocene), Warda Field, Gulf of Suez, Egypt

    Science.gov (United States)

    Zaid, Samir M.

    2012-05-01

    The Lower Miocene Rudies sandstones are important oil reservoirs in the southeastern part, Gulf of Suez basin, Egypt. However, their provenance and diagenesis and their impact in reservoir quality, are virtually unknown. Samples from the Warda field, representing the Lower and Middle Rudies, were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower Rudies sandstones have an average framework composition of Q85F7.2R7.8, and 83% of the quartz grains are monocrystalline. By contrast, the Middle Rudies sandstones are only slightly more quartzose with an average framework composition of Q90F7R3 and 86% of the quartz grains are monocrystalline. Rudies sandstones are mostly quartz arenite with subordinate subarkose and sublithic arenites and their bulk-rock geochemistry support the petrographic results. The modal analysis data of studied samples suggest influence of granitic and metamorphic terrains as the main source rock with a subordinate quartzose recycled sedimentary rocks. The geochemical data interpretation on the basis of discriminate function diagrams reveal the source material was deposited on a passive margin. Textural attributes possibly suggest long-distance transport of grains from the source region and indicates a cratonic or a recycled source. Tectonic setting of Rudies Formation reveals that the lower Rudies sandstones are typically rift sandstone and their deposition constrained the beginning of the faulting, while the middle Rudies sandstones were transported from the far along the rift. Diagenetic features include compaction; dolomite, silica and anhydrite cementation with minor iron-oxide, illite, kaolinite and pyrite cements; dissolution of feldspars, rock fragments. Silica dissolution, grain replacement and carbonate dissolution greatly enhance the petrophysical properties of many sandstone samples.

  9. Petrology and geochemistry of sandstones in the southern Benue Trough of Nigeria: Implications for provenance and tectonic setting

    Institute of Scientific and Technical Information of China (English)

    Minapuye I. Odigi; Levi C. Amajor

    2008-01-01

    Petrographic and geochemical analyses of three Cretaceous lithostratigraphic sandstone units were undertaken to constrain their provenance and tectonic setting. Petrographic analysis showed that there are differences in composition between the three sandstone bodies, which can be attributed to differences in provenance relief, transport distance and geology of the terrain. Composition of the three lithostratigraphic sandstone bodies fall within the craton interior field.Framework mode and chemical features indicated their derivation from basaltic volcanics, source rocks during the early rifting stage, and felsic, intermediate and mafic igneous source rocks located at the southeast basement complex terrain, with minor sedimentary components from the uplifted and folded older Cretaceous strata.The chemical composition of the sandstones is mainly related to source rocks, chemical weathering conditions and transport agents. The source rocks were derived mainly from the southeastern Precambrian basement of Nigeria. Through examination of the sandstones, the tectonic setting was modeled. The Benue Trough belongs to a continental sedimentary basin of the passive margin type.The tectonic evolution from Albian to Maastrichtain of the trough is contributed to the difference in framework mode and chemical composition of the sandstones. The evolution of the basin was reconstructed in terms of sandstone petrology and geochemistry. The tectonic evolution can be subdivided into three stages from the petrology and geochemistry data. The first stage covers Albian; the second stage the Turonian-Coniacian, and the third stage the Campanian-Maastrichtain. These are the three mega discontinuities in the sandstone composition among these three stages. These three discontinuities signify the influence of tectonism.

  10. Late Paleozoic tectonics of the Solonker Zone in the Wuliji area, Inner Mongolia, China: Insights from stratigraphic sequence, chronology, and sandstone geochemistry

    Science.gov (United States)

    Shi, Guanzhong; Song, Guangzeng; Wang, Hua; Huang, Chuanyan; Zhang, Lidong; Tang, Jianrong

    2016-09-01

    The geology in the Wuliji area (including the Enger Us and Quagan Qulu areas) is important for understanding the Late Paleozoic tectonics of the Solonker Zone. Ultramafic/mafic rocks in the Enger Us area, previously interpreted as an ophiolitic suture, are actually lava flows and sills in a Permian turbiditic sequence and a small body of fault breccia containing serpentinite. Subduction zone features, such as accretionary complexes, magmatic arc volcanics or LP/HP metamorphism are absent. Early Permian N-MORB mafic rocks and Late Permian radiolarian cherts accompanied by turbidites and tuffeous rocks indicate a deep water setting. In the Quagan Qulu area, outcrops of the Late Carboniferous to Permian Amushan Formation are composed of volcano-sedimenary rocks and guyot-like reef limestone along with a Late Permian volcano-sedimentary unit. A dacite lava in the Late Permian volcano-sedimentary unit yields a zircon U-Pb age of 254 Ma. The gabbros in the Quagan Qulu area are intruded into the Amushan Formation and caused contact metamorphism of country rocks. Sandstones in the Upper Member of the Amushan Formation contain detrital clasts of volcanic fragments and mineral clasts of crystalline basement rocks (i.e. biotite, muscovite and garnet). Geochemical analysis of volcaniclastic sandstones shows a magmatic affinity to both continental island arc (CIA) and active continental margin (ACM) tectonic settings. A Late Permian incipient rift setting is suggested by analyzing the lithostratigraphic sequence and related magmatism in the Wuliji area. The volcano-sedimentary rocks in the Wuliji area experienced a nearly N-S shortening that was probably related to the Early Mesozoic nearly N-S compression well developed in other areas close to the Wuliji area.

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

    Institute of Scientific and Technical Information of China (English)

    Yang Renchao; Fan Aiping; Han Zuozhen; Wang Xiuping

    2012-01-01

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

  12. Diagenesis characteristics and their influence on Porosity and Permeability of sandstone from Yingcheng Formation in Jinshan field

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ruiyao,GAO Fuhong; ZHANG Zhongyue

    2014-01-01

    In order to understand the diagenesis and its influence on Porosity and Permeability of sandstones from Yingcheng Formation in Jinshan field,aPPlying thin sections,casting and scanning electron microscoPe, the authors studied PetrograPhy,diagenesis,Porosity and Permeability of Yingcheng Formation sandstone reser-voir. The results show that the reservoir of Yingcheng Formation is mainly comPosed of lithic arkoses. Sand-stones exPerienced comPaction,Pressolution,cementation,metasomatism and dissolution. The Primary Pores of the sandstones are undeveloPed;most of Pores are the secondary Pores,which are mainly intragranular dissolu-tion Pores in feldsPar and debris. The comPaction and cementation reduced the Primary Pores in sandstones,the Porosity and Permeability decreased;while the dissolution formed the secondary Pores,resulting in the Porosity and Permeability increase. Due to comPaction and cementation,the Porosity and Permeability are reduced with increasing of dePth. There exists an abnormal enlargement of Porosity and Permeability within a dePth range 2 310-2 450 m. In combination with analysis of Petrology,the dissolution of feldsPar and debris is most deve-loPed in the dePth range. Therefore,comPaction,cementation and dissolution are the imPortant factors which affect the Porosity and Permeability of sandstones.

  13. Basin Dynamics and Sedimentary Infilling of Miocene Sandstone Reservoir Systems In Eastern Tunisian African Margin

    Science.gov (United States)

    Bédir, Mourad; Khomsi, Sami

    2015-04-01

    Most of hydrocarbon accumulations and aquifers within the Cap Bon, Gulf of Hammamet and Sahel basins in eastern tunisian foreland are reservoired within the Upper Miocene Birsa and Saouaf sandstones and shales Formations. In the gulf of Hammamet, these sandstones constitutes oil and gas fields and are exploited on anticline highs and described as varying from shoreface to shallow marine and typically exhibit excellent reservoir quality of 30% to 35% porosity and good permeability from 500 to 1100 md. In addition, the fracturing of faults enhanced the reservoir quality potential. In contrary, the same hydrocarbon reservoirs are important hydrogeologic ones in the Cap Bon and Sahel basins with huge amount of hundred millions of cubic meters of water only partially exploited. Integrated wire line logging correlations, seismic sequence stratigraphic, tectonics and outcrop geologic analogue studies had permitted to highlight the basin structuring and sedimentary environments of sequence deposits infilling of the reservoir distribution between high platforms to subsiding graben and syncline basins bounded by deep-seated transtensive and transpressive flower faults. Seven third order sequence deposits limited by downlap prograding and onlap/toplap aggrading/retrograding system tracts extend along the eastern margin around the three basins by facies and thickness variances. System tracts exhibit around high horst and graben a channelized and levee infillings extending from 100 meters to more than a kilometer of width. They present a stacked single story and multistory channels types showing space lateral and vertical migrations along NE-SW, E-W and N-S directions. Paleogeographic depositional reservoir fair maps distribution highlight deltaic horst domain with floodplain and incised valley of fluvial amalgamed and braided sandstones distributary channels that occupy the high folded horsts. Whereas folded horst-graben and syncline borders domain of Shelf prodelta are

  14. Structural diagenesis in Upper Carboniferous tight gas sandstones. Lessons learned from the Piesberg analog study

    Energy Technology Data Exchange (ETDEWEB)

    Steindorf, P.; Hoehne, M.; Becker, S.; Hilgers, C. [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group (EMR); Koehrer, B. [Wintershall Holding GmbH, Barnstorf (Germany)

    2013-08-01

    Upper Carboniferous tight gas sandstone reservoirs in NW-Germany consist of thick successions of cyclothems. Our focus is the Westphalian D of the Piesberg quarry near Osnabrueck, which exposes cemented, faulted and jointed third-order coarse- to fine-grained sandstone cycles separated by anthracite coal seams. We characterize the rocks and the lateral variation of rock properties such as porosity to better constrain input data for reservoir modelling. Three cycles are exposed, each approximately 50 m thick. Rock types can be clearly distinguished by spectral gamma ray in the quarry. Sandstones are intensely compacted and cemented with quartz and generally characterized by low porosities < 8 % (Hepycnometry on plugs and cuttings). Porosities are secondary and mainly related to detrital carbonate dissolution. Around faults dissolution is higher and the porosities can increase to up to 25%. The normal faults show different throws in the quarry and bands of shale and coal have smeared into the fault at juxtaposed beds, which may result in compartments. They dominantly strike W-E and NNW-SSE, but subordinate NE-SW striking fault patterns are also present. Joints were analyzed in a 50 x 50 m section of the quarry wall using Lidar (Light detection and ranging) laser scanning, which allows the characterization of the lithology and quantitative measurement of bedding and fracture orientation data in inaccessible areas. NNE-SSW and W-E joint sets are accompanied by northeasterly and northwesterly striking sets. Around faults, fault planes and fractures are cemented with quartz veins, showing localized mass transport. Due to the intense cementation, the sandstones can reach uniaxial strengths of more than 100 MPa normal to bedding, and approximately 50 MPa parallel to bedding. Sandstone beds within and close to faults are leached by fluids, and their uniaxial strength is reduced by a factor of more than two. Our high resolution field data enables a better understanding of

  15. Decay of sandstone monuments in Petra (Jordan): Gravity-induced stress as a stabilizing factor

    Science.gov (United States)

    Řihošek, Jaroslav; Bruthans, Jiří; Mašín, David; Filippi, Michal; Schweigstillova, Jana

    2016-04-01

    As demonstrated by physical experiments and numerical modeling the gravity-induced stress (stress in further text) in sandstone massive reduces weathering and erosion rate (Bruthans et al. 2014). This finding is in contrast to common view that stress threatens stability of man-made monuments carved to sandstone. Certain low- levels of gravity-induced stress can in fact stabilize and protect these forms against weathering and disintegration. The purpose of this investigation is to evaluate the effect of the stress on weathering of sandstone monuments at the Petra World Heritage Site in Jordan via field observations, salt weathering experiments, and physical and numerical modeling. Previous studies on weathering of Petra monuments have neglected the impact of stress, but the ubiquitous presence of stress-controlled landforms in Petra suggests that it has a substantial effect on weathering and erosion processes on man-made monuments and natural surfaces. Laboratory salt weathering experiments with cubes of Umm Ishrin sandstone from Petra demonstrated the inverse relationship between stress magnitude and decay rate. Physical modeling with Strelec locked sand from the Czech Republic was used to simulate weathering and decay of Petra monuments. Sharp forms subjected to water erosion decayed to rounded shapes strikingly similar to tombs in Petra subjected to more than 2000 years of weathering and erosion. The physical modeling results enabled visualization of the recession of monument surfaces in high spatial and temporal resolution and indicate that the recession rate of Petra monuments is far from constant both in space and time. Numerical modeling of stress fields confirms the physical modeling results. This novel approach to investigate weathering clearly demonstrates that increased stress decreases the decay rate of Petra monuments. To properly delineate the endangered zones of monuments, the potential damage caused by weathering agents should be combined with stress

  16. Mechanical stratigraphy of deep-water sandstones: insights from a multisciplinary field and laboratory study

    Science.gov (United States)

    Agosta, Fabrizio; di Celma, Claudio; Tondi, Emanuele; Corradetti, Amerigo; Cantalamessa, Gino

    2010-05-01

    Turbidite sandstones found in deep-water fold-and-thrust belts are increasingly exploited as hydrocarbon reservoirs. Within these rocks, the fluid flow is profoundly affected by the complex interaction between primary sedimentological and stratigraphic attributes (i.e, facies, layering, reservoir quality, stacking patterns, bed connectivity and lateral extent) and fracture characteristics (i.e., length, spacing, distribution, orientation, connectivity). Unfortunately, most of these features are at, or below, the resolution of conventional seismic datasets and, for this reason, their identification and localization represent one of the fundamental challenges facing exploration, appraisal and production of the sandstone reservoirs. In this respect, whereas considerable effort has been afforded to a characterization of the sedimentological and stratigraphic aspects of sandstones, detailed analysis of fractures in this type of successions has received significantly less attention. In this work, we combine field and laboratory analyses to assess the possible mechanical control exerted by the rock properties (grain size, intergranualr porosity, and Young modulus), as well as the influence of bed thickness, on joint density in turbidite sandstones. Joints are mode-I fractures occurring parallel to the greatest principle stress axis, which solve opening displacement and do not show evidence of shearing and enhance the values of total porosity forming preferential hydraulic conduits for fluid flow. Within layered rocks, commonly, joints form perpendicular to bedding due to overburden or exhumation. The empirical relation between joint spacing and bed thickness, documented in the field by many authors, has been mechanically related to the stress perturbation taking place around joints during their formation. Furthermore, close correlations between joint density and rock properties have been already established. In this present contribution, we focus on the bed

  17. RESERVOIR CHARACTERIZATION OF UPPER DEVONIAN GORDON SANDSTONE, JACKSONBURG STRINGTOWN OIL FIELD, NORTHWESTERN WEST VIRGINIA

    Energy Technology Data Exchange (ETDEWEB)

    S. Ameri; K. Aminian; K.L. Avary; H.I. Bilgesu; M.E. Hohn; R.R. McDowell; D.L. Matchen

    2001-07-01

    The Jacksonburg-Stringtown oil field contained an estimated 88,500,000 barrels of oil in place, of which approximately 20,000,000 barrels were produced during primary recovery operations. A gas injection project, initiated in 1934, and a pilot waterflood, begun in 1981, yielded additional production from limited portions of the field. The pilot was successful enough to warrant development of a full-scale waterflood in 1990, involving approximately 8,900 acres in three units, with a target of 1,500 barrels of oil per acre recovery. Historical patterns of drilling and development within the field suggests that the Gordon reservoir is heterogeneous, and that detailed reservoir characterization is necessary for understanding well performance and addressing problems observed by the operators. The purpose of this work is to establish relationships among permeability, geophysical and other data by integrating geologic, geophysical and engineering data into an interdisciplinary quantification of reservoir heterogeneity as it relates to production. Conventional stratigraphic correlation and core description shows that the Gordon sandstone is composed of three parasequences, formed along the Late Devonian shoreline of the Appalachian Basin. The parasequences comprise five lithofacies, of which one includes reservoir sandstones. Pay sandstones were found to have permeabilities in core ranging from 10 to 200 mD, whereas non-pay sandstones have permeabilities ranging from below the level of instrumental detection to 5 mD; Conglomeratic zones could take on the permeability characteristics of enclosing materials, or could exhibit extremely low values in pay sandstone and high values in non-pay or low permeability pay sandstone. Four electrofacies based on a linear combination of density and scaled gamma ray best matched correlations made independently based on visual comparison of geophysical logs. Electrofacies 4 with relatively high permeability (mean value > 45 mD) was

  18. Donghe Sandstone Subtle Reservoir Exploration and Development Technology in Hade 4 Oilfield

    Institute of Scientific and Technical Information of China (English)

    SunLongde; ZhouXinyuan; SongWenjie; JiangTongwen; ZhuWeihong; YangPing; NiuYujie; DiHongli

    2004-01-01

    Hade 4 oilfield is located on the Hadexun tectonic belt north of the Manjiaer depression in the Tarim basin, whose main target layer is the Donghe sandstone reservoir, with a burial depth over 5,000m and an amplitude below 34m, at the bottom of the Carboniferous. The Donghe sandstone reservoir consists of littoral facies deposited quartz sandstones of the transgressive system tract, overlapping northward and pinching out. Exploration and development confirms that water-oil contact tilts from the southeast to the northwest with a drop height of nearly 80m. The reservoir, under the control of both the stratigraphic overlap pinch-out and tectonism, is a typical subtle reservoir. The Donghe sandstone reservoir in Hade 4 oilfield also has the feature of a large oil-bearing area (over 130 km2 proved), a small thickness (average efficient thickness below 6m) and a low abundance (below 50)< 104t/km2). Moreover, above the target layer developed a set of igneous rocks with an uneven thickness in the Permian formation, thus causing a great difficulty in research of the velocity field. Considering these features,an combination mode of exploration and development is adopted, namely by way of whole deployment, step-by-step enforcement and rolling development with key problems to be tackled, in order to further deepen the understanding and enlarge the fruits of exploration and development. The paper technically focuses its study on the following four aspects concerning problem tackling. First, to strengthen the collecting, processing and explanation of seismic data, improve the resolution, accurately recognize the pinch-out line of the Donghe sandstone reservoir by combining the drilling materials in order to make sure its distribution law; second, to strengthen the research on velocity field, improve the accuracy of variable speed mapping, make corrections by the data from newlydrilled key wells and, as a result, the precision of tectonic description is greatly improved; third

  19. Members of Parliament on Facebook

    DEFF Research Database (Denmark)

    Sørensen, Mads P.

    at political party meetings and at public meetings and hearings. However, the upcoming of new social media like Facebook provides new, interesting platforms for this conversation. And many opinion makers and scholars have high expectations for the democratic potential of these platforms. The paper examines...... what happens when traditional democratic conversations between citizens and politicians are moved away from the old face-to-face meetings and into Facebook. Through interviews with Danish Members of Parliament (MPs) the paper examines the advantages and disadvantages of online democratic conversations...... on Facebook as experienced by the MPs. The paper builds on a former quantitative mapping of the political conversation activities between Danish MPs and their followers on Facebook (Sørensen, 2015)....

  20. Carbon-Isotope Chemostratigraphy of the Yellow Cat Member of the Cretaceous Cedar Mountain Formation, Utah

    Science.gov (United States)

    Suarez, C. A.; Hatzell, G.; Suarez, M. B.; Salazar-Verdin, J.; Al-Suwaidi, A. H.; Kirkland, J. I.

    2014-12-01

    Paleosols and lacustrine sediments of the Yellow Cat Member (YCM), Cedar Mountain Formation (CMF), Eastern Utah were collected at the "Lake Madsen" (a dominantly lacustrine section) and Doelling's Bowl (a mixed lacustrine/ palustrine/ paleosol section) and analyzed for bulk organic carbon isotopes (δ13Corg) . The YCM is thought to span the Barremian to Aptian based on dinosaur faunal assemblages. Correlation with distinct carbon isotope excursions (CIE) specifically those associated with the Selli Event or OAE 1a would allow insight into the response of terrestrial ecosystems to C-cycle perturbations during the Aptian, and may improve chronostratigraphy. Lake Madsen data ranges between a minimum of -28.5‰ and a maximum of -21.4‰ with an average of ~ -25‰ and shows a stepped negative isotope excursion of -3‰., with three distinct negative steps starting ~ 7.5 m above the Jurassic Morrison Formation and an intervening large positive excursion ~ 4.5 m from the base of the Poison Strip Sandstone (~119Ma) Member of the CMF. Doelling's Bowl data spans a longer vertical distance and ranges from a minimum of -29.0‰ to a maximum of -25.7‰, averages -27.7‰ and is somewhat cyclic in nature. δ13Corg chemostratigraphic profile for Doelling's Bowl poorly correlates to the Lake Madsen section, likely due to recycling of organic C and wet/dry cycles of the palustrine environment. Correlation of the Lake Madsen section to marine δ13CCO3 curve from Cismon Valley of the southern Alps indicates the lower Aptian C-isotope excursions C1 to C6, with the distinctive C3 negative CIE occur at the top of the Yellow Cat Member, therefore documenting a terrestrial manifestation of the CIE associated with OAE1a - Selli Event. This suggests the age of the majority of the Yellow Cat Member is Barremian to lower Aptian and the Barremian-Aptian boundary occurs at the top of the Member ~ 25cm below the base of the Poison Strip Sandstone. Further isotopic analysis of vertebrate

  1. Expulsion of Members by Agricultural Cooperatives

    OpenAIRE

    Copeland, John D.

    1986-01-01

    The relationship between farmer members and their cooperatives is unique, a combination of contract, business, and membership interests. Cooperatives may have occasion to terminate the relationship by expelling a member. This article explore legal authority of cooperatives to expel members, conditions under which expulsion is an acceptable action by cooperatives, and legal consequences of improper expulsion are described, and procedures are suggested to protect member and cooperative interest...

  2. International Focus: Highlighting APPA Members Worldwide

    Science.gov (United States)

    Glazner, Steve, Comp.

    2011-01-01

    While most APPA member institutions are located in the United States and Canada, there are also 45 of member institutions located internationally--from Australia and New Zealand to Southeast Asia to the Middle East to Europe. This article focuses on four of its international members: (1) American University of Kuwait (AUK); (2) American University…

  3. Similarities and Differences between the Sandstone-Hosted Jinding Zn-Pb Deposit and MVT Deposits

    Science.gov (United States)

    Chi, G.; Xue, C.

    2009-05-01

    The Jinding Zn-Pb deposit (Lanping basin, Yunnan, China) is the largest sandstone-hosted Zn-Pb deposit in the world, having a total reserve of approximately 220 Mt of ore grading 6.1% Zn and 1.3 Pb%. The sedimentary rocks in the Lanping basin were formed in continental environments and were subject to strong deformation during the Himalayan orogeny. The orebodies are hosted in Cretaceous and Paleocene sandstones and pebbly sandstones which formed a structural dome (the Jinding dome) near a regional, high- angle normal fault (the Pijiang fault). The ores can be divided into two types, the sandstone-type and breccia- type. The former consists of fine-grained sphalerite-galena-pyrite-marcasite disseminations in sandstones, and the latter includes sphalerite-galena-pyrite-marcasite disseminations in the matrix and celestite-pyrite- marcasite-sphalerite-galena-calcite filling fractures and cavities. Colloform textures are common in the breccia-type ores, which are associated with sand veins or dykes cemented by sulfides. Breccia-type ores commonly contain solid bitumen, and freshly opened sandstone-type ores have an oily smell. Oil inclusions are common in both types of ores. CO2-CH4-light hydrocarbon inclusions were found in celestite, sphalerite, authigenic quartz, and calcite. Homogenization temperatures of aqueous inclusions range from about 60 to 300 degree C, and salinities range from 1 to 25 wt.% NaCl equivalent. There is a trend of decreasing temperature and increasing salinities away from the Pijiang fault. Delta 34S (CDT) of sulfides range from -32 to 0 per mil. Noble gas isotopes of fluid inclusions and Pb isotopes of sulfides indicate both mantle and crustal sources. It is proposed that the mineralization resulted from mixing between a high-temperature, low-salinity, deep-seated fluid and a relatively high-salinity, low-temperature, basinal fluid. The former ascended along the Pijiang fault and spread westward, and the latter migrated before and during

  4. The mineralogical composition of sandstone and its effect on sulphur dioxide deposition

    Directory of Open Access Journals (Sweden)

    Müller, Urs

    2008-06-01

    Full Text Available Air pollutants often accelerate stone deterioration in historical buildings and monuments in urban areas. The pollutants are themselves the products of fossil fuel combustion and intensive farming. While this trend seems to have been curbed by strict emission laws in the European Union, in most developing and emerging countries air pollution is an ongoing process due to increasing energy needs and vehicle traffic. Many factors condition natural stone behaviour with respect to gaseous pollutants. Two of the more prominent of such factors are the composition of the atmosphere and the type of stone. Due to their porosity, sandstones are particularly vulnerable to air pollutant attack. Many of the reactions between non-carbonaceous sandstones and these gases are not well understood, however. The present study aimed to acquire an understanding of the processes and factors governing sandstone behaviour when exposed to sulphur dioxide. Seven different sandstones from southern and eastern Germany were analyzed for the study. The binder composition of the stones varied significantly. They also exhibited completely different behaviour in connection with SO2 sorption. Interestingly, while the amount of SO2 deposited was unrelated to the specific surface area of the sandstones, this parameter was closely correlated to the iron oxide content. Iron oxide phases are believed to act as a catalyst in the oxidation of SO2 to SO3. The type and amount of clay mineral, in turn, was found to have no significant impact on initial SO2 deposition in sandstones.Los contaminantes atmosféricos son con frecuencia responsables de la aceleración de la degradación de la piedra en los edificios y monumentos históricos de las zonas urbanas. Los contaminantes en sí son productos de reacción procedentes de la combustión de los hidrocarburos y de la agricultura intensiva. Dentro de la Comunidad Europea, el avance parece haberse ralentizado mediante restrictivas leyes sobre

  5. Early Cretaceous marine sediments of the Lower Saxony Basin. The Gildehaus Sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Dellepiane, S.; Weiel, D. [Wintershall Holding GmbH, Barnstorf (Germany); Gerwert, D.; Mutterlose, J. [Bochum Univ. (Germany). Inst. fuer Geologie, Mineralogie und Geophysik

    2013-08-01

    During the Early Cretaceous (Berriasian - Aptian) the Lower Saxony Basin (LSB) formed the southernmost extension of the North Sea Basin. Sedimentation patterns of the LSB were controlled by divergent dextral shear movement causing differential subsidence related to early rifting in the North Sea. Up to 2000m of fine grained mudstones accumulated in the basin centre, while marginal marine, coarser grained siliciclastics were deposited along the western and southern margins of the LSB. The western marginal facies, outcropping along the Dutch-German border, is characterised by shallow marine sandstones of Valanginian - Hauterivian age. These units, which are separated by clay rich intervals, include the Bentheim Sdst., the Dichotomites Sdst., the Grenz Sdst., the Noricum Sdst. and the Gildehaus Sdst. These sandstones form a series of overall backstepping units, controlled by a main transgressive trend. Economically important are the Bentheim Sdst. and the Gildehaus Sdst., with a long oil producing history. The Bentheim Sdst. (early Valanginian) has been interpreted as an overall retrograding unit related to an incised valley infill with material mainly coming from the South. Tidal processes dominated the deposition of the Bentheim Sdst. The origin and genesis of the Gildehaus Sdst. (mid Hauterivian) is, however, less well understood. Here we present data from two wells drilled to the Gildehaus Sdst. (Emlichheim oil field) which provide evidence for a two fold subdivision of the unit. A well sorted massive quartz sandstone is followed by an interval composed of reworked coarse clastics of massflow origin. Micropalaeontological evidence suggests a fully marine, hemi-pelagic origin of the mud dominated matrix throughout the Gildehaus Sdst. These findings indicate a depositional environment quite different from that of the Bentheim Sdst. Short termed pulses of substantial input of clastic material from two different sources in the West to Southwest punctuated the overall

  6. Gas compositions and processes in the unsaturated zone of the chalk and triassic sandstone aquifers, England

    International Nuclear Information System (INIS)

    Comparatively little is known about the nature of gas sources, sinks and transport in the unsaturated zone, yet this topic is of importance to a wide range of activities extending from agriculture to the construction industry. The composition of the unsaturated zone atmosphere in two different English aquifer types (Chalk and Triassic sandstone) was investigated by the construction of gas sampling boreholes with depths of up to 25 m. Monitoring took place at approximately 1-2 month intervals over 12-24 months. No significant seasonal variations in gas composition were noted. The following mean concentrations of gases was observed (Chalk, sandstone): N2 (77.7%, 77.7%), O2 (19.5%, 19.8%), CO2 (1.5%, 1.5%), N2O (4.2 ppmv, 2.4 ppmv), CH4 (0.1 ppmv, 0.3 ppmv), and δ13C-CO2 (-25.3 per mille, -19.9 per mille). The factor of 50 increase in CO2 reflects production from soil organic matter, supplemented in the sandstone by some CO2 from acidification or carbonate material. The decrease in O2 of little more than 1% absolute from atmospheric concentration indicates the persistence of oxidizing conditions in both unsaturated zones, and the relatively high concentrations of N2O therefore appear likely to have been derived from nitrification rather than denitrification. The limited magnitude of denitrification processes is further illustrated by N2/Ar and δ15N data. To understand better the rate of movement of gases in the unsaturated zone of a fissured aquifer, a tracer test using SF6 was carried out at the Chalk site. The results indicate a diffusion rate up to 103 times higher than that expected for the Chalk matrix alone. (author)

  7. Blueberries on Earth and Mars: Correlations Between Concretions in Navajo Sandstone and Terra Meridiani on Mars.

    Science.gov (United States)

    Mahaney, W. C.; Milner, M. W.; Netoff, D.; Dohm, J.; Kalm, V.; Krinsley, D.; Sodhi, R. N.; Anderson, R. C.; Boccia, S.; Malloch, D.; Kapran, B.; Havics, A.

    2008-12-01

    Concretionary Fe-Mn-rich nodular authigenic constituents of Jurassic Navajo sandstone (moki marbles) bear a certain relationship to similar concretionary forms ('blueberries') observed on Mars. Their origin on Earth is considered to invoke variable redox conditions with underground fluids penetrating porous quartz-rich sandstone leading to precipitation of hematite and goethite-rich material from solution, generally forming around a central nucleus of fine particles of quartz and orthoclase, recently verified by XRD and SEM-EDS analyses. At the outer rim/inner nucleus boundary, bulbous lobes of fine-grained quartz often invade and fracture the outer rim armored matrix. The bulbous forms are interpreted to result from fluid explusion from the inner concretionary mass, a response to pressure changes accompanying overburden loading. Moki marbles, harder than enclosing rock, often weather out of in situ sandstone outcrops that form a surface lag deposit of varnished marbles that locally resemble desert pavement. The marbles appear morphologically similar to 'blueberries' identified on the martian surface in Terra Meridiani through the MER-1 Opportunity rover. On Earth, redox fluids responsible for the genesis of marbles may have emanated from deep in the crust (often influenced by magmatic processes). These fluids, cooling to ambient temperatures, may have played a role in the genesis of the cemented outer rim of the concretions. The low frequency of fungi filaments in the marbles, contrasts with a high occurrence in Fe-encrusted sands of the Navajo formation [1], indicating that microbial content is of secondary importance in marble genesis relative to the fluctuating influx of ambient groundwater. Nevertheless, the presence of filaments in terrestrial concretions hints at the possibility of discovering fossil/extant life on Mars, and thus should be considered as prime targets for future reconnaissance missions to Mars. 1] Mahaney, W.C., et al. (2004), Icarus, 171, 39-53.

  8. Chemical analysis of black crust on the Angkor sandstone at the Bayon temple, Cambodia

    Science.gov (United States)

    Song, Wonsuh; Oguchi, Chiaki; Waragai, Tetsuya

    2014-05-01

    The Angkor complex is the one of the greatest cultural heritages in the world. It is constructed in the early 12th century, designated as a world cultural heritage by UNESCO in 1992. The temples at the Angkor complex are mainly made of sandstone and laterite. However, due to the tropical climate, plants, lichens and various microorganisms are growing well on the rock surface. Black crusts are also easily found on the stone surface. The 21st technical session of the International Coordinating Committee for the Safeguarding and Development of the Historic Site of Angkor (ICC-Angkor) held in 2012 recommended that to preserve both the biofilms and the forest cover and to prohibit the biocides (chlorine-based) and organic biocides. However, there are many reports that lichens and microorganisms accelerate rock weathering. It is important to clarify that how the biofilm on the Angkor temples affect Angkor sandstones. We sampled Angkor sandstone covered by black crust at the Bayon temple, Angkor complex, and observed the section and the surface of the rock sample by using SEM. Surfaces of the samples are not polished in order to observe the original condition. The samples are coated with gold for 180 seconds. The depth of the black crust is up to 1 mm. Many filamentous materials were found on the black crust. Average energy-dispersive X-ray spectroscopy data of the five areas of ca. 20 μm ×15 μm in the black crusts shows that over 80 % of the filamentous materials are compounds of carbon. It seems that these materials are hyphae. The shape of the hypha is like a thread and its size is few μm in diameter and up to several centimeters in length. Black crusts are consisted of elements and compounds of carbon, Na, Mg, Al, Si, Cl, K, Ca, and Fe. Further research has to be done to find out the better and proper way of conservation for the Angkor complex.

  9. Novel microclimate monitoring and microbial colonisation in sandstones of historic buildings, Glasgow, Scotland

    Science.gov (United States)

    Duthie, L.; Hyslop, E.; Lee, M.; Phoenix, V.; Kennedy, C.

    2009-04-01

    The impact of our changing climate on the historic built environment of Scotland has received surprisingly little attention. Current projections indicate that Scotland will become notably wetter and warmer over the coming decades. Winter temperatures are predicted to increase by 30C with 15% more precipitation, one result should be more aggressive microbial weathering of the sandstone buildings. In order to understand better and to quantify the damage potentially caused, it is necessary to analyse existing microbial populations but also to characterize conditions within building stones, how they change over diurnal and seasonal cycles, and how they differ from external conditions. In this study, temperature, humidity and moisture sensors were inserted at different depths into representative Scottish sandstones to record parameters key to microbial colonisation and organic weathering. Penetration of photosynthetically active radiation has also been measured. The within-stone data were compared to meteorological conditions recorded by an adjacent weather station. These data have then been compared with analysis of the microbial populations at different depths within the stone, using osmium stained polished blocks. Notably, microbes occur up to 7 mm beneath the outer sandstone surface, with community structure differing with depth. Clearly, different communities experience very different conditions within the stone, reflecting trophic structure, light penetration and microclimate. The sensor data confirm that temperature and water availability all vary within the stone and differ considerably with the external environment. We conclude that the warm and humid microclimate within Scottish building stones promotes microbial colonisation and stone decay and both will increase significantly with the changing climate of Scotland and north-west Europe.

  10. Scaling of sub-surface deformation in hypervelocity impact experiments on porous sandstone

    Science.gov (United States)

    Buhl, Elmar; Poelchau, Michael; Dresen, Georg; Kenkmann, Thomas

    2014-11-01

    Two hypervelocity impact experiments into dry sandstone (Seeberger Sandstein, ~ 23% porosity), performed under similar impact conditions but with different projectile sizes, have been analyzed to investigate the size scaling of impact damage. For one experiment a 2.5 mm steel projectile was impacted at 4.8 km s- 1 onto a sandstone cube of 20 cm side length. For the other experiment a 10 mm iron meteorite projectile was impacted at 4.6 km s- 1 onto a sandstone cube of 50 cm side length. The resulting kinetic impact energies of 773 and 42,627 J led to crater cavities of 7600 and 612,000 mm3. Investigation of thin sections along cross-sections through both craters revealed that the same deformation microstructures are present in both experiments. The occurrence of different microstructural patterns was mapped and zones of characteristic deformation were defined. This mapping was used to calculate the volumes of material deformed by specific mechanisms. Comparing the results, normalized to the size of the projectile, showed that the sub-surface damage is very similar in size, volume and geometry for both experiments. Analysis of deformation bands found in both experiments regarding their long axes orientation showed that these features are developed under shear deformation. Particle size distributions (PSD), expressed as power-law fits, were measured to quantify the impact damage. Comparison showed that the decay of the power-law exponents with increasing distance from the impact point source is similar for both experiments. Reconstruction of the loading path allowed to infer the stresses under which distinct deformation microstructures are developed.

  11. Wettability Behavior of Crude Oil-Silica Nanofluids-Sandstone Systems

    Science.gov (United States)

    Bai, Lingyun; Li, Chunyan; Pales, Ashley; Huibers, Britta; Ladner, David; Daigle, Hugh; Darnault, Christophe

    2016-04-01

    Mobilizing and recovering crude oils from geological formations is critical for the management and exploitation of petroleum reservoirs. Nanoparticles, with their unique physico-chemical properties can increase the efficiency of enhanced oil recovery (EOR) by decreasing interfacial tension (IFT) between the oil and aqueous phase systems, and altering rock wettability. Our research examines the potential use of nanoparticles as a means of EOR by studying the influence of silicon oxide (SIO2) nanoparticles on the wettability and interfacial tension of different crude oil-silica nanofluids-sandstone systems. We designed nanofluid treatments to manipulate changes in wettability of Berea and Boise sandstones simulating petroleum reservoir. Experiments were performed to measure the IFT and wettability involving different concentrations of nanoparticles with and without the addition of surfactant to determine which nanofluids produced the most favorable wettability changes for optimal EOR with light crude oil (e.g., West Texas, API: 40), medium crude oil (Prudhoe Bay, API: 28), and heavy crude oil (e.g., Lloydminster, API: 20). We investigated the addition of Tween 20 nonionic surfactant to the nanoparticle dispersions - made from SiO2 nanoparticles - that allows the optimum mobility in porous media through optimization of interfacial tension (IFT) and contact angle, and conducted tests. Batch studies were conducted to measure the IFT and wettability of the nanofluids of different range of nanoparticle concentrations (0-0.1 wt. %) in different reservoir conditions, i.e. brine and brine-surfactant systems made with 5% brine and 2CMC of Tween 20 nonionic surfactants. The dynamic behavior of IFT was monitored using a pendant drop method. Five percent brine-nanoparticle systems containing 0.001 and 0.01 wt.% of nanoparticles resulted in a significant decrease of IFT for light and medium crude oils, while the highest decrease of IFT for heavy crude oil was observed with 0.1 wt

  12. The Saint Martin de Belleville syncline and its uraniferous permian sandstone

    International Nuclear Information System (INIS)

    This dissertation (these de specialite) is a study of the geology of the St.Martin d.B. syncline and the uranium prospect 'le Cochet' in the Carboniferous Brianconnais Zone of Savoy. Stratigraphy and sedimentology: This syncline presents continental detrital sediments ranging from U.Carboniferous to L.Triassic. In the U.Carboniferous, magmatic activity begins with the Moriaz Layers acid volcanics that are considered as a lateral equivalent of the Stephanian Courchevel Conglomerates. In Permian times, parts of an alluvial fan seem to occupy the north of the study area (gray and green conglomeratic sandstone). Southwards these inter-finger with flood plain sediments (red slate) including a locally oolitic limestone. Volcanic detritus is important in the Permian. Tourmalinite pebbles are frequent and seem to be related to the regional Permian magmatism. Albitization of feldspars is general in the Carboniferous and the Permian. The Permo-triassic typically shows microcline bearing dolomitic sandstones. In the Scythian quartzites orthoclase is the dominant feldspar. The quartzites are overlain by L.Triassic evaporites identified by the sulfur isotope ratio of their gypsum. The morphology of the zircons in the sandstones has been investigated using the typological method of J.P. Pupin. Regional Permian magmatism apparently produces volcanics of the calc-alkalic and tholeiitic series as well as a high level granitic intrusion of anatectic origin. The uranium occurrences are strata-bound on a kilometric and hecto-metric scale. They are developed almost exclusively in the gray variety of the Permian sandstones whose gray and red varieties are always barren. Within this unit, the mineralization impregnates irregularly distributed lenses and pods of coal material. Uranium is accompanied by vanadium occurring as roscoelite. The association U-V, of bio-philic character, reflects the concentration in the sedimentary environment and argues for a quite indirect relation with the

  13. The Paleozoic sandstones in Wadi Feiran - El Tor area, Sinai, Egypt

    Science.gov (United States)

    Allam, A.

    The Paleozoic sandstone succession between Wadi Feiran and El-Tor in southwestern Sinai has been subdivided into five distinct lithostratigraphic units: the Lower Cambrian Araba Formation; the Upper Cambrian Naqus Formation; the Lower Carboniferous Abu Durba Formation; the Upper Carboniferous Aheimer Formation and the Permian Qiseib Formation. The present study has also proved that the Paleozoic Earth movements have undergone distinct changes in the sedimentary facies, together with lateral variations in the composition and thickness of strata. The distribution of the sediments and their faunal contents point to the existence of five major phases of sedimentation during the Paleozoic Era.

  14. Isotope geochemistry of ore fluids for the Dongsheng sandstone-type uranium deposit,China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Dongsheng sandstone-type uranium deposit is one of the large-sized sandstone-type uranium deposits discovered in the northern part of the Ordos Basin of China in recent years. Geochemical characteristics of the Dongsheng uranium deposit are significantly different from those of the typical interlayered oxidized sandstone-type uranium ore deposits in the region of Middle Asia. Fluid inclusion studies of the uranium deposit showed that the uranium ore-forming temperatures are within the range of 150-160℃. Their 3He/4He ratios are within the range of 0.02-1.00 R/Ra, about 5-40 times those of the crust. Their 40Ar/36Ar ratios vary from 584 to 1243, much higher than the values of atmospheric argon. The δ18OH2O and δD values of fluid inclusions from the uranium deposit are -3.0‰- -8.75‰ and -55.8‰- -71.3‰, respectively, reflecting the characteristics of mixed fluid of meteoric water and magmatic water. The δ18OH2O and δD values of kaolinite layer at the bottom of the uranium ore deposit are 6.1‰ and -77‰, respectively, showing the characteristics of magmatic water. The δ13CV-PDB and δ18OH2O values of calcite veins in uranium ores are -8.0‰ and 5.76‰, respectively, showing the characteristics of mantle source. Geochemical characteristics of fluid inclusions indicated that the ore-formation fluid for the Dongsheng uranium deposit was a mixed fluid of meteoric water and deep-source fluid from the crust. It was proposed that the Jurassic-Cretaceous U-rich metamorphic rocks and granites widespread in the northern uplift area of the Ordos Basin had been weathered and denudated and the ore-forming elements, mainly uranium, were transported by meteoric waters to the Dongsheng region, where uranium ores were formed. Tectonothermal events and magmatic activities in the Ordos Basin during the Mesozoic made fluids in the deep interior and oil/gas at shallow levels upwarp along the fault zone and activated fractures, filling into U-bearing clastic

  15. COMPOSITION AND PROVENANCE OF GRÖDEN SANDSTONE FROM THE VELEBIT MTS.

    Directory of Open Access Journals (Sweden)

    Vedran Sudar

    2016-02-01

    Full Text Available Six samples of Gröden sandstones (Middle Permian were analysed: Five of them were from Pikovac Creek valley (in the vicinity of Brušane village at Velebit Mts., Croatia and one was from the locus typicus Gröden/Val Gardena (Italy. Based on the micropetrographical characteristics of sandstones, as well as on the modal composition and heavy mineral association, origin of material, weathering index of source rocks, climate and relief in the period of deposition have been supposed. Four samples from Pikovac Creek were petrographicaly determined as lithic greywackes, one as densely packed lithic arenite, while a specimen from Gröden locus typicus represents feldspar greywacke. Lithic greywackes/arenites imply very low maturity and suggest a close proximity of source rocks as well as the active tectonics in the hinterland of the depositional basin. Heavy mineral association in the samples from Pikovac Creek valley, with a large amount of fairly rounded stable grains (zircon, tourmaline and rutile, indicate that clastic material was derived from recycled orogen, and probably from reworked sedimentary rocks. The presence of kyanite and chlorite in the heavy mineral assemblage suggest their origin is from metamorphic rocks. This data assumes that Gröden sandstones from Pikovac Creek were possibly deposited in the fan delta or braided delta depositional environment as a part of a rift system (recycled orogen. The composition of the sample Gröden s. locus typicus (light and heavy mineral fractions suggests the vicinity of magmatic rocks in the source area. All analysed samples are red coloured and have a large amount of limonitized grains in the heavy mineral assemblage, that point to the arid climate at the time of deposition. A weathering index diagram for Pikovac sandstones implies an arid/semiarid climate and high relief of the source area where metamorphic or sedimentary rocks dominate, while an arid/semiarid climate and high relief with

  16. New well architectures assessment for geothermal exploitation of the Triassic sandstones in Paris basin

    OpenAIRE

    Hamm, Virginie; Bouzit, Madjid; Lopez, Simon

    2016-01-01

    International audience; The deep geothermal resource of the center of the Paris basin (Ile-de-France, France) has been exploited since the mid-1980s, the main target being the Dogger limestone aquifer (1,500–2,000 m deep, 55–80°C). Currently, the Triassic sandstone units below the Dogger aquifer are envisaged as new targets. This paper presents a modelling and economic analysis used to assess new well architectures (sub-horizontal, horizontal or multilateral wells) in comparison with standard...

  17. Geochemical characteristics of Dongsheng sandstone-type uranium deposit, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    SUN Yuzhuang; LIU Chiyang; DAI Shifeng; QIN Peng

    2007-01-01

    Generally, sandstone-type uranium deposits can be divided into three zones according to their redox conditions: oxidized zone, ore zone and reduced zone. The Dongsheng uranium deposit belongs to this type. In order to study its geochemical characteristics, 11 samples were taken from the three zones of the Dongsheng uranium deposit. Five samples of them were collected from the oxidized zone, four samples from the ore zone and two samples from the reduced zone. These samples were analyzed using organic and inorganic geochemical methods. The results of GC traces and ICP-MASS indicate that the three zones show different organic and inorganic geochemical characteristics.

  18. Laboratory calibration of the seismo-acoustic response of CO2 saturated sandstones

    Science.gov (United States)

    Siggins, A. F.; Lwin, M.; Wisman, P.

    2009-04-01

    Geological sequestration can be regarded as one of the promising mitigation strategies against the negative effects of atmospheric carbon dioxide on global climate change. Injection of CO2into depleted natural gas reservoirs in particular, sandstone formations at depth with suitable porosity and seals, seems to be a promising scenario for on-land storage. In fact, a demonstration project is currently underway in the Otway Basin in South Eastern Australia under the auspices of the Australian CO2CRC. One of the most useful geophysical remote sensing tools for monitoring sub surface CO2 injection is seismic imaging. Interpretation of seismic data for the quantitative measurement of the distribution and saturations of CO2 in the subsurface requires a knowledge of the effects of CO2as a pore fluid on the seismo-acoustic response of the reservoir rocks. This report describes some recent experiments that we have conducted to investigate this aspect under controlled laboratory conditions at pressures representative of in-situ reservoir conditions. Prior to the availability of core from the actual Otway injection site, two synthetic sandstones were tested ultrasonically in a computer controlled triaxial testing rig under a range of confining pressures and pore pressures representative of in-situ reservoir pressures. These sandstones comprised; (1) a synthetic material with calcite intergranular cement (CIPS) and (2), a synthetic sandstone with silica intergranular cement. Porosities of the sandstones were respectively, 32%,and 33%. Initial testing was carried on the cores at room temperature-dried condition with confining pressures up to 65MPa in steps of 5 MPa. Cores were then flooded with CO2, initially at 6MPa, 22 degrees C, then with liquid phase CO2at pressures from 7MPa to 17 MPa in steps of 5 MPa. Confining pressures varied from 10 MPa to 65 MPa. A limited number of experiments were also conducted in an additional rig at 50oC with supercritical phase CO2. Ultrasonic

  19. STRUCTURAL HETEROGENEITIES AND PALEO FLUID FLOW IN AN ANALOG SANDSTONE RESERVOIR 2001-2004

    Energy Technology Data Exchange (ETDEWEB)

    Pollard, David; Aydin, Atilla

    2005-02-22

    Fractures and faults are brittle structural heterogeneities that can act both as conduits and barriers with respect to fluid flow in rock. This range in the hydraulic effects of fractures and faults greatly complicates the challenges faced by geoscientists working on important problems: from groundwater aquifer and hydrocarbon reservoir management, to subsurface contaminant fate and transport, to underground nuclear waste isolation, to the subsurface sequestration of CO2 produced during fossil-fuel combustion. The research performed under DOE grant DE-FG03-94ER14462 aimed to address these challenges by laying a solid foundation, based on detailed geological mapping, laboratory experiments, and physical process modeling, on which to build our interpretive and predictive capabilities regarding the structure, patterns, and fluid flow properties of fractures and faults in sandstone reservoirs. The material in this final technical report focuses on the period of the investigation from July 1, 2001 to October 31, 2004. The Aztec Sandstone at the Valley of Fire, Nevada, provides an unusually rich natural laboratory in which exposures of joints, shear deformation bands, compaction bands and faults at scales ranging from centimeters to kilometers can be studied in an analog for sandstone aquifers and reservoirs. The suite of structures there has been documented and studied in detail using a combination of low-altitude aerial photography, outcrop-scale mapping and advanced computational analysis. In addition, chemical alteration patterns indicative of multiple paleo fluid flow events have been mapped at outcrop, local and regional scales. The Valley of Fire region has experienced multiple episodes of fluid flow and this is readily evident in the vibrant patterns of chemical alteration from which the Valley of Fire derives its name. We have successfully integrated detailed field and petrographic observation and analysis, process-based mechanical modeling, and numerical

  20. A pterodactyloid pterosaur from the Upper Cretaceous Lapurr sandstone, West Turkana, Kenya.

    Science.gov (United States)

    O'Connor, Patrick M; Sertich, Joseph J W; Manthi, Fredrick K

    2011-03-01

    An isolated pterosaurian caudal cervical (~ postcervical) vertebra was recovered from the Upper Cretaceous Lapurr sandstone of West Turkana, northwestern Kenya. The vertebral centrum is short, wide, and dorsoventrally compressed. Although the specimen is lightly built similar to most pterosaurs, it is here referred to Pterodactyloidea and tentatively to the Azhdarchidae in that it lacks pneumatic features on both the centrum and neural arch. This represents one of the few pterosaurs recovered from the entirety of Afro-Arabia, the first pterosaur recovered from the Cretaceous of East Africa, and, significantly, a specimen that was recovered from fluvial deposits rather than the near-shore marine setting typical of most pterosaur discoveries.

  1. Biotic and abiotic anaerobic transformations of trichloroethene and cis-1,2-dichloroethene in fractured sandstone.

    Science.gov (United States)

    Darlington, Ramona; Lehmicke, Leo; Andrachek, Richard G; Freedman, David L

    2008-06-15

    A fractured sandstone aquifer at an industrial site in southern California is contaminated with trichloroethene (TCE) and cis-1,2-dichloroethene (cis-DCE) to depths in excess of 244 m. Field monitoring data suggest that TCE is undergoing reduction to cis-DCE and that additional attenuation is occurring. However, vinyl chloride (VC) and ethene have not been detected in significant amounts, so that if transformation is occurring, a process other than reductive dechlorination must be responsible. The objective of this study was to evaluate the occurrence of biotic and abiotic transformation processes at this site for TCE, cis-DCE, and VC. Anaerobic microcosms were constructed with site groundwater and sandstone core samples. 14C-labeled compounds were used to detect transformation products (e.g., CO2 and soluble products) that are not readily identifiable by headspace analysis. The microcosms confirmed the occurrence of biotic reduction of TCE to cis-DCE, driven by electron donor in the groundwater and/or sandstone. VC and ethene were not detected. Following incubation periods up to 22 months, the distribution of 14C indicated statistically significant transformation of [14C]TCE and [14C]cis-DCE in live microcosms, to as high as 10% 14CO2 from TCE and 20% 14CO2 from cis-DCE. In autoclaved microcosms, significant transformation of [14C]TCE and [14C]cis-DCE also occurred; although some 14CO2 accumulated, the predominant 14C product was soluble and could not be stripped by N2 from an acidic solution (referred to as nonstrippable residue, or NSR). Characterization of the NSR by high-performance liquid and ion chromatography identified glycolate, acetate, and formate as significant components. These results suggest that a combination of abiotic and biotic transformation processes is responsible for attenuation of TCE and cis-DCE in the fractured sandstone aquifer. Tracking the distribution of 14C during the microcosm study was essential for observing these phenomena.

  2. Sandstone copper assessment of the Teniz Basin, Kazakhstan: Chapter R in Global mineral resource assessment

    Science.gov (United States)

    Cossette, Pamela M.; Bookstrom, Arthur A.; Hayes, Timothy S.; Robinson,, Gilpin R.; Wallis, John C.; Zientek, Michael L.

    2014-01-01

    The U.S. Geological Survey (USGS) conducts national and global resource assessments (mineral, energy, water, and biological) to provide data and scientific analyses to support decision making. Three-part mineral resource assessments result in informed, unbiased, quantitative, and probabilistic estimates of undiscovered mineral resources and deposits. In particular, mineral assessment results inform decisions concerning land-use and mineral-resource development. A probabilistic mineral resource assessment of the sandstone subtype of sediment-hosted stratabound copper deposits in the Teniz Basin, Kazakhstan, was undertaken by the USGS.

  3. Relationships between stylolites and cementation in sandstone reservoirs: Examples from the North Sea, U.K. and East Greenland

    Science.gov (United States)

    Baron, Martin; Parnell, John

    2007-01-01

    The reservoir potential of hydrocarbon sandstone reservoirs may be significantly reduced by compartmentation as a result of the development of stylolites. A petrographic and fluid inclusion microthermometric study was performed on sandstones containing abundant stylolites from the Buchan, Galley and Scott Fields in the Outer Moray Firth, offshore Scotland, and from a palaeo-oil bearing sequence in East Greenland. The main objective of this study was to further constrain the temperatures and burial depths at which stylolitization occurs in sandstone reservoirs. The sandstones containing abundant stylolites are also characterized by their highly cemented nature. Numerous occurrences of quartz overgrowths clearly truncated by sutured stylolites are evident in all of the samples. Fluid inclusion microthermometry reveals that quartz cementation, which is interpreted to be coeval with stylolitization, occurred at minimum temperatures of between 86 and 136 °C. Basin modelling of the Scott and Galley Fields indicates that quartz cementation and stylolite development formed at depths greater than 2.5 km which were attained during rapid Tertiary burial. The occurrence of hydrocarbon fluid inclusions within healed microfractures orientated at high angles to the stylolites suggests that these microfractures provided pathways for hydrocarbon migration in the highly cemented, low permeability zones associated with highly stylolitized sandstones.

  4. Impact of depositional facies on the distribution of diagenetic alterations in the Devonian shoreface sandstone reservoirs, Southern Ghadamis Basin, Libya

    Science.gov (United States)

    Khalifa, Muftah Ahmid; Morad, Sadoon

    2015-11-01

    The middle Devonian, shoreface quartz arenites (present-day burial depths 2833-2786 m) are important oil and gas reservoirs in the Ghadamis Basin, western Libya. This integrated petrographic and geochemical study aims to unravel the impact of depositional facies on distribution of diagenetic alterations and, consequently, related reservoir quality and heterogeneity of the sandstones. Eogenetic alterations include the formation of kaolinite, pseudomatrix, and pyrite. The mesogenetic alterations include cementation by quartz overgrowths, Fe-dolomite/ankerite, and illite, transformation of kaolinite to dickite, illitization of smectite, intergranular quartz dissolution, and stylolitization, and albitization of feldspar. The higher energy of deposition of the coarser-grained upper shoreface sandstones combined with less extensive chemical compaction and smaller amounts of quartz overgrowths account for their better primary reservoir quality compared to the finer-grained, middle-lower shoreface sandstones. The formation of kaolin in the upper and middle shoreface sandstones is attributed to a greater flux of meteoric water. More abundant quartz overgrowths in the middle and lower shoreface is attributed to a greater extent of stylolitization, which was promoted by more abundant illitic clays. This study demonstrated that linking the distribution of diagenetic alterations to depositional facies of shoreface sandstones leads to a better understanding of the impact of these alterations on the spatial and temporal variation in quality and heterogeneity of the reservoirs.

  5. Strength Anisotropy of Berea Sandstone: Results of X-Ray Computed Tomography, Compression Tests, and Discrete Modeling

    Science.gov (United States)

    Kim, Kwang Yeom; Zhuang, Li; Yang, Hwayoung; Kim, Hanna; Min, Ki-Bok

    2016-04-01

    Berea sandstone in northern Ohio is a transversely isotropic rock. X-ray CT investigations showed that its internal structure is composed of cross-bedded loose layers and relatively thin tightly packed layers called bedding. Uniaxial compression tests were performed on different Berea sandstone specimens. The uniaxial compressive strength (UCS) decreases with increasing porosity, and also decreases with increasing inclination of the bedding plane relative to horizontal line. Two-dimensional discrete modeling was applied to investigate the micromechanical behavior of Berea sandstone. Different microparameters were assigned to loose and tight layers. The UCS simulation results agree well with the experimental results. At the peak stress, cracks almost always develop in loose layers regardless of the bedding plane orientation. In addition, both normal and shear cracks occur earlier for specimens with a higher inclination angle. No correlations were found between the inclination angle of failure planes and the orientation of bedding planes. The bedding planes of Berea sandstone are not weak planes. The strength anisotropy of Berea sandstone is not significant compared with other rocks such as shale, gneiss, and schist.

  6. Microbial community analysis of fresh and old microbial biofilms on Bayon temple sandstone of Angkor Thom, Cambodia.

    Science.gov (United States)

    Lan, Wensheng; Li, Hui; Wang, Wei-Dong; Katayama, Yoko; Gu, Ji-Dong

    2010-07-01

    The temples of Angkor monuments including Angkor Thom and Bayon in Cambodia and surrounding countries were exclusively constructed using sandstone. They are severely threatened by biodeterioration caused by active growth of different microorganisms on the sandstone surfaces, but knowledge on the microbial community and composition of the biofilms on the sandstone is not available from this region. This study investigated the microbial community diversity by examining the fresh and old biofilms of the biodeteriorated bas-relief wall surfaces of the Bayon Temple by analysis of 16S and 18S rRNA gene sequences. The results showed that the retrieved sequences were clustered in 11 bacterial, 11 eukaryotic and two archaeal divisions with disparate communities (Acidobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Proteobacteria; Alveolata, Fungi, Metazoa, Viridiplantae; Crenarchaeote, and Euyarchaeota). A comparison of the microbial communities between the fresh and old biofilms revealed that the bacterial community of old biofilm was very similar to the newly formed fresh biofilm in terms of bacterial composition, but the eukaryotic communities were distinctly different between these two. This information has important implications for understanding the formation process and development of the microbial diversity on the sandstone surfaces, and furthermore to the relationship between the extent of biodeterioration and succession of microbial communities on sandstone in tropic region.

  7. Members of the LHC Resources Review Boards

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Photo 01: Members of the LHCRRB visiting Point 2, hosting the ALICE experiment From l. to r. : W. Korda, Head of the VIP Office; P. Rimmer, CERN public relations, J. Seed, Member of the LHCRRB, J.-P. Revol, ALICE CERN Team Leader; J. Bartke, Member of the LHCRRB; F. Suransky, Member of the LHCRRB; J. Schukraft, Spokesperson, ALICE experiment and S. Molinari, VIP Office. Photo 02: Members of the LHC Resources Review Boards visiting the ALICE magnet at Point 2. L. to. r.: O. Dines-Hansen, H. Boggild, S. Irgens-Jensens, H.A. Gustafsson Photo 03: Members of the LHCRRB visiting Point 2, hosting the ALICE experiment From l. t to r.: J.Richter, Member of the LHCRRB; H. Gutbrod, Deputy Spokesperson, ALICE experiment; G. Paic, ALICE experiment; D. Muller, Member of the LHCRRB; P. Brau-Munzinger, ALICE experiment; R. Santo, Member of the LHCRRB, A. Van Rijn, Member of the LHCRRB; J. Engelen, Member of the LHCRRB.

  8. Member end releases in framed structures

    Science.gov (United States)

    Stallings, J. M.

    1993-02-01

    Discontinuities such as internal hinges are commonly encountered in framed structures. A general method of including discontinuities in stiffness method analyses of planar frames by the release of member end forces is developed. Modifications are made to the member stiffness matrix and equivalent joint load vector to account for the released end forces. A FORTRAN algorithm is given that makes the necessary modifications to the member stiffness matrix and equivalent joint load vector for the standard planar frame member. The algorithm allows combinations of up to three member end forces to be released (specified at zero or nonzero values). An algorithm is also given that calculates the unknown member end displacements at the released member end forces. Numerical examples are given to illustrate the uses and capabilities of the algorithms.

  9. Investigating the Effect of Positive Discipline on the Learning Process and its Achieving Strategies with Focusing on the Students' Abilities

    OpenAIRE

    Ghorbani Somayeh; Jaafari SayyedMirshah; Sharif SayyedMostafa; Arbabisarjou Azizollah

    2013-01-01

    The aim of this study is to investigate the effect of positive discipline on the learning process and its achieving strategies from teachers and principals’ point of view in the city of Ahwaz in 2011-2012 academic years. The method of research was descriptive-survey. The statistical population of this study includes all Ahwaz high school teachers and principals. All of the sample members (105 principals and 321 teachers) were selected by stratified random sampling. In order to collect the dat...

  10. 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

    Institute of Scientific and Technical Information of China (English)

    LUO; JingLan; LI; Jian; YANG; BingHu

    2007-01-01

    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

  11. 7 CFR 989.29 - Initial members and nomination of successor members.

    Science.gov (United States)

    2010-01-01

    ... Committee § 989.29 Initial members and nomination of successor members. (a) Initial members. Members and... in nomination shall be given the opportunity to provide the committee a short statement outlining... during the preceding crop year on the Committee. Nominations shall be made by and from handlers,...

  12. Discussion on origin of clay minerals in outcropped sandstone from Lower Cretaceous Chengzihe Formation and Muling Formation in Jixi Basin

    Institute of Scientific and Technical Information of China (English)

    LIU Jianying; LIU Li; QU Xiyu

    2009-01-01

    Clay minerals in the outcropped sandstone from Lower Cretaceous Chengzihe Formation and Muling Formation in Jixi Basin were analyzed by X-ray diffraction. The results show that the clay minerals mainly consist of illite, kaollinite and illite/smectite, which can be divided into two types: kaolinite- and illite/smectite types. The outcropped sandstone occurred in middle diagenetic stage-A on the basis of the clay mineral composition. The development factor of the formation of kaolinite type clay mineral is caused mainly by the organic acid from the coal-bearing formation and mudstone during the diagenesis process in Lower Cretaceous Chengzihe Formation and Muling Formation in the Jixi Basin. The weak hydrodynamic force of sedimentary facies made the sandstone leaching condition poor, which is the reason forming the aggregation of clay minerals of the illite/smectite-and illite types.

  13. Provenance study from petrography of the late Permian - Early Triassic sandstones of the Balfour Formation Karoo Supergroup, South Africa

    Science.gov (United States)

    Oghenekome, M. E.; Chatterjee, T. K.; Hammond, N. Q.; van Bever Donker, J. M.

    2016-02-01

    Non marine clastic sediments from the Late Permian - Early Triassic Balfour Formation of the Karoo Supergroup were studied to infer the composition, provenance and influence of weathering conditions. Petrographic studies based on quantitative analysis of the detrital minerals reveal that these sediments (mainly sandstones) are mostly composed of quartz, feldspar and sedimentary and metamorphic rock fragments. There is no significant petrographic variation across the sandstone succession of the study. The sandstones are dominantly feldspathic litharenite and ultralithofeldspathic in composition indicating a metamorphic source area. Modal analysis data plot in the dissected and transitional arc block provenance fields of QmFLt (quartz-feldspar-lithic fragments) diagram suggesting an active margin and magmatic arc signature preserving a recycled provenance.

  14. Provenance of upper Triassic sandstone, southwest Iberia (Alentejo and Algarve basins): tracing variability in the sources

    Science.gov (United States)

    Pereira, M. F.; Ribeiro, C.; Gama, C.; Drost, K.; Chichorro, M.; Vilallonga, F.; Hofmann, M.; Linnemann, U.

    2016-01-01

    Laser ablation ICP-MS U-Pb analyses have been conducted on detrital zircon of Upper Triassic sandstone from the Alentejo and Algarve basins in southwest Iberia. The predominance of Neoproterozoic, Devonian, Paleoproterozoic and Carboniferous detrital zircon ages confirms previous studies that indicate the locus of the sediment source of the late Triassic Alentejo Basin in the pre-Mesozoic basement of the South Portuguese and Ossa-Morena zones. Suitable sources for the Upper Triassic Algarve sandstone are the Upper Devonian-Lower Carboniferous of the South Portuguese Zone (Phyllite-Quartzite and Tercenas formations) and the Meguma Terrane (present-day in Nova Scotia). Spatial variations of the sediment sources of both Upper Triassic basins suggest a more complex history of drainage than previously documented involving other source rocks located outside present-day Iberia. The two Triassic basins were isolated from each other with the detrital transport being controlled by two independent drainage systems. This study is important for the reconstruction of the late Triassic paleogeography in a place where, later, the opening of the Central Atlantic Ocean took place separating Europe from North America.

  15. Linear and nonlinear modulus surfaces in stress space, from stress-strain measurements on Berea sandstone

    Directory of Open Access Journals (Sweden)

    M. Boudjema

    2003-01-01

    Full Text Available The elastic response of many rocks to quasistatic stress changes is highly nonlinear and hysteretic, displaying discrete memory. Rocks also display unusual nonlinear response to dynamic stress changes. A model to describe the elastic behavior of rocks and other consolidated materials is called the Preisach-Mayergoyz (PM space model. In contrast to the traditional analytic approach to stress-strain, the PM space picture establishes a relationship between the quasistatic data and a number density of hysteretic mesoscopic elastic elements in the rock. The number density allows us to make quantitative predictions of dynamic elastic properties. Using the PM space model, we analyze a complex suite of quasistatic stress-strain data taken on Berea sandstone. We predict a dynamic bulk modulus and a dynamic shear modulus surface as a function of mean stress and shear stress. Our predictions for the dynamic moduli compare favorably to moduli derived from time of flight measurements. We derive a set of nonlinear elastic constants and a set of constants that describe the hysteretic behavior of the sandstone.

  16. Imaging pore space in tight gas sandstone reservoir: insights from broad ion beam cross-sectioning

    Directory of Open Access Journals (Sweden)

    Konstanty J.

    2010-06-01

    Full Text Available Monetization of tight gas reservoirs, which contain significant gas reserves world-wide, represents a challenge for the entire oil and gas industry. The development of new technologies to enhance tight gas reservoir productivity is strongly dependent on an improved understanding of the rock properties and especially the pore framework. Numerous methods are now available to characterize sandstone cores. However, the pore space characterization at pore scale remains difficult due to the fine pore size and delicate sample preparation, and has thus been mostly indirectly inferred until now. Here we propose a new method of ultra high-resolution petrography combining high resolution SEM and argon ion beam cross sectioning (BIB, Broad Ion Beam which prepares smooth and damage free surfaces. We demonstrate this method using the example of Permian (Rotliegend age tight gas sandstone core samples. The combination of Ar-beam cross-sectioning facility and high-resolution SEM imaging has the potential to result in a step change in the understanding of pore geometries, in terms of its morphology, spatial distribution and evolution based on the generation of unprecedented image quality and resolution enhancing the predictive reliability of image analysis.

  17. Evaluation and prevention of formation damage in offshore sandstone reservoirs in China

    Institute of Scientific and Technical Information of China (English)

    Yang Shenglai; Sheng Zhichao; Liu Wenhui; Song Zhixue; Wu Ming; Zhang Jianwei

    2008-01-01

    Reduction in water injectivity would be harmful to the waterflood development of offshore sandstone oil reservoirs. In this paper the magnitude of formation damage during water injection was evaluated by analyzing the performance of water injection in the Bohai offshore oilfield, China. Two parameters, permeability reduction and rate of wellhead pressure rise, were proposed to evaluate the formation damage around injection wells. The pressure performance curve could be divided into three stages with different characteristics. Analysis of field data shows that formation damage caused by water injection was severe in some wells in the Bohai offshore oilfield, China. In the laboratory, the content of clay minerals in reservoir rock was analyzed and sensitivity tests (including sensitivity to water,flow rate, alkali, salt and acid) were also conducted. Experimental results show that the reservoir had a strong to medium sensitivity to water (i.e. clay swelling) and a strong to medium sensitivity to flow rate,which may cause formation damage. For formation damage prevention, three injection schemes of clay stabilizer (CS) were studied, i.e. continuous injection of low concentration CS (Ci), slug injection of high concentration CS (SI), and slug injection of high concentration CS followed by continuous injection of low concentration CS (SI-CI). Core flooding experiments show that SI-CI is an effective scheme to prevent formation damage and is recommended for the sandstone oil reservoirs in the Bohai offshore oilfield during water injection.

  18. Fragmentation characteristics analysis of sandstone fragments based on impact rockburst test

    Institute of Scientific and Technical Information of China (English)

    Dongqiao Liu; Dejian Li; Fei Zhao; Chengchao Wang

    2014-01-01

    Impact rockburst test on sandstone samples with a central hole is carried out under true triaxial static loads and vertical dynamic load conditions, and rock fragments after the test are collected. The fragments of sandstone generated from strain rockburst test and uniaxial compression test are also collected. The fragments are weighed and the length, width and thickness of each piece of fragments are measured respectively. The fragment quantities with coarse, medium, fine and micro grains in different size ranges, mass and particles distributions are also analyzed. Then, the fractal dimension of fragments is calculated by the methods of size-frequency, mass-frequency and length-to-thickness ratio-frequency. It is found that the crushing degree of impact rockburst fragments is higher, accompanied with blocky character-istics observably. The mass percentage of small grains, including fine and micro grains, in impact rock-burst test is higher than those in strain rockburst test and uniaxial compression test. Energy dissipation from rockburst tests is more than that from uniaxial compression test, as the quantity of micro grains generated does.

  19. Predicting the permeability of sandstone from image analysis of pore structure

    Science.gov (United States)

    Lock, Peter A.; Jing, Xudong; Zimmerman, Robert W.; Schlueter, Erika M.

    2002-11-01

    A model is developed that allows accurate prediction of the permeability of a core sample of sedimentary rock, based on two-dimensional image analysis of its pore structure. The pore structure is idealized as consisting of a cubic network of pore tubes, with the tubes having an arbitrary distribution of cross-sectional areas and shapes. The areas and perimeters of the individual pores are estimated from image analysis of scanning electron micrographs of thin sections, with appropriate stereological corrections introduced to account for the angle between axis of the pore tube and plane of the thin section. The individual conductances of each tube are estimated from the measured areas and perimeters, using the hydraulic radius approximation. Variations in the pore diameter along the length of the tube are accounted for with a "constriction factor" whose derivation is based on laminar flow through an irregular tube. Effective-medium theory is used to find the effective single-tube conductance, based on the measured distribution of individual conductances. This procedure is applied to several consolidated North Sea reservoir sandstones, and some outcrop sandstones, with permeabilities ranging from 20 to 1400 mD. The predicted permeabilities are typically within a factor of 2 of the measured values, with an average error in logk of only 0.168.

  20. Experimental investigation on the energy evolution of dry and water-saturated red sandstones

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhizhen; Gao Feng

    2015-01-01

    In order to investigate the effect of water content on the energy evolution of red sandstone, the axial loading–unloading experiments on dry and water-saturated sandstone samples were conducted, and the distribution and evolution of elastic energy and dissipated energy within the rock were measured. The results show that the saturation process from dry to fully-saturated states reduces the strength, rigid-ity and brittleness of the rock by 30.2%, 25.5%and 16.7%, respectively. The water-saturated sample has larger irreversible deformation in the pre-peak stage and smaller stress drop in the post-peak stage. The saturation process decreases the accumulation energy limit by 38.9%, but increases the dissipated energy and residual elastic energy density, thus greatly reducing the magnitude and rate of energy release. The water-saturated sample has lower conversion efficiency to elastic energy by 3%in the pre-peak region; moreover, the elastic energy ratio falls with a smaller range in the post-peak stage. Therefore, saturation process can greatly reduce the risk of dynamic disaster, and heterogeneous water content can lead to dynamic disaster possibly on the other hand.

  1. Geochemical discriminations of sandstones from the Mohe Foreland basin, northeastern China: Tectonic setting and provenance

    Institute of Scientific and Technical Information of China (English)

    HE Zhengjun; LI Jinyi; MO Shenguo; Andrey A. Sorokin

    2005-01-01

    Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tectonic settings in the period of basin deposition. Results of geochemical analyses in this paper show that sandstone samples of the Mesozoic Mohe basin fall in active continental margin settings on several kinds of tectonic discriminatory diagrams (Bhatia et al. 1983, 1986; Roser et al. 1986,1988,1999). The samples are also characterized by binary-system provenances, whose terrigenous clastic materials mainly derived from the orogenic belt near the basin to the north and secondarily from the continental region in the south of the basin at the same time. The research results of rock geochemistry, combined with tectonic analysis, reflect that tectonic type of the basin is a foreland basin with nature of depositional accumulation of molass, but not continental rift basin considered in the past. This finding provides important evidence of rock geochemistry for the original structural linkage between the Mohe Foreland Basin and Mongol-Okhotsk Orogen in Mesozoic.

  2. Reservoir heterogeneity in Carboniferous sandstone of the Black Warrior basin. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, R.L.; Pashin, J.C.; Carroll, R.E.; Irvin, G.D.; Moore, H.E.

    1994-04-01

    Although oil production in the Black Warrior basin of Alabama is declining, additional oil may be produced through improved recovery strategies, such as waterflooding, chemical injection, strategic well placement, and infill drilling. High-quality characterization of reservoirs in the Black Warrior basin is necessary to utilize advanced technology to recover additional oil and to avoid premature abandonment of fields. This report documents controls on the distribution and producibility of oil from heterogeneous Carboniferous reservoirs in the Black Warrior basin of Alabama. The first part of the report summarizes the structural and depositional evolution of the Black Warrior basin and establishes the geochemical characteristics of hydrocarbon source rocks and oil in the basin. This second part characterizes facies heterogeneity and petrologic and petrophysical properties of Carter and Millerella sandstone reservoirs. This is followed by a summary of oil production in the Black Warrior basin and an evaluation of seven improved-recovery projects in Alabama. In the final part, controls on the producibility of oil from sandstone reservoirs are discussed in terms of a scale-dependent heterogeneity classification.

  3. Reservoir heterogeneity in carboniferous sandstone of the Black Warrior basin. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, R.L.; Pashin, J.C.; Carroll, R.E.; Irvin, G.D.; Moore, H.E.

    1994-06-01

    Although oil production in the Black Warrior basin of Alabama is declining, additional oil may be produced through improved recovery strategies, such as waterflooding, chemical injection, strategic well placement, and infill drilling. High-quality characterization of reservoirs in the Black Warrior basin is necessary to utilize advanced technology to recover additional oil and to avoid premature abandonment of fields. This report documents controls on the distribution and producibility of oil from heterogeneous Carboniferous reservoirs in the Black Warrior basin of Alabama. The first part of the report summarizes the structural and depositional evolution of the Black Warrior basin and establishes the geochemical characteristics of hydrocarbon source rocks and oil in the basin. This second part characterizes facies heterogeneity and petrologic and petrophysical properties of Carter and Millerella sandstone reservoirs. This is followed by a summary of oil production in the Black Warrior basin and an evaluation of seven improved-recovery projects in Alabama. In the final part, controls on the producibility of oil from sandstone reservoirs are discussed in terms of a scale-dependent heterogeneity classification.

  4. Characteristics of Chang 21 Low Permeability Sandstone Reservoir in Shunning Oil Field

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-min; YU Liu-ying

    2006-01-01

    Characteristics of Chang 21 low permeability sandstone reservoir of Shunning oil field are analyzed and evaluated based on the data of well logging and experiment. The result shows that 1) the Chang 21 low permeability reservoir belongs to the classification of middle-to-fine sized feldspar sandstone, with its components being low in maturity, deposited in distributary rivers in the front of the delta; 2) the reservoir is obviously dominated by a low or a very low permeability with a linear variation tendency different from that of the ultra-low permeability reservoir; 3) the spatial variation in lithology and physical properties of the reservoir are controlled by the sedimentary facies zones, and 4)the physical property of the reservoir is significantly influenced by clastic constituents and their structure, and the constituent of cement materials and their content. The result also shows that the diagenesis action of the reservoir is quite strong in which dissolution greatly modified the reservoir In addition, the inter-granular dissolved pores are the mainly developed ones and the micro-structure is dominated by the combination of middle-to-large sized pores with fine-to-coarse throats. Finally, the radius of the throats is in good exponential correlation with permeability and the seepage capacity comes from those large sized throats.

  5. Impact of interfacial tension on residual CO2 clusters in porous sandstone

    Science.gov (United States)

    Jiang, Fei; Tsuji, Takeshi

    2015-03-01

    We develop a numerical simulation that uses the lattice Boltzmann method to directly calculate the characteristics of residual nonwetting-phase clusters to quantify capillary trapping mechanisms in real sandstone. For this purpose, a digital-rock-pore model reconstructed from micro-CT-scanned images of Berea sandstone is filtered and segmented into a binary file. The residual-cluster distribution is generated following simulation of the drainage and imbibition processes. The characteristics of the residual cluster in terms of size distribution, major length, interfacial area, and sphericity are investigated under conditions of different interfacial tension (IFT). Our results indicate that high interfacial tension increases the residual saturation and leads to a large size distribution of residual clusters. However, low interfacial tension results in a larger interfacial area, which is beneficial for dissolution and reaction processes during geological carbon storage. Analysis of the force balance acting on the residual clusters demonstrates that trapping stability is higher in high interfacial tension case, and the interfacial tension should be a controlling factor for the trapping stability in addition to the pore geometry and connectivity. The proposed numerical method can handle the complex displacement of multicomponent systems in porous media. By using this method, we can obtain residual-cluster distributions under different conditions for optimizing the storage capacity of carbon-storage projects.

  6. Quantitative study on experimentally observed poroelastic behavior of Berea sandstone in two-phase fluid system

    Science.gov (United States)

    Goto, Hiroki; Aichi, Masaatsu; Tokunaga, Tomochika; Yamamoto, Hajime; Ogawa, Toyokazu; Aoki, Tomoyuki

    2014-08-01

    Coupled two-phase fluid flow and poroelastic deformation of Berea sandstone is studied through laboratory experiment and numerical simulation. In the experiment, compressed air was infiltrated from the bottom of a water-saturated cylindrical Berea sandstone sample under hydrostatic external stress condition. Both axial and circumferential strains at half the height of the sample showed sudden extension and monotonic and gradual extension afterward. Numerical simulation based on thermodynamically consistent constitutive equations was conducted in order to quantitatively analyze the experimental results. In a simulation assuming isotropy of material properties, the volumetric discharge rate of water at the outlet and one of the axial, circumferential, and volumetric strains at half the height of the sample were reproduced well by each parameter set, while the other two strains were not. When introducing transverse isotropy, all the experimental data were reproduced well. In addition, the effect of saturation dependency of Bishop's effective stress coefficient on the deformation behavior of porous media was discussed, and it was found that strains, both axial and circumferential, are sensitive to the coefficient.

  7. Effect of Sterilization by Dry Heat or Autoclaving on Bacterial Penetration through Berea Sandstone.

    Science.gov (United States)

    Jenneman, G E; McInerney, M J; Crocker, M E; Knapp, R M

    1986-01-01

    A study was undertaken to determine why bacteria could penetrate lengths of consolidated sandstone (Berea) faster when the sandstone was sterilized by autoclaving than when dry heat (150 degrees C, 3 h) was used. Changes in permeability, porosity, and pore entrance size of the rock as a result of autoclaving were not sufficient to explain the differences in penetration times observed, but electron dispersion spectroscopy and electron microscopy of the rock revealed changes in mineral composition and clay morphology. Autoclaved cores contained more chloride than dry-heated cores, and the clays of autoclaved cores were aggregated and irregularly shaped. Therefore, the decreases in bacterial penetration rates caused by autoclave sterilization were probably the result of a change in surface charge of the pores of the rock and of a reduction in surface area of clays available for adhesion. The results implied that dry-heat sterilization was preferable to autoclaving when examining biotic and abiotic interactions in a native-state rock model.

  8. Pore structure and limit pressure of gas slippage effect in tight sandstone.

    Science.gov (United States)

    You, Lijun; Xue, Kunlin; Kang, Yili; Liao, Yi; Kong, Lie

    2013-01-01

    Gas slip effect is an important mechanism that the gas flow is different from liquid flow in porous media. It is generally considered that the lower the permeability in porous media is, the more severe slip effect of gas flow will be. We design and then carry out experiments with the increase of backpressure at the outlet of the core samples based on the definition of gas slip effect and in view of different levels of permeability of tight sandstone reservoir. This study inspects a limit pressure of the gas slip effect in tight sandstones and analyzes the characteristic parameter of capillary pressure curves. The experimental results indicate that gas slip effect can be eliminated when the backpressure reaches a limit pressure. When the backpressure exceeds the limit pressure, the measured gas permeability is a relatively stable value whose range is less than 3% for a given core sample. It is also found that the limit pressure increases with the decreasing in permeability and has close relation with pore structure of the core samples. The results have an important influence on correlation study on gas flow in porous medium, and are beneficial to reduce the workload of laboratory experiment.

  9. Behaviour of layered sandstone under Brazilian test conditions:Layer orientation and shape effects

    Institute of Scientific and Technical Information of China (English)

    Abbass Tavallali; André Vervoort

    2013-01-01

    The experimental study in this paper focuses on the effects of the layer orientation and sample shape on failure strength and fracture pattern of samples tested under Brazilian test conditions (i.e. diametrical loading of cylindrical discs) for one particular layered sandstone which is from Modave in the south of Belgium. The variations of the strength in combination with the failure patterns are examined as a function of the inclination angle between the layer plane and the loading direction. The experimental, results clearly show that the induced fracture patterns are a combination of tensile and/or shear fractures. In shape effect experiments the layer thickness and the number of layer boundaries are investigated. Different blocks of Modave sandstone are used to prepare samples. The layer thickness is different among the various blocks, but the layer thickness in each studied rock block can be considered to be constant;hence, the number of layer boundaries changes according to the sample diameter for samples of the same block. The experimental study shows that the layer thickness plays a more important role than the number of layer boundaries per sample.

  10. Impact of sauropod dinosaurs on lagoonal substrates in the Broome Sandstone (Lower Cretaceous), Western Australia.

    Science.gov (United States)

    Thulborn, Tony

    2012-01-01

    Existing knowledge of the tracks left by sauropod dinosaurs (loosely 'brontosaurs') is essentially two-dimensional, derived mainly from footprints exposed on bedding planes, but examples in the Broome Sandstone (Early Cretaceous) of Western Australia provide a complementary three-dimensional picture showing the extent to which walking sauropods could deform the ground beneath their feet. The patterns of deformation created by sauropods traversing thinly-stratified lagoonal deposits of the Broome Sandstone are unprecedented in their extent and structural complexity. The stacks of transmitted reliefs (underprints or ghost prints) beneath individual footfalls are nested into a hierarchy of deeper and more inclusive basins and troughs which eventually attain the size of minor tectonic features. Ultimately the sauropod track-makers deformed the substrate to such an extent that they remodelled the topography of the landscape they inhabited. Such patterns of substrate deformation are revealed by investigating fragmentary and eroded footprints, not by the conventional search for pristine footprints on intact bedding planes. For that reason it is not known whether similar patterns of substrate deformation might occur at sauropod track-sites elsewhere in the world.

  11. Genesis Types and Diagenesis Compaction Mechanisms of Sandstone Rreservoirs in Dynamic Environments in Oil/Gas Basins in China

    Institute of Scientific and Technical Information of China (English)

    Shou Jianfeng; Si Chunsong; Wang Xin

    2006-01-01

    The diversity of sandstone diagenesis mechanisms caused by the complex geological conditions of oil/gas basins in China could hardly be reasonably explained by the traditional concept of burial diagenesis. Three genesis types of thermal diagenesis, tectonic diagenesis and fluid diagenesis are presented on the basis of the dynamic environment of the oil/gas basins and the controlling factors and mechanisms of sandstone diagenesis. Thermal diagenesis of sandstone reservoirs is related not only to the effect of formation temperature on diagenesis, but also to the significant changes in diagenesis caused by geothermal gradients. The concept of thermal compaction is presented. Thermal compaction becomes weaker with increasing depth and becomes stronger at a higher geothermal gradient. At the same formation temperature, the sandstone porosity in the region with a lower geothermal gradient is e0.077+0.0042T times higher than that in the region with a higher geothermal gradient. Both sudden and gradual changes are observed in diagenetic evolution caused by structural deformation. Average sandstone compaction increased by 0.1051% for every 1.0MPa increase of lateral tectonic compressional stress, while late tectonic napping helped to preserve a higher porosity of underlying sandstone reservoir. Fluid diagenesis is a general phenomenon. The compaction caused by fluid properties is significant. The coarser the grain size, the stronger the fluid effect on compaction. The greater the burial depth, the weaker the fluid effect on compaction for the specific reservoir lithology and the greater the difference in the fluid effects on compaction between different grain sizes.

  12. Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan, Northwest China: Evidence from sandstone detrital and geochemical records

    Institute of Scientific and Technical Information of China (English)

    LI; Zhong; GUO; Hong; WANG; Daoxuan

    2005-01-01

    Similar to compositional evolution of sandstone modes and detrital heavy minerals from different profiles in the Kuqa Depression, Northwest China, major element analysis of whole sandstones from the same profiles shows four discontinuous depositional interfaces or periods, respectively corresponding to Lower Triassic\\Middle Triassic, Upper Jurassic\\Lower Cretaceous, Lower Cretaceous\\Paleogene and Miocene\\Pliocene, and indicates five-phase evolution during Mesozoic-Cenozoic: (1) From the first to fifth phase, a depositional suite changes from maroon and coarse clastic, through grey-dark grey and fine, red and coarse, red-mottled, interlayered by gypsum, to brown and coarse clastic assemblages, accompanying detrital component evolution in unstable-stable-unstable-very unstable-very unstable assemblages. It is indicated that carbonate and complex detritus gradually dominate in sandstones in post-Late Jurassic, with rapid reduction of compositional maturity. (2) For major element geochemical parameters of whole sandstones, CaO and +MgO contents show a change sequence in high-low-high-higher-highest values, with rapid increasing in post-Late Jurassic. (3) Contra some aggregative indicators for weathering indexes of sandstone detrital component, Al2O3/(CaO+Na2O) and ln(Q/(L+CE)), show a change sequence in low-high-low-lower-lowest ratios, with rapid decreasing in post-Late Jurassic. It is found that sandstone samples of the first, second and later three phases may be distinguished from the A-CN-K and A-CNK-FM diagrams respectively. Therefore, in the Kuqa Depression-Tianshan, the most important discontinuous depositional interface recording paleotectonic and paleoclimatic transition occurred in Early Triassic\\Middle Triassic and Late Jurassic\\Early Cretaceous, respectively, and, however, tectonic differentiations of basin-range system finally result in distinct depositional systems but similar detrital weathering indexes across the Lower Cretaceous\\Paleogene and

  13. A Effect discussion of transient electromagnetic sounding technique in paleochannel-type sandstone-hosted uranium deposit

    International Nuclear Information System (INIS)

    On the base of the application of transient electromagnetic technique of paleochannel-type sandstone-hosted uranium deposits in Tengchong region of Yunan Province, this paper analyses the detect example. It discusses the theory foundation of TEM, fieldwork means, data processing and interpret. By contrast with routine electricity farad, the transient electromagnetic technique have the special merit and favorable space resolve gender under conditions of intricacy terrain. This means can get good effect in detecting paleochannel-type sandstone-hosted uranium deposits space position. It is a good reference for other prospecting and exploration work

  14. Geophysical and geochemical prospecting techniques for the exploration of the sandstone type uranium deposits in interlayer oxidation zone

    International Nuclear Information System (INIS)

    Sandstone type uranium deposits in interlayer oxidation zone usually are large or super large and in-situ leachable. Geophysical and geochemical techniques are effective in determining the distribution of sandstone body and interlayer oxidation zone, and locating uranium orebody and investigating subsurface uranium metallogenetic geological environment. Starting with the principle of exploration methods and some application examples, this paper discusses the key techniques applied at each prospecting stage, and emphasizes that, comprehensive geophysical and geochemical methods mush be used in combination with geological information and physico-chemical properties of rocks (minerals) in the working area for carrying out the reconnaissance, prospecting and exploration of uranium deposits

  15. Biodegradation of phenols in a sandstone aquifer under aerobic conditions and mixed nitrate and iron reducing conditions

    DEFF Research Database (Denmark)

    Broholm, Mette; Arvin, Erik

    2000-01-01

    in the groundwater. The potential for biodegradation of the phenols in the sandstone aquifer at the site has been investigated in laboratory microcosms under aerobic (oxygen amended) and mixed nitrate and iron reducing (nitrate enriched and unamended) anaerobic conditions, at a range of concentrations (low: similar...... to 5 mg 1(-1): high: similar to 60 mg 1(-1), and very high: similar to 600 mg 1(-1)) and in the presence of other organic coal-tar compounds (mono- and polyaromatic hydrocarbons (BTEXs and PAHs) and heterocyclic compounds (NSOs)) and ammonia liquor. Sandstone cores and groundwater for the microcosms...

  16. Estimating the evolution of atrazine concentration in a fractured sandstone aquifer using lumped-parameter models and taking land-use into account

    Science.gov (United States)

    Farlin, J.; Gallé, T.; Bayerle, M.; Pittois, D.; Braun, C.; El Khabbaz, H.; Maloszewski, P.; Elsner, M.

    2012-04-01

    The European water framework directive and the groundwater directive require member states to identify water bodies at risk and assess the significance of increasing trend in pollutant concentration. For groundwater bodies, estimating the time to trend reversal or the pollution potential of the different sources present in the catchment require a sound understanding of the hydraulic behaviour of the aquifer. Although numerical groundwater models can theoretically be used for such forecasts, their calibration remains in many real-world cases problematic. A more parsimonious lumped-parameter model was applied to predict the evolution of atrazine concentration in springs draining a fractured sandstone aquifer in Luxembourg. Despite a nationwide ban in 2005, spring water concentrations of both atrazine and its metabolite desethylatrazine still had not begun to decrease four years later. The transfer function of the model was calibrated using tritium measurements and modified to take into account the fact that whereas tritium is applied uniformly over the entire catchment, atrazine was only used in areas where cereals are grown. We could also show that sorption processes in the aquifer can be neglected and that including pesticide degradation does not modify the shape of the atrazine breakthrough, but only affects the magnitude of the predicted spring water concentration. Results indicate that due to the large hydraulic inertia of the aquifer, trend reversal should not be expected before 2018.

  17. Early cretaceous Obernirchen and Bentheim sandstones from Germany used as dimension stone in the Netherlands: geology physical properties, architectural use and comparative weathering

    NARCIS (Netherlands)

    Dubelaar, C.W.; Nijland, T.G.

    2015-01-01

    The Netherlands, with only scarce occurrences of outcropping or shallow buried natural stone, has over centuries imported huge quantities of Early Cretaceous Bentheim Sandstone and Obernkirchen Sandstone from Germany. The present paper provides an overview of their distribution and properties releva

  18. Amphibian and Paleoisciforms from the Lower Part of the Taquaral Member of the Permian Irati Formation, São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Artur Chahud

    2010-03-01

    Full Text Available In the east-central region of the State of São Paulo, Brazil, good exposures of Permo-Carboniferous sequences of theParaná intracratonic basin are found. These sequences start with the Tubarão Supergroup deposits, the PermocarboniferousItararé Group, and the earliest Permian Guatá Group, of which the Tatuí Formation is the only unit occurring in the Stateof São Paulo. The Permian Passa Dois Group overlies the Tubarão Supergroup, with the Early Permian Irati Formation andthe Middle Permian Corumbataí Formation. Two members are recognized in the Irati Formation, Taquaral and Assistência.Most beds of the Taquaral Member are gray laminated siltic-argillaceous, but sandstone beds are present in lower outcropsof this member. One of these sandstones, 9.5 cm thick unconformably overlying sedimentos of the Tatuí Formation, exhibitsdiversifi ed vertebrate remains. The present paper deals with a Palaeonisciformes mandible fragment, one amphibianTemnospondyli tooth, and one Temnospondyli mandible fragment. These fossils are associated to Chondrichthyes andOsteichthyes. It is an open question whether the Parnaíba Basin Palaeonisciformes Brasilichthys macrognathus and theTemnospondyli Prionosuchus plummery belong to the same taxa of the Paraná Basin fossils. Only better preserved fossilsmight solve this question.

  19. Transport Properties of Carbonate and Sandstone Samples: Digital Rock Physics and Laboratory Measurements

    Science.gov (United States)

    Alabbad, A. A.; Dvorkin, J. P.

    2015-12-01

    We examined six carbonate samples that included three pairs, each pair cut from the same core, normal and parallel to the bedding. We also examined three sandstone samples comprised of a pair, cur normal and parallel to the bedding, and one sample cut normal to the bedding. For each of these samples, we obtained dual energy digital images with the resolution approximately 0.004 mm, coarser than the pore-scale resolution. As a result, we did not resolve the pore structure. Still, these images provided us with the bulk density (ρb) and photoelectric factor (Pf) at each voxel in 3D. The Pf volumes were used to estimate the mineralogy at each voxel by partitioning the carbonate mineralogy between calcite and dolomite and partitioning the sandstone mineralogy between pure quartz and "dirty sandstone" (Plumb et al., 1991) for one scenario and between pure quartz and illite for the other scenario. From this mineralogy we obtained the grain (matrix) density (ρs) at each voxel. Next, by using ρb and ρs and assuming that the pores were filled with air, we computed the total porosity (ϕt) at each voxel from mass balance. Porosity thus obtained was used to estimate the electrical formation factor (F) at each voxel by assuming that F relates to ft according to Archie's equation (Archie, 1942). We also computed the absolute permeability (k) at each voxel by assuming that k relates to ϕt according to the Kozeny-Carman equation (Carman, 1956). Next, by employing a Darcy simulator, these 3D resistivity and permeability volumes were used to compute the effective permeability and electrical formation factor of the whole samples along the three axial directions to assess the anisotropy of these transport properties. These computational results were compared to laboratory measurements. The computed effective bulk density, grain density, and porosity appeared to closely match the laboratory values. So did the formation factor. By selecting an appropriate grain size, we also

  20. The durability of Božanov sandstone – simulation of Prague winter climatic conditions

    Directory of Open Access Journals (Sweden)

    Kateřina Kovářová

    2011-06-01

    Full Text Available Sandstones were often used mainly as building material in Prague. Weathering processes lead to deterioration of these dimension stones and to changes in their durability. The range of the deterioration depends on petrography, including internal structure, mineral and matrix composition, and also changes initiated. The stone’s properties are negatively influenced especially during the winter frost period, and the presence of salt can exacerbate this process. The national standardized testing methods for natural stone, such as determination of frost resistance and determination of resistance to salt crystallisation may not take into consideration the actual conditions in the stone’s locality. Road salts, mainly composed of sodium chloride, are used to de-ice streets in Prague during winter season. Samples of snow/water mixtures from Prague city centre were chemically analyzed and the average NaCl concentration was determined. To simulate the weathering processes typical in Prague’s winter climatic conditions, seasonal data from 1999 to 2008 were statistically analyzed. Based on this analysis, a simulation program consisting of 56 freeze/thaw cycles in the temperature range of -14°C to 14°C was developed. The weathering simulation program was divided into four stages, each consisting of 14 freeze/thaw cycles. The sandstone samples had been soaked for 24 hours in distilled water and in a 2.5% solution of NaCl before each stage. Each cycle lasted seven hours and the samples were maintained at minimal and maximal temperatures for two hours. The Božanov Cretaceous sandstone was tested during this experiment. Changes developing in the internal structure were studied by Hg porosimetry. Physical-mechanical properties such as water absorption at atmospheric pressure, uniaxial compressive strength, apparent density and open porosity were also studied. The uniaxial compressive strength decreased after 56 freeze/thaw cycles in both combinations

  1. EFFECT OF SANDSTONE ANISOTROPY ON ITS HEAT AND MOISTURE TRANSPORT PROPERTIES

    Directory of Open Access Journals (Sweden)

    Jan Fořt

    2015-09-01

    Full Text Available Each type of natural stone has its own geological history, formation conditions, different chemical and mineralogical composition, which influence its possible anisotropy. Knowledge in the natural stones anisotropy represents crucial information for the process of stone quarrying, its correct usage and arrangement in building applications. Because of anisotropy, many natural stones exhibit different heat and moisture transport properties in various directions. The main goal of this study is to analyse several anisotropy indices and their effect on heat transport and capillary absorption. For the experimental determination of the anisotropy effect, five types of sandstone coming from different operating quarries in the Czech Republic are chosen. These materials are often used for restoration of culture heritage monuments as well as for other building applications where they are used as facing slabs, facade panels, decoration stones, paving, etc. For basic characterization of studied materials, determination of their bulk density, matrix density and total open porosity is done. Chemical composition of particular sandstones is analysed by X-Ray Fluorescence. Anisotropy is examined by the non-destructive measurement of velocity of ultrasonic wave propagation. On the basis of ultrasound testing data, the relative anisotropy, total anisotropy and anisotropy coefficient are calculated. Then, the measurement of thermal conductivity and thermal diffusivity in various directions of samples orientation is carried out. The obtained results reveal significant differences between the parameters characterizing the heat transport in various directions, whereas these values are in accordance with the indices of anisotropy. Capillary water transport is described by water absorption coefficient measured using a sorption experiment, which is performed for distilled water and 1M NaCl water solution.  The measured data confirm the effect of anisotropy which is

  2. Selective sandstone deterioration in the cathedrals of Salamanca, Textural anisotropy as a cause

    Directory of Open Access Journals (Sweden)

    Martín Patino, María Teresa

    1994-09-01

    Full Text Available Textural sandstone anisotropy is related to the selective deterioration of such stone in buildings. The samples studied come from the Cathedrals of Salamanca. Stone fragments, cut in different directions with regard to the base supporting the ashlars in the wall, are studied by means of a binocular magnifying glass and the Scanning Electron Microscopy (SEM. This shows that the sandstone microfabric has a granular and a laminar microtexture, which correspond to different directions in the plane in question as regards the position of the ashlar. Either of these circumstances coincides with the stone surface on the outside of the building and affect its surface deterioration in a different way. The SEM images of deteriorated stone were compared with those of unaffected stone, with both types coming from differently orientated cuts as regards the position of the ashlar. In conclusion, the position given to the block of stone in the building is of importance for the preservation of the stone. The speed of ultrasound transmission measured in samples from commercial quarries confirms the textural sandstone anisotropy to a greater or lesser extent.

    La anisotropía textural de las areniscas se relaciona con la selectividad de su deterioro en los edificios. Las muestras estudiadas pertenecen a las Catedrales de Salamanca. Fragmentos de piedra, cortados en direcciones diferentes respecto a la base sobre la que se asientan los sillares en el muro, son estudiados por medio de la lupa binocular y del microscopio electrónico de barrido (SEM. De éstos se deduce que la microfábrica de las areniscas tiene una microtextura granular y otra laminar, que corresponden a direcciones diferentes del plano respecto al asiento del sillar. Una u otra de estas situaciones coincide con la superficie de la piedra expuesta al exterior en el edificio, y afectan a su deterioro superficial de forma diferente. Las capas externas en las que predomina la arcilla

  3. Genesis Analysis of High-Gamma Ray Sandstone Reservoir and Its Log Evaluation Techniques: A Case Study from the Junggar Basin, Northwest China

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2013-01-01

    Full Text Available In the Junggar basin, northwest China, many high gamma-ray (GR sandstone reservoirs are found and routinely interpreted as mudstone non-reservoirs, with negative implications for the exploration and exploitation of oil and gas. Then, the high GR sandstone reservoirs’ recognition principles, genesis, and log evaluation techniques are systematically studied. Studies show that the sandstone reservoirs with apparent shale content greater than 50% and GR value higher than 110API can be regarded as high GR sandstone reservoir. The high GR sandstone reservoir is mainly and directly caused by abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. Affected by formation’s high water sensitivity and poor borehole quality, the conventional logs can not recognize reservoir and evaluate the physical property of reservoirs. Then, the nuclear magnetic resonance (NMR logs is proposed and proved to be useful in reservoir recognition and physical property evaluation.

  4. Genesis analysis of high-gamma ray sandstone reservoir and its log evaluation techniques: a case study from the Junggar basin, northwest China.

    Science.gov (United States)

    Wang, Liang; Mao, Zhiqiang; Sun, Zhongchun; Luo, Xingping; Song, Yong; Liu, Zhen

    2013-01-01

    In the Junggar basin, northwest China, many high gamma-ray (GR) sandstone reservoirs are found and routinely interpreted as mudstone non-reservoirs, with negative implications for the exploration and exploitation of oil and gas. Then, the high GR sandstone reservoirs' recognition principles, genesis, and log evaluation techniques are systematically studied. Studies show that the sandstone reservoirs with apparent shale content greater than 50% and GR value higher than 110API can be regarded as high GR sandstone reservoir. The high GR sandstone reservoir is mainly and directly caused by abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. Affected by formation's high water sensitivity and poor borehole quality, the conventional logs can not recognize reservoir and evaluate the physical property of reservoirs. Then, the nuclear magnetic resonance (NMR) logs is proposed and proved to be useful in reservoir recognition and physical property evaluation.

  5. Mineralogy, provenance, and diagenesis of a potassic basaltic sandstone on Mars: CheMin X‐ray diffraction of the Windjana sample (Kimberley area, Gale Crater)

    Science.gov (United States)

    Bish, David L.; Vaniman, David T.; Chipera, Steve J.; Blake, David F.; Ming, Doug W.; Morris, Richard V.; Bristow, Thomas F.; Morrison, Shaunna M.; Baker, Michael B.; Rampe, Elizabeth B.; Downs, Robert T.; Filiberto, Justin; Glazner, Allen F.; Gellert, Ralf; Thompson, Lucy M.; Schmidt, Mariek E.; Le Deit, Laetitia; Wiens, Roger C.; McAdam, Amy C.; Achilles, Cherie N.; Edgett, Kenneth S.; Farmer, Jack D.; Fendrich, Kim V.; Grotzinger, John P.; Gupta, Sanjeev; Morookian, John Michael; Newcombe, Megan E.; Rice, Melissa S.; Spray, John G.; Stolper, Edward M.; Sumner, Dawn Y.; Vasavada, Ashwin R.; Yen, Albert S.

    2016-01-01

    Abstract The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X‐ray diffraction (XRD) in the MSL Curiosity rover. From Rietveld refinements of its XRD pattern, Windjana contains the following: sanidine (21% weight, ~Or95); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); and percent levels of others including ilmenite, fluorapatite, and bassanite. From mass balance on the Alpha Proton X‐ray Spectrometer (APXS) chemical analysis, the amorphous material is Fe rich with nearly no other cations—like ferrihydrite. The Windjana sample shows little alteration and was likely cemented by its magnetite and ferrihydrite. From ChemCam Laser‐Induced Breakdown Spectrometer (LIBS) chemical analyses, Windjana is representative of the Dillinger and Mount Remarkable members of the Kimberley formation. LIBS data suggest that the Kimberley sediments include at least three chemical components. The most K‐rich targets have 5.6% K2O, ~1.8 times that of Windjana, implying a sediment component with >40% sanidine, e.g., a trachyte. A second component is rich in mafic minerals, with little feldspar (like a shergottite). A third component is richer in plagioclase and in Na2O, and is likely to be basaltic. The K‐rich sediment component is consistent with APXS and ChemCam observations of K‐rich rocks elsewhere in Gale Crater. The source of this sediment component was likely volcanic. The presence of sediment from many igneous sources, in concert with Curiosity's identifications of other igneous materials (e.g., mugearite), implies that the northern rim of Gale Crater exposes a diverse igneous complex, at least as diverse as that found in similar‐age terranes on Earth. PMID:27134806

  6. Mineralogy, provenance, and diagenesis of a potassic basaltic sandstone on Mars: CheMin X-ray diffraction of the Windjana sample (Kimberley area, Gale Crater)

    Science.gov (United States)

    Treiman, Allan H.; Bish, David L.; Vaniman, David T.; Chipera, Steve J.; Blake, David F.; Ming, Doug W.; Morris, Richard V.; Bristow, Thomas F.; Morrison, Shaunna M.; Baker, Michael B.; Rampe, Elizabeth B.; Downs, Robert T.; Filiberto, Justin; Glazner, Allen F.; Gellert, Ralf; Thompson, Lucy M.; Schmidt, Mariek E.; Le Deit, Laetitia; Wiens, Roger C.; McAdam, Amy C.; Achilles, Cherie N.; Edgett, Kenneth S.; Farmer, Jack D.; Fendrich, Kim V.; Grotzinger, John P.; Gupta, Sanjeev; Morookian, John Michael; Newcombe, Megan E.; Rice, Melissa S.; Spray, John G.; Stolper, Edward M.; Sumner, Dawn Y.; Vasavada, Ashwin R.; Yen, Albert S.

    2016-01-01

    The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X-ray diffraction (XRD) in the MSL Curiosity rover. From Rietveld refinements of its XRD pattern, Windjana contains the following: sanidine (21% weight, ~Or95); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); and percent levels of others including ilmenite, fluorapatite, and bassanite. From mass balance on the Alpha Proton X-ray Spectrometer (APXS) chemical analysis, the amorphous material is Fe rich with nearly no other cations—like ferrihydrite. The Windjana sample shows little alteration and was likely cemented by its magnetite and ferrihydrite. From ChemCam Laser-Induced Breakdown Spectrometer (LIBS) chemical analyses, Windjana is representative of the Dillinger and Mount Remarkable members of the Kimberley formation. LIBS data suggest that the Kimberley sediments include at least three chemical components. The most K-rich targets have 5.6% K2O, ~1.8 times that of Windjana, implying a sediment component with >40% sanidine, e.g., a trachyte. A second component is rich in mafic minerals, with little feldspar (like a shergottite). A third component is richer in plagioclase and in Na2O, and is likely to be basaltic. The K-rich sediment component is consistent with APXS and ChemCam observations of K-rich rocks elsewhere in Gale Crater. The source of this sediment component was likely volcanic. The presence of sediment from many igneous sources, in concert with Curiosity's identifications of other igneous materials (e.g., mugearite), implies that the northern rim of Gale Crater exposes a diverse igneous complex, at least as diverse as that found in similar-age terranes on Earth.

  7. Board Members' Views on Training and Development.

    Science.gov (United States)

    Weaver, Liz; Inglis, Sue

    1999-01-01

    A survey of 22 agency directors and 219 volunteer board members showed that 40% of members received 1-5 hours of training in the last 6 months, 47% none. Training needs included board roles and responsibilities, strategic planning, understanding the agency, and fundraising. Preferred methods were facilitated workshop/retreat or board-led training…

  8. 51 CAS Members Elected in 2005

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Atotal of 51 prominent Chinese scientists were elected CAS members in 2005. The announce ment was made at a press conference held on Dec. 16 in Beijing. CAS President LU Yongxiang was present at the conference to give a briefing on the election and the new members.

  9. Educational Faculty Members' Perceptions on Multicultural Teacher

    Science.gov (United States)

    Günay, Rafet; Aslan, Dolgun

    2016-01-01

    This purpose of this study is to determine how the perceptions of teaching personnel members were conceptualized through use of metaphorical images with regard to the multicultural teacher. In this study, a phenomenological design, a type of qualitative research design was used. A total of 323 teaching personnel members employed at 71 educational…

  10. State School Board Members and Educational Policy

    Science.gov (United States)

    Sroufe, Gerald E.

    1970-01-01

    Research evidence suggests that changes in selection criteria for State board members would increase their effectiveness, more so than changes in either the selection criteria for school board members or in the relationship between the chief school officer and the State board. (Author/LR)

  11. School Board Member Recruitment in Ontario.

    Science.gov (United States)

    Cistone, Peter J.

    Employing a process model of political recruitment, this study investigated the relative impact of a school district's social, economic, and political structure on school board member recruitment. The process data were collected by means of structured interviews with neophyte school board members in a stratified sample of school boards in the…

  12. 7 CFR 1425.14 - Member business.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Member business. 1425.14 Section 1425.14 Agriculture... business. (a) At least 50 percent of a crop of an authorized commodity acquired by, or delivered to, a CMA... not be considered in determining the volume of member or nonmember business....

  13. CERN Member States signatures at LEP inauguration

    CERN Multimedia

    1989-01-01

    The signatures of the dignitaries who represented CERN's Member States on the occasion of the Inauguration of LEP on 13 November 1989. The Large Electron-Positron (LEP) collider was inaugurated in the presence of some 1500 guests, including Heads of State and Ministers from all of CERN's 14 Member States.

  14. Methods of Assessment for Affected Family Members

    Science.gov (United States)

    Orford, Jim; Templeton, Lorna; Velleman, Richard; Copello, Alex

    2010-01-01

    The article begins by making the point that a good assessment of the needs and circumstances of family members is important if previous neglect of affected family members is to be reversed. The methods we have used in research studies are then described. They include a lengthy semi-structured interview covering seven topic areas and standard…

  15. Hymenobacter roseosalivarius gen. nov., sp. nov. from continental Antartica soils and sandstone: bacteria of the Cytophaga/Flavobacterium/Bacteroides line of phylogenetic descent.

    Science.gov (United States)

    Hirsch, P; Ludwig, W; Hethke, C; Sittig, M; Hoffmann, B; Gallikowski, C A

    1998-08-01

    Aseptically collected sandstone and soil samples from the antarctic Dry Valleys were inoculated into oligotrophic media and incubated under low light intensities. A total of 41 Gram-negative isolates were obtained with reddish colonies spreading on agar. A sandstone isolate and four soil strains were characterized further. They were nearly identical in morphological, physiological, biochemical and chemotaxonomic properties. They produced large amounts of extracellular polymer and utilized for growth: glucose, saccharose, mannitol, sorbitol, L-aspartate, malate and acetate, but not D-ribose, adonitol, DL-alanine, glutamate, glycolate, lactate or succinate. All strains hydrolyzed gelatin, starch, casein, xylan, Tweens 80 or 60 and dead or living yeast cells, but not cellulose or pectin. Nitrate was not reduced, ethanol was not oxidized and acid was not produced from maltose, mannitol or dulcitol. Ammonia was not produced from peptone. They were strictly aerobic. Major fatty acids were n 16:1 d 9, n 16:1 d 11, n 17:1 d 11, and i 15:0. The strains contained the quinone MK-7 and phosphatidylethanolamine as the main phospholipid. The base ratio ranged from 55 to 61 mol% G+C. A 16S rRNA sequence analysis of strains AA-688 and AA-718 showed these to be identical and to represent a special phylogenetic group within the Cytophaga/Flavobacterium/Bacteroides major line of descent. Three soil strains labeled "Taxeobacter" Txc1, Txg1, and Txo1 (Reichenbach, 1992) belonged to the same group but had lower sequence similarities (<95%). Some of their characteristics were different from those of the antarctic strains: the utilization of C-compounds, hydrolysis of polymers, temperature tolerances, major fatty acids and base ratios. Txc1 and Txg1 may later have to be considered as members of this group, possibly on the species level, while Txo1 could represent a different related genus. It is concluded that the five antarctic strains represent a new genus and species for which the name

  16. Mineralogy and Genesis of the Windjana Sandstone, Kimberley Area, Gale Crater, Mars

    Science.gov (United States)

    Treiman, A. H.; Bish, D.; Ming, D. W.; Grotzinger, J.; Vaniman, D. T.; Baker, M. B.; Farmer, J.; Chipera, S.; Downs, R. T.; Morris, R. V.; Rampe, E.; Blake, D. F.; Berger, J.; Cavanagh, P. D.; Gellert, R.; Glazner, A. F.; Schmidt, M.; Yen, A. S.; Filiberto, J.

    2015-01-01

    MSL Curiosity investigated the Windjana sandstone outcrop, in the Kimberley area of Gale Crater, and obtained mineralogical analyses with the CheMin XRD instrument. Windjana is remarkable in containing an abundance of potassium feldspar (and thus K in its bulk chemistry) combined with a low abundance of plagioclase (and low Na/K in its chemistry). The source of this enrichment in K is not clear, but has significant implications for the geology of Gale Crater and of Mars. The high K could be intrinsic to the sediment and imply that the sediment source area (Gale Crater rim) includes K-rich basalts and possibly more evolved rocks derived from alkaline magmas. Alternatively, the high K could be diagenetic and imply that the Gale Crater sediments were altered by K-rich aqueous fluids after deposition.

  17. Frequency, pressure, and strain dependence of nonlinear elasticity in Berea Sandstone

    Science.gov (United States)

    Rivière, Jacques; Pimienta, Lucas; Scuderi, Marco; Candela, Thibault; Shokouhi, Parisa; Fortin, Jérôme; Schubnel, Alexandre; Marone, Chris; Johnson, Paul A.

    2016-04-01

    Acoustoelasticity measurements in a sample of room dry Berea sandstone are conducted at various loading frequencies to explore the transition between the quasi-static (f→0) and dynamic (few kilohertz) nonlinear elastic response. We carry out these measurements at multiple confining pressures and perform a multivariate regression analysis to quantify the dependence of the harmonic content on strain amplitude, frequency, and pressure. The modulus softening (equivalent to the harmonic at 0f) increases by a factor 2-3 over 3 orders of magnitude increase in frequency. Harmonics at 2f, 4f, and 6f exhibit similar behaviors. In contrast, the harmonic at 1f appears frequency independent. This result corroborates previous studies showing that the nonlinear elasticity of rocks can be described with a minimum of two physical mechanisms. This study provides quantitative data that describes the rate dependency of nonlinear elasticity. These findings can be used to improve theories relating the macroscopic elastic response to microstructural features.

  18. Selective silicification of fossils by syntaxial overgrowths on quartz sand, Oriskany Sandstone (Lower Devonian), New York

    Science.gov (United States)

    Maliva, Robert G.

    1992-07-01

    Some fossil fragments in the Oriskany Sandstone (Lower Devonian) of New York were partially replaced by syntaxial quartz overgrowths. These replacive overgrowths are significant in that they provide insights into the mechanism and controls of quartz replacement of calcite. The susceptibility of the different calcite types of quartz replacement was governed by their microstructural complexity. Fossil fragments with finely crystalline microstructures, such as brachiopods, ostracods, and bryozoans, were partially replaced by quartz, whereas echinoderm ossicles, which consist of single large calcite crystals, were not replaced. Calcite cement was also immune to replacement. Brachiopod, bryozoan, and ostracod bioclasts (with minor exceptions) underwent partial replacement by quartz (with its concomitant shell calcite dissolution) only where the shell fragments were in contact with detrital quartz grains. Proximity to authigenic crystal nucleation sites (i.e., quartz sand grains) was thus the prime control over whether host mineral dissolution occurred, which is a situation unique to the force of crystallization-driven replacement mechanism.

  19. Numerical modelling of sandstone uniaxial compression test using a mix-mode cohesive fracture model

    CERN Document Server

    Gui, Yilin; Kodikara, Jayantha

    2015-01-01

    A mix-mode cohesive fracture model considering tension, compression and shear material behaviour is presented, which has wide applications to geotechnical problems. The model considers both elastic and inelastic displacements. Inelastic displacement comprises fracture and plastic displacements. The norm of inelastic displacement is used to control the fracture behaviour. Meantime, a failure function describing the fracture strength is proposed. Using the internal programming FISH, the cohesive fracture model is programmed into a hybrid distinct element algorithm as encoded in Universal Distinct Element Code (UDEC). The model is verified through uniaxial tension and direct shear tests. The developed model is then applied to model the behaviour of a uniaxial compression test on Gosford sandstone. The modelling results indicate that the proposed cohesive fracture model is capable of simulating combined failure behaviour applicable to rock.

  20. Dynamic response of berea sandstone shock-loaded under dry, wet and water-pressurized conditions

    Energy Technology Data Exchange (ETDEWEB)

    Carney, T C; Hagelberg, C R; Hilt, M; Nellis, W J; Swift, R P

    1999-09-03

    A single-stage light-gas gun was used to perform shock-recovery experiments on Berea sandstone under dry, wet and hydrostatically water-pressurized conditions. The samples were impacted by flyer-plates to achieve stress levels in the range 1.3 to 9.8 GPa. The microstructure of the shocked samples was analyzed using scanning electron microscopy (SEM), laser particle analysis and X-ray computed microtomography (XCMT). The dry samples show strongly fragmented and irregularly fractured quartz grains with a considerably reduced porosity, whereas the wet and water-pressurized specimens show less grain damage and less porosity reduction. During shock compression the water in the pores distributes the stresses and therefore the contact force between the grains is reduced. The interaction between the grains during the shock process was modeled by explicitly treating the grain-pore structure using Smooth Particle Hydrodynamics (SPH) and the Discrete Element Method (DEM).

  1. Numerical study of AE and DRA methods in sandstone and granite in orthogonal loading directions

    Directory of Open Access Journals (Sweden)

    Xu-hua REN

    2012-03-01

    Full Text Available The directional dependency of the acoustic emission (AE and deformation rate analysis (DRA methods was analyzed, based on the contact bond model in the two-dimensional particle flow code (PFC2D in two types of rocks, the coarse-grained sandstone and Aue granite. Each type of rocks had two shapes, the Brazilian disk and a square shape. The mechanical behaviors of the numerical model had already been verified to be in agreement with those of the physical specimens in previous research. Three loading protocols with different loading cycles in two orthogonal directions were specially designed in the numerical tests. The results show that no memory effect is observed in the second loading in the orthogonal direction. However, both the cumulative crack number of the second loading and the differential strain value at the inflection point are influenced by the first loading in the orthogonal direction.

  2. A buffer-regulated HF acid for sandstone acidizing to 550/sup 0/F

    Energy Technology Data Exchange (ETDEWEB)

    Scheuerman, R.F.

    1988-02-01

    Two earlier papers discussed the suitability of bugger-regulated HF acid (BRHFA) for high-temperature sandstone matrix stimulation treatments. Acetic-acid/acetate buffering (pH = 4.5 to 5.0) limited corrosion to acceptable levels at temperatures up to about 350/sup 0/F (177/sup 0/C). Subsequent development of reservoirs with temperatures approaching 450/sup 0/F (232/sup 0/C) demonstrated a need for even higher-temperature acidizing systems. This paper discusses a new, less corrosive BRHFA formulation that has clay-dissolving capacity comparable to 7 1/2% HCl/1 1/2% HF acid. The corrosion rate of carbon steel at 550/sup 0/F (288/sup 0/C) is only 330 mils/yr (8.4 mm/a). The BRHFA systems are also compatible with a variety of corrosion-resistant alloys. This paper presents clay slurry, core flow, and corrosion data and discusses use guidelines.

  3. Fission track dating of mesozoic sandstones and its tectonic significance in the Eastern Sichuan Basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Shen Chuanbo, E-mail: cugshen@yahoo.c [Key Laboratory of Tectonics and Petroleum Resources, China University of Geosciences, Ministry of Education, Wuhan 430074 (China); Faculty of Earth Resources, China University of Geosciences, Wuhan, Hubei Province 430074 (China); Mei Lianfu [Key Laboratory of Tectonics and Petroleum Resources, China University of Geosciences, Ministry of Education, Wuhan 430074 (China); Xu Sihuang [Faculty of Earth Resources, China University of Geosciences, Wuhan, Hubei Province 430074 (China)

    2009-10-15

    To establish the tectonic evolution of the eastern Sichuan basin, apatite fission track dating and time-temperature thermal history modeling were carried to analyze on 11 samples collected from Jurassic sandstones. The results indicate that the cooling and exhumation process of the eastern Sichuan basin can be divided into three stages since Cretaceous, (1) a rapid cooling phase between approx100 and approx70 Ma, (2) following by a period of relative thermal stability phase between approx70 and approx15 Ma, (3) and then a new rapid cooling stage after approx15 Ma. Two rapid cooling events imply that the eastern Sichuan basin once underwent two tectonic movements since Cretaceous. The first rapid cooling is associated with Mesozoic tectonic reactivation beginning at 100 Ma, which result in folds and faults of the eastern Sichuan basin. The second tectonic movement occurred at 15 Ma, which is related to denudation by compression resulting from the eastward growth of Tibetan plateau uplift.

  4. Natural baseline quality within the Lower Triassic Sandstone of Lorraine (France): Status and evolution

    International Nuclear Information System (INIS)

    The Triassic sandstones, that form an important aquifer on the Eastern border of the Paris Basin (France), have been intensively exploited by large scale pumping begun in the seventies that created a significant decrease in head level. Investigations using a combination of geochemical and isotopic methods have been carried out in 1979 and interpreted in terms of residence time of groundwater. This area appeared then of a special interest regarding the groundwater baseline evolution related to overexploitation and matches the objectives of the EU BaScLiNc project EVK1-1999- 00024 as it allows to establish long term trends in water quality of a deep groundwater system. A new field campaign (major, minor, trace elements and isotopes) was started in 2001 in order to highlight the modifications of the water quality in relation with the modifications of the piezometric levels and the circulation flow paths that occurred after the large scale pumping. (author)

  5. Microstructure parameters evaluation of Botucatu formation sandstone by X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Jaquiel S.; Appoloni, Carlos R.; Marques, Leonardo C., E-mail: jaquielfernandes@yahoo.com.b, E-mail: appoloni@uel.b, E-mail: leocarma@yahoo.com.b [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. de Fisica. Lab. de Fisica Nuclear Aplicada; Fernandes, Celso P., E-mail: celso@lmpt.ufsc.b [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Meios Porosos e Propriedades TermoFisicas (LMPT)

    2009-07-01

    Microstructural parameters evaluation of reservoir rocks are very important to petroleum industry. This work presents total porosity and pore size distribution measurement of a silicified sandstone sample from the Botucatu formation, collected at municipal district of Faxinal, Parana, Brazil. Porosity and pores size distribution were determined using X-Ray microtomography and imaging techniques. Acquired images had 2.9 mum spatial resolution. 800 2-D images where reconstructed for the microstructure analysis. The determined average porosity was 6.1 +- 2.1 %. 95 % of the porous phase refers to pores with radius ranging from 2.9 to 167.4 mum, presenting the larger frequency (6 %) at 5.9 mum radius. The 3-D volume of the sample was reconstructed and compared with the 3-D model obtained through the autocorrelation functions from the 2-D images analysis. (author)

  6. Cyclicity recorded in the provenance sandstones in the sedimentary in fill of the Cameros basin (N. Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Acebron, L.; Arribas, J.; Omodeo-Sale, S.; Arribas, E.; Le Pera, E.; Mas, R.; Lopez-Elorza, M.; Fernandez-Diaz, P. R.

    2013-06-01

    The intra plate Cameros rift basin in the north of Spain was formed came into being between the Tithonian and the Early Albian and contains 9 000 m of mostly continental sediments. This basin is a good example of cyclicity of different depositional sequences (DSs) in sedimentary environments, which show clear repetition in their sandstone composition (petrofacies) and diagenetic patterns. The DSs are arranged in two mega sequences (MSs) separated by a tectonic unconformity. A similar vertical sandstone compositional evolution, subdivided into two stages that repeat cyclically, has been recognised in both MSs: the first comprises quartzo-sedimentolithic petrofacies and the second is made up of several quartzo-feldspathic petrofacies. This was caused by a progression from the recycling of the pre-rift sedimentary cover to the erosion of the mainly plutonic and metamorphic crystalline basement. These changes in the erosion of the different source areas were conditioned by the tectonics of the basin. Furthermore, the original sandstone framework composition conditioned the diagenetic pattern of the two stages: quartzo-sedimentolithic sandstones containing large amounts of very pervasive carbonate cement that reduce their original porosity considerably, and quartzo-feldspathic petrofacies with a rigid framework that maintained the original pores during burial diagenesis. This compositional and diagenetic pattern is probably applicable to other non-volcanic rifted basins, depending upon the original amount of carbonate rock fragments present. (Author)

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

    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.

  8. Geology and recognition criteria for sandstone uranium deposits in mixed fluvial-shallow marine sedimentary sequences, South Texas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Adams, S.S.; Smith, R.B.

    1981-01-01

    Uranium deposits in the South Texas Uranium Region are classical roll-type deposits that formed at the margin of tongues of altered sandstone by the encroachment of oxidizing, uraniferous solutions into reduced aquifers containing pyrite and, in a few cases, carbonaceous plant material. Many of the uranium deposits in South Texas are dissimilar from the roll fronts of the Wyoming basins. The host sands for many of the deposits contain essentially no carbonaceous plant material, only abundant disseminated pyrite. Many of the deposits do not occur at the margin of altered (ferric oxide-bearing) sandstone tongues but rather occur entirely within reduced, pyurite-bearing sandstone. The abundance of pyrite within the sands probably reflects the introduction of H/sub 2/S up along faults from hydrocarbon accumulations at depth. Such introductions before ore formation prepared the sands for roll-front development, whereas post-ore introductions produced re-reduction of portions of the altered tongue, leaving the deposit suspended in reduced sandstone. Evidence from three deposits suggests that ore formation was not accompanied by the introduction of significant amounts of H/sub 2/S.

  9. Frio sandstone reservoirs in the deep subsurface along the Texas Gulf Coast: their potential for production of geopressured geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Bebout, D.G.; Loucks, R.G.; Gregory, A.R.

    1983-01-01

    Detailed geological, geophysical, and engineering studies conducted on the Frio Formation have delineated a geothermal test well site in the Austin Bayou Prospect which extends over an area of 60 square miles. A total of 800 to 900 feet of sandstone will occur between the depths of 13,500 and 16,500 feet. At leat 30 percent of the sand will have core permeabilities of 20 to 60 millidarcys. Temperature at the top of the sandstone section will be 300/sup 0/F. Water, produced at a rate of 20,000 to 40,000 barrels per day, will probably have to be disposed of by injection into shallower sandstone reservoirs. More than 10 billion barrels of water are in place in these sandstone reservoirs of the Austin Bayou Prospect; there should be approximately 400 billion cubic feet of methane in solution in this water. Only 10 percent of the water and methane (1 billion barrels of water and 40 billion cubic feet of methane) will be produced without reinjection of the waste water into the producing formation. Reservoir simulation studies indicate that 90 percent of the methane can be produced with reinjection. 106 figures.

  10. Geology and recognition criteria for sandstone uranium deposits in mixed fluvial-shallow marine sedimentary sequences, South Texas. Final report

    International Nuclear Information System (INIS)

    Uranium deposits in the South Texas Uranium Region are classical roll-type deposits that formed at the margin of tongues of altered sandstone by the encroachment of oxidizing, uraniferous solutions into reduced aquifers containing pyrite and, in a few cases, carbonaceous plant material. Many of the uranium deposits in South Texas are dissimilar from the roll fronts of the Wyoming basins. The host sands for many of the deposits contain essentially no carbonaceous plant material, only abundant disseminated pyrite. Many of the deposits do not occur at the margin of altered (ferric oxide-bearing) sandstone tongues but rather occur entirely within reduced, pyurite-bearing sandstone. The abundance of pyrite within the sands probably reflects the introduction of H2S up along faults from hydrocarbon accumulations at depth. Such introductions before ore formation prepared the sands for roll-front development, whereas post-ore introductions produced re-reduction of portions of the altered tongue, leaving the deposit suspended in reduced sandstone. Evidence from three deposits suggests that ore formation was not accompanied by the introduction of significant amounts of H2S

  11. Elastic moduli of sandstones saturated with a range of pore fluids correlated with kinematic viscosity and frequency ratio

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2011-01-01

    . The purpose of this study is to investigate if frame parameters can be extracted from air saturated measurements in sandstones, because earlier studies have shown that air may have a non-negligible effect on carbonates due to the high kinematic viscosity of air (Fabricius et al., 2010)....

  12. Depositional and diagenetic variability within the Cambrian Mount Simon Sandstone: Implications for carbon dioxide sequestration

    Science.gov (United States)

    Bowen, B.B.; Ochoa, R.I.; Wilkens, N.D.; Brophy, J.; Lovell, T.R.; Fischietto, N.; Medina, C.R.; Rupp, J.A.

    2011-01-01

    The Cambrian Mount Simon Sandstone is the major target reservoir for ongoing geologic carbon dioxide (CO2) sequestration demonstrations throughout the midwest United States. The potential CO2 reservoir capacity, reactivity, and ultimate fate of injected CO2 depend on textural and compositional properties determined by depositional and diagenetic histories that vary vertically and laterally across the formation. Effective and efficient prediction and use of the available pore space requires detailed knowledge of the depositional and diagenetic textures and mineralogy, how these variables control the petrophysical character of the reservoir, and how they vary spatially. Here, we summarize the reservoir characteristics of the Mount Simon Sandstone based on examination of geophysical logs, cores, cuttings, and analysis of more than 150 thin sections. These samples represent different parts of the formation and depth ranges of more than 9000 ft (>2743 m) across the Illinois Basin and surrounding areas. This work demonstrates that overall reservoir quality and, specifically, porosity do not exhibit a simple relationship with depth, but vary both laterally and with depth because of changes in the primary depositional facies, framework composition (i.e., feldspar concentration), and diverse diagenetic modifications. Diagenetic processes that have been significant in modifying the reservoir include formation of iron oxide grain coatings, chemical compaction, feldspar precipitation and dissolution, multiple generations of quartz overgrowth cementation, clay mineral precipitation, and iron oxide cementation. These variables provide important inputs for calculating CO2 capacity potential, modeling reactivity, and are also an important baseline for comparisons after CO2 injection. Copyright ??2011. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

  13. Endolithic diversity of microorganisms on sandstone and implications for biogenic weathering

    Science.gov (United States)

    Hallmann, C.; Friedenberger, H.; Hoppert, M.

    2012-04-01

    Molecular methods allow a comprehensive view on uncultured microbial communities in dimension stone. In the presented study, we focus on depth profiles of microbial colonization in sandstones with different porosity and overall durability. All sandstones were taken from quarries where they were exposed to the environment for several years. Approximately 0.1 g of material from the stone surface, from 5 mm and from 30 mm depths was taken under sterile conditions and subjected to analysis of microbial DNA and culturing experiments. In particular, DNA was extracted from the material, the phylogenetic marker gene of eukaryotic organisms (18S rDNA) was amplified and used for generation of clone libraries, which were then analysed by sequencing. "Roter Wesersandstein" was just colonized at the material surface, predominantly with algal and fungal microorganisms. No environmental DNA could be isolated from depth profiles. From "Nebraer Sandstein" with high pore size (shown by thin sections), environmental DNA from depths down to 3 cm could be retrieved. Though the uppermost layer is dominated by microalgae (as concluded from the retrieved clones), the percentage of algal clones from 5 mm and 30 mm depths drop to 10 % of all clones. There, apart from filamentous fungi, moss clones clearly dominate the microbial community. At a depth of 30 mm, 70-80 % of the retrieved clones match to various mosses (Bryophyta). Though mosses do not form layers on the stone surfaces, moss rhizoids or protonemata must be abundant as endoliths inside the stone material. It is reasonable to assume that the rhizoids may contribute to an increase in pore size by active penetration of the clastic material, even though colonization of the surface by mosses is not obvious. This feature may imply stronger impact of stone decay induced by endolithic growth of bryophytes than hitherto observed.

  14. Lithologic characteristics and diagenesis of the Devonian Jauf sandstone at Ghawar Field, Eastern Saudi Arabia

    Energy Technology Data Exchange (ETDEWEB)

    Al Ramadan, K.A.; Hussain, M. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Earth Sciences; Imam, B. [Dhaka Univ. (Bangladesh). Dept. of Geology; Saner, S. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Research Inst.

    2004-12-01

    The Lower Devonian Jauf Formation in Saudi Arabia is an important hydrocarbon reservoir. However, in spite of its importance as a reservoir, published studies on the Jauf Formation more specifically on the reservoir quality (including diagenesis), are very few. This study, which is based on core samples from two wells in the Ghawar Field, northeastern Saudi Arabia, reports the lithologic and diagenetic characteristics of this reservoir. The Jauf reservoir is a fine to medium-grained, moderate to well-sorted quartz arenite. The diagenetic processes recognized include compaction, cementation (calcite, clay minerals, quartz overgrowths, and a minor amount of pyrite), and dissolution of the calcite cements and of feldspar grains. The widespread occurrences of early calcite cement suggest that the Jauf reservoir lost a significant amount of primary porosity at a very early stage of its diagenetic history. Early calcite cement, however, prevented the later compaction of the sandstone, thus preserving an unfilled part of the primary porosity. Based on the framework grain-cement relationships, precipitation of the early calcite cement was either accompanied or followed by the development of part of the pore-lining and pore-bridging clay cement. Secondary porosity development occurred due to partial to complete dissolution of early calcite cements and feldspar. Late calcite cement occurs as isolated patches, and has little impact on reservoir quality of the sandstones. In addition to calcite, several different clay minerals including illite and chlorite occur as pore-filling and pore-lining cements. While the pore-filling illite and chlorite resulted in a considerable loss of porosity, the pore-lining chlorite may have helped in retaining the porosity by preventing the precipitation of syntaxial quartz overgrowths. Illite, which largely occurs as hair-like rims around the grains and bridges on the pore throats, caused a substantial deterioration to permeability of the

  15. [Species Determination and Spectral Characteristics of Swelling Clay Minerals in the Pliocene Sandstones in Xinghai, Qinghai].

    Science.gov (United States)

    Wang, Chao-wen; Chen, Jiang-jun; Fang, Qian; Yin, Ke; Hong, Han-lie

    2015-10-01

    X-ray diffraction (XRD) and Fourier infrared absorption spectroscopy (FTIR) were conducted to deepen our research on specific species and spectral characteristics of swelling clay minerals in the Pliocene sandstones in Xinghai, Qinghai province. XRD results show that swelling clay minerals are dominant clay minerals in the sandstones, which can be up to 97% in percentage. XRD patterns show 060 reflections of the samples occur both remarkably at 1.534 Å and 1.498 Å, indicating the samples contain physical mixtures of trioctahedral and dioctahedral swelling clay minerals, respectively. Further treatment of Li-300 degrees C heat and glycerol saturation shows the swelling clay minerals collapse to 9.3-9.9 Å with a partial expansion to -18 Å. This indicates the swelling clay minerals dominate montmorillonite and contain minor saponite. The montmorillonite shows no swelling after Li-300 degrees C heat and glycerol saturation because of Li+ inserting into the octahedral layers, which balances the layer charge caused by the substitution of Mg to Al. FTIR results show the samples are composed of a kind of phyllosilicate with absorbed and structural water, which is in agreement with the results of XRD. Absorbed peaks at 913, 842, 880 cm(-1), corresponding to OH associated with Al-Al, Al-Mg, and Al-Fe pairs, further indicates the minerals are dominant dioctahedron in structure. Meanwhile, absorbed peaks at 625 and 519 cm(-1), corresponding to coupled Si-O and Al-O-Si deformation, indicates parts of Si is replaced by Al in tetrahedron. The spectral characteristics of the samples are against the presence of beidellite and nontronite based on the results of XRD and FTIR, while demonstrating an,existence of montmorillonite. This study, to distinguish the specific species of swelling clay species in clay minerals, would be of great importance when using clay mineralogy to interpret provenance and climatic information.

  16. Flow unit modeling and fine-scale predicted permeability validation in Atokan sandstones: Norcan East Kansas

    Science.gov (United States)

    Bhattacharya, S.; Byrnes, A.P.; Watney, W.L.; Doveton, J.H.

    2008-01-01

    Characterizing the reservoir interval into flow units is an effective way to subdivide the net-pay zone into layers for reservoir simulation. Commonly used flow unit identification techniques require a reliable estimate of permeability in the net pay on a foot-by-foot basis. Most of the wells do not have cores, and the literature is replete with different kinds of correlations, transforms, and prediction methods for profiling permeability in pay. However, for robust flow unit determination, predicted permeability at noncored wells requires validation and, if necessary, refinement. This study outlines the use o f a spreadsheet-based permeability validation technique to characterize flow units in wells from the Norcan East field, Clark County, Kansas, that produce from Atokan aged fine- to very fine-grained quartzarenite sandstones interpreted to have been deposited in brackish-water, tidally dominated restricted tidal-flat, tidal-channel, tidal-bar, and estuary bay environments within a small incised-valley-fill system. The methodology outlined enables the identification of fieldwide free-water level and validates and refines predicted permeability at 0.5-ft (0.15-m) intervals by iteratively reconciling differences in water saturation calculated from wire-line log and a capillary-pressure formulation that models fine- to very fine-grained sandstone with diagenetic clay and silt or shale laminae. The effectiveness of this methodology was confirmed by successfully matching primary and secondary production histories using a flow unit-based reservoir model of the Norcan East field without permeability modifications. The methodologies discussed should prove useful for robust flow unit characterization of different kinds of reservoirs. Copyright ?? 2008. The American Association of Petroleum Geologists. All rights reserved.

  17. Sensitivity study of an image processing workflow on synchrotron μ-CT images of Berea sandstone

    Science.gov (United States)

    Leu, Leon; Berg, Steffen; Ott, Holger; Armstrong, Ryan T.; Enzmann, Frieder; Kersten, Michael

    2014-05-01

    For the present study, the sensitivity of the threshold value for watershed-based segmentation and global threshold segmentation was assessed on μ-CT images of fine grained Berea sandstone. The sensitivities were assessed in terms of porosity, permeability, single-phase flow simulations and capillary pressure curves that were calculated from the segmented data. The μ-CT images of fine grained Berea sandstone with a resolution of 3 μm/pixel was segmented using different threshold values that were systematically varied, which resulted in slightly different structures for the pore space. The results show, that watershed-based segmentation is more robust than global threshold segmentation and that the measured permeability showed a stronger sensitivity to threshold variation than porosity, indicating that it is a more sensitive parameter to image segmentation settings. Calculated permeability and capillary pressure curves matched well with experimental data revealing that the average pores and pore throats of the watershed-based segmented structure were segmented accurately. In contrast, capillary pressure curves indicated that pore sizes near the resolution limit of 3 μm, located in kaolinite rich areas of the rock, were not segmented correctly and thus caused the disagreement between the experimental measured porosity and that measured from the digital rock image. We conclude that capillary pressure curves and permeability values that result from the digital rock data is more indicative of the flow relevant fraction of the pore structure and are therefore better suited as validation criterion than porosity data. Numerical modeling of two-phase flow on segmented data from high resolution μ-CT images enhances our understanding of the dynamics of multiphase-flow of immiscible fluids at the pore-scale. To be confident about simulated data it is therefore important to identify meaningful properties, e.g. permeability, that can be used as benchmark parameters for

  18. Experimental Studies of the Effect of Permeability on Seismoelectric Conversion Coefficients in Natural and Synthetic Sandstones

    Science.gov (United States)

    Zhu, Z.; Toksoz, M. N.

    2014-12-01

    Theoretical calculation of seismoelectric conversion coefficients is difficult because it requires a large number of parameters that are hard to obtain. Much laboratory data are needed to validate the theoretical results. The most critical issue is determining independently the effect of porosity and permeability on seismoelectric coefficients. In general, when the rock porosity increases, the permeability increases too, and vice versa. In this study, we make measurements on both synthetic sandstone and two Berea (500 and 100) samples. We built a man-made "sandstone" sample with round cracks which are distributed in a horizontal plane. Thus the small cube (1.7 cm^3 ) only has one value of porosity and different permeabilities in the three directions. It is a sample with anisotropy in permeability. Laboratory experiments in a water tank show that the seismoelectric conversion coefficient is related to permeabilities in the three directions. The seismoelectric coefficient is highest in the direction of maximum permeability and lowest in the direction of minimum permeability. The measurements with the isotropic Berea samples show that seismoelectric coefficient increases with both porosity and permeability. Application of the result to borehole logging measurements requires analysis of the data from P, S, and Stoneley waves. P and Stoneley waves give large seismoelectric signals in the presence of fractures or high permeability zones. Shear waves, that do not induce fluid flow, provide very small seismoelectric signals. If the fracture strike in the formation is along the borehole axis, the P-wave induces stronger seismoelectric signal. Seismoelectric well logging might prove help for exploring the fractures or micro fractures in a borehole wall.

  19. Carbonate cementation-dissolution in deep-seated sandstones near the overpressure top in central Junggar Basin, Xinjiang, NW China

    Institute of Scientific and Technical Information of China (English)

    YANG Zhi; HE Sheng; WANG Furong; HE Zhiliang; WU Hengzhi; MENG Xianlong

    2009-01-01

    Fluid/rock interaction occurs frequently in the sandstones near the overpressure top in central Junggar Basin, and carbonate cementation-dissolution is related closely to the formation of secondary pores in the reservoir sandstones. From petrological, hydrochemical and fluid-inclusion studies of the deep-seated sandstones near the overpressure top in central Junggar Basin and the carbon and oxygen isotopic characteristics of carbonate cements in those sandstones, the following conclusions can be drawn: (1) Carbonates are the major cements. Two-stage cemen-tation was commonly developed, with late-stage ferroan carbonate cementation being dominant; several secondary porosity zones were developed vertically in the sandstones near the overpressure top, and there is a mutually com-pensatory relationship between the carbonate contents and the mean porosity; (2) the alkalescent formation-water chemical environments are in favor of carbonate precipitation; (3) there were two phases of thermal fluid activity which are related to the late-stage carbonate cementation-dissolution; (4) with the overpressure top as the boundary, carbonate cements in the sandstones have slightly negative δ13C and δ180 values, showing such a variation trend that the δ13C and δ18O values near the coal-bearing Jurassic strata are lighter, those in the overpressure top are heavier, and those at the upper part of the overpressure top are lighter, which is considered to be the result of kinetic isotope fractionation driven by episodically overpressured fluid flow; (5) carbonate cementation is closely associated with the decarboxylation of organic acids, and secondary porosity zones resultant from dissolution by organic acids and CO2 derived from Jurassic coal-beating strata, are the most important reservoir space of hydrocarbon, Studies of the mechanisms of carbonate cementation-dissolution and formation of secondary pores in the deep-seated sandstones near the overpressure top are of great

  20. Relief-induced soil zones at the Cretaceous sandstone-mudstone contact in the Stolowe Mountains, SW Poland

    Science.gov (United States)

    Kabala, Cezary; Waroszewski, Jaroslaw; Jezierski, Pawel

    2014-05-01

    Regolith translocation on mountain slope built of stratified rocks creates mixed or layered covers which may obliterate the actual transitions of rocks. The covers are seldom delineated on geological maps due to their insignificant thickness; however, enough large to influence the soil morphology and ecological functions. A toposequence of six soil sections situated at the contact of Cretaceous sandstone and mudstone was investigated to evaluate the influence of relief-position and morphological processes on slope cover formation, as well as soil and forest habitat arrangement. At least four distinct soil zones were distinguished in the 400 m long catena: (1) Arenosols and sand Regosols zone, on active fluvial cones and blocky covers directly below sandstone cliffs; (2) upper mid-slope zone of Podzols developed from sandstone-derived materials with periglacial features (solifluction) in the subsoil; (3) lower mid-slope and foot-slope zone of Stagnosols and Planosols with prolonged water stagnation over the impermeable subsoil developed from sandstone or mixed sandstone-mudstone regolith; excess of water is also the sign of mudstone bedrock that forces lateral water flow; and (4) toe-slope zone of Cambisols developed from the mudstone regolith. Past and present-day morphological processes have broadened the area mantled by sandstone-derived materials from upper-slope and created transitional materials that enhanced soil variability and multi-step zonality over the presumably sharp contact of sandstone and mudstone bedrocks. Financed in part by the Ministry of Science and Higher Education of Poland (project number: N N310 435938) and National Science Centre (project OPUS 2012/05/B/NZ9/03389). Lorz, C., Heller, K., Kleber, A. (2011): Stratification of the regolith continuum - a key property for processes and functions of landscapes. Z Geomorphol 55, 3: 277-292. Sauer, D., Felix-Heningsen, P. (2006): Saprolite, soils and sediments in the Rhenish Massif as records of

  1. Petrologic and isotopic data from the Cretaceous (Campanian) Blackhawk Formation and Star Point Sandstone (Mesaverde Group), Wasatch Plateau, Utah

    Science.gov (United States)

    Fishman, Neil S.; Turner, Christine E.; Peterson, Fred

    2013-01-01

    The presence of discrete minerals associated with coal—whether (1) detrital or authigenic constituents of the coals or in thin mudstone or siltstone units interbedded with coals, or (2) authigenic phases that formed along cleats—might influence its utilization as an energy resource. The build-up of sintered ash deposits on the surfaces of heat exchangers in coal-fired power plants, due to the alteration of minerals during combustion of the coal, can seriously affect the functioning of the boiler and enhance corrosion of combustion equipment. In particular, the presence of sodium in coals has been considered a key factor in the fouling of boilers; however, other elements (such as calcium or magnesium) and the amount of discrete minerals burned with coal can also play a significant role in the inefficiency of and damage to boilers. Previous studies of the quality of coals in the Cretaceous (Campanian) Blackhawk Formation of the Wasatch Plateau, Utah, revealed that the sodium content of the coals varied across the region. To better understand the origin and distribution of sodium in these coals, petrologic studies were undertaken within a sedimentological framework to evaluate the timing and geochemical constraints on the emplacement of sodium-bearing minerals, particularly analcime, which previously had been identified in coals in the Blackhawk Formation. Further, the study was broadened to include not just coals in the Blackhawk Formation from various localities across the Wasatch Plateau, but also sandstones interbedded with the coals as well as sandstones in the underlying Star Point Sandstone. The alteration history of the sandstones in both formations was considered a key component of this study because it records the nature and timing of fluids passing through them and the associated precipitation of sodium-bearing minerals; thus, the alteration history could place constraints on the distribution and timing of sodium mineralization in the interbedded or

  2. Optimising geological storage of CO2 by development of multiple injection sites in regionally extensive storage sandstones

    Science.gov (United States)

    Akhurst, Maxine; McDermott, Christopher; Williams, John; Mackay, Eric; Jin, Min; Tucker, Owain; Mallows, Tom; Hannis, Sarah; Pearce, Jonathan

    2016-04-01

    Carbon capture, transport and storage (CCS) is considered a key technology to provide secure, low-carbon energy supply and industrial processes to reduce the greenhouse gas emissions that contribute to the adverse effects of climatic change. Geological storage of carbon dioxide (CO2), captured during hydrocarbon production at the Sleipner Field, in strata beneath the Norwegian sector of the North Sea has been in operation since 1996. Projects to store CO2 captured at power plants in strata underlying the North Sea are currently in design. Storage of the CO2 is planned in depleted hydrocarbon fields or regionally extensive sandstones containing brine (saline aquifer sandstones). The vast majority of the UK potential storage resource is within brine-saturated sandstone formations. The sandstone formations are each hundreds to thousands of square kilometres in extent and underlie all sectors of the North Sea. The immense potential to store CO2 in these rocks can only be fully achieved by the operation of more than one injection site within each formation. Here we report an investigation into the operation of more than one injection site within a storage formation using a UK North Sea case study of the Captain Sandstone and the included Goldeneye Field, which is part of the mature hydrocarbon province offshore Scotland. Research by the CO2MultiStore project was targeted to increase understanding and confidence in the operation of two sites within the Captain Sandstone. Methods were implemented to reduce the effort and resources needed to characterise the sandstone, and increase understanding of its stability and performance during operation of more than one injection site. Generic learning was captured throughout the research relevant to the characterisation of extensive storage sandstones, management of the planned injection operations and monitoring of CO2 injection at two (or more) sites within any connected sandstone formation. The storage of CO2 can be optimised

  3. An Experimental and Numerical Study on Cracking Behavior of Brittle Sandstone Containing Two Non-coplanar Fissures Under Uniaxial Compression

    Science.gov (United States)

    Yang, Sheng-Qi; Tian, Wen-Ling; Huang, Yan-Hua; Ranjith, P. G.; Ju, Yang

    2016-04-01

    To understand the fracture mechanism in all kinds of rock engineering, it is important to investigate the fracture evolution behavior of pre-fissured rock. In this research, we conducted uniaxial compression experiments to evaluate the influence of ligament angle on the strength, deformability, and fracture coalescence behavior of rectangular prismatic specimens (80 × 160 × 30 mm) of brittle sandstone containing two non-coplanar fissures. The experimental results show that the peak strength of sandstone containing two non-coplanar fissures depends on the ligament angle, but the elastic modulus is not closely related to the ligament angle. With the increase of ligament angle, the peak strength decreased at a ligament angle of 60°, before increasing up to our maximum ligament angle of 120°. Crack initiation, propagation, and coalescence were all observed and characterized from the inner and outer tips of pre-existing non-coplanar fissures using photographic monitoring. Based on the results, the sequence of crack evolution in sandstone containing two non-coplanar fissures was analyzed in detail. In order to fully understand the crack evolution mechanism of brittle sandstone, numerical simulations using PFC2D were performed for specimens containing two non-coplanar fissures under uniaxial compression. The results are in good agreement with the experimental results. By analyzing the stress field, the crack evolution mechanism in brittle sandstone containing two non-coplanar fissures under uniaxial compression is revealed. These experimental and numerical results are expected to improve the understanding of the unstable fracture mechanism of fissured rock engineering structures.

  4. Tectonic Fractures in Tight Gas Sandstones of the Upper Triassic Xujiahe Formation in the Western Sichuan Basin,China

    Institute of Scientific and Technical Information of China (English)

    ZENG Lianbo; LI Yuegang

    2010-01-01

    The western Sichuan Basin,which is located at the front of the Longmen Mountains in the west of Sichuan Province,China,is a foreland basin formed in the Late Triassic.The Upper Triassic Xujiahe Formation is a tight gas sandstone reservoir with low porosity and ultra-low permeability,whose gas accumulation and production are controlled by well-developed fracture zones.There are mainly three types of fractures developed in the Upper Triassic tight gas sandstones,namely tectonic fractures,diagenetic fractures and overpressure-related fractures,of which high-angle tectonic fractures are the most important.The tectonic fractures can be classified into four sets,i.e.,N-S-,NE-,E-W-and NW-striking fractures.In addition,there are a number of approximately horizontal shear fractures in some of the medium-grained sandstones and grit stones nearby the thrusts or slip layers.Tectonic fractures were mainly formed at the end of the Triassic,the end of the Cretaceous and the end of the Neogene-Early Pleistocene.The development degree of tectonic fractures was controlled by lithology,thickness,structure,stress and fluid pressure.Overpressure makes not only the rock shear strength decrease,but also the stress state change from compression to tension.Thus,tensional fractures can be formed in fold-thrust belts.Tectonic fractures are mainly developed along the NE-and N-S-striking structural belts,and are the important storage space and the principal flow channels in the tight gas sandstone.The porosity of fractures here is 28.4% of the gross reservoir porosity,and the permeability of fractures being two or three grades higher than that of the matrix pores.Four sets of high-angle tectonic fractures and horizontal shear fractures formed a good network system and controlled the distribution and production of gas in the tight sandstones.

  5. Perspective and resource evaluation and metallogenic studies on sandstone-type uranium deposit in Qianjiadian depression of Songliao Basin

    International Nuclear Information System (INIS)

    The geotectonic evolution history of the southeastern part of Songliao Basin has been clearly described and it is pointed out that both of the provenance rocks and evolution features of the studied area are favorable to the formation of U-rich sandstone bodies, development of interlayered oxidation and providing uranium source for mineralization. Yaojia Formation in Qianjiadian depression has been found out to be the favorable target ore bed for looking for sandstone-type uranium deposit. On the basis of analysis of metallogenetic conditions, the perspective target area has been circled and a sandstone-type uranium deposit with a certain amounts of uranium tonnages has been discovered. The achievements and data have been gotten in the following aspects: constitution and features of ore-forming beds and sandstone bodies, uranium existence forms and mineralogical and chemical compositions of the ores, associated elements and their economic values for comprehensive mining. The study of metallogenetic features and mechanism of the uranium deposit suggested that pre-enrichment of uranium during the depositional-diagenetic stage provide a good basis for uranium mineralization, and hereafter interlayered oxidation as well as oil-gas reduction processes played a decisive role to uranium mineralization. U-Pb isotopic studies indicate that the ores have two isochron ages of 53±3 Ma and 7.0±0 Ma, corresponding to the periods of arid and semiarid paleo-climates which are favorable to interlayered oxidation development and uranium mineralization. It is concluded that the Qianjiadian sandstone-type uranium deposit is genetically related to interlayered oxidation and secondary reduction of oil-gas. The metallogenic model of Qianjiadian uranium deposit was set up. (authors)

  6. Changes in Perforation-Induced Formation Damage With Degree of Underbalance: Comparison of Sandstone and Limestone Formations

    Energy Technology Data Exchange (ETDEWEB)

    Detwiler, R; Halleck, P M; Karacan, C O; Hardesty, J

    2003-10-22

    Field data and recently developed models provide some guidance for estimating the underbalance needed to obtain fully functional perforations, but there are little data available that relate flow efficiency to lower underbalances in different rock types. To improve understanding of the surge cleanup process, we have performed two series of perforation flow tests in Berea Sandstone and in Bedford Limestone cores at increasing levels of underbalance. Flow tests were performed according to modified API RP43, section 4 test procedures. At the conclusion of the tests, the cores were analyzed using high-resolution X-ray CT techniques. The shape, dimensions and total volumes of both the open tunnel and the remaining embedded liner metal were extracted from the CT data and correlated with the underbalance and with the flow test results. Open tunnel diameters and volumes are much lower in the limestone samples. While the amount of metal remaining in the tunnel and at the perforation tip decreases dramatically with underbalance in Berea Sandstone cores, the amount of metal is nearly constant in the limestone cores. Conversely, the tunnel volume increases with underbalance in the Sandstone cores but stays constant in the limestone. Core flow efficiency results correlate with these observations. There is a sharp increase in CFE in the sandstone samples as the tunnel volumes increase and little change in CFE in the limestone samples corresponding to unchanging tunnel volume. The tests also offer some evidence of the cleanup mechanism at the perforation tip, at least in the sandstone cores. Samples at intermediate underbalance levels show evidence of open tunnel space in an annulus surrounding the metal slug at the tip. This suggests that cleanup may proceed at least partially by axial flow through crushed rock surrounding the metal. As this material erodes away, the metal is loosened and is flushed from the tunnel. Existing models for cleanup are based primarily on radial flow.

  7. 7 CFR 932.130 - Public member and alternate public member eligibility requirements and nomination procedures.

    Science.gov (United States)

    2010-01-01

    ... alternate public member. (3) A majority vote is required in Committee actions concerning the nomination of... requirements and nomination procedures. 932.130 Section 932.130 Agriculture Regulations of the Department of... member and alternate public member eligibility requirements and nomination procedures. (a)...

  8. Contribution of terrigenous rocks of South Belgian coal deposits in geological storage of CO2 : the sandstones case

    Science.gov (United States)

    Dupont, N.; Baele, J.-M.

    2009-04-01

    Sequestration of CO2 in unmined coal seams is one of the different options for storing CO2 in geological reservoirs. In favorable situations, it could be coupled with the retrieving of adsorbed methane from coal (ECBM), which can make this solution economically more attractive. However, in the case of South Belgian coal measures, both weak permeability of the coal and frequent faulting/folding of the seams are likely to decrease the efficiency of this technique. Westphalian A and B sediments from South Belgium are containing only about 2.5% vol. of coal; the other rocks consisting of shales/siltstones (~80%) and sandstones (~20%). For all these lithologies, the main processes of CO2 sequestration are 1) adsorption in coal and clay minerals that are partly forming shales, and within rock porosity in the case of sandstones and, to a lesser extent, in the shales/siltstone porosity. In a previous assessment of the sequestration potential in Westphalian coal measures of South Belgium, Baele et al. (2007) showed that coal and shales each account for 25% of the total sequestration potential, and the rest, i.e. 50%, is related to sandstones on a basis of 2% porosity. Beside their significant additional storage capacity, sandstones have also a better permeability than the other finer-grained and organic lithologies. Additionally, sandstones are known to occasionally cut the coal seams (wash-out), thus providing insights in increasing accessibility of injected CO2 into the coal. On the other hand, some sandstone banks are fossil braided rivers that induced peripheral fractures by differential compaction during burial diagenesis (Van Tongeren et al., 2000). These fractures are thus likely to have increased accessibility from high-injectivity sandstones to surrounding lithologies that could significantly contribute to storage capacity. The aim of this study is to refine the contribution of the westphalian South Belgium sandstones to the geological storage of CO2. Measurements

  9. Member states buoy up beleagured EMBL

    CERN Document Server

    Balter, M

    1999-01-01

    EMBL's governing council, made up of delegates from the lab's 16 member countries, agreed in principle to meet the costs of a multimillion-dollar pay claim, the result of a recent ruling by the ILO in Geneva (1 page).

  10. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.

    Energy Technology Data Exchange (ETDEWEB)

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-03-22

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits.

  11. What Motivates Member Donations to the Union?

    Science.gov (United States)

    Austin, James A.; Grove, Timothy L.

    2008-04-01

    In the fall of 2007, the AGU Development Board commissioned the development staff to survey the approximately 1200 AGU supporting members to learn why these members give $100 to AGU each year- many give much more-to fund activities in education, public affairs, public information, the sections, and the focus groups. (A recent list of supporting members was published in Eos, 88(49), 544-545, 2007.) With supporting membership having more than doubled since 2003, the development staff and the Development Board wanted to find out more about the individual motivations underlying this trend. We also were trying to identify new incentives for members to support the Union's special projects and programs.

  12. Israel, CERN’s new Member State

    CERN Multimedia

    Brice, Maximilien

    2014-01-01

    On Wednesday, 15 January 2014, the official Israeli Flag-raising Ceremony took place to mark the accession of Israel to Membership of CERN, bringing the Organization’s number of Member States to 21.

  13. 12 CFR 267.3 - Members.

    Science.gov (United States)

    2010-01-01

    ... persons to fill vacancies on the Council. (b) Resignation. Any member may resign at any time by giving notice to the Board. Any such resignation shall take effect upon its acceptance by the Board....

  14. 3D seismic analysis of the Collyhurst Sandstone: implications for CO2 sequestration in the East Irish Sea Basin

    Science.gov (United States)

    Gamboa, Davide; Williams, John; Kirk, Karen; Gent, Christopher; Bentham, Michelle; Fellgett, Mark; Schofield, David

    2016-04-01

    Carbon Capture and Storage (CCS) is a vital technology towards low-carbon energy resources and the mitigation of global warming trends induced by rising CO2 levels in the atmosphere. The East Irish Sea Basin (EISB) is a key area for CCS in the western UK, having high CO2 storage potentials in explored hydrocarbon fields and in saline aquifers within the Permo-Triassic Sherwood Sandstone Formation. However, the theoretical storage potential of the EISB could be poorly estimated as the reservoir-prone Lower Permian formations are not considered in detail by current estimations. This work aims to fill this gap, focusing on the characterisation of the Lower Permian Collyhurst Sandstone Formation as a viable storage unit. The potential for CO2 storage is estimated as the total volume/area of suitable closures that are isolated by structural traps, occurring at depths suitable for CO2 injection and containment (>800m). Detailed structural and stratigraphic interpretations were made using 3D seismic data to assess the storage potential of the Collyhurst Sandstone Formation in the southern EISB. The basin strata is compartmentalised by numerous N-S trending faults. A higher degree of compartmentalisation occurs within regional anticlines where elongated tilted blocks are observed, bound by predominantly west-dipping faults that induce a variable offset of the Collyhurst Sandstone strata. Contrastingly, higher lateral continuity of this formation is observed within graben basins were faults are less frequent and with minor offset, thus potentially creating larger storage closures. Fault dip orientation in the grabens is variable, with west and east dipping faults occurring as a function of large east-dipping listric faults. This study was complemented by the stress modelling of the interpreted faults in order to assess the risk of CO2 leakage. Analysis of borehole breakouts observed in four approximately vertical wells in the EISB suggest a maximum horizontal stress

  15. Petroacoustic Modelling of Heterolithic Sandstone Reservoirs: A Novel Approach to Gassmann Modelling Incorporating Sedimentological Constraints and NMR Porosity data

    Science.gov (United States)

    Matthews, S.; Lovell, M.; Davies, S. J.; Pritchard, T.; Sirju, C.; Abdelkarim, A.

    2012-12-01

    Heterolithic or 'shaly' sandstone reservoirs constitute a significant proportion of hydrocarbon resources. Petroacoustic models (a combination of petrophysics and rock physics) enhance the ability to extract reservoir properties from seismic data, providing a connection between seismic and fine-scale rock properties. By incorporating sedimentological observations these models can be better constrained and improved. Petroacoustic modelling is complicated by the unpredictable effects of clay minerals and clay-sized particles on geophysical properties. Such effects are responsible for erroneous results when models developed for "clean" reservoirs - such as Gassmann's equation (Gassmann, 1951) - are applied to heterolithic sandstone reservoirs. Gassmann's equation is arguably the most popular petroacoustic modelling technique in the hydrocarbon industry and is used to model elastic effects of changing reservoir fluid saturations. Successful implementation of Gassmann's equation requires well-constrained drained rock frame properties, which in heterolithic sandstones are heavily influenced by reservoir sedimentology, particularly clay distribution. The prevalent approach to categorising clay distribution is based on the Thomas - Stieber model (Thomas & Stieber, 1975), this approach is inconsistent with current understanding of 'shaly sand' sedimentology and omits properties such as sorting and grain size. The novel approach presented here demonstrates that characterising reservoir sedimentology constitutes an important modelling phase. As well as incorporating sedimentological constraints, this novel approach also aims to improve drained frame moduli estimates through more careful consideration of Gassmann's model assumptions and limitations. A key assumption of Gassmann's equation is a pore space in total communication with movable fluids. This assumption is often violated by conventional applications in heterolithic sandstone reservoirs where effective porosity, which

  16. Experimental determination of noble gas, SF6 and CO2 flow profiles through a porous sandstone

    Science.gov (United States)

    Kilgallon, Rachel; Gilfillan, Stuart; Edlmann, Katriona; McDermott, Chris

    2016-04-01

    The noble gases (He, Ne, Ar, Kr and Xe) and SF6 have recently been used as artificial and inherent tracers of CO2 flow and migration from within[1,2] and from geological reservoirs[3]. However, outstanding questions remain, particularly regarding the flow behaviour of the noble gases compared to CO2. Here we present results from specially constructed experimental equipment, which has been used to determine the factors affecting transport of noble gases relative to CO2 in a porous sandstone. The experimental setup consists of a sample loop that can be loaded with a desired gas mixture. This sample can be released as a pulse into a feeder gas stream through a flow cell. The flow cell consists of a 3.6 cm diameter core, which can be of any length. The sample is surrounded by aluminium foil and treated with epoxy resin inside stainless steel tubing. The flow cell is encased by two purpose designed dispersion end plates. Real-time analysis of the arrival peaks of the gases downstream is recorded using a Quadrupole Mass Spectrometer (QMS). For the experiments, a 0.96 m core of Fell Sandstone was selected to represent a porous media. Noble gases and SF6 pulses were flowed through a CO2 carrier gas at five different pressure gradients (10 - 50 kPa) with arrival profiles measured using the QMS. Surprisingly, peak arrival times of He were slower than the other noble gases at each pressure gradient. The differences in peak arrival times between He and other noble gases increased as pressure decreased and the curve profiles for each noble gas differ significantly. The heavier noble gases (Kr and Xe) along with SF6 show a steeper peak rise at initial appearance, but have a longer duration profile than the He curves. Interestingly, the breakthrough curve profiles for both Kr and Xe were similar to SF6 indicating that Kr and Xe could be substituted for SF6, which is a potent greenhouse gas, in tracing applications. In addition, CO2 pulses were passed through a N2 carrier gas. The

  17. Structural and erosive Effects of Lightning on Sandstone: An Experimental Investigation

    Science.gov (United States)

    Haddad, Houssam; Ebert, Matthias; Kenkmann, Thomas; Thoma, Klaus; Nau, Siegfried; Schäfer, Frank

    2016-04-01

    Recent prognoses predict an average temperature increase of the world's climate of about 1.5 to 2 °C until the end of 21st century. This change leads not only to a rise of the sea level but also to an increase of thunderstorms and therefore to a ~25 percent increase of cloud-to-ground lightning events (Romps et al., 2014). It is known that (i) lightning strikes are able to fragment surface rocks, which probably influences the erosion rates at exposed mountain areas (Knight and Grab, 2014), and (ii) the efficiency of the process increases due to the predicted climate change. However, our knowledge about the electro-mechanical destruction of rocks caused by high energetic lightning is incomplete. In this study, laboratory experiments of lightning strikes were performed in order to understand the fragmentation of rocks and changes to landforms by lightning. The artificial lightning with known electric current was simulated by a high-current generator in the laboratories of the Fraunhofer Ernst-Mach Institute for High-Speed Dynamics (Freiburg, Germany). Different currents were transferred over a distance of ~2mm onto water-saturated sandstones by using a copper cathode (3 experiments; U, I, E, Δt: 6 kV, 200 kA, 0.1 MJ, 0.7 ms; 9 kV, 300 kA, 0.19 MJ, 0.9 ms; 12 kV, 400 kA, 0.35 MJ, 0.5 ms). The damaged sandstones were investigated by means of optical and electron-optical methods as well as by X-ray computed tomography to determine the modes and dimensions of melting and fragmentation. Digital elevation models of craters formed by ejection were obtained by white-light interferometry. The lightning experiments produced small craters (~1 cm in diameter, ~0.5 cm depth) which surfaces and sub-surfaces consist of silicate melts (molten quartz and phyllosilicates). The silicate melts reach several hundred micrometers into the sub-surface and resemble the appearance of natural fulgurites. Melting of quartz indicate temperatures of at least 1650 °C. In addition, the

  18. Petrophysical properties and 3D block model of Buntsandstein Sandstones reservoir (Upper Rhine Graben)

    Science.gov (United States)

    Sébastien, Haffen; Yves, Géraud; Marc, Diraison; Chrystel, Dezayes

    2013-04-01

    Buntsandstein sandstones (upper Permian to middle Triassic), located in the Upper Rhine Graben, appear as an easy target for geothermal exploitation: this reservoir links more or less permeable argillaceous sandstones, intersected by many major faults, to the regional thermal anomaly. In this context, we propose a conceptual geological 3-D block model of the Buntsandstein reservoir which could be used as a guide for future regional geothermal exploration or exploitation. This block presents the Buntsandstein sandstones reservoir at depth with different sedimentary facies (braided rivers, playa lake and fluvio-aeolian), above the Palaeozoic Granit and below the Muschelkalk limestones, intersecting by faults oriented according regional major azimuths: (1) ≈N020°E, corresponding to Rhenish faults and (2) ≈N060°E (or ≈N130°E) corresponding to Hercynian reactivated faults. Petrophysical properties of the reservoir are both controlled by matrix and faults/fractures characteristics. (1) Matrix properties (porosity, permeability, thermal conductivity, Pwaves velocity) have been determined from petrophysical measurements performed on cores of 15 borehole, mainly on borehole EPS1 (Soultz-sous-Forêts, France), continuously cored through Buntsandstein; (2) from thermal gradient analyses based on thermal conductivity measurements on core samples and also from borehole temperature logs run in the same borehole. This last approach allows locating fluid flow and thus permeability at reservoir scale. The flow paths appear as a composite network controlled by 'sedimentary' permeability on one hand and by 'fracture' permeability on the other. Fracturing associated with major fault zones provide pathways for the upward flowing fluids to connect with stratigraphic levels characterized by high matrix permeability and no impermeable macroscopic layers. This is why the Playa Lake and Fluvio-aeolian marginal erg facies provide a reservoir connected to a deep hot fluid source

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-02-01

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

  20. Control On Fluid Flow Properties In Sandstone: Interactions Between Diagenesis Processes And Fracture Corridors

    Science.gov (United States)

    Bossennec, Claire; Géraud, Yves; Moretti, Isabelle; Mattioni, Luca

    2016-04-01

    During the development of a fault zone, processes occur at different scales: secondary faults and fractures development in the damage zone while "diagenetic" processes, i.e: fluid rock interaction at the grains size scale, contribute to modify the matrix features. Spatial distribution of these processes is clearly controlled by microstructural transformations induced by fractured corridors and their location. Understanding flowing properties in the associated damage zone contributes to the better modeling of the fluid flow in faulted and fractured reservoirs which could be oil, gas or water bearing. The Lower Triassic Buntsandstein sandstones outcrop of Cleebourg is located in the Hochwald Horst affected by a major NNE-SSW striking fault, and the structure globally dips with 30° toward Rhenish Fault (Upper Rhine Graben main western border fault). The study of the outcrop aims to decipher the fluid-flow scheme and interactions between fracture network and diagenetic features distribution in the damage zone of a fault, located close to major faulted areas, through field and laboratories petrophysical measurements (permeability, thermic conductivity), and samples microstructural and diagenetical descriptions. The outcrop is structurally divided into a 14 meters thick fault core, surrounded by 5 meters thick transition zones, and damage zone of minimum thickness of 40 meters (total thickness unknown, due to the limits of the outcrop). Damage zone includes three fractured corridors, perpendicular to bedding and from 2 to 5 meters thick. Results presented here were acquired in 2 different layers with similar lithology but only on damage zone samples. In entire damage zone, porosity results and thin section description allow to distinguish two different facies: • Fa1 Intermediate porous (porosity of 12%) sandstone with major illite cement and clay content up to 20% (detrital and diagenetic); • Fa2 High porous (porosity >15%) sandstone with quartz feeding

  1. Source and characteristic of salinity in the Nubian sandstone aquifer (Khartoum State)

    International Nuclear Information System (INIS)

    The study area is bounded by latitudes 15.20 N-15.92 N (1680000-1760000 UTM) and longitudes 32.34 E-32.72 E (430000-470000 UTM). It occupies an area of 2400 km within the Khartoum State. Khartoum State represents 1% of the total surface area of the Sudan. The capital of the State is composed of the three towns Khartoum, Omdurman and Bahri. The geological formations were found to be composed of Gezira and the Nubian sandstone, Groundwater occurs in these two formations. This study investigated the source of salinity and the quality of ground water in the Nubian sandstone aquifer in the Khartoum State. The principal objective of the study is to detect possible sources of salinity that have affected the ground water in the study area. Uni variant and multi variant statistical methods together with graphical techniques using aqua chem and excel soft ware were employed to study the hydrochemistry of the brackish water zone of the Khartoum State. This study has revealed the following conclusions: The least total dissolved soils (TDS) occur in the Khartoum area (1024 ppm). but the study area of Bahri and Shareg Elneil has the highest total dissolved soils (2391 ppm). The concentration of the calcium (Ca) and the bicarbonate (HCO3) is fairly homogeneous in all the study area and there is no much variation. The content of magnesium (Mg) is slightly lower than calcium in the three studied areas. The main concentration value of chloride ion, (178 ppm) is slightly higher in Bahri than in the other two ares, Omdurman, Khartoum which have values of 144 ppm, 150 ppm, respectively. The higher concentration of nitrate (NO3) in the groundwater of Bahri area indicates that there is a significant source of pollution in this area. From factor analysis the effective component which contributes 48% of the total variants is composed of (sodium Na, magnesium Mg, chlorite Cl, sulphate SO4, and nitrate NO3) which contribute significantly to the mineralization of the groundwater in the study

  2. Diagenesis of Oligocene continental sandstones in salt-walled mini-basins-Sivas Basin, Turkey

    Science.gov (United States)

    Pichat, Alexandre; Hoareau, Guilhem; Callot, Jean-Paul; Ringenbach, Jean-Claude

    2016-06-01

    The recent discovery of Oligo-Miocene salt-walled continental mini-basins in the Sivas Basin (central Anatolia, Turkey) provides the opportunity to unravel the influence of halokinesis on the diagenesis of continental mini-basin infilling. In this study, petrographic and geochemical analyses are used to define the diagenetic sequences recorded by two mini-basins filled mainly by fluvial clastic sediments of the upper Oligocene Karayün Formation. The initial diagenetic features are those commonly encountered in arid to semi-arid continental environments, i.e. clay infiltration, hematite precipitation and vadose calcite cement. Other early cements were strongly controlled by sandstone detrital composition in the presence of saline/alkaline pore water. In feldspathic litharenites and lithic arkoses, near-surface alterations were characterized by the precipitation of analcime (up to 10%), albite and quartz overgrowths (< 1%). These events were followed by extensive calcite cementation (up to 30%) during shallow burial diagenesis which prevented further mesogenetic alteration phenomena such as compaction. In feldsarenites, early diagenesis differs by (i) the absence of analcime, (ii) better developed albite cements, (iii) thin smectite-illite coatings forming pore linings and (iv) patchy calcite cementation (< 5%). The limited development of calcite cement allowed mesogenetic alterations to occur, such as late quartz overgrowths, albitization of feldspar grains and chemical compaction. All these phases are responsible for the low porosity of feldsarenites (< 2%). The greater abundance of carbonate cement in feldspathic litharenites and lithic arkoses is related to a greater proportion of detrital limestone in these sandstones. Early precipitation of analcime, albite, smectite-illite and quartz was likely triggered by the alteration of reactive grains by near-surface saline/alkaline brines originating from the dissolution of adjacent diapiric structures. Mini

  3. Petrophysical characterization of three commercial varieties of miocene sandstones from the Ebro valley

    Directory of Open Access Journals (Sweden)

    Gisbert, J.

    2007-08-01

    Full Text Available Miocene sandstones studied were used extensively to build Aragon’s architectural heritage, are still used in modern construction. The quarries presently located on the edge of the Ebro Valley depression. The present paper describes an exhaustive petrophysical study of these materials, which while, of the same age and from the same deposition basin, exhibit different mineralogical and textural characteristics and as a result, different physical and mechanical properties and durability. The petrographic and petrophysical characteristics of these materials were evaluated with tests prescribed in UNE (Spanish, NORMAL and ASTM standards. All the results were subjected to statistical analysis to identify possible textural and compositional nonuniformities in the material that may underlie behavioural changes. The results of the present paper show that their petrophysical characteristics afford these sandstones substantial industrial value as construction materials. Durability was found to be longest in the Alcañiz stone, as a result of the geometry of its pore network.Las areniscas miocenas estudiadas han sido y son ampliamente utilizadas en patrimonio histórico y en obra civil moderna, localizándose las canteras actuales en el borde de la depresión del Ebro. Se ha realizado un exhaustivo estudio de las características petrofísicas de estos materiales, que pese a presentar la misma edad y pertenecer a la misma cuenca sedimentaria presentan características mineralógicas y texturales diferentes que les confieren diferentes propiedades físicas, mecánicas y una diferente durabilidad. Las características petrográficas y petrofísicas se han evaluado mediante la realización de ensayos según las normas UNE, NORMAL y ASTM. Para todos los ensayos se ha realizado un tratamiento estadístico de los resultados para evaluar las posibles inhomogeneidades texturales y composicionales presentes en el material y que pueden originar modificaciones en

  4. Energy monitoring and analysis during deformation of bedded-sandstone: use of acoustic emission.

    Science.gov (United States)

    Wasantha, P L P; Ranjith, P G; Shao, S S

    2014-01-01

    This paper investigates the mechanical behaviour and energy releasing characteristics of bedded-sandstone with bedding layers in different orientations, under uniaxial compression. Cylindrical sandstone specimens (54 mm diameter and 108 mm height) with bedding layers inclined at angles of 10°, 20°, 35°, 55°, and 83° to the minor principal stress direction, were produced to perform a series of Uniaxial Compressive Strength (UCS) tests. One of the two identical sample sets was fully-saturated with water before testing and the other set was tested under dry conditions. An acoustic emission system was employed in all the testing to monitor the acoustic energy release during the whole deformation process of specimens. From the test results, the critical joint orientation was observed as 55° for both dry and saturated samples and the peak-strength losses due to water were 15.56%, 20.06%, 13.5%, 13.2%, and 13.52% for the bedding orientations 10°, 20°, 35°, 55°, and 83°, respectively. The failure mechanisms for the specimens with bedding layers in 10°, 20° orientations showed splitting type failure, while the specimens with bedding layers in 55°, 83° orientations were failed by sliding along a weaker bedding layer. The failure mechanism for the specimens with bedding layers in 35° orientation showed a mixed failure mode of both splitting and sliding types. Analysis of the acoustic energy, captured from the acoustic emission detection system, revealed that the acoustic energy release is considerably higher in dry specimens than that of the saturated specimens at any bedding orientation. In addition, higher energy release was observed for specimens with bedding layers oriented in shallow angles (which were undergoing splitting type failures), whereas specimens with steeply oriented bedding layers (which were undergoing sliding type failures) showed a comparatively less energy release under both dry and saturated conditions. Moreover, a considerable amount of

  5. Degradation processes and consolidation of Late Jurassic sandstone dinosaur tracks in museum environment (Museum of Lourinhã, Portugal)

    Science.gov (United States)

    Leal, Sofia; mateus, Octavio; Tomas, Carla; Dionisio, Amelia

    2014-05-01

    The current study aims to conciliate conservation and restoration museology diagnosis with paleontological and geological curational needs and has, as subject of study, dinosaur footprints (vertebrates fossils). The footprints have been being exposed since 2004 in the paleontology hall of the Museum of Lourinhã, Portugal, and are part of a important paleontological collection of Late Jurassic vertebrate fossils from Lourinhã Formation. Presently, it is considered a unique heritage in danger of disappearing due to high decay level of disaggregation of its geological structure. The dinosaur footprints, (ML557) found, more precisely, on a coastline cliff in Lourinhã, Porto das Barcas, Lagido do Forno (coordinate 39° 14. 178'N, 9° 20. 397'W), Jurassic period, on the 5th of June 2001, by Jesper Milàn. This cliff of high slope presents sedimentary stratigraphic characteristics of a sandstone/siltstone of gray and red colors, by the '' Munsell scale and Color Chart''. Geological the tracks are Late Jurassic in age, and colected in the Lourinhã Formation, Praia Azul Member, of the Lusitanian Basin. There are three natural infills tridactyl tracks, possibly ascribed to ornithopod, a bipedal herbivore, resultant of a left foot movement, right and left. Footprints have 300-400mm of wide and 330-360mm of height with round fingers, which are elongated due to some degradation/erosion. In 2001, the footprints were collected from the field, cleaned, consolidated and glued in the laboratory of the Museum of Lourinhã before being exhibited in a museum display. Stone matrix was removed and a consolidation product applied, probably a polyvinyl acetate, of the brand Plexigum. The footprint with broken central digit was glued with an epoxy resin, Araldite. Both applied products were confirmed by analysis of µ-FTIR (Fourier Transform Infrared Spectroscopy) and both presented colour change and detachment surface problems. After collecting and storing, in 2004, footprints were

  6. The dangers of taking mud for granted: Lessons from Lower Old Red Sandstone dryland river systems of South Wales

    Science.gov (United States)

    Wright, V. Paul; Marriott, Susan B.

    2007-02-01

    Mudrocks are a prominent feature of many ancient dryland successions but they are not always a product of the settling out of suspension load. From studies of the late Silurian-early Devonian Old Red Sandstone mudrocks of South Wales it has been shown that many were not overbank sediments deposited from suspension on floodplains, but were emplaced as sand- and silt-sized aggregates transported as bed load and deposited in sinuous channels and as braid-bar complexes on multi-stage floodplains in dryland river systems. Using the Old Red Sandstone examples criteria are provided for the recognition of similar deposits in the sedimentary record. One important aspect of these mudrocks is that they can represent multiple recycling events and can constitute condensed deposits that may be characteristic of closed alluvial basins with periodically limited sediment supply.

  7. Studies on methods and techniques of weak information extraction and integrated evaluation for sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Weak information extraction and integrated evaluation for sandstone-type uranium deposits are currently one of the important research contents in uranium exploration. Through several years researches, the authors put forward the meaning of aeromagnetic and aeroradioactive weak information extraction, study the formation theories of aeromagnetic and aeroradioactive weak information and establish effective mathematic models for weak information extraction. Based on GIS software, models of weak information extraction are actualized and the expert-grading model for integrated evaluation is developed. The trial of aeromagnetic and aeroradioactive weak information and integrated evaluation of uranium resources are completed by using GIS software in the study area. The researchful results prove that techniques of weak information extraction and integrated evaluation may further delineate the prospective areas of sandstone-type uranium deposits rapidly and improve the predicitive precision. (authors)

  8. Development of GIS based data processing system for regional geophysical and geochemical exploration of sandstone-hosted uranium deposits

    International Nuclear Information System (INIS)

    According to the exploration and evaluation need of sandstone-hosted uranium deposits, the function design of data processing system for the regional geophysical and geochemical exploration has been completed in the paper. The development technique route of the system software and key technique about mixed programming are introduced, and the geophysical and geochemical data processing software with powerful functions has been also developed which remedies the shortage of GIS software for extracting the metallogenic information for uranium deposits. The development process of system software is introduced in detail through some development examples. Application practices disclose that the interface of developed system software with friendly interface and practical functions, may quickly fulfill the data processing of regional geophysical and geochemical exploration and provide the helpful deep information for predicting metallogenic prospective areas of sandstone-hosted uranium deposits. (authors)

  9. Study on methods and techniques of aeroradiometric weak information extraction for sandstone-hosted uranium deposits based on GIS

    International Nuclear Information System (INIS)

    The weak information extraction is one of the important research contents in the current sandstone-type uranium prospecting in China. This paper introduces the connotation of aeroradiometric weak information extraction, and discusses the formation theories of aeroradiometric weak information extraction, and discusses the formation theories of aeroradiometric weak information and establishes some effective mathematic models for weak information extraction. Models for weak information extraction are realized based on GIS software platform. Application tests of weak information extraction are realized based on GIS software platform. Application tests of weak information extraction are completed in known uranium mineralized areas. Research results prove that the prospective areas of sandstone-type uranium deposits can be rapidly delineated by extracting aeroradiometric weak information. (authors)

  10. Nuclear Magnetic Resonance Measurements of Original Water Saturation and Mobile Water Saturation in Low Permeability Sandstone Gas

    Institute of Scientific and Technical Information of China (English)

    GAO Shu-Sheng; YE Li-You; XIONG Wei; GUO He-Kun; HU Zhi-Ming

    2010-01-01

    @@ We use nuclear magnetic resonance(NMR)and centrifugation to measure the original water saturation and mobile water saturation of cores from the Xujiahe low permeability sandstone gas reservoir,and compare the NMR results with the corresponding field data.It is shown that the NMR water saturation after 300 psi centrifugation effectively represents the original water saturation measured by weighing fresh cores.There is a good correlation between mobile water saturation and the water production performance of the corresponding gas wells.The critical mobile water saturation whether reservoir produces water of the Xujiahe low permeability sandstone gas is 6%.The higher the mobile water saturation,the greater the water production rate of gas well.This indicates that well's water production performance can be forecasted by mobile water saturation of cores.

  11. Effect of tomography resolution on the calculated microscopic properties of porous materials: Comparison of sandstone and carbonate rocks

    Science.gov (United States)

    Gooya, R.; Bruns, S.; Müter, D.; Moaddel, A.; Harti, R. P.; Stipp, S. L. S.; Sørensen, H. O.

    2016-09-01

    X-ray computed tomography is useful for providing insight into the internal structure of porous materials. Extracting reliable quantitative information is difficult because the derived properties rely heavily on data resolution, i.e., very different values emerge, depending on the relationship between size of the features in the sample and the resolution of the 3D tomograms. Here, we present a method for testing if resolution is sufficient for determining reliable petrophysical parameters, i.e., with low levels of uncertainty. We derived the physical properties of sandstone and carbonate rocks over a range of voxel dimensions by computationally reducing raw data resolution in our high resolution images. Lower resolution decreases the calculated surface area for all samples and increases the derived permeability for sandstone. The permeability vs change in resolution was not monotonic for carbonates. The differences in trends for the two rock types result from different pore sizes and pore size distributions.

  12. Permeability Heterogeneity in a Fractured Sandstone-Mudstone Rock Mass in Xiaolangdi Dam Site, Central China

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiaowei; WAN Li; WANG Xusheng; KANG Aibin; HUANG Jun; HUANG Guoxing

    2009-01-01

    Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology.Numerous approaches have been proposed to characterize heterogeneity in the last several decades.However, little attention has been paid to correlate permeability heterogeneity with geological information. In the present study, several causes of permeability heterogeneity, that is, lithology,tectonism, and depth, are identified. The unit absorption values (denoted as ω), which are results obtained from the packer test, are employed to represent permeability. The variability of permeability in sandstone-mudstone is so significant that the value of unit absorptions span 3-4 orders of magnitude at any depth with several test sections. By declustering, it has been found that under a similar tectonic history, the means of permeability differ greatly at different formations as a result of different mudrock contents. It has also been found that in the same formation, permeability can he significantly increased as a result of faulting. The well-known phenomenon, the decrease in permeability with depth, is found to be caused by the fractures in the rock mass, and the relationship between permeability and depth can be established in the form of logω-logd. After subtracting the trend of ω with absolute depth, the mean of the residual value at each relative depth can be well correlated with the distribution of mudstone.The methods proposed in this paper can be utilized to research in similar study areas.

  13. Basical characteristics of fluid geologic process of interlayer oxidation zone sandstone-typeuranium deposit

    Institute of Scientific and Technical Information of China (English)

    WU; BoLin; LIU; ChiYang; WANG; JianQiang

    2007-01-01

    This paper reveals the physicochemical properties such as component, formulation, genesis, tem- perature, pH, Eh, salinity and pressure of all main alteration fluid of interlayer oxidation zone sand- stone-type uranium deposits after studying the geologic process and geochemistry of internal typical sandstone-type uranium deposits such as Shihongtan deposit in the Turpan-Hami basin, 512 deposit in the Yili basin, Dongsheng deposit in the Ordos basin. The composition of fluid can be divided into two parts based on the analysis of inclusion: one can be affirmed as atmospheric water with ordinary temperature epigenesist according to the character of hydrogen and oxygen isotope of inclusion, the other is natural gas containing gaseous hydrocarbon like CH4, and CO2 as well as a little H2S, CO, H2, N2 and so on, it always contains a small quantity of hydrocarbon liquid in petroliferous basins. The fluid property of oxidation alteration zone is always oxidation alkaline, and neutrality or weak acid-weak alkaline and reducibility during the metallizing process, but at secondary reduction or deoxidization zone it becomes strong reduction alkaline. Oxygenic groundwater in the fluid is the activate and mig- ratory medium of uranium element, but the gaseous hydrocarbon like CH4 as well as H2, H2S, CO from natural gas is the important sedimentary reducer of uranium mineral; the transformation of pH,Eh in fluid environment is the main reason for the formation of uranium metallization.

  14. Diagenetic Evolution and Reservoir Quality of Sandstones in the North Alpine Foreland Basin: A Microscale Approach.

    Science.gov (United States)

    Gross, Doris; Grundtner, Marie-Louise; Misch, David; Riedl, Martin; Sachsenhofer, Reinhard F; Scheucher, Lorenz

    2015-10-01

    Siliciclastic reservoir rocks of the North Alpine Foreland Basin were studied focusing on investigations of pore fillings. Conventional oil and gas production requires certain thresholds of porosity and permeability. These parameters are controlled by the size and shape of grains and diagenetic processes like compaction, dissolution, and precipitation of mineral phases. In an attempt to estimate the impact of these factors, conventional microscopy, high resolution scanning electron microscopy, and wavelength dispersive element mapping were applied. Rock types were established accordingly, considering Poro/Perm data. Reservoir properties in shallow marine Cenomanian sandstones are mainly controlled by the degree of diagenetic calcite precipitation, Turonian rocks are characterized by reduced permeability, even for weakly cemented layers, due to higher matrix content as a result of lower depositional energy. Eocene subarkoses tend to be coarse-grained with minor matrix content as a result of their fluvio-deltaic and coastal deposition. Reservoir quality is therefore controlled by diagenetic clay and minor calcite cementation.Although Eocene rocks are often matrix free, occasionally a clay mineral matrix may be present and influence cementation of pores during early diagenesis. Oligo-/Miocene deep marine rocks exhibit excellent quality in cases when early cement is dissolved and not replaced by secondary calcite, mainly bound to the gas-water contact within hydrocarbon reservoirs. PMID:26365327

  15. Modeling the nonlinear hysteretic response in DAE experiments of Berea sandstone: A case-study

    Energy Technology Data Exchange (ETDEWEB)

    Pecorari, Claudio, E-mail: claudio.pecorari@hotmail.com [Hesjakollen 111 A, 5142 Bergen (Norway)

    2015-03-31

    Dynamic acousto-elasticity (DAE) allows probing the instantaneous state of a material while the latter slowly and periodically is changed by an external, dynamic source. In DAE investigations of geo-materials, hysteresis of the material's modulus defect displays intriguing features which have not yet been interpreted in terms of any specific mechanism occurring at atomic or mesoscale. Here, experimental results on dry Berea sandstone, which is the rock type best investigated by means of a DAE technique, are analyzed in terms of three rheological models providing simplified representations of mechanisms involving dislocations interacting with point defects which are distributed along the dislocations' core or glide planes, and microcracks with finite stiffness in compression. Constitutive relations linking macroscopic strain and stress are derived. From the latter, the modulus defect associated to each mechanism is recovered. These models are employed to construct a composite one which is capable of reproducing several of the main features observed in the experimental data. The limitations of the present approach and, possibly, of the current implementation of DAE are discussed.

  16. Geology and recognition criteria for roll-type uranium deposits in continental sandstones. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Harshman, E.N.; Adams, S.S.

    1981-01-01

    The study of roll-type deposits during the past 20 years, since the first description of a deposit in the United States, has developed general concepts of ore formation which are accepted widely and are compatible with available data. If this were not the case the concepts would not have endured and could not have been so successfully applied to exploration using the relations of altered-unaltered sandstone. The comparative simplicity of the model, and the ease with which it has been applied to exploration have, oddly enough, probably inhibited detailed studies of ore districts that would have provided data now needed for refinement of ore controls for exploration and resource assessment programs. The most thorough study of a roll-type district was that of the Shirley Basin which is drawn on heavily in this report. The general concept of roll-type formation provides a strong basis for the development of geological observations and guides, or recognition criteria, for resource studies and exploration. Indeed, industry has been developing and using them for 20 years. As the objective of this study was to identify the most useful recognition criteria and develop a method for their systematic use in resource studies and exploration, the study is best summarized by reference to the important geological observations about roll-type deposits.

  17. Geology and recognition criteria for roll-type uranium deposits in continental sandstones. Final report

    International Nuclear Information System (INIS)

    The study of roll-type deposits during the past 20 years, since the first description of a deposit in the United States, has developed general concepts of ore formation which are accepted widely and are compatible with available data. If this were not the case the concepts would not have endured and could not have been so successfully applied to exploration using the relations of altered-unaltered sandstone. The comparative simplicity of the model, and the ease with which it has been applied to exploration have, oddly enough, probably inhibited detailed studies of ore districts that would have provided data now needed for refinement of ore controls for exploration and resource assessment programs. The most thorough study of a roll-type district was that of the Shirley Basin which is drawn on heavily in this report. The general concept of roll-type formation provides a strong basis for the development of geological observations and guides, or recognition criteria, for resource studies and exploration. Indeed, industry has been developing and using them for 20 years. As the objective of this study was to identify the most useful recognition criteria and develop a method for their systematic use in resource studies and exploration, the study is best summarized by reference to the important geological observations about roll-type deposits

  18. The use of point load test for Dubai weak calcareous sandstones

    Institute of Scientific and Technical Information of China (English)

    Amr Farouk Elhakim

    2015-01-01

    Intact rock is typically described according to its uniaxial compressive strength (UCS). The UCS is needed in the design of geotechnical engineering problems including stability of rock slopes and design of shallow and deep foundations resting on and/or in rocks. Accordingly, a correct measure-ment/evaluation of the UCS is essential to a safe and economic design. Typically, the UCS is measured using the unconfined compression tests performed on cylindrical intact specimens with a minimum length to width ratio of 2. In several cases, especially for weak and very weak rocks, it is not possible to extract intact specimens with the needed minimum dimensions. Thus, alternative tests (e.g. point load test, Schmidt hammer) are used to measure rock strength. The UCS is computed based on the results of these tests through empirical correlations. The literature includes a plethora of these correlations that vary widely in estimating rock strength. Thus, it is paramount to validate these correlations to check their suitability for estimating rock strength for a specific location and geology. A review of the available correlations used to estimate the UCS from the point load test results is performed and summarized herein. Results of UCS, point load strength index and Young’s modulus are gathered for calcareous sandstone specimens extracted from the Dubai area. A correlation for estimating the UCS from the point load strength index is proposed. Furthermore, the Young’s modulus is correlated to the UCS.

  19. The use of point load test for Dubai weak calcareous sandstones

    Directory of Open Access Journals (Sweden)

    Amr Farouk Elhakim

    2015-08-01

    Full Text Available Intact rock is typically described according to its uniaxial compressive strength (UCS. The UCS is needed in the design of geotechnical engineering problems including stability of rock slopes and design of shallow and deep foundations resting on and/or in rocks. Accordingly, a correct measurement/evaluation of the UCS is essential to a safe and economic design. Typically, the UCS is measured using the unconfined compression tests performed on cylindrical intact specimens with a minimum length to width ratio of 2. In several cases, especially for weak and very weak rocks, it is not possible to extract intact specimens with the needed minimum dimensions. Thus, alternative tests (e.g. point load test, Schmidt hammer are used to measure rock strength. The UCS is computed based on the results of these tests through empirical correlations. The literature includes a plethora of these correlations that vary widely in estimating rock strength. Thus, it is paramount to validate these correlations to check their suitability for estimating rock strength for a specific location and geology. A review of the available correlations used to estimate the UCS from the point load test results is performed and summarized herein. Results of UCS, point load strength index and Young's modulus are gathered for calcareous sandstone specimens extracted from the Dubai area. A correlation for estimating the UCS from the point load strength index is proposed. Furthermore, the Young's modulus is correlated to the UCS.

  20. Dictyonema black shale and Triassic sandstones as potential sources of uranium

    Directory of Open Access Journals (Sweden)

    Kiegiel Katarzyna

    2015-09-01

    Full Text Available The main objective of the present study was an assessment of the possibility of uranium recovery from domestic resources in Poland. In the first stage uranium was leached from the ground uranium ore by using acidic (sulfuric acid or hydrochloric acid or alkaline (carbonate solutions. The leaching efficiencies of uranium were dependent on the type of ore and it reached 81% for Dictyonemic shales and almost 100% for sandstones. The novel leaching routes, with the application of the helical membrane contactor equipped with rotating part were tested. The obtained postleaching solutions were concentrated and purified using solvent extraction or ion exchange chromatography. New methods of solvent extraction, as well as hybrid processes for separation and purification of the product, were studied. Extraction with the use of membrane capillary contactors that has many advantages above conventional methods was also proposed as an alternative purification method. The final product U3O8 could be obtained by the precipitation of ‘yellow cake’, followed by calcination step. The results of precipitation of ammonium diuranate and uranium peroxide from diluted uranium solution were presented