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Sample records for ahwaz sandstone member

  1. Fluvial sedimentology of a major uranium-bearing sandstone - A study of the Westwater Canyon member of the Morrison Formation, San Juan Basin, New Mexico

    International Nuclear Information System (INIS)

    The Westwater Canyon Member of the Morrison Formation, the main ore-bearing sandstone in the San Juan basin, consists of a sequence of vertically stacked braided stream deposits. Three fluvial units within the sequence can be delineated in the basin. Volcanic pebbles are abundant in the middle fluvial unit, in a zone that forms a crude time line. A pronounced thickening of sandstone in the Westwater Canyon Member north of Gallup, once believed to be the apex of a large alluvial fan, is now thought to merely reflect a greater accumulation of sediment in response to downwarping of the basin in that area. Provenance studies suggest that highlands that contributed detritus to Westwater Canyon streams were located several hundred kilometers to the west and southwest of the San Juan basin, and thus fan apices would also have been several hundred kilometers upstream. The fluvial units recognized in the basin may well be coalesced distal fan deposits, but are probably best interpreted as vertically stacked braided steam sequences. Facies changes in fine-grained interbeds of the Westwater Canyon probably have greater significance in terms of localizing ore than any special attribute of the fluvial sandstones themselves. Uranium ore generally occurs in sandstones that are interbedded with greenish-gray lacustrine mudstones. Pore waters that were expelled from these mudstones are thought to have been the source of the pore-filling organic matter (humate) associated with primary uranium ore in nearby sandstones

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

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    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.

  3. A new method for recovering paleoporosity of sandstone: case study of middle Es3 member of Paleogene formation in Niuzhuang Sag, Dongying Depression, Bohai Bay Basin in China

    Science.gov (United States)

    Liu, Mingjie; Liu, Zhen; Wang, Biao; Sun, Xiaoming; Guo, Jigang

    2015-09-01

    This paper presents a new method for recovering paleoporosity of sandstone reservoirs and quantitatively defines the evolution process of porosity. This method is based on the principle that the present is the key to the past. We take the middle Es3 member in Niuzhuang Sag, Dongying Depression, and Bohai Bay Basin as an example. The method used in this study considers the present porosity as a constraint condition, and the influences of both constructive diagenesis and destructive diagenesis to divide the porosity evolution process into two independent processes, namely porosity increase and porosity decrease. An evolution model of sandstone porosity can be established by combining both the pore increase and pore decrease effects. Our study reveals that the porosity decrease model is a continuous function of burial depth and burial time, whereas the porosity increase model mainly occurs in an acidified window for paleotemperature of 70°C to 90°C. The porosity evolution process can be divided into the following phases: normal compaction, acidification and pore increase, and post-acidification compaction. Thus, the porosity evolution model becomes a piecewise function of three subsections. Examples show that the method can be applied effectively in recovering the paleoporosity of sandstone reservoirs and simulating the porosity evolution process.

  4. 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...

  5. Public Attitudes Toward Cadaveric Organ Donation: a Survey in Ahwaz

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    Maryam Barfi

    2006-02-01

    -para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;}

    Introduction: The aim of this study was to evaluate the attitudes of the residents of Ahwaz toward organ donation after brain death.

    Materials and Methods: A total of 1000 people between 15 and 70 years of age were selected by cluster sampling in Ahwaz, south-west of Iran. A questionnaire was designed about the attitudes of the interviewees toward organ donation after brain death by themselves and by their family members, demanding compensation for organ donation, and the need for consent or testimony.

    Results: Of the participants, 75% were pro organ donation, while 22% were against it and the remaining 3% had no specific idea. Age, sex, and occupation did not influence the attitudes; however, the ethnicity, educational level, economic status, and having a loved one in need of organ transplantation significantly increased the willingness of these people for organ donation (P < .05. Regarding the issue of demanding compensation for organ donation, 27% of the participants were in favor of the idea and 73% disagreed. A higher proportion of the participants with higher educational levels believed in organ donation without any consent or testimony (P = .02.

    Conclusion:
  6. 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)

  7. Adenomyosis among samples from hysterectomy due to abnormal uterine bleeding in Ahwaz, southern Iran

    OpenAIRE

    Maryam Dehghani Mobarakeh; Ahmadreza Maghsudi; Iran Rashidi

    2012-01-01

    Introduction: Adenomyosis is one of the most common, yet underdiagnosed, underlying causes of abnormal uterine bleeding (AUB). We aimed to evaluate the prevalence of adenomyosis among subjects who underwent hysterectomy due to AUB. Materials and Methods: We studied the pathological specimens from 100 cases of AUB who underwent hysterectomy and were referred to Jundishapur University of Medical Sciences, Ahwaz (Iran) from 2007 to 2010. All specimens were reviewed by the same pathologist. ...

  8. Permeability anisotropy and heterogeneity of a sandstone reservoir analogue : an estuarine to shoreface depositional system in the Virgelle Member, Milk River Formation, Writing-on-Stone Provincial Park, southern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, R. [Memorial Univ. of Newfoundland, St. John' s, NL (Canada). Dept. of Earth Sciences; Krause, F.F. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    2006-12-15

    Permeability is an important property of reservoir rocks. Small-scale laminar structures within sandstones can influence highly anisotropic permeability fields which control single-phase fluid flow and two-phase mobility of immiscible phases such as oil-water. This study compared permeability trends from horizontal and vertical plugs of the Upper Santonian Virgelle Member sandstone at Writing-on-Stone Provincial Park in southern Alberta. It presented the results of probe permeameter gas flow measurements taken in different orientations on 2 samples from the Viking Formation cored at depth. Permeability anisotropy of laminated sandstones, initially established during deposition, can still be recognized at depth, along with the equivalent relative homogeneity of vertical permeability (kV). Permeability data tied to sedimentological/stratigraphic models is used to examine the controls on permeability distribution and their applicability to subsurface reservoirs. The general permeability trend responded to upward increasing grain size, locally modified by macroburrows, micro-bioturbation and calcareous cements. The results suggest that careful definition of lithofacies can provide the foundation for fluid flow models. The relative homogeneity of vertical permeability structure documented in this study may result from the baffling effect of laminar structure acting as filter. It is expected that cross-laminar fluid flow in such facies will form a uniform and efficient displacement front, by passing fewer pores relative to heterogeneous, fingering layer-parallel flow profile. 49 refs., 2 tabs., 17 figs.

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

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    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.

  10. 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)

  11. Iron deficiency anemia in infants aged 12-15 months in Ahwaz, Iran

    OpenAIRE

    Monajemzadeh Seyed; Zarkesh Mohammad

    2009-01-01

    Background: Iron deficiency anemia (IDA) is one of the most common nutritional problems in the world, especially in developing countries. Infants aged between 4 and 24 months are among the population groups that are most affected by iron deficiency (ID). The aim of this study was to investigate the prevalence of ID and IDA in infants aged 12-15 months, living in Ahwaz, southwest of Iran. Materials and Methods: One hundred and twenty-six infants participated in the study. The mean corpus...

  12. QUALITATIVE AND QUANTITATIVE STUDY OF MUNICIPAL SOLID WASTE IN AHWAZ CITY; WITH EMPHASIS ON HOSPITAL WASTES

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    Gh. Omrani

    1998-09-01

    Full Text Available Qualitative and quantitative analyses of hospital and municipal solid waste are necessary for selecting the best and most appropriate method of health care collection, storage, transportation and disposal of this kind of wastes. Quantitative and qualitative analyses of hospital and municipal wastes have been studied in Ahwaz city during spring 1996. The amount of solid wastes in five regions of the city was 560,000 Kg perday (0.648 Kg per capita. Also, the rate of waste production in 6 hospitals of Ahwaz was 2.54 Kg per bed. The average density of hospital and municipal solid wastes were 443 and 284.5 Kg/m3 respectively. Physical contents of municipal and hospital solid wastes were also investigated. The results were as follows Plastic & rubber (%7.7 , %16.57 ; wood and paper (%11.3, %14.35; textiles (%5.32, %13.76 ; metals (%4.7 , %9.48 ; glass (%4.26 , %4.12. Also degradable materials in hospital and municipal wastes were %29.38 and %64.24 of total sample waste, respectively.

  13. Iron deficiency anemia in infants aged 12-15 months in Ahwaz, Iran

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    Monajemzadeh Seyed

    2009-04-01

    Full Text Available Background: Iron deficiency anemia (IDA is one of the most common nutritional problems in the world, especially in developing countries. Infants aged between 4 and 24 months are among the population groups that are most affected by iron deficiency (ID. The aim of this study was to investigate the prevalence of ID and IDA in infants aged 12-15 months, living in Ahwaz, southwest of Iran. Materials and Methods: One hundred and twenty-six infants participated in the study. The mean corpuscular volume and hemoglobin (Hb, serum ferritin and hematocrit levels were measured. Anemia was defined when Hb < 11g/dL and ID when ferritin < 12µg/mL. Results: The prevalence of ID and IDA was 31.7 and 26.2%, respectively. The tendency to have IDA in infants fed with cow′s milk and infants who did not receive ferrous sulfate was higher than in the other subjects. Conclusion: ID and IDA are common among infants aged 12-15 months living in Ahwaz, Iran. Maintenance of exclusive breastfeeding up to the 4-6th month of life and iron supplementation for the target group is needed.

  14. 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.

  15. 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.

  16. Fungal Contamination of Indoor Public Swimming Pools, Ahwaz, South-west of Iran

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    A Rafiei

    2010-09-01

    Full Text Available "nBackground: Using public swimming pools during different seasons and poor health behavior could be responsible in transmis­sion of fungal disease through pool water and its environment. Therefore, this research was conducted to investi­gate fungal agents of indoor public swimming pools of Ahwaz, capital city of Khouzestan Province, south-west of Iran."nMethods: Ten indoor swimming pools of Ahwaz were investigated during two seasons for 6 months. Water specimens were col­lected by pump and environment samples including shower-bath area, margin of pool walls, dressing rooms, and slip­pers, by sterile carpet pieces. All specimens were cultured in SC and SCC culture media and fungal agents identification were based on macroscopic, microscopic characteristic and complement tests when it was necessary. Data analyzing was per­formed using SPSS version 13 for descriptive analyzing."nResults: A total of 593 samples were collected from different parts of pools. Interestingly in 13 samples from environ­mental places, dermatophytes were isolated as follows: Trichophyton mentagrophytes, T. rubrum, T. verrucosum and Epidermo­phyton floccosum 5, 4, 3 and 1 cases respectively. Ten cases of dermatophytes were isolated from floor of dressing area. Three hundred seventy two saprophytic fungi species and 32 yeasts were recovered from water and environment sur­faces samples. Aspergillus, Penicillium and Mucor were the most common isolated saprophytic fungi."nConclusion: Existence of saprophytic fungi and yeast in pools water seems to be an indicator of their resistance to detergent agents. In addition, yeast water contamination could be from swimmers. Dermatophytes isolation from pools environment ar­eas and foot washing sink, reveals the importance of public swimming pools in disease transmission. Because dressing places are being used by all of the swimmers, take care of hygienic discipline in these places should be noted by health pol­icy markers.

  17. 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

  18. Adenomyosis among samples from hysterectomy due to abnormal uterine bleeding in Ahwaz, southern Iran

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    Maryam Dehghani Mobarakeh

    2012-01-01

    Full Text Available Introduction: Adenomyosis is one of the most common, yet underdiagnosed, underlying causes of abnormal uterine bleeding (AUB. We aimed to evaluate the prevalence of adenomyosis among subjects who underwent hysterectomy due to AUB. Materials and Methods: We studied the pathological specimens from 100 cases of AUB who underwent hysterectomy and were referred to Jundishapur University of Medical Sciences, Ahwaz (Iran from 2007 to 2010. All specimens were reviewed by the same pathologist. Results: Pathological findings included adenomyosis 21%, leiomyoma 30%, adenomyosis and leiomyoma 21%, adenomyosis and other pathological causes 7%, and other pathological causes 21%. The overall prevalence of adenomyosis was 49%. Mean age of the patients was 46.9 ± 7.8 years and the highest frequency of adenomyosis was observed in the age group 30-60 years. Conclusions: Overall prevalence of adenomyosis in the population with AUB (49% that we studied was higher than that in the reports from other populations. Occurrence of isolated adenomyosis in those aged less than 30 years was rare, and adenomyosis was usually accompanied by other lesions.

  19. Sandstones and their attributes

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří; Kidston, J.

    Praha : Academia, 2007 - (Hartel, H.; Cílek, V.; Herben, T.; Jackson, A.; Williams, R.), s. 13-24 ISBN 978-80-200-1577-8 R&D Projects: GA AV ČR IAA3013302 Institutional research plan: CEZ:AV0Z30130516 Keywords : sandstones * sedimentary structures * depositional environment * cementation * sandstone relief, Subject RIV: DB - Geology ; Mineralogy

  20. 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.

  1. 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.

  2. 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...... the throat plugging theory, the effect of heating is found to be reversible with cooling. In laboratory experiments we heated Berea sandstone from 20oC to 80oC and observed a reversible permeability reduction. The permeability of the heated samples increased at higher flow rates. We propose that in...

  3. Stochastic reconstruction of sandstones

    OpenAIRE

    Manwart, C.; Torquato, S.; Hilfer, R.

    2000-01-01

    A simulated annealing algorithm is employed to generate a stochastic model for a Berea and a Fontainebleau sandstone with 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 sandston...

  4. 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...... composition, clay morphology and type of cementation. The reservoir quality of the Solling Member (upper Bunter sandstone) is good in most of the sandstones, but it is poor where abundant clay or pervasive cementations by anhydrite, carbonate or halite occur. Ephemeral fluvial sandstones are dominant in this...... the sandstones are aeolian, weakly cemented and clay-free. Furthermore, they have a wide lateral and fairly constant vertical distribution since large quantities of mature sand were supplied from distant source areas in the Variscan belt....

  5. Stochastic reconstruction of sandstones

    International Nuclear Information System (INIS)

    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. (c) 2000 The American Physical Society

  6. 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. PMID:11088546

  7. 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.

  8. 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

  9. Preliminary study on features of mineralogical zoning of epigenetic alteration at sandstone-type uranium deposit, Dongsheng area, Ordos basin

    International Nuclear Information System (INIS)

    Sandstone-type uranium deposits located in Dongsheng area, northern Ordos basin, occur in Zhiluo Formation, Middle Jurassic. The Zhiluo Formation is divided into two members. The lower member is further divided into two submembers. The lower submember is dominantly composed of grey sandstone being the ore-hosting horizon; the upper submember consists of grey-green sandstone and mudstone. The upper member of Zhiluo Formation is made of mottled medium-fine grained sandstone and mudstone. Through the microscopic observation and study on sandstones of Zhiluo Formation, authors have established a vertical zonation of epigenetic alteration (from the top to the bottom): the limonitization + clayization + carbonation in the mottled fine-grained sandstone of the upper member of Zhiluo Formation; the green alteration (II) (mainly the chloritization of biotite, as well as the chloritization and epidotization of feldspar) + clayization + carbonation in the grey-green sandstone of the upper submember of the lower member of Zhiluo Formation; and the green alteration (I) (mainly the epidotization of feldspar) + carbonation in grey, grey-white sandstone of the lower submember. The epigenetic alteration basically occurs in grey-green sandstone. The sandstone shows grey-green color because it contains much green biotite (not chlorite). The epigenetic alteration in sandstone layer is closely associated with the uranium ore-formation

  10. 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)

  11. Clay mineral variations near Pennsylvanian sandstone channels

    International Nuclear Information System (INIS)

    Large linear sandstone bodies in the Illinois Basin have been interpreted as representing fresh water river channels that flowed through generally marine to brackish Pennsylvanian deltaic environments; fresh water from such channels could have affected deposition of adjacent coal-bearing rocks. Low-sulfur coals are commonly associated with the sandstone bodies, which may also host petroleum, uranium, fresh water, or other resources. Thus techniques to locate such channels would be economically useful. Previous studies have shown that clay mineral distributions and bulk chemistries of clay-rich sediments are affected when fresh waters mix with sea water. Such changes associated laterally with freshwater channels might have caused distinctive clay mineral or chemical patterns to develop around the channels. Mineralogies and chemical compositions of more than 500 mudrock samples taken immediately above the springfield Coal Member of the Petersburg Formation from 52 sections located from channel margins to 63 miles distant were determined to discern patterns that could aid in finding channels

  12. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Sandstone deposits represent a large part of the world's uranium deposits, and are particularly common in the United States of America. Orebodies of this type tend to exhibit many of the following features: (1) tabular or roll shape; (2) cross-bedded grey or green sandstone host rock, generally of Silurian or younger age; (3) a certain minimum thickness of sandstone; (4) mudstone interbedded with the sandstone; and (5) abundant organic matter and pyrite. The orebodies contain mainly uraninite and coffinite, with carnotite and other secondary minerals, and are commonly clustered along mineral trends. (author)

  13. Conversational repair strategies in 3 and 5 year old normal Persian-speaking children in Ahwaz, Iran

    Directory of Open Access Journals (Sweden)

    Zahra Ghayoumi Anaraki

    2013-03-01

    Full Text Available Background and Aim: The ability of conversational repair is a subset of pragmatic language. When the listener does not understand the speaker's intention, and the speaker cannot find a way of repairing the conversation to make his/her massage clear, communication will fail. This study aims to examine and compare the conversational repair skill in two groups of three and five year old children, to determine different conversational repair strategies and compare these skills among these groups.Methods: One hundred and twenty Persian speaking children of three and five years of Ahwaz, Iran, were selected. The study tools were two series of pictures. During the retelling of the pictures the examiner created a situation to elicit a conversational repair strategy. Percentages of the usage of different kinds of conversational repair in each group were calculated and compared using student's t-test.Results: The usage of repetition and inappropriate response is decreased in the group of five year olds compared to the three year olds, but cue-repair and repetition method is increased. The addition method has remained relatively constant. There was a significant difference between average percentage of using repetition (p=0.04 and cue-repair (p=0.001 of the two groups. The percentage of application of repetition method in three year olds and cue-term method in five year olds were significantly higher than other conversational repair strategies.Conclusion: With the increase in age and development of language skills the probability of using more complex and difficult strategies, like the cue-repair method, increases.

  14. 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

  15. Sandstone Turning by Abrasive Waterjet

    Czech Academy of Sciences Publication Activity Database

    Hlaváček, Petr; Cárach, J.; Hloch, Sergej; Vasilko, K.; Klichová, Dagmar; Klich, Jiří; Lehocká, D.

    2015-01-01

    Roč. 48, č. 6 (2015), s. 2489-2493. ISSN 0723-2632 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : turning away from the jet * conventional turning towards the jet * sandstone * abrasive water jet Subject RIV: JQ - Machines ; Tools Impact factor: 2.420, year: 2014 http://www.springerprofessional.de/sandstone-turning-by-abrasive-waterjet/6038028.html

  16. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Three overall factors are necessary for formation of uranium deposits in sandstone: a source of uranium, host rocks capable of transmitting uranium-bearing solutions, and a precipitant. Possible sources of uranium in sandstone-type deposits include groundwaters emanating from granitic highlands, arkosic sediments, tuffaceous material within or overlying the host rocks, connate fluids, and overlying black shales. The first three sources are considered the most likely. Host rocks are generally immature sandstones deposited in alluvial-fan, intermontane-basin or marginal-marine environments, but uranium deposits do occur in well-winnowed barrier-bar or eolian sands. Host rocks for uranium deposits generally show coefficients of permeability on the order of 1 to 100 gal/day/ft2. Precipitants are normally agents capable of reducing uranium from the uranyl to the uranous state. The association of uranium with organic matter is unequivocal; H2S, a powerful reductant, may have been present at the time of formation of some deposits but may go unnoticed today. Vanadium can serve to preserve the tabular characteristics of some deposits in the near-surface environment, but is considered an unlikely primary precipitant for uranium. Uranium deposits in sandstone are divided into two overall types: peneconcordant deposits, which occur in locally reducing environments in otherwise oxidized sandstones; and roll-type deposits, which occur at the margin of an area where an oxidized groundwater has permeated an otherwise reduced sandstone. Uranium deposits are further broken down into four subclasses; these are described

  17. 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

  18. Surface composition of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, W.F.; Oen, A.C.; Strobel, J.F.; Falconer, J.L.; Evans, H.E.

    1986-02-01

    Auger electron spectroscopy (AES) was used to determine the surface composition of Berea sandstone. Changes in the surface composition resulting from cation exchange and surfactant adsorption have also been observed. Surface compositions obtained by AES were compared to bulk analysis as well as X-ray photoelectron spectroscopic analysis (XPS).

  19. Evaluating Berea Sandstone reservoirs in eastern Ashland County, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Hillebrand, L.B.; Coogan, A.H.

    1986-08-01

    The Berea Sandstone is a principal oil and gas reservoir in eastern Ashland County. It is stratigraphically situated above the red and gray Bedford shales and below the black Sunbury shale member of the Cuyahoga Formation, all of which are Late Devonian or Early Mississippian in age. In the study area, the Berea Sandstone is found at depths between 400 and 800 ft. It outcrops in an arcuate band to the north and west of the county. Geophysical logs indicate the reservoir capacity of the Berea is between 8 and 22%, with an average porosity of 15%. Generally, the Berea is a loosely cemented, gray to buff quartzose sandstone with few accessory minerals. The cement may be calcite, silica, or minor ferruginous materials. The reservoir geometry in eastern Ashland County is peculiar because these sands thin and thicken within relatively short distances. The long-standing explanation for this phenomenon is that these sands were deposited in incised river channels that had downcut through the Bedford shales as a result of isolated uplift in north-central Ohio. Recent subsurface mapping in this area shows that the continuity of these channels may be challenged. Also, well-ticket data indicate that red shale occurs above the Berea sands. This occurrence and the soft-sediment deformation between the Bedford Shale and Berea Sandstone indicate that these units were deposited contemporaneously rather than as two separate events.

  20. Surface composition of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ramierz, W.F.; Evans, H.; Faiks, J.; Falconer, J.L.; Oen, A.

    1983-10-01

    Auger electron spectroscopy (AES) has been used to determine the surface composition of Berea sandstone. Changes in surface composition due to cation exchange and surfactant adsorption have also been observed. The application of AES to nonconducting materials such as sandstones requires special sample preparation and operating conditions to eliminate destructive charging effects. Surface compositions obtained by AES were compared to bulk analyses as well as to X-ray photoelectron spectroscopic (XPS) analysis. Surface compositions of aluminum, iron, sodium and potassium were significantly higher than bulk compositions. After contact with distilled water, AES analysis showed the loss of potassium and sodium from the surface. AES analysis of Berea contacted with MgCl and CaCl solutions showed increased adsorption of chlorine over that contacted with NaCl and KCl solutions. Trends in the adsorption of the surfactants Texas number2 and Triton X-100 were observed by AES.

  1. 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...

  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...... to address the effects of temperature on permeability. Therefore, different aspects of sandstone permeability are investigated in this research project. Data from a range of sources including: published literature; a database containing over 120 tight gas sandstone samples; new flow...... permeability to sandstone texture. The simple physically based Kozeny (1927) equation, relates permeability to porosity and specific surface per pore volume, or equivalent pore size, for a homogeneous porous medium with a uniform pore size. As pore sizes in sandstones can range from nanometres to micrometres...

  3. 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.

  4. 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

  5. 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.

  6. "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

  7. Surface energy characterization of sandstone rocks

    Science.gov (United States)

    Arsalan, Naveed; Palayangoda, Sujeewa S.; Burnett, Daniel J.; Buiting, Johannes J.; Nguyen, Quoc P.

    2013-08-01

    The fundamental forces of adhesion are responsible for the spreading of fluids such as crude oil/brine on the reservoir rock surface. These physico-chemical interactions determine the surface energetics of a reservoir and thus their wetting phenomena. Inverse Gas Chromatography (IGC) is introduced to characterize the surface energy of sandstones (Ottawa sand and Berea sandstone). The surface chemistry of the sandstone rocks is further elucidated using X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) techniques. The behavior of the polar and non-polar interaction forces was investigated at varying water coverage and at different temperatures. The results indicated that in general as the water coverage increased, the Lifshitz-van der Waals component of surface energy decreased to nearly that of the bulk water, while the acid-base component also showed a decreasing trend. The Lifshitz-van der Waals component of surface energy always decreased with increase in temperature, while the acid-base properties showed contrasting trends in line with changes in surface chemistry of the sandstones, due to the change in temperature. Finally, the wetting properties arising in reservoir sandstones were related to the surface chemistry of the reservoir fluids and their interactions with the reservoir rock surface.

  8. Petrology of late Paleozoic-early Mesozoic Pyeongan Group sandstones, Gohan area, South Korea and its provenance and tectonic implications

    Science.gov (United States)

    Yu, Kang-Min; Lee, Gie-Hyeon; Boggs, Sam

    1997-04-01

    Carboniferous to Triassic strata of the Pyeongan Group crop out in the Gohan area, northeastern South Korea. These strata consist, in ascending order, of the Hongjeom, Sadong, Gobangsan, and Nogam formations. Sandstones in these formations comprise three distinct framework-mineral suites. Suite 1 sandstones (Hongjeom Formation through the Middle Member of Gobangsan Formation) are quartz and quartzose arenites/wackes that contain abundant quartz, little or no feldspar, and few acid volcanic clasts. Heavy minerals are mainly tourmaline, rutile, and zircon. Suite 2 sandstones (Upper Member of Gobangsan Formation) are lithic arenites/wackes characterized by moderate quartz content, low amounts of feldspar, and moderate to abundant volcanic clasts. Sphene is the predominant heavy mineral. Suite 3 sandstones (Nogam Formation) are feldspathic arenites/wackes distinguished by low quartz content, moderate to abundant feldspar, and low amounts of acid volcanic clasts. The heavy-mineral assemblage of the Nogam Formation is characterized particularly by epidote and sphene. Feldspar-poor Suite 1 sandstones were derived from a source terrain rich in quartzite and quartzose sandstone. Abundant quartz and stable heavy minerals were supplied initially during Late Carboniferous time to a shallow-marine shelf, which changed gradually near the end of Carboniferous time to a nonmarine, paralic platform setting. Electron probe microanalysis shows that Suite 1 tourmaline was derived originally from Li-poor granitoids, pegmatites, and Ca-poor aplite and metapsammite. Petrographic evidence demonstrates that the scarcity of feldspars in Suite 1 sandstones is not the result of diagenetic intrastratal solution. Major changes in mineralogy from Suite 1 into Suite 2 and Suite 3 sandstone indicate changes in provenance. Suite 2 sandstones were derived from diorite, granodiorite, acid volcanic rocks, and possibly some metamorphic rocks, which furnished feldspars and sphene. The appearance of

  9. 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

  10. Sandstone cementation and its geomorphic and hydraulic implications

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří

    2005-01-01

    Roč. 44, - (2005), s. 21-24. ISSN 1682-5519. [Sandstone Landscapes in Europe. Past, Present and Future. International Conference on Sandstone Landscapes /2./. Vianden, 25.05.2005-28.05.2005] R&D Projects: GA AV ČR(CZ) IAA3013302 Institutional research plan: CEZ:AV0Z30130516 Keywords : sandstone * paleohydraulics * geomorphology * siliceous cement * carbonate cement * ferruginous cement * sandstone landsforms Subject RIV: DB - Geology ; Mineralogy

  11. The effect of firing on Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, J.C.; Hawkins, B.F. (Petroleum Recovery Inst., Calgary, AB (Canada)); Churcher, P.L. (Pan Canadian Petroleum Ltd. (CA))

    1991-03-01

    The petroleum industry uses Berea sandstone as a standard testing material. It is often fired to desensitize indigenous clays. In this paper the author study the effect of firing by comparing unfired Berea to samples fired at 1000{degrees} C for 5 hours. The observed changes in the petrographic and petrophysical parameters are then related to single- and two-phase coreflood data.

  12. 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

  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. 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

  15. 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.

  16. Diagenetic effects on porosity-permeability relationships in red beds of the Lower Triassic Bunter Sandstone Formation in the North German Basin

    Science.gov (United States)

    Olivarius, Mette; Weibel, Rikke; Hjuler, Morten L.; Kristensen, Lars; Mathiesen, Anders; Nielsen, Lars H.; Kjøller, Claus

    2015-05-01

    Carbonate and anhydrite cement, clay clasts and inter-granular clay are the main components that reduce reservoir quality in the studied Bunter Sandstone Formation. The impacts of these parameters on porosity and permeability are determined by combining petrographic mineral quantification with conventional core analysis of samples from the Danish part of the North German Basin. The depositional environments are considered because they largely control the distribution of cements, clays and grain sizes. The lateral variability of depositional environments is defined by the position in the basin and the proximity to the source areas. The stratigraphic distribution of depositional environments is related both to local topography and to climate because high aridity promoted aeolian deposition. The Bunter Sandstone Formation has high porosity and permeability in most of the sandstone intervals in the northern North German Basin. The reservoir quality is good as long as the cements and clays are present as confined bodies that leave the remaining pore spaces available for flow. In contrast, inter-granular clay and pervasive cementation hinder virtually all flow through the sandstone. The ephemeral fluvial deposits have an average porosity and permeability of 20.3% and 810 mD, respectively, and the values are 24.6% and 807 mD for the aeolian sandstones, excluding the unconsolidated aeolian sands which presumably have higher porosity and permeability. The aeolian sandstones of the Volpriehausen Member have very good reservoir quality since they have a thickness of about 25 m, are laterally continuous, are largely clay-free and the cement occurs in small amounts. The sandstones of the Solling Member consist mainly of ephemeral fluvial deposits, which generally have good reservoir quality. However, some intervals have high contents of inter-granular clays or pervasive carbonate, anhydrite or halite cement and these components reduce the permeability significantly. The lateral

  17. Radionuclide transport in sandstones with WIPP brine

    International Nuclear Information System (INIS)

    Retardation factors (R) have been measured for the transport of 3H, /sup 95m/Tc, and 85Sr in WIPP brine using St. Peter, Berea, Kayenta, and San Felipe sandstone cores. If tritium is assumed to have R=1, /sup 95m/Tc has R=1.0 to 1.3 and therefore is essentially not retarded. Strontium-85 has R = 1.0 to 1.3 on St. Peter, Berea, and Kayenta, but R=3 on San Felipe. This is attributed to sorption on the matrix material of San Felipe, which has 45 volume % matrix compared with 1 to 10 volume % for the others. Retardation factors (R/sub s/) for 85Sr calculated from static sorption measurements are unity for all the sandstones. Therefore, the static and transport results for 85Sr disagree in the case of San Felipe, but agree for St. Peter, Berea, and Kayenta

  18. 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.

  19. Cathodoluminescence characteristics of sandstone and the implications for sandstone type No. 512 uranium deposit

    International Nuclear Information System (INIS)

    Cathodoluminescence (CL) technique, as a special petrologic tool, has been applied to the studies of uranium hosted sandstone from No. 512 uranium deposit located in Xinjiang Autonomous Region, Northwest China. The detrital grains including quartz, feldspar, debris and cements display distinguishing CL properties. The quartz grains mainly demonstrate brown and dark blue CL, feldspar grains demonstrate blue and bright blue CL, calcite cement displays bright yellow-orange and orange-red CL with significant CL zoning, while the debris, mud and sand cements have dark red CL, multicolor CL or non-luminescence. The characteristics of overgrowth, fracture healing, and the original contact relations of detrital grains appear much more significant with CL than that with conventional visual methods. Much more information can be contributed by CL technique to decipher the provenance area, to explain the cementation, consolidation and other diagenesis processes of sandstone. The CL technique also provides and efficient tool for identifying detrital grains and cements, and for more precisely estimating the proportions of various detrital grains and cement components in sandstone. The CL emission of uranium hosted sandstone revealed the existence of radiation-damage rims of quartz grains at the places with a little or no uranium minerals nearby, which may imply a uranium-leaching episode during the diagenesis of sandstone

  20. 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)

  1. 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)

  2. Modelling Quartz Cementation of Quartzose Sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Wangen, Magnus

    1999-10-01

    Porosity estimation in sandstones is an important part of oil reservoir quality estimations, as porosity is lost during burial because of mechanical compaction and quartz cementation. In this report, cementation of quartzose sandstones is modelled assuming that the main source of silica is quartz dissolved at stylolites. The cementation process is shown to operate in one of two different regimes depending on the Damkohler number for diffusion. The regime, where diffusion of silica from the stylolites is a faster process than precipitation, is characterized by a nearly constant supersaturation between the stylolites. This regime, which spans the depth interval of quartz cementation for close stylolites, allows approximate analytical expressions for the porosity evolution as a function of time and temperature. An expression is derived for the temperature where half the initial porosity is lost during constant burial along constant thermal gradient. This expression is used to study the sensitivity of all parameters which enter the cementation process. The cementation process is shown to be particularly sensitive to the activation energy for quartz dissolution. The expression for the porosity decrease under constant burial is generalized to any piecewise linear burial and temperature history. The influence of the burial histories on the cementation process is studied. 32 refs., 16 figs., 1 tab.

  3. Sandstone landforms shaped by negative feedback between stress and erosion

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Soukup, J.; Vaculíková, J.; Filippi, Michal; Schweigstillová, Jana; Mayo, A. L.; Mašín, D.; Kletetschka, Günther; Řihošek, J.

    2014-01-01

    Roč. 7, č. 8 (2014), s. 597-601. ISSN 1752-0894 R&D Projects: GA ČR GA13-28040S Institutional support: RVO:67985831 ; RVO:67985891 Keywords : sandstone * sandstone landsforms * stress * erosion Subject RIV: DB - Geology ; Mineralogy Impact factor: 11.740, year: 2014

  4. Berea Sandstone reservoirs in Ashland and Medina Counties, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Hillebrand, L.B.; Coogan, A.H.

    1984-12-01

    The Berea Sandstone is one of the better known rock formations in Ohio. It occurs at shallow depths throughout a broad belt in central Ohio and crops out to the north and west of these counties. In Ashland and Medina Counties, the Berea may be divided into two separately identifiable units. The upper unit, called the blanket Berea in outcrop, is approximately equivalent to the cap Berea in the subsurface. The second unit, which lies below the cap Berea varies considerably in its thickness. The traditional, long-standing, and generally accepted view is that the Berea Sandstone was deposited in Ashland and Medina Counties in southward-flowing river channels. More recent drilling in these counties has demonstrated that these sand channels are not continuous, but are isolated sandstone bodies in which petroleum has accumulated. The reservoir capacity of the Berea is between 8 and 22% with an average porosity of 15%. The sandstone consists of loosely cemented, medium to fine-grained quartz with only rare shale breaks below the cap Berea. In Ashland and Medina Counties, Berea wells generally produce oil. Initial production in this area ranges between 1 or 2 bbl and to 40 BOPD after treatment. Reservoirs in the Berea Sandstone generally are productive where the sandstones are thick. They are also productive where the sandstone is thinner, but high on structure. Although a high structural position is preferred, the critical consideration is the thickness of the sandstone body and the reservoir geometry.

  5. 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

  6. 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.

  7. Experimental Study of Cement - Sandstone/Shale - Brine - CO2 Interactions

    Directory of Open Access Journals (Sweden)

    Carroll Susan A

    2011-11-01

    Full Text Available Abstract Background Reactive-transport simulation is a tool that is being used to estimate long-term trapping of CO2, and wellbore and cap rock integrity for geologic CO2 storage. We reacted end member components of a heterolithic sandstone and shale unit that forms the upper section of the In Salah Gas Project carbon storage reservoir in Krechba, Algeria with supercritical CO2, brine, and with/without cement at reservoir conditions to develop experimentally constrained geochemical models for use in reactive transport simulations. Results We observe marked changes in solution composition when CO2 reacted with cement, sandstone, and shale components at reservoir conditions. The geochemical model for the reaction of sandstone and shale with CO2 and brine is a simple one in which albite, chlorite, illite and carbonate minerals partially dissolve and boehmite, smectite, and amorphous silica precipitate. The geochemical model for the wellbore environment is also fairly simple, in which alkaline cements and rock react with CO2-rich brines to form an Fe containing calcite, amorphous silica, smectite and boehmite or amorphous Al(OH3. Conclusions Our research shows that relatively simple geochemical models can describe the dominant reactions that are likely to occur when CO2 is stored in deep saline aquifers sealed with overlying shale cap rocks, as well as the dominant reactions for cement carbonation at the wellbore interface.

  8. 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.

  9. 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

  10. Hydrological modelling in sandstone rocks watershed

    Science.gov (United States)

    Ponížilová, Iva; Unucka, Jan

    2015-04-01

    The contribution is focused on the modelling of surface and subsurface runoff in the Ploučnice basin. The used rainfall-runoff model is HEC-HMS comprising of the method of SCS CN curves and a recession method. The geological subsurface consisting of sandstone is characterised by reduced surface runoff and, on the contrary, it contributes to subsurface runoff. The aim of this paper is comparison of the rate of influence of sandstone on reducing surface runoff. The recession method for subsurface runoff was used to determine the subsurface runoff. The HEC-HMS model allows semi- and fully distributed approaches to schematisation of the watershed and rainfall situations. To determine the volume of runoff the method of SCS CN curves is used, which results depend on hydrological conditions of the soils. The rainfall-runoff model assuming selection of so-called methods of event of the SCS-CN type is used to determine the hydrograph and peak flow rate based on simulation of surface runoff in precipitation exceeding the infiltration capacity of the soil. The recession method is used to solve the baseflow (subsurface) runoff. The method is based on the separation of hydrograph to direct runoff and subsurface or baseflow runoff. The study area for the simulation of runoff using the method of SCS CN curves to determine the hydrological transformation is the Ploučnice basin. The Ploučnice is a hydrologically significant river in the northern part of the Czech Republic, it is a right tributary of the Elbe river with a total basin area of 1.194 km2. The average value of CN curves for the Ploučnice basin is 72. The geological structure of the Ploučnice basin is predominantly formed by Mesozoic sandstone. Despite significant initial loss of rainfall the basin response to the causal rainfall was demonstrated by a rapid rise of the surface runoff from the watershed and reached culmination flow. Basically, only surface runoff occures in the catchment during the initial phase of

  11. Metallogenetic features and perspective evaluation of sandstone-type uranium mineralization in Hailaer Basin, NE, China

    International Nuclear Information System (INIS)

    Hailaer basin is located at the Mongolia-Erguna microplate between Siberian and North-China plates. The basement of the basin is composed of Precambrian igneous and metamorphic rocks, which experienced multiple granitization, and Late Paleozoic, Mesozoic granites and acidic-intermediate volcanics constituting a uranium-enriched provenance area. The sedimentary cover of the basin consists of continental sedimentary series of Late Jurassic to Tertiary. Of them, Lower Cretaceous (Damouguaihe Formation) clastics of alluvial, fan-delta and fluvial facies rich in organic matter are the main uranium ore-hosting series. Numerous uranium occurrences have been found at the western part of the basin, and uranium mineralization mainly occurs in coarse-grained clastics of the second and third members of Damouguaihe Formation. Uranium ore bodies usually are tabular, a few roll-shaped. The thickness of individual orebody ranges from 0.3m to 5m. Ore grade commonly is 0.0n% with the encountered highest grade of 0.38%. Uranium in ores is in adsorption form, heterogeneously disseminated in the cement of sandstone. No independent uranium mineral has been found. Associated elements in ores include Mo, V, Se, Sc, and Re. Discovered uranium mineralization in the basin approximately occurs at the same elevation intervals (660-680m), suggesting the paleo-phreatic origin. Uranium mineralization is mostly localized in permeable sandstone units of fluvial and fan-delta facies with high content of organic matter. Ore-formation age is supposed to be the period from K2 to N when the ore-hosting sedimentary series outcropped at the surface and was eroded. High content of uranium in provenance area, existence of permeable ore-hosting sandstone units and the oxidation (phreatic and interlayer) alteration of ore-hosting sandstone after its deposition under arid climate environments are key factors determining the perspective potential of uranium ore-formation. (author)

  12. 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.

  13. 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. 

  14. Deformation and fracture of Berea sandstone

    Science.gov (United States)

    Bernabe, Yves; Brace, W. F.

    Samples of Berea sandstone were deformed to failure at different values of the confining pressure, Pc (from 10 to 250 MPa), and the pore pressure, Pp (from 0 to 130 MPa), at different strain rates and with pore fluids of different viscosities. Axial stress and strain were recorded in all tests. In addition, volumetric strain was measured in tests run at a strain rate of 2×10-5 s-1. The microstructure of several deformed samples was observed using the SEM. When the pore fluid was distilled water, the tests were performed in truly drained conditions at all strain rates. Results indicated that Pc and Pp had roughly opposite effects. With increasing Pc-Pp the samples showed a smooth transition from localized brittle fracture to uniformly distributed cataclastic flow. The data collected agreed well with a theoretical model in which strain localization is considered as an instability in the material constitutive relations. In Berea sandstone the stabilizing mechanism appeared to be the compaction caused by fragmentation of grains and the rearrangement of these fragments in the preexisting pore space. When the pore fluid was a highly viscous silicone fluid and the strain rate was 2×10-3 s-1, the sample behavior was not consistent with truly drained conditions. In the brittle regime a decrease in pore pressure within the sample due to dilation produced dilatancy-hardening. The samples deformed in the ductile regime, on the other hand, showed a loss of strength and signs of embrittlement. This weakening/embrittiement was caused by an increase in pore pressure within the sample due to compaction.

  15. 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

  16. Hematite-enriched sandstones and chromium-rich clays - Clues to the origin of vanadium-uranium deposits in the Morrison Formation, southwestern Colorado and southeastern Utah, USA

    International Nuclear Information System (INIS)

    Fluvial sandstones of the Salt Wash Member, Upper Jurassic Morrison Formation, southwestern Colorado and southeastern Utah, host tabular, epigenetic vanadium-uranium (V-U) deposits. Laterally within a few tens of meters of some of the V-U deposits are two distinct accumulations -one enriched in iron (hematite), and the other chromium (Cr-rich mixed-layer clays). The iron-enriched sandstones commonly occur at the contact between red and gray (buff in outcrop) sandstones, are dark red and generally color banded. Between the iron and V-U deposits, chromium accumulated in gray argillaceous sandstones that contain small coalified plant fragments. Variations in Eh, oriented parallel to facies changes but perpendicular to regional ground-water flow, controlled the spatial distribution of iron, chromium, and V-U deposits. Depositional facies within the Salt Wash Member are characterized by fluvial axes containing thick sandstones, and by well-drained floodplains marginal to the fluvial axes. Laterally continuous sandstones contained an organic acid bearing solution that mobilized iron as Fe(II). This reducing solution mixed with alkaline U-, Cr-, and V-bearing, oxygenated pore waters from floodplain sediments. Due to mixing, dissolved iron in the reducing solution was oxidized and precipitated as ferric hydroxide. Chromium, as chromate (CrO42-), was chemically reduced by organic compounds in the vicinity of minor accumulations of detrital plant fragments and was incorporated into authigenic clay minerals. Dissolved U and V were not reduced by the organic compounds; instead, reduction and precipitation occurred by reaction with localized strongly reducing (sulfidic) pore waters. The tabular geometry of V-U deposits was a product of the hydrologic characteristics of the host rock or a brine-freshwater interface. Similar redox processes may explain the association of Cr, V, and U in the Mecsek deposits, Hungary, and deposits hosted by the Jurassic Entrada Sandstone

  17. Adsorption of sodium alkyl aryl sulfonates on sandstone. [Berea and Benton Tar Springs sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, J.B.; Dilgren, R.E.

    1976-01-01

    Equilibrium adsorption isotherms of commercial alkyl aryl sulfonates (petroleum sulfonates), and pure alkyl aryl sulfonates on disaggregated Berea and Benton Tar Springs sandstones were determined. Adsorption isotherms of commercial sulfonates were found to contain maxima, which did not necessarily correspond to the measured C.M.C. At adsorption maxima, surface coverage corresponded to about one half monomolecular layer of sulfonate, but, at high surfactant concentrations, coverage sometimes amounted to only about one-tenth of a monolayer. Pure alkyl aryl sulfonates were synthesized and adsorption on sandstone determined. These materials were found to yield conventional adsorption isotherms, with adsorption plateaus at about one half a monolayer of surface coverage. Apparently, adsorption maxima are unique to impure sulfonates. Selectivity of adsorption with respect to molecular weight and structural type was studied. Structure of petroleum sulfonate and accompanying mineral oil was determined as were structures of sulfonate and mineral oil that had been equilibrated with sandstone. Comparison showed no selectivity of adsorption based on carbon number distribution or structural type. However, aggregates relatively rich in mineral oil were found to be selectively adsorbed.

  18. 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

    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...... cement is more abundant and better developed in the lower parts of reservoir units, whereas it may be scarce and poorly developed in upper parts, especially within the oil zone. Below the oil-water contact, the growth of chlorite may have continued for a longer period, resulting in more dense coatings...

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Salt and ice crystallisation in porous sandstones

    Science.gov (United States)

    Ruedrich, Joerg; Siegesmund, Siegfried

    2007-03-01

    Salt and ice crystallisation in the pore spaces causes major physical damage to natural building stones. The damaging effect of these processes can be traced back to physically induced stress inside of the rock while crystallizing. The increasing scientific research done during the past century has shown that there are numerous parameters that have an influence on the weathering resulting from these processes. However, the working mechanisms of the stress development within the rock and its material dependency are still subject to discussion. This article gives an overview of salt and ice weathering. Additionally, laboratory results of various sandstones examined are presented. Salt crystallisation tests and freeze/thaw tests were done to obtain information about how crystallisation weathering depends on material characteristics such as pore space, water transportation, and mechanical features. Simultaneous measuring of the length alternating during the salt and ice crystallisation has revealed detailed information on the development of crystal in the pore spaces as well as the development of stress. These findings can help to understand the damaging mechanisms.

  4. Baseline groundwater chemistry : the Sherwood Sandstone of Devon and Somerset

    OpenAIRE

    Bearcock, J.M.; Smedley, P. L.

    2012-01-01

    This report describes the regional geochemistry of groundwater from the Sherwood Sandstone aquifer of Devon and Somerset. In order to assess the likely natural baseline chemistry of the groundwater in the area, information has been gathered from the strategic collection of 21 new groundwater samples, and from collation of existing groundwater, rainfall, mineralogical and geochemical data. The Sherwood Sandstone aquifer results from continental deposition during the early Triass...

  5. 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...

  6. Mineralization of carbon dioxide sequestered in volcanogenic sandstone reservoir rocks

    OpenAIRE

    Zhang, Shuo

    2014-01-01

    We proposed to use volcanogenic sandstones for CO2 sequestration. Such sandstones with a relatively high percentage of volcanic rock fragments (VRF) could be a promising target for CO2 sequestration in that they have a sufficient percentage of reactive minerals to allow substantial mineralization of injected scCO2, which provides the most secure form of CO2 storage, but can also be porous and permeable enough to allow injection at acceptable rates. The limitation in using volcanogenic sandsto...

  7. Kaolinite Mobilisation in Sandstone:Pore Plugging vs. Suspended Particles

    OpenAIRE

    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 suggest that this effect is due to kaolinite clay mobilisation from the quartz grain surface; the mobilised particles subsequently plug the pore throats and reduce the permeability irreversibly. The e...

  8. 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).

  9. 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.

  10. Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Deliverable 2.5.4, Ferron Sandstone lithologic strip logs, Emergy & Sevier Counties, Utah: Volume I

    Energy Technology Data Exchange (ETDEWEB)

    Allison, M.L.

    1995-12-08

    Strip logs for 491 wells were produced from a digital subsurface database of lithologic descriptions of the Ferron Sandstone Member of the Mancos Shale. This subsurface database covers wells from the parts of Emery and Sevier Counties in central Utah that occur between Ferron Creek on the north and Last Chance Creek on the south. The lithologic descriptions were imported into a logging software application designed for the display of stratigraphic data. Strip logs were produced at a scale of one inch equals 20 feet. The strip logs were created as part of a study by the Utah Geological Survey to develop a comprehensive, interdisciplinary, and qualitative characterization of a fluvial-deltaic reservoir using the Ferron Sandstone as a surface analogue. The study was funded by the U.S. Department of Energy (DOE) under the Geoscience/Engineering Reservoir Characterization Program.

  11. Comparison of mineralization geologic character of interlayer oxidized zone sandstone type uranium deposit and 2082 paleovalley sandstone type uranium deposit

    International Nuclear Information System (INIS)

    On the basis of analyzing mineralization geologic character of of interlayer oxidized zone sandstone type uranium deposit and 2082 paleovalley sandstone type uranium deposit, we compared the similarities and differences on the lithology and lithofacies of host structure, paleoclimate background on formation of uranium deposit, the way and period of oxidization (mineralization), orebody shape and space distribution character of both deposits. Then to conclude mineralization geologic character of both deposits and hope to cause the attention of the experts

  12. Members of the Agency

    International Nuclear Information System (INIS)

    The new Member since the last list of Member States was issued (INFCIRC/2/Rev.63) is Palau which deposited its Instrument of Acceptance of the Statute on 2 March 2007. The Attachment hereto shows the dates on which the present 144 Member States became Members

  13. Serialization of elongated members

    International Nuclear Information System (INIS)

    Elongated members such as nuclear fuel end plugs are provided to a robot by a vibratory feeder. The robot singly inserts the members into a character stamper or marker and then removes them and drops them down a chute to an inspection site. The member is inserted into a character reader and inspected. Unacceptably stamped members are rejected and for each accepted member the stamper is advanced to a next character. Thus, a next member is stamped with the next character, or permutation of characters, the robot already having provided a new member to the stamper

  14. 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.

  15. Sandstone type uranium deposits in NW China

    International Nuclear Information System (INIS)

    Northwest China named here indicates the territory of China north of Kunlun-Qilian-Qingling mountain systems and west of Great Higgan Range, containing most of the significant sandstone type uranium deposits in China. The territory, some 2500 km long, in average 650 km wide and about 2.86x106km2 in area, comprises seven Mesozoic-Cenozoic basin-forming domains: the Tianshan-Junggar, the Tarimu, the Altun, the Alxan-Corridor, the Qaidam, the Eren-Hailar and the Ordos. Most domains include several sub-domains, but the Tarimu, the Qaidam and the Ordos domains contain one sub-dome only. Known deposits are mainly distributed in the Tianshan sub-domain of the Tianshan-Junggar domain and the Eren sub-domain of the Eren-Hailar domain. Besides, Dongsheng uranium mineralized has been discovered in the Ordos domain in latest years with a considerable amount of uranium resources/ reserves (Chen Anping et al., 2004). The host sandstones deposited in four different environments: 1) the cratonic basin, open and wide, characterised with shallow water depth and low subsidence rate, such as Junggar, Tarimu and Ordos basins; 2) the intra-continental down-faulted basin, usually divided by uplifts into second depressions and third order sags, characterised with deeper water depth and higher subsidence rate, exemplified by the basins in Eren-Hailar domain; 3) the compressive intermountain flexural basin, mostly of medium/small in size and narrowelongated in shape, occupying the intermediate position between previous two in water depth and subsidence rate, such as inter-mountain basins in Tianshan sub-domain; and 4) the erosive gully, formed on the hillside fields in stream head area and wide spread along the piedmont slope of Yingshan Mountains and the second uplifts within the range of the Eren basin. Meanwhile, uranium ore deposits/fields formed under three quite distinct tectonic regimes: the slight arching regime, characterized by the deformation mainly in shape of dome with vertical

  16. 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.

  17. Development of Shear Banding in Berea Sandstone

    Science.gov (United States)

    Riedel, J. J.; Labuz, J. F.

    2004-05-01

    Closed-loop, servo-controlled testing was used to investigate the development of shear failure in Berea sandstone under low confining pressure. The experiments were performed with the University of Minnesota Plane-Strain Apparatus, designed to allow the failure plane to propagate in an unrestricted manner. Deformation was imposed into the strain softening regime and controlled so that the specimens remained intact. Thin-section microscopy provided direct observation in, adjacent to, and around the tip of the rupture zone. The shear band appeared to initiate near a stress concentration, either the corner of the specimen or, when present, an imperfection (3 mm diameter hole) introduced into the specimen. Intragranular microcracking was the dominant observable failure mechanism. The intensity of grain cracking was greatest near the initiation point and decreased as the failure surface was traced towards the tip. Areas of high crack density also appeared to have the greatest amount of grain size reduction and there seemed to be a larger amount of pore space. In areas where intragranular microcracks were distinguishable, (e.g. near the tip of the rupture zone), microcracks showed very little or no shear displacement, suggesting the features were not reoriented after formation. Microcrack orientations showed a dominant direction of -16 degrees from the maximum principal stress direction and -26 degrees from the failure surface. A numerical imaging technique was developed to provide an efficient means for analyzing the relative porosity of epoxy-impregnated thin-sections. The code was set up to receive a digital image (*.bmp), where three parameters (R, G, and B) describe the color of each pixel. The intensity of the R channel consistently defined the boundary of grain and pore space and was used to differentiate blue pore space from the white grains composing the matrix. Porosity increase within the rupture zone was 3-4 grain diameters wide. An absence of notable

  18. Sedimentology and diagenesis of a rift basin lacustrine sandstone: Pematang group, central Sumatra, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Janks, J.S.; Kelley, P.A.; Williams, H.H.

    1986-05-01

    The Central Sumatra basin is a back-arc basin that formed during the Paleocene as a series of half-graben structures. These early formed half-graben structures were filled with nonmarine clastics and lacustrine sediments of the Pematang Group, sourced from local highland areas. The Pematang Group consists of the Lower Red Beds, Brown Shale, Coal Zone Member, and Lake Fill Formation (in ascending order). The Pematang Group sedimentology is intimately related to the regional and basinal tectonic development and history. Sandstones of the Pematang Group are predominantly sublitharenites and litharenites; feldspars are rare. Sandstone diagenesis is relatively uniform regardless of the depositional environment. Diagenetic modifications include compaction, early calcite and dolomite cementation, quartz overgrowth formation, unstable rock-fragment dissolution, kaolinite precipitation, siderite formation, and local illite formation. Secondary porosity accounts for up to 50% of the effective porosity and was created by rock-fragment dissolution. This dissolution is probably caused by the organic acids released during kerogen maturation. Stable isotope data from diagenetic siderite are presented.

  19. 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.

  20. 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.

  1. 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...

  2. 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...

  3. Geological principles of exploration for sandstone-hosted uranium deposits

    International Nuclear Information System (INIS)

    Although the importance of sandstone-hosted uranium deposits has seemingly faded in recent years due to the discovery of large, high -grade deposits elsewhere, a forecasted energy shortage in the near future will probably necessitate a new look at sedimentary basins as a source of uranium. Back-arc basins adjacent to calcalkaline source areas are especially favourable if they are filled with fluvial, post-Devonian sediments. Syn- and post-depositional tectonics play an important role in the sedimentation-mineralisation process and should be investigated. The oxidation-reduction state of the sandstones is a valid prospecting tool. Sedimentological environments govern the permeability and vegetal matter content of sandstones and directly control uranium mineralisation

  4. Regional distribution regularity of sandstone uranium deposits in Asian continent and prospecting strategy for sandstone uranium deposits in China

    International Nuclear Information System (INIS)

    Since the 1980's, after the discovery of numerous sandstone uranium deposits in Middle Asia (Kazakhstan, Uzbekistan) many large sandstone uranium deposits have been found in both Russia and Mongolia. So that Asia has become the most concentrated region of sandstone uranium deposits. The known sandstone uranium deposits occur mostly in a arcual tectonic belt constrained from the north by the Siberian continental block, and the Tarim-North China continental block from the south. This belt is named by Russian geologists as the Central Asian Mobile Belt, and some Chinese geologists call it the 'Mongolian Arc'. A lot of large and super large metallic, non-metallic, gold, polymetallic, porphyry copper and gold, massive sulphide and uranium deposits (of sandstone and volcanic types) with different origin and various types concentrated occur in this belt. The abundant and colourful mineral resources in the region are closely associated with the specific geologic-tectonic evolution of the above belt. It is necessary to strengthen the detailed geologic research and uranium prospecting in the region

  5. 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

  6. 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...

  7. Stratigraphy and petroleum potential of Berea sandstone in Larkin and Williams fields, Midland and Bay Counties, Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Gunn, G.R.

    1986-08-01

    The Berea is an Early Mississippian deltaic sandstone confined to the eastern side of the Michigan basin. The Berea Sandstone consists of three members: upper, middle, and lower. Only the upper and middle members are present in the Larkin and Williams area. The middle member is the main reservoir, and scanning electron microscope studies indicate that the sand has primary, interparticle porosity with some secondary leaching of interstitial clays and feldspathic grains. Over the past 5 years, wells have been drilled 2500 ft into the Berea along a structure between Midland and Bay Counties. The structure is a northwest-southeast-trending anticline that plunges northwest into the basin. A review of the wells drilled along this anticline reveals a progression of structural-stratigraphic traps within the middle Berea member. At the southeast end of each reservoir (the updip end), a stratigraphic pinchout cuts across the middle Berea member creating a barrier to oil migrating updip along the northwest-southeast structural trend. These pinch-outs are narrow with a north-northeast orientation and are considered to be abandoned, mud-filled channels cutting across an apron sheet sand, which is interpreted to be a beach-strand-plain complex. Because the middle Berea member has excellent porosity and permeability, many wells in the field have flowed oil with initial production ranging between 75 and 350 BOPD. The original oil in place is estimated to be more than 23 million bbl of oil; only 1.4 million bbl of oil has been produced.

  8. 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...

  9. 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...

  10. Cathodoluminescence investigations on quartz cement in sandstones of Khabour Formation from Iraqi Kurdistan region, northern Iraq

    DEFF Research Database (Denmark)

    Omer, Muhamed Fakhri; Friis, Henrik

    The Ordovician deltaic to shallow marine Khabour Formation in Northern Iraq consists mainly of sandstone with minor siltstone and interbedded shale. The sandstones are pervasively cemented by quartz that resulted in very little preserved primary porosity. Cathodoluminescence and petrographic stud...

  11. Features of sandstone paleorelief preserved: The Osek area, Miocene, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Mikuláš, Radek

    2005-01-01

    Roč. 44, - (2005), s. 35-38. ISSN 1682-5519. [Sandstone Landscapes in Europe. Past, Present and Future. International Conference on Sandstone Landscapes /2./. Vianden, 25.05.2005-28.05.2005] R&D Projects: GA AV ČR(CZ) IAA3013302 Institutional research plan: CEZ:AV0Z30130516 Keywords : paleorelief * sandstone phenomenon * Miocene * sandstone landscape * palaeorelief * silcrete * fossil roots * Neogene * Pleistocene * Czech Republic Subject RIV: DB - Geology ; Mineralogy

  12. 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)

  13. 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'.

  14. Sandstone Relief Geohazards and their Mitigation: Rock Fall Risk Management in the Bohemian Switzerland National Park

    Czech Academy of Sciences Publication Activity Database

    Vařilová, Zuzana; Zvelebil, J.

    2005-01-01

    Roč. 44, - (2005), s. 53-58. ISSN 1682-5519. [Sandstone Landscapes in Europe. Past, Present and Future. International Conference on Sandstone Landscapes /2./. Vianden, 25.05.2005-28.05.2005] Keywords : sandstones * rock-slope instability * rock fall * risk evalution and mitigation * monitoring net * remedial works Subject RIV: DO - Wilderness Conservation

  15. 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

  16. Berea Sandstone gas reservoirs in Portage County, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Coogan, A.H.; Heath, L.L.

    1984-12-01

    The Mississippian Berea Sandstone is a reservoir for shallow gas in Randolph and Suffield townships of Portage County, Ohio. The Berea Sandstone is well known in Ohio from its outcrops at the outskirts of Cleveland. It is among the more productive formations in Ohio where it yields gas, oil, or gas and oil at moderate to very shallow depths. The great differences in reservoir quality, sandstone distribution, and producibility in Berea oil and gas fields are partly related to the use of the term Berea for several sandstone bodies that produce from different structural and stratigraphic settings. In Portage County, the Berea Sandstone is up to 60 ft (18 m) thick and has a porosity in the 15-25% range. The sand is white, medium to fine-grained quartz, poorly cemented, and without substantial shale interbeds. The reservoir lies below the Cap Berea, a gray, cemented thin bed at the base of the Sunbury Shale (driller's Coffee shale). In Portage County, the sand is currently interpreted as fluvial or deltaic. Within the field, thickness of the reservoir and hydrocarbon saturated zone varies little. Natural gas is produced from the top 30 ft (9 m) of the reservoir. The reservoir energy is water drive. The gas fields lie just updip from a steep structural terrace interpreted as a fault zone. The trap for the fields is anticlinal and the Sunbury Shale is the seal. New wells drilled into the reservoir at 400-500 ft (122-152 m) in depth produce gas without water. Initial open flow tested up to 1.0 MMCFGD at an initial reservoir pressure of about 80 psig (552 kPa).

  17. Fast evolving conduits in clay-bonded sandstone: Characterization, erosion processes and significance for the origin of sandstone landforms

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Svetlik, D.; Soukup, J.; Schweigstillová, Jana; Válek, Jan; Sedláčková, M.; Mayo, A.L.

    2012-01-01

    Roč. 177, December (2012), s. 178-193. ISSN 0169-555X R&D Projects: GA AV ČR IAA300130806 Institutional support: RVO:67985891 ; RVO:68378297 Keywords : sandstone * erosion * piping * tensile strength * conduit * landform Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.552, year: 2012

  18. 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

  19. Effect of firing on petrophysical properties of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ma, S.; Morrow, N.R. (New Mexico Petroleum Recovery Research Center, Socorro, NM (United States))

    1994-09-01

    In many laboratories studies, cores are fired as a preliminary step for one or more of three reasons: (1) to ensure strongly water-wet mineral surfaces by burning off organic contaminants; (2) to stabilize clay minerals and so reduce problems of clay swelling and fines migration; and (3) to minimize problems arising from ion exchange. The general objectives of firing are to improve reproducibility and to reduce the number of variables that may affect the results of displacement tests. Berea sandstone is widely used as a model rock for studying fluid flow through porous media. Firing has been a common step in core preparation. Changes in properties of Berea sandstone caused by firing were determined from petrophysical measurements and petrographic studies. Results show that firing usually creates more problems than it solves. Use of fired cores generally should be avoided.

  20. 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.

  1. Adsorption of foam-forming surfactants in Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Mannhardt, K.; Novasad, J.J. (Petroleum Recovery Inst., Calgary, AB (Canada)); Jha, K.N. (Canada Centre for Mineral and Energy Technology, Ottawa, ON (Canada))

    1994-02-01

    Adsorption measurements carried out with representativs of four classes of surfactant suitable for foam flooding (alpha olefin sulphonate, internal olefin sulphonate, linear xylene sulphonate, and betaine) on Berea sandstone at different conditions of temperature and salinity are described. Adsorption of the anionic surfactants from a low salinity brine is low, but increases substantially at moderate salinities. Limited solubility of the anionic surfactants in aqueous media tends to drive these surfactants to the solid/liquid interface and can also lead to increased surfactant loss through precipitation. The betaine is highly soluble, but adsorbs very strongly on sandstone. Adsorption of this surfactant can be reduced by mixing it with an anionic surfactant. 30 refs., 11 figs., 7 tabs.

  2. 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.

  3. Biohydrometallurgy of low-grade, carbonate bearing sandstone uranium ore

    International Nuclear Information System (INIS)

    An alkaline, carbonate bearing, sandstone uranium ore was leached microbiologically. Pure as well as mixed cultures of local isolated of Thiobacillus ferrooxidans were employed. Sandstone uranium ore contained 5% calcite, 2.3% Fe2O3, minor amounts of pyrite and was alkaline in nature. Shake flask studies employing mixed and pure culture of thiobacilli were carried out. Ore was amended with different oxidizable inorganic energy sources such as FeSO4, slag and sulfur etc. The leaching capability of local isolate of T. ferrooxidans was also compared with that of pure ATCC culture number-sign 13661 of this bacteria. It was found that the local isolate leached out uranium more efficiently as compared with exenic culture. Further, slag was found to be economical energy source for these bacteria. Mixed culture studies revealed that the percentage of leached uranium was increasing with increase in the proportion of T. ferrooxidans in the inoculum

  4. CO2 sequestration in feldspar-rich sandstone: Coupled evolution of fluid chemistry, mineral reaction rates, and hydrogeochemical properties

    Science.gov (United States)

    Tutolo, Benjamin M.; Luhmann, Andrew J.; Kong, Xiang-Zhao; Saar, Martin O.; Seyfried, William E.

    2015-07-01

    To investigate CO2 Capture, Utilization, and Storage (CCUS) in sandstones, we performed three 150 °C flow-through experiments on K-feldspar-rich cores from the Eau Claire formation. By characterizing fluid and solid samples from these experiments using a suite of analytical techniques, we explored the coupled evolution of fluid chemistry, mineral reaction rates, and hydrogeochemical properties during CO2 sequestration in feldspar-rich sandstone. Overall, our results confirm predictions that the heightened acidity resulting from supercritical CO2 injection into feldspar-rich sandstone will dissolve primary feldspars and precipitate secondary aluminum minerals. A core through which CO2-rich deionized water was recycled for 52 days decreased in bulk permeability, exhibited generally low porosity associated with high surface area in post-experiment core sub-samples, and produced an Al hydroxide secondary mineral, such as boehmite. However, two samples subjected to ∼3 day single-pass experiments run with CO2-rich, 0.94 mol/kg NaCl brines decreased in bulk permeability, showed generally elevated porosity associated with elevated surface area in post-experiment core sub-samples, and produced a phase with kaolinite-like stoichiometry. CO2-induced metal mobilization during the experiments was relatively minor and likely related to Ca mineral dissolution. Based on the relatively rapid approach to equilibrium, the relatively slow near-equilibrium reaction rates, and the minor magnitudes of permeability changes in these experiments, we conclude that CCUS systems with projected lifetimes of several decades are geochemically feasible in the feldspar-rich sandstone end-member examined here. Additionally, the observation that K-feldspar dissolution rates calculated from our whole-rock experiments are in good agreement with literature parameterizations suggests that the latter can be utilized to model CCUS in K-feldspar-rich sandstone. Finally, by performing a number of reactive

  5. 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...

  6. Microbial Penetration through Nutrient-Saturated Berea Sandstone

    OpenAIRE

    Jenneman, Gary E.; McInerney, Michael J.; Knapp, Roy M.

    1985-01-01

    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 pen...

  7. Strength curves for shales and sandstones under hydrostatic confining pressures

    International Nuclear Information System (INIS)

    The experimental data for the effect of confining pressures on the fracture stress have been analysed for shales and sandstones. The normalized compressive strengths are found to lie in a narrow region so that Ohnaka's equation for crystalline rocks, can be fitted to the data. The fitted parameters are physically reasonable and indicate that the functional dependence of strength on porosity, strain rate and temperature is independent of the confining pressures. (author)

  8. 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...

  9. Self organised conduit network in sandstone quarry: Characterization and evolution

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Světlík, D.; Soukup, J.; Schweigstillová, Jana; Mayo, A.

    2011-01-01

    Roč. 43, č. 5 (2011), s. 252. ISSN 0016-7592. [2011 GSA Annual Meeting & Exposition: Archean to Anthropocene: The past is the key to the future. 09.10.2011-12.10.2011, Minneapolis] R&D Projects: GA AV ČR IAA300130806 Institutional research plan: CEZ:AV0Z30460519 Keywords : sandstone * piping * sapping Subject RIV: DB - Geology ; Mineralogy

  10. Plant invasions in sandstone areas of the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Hadincová, Věroslava; Mandák, Bohumil; Bímová, Kateřina; Mahelka, Václav

    Praha: Academia, 2007 - (Hartel, H.; Cílek, V.; Herben, T.; Jackson, A.; Williams, R.), s. 217-219 ISBN 978-80-200-1577-8 R&D Projects: GA ČR(CZ) GA526/05/0430; GA AV ČR(CZ) IAA6005206 Institutional research plan: CEZ:AV0Z60050516 Keywords : invasions * environment * sandstones Subject RIV: EF - Botanics

  11. Surface contamination and changes of mechanical damping in Berea sandstone

    Science.gov (United States)

    Brunner, Will Marlin

    Small changes in the pore fluid chemistry of Berea sandstone cause significant changes in mechanical damping. A method of detecting contaminants in porous rocks is under ongoing development. Here I report several laboratory measurements done in support of this development, including that of a large difference in mechanical damping between clean and chemically treated Berea sandstone. I develop a model of a surface-chemistry related damping mechanism, and qualitatively compare results from calculations to experimental results. I rule out other damping mechanisms, and conclude that the observed damping is due to surface chemistry effects (contact angle hysteresis). To help verify experimental results, an anelastic structure with calculable damping properties was built. Damping of this structure was measured by the same method used for damping measurements on Berea sandstone. Results from these measurements show good agreement to the calculated response of the structure in the frequency range 0.03--1 Hz.* *This dissertation includes a CD that is compound (contains both a paper copy and a D as part of the dissertation. The CD requires the following applications: Adobe Acrobat.

  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. PMID:15380409

  13. Controls on CO2 Mineralization in Volcanogenic Sandstone Reservoir Rocks

    Science.gov (United States)

    Zhang, S.; DePaolo, D. J.; Xu, T.; Voltolini, M.

    2013-12-01

    We proposed to use volcanogenic sandstones for CO2 sequestration. Such sandstones with a relatively high percentage of volcanic rock fragments (VRF) could be a promising target for CO2 sequestration in that they have a sufficient percentage of reactive minerals to allow substantial mineralization of injected scCO2, which provides the most secure form of CO2 storage, but can also be porous and permeable enough to allow injection at acceptable rates. Modeling results from reactive transport code TOUGHREACT show that as much as 80% CO2 mineralization could occur in 1000 years in rocks with 10-20% volcanic rock fragments and still allow sufficient injectivity so that ca. 1 megaton of CO2 can be injected per year per well. The key to estimating how much CO2 can be injected and mineralized is the relationship between permeability (or injectivity) and reactive mineral content. We have sampled examples of volcanogenic sandstones from Miocene Etchegoin Formation, central California to examine these relationships. Characterizations of these samples by SEM, XRF and XRD show that they are rich in reactive minerals with around 32% plagioclase, 10% clinopyroxene, 2% diopside, and 1% ilmenite. Porosities range from 10% to 20%, and permeabilities range from 10 mD to 1000 mD. Batch experiments are also in progress to obtain realistic reactivity estimates. Figure 1. Outcrop photo and photomicrograph showing volcanic mineralogy and abundant pore space from Miocene Etchegoin Formation, central California

  14. Properties and durability assessment of glauconitic sandstone: A case study on Zamel sandstone from Bohemian Cretaceous Basin (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Martinec, Petr; Vavro, M.; Ščučka, Jiří; Mašláň, M.

    2010-01-01

    Roč. 115, 3/4 (2010), s. 175-181. ISSN 0013-7952 R&D Projects: GA ČR GP101/07/P512; GA ČR(CZ) GA103/07/1662 Institutional research plan: CEZ:AV0Z30860518 Keywords : building stone * sandstone * physical properties Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.442, year: 2010 http://www.sciencedirect.com/science

  15. Provenance of the Lower Triassic Bunter Sandstone Formation: implications for distribution and architecture of aeolian vs. fluvial reservoirs in the North German Basin

    DEFF Research Database (Denmark)

    Olivarius, Mette; Weibel, Rikke; Friis, Henrik; Boldreel, Lars Ole; Keulen, Nynke; Thomsen, Tonny B.

    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 zircon ages found...... analysis is an invaluable tool of correlation and subdivision of the Bunter Sandstone in this marginal basin setting. This is because the succession includes many hiatuses so the cyclo-, magneto-, and bio-stratigraphic frameworks established elsewhere in the basin cannot readily be applied here. Zircon......-grade metamorphism, whereas a secondary age population with a peak at 300 Ma matches the timing of volcanism and magmatism at the Carboniferous/Permian boundary in the northern Variscan belt. The Ringkøbing-Fyn High also supplied some sediment tothe Volpriehausen Member. The zircon ages obtained from the Solling...

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

    OpenAIRE

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

    2004-01-01

    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 m...

  17. Regional and local anomalies of uranium and thorium in rocks near sandstone-type uranium deposits in Pennsylvania and Colorado

    International Nuclear Information System (INIS)

    The geochemistry of U and Th in about 500 shales and sandstones from the Catskill Formation in Pennsylvania and the Morrison and adjoining formations in the Uravan mineral belt of Colorado has been investigated to evaluate the magnitude and extent of regional detrital U and Th anomalies, and more local anomalies in the paleoaquifers through which U was transported to form the deposits. Background U and Th are negatively related to grain size and positively related to Al, Ti, and other components of the fine fraction. Weak anomalies in U and Th are accentuated by examination of residuals (deviations) from regressions of U or Th against Al, or U against Th. Some anomalies are accentuated by analysis of extractable U rather than total U. In the Catskill Formation near Jim Thorpe, Pa., the Duncannon-Clarks Ferry Member, which hosts roll-type U ores near Penn Haven Junction, is enriched in both U and Th by 20 to 50%, compared to the underlying Long Run Member which lacks U occurrences; it is also enriched compared to laterally equivalent Duncannon-Clarks Ferry samples 20 to 120 km to the southwest. Zircons from the sandstones show a similar pattern. A U-rich source area apparently was exposed and supplying detritus to the Jim Thorpe area in Duncannon-Clarks Ferry time. The oxidized paleoaquifer through which U reached the roll-type U occurrences contains a fourfold enrichment of U, apparently by adsorption of U from the ground water which formed the rolls. In Colorado, no regional depositional trends, either lateral or vertical, were found in the U and Th content of the host Salt Wash Member, but the entire Morrison Formation may be slightly enriched in U and Th relative to underlying units. The Salt Wash sediments near Uravan contain about twice background amounts of U

  18. 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.

  19. 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.

  20. 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.

  1. Experimental Analysis of Hybrid Fracture in Berea Sandstone

    Science.gov (United States)

    Bobich, J. K.; Chester, F. M.; Chester, J. S.

    2004-12-01

    Previous triaxial extension experiments investigating the transition from extension fracture to shear fracture in low porosity, polycrystalline Carrara marble demonstrate abrupt changes in strength and a continuous transition in fracture orientation and morphology with increasing confining pressure, Pc. New tests on Berea sandstone investigate the same transition in a porous aggregate. Notch cut cylinders (30 mm neck diameter) of Berea sandstone (18% porosity, 0.15 mm average grain size, 80% quartz, 20% feldspar, and trace rutile and kaolinite) were extended in a triaxial apparatus from 0 to 160 MPa confining pressure at a rate of 20 μ m/s. Stress at fracture is characterized by the least compressive principal stress, S3, and maximum compressive principal stress, S1 (S1=Pc). An abrupt change in fracture strength at Pc=50 MPa corresponds to a change from pure macroscopic extension fracture to mixed-mode opening and shear (hybrid) fracture. Within the extension fracture regime, S3 at failure becomes slightly more tensile with an increase in Pc, unlike the constant tensile strength observed for marble. Within the hybrid and shear fracture regimes, S3 at failure becomes more compressive with an increase in Pc. The angle between the fracture surface and S1 increases continuously with Pc, consistent with the marble results. In both rock types, hybrid fractures appear as linked, stepped extension fractures; the length of extensional segments decreases with increasing pressure. The abrupt change in failure strength at the transition from extension to hybrid modes in both rock types likely reflects the increase in mean stress that suppresses the propagation of extension fractures, and the interaction between closely-spaced stepped cracks. In the extension fracture regime, the different dependence of fracture strength on Pc for sandstone and marble may reflect differences in grain scale deformation mechanisms.

  2. Borehole Breakouts in Berea Sandstone Reveal a New Fracture Mechanism

    Science.gov (United States)

    Haimson, B. C.

    - Vertical drilling experiments in high-porosity (22% and 25%) Berea sandstone subjected to critical true triaxial far-field stresses, in which σH (maximum horizontal stress) >σv (vertical stress) >σh (least horizontal stress), revealed a new and non-dilatant failure mechanism that results in thin and very long tabular borehole breakouts that have the appearance of fractures, and which counterintuitively develop orthogonally to σH. These breakouts are fundamentally different from those induced in crystalline rocks, as well as limestones and medium-porosity Berea sandstone. Breakouts in these rocks are typically dog-eared in shape, a result of dilatant multi-cracking tangential to the hole and subparallel to the maximum far-field horizontal stress σH, followed by progressive buckling and shearing of detached rock flakes created by the cracks. In the high-porosity sandstone a narrow layer of grains compacted normal to σH is observed just ahead of the breakout tip. This layer is nearly identical to ``compaction bands'' observed in the field. It is suggested that when a critical tangential stress concentration is reached along the σh spring line at the borehole wall, grain bonding breaks down and a compaction band is formed normal to σH. Debonded loose grains are expelled into the borehole, assisted by the circulating drilling fluid. As the breakout tip advances, the stress concentration ahead of it persists or may even increase, extending the compaction band, which in turn leads to breakout lengthening.

  3. 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

  4. Influence of Intermediate Stress on Yielding of Berea Sandstone

    Science.gov (United States)

    Jourine, S.; Karner, S. L.; Kronenberg, A. K.; Chester, F. M.

    2003-12-01

    The onset of brittle failure of Berea sandstone has been investigated under varying stress states by subjecting solid and hollow cylindrical samples to confining pressure Pc (to 120 MPa) and axial stress σ z (to 260 MPa) in a conventional triaxial deformation apparatus. Inelastic yielding of solid and hollow samples is marked by cascading acoustic emissions and axial displacements that depart from the initial linear elastic response. For hollow samples, uniaxial (σ z > σ Θ = σ r = 0) and biaxial (σ z > σ Θ > σ r = 0 or σ Θ > σ z > σ r = 0) stress states are obtained with deviators that (1) are maximum at the inner wall, (2) decay in a predictable manner with increasing radius prior to yielding, and (3) are insensitive to frictional boundary conditions at piston-sample contacts throughout much of the sample. X-ray CT scans of deformed samples reveal different modes of failure associated with the stress states imposed. Zones of anomalous X-ray density within hollow samples that mark deformed sandstone are localized near the inner wall, nearly midway between sample ends, and inner walls have lost their cylindrical geometry. Axial cavities of hollow samples become elliptical when axial stress is the intermediate principal stress (σ z = σ 2), with geometries resembling wellbore break-outs used to infer in-situ horizontal stresses in scientific drilling studies, while toroidal spalls are developed when the tangential stress is the intermediate stress (σ Θ = σ 2). Our results for solid specimens under conventional triaxial conditions (σ z > σ r = σ Θ > 0) are in agreement with results reported for Berea sandstone. However, the results for hollow specimens require a yield criterion that includes intermediate stress σ 2. Yield criteria that fit our combined data may be expressed in terms of first and second invariants of stress I1 and J2; for example, using the modified Wiebols and Cook (1968) criterion, J21/2 = A + B I1 + C I12, data for Berea

  5. The streaming potential of liquid carbon dioxide in Berea sandstone

    OpenAIRE

    Moore, Jeffrey R.; Glaser, S D; Morrison, H.F.; Hoversten, G M

    2004-01-01

    We report here, for the first time, evolution of the streaming potential coupling coefficient as liquid carbon dioxide infiltrates Berea sandstone. Using 125 Omega-m tap water, the coupling coefficient determined before and after each CO2 flood of five samples averaged approximately -30 mV/0.1 MPa. After liquid CO2 passed through the specimens displacing all mobile pore water, trapped water remained and the coupling coefficient was approximately -3 mV/0.1 MPa. A bound water limit of the coupl...

  6. Three-phase relative permeability of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Oak, M.J.; Baker, L.E. (Amoco Production Co., Tulsa, OK (US)); Thomas, C.C. (Amoco Corp., Naperville Research Center, IL (US))

    1990-08-01

    Reservoir engineering calculations frequently require consideration of coexisting oil, water, and gas phases. Such three-phase flow occurs when oil is displaced by simultaneous gas/water flow as in CO{sub 2}, water-alternating-gas flooding, steam-flooding, or other enhanced recovery processes. For this reason, reservoir simulators generally include three-phase relative permeability prediction methods. This paper presents two- and three-phase relative permeabilities measured on a water-wet fired Berea sandstone core with a fully automated steady-state method to investigate prediction methods experimentally.

  7. Contaminant-induced mechanical damping in partially saturated Berea sandstone

    Science.gov (United States)

    Brunner, W. M.; Spetzler, H. A.

    2002-08-01

    We have measured mechanical damping in partially saturated Berea sandstone that is strongly dependent on the presence of a small amount of oil. This effect is observed as a function of water saturation and average strain amplitude. These observations are presented as evidence of a damping mechanism previously observed and characterized in artificial cracks. We conclude that this damping effect is due to surface chemistry changes in the rock, and infer that seismic attenuation can be used to monitor small changes in pore fluid chemistry under certain conditions.

  8. 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.

  9. 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.

  10. The streaming potential of liquid carbon dioxide in Brea Sandstone

    OpenAIRE

    Moore, J.; GLASER, S; Morrison, F.; Hoversten, G M

    2004-01-01

    We report here, for the first time, evolution of the streaming potential coupling coefficient as liquid carbon dioxide infiltrates Berea sandstone. Using 125 Omega-m tap water, the coupling coefficient determined before and after each CO2 flood of five samples averaged approximately -30 mV/0.1 MPa. After liquid CO2 passed through the specimens displacing all mobile pore water, trapped water remained and the coupling coefficient was approximately -3 mV/0.1 MPa. A bound water limit of the ...

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

    International Nuclear Information System (INIS)

    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 solutions only uranium and small amounts of vanadium were present. (author)

  12. Plasma resistant structural member

    International Nuclear Information System (INIS)

    The present invention provides a plasma resistant ceramic material of a plasma confining device for a tokamak thermonuclear device. Namely, the structural member of the present invention comprises a ceramic-based fibrous composite material having a matrix mainly comprising SiC and fibers composited in the matrix, as a constitution undergoing heat fluxes from plasmas. It is constituted such that it undergoes heat fluxes from plasmas by way of a surface in the direction having the highest heat conductivity. Since the fibers are a reinforcing material for enhancing the toughness of the SiC matrix, SiC type fibers are used. With such a constitution, the structural member has excellent properties such as high temperature strength, high temperature creeping characteristics, high heat stability, elasticity, heat conductivity and sputtering resistance, in addition to provide a high melting point (high sublimation temperature) and a low atomic weight. (N.H.)

  13. 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.

  14. 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

  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. 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.

  17. Investigation of Sandstones Wetting by X-ray Microtomography

    International Nuclear Information System (INIS)

    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.

  18. Relative wetting properties of crude oils in Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    McGhee, J.W.; Crocker, M.E.; Donaldson, E.C.

    1979-01-01

    Sixty-one oils were collected from 21 states and the wettability of each oil determined at both 25 and 60/sup 0/C. Independent wettability determinations were made on 21 samples incubated for a minimum of 1,000 hours at 60/sup 0/C. All determinations were made using Berea sandstone and a synthetic brine. The sulfur and nitrogen content, interfacial tension, and acid numbers were obtained and, while attempts wre made to correlate these parameters with wettability, no simple correlations were discovered. However, residual oil was demonstrated to be dependent upon wettability. For the range studied--that is, neutral to water-wet--residual oil saturations were observed to decrease as wettability varied from water-wet to neutral. The polar organic compounds were extracted from the crude oils, and the amount of extract was compared to the wetting properties of the oils, but considerable variance in the data was observed. However, addition of 5 percent polar extract to a mineral oil consistently lowered the wettability number of the mineral oil-brine-Berea sandstone system by an amount greater than 40 percent.

  19. Dispersion analysis of velocity and attenuation in Berea sandstone

    Science.gov (United States)

    Winkler, Kenneth W.

    1985-07-01

    Ultrasonic velocity and attenuation measurements were made on dry, brine- and oil-saturated Berea sandstone and fused glass beads. The results for fused glass beads are consistent with the predictions of Biot theory. They indicate that as predicted, the Biot absorption/dispersion mechanism shifts to higher frequencies as the fluid viscosity increases. Similar data for Berea sandstone are not consistent with Biot theory, since observed velocities are generally higher than predicted. Using the Biot theory, we calculate low- and high-frequency velocities for the liquid-saturated samples. "Biot dispersion" is then defined as the percent difference between the low- and high-frequency limits. "Apparent dispersion" is defined as the percent difference between the measured ultrasonic velocity and the low-frequency Biot limit. Comparison of these two measures of dispersion gives insight into the presence of a non-Biot absorption/dispersion mechanism. Whenever the apparent dispersion is larger than the Biot dispersion, the extra dispersion is interpreted as being caused by a local flow relaxation. To be consistent with attenuation data, this relaxation must be distributed over at least five to six decades in frequency.

  20. Multinuclear NMR Imaging of Fluid Phases in Berea Sandstone

    Science.gov (United States)

    Sarkar, S. N.; Dechter, J. J.; Komoroski, R. A.

    Multinuclear NMR of 7Li, 19F, and 1H has been investigated as a method for discriminating multiple fluid phases in porous rock. Good 7Li NMR images from LiCl brine in saturated Berea sandstone were obtained within a few hours at 1 × 1 × 5 mm 3 resolution using a low-TE, 3D volume imaging sequence. At 4.7 T, the 7Li T1 was 750 ms, and T2 was 10 ms. High-quality 19F and 1H images of a model fluorinated injectant (trifluorotoluene) in Berea were obtained at 0.4 × 0.4 × 3 mm 3 resolution in a few hours. Fluorine-19 imaging was found to be easier than 1H imaging due to the narrower 19F resonance and comparable T1 and T2 in Berea sandstone. Lithium-7 and 19F imaging offer alternatives for discriminating aqueous and organic phases unambiguously in flooded oil cores, especially where 1H signals for the two phases are unresolved.

  1. 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.

  2. 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.

  3. 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.

  4. Modelling of a diffusion-sorption experiment on sandstone

    International Nuclear Information System (INIS)

    The results of a diffusion-sorption experiment on a sample of Darley Dale sandstone, using simulated groundwater spiked with a mixture of 125I, 85Sr and 137Cs, are modelled by a one-dimensional porous medium approach in which sorption is described by Freundlich isotherms. The governing equations are solved analytically for the special case of a linear isotherm, and numerically using the computer code RANCHDIFF for non-linear isotherms. A set of time-dependent, ordinary differential equations is obtained using the Lagrange interpolation technique and integrated by Gear's variable order predictor-corrector method. It is shown that the sorption behaviour of 85Sr can be modelled successfully by a linear isotherm, using a sorption parameter consistent with batch-sorption tests. The behaviour of 137Cs may be modelled by a non-linear isotherm, but the amount of 137Cs sorbed is less than that anticipated from batch-sorption tests. 125I is assumed to be non-sorbing and is used to determine the porosity of the sandstone. (author) 10 figs., 4 tabs., 6 refs

  5. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Members since the last list of Member States was issued (INFCIRC/2/Rev.66) are Bahrain, Burundi, Congo and Lesotho which deposited their Instruments of Acceptance of the Statute on 23 June 2009, 24 June 2009, 15 July 2009 and 13 July 2009, respectively. The Attachment hereto shows the dates on which the present 150 Member States became Members

  6. 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

  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.63) is Palau which deposited its Instrument of Acceptance of the Statute on 2 March 2007. The Attachment hereto shows the dates on which the present 144 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.58) is Kyrgyzstan, which deposited the instrument of acceptance of the Statute on 10 September 2003. The list shows the dates on which the present 137 Member States became Members

  9. 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.65) is the Sultanate of Oman which deposited its Instrument of Acceptance of the Statute on 5 February 2009. The Attachment hereto shows the dates on which the present 146 Member States became Members

  10. 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

  11. 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.60) is Chad, which deposited the instrument of acceptance of the Statute on 2 November 2005. The Attachment hereto shows the dates on which the present 139 Member States became Members

  12. Nonequilibrium and nonlinear dynamics in Berea and Fontainebleau sandstones: Low-strain regime

    Science.gov (United States)

    Pasqualini, Donatella; Heitmann, Katrin; Tencate, James A.; Habib, Salman; Higdon, David; Johnson, Paul A.

    2007-01-01

    Members of a wide class of geomaterials are known to display complex and fascinating nonlinear and nonequilibrium dynamical behaviors over a wide range of bulk strains, down to surprisingly low values, e.g., 10-7. In this paper we investigate two sandstones, Berea and Fontainebleau, and characterize their behavior under the influence of very small external forces via carefully controlled resonant bar experiments. By reducing environmental effects due to temperature and humidity variations, we are able to systematically and reproducibly study dynamical behavior at strains as low as 10-9. Our study establishes the existence of two strain regimes separated by ɛM. At strains below ɛM the material is nonlinear and quasi-equilibrium thermodynamics applies as evidenced by the success of Landau theory and a simple macroscopic description based on the Duffing oscillator. At strains above ɛM the behavior becomes truly nonequilibrium, as demonstrated by the existence of material conditioning, and Landau theory no longer applies. The main focus of this paper is the study of the first region, but we also comment on how our work clarifies and resolves previous experimental conflicts, as well as suggest new directions of research.

  13. Sandstone columns of the 3rd Nile Cataract (Nubia, Northern Sudan)

    Czech Academy of Sciences Publication Activity Database

    Cílek, Václav; Adamovič, Jiří; Suková, L.

    Wroclaw: University of Wroclaw, 2012 - (Duszynski, F.; Swirad, Z.). s. 11-11 [Sandstone Landscapes (3.). 25.04.2012-28.04.2012, Kudowa-Zdrój] Institutional research plan: CEZ:AV0Z30130516 Keywords : geoarchaeology * sandstones * 3rd Nile Cataract Subject RIV: DB - Geology ; Mineralogy

  14. Origin of regular cavities in European sandstones: field evidence for dissolution of carbonate and silica cement

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří; Mikuláš, Radek; Mertlík, J.

    Wroclaw : University of Wroclaw, 2012 - (Duszynski, F.; Swirad, Z.). s. 7-7 [Sandstone Landscapes (3.). 25.04.2012-28.04.2012, Kudowa-Zdrój] Institutional research plan: CEZ:AV0Z30130516 Keywords : sandstones * cavities * carbonate concretions * cement dissolution Subject RIV: DB - Geology ; Mineralogy

  15. New investigations on the salt weathering of Cretaceous sandstones, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Schweigstillová, Jana; Šímová, Veronika; Hradil, David

    Luxembourg: Travaux scientifiques du Musée national d'histoire naturelle, 2005 - (Ries, C.; Krippel, Y.), s. 177-179 ISSN 1682-5519. [Sandstone landscapes in Europe: Past, present and future. Vianden (LU), 25.05.2005-28.05.2005] Institutional research plan: CEZ:AV0Z30460519 Keywords : aluminium * rain water * sandstone Subject RIV: DD - Geochemistry

  16. Holocene fire dynamics and forest composition in the Elbe Sandstone area

    Czech Academy of Sciences Publication Activity Database

    Bobek, Přemysl

    Wroclaw: Uniwersytet Wroclawski, 2013 - (Migoń, P.; Kasprzak, M.), s. 23-24 ISBN 978-83-62673-29-2. [Sandstone Landscapes. Diversity, Ecology and Conservation. 3rd International Conference on Sandstone Landscapes. Kudowa-Zdrój (PL), 25.08.2012-28.08.2012] Institutional support: RVO:67985939 Keywords : Pinus silvestris * fire Subject RIV: EF - Botanics

  17. 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...

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  1. A special kind of sandstone type uranium deposit in Northeastern Ordos Basin, China

    International Nuclear Information System (INIS)

    The large Dongsheng sandstone type uranium deposit was discovered recently in northeastern Ordos Basin, China. It is a unique kind of deposit, different from other known sandstone type deposits because of its distinctive signatures. It is generally controlled by a transitional zone between greenish and greyish sandstones, both indicating presently reduced geochemical environments. The greenish colour of the paleo-oxidized sandstones is mainly due to chloritization and epidotization related to oil and gas secondary reduction processes. The deposit, which is of more complex origin, has undergone not only paleo-oxidization mineralization process, but also oil-gas fluid and hydrothermal reworking processes and therefore is genetically different from other known sandstone uranium deposits,. The metallogenic model for this uranium deposit is put forward, and exploration outcomes summarized in this paper. (author)

  2. 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.

  3. 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

  4. Cathodoluminescence investigations on quartz cement in the sandstones of Khabour Formation from Iraqi Kurdistan Region, Northern Iraq

    DEFF Research Database (Denmark)

    Omer, Muhamed Fakhri; Friis, Henrik

    2014-01-01

    The Ordovician deltaic to shallow marine Khabour Formation in Northern Iraq consists mainly of sandstone with minor siltstone and interbedded shale. The sandstones are pervasively cemented by quartz that resulted in very little preserved primary porosity. Cathodoluminescence and petrographic stud...

  5. 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

  6. 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

  7. 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....

  8. Flow of a miscible in a Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, F.

    1976-01-01

    A mathematical model for the miscible displacement of a resident fluid by a surfactant solution in a Berea sandstone is derived from first principles, using the concept of volume averaging. The single phase model is scaled and solved by a state variable, finite difference scheme. From the results of the simulation, an experimental program is designed to determine the main model parameters. These include rock parameters (porosity, dead-space volume), fluid properties (binary diffusion coefficient) and flow properties (dispersion coefficient) obtained from displacement experiments. These data are important factors which are needed for the simulation of more complex systems such as the displacement of tertiary residual oil and formation water by aqueous surfactant solutions.

  9. Slow dynamics in the nonlinear elastic response of Berea sandstone

    Science.gov (United States)

    Ten Cate, James A.; Shankland, Thomas J.

    A typical resonance curve—measured acceleration versus drive frequency—made on a thin bar of rock shows peak bending with a softening (nonlinear) modulus as drive levels are increased. The shapes of these nonlinear resonance curves were found in earlier work to depend somewhat on sweep rate; these “slow dynamics” are now examined and quantified. We have measured slow dynamics in a 0.3 m long, 50 mm diameter bar of Berea sandstone under ambient conditions. Peak strain levels during the experiments ranged from 10-11 to 10-5 at driving frequencies near 4 kHz, the fundamental longitudinal resonance frequency of the bar. Slow dynamics begin to manifest themselves at strain amplitudes above 10-6 at ambient conditions and at the onset of nonlinear peak bending. Strains above this value condition the rock, altering its response for minutes to hours after the drive has been turned off.

  10. 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.

  11. X-ray microtomography study of a sandstone reservoir rock

    International Nuclear Information System (INIS)

    This paper presents the pore space characterization of a sandstone reservoir rock carried out with a microfocus X-ray computed tomography (μ-CT). The resulting spatial resolution of the image was 3.8 μm, which allowed a very good visualization and enabled a geometric quantification of grains and pores. A total of 956 μ-CT slices were taken to render a 3-D volume of the specimen. These CT slices were processed in order to characterize the geometrical microstructure of the sample: total porosity and pore size distribution. The possibility of having high-resolution 3-D μ-CT images reveals a promising scenario for studies and applications in porous media characterization. It is possible to simulate fluid invasion in these μ-CT structures and estimate their petrophysical properties

  12. 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.

  13. Equilibrium analysis of a sandstone roll-front uranium deposit

    International Nuclear Information System (INIS)

    The increasing demand for nuclear energy and the lower grades of mineralization being encountered in many areas have brought about the requirement for a detailed understanding of the distribution of equilibrium characteristics in uranium ore deposits. A roll-front type deposit located in a continental sandstone in northeastern Wyoming was studied and the distribution of the secular equilibrium was determined. The deposit was broken into six character classes and the equilibrium trait of each class was evaluated by several methods. The disequilibrium factors obtained during this study were combined with known geological features in the deposit, and equilibrium corrections were applied to preliminary mine planning and evaluation activities. The results of this study verify previous reports on other roll-front deposits. The altered portion was found to be depleted in uranium while the front and material on the unaltered side of the front were found to be enriched. The statistical and graphical methods of obtaining disequilibrium factors are presented. (author)

  14. Benefits of a horizontal well in sandstone waterflood

    International Nuclear Information System (INIS)

    This is a case study which describes the planning and results of a horizontal well in a shallow Wilcox sandstone waterflood unit in central Louisiana. The Tremont H-13-1 was OXY USA Inc.'s first horizontal well. Analysis will include examination of the selection criteria, planning, execution, completion, and production. A variety of well and field data is presented and reviewed to access the value of this information as it applies towards other applications. The Cruse Waterflood Unit is a 2100 ft. Wilcox formation in central Louisiana. Production improvements have been 500% or greater for the horizontal well versus adjacent vertical wells. The horizontal well paid out in less than 4 months Results from this well indicate that not only was this project an economic success, but that other fields will similar conditions can be produced in a more profitable manner with horizontal wells

  15. 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. PMID:16346858

  16. 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.

  17. 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.

  18. 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.

  19. 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

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  1. Offers for our members

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    Science.gov (United States)

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    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.

  4. Diagenesis: A short (2 million year) story -- Miocene sandstones of central Sumatra, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Gluyas, J. [BP Venezuela, Caracas (Venezuela); Oxtoby, N. [BP Exploration, Sunbury on Thames (United Kingdom)

    1995-07-03

    The Miocene Sihapas Formation sands of the Central Sumatra Basin (Indonesia) are being cemented by quartz, clay, and carbonate minerals, today. Precipitation of these minerals in the pore spaces has reduced the porosity of the sandstones from 30% to 20%. Four independent sets of data are interpreted to show that cementation began only 2 million years ago and that it is active today: (1) A major reverse fault split a once continuous Sihapas sandstone about two million years ago. In the hanging wall of the fault the Sihapas sand is uncemented. In the footwall the same sandstone is cemented. (2) Compaction-induced porosity loss in these sandstones is the same as that expected for the present burial depth of the sandstones. (3) The temperature at which quartz cement precipitated is the same as the present-day formation temperature. (4) Water trapped within fluid inclusions in the quartz cement is of similar low salinity to the formation water, and the oxygen isotopic composition of the quartz cement and modern formation water are approximately in equilibrium. These data for the Sihapas sandstone add to a growing body of evidence which indicates that cementation of sandstones can occur over geologically short periods of a few millions of years to a few tens of millions of years (Lee et al. 1985; Glassmann et al. 1989; Robinson and Gluyas 1992a).

  5. Diagenetic controls on porosity variations within an aeolian sandstone reservoir, borehole Kudu 9A-3

    International Nuclear Information System (INIS)

    Three boreholes, Kudu 9A-1, 9A-2 and 9A-3, were drilled approximately 125 km west of the Orange River mouth to test a gas-bearing structure of Barremian age. The reservoir interval comprises an upper unit of interbedded shallow marine sandstones, limestones and volcaniclastic mass flow deposits, and a lower non-marine unit of interbedded aeolian sandstones, basaltic lavas and volcaniclastic deposits. Despite the overall good poroperm characteristics of the aeolian sandstone and its apparent mineralogical homogeneity, as implied by a gamma ray trace, the core analysis results show an extreme variation in porosity and permeability values. In order to assist in reservoir quality prediction and to assess the regional prospectivity of the sandstone, it was necessary to explain these variations. The resuls of the study indicate that compositionally and texturally the sandstones are extremely homogeneous. It is concluded that the marked variation in the poroperm characteristics of the aeolian sandstones is a result of a relatively complex diagenesis. A fluctuating water table resulted in the formation of a pattern of calcite, anhydrite and quartz cements within an aeolian dune sandstone. 7 refs., 1 fig

  6. The Members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 130 Member States of the Agency as of 1 December 1999. The new Member since the last issue of the list (INFCIRC/2/52) is Angola. The dates on which the present 130 Member States became Members, and the state Honduras) 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 are given in an Attachment

  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.55) is the Republic of Botswana, which deposited the instrument of acceptance of the Statute on 20 March 2002. The Attachment hereto shows the dates on which the present 134 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

  8. 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

  9. The Members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 135 Member States of the Agency as of 19 March 2003. The new Member since the last issue of the list (INFCIRC/2/56) is the Republic of Honduras. The dates on which the present 135 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

  10. {sup 57}Fe Moessbauer and X-ray characterisation of sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Mulaba-Bafubiandi, A. F. [University of Johannesburg, Mineral Processing and Technology Research Centre, Department of Metallurgy, School of Mining, Metallurgy and Chemical Engineering, Faculty of Engineering and The Built Environment (South Africa); Waanders, F. B., E-mail: frans.waanders@nwu.ac.za [North West University, School of Chemical and Minerals Engineering (South Africa)

    2013-04-15

    Sandstones from the Free State province in South Africa have been mined and processed mainly by small scale and artisanal miners in the rural areas. In the present investigation basic fire proof and water absorption tests, X-ray and {gamma}-ray based characterisation techniques were used to study the sandstones. The collected samples were grouped according to their apparent colour in day light conditions and the elemental analysis showed the presence of a high amount of oxygen (>52%) and silicon (>38%) with Mn, Al, Fe and Ca as major elements in proportions related to the colour distribution of the various sandstones. The uniaxial compressive stress was found to be the highest (56 MPa) for the greyish sandstone and the lowest (8 MPa) for the white sandstone sample, also associated with the lowest (Al+Fe)/Si value of 0.082. The humidity test showed that the 6 % water absorption was lower than the recommended ASTM value of 8 %. The sandstone samples were also subjected to various high temperatures to simulate possible fire conditions and it was found that the non alteration of the mineral species might be one of the reasons why the sandstones are regarded as the most refractory amongst the building materials typically used. Moessbauer spectroscopy revealed that iron is present in all the sandstones, mainly as Fe{sup 3 + } with the black sandstone showing an additional presence of 3 % Fe{sup 2 + } indicating that a higher iron content coupled to higher silicon content, contributes to an increase in the uniaxial compressive strength.

  11. 57Fe Mössbauer and X-ray characterisation of sandstones

    International Nuclear Information System (INIS)

    Sandstones from the Free State province in South Africa have been mined and processed mainly by small scale and artisanal miners in the rural areas. In the present investigation basic fire proof and water absorption tests, X-ray and γ-ray based characterisation techniques were used to study the sandstones. The collected samples were grouped according to their apparent colour in day light conditions and the elemental analysis showed the presence of a high amount of oxygen (>52%) and silicon (>38%) with Mn, Al, Fe and Ca as major elements in proportions related to the colour distribution of the various sandstones. The uniaxial compressive stress was found to be the highest (56 MPa) for the greyish sandstone and the lowest (8 MPa) for the white sandstone sample, also associated with the lowest (Al+Fe)/Si value of 0.082. The humidity test showed that the 6 % water absorption was lower than the recommended ASTM value of 8 %. The sandstone samples were also subjected to various high temperatures to simulate possible fire conditions and it was found that the non alteration of the mineral species might be one of the reasons why the sandstones are regarded as the most refractory amongst the building materials typically used. Mössbauer spectroscopy revealed that iron is present in all the sandstones, mainly as Fe3 +  with the black sandstone showing an additional presence of 3 % Fe2 +  indicating that a higher iron content coupled to higher silicon content, contributes to an increase in the uniaxial compressive strength.

  12. 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.76) is Brunei Darussalam, which deposited its instrument of acceptance of the Statute on 18 February 2014. The Attachment hereto shows the dates on which the present 162 Member States deposited instruments of ratification or acceptance of the Statute with the depositary Government

  13. 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.68) is the Lao People's Democratic Republic which deposited its instrument of acceptance of the Statute on 4 November 2011. The Attachment hereto shows the dates on which the present 152 Member States deposited instruments of ratification or acceptance of the Statue with the depositary Government

  14. The members of the Agency

    International Nuclear Information System (INIS)

    The 42nd revision of INFCIRC/2 lists the 113 Member States of the International Atomic Energy Agency as of 1 January 1993. It includes Slovenia as a new Member State as of 21 September 1992, Cambodia replaces the former name ''Democratic Kampuchea'' and Czechoslovakia was deleted as it ceased to be a member of the Agency as of 1 January 1993 (INFCIRC/417)

  15. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Members since the last list of Member States was issued (INFCIRC/2/Rev.72) are Fiji and Togo, which deposited their instruments of acceptance of the Statute on 2 November 2012 and 1 November 2012, respectively. The Attachment hereto shows the dates on which the present 157 Member States deposited instruments of ratification or acceptance of the Statute with the depositary Government

  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.69) is the Commonwealth of Dominica, which deposited its instrument of acceptance of the Statute on 17 February 2012. The Attachment hereto shows the dates on which the present 153 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.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

  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.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

  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.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

  20. 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

  1. Study on geochronology of sandstone-type uranium mineralization in western Hailaer basin

    International Nuclear Information System (INIS)

    The study on U-Pb isotopic dating of sandstone-type uranium mineralization in western Hailaer basin, namely, Xihulitu and Kelulun depressions, has been carried out. The ages of 81 ± 2 Ma, 44 ± 2 Ma, 9 ± 2 Ma, 2 ± 0 Ma for sandstone-type uranium mineralization in Xihulitu depression and 51 ± 8 Ma, 67 ± 5 Ma for sandstone-type uranium mineralization in Kelulun depression have been obtained for the first time by U-Pb isochron dating. These mineralization ages are in good accordance with the tectonic and climatic evolution histories of the study area

  2. Modeling of stress-strain dependences for Berea sandstone under quasistatic loading

    Science.gov (United States)

    Vakhnenko, Vyacheslav O.; Vakhnenko, Oleksiy O.; Tencate, James A.; Shankland, Thomas J.

    2007-11-01

    In this work, a phenomenological model to describe the complex stress-strain properties of a sandstone sample under slow loading is presented. We consider a combination of three methods to treat the elastic and nonlinear behavior observed in stress cycling experiments. The mechanisms to treat interior equilibration processes in sandstone are termed the standard solid relaxation mechanism, the sticky-spring mechanism, and the permanent plastic deformation mechanism. With a small number of parameters, the overall model displays both qualitatively and quantitatively the principal experimental observations of the stress-strain trajectories for Berea sandstone, in particular, the details of end-point memory under quasistatic loading.

  3. Discussion on metallogenic prospect of sandstone-type uranium deposit in Yabulai basin

    International Nuclear Information System (INIS)

    Based on characteristics of initial basin type and tectonic reworking process, this article analyses the distribution features of depositional system and subsequent alteration of the target horizon of sandstone-type uranium deposits in Yabulai basin. Guided by prognostic criteria of sandstone-type uranium deposits, authors suggest that the post-depositional tectonic reworking in the basin was quite intense, and uranium metallogenic prospects are unfavorable. However, the Lower Cretaceous in the paleo-slope at the middle of the basin does show certain metallogenic prospects for sandstone-type uranium deposits

  4. 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.

  5. Abrasion resistant tubular member

    International Nuclear Information System (INIS)

    A surface of a tubular member made of an austenite stainless steel having a molybdenum content of from 2 to 3% is subjected to a low temperature ionization nitriding treatment in a gas atmosphere of N2: from 5 to 15% by volume, H2: from 95 to 85% by volume, at a temperature of from 400 to 470degC to form a nitride layer. Since the low temperature ion nitriding treatment is thus applied, generation of ε phase which lowers corrosion resistance can be suppressed. That is, the hardened layer (nitride layer) is provided with abrasion resistance, while the inside can keep the inherent characteristic of the austenite stainless steel having high toughness. In addition, this can avoid the tendency of lowering corrosion resistance due to the formation of a ε phase caused by exposure to high temperature for a long time in order to increase the thickness of the nitrided layer. When the thickness of the tube is 1.3mm, the less than 130μm is enough for the nitride layer. Abrasion resistance can be improved by thus applying ion nitriding treatment to the austenite stainless steel containing molybdenum under controlled temperature and atmosphere. (N.H.)

  6. 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.

  7. 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

  8. 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

  9. 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...

  10. Permeability and electrical conductivity changes due to hydrostatic stress cycling of Berea and Muddy J sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Dey, T.N.

    1986-01-10

    Cyclic loading affects the electrical conductivity and fluid permeability of kaolinite clay-bearing sandstone. The effective confining pressure on two sandstones was repeatedly raised and lowered between 3.5 and 31.5 MPa. Permeabilities dropped by 30% for Berea sandstone and 90% for Muddy J sandstone after thre cycles; however, total pore volume always returned to its initial value; after each cycle. Water salinity had little effect on these results. Electrical conductivity showed no change when a very conductive pore fluid, 1 M KC/water, was used, however the conductivity showed the same decreases as permeability when demineralized water was the pore fluid. These results show that clay particle rearrangement in the pores is probably responsible for the permeability changes.

  11. Permeability and electrical conductivity changes due to hydrostatic stress cycling of berea and muddy J sandstone

    Science.gov (United States)

    Dey, Thomas N.

    1986-01-01

    Cyclic loading affects the electrical conductivity and fluid permeability of kaolinite clay-bearing sandstone. The effective confining pressure on two sandstones was repeatedly raised and lowered between 3.5 and 31.5 MPa. Permeabilities dropped by 30% for Berea sandstone and 90% for Muddy J sandstone after three cycles; however, total pore volume always returned to its initial value after each cycle. Water salinity had little effect on these results. Electrical conductivity showed no change when a very conductive pore fluid, 1 M KCl water, was used, however the conductivity showed the same decreases as permeability when demineralized water was the pore fluid. These results show that clay particle rearrangement in the pores is probably responsible for the permeability changes.

  12. 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....

  13. 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.

  14. 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.

  15. 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.

  16. 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...... 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...

  17. 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...

  18. 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.

  19. The streaming potential of liquid carbon dioxide in Berea sandstone

    Science.gov (United States)

    Moore, Jeffrey R.; Glaser, Steven D.; Morrison, H. Frank; Hoversten, G. Michael

    2004-09-01

    We report here, for the first time, evolution of the streaming potential coupling coefficient as liquid carbon dioxide infiltrates Berea sandstone. Using 125 Ω-m tap water, the coupling coefficient determined before and after each CO2 flood of five samples averaged approximately -30 mV/0.1 MPa. After liquid CO2 passed through the specimens displacing all mobile pore water, trapped water remained and the coupling coefficient was approximately -3 mV/0.1 MPa. A bound water limit of the coupling coefficient for liquid CO2 flow was found using an air-dried sample to be -0.02 mV/0.1 MPa. For initially water-saturated samples, bulk resistivity varied during CO2 invasion from 330 Ω-m, to 150 Ω-m during CO2/water mixing, to a final value of 380 Ω-m. Results suggest that trapped and bound water control electrical conduction and the electrokinetic response. Applications include monitoring CO2 injectate in subsurface reservoirs using the self potential method.

  20. Slow dynamics in the nonlinear elastic response of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ten Cate, J.A.; Shankland, T.J. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

    1996-10-01

    A typical resonance curve{emdash}measured acceleration versus drive frequency{emdash}made on a thin bar of rock shows peak bending with a softening (nonlinear) modulus as drive levels are increased. The shapes of these nonlinear resonance curves were found in earlier work to depend somewhat on sweep rate; these {open_quote}{open_quote}slow dynamics{close_quote}{close_quote} are now examined and quantified. We have measured slow dynamics in a 0.3 m long, 50 mm diameter bar of Berea sandstone under ambient conditions. Peak strain levels during the experiments ranged from 10{sup {minus}11} to 10{sup {minus}5} at driving frequencies near 4 kHz, the fundamental longitudinal resonance frequency of the bar. Slow dynamics begin to manifest themselves at strain amplitudes above 10{sup {minus}6} at ambient conditions and at the onset of nonlinear peak bending. Strains above this value condition the rock, altering its response for minutes to hours after the drive has been turned off. {copyright} American Geophysical Union 1996

  1. Influence of texture on steady foam flow in Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ettinger, R.A.; Radke, C.J. (Univ. of California (US))

    1992-02-01

    Foam shows great promise as a fluid for improving mobility control in EOR process. An understanding of texture, or bubble-size, evolution is paramount for modeling foam flow in porous media in that fine textures may impart large flow resistances. Bubble-size, in turn, is determined by complicated lamella creation and decay processes. In this paper, the authors report for the first time, the quantitative role of bubble size in the steady flow of strong foam through a 0.8-{mu}m{sup 2} Berea sandstone. Inlet and outlet textures are determined from photomicrographs taken of bubbles flowing through specially designed visual cells. Concurrent measurements of pressure and liquid-saturation profiles by microwave attenuation are acquired for gas velocities from 1 to 3 m/d and foam qualities from 70% to 90%. A simple, 1D foam population-balance model is outlined to quantify the observed flow and texture behavior. Agreement between the proposed model and the new bubble-size and flow data is adequate. The population-balance method proves to be a useful tool.

  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. 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).

  4. Lithostratigraphy of the Old Red Sandstone successions of the Anglo-Welsh Basin

    OpenAIRE

    Barclay, W.J.; Davies, J.R.; Hillier, R.D.; Waters, R.A.

    2015-01-01

    This report presents a revised lithostratigraphy of the Old Red Sandstone of the Anglo-Welsh Basin, prepared under the auspices of the British Geological Survey (BGS) Stratigraphical Framework Committee (SFC). The report provides a correlation of the successions in different parts of the basin and rationalises group and formation nomenclature for the outcrops of Old Red Sandstone in England and Wales. It is based on a previous discussion document (Barclay, unpublished MS, 2007) which presente...

  5. 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, ...

  6. Effect of Sterilization by Dry Heat or Autoclaving on Bacterial Penetration through Berea Sandstone

    OpenAIRE

    Jenneman, Gary E.; McInerney, Michael J.; Crocker, Michael E.; Knapp, Roy 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°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 ...

  7. 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.

  8. Origin of regular cavities in European sandstones: field evidence for dissolution of carbonate and silica cement

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří; Mikuláš, Radek; Mertlík, J.

    Wrocław : Instytut Geografii i Rozwoju Regionalnego Uniwersytetu Wrocławskiego, 2013 - (Migoń, P.; Kasprzak, M.), s. 13-18 ISBN 978-83-62673-29-2. [Sandstone Landscapes (3.). Kudowa-Zdrój (PL), 25.04.2012-28.04.2012] R&D Projects: GA AV ČR IAA300130806 Institutional support: RVO:67985831 Keywords : sandstones * origin of cavities Subject RIV: DB - Geology ; Mineralogy

  9. 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...

  10. 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)

  11. Characteristics and model of sandstone type uranium deposit in south of Songliao basin

    International Nuclear Information System (INIS)

    Through analyzing the uranium deposit tectonic environment, upper cretaceous sequence stratigraphy, depositional system, evolutionary characteristics of sand bodies, the effect of subsequent transformation and the characteristic of uranium deposit, the sandstone type uranium deposit in southern basin is different from typical interlayer oxidation zone sandstone type uranium deposit. The formation and evolution of sandstone-type uranium deposit are controlled by structure fensters; the favorable sedimentary facies type is braided river facies, and the ore body is braided river sand body. The size of uranium deposits is controlled by the local oxidation zone with the characteristics of sandstone type uranium deposit in partial oxidation zone. Uranium ore bodies which distribute in the roof wings of structure fenstes, and occur in gray layers between the upper and lower oxidation zone, showing tabular, and the plate of uranium ore body is controlled by the local oxidation zone. Based on the geological features of sandstone-type uranium deposits, the metallogenic model of local oxidation zones sandstone-type uranium deposits has been set up in the south of Songliao Baisn. (authors)

  12. Developing conceptual hydrogeological model for Potsdam sandstones in southwestern Quebec, Canada

    Science.gov (United States)

    Nastev, Miroslav; Morin, R.; Godin, Rejean; Rouleau, Alain

    2008-01-01

    A hydrogeological study was conducted in Potsdam sandstones on the international border between Canada (Quebec) and the USA (New York). Two sandstone formations, arkose and conglomerate (base) and well-cemented quartz arenite (upper), underlie the study area and form the major regional aquifer unit. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously overlie the aquifer. In both sandstone formations, sub-horizontal bedding planes are ubiquitous and display significant hydraulic conductivities that are orders of magnitude more permeable than the intact rock matrix. Aquifer tests demonstrate that the two formations have similar bulk hydrologic properties, with average hydraulic conductivities ranging from 2 ?? 10-5 to 4 ?? 10-5 m/s. However, due to their different lithologic and structural characteristics, these two sandstones impose rather different controls on groundwater flow patterns in the study area. Flow is sustained through two types of fracture networks: sub-horizontal, laterally extensive fractures in the basal sandstone, where hydraulic connectivity is very good horizontally but very poor vertically and each of the water-bearing bedding planes can be considered as a separate planar two-dimensional aquifer unit; and the more fractured and vertically jointed system found in the upper sandstone that promotes a more dispersed, three-dimensional movement of groundwater. ?? Springer-Verlag 2007.

  13. 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.

  14. The Members of the Agency

    International Nuclear Information System (INIS)

    The new Members since the last list of Member States was issued (INFCIRC/2/Rev.75) are San Marino and the Bahamas, which deposited their instruments of acceptance of the Statute on 25 November 2013 and 7 January 2014, respectively. The Attachment hereto shows the dates on which the present 161 Member States deposited instruments of ratification or acceptance of the Statute with the depositary Government

  15. The Members of the Agency

    International Nuclear Information System (INIS)

    The new member since the last list of Member States of the Agency was issued (INFCIRC/2/Rev.44) is Yemen. The Attachment hereto shows the dates on which the 122 States became members of the Agency, as well as the State whose application for membership of the Agency was approved by the General Conference, but which has not yet deposited an instrument of acceptance of the Statute

  16. The Members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 129 Member States of the Agency as of 1 June 1999. The new Member since the last issue of the list (INFCIRC/2/51) is Benin. The dates on which the present 129 states became Members, and the state (Honduras) whose application for membership of the Agency has been recommended by the Board of Governors to be considered at the 43rd session of the General Conference are given in an Attachment

  17. 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

  18. 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

  19. 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

  20. 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.46) is Bosnia and Herzegovina. The Attachment hereto shows the dates on which the present 123 Member States became Members. It also shows the States whose applications for membership of the Agency have been approved by the General Conference but which have not yet deposited an instrument of acceptance of the Statute and the State whose application for membership has been recommended by the Board of Governors for approval by the General Conference

  1. The members of the Agency

    International Nuclear Information System (INIS)

    The document lists the 124 Member States of the Agency as of 1 September 1996. The new Member since the last issue of the list (INFCIRC/2/Rev.47) is Georgia. In an attachment are given the dates on which the 124 Member States became Members, the State (Latvia) 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 State (Republic of Moldova) whose application for membership has been recommended by the Board of Governors for approval by the General Conference

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

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

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Laboratory-determined transport properties of Berea sandstone

    International Nuclear Information System (INIS)

    The authors report laboratory measurements of electrical resistivity water permeability k, and compressional wave velocity V/sub p/ for both intact and fractured Berea sandstone samples as functions of temperature from 20 C to 200 C and effective pressure P/sub e/ from 2.5 MPa to 50 MPa. For the intact sample, V/sub p/ increases from 3.52 km/s to 4.16 km/s as P/sub e/ goes from 3 to 50 MPa. With increasing temperature, V/sub p/ decreases at rates of about 3% per 100 C at P/sub e/ of 5 MPa and about 1.5% per 100 C at P/sub e/ of 38 MPa. Data from the fractured sample are qualitatively similar, but velocities are about 10% lower. For both intact and fractured samples, p increases less than 15% as P/sub e/ increases from 2.5 MPa to 50 MPa. Although both samples show a larger decrease in resistivity with increasing temperature, most of this change is attributed to the decrease in resistivity of the pore fluid over that temperature range. For both samples, k decreases with increasing pressure and temperature. The intact sample permeability varies from 23 mD at 3 MPa and 20 C to less than 1 mD at 50 MPa and 150 C. The permeability of the fractured sample varies from 676 mD at 3 MPa and 20 C to less than 1 mD at 40 MPa and 190 C. The effect of the fracture on k vanishes after several pressure cycles and above about 100 C. These laboratory data are used to demonstrate the possibility of using resistivity and velocity measurements to estimate in-situ permeability of a reservoir. 25 references, 10 figures

  10. Micromechanics of brittle faulting and cataclastic flow in Berea sandstone

    Science.gov (United States)

    Menéndez, Beatriz; Zhu, Wenlu; Wong, Teng-Fong

    1996-01-01

    The micromechanics of failure in Berea sandstone were investigated by characterizing quantitatively the evolution of damage under the optical and scanning electron microscopes. Three series of triaxial compression experiments were conducted at the fixed pore pressure of 10 MPa and confining pressures of 20, 50 and 260 MPa, respectively, corresponding to three different failure modes: shear localization with positive dilatancy, shear localization with relatively little dilatancy and distributed cataclastic flow. To distinguish the effect of non-hydrostatic stress from that of hydrostatic pressure, a fourth suite of hydrostatically loaded samples was also studied. Using stereological procedures, we characterized quantitatively the following damage parameters: microcrack density and its anisotropy, pore-size distribution, comminuted volume fraction and mineral damage index. In the brittle regime, shear localization did not develop until the post-failure stage, after the peak stress had been attained. The microcrack density data show that very little intragranular cracking occurred before the peak stress was attained. We infer that dilatancy and acoustic emission activity in the prefailure stage are primarily due to intergranular cracking, probably related to the shear rupture of lithified and cemented grain contacts. Near the peak stress, intragranular cracking initiates from grain contacts and this type of Hertzian fracture first develops in isolated clusters, and their subsequent coalescence results in shear localization in the post-failure stage. The very high density of intragranular microcracking and pronounced stress-induced anisotropy in the post-failure samples are the consequence of shear localization and compactive processes operative inside the shear band. In contrast, Hertzian fracture was a primary cause for shear-enhanced compaction and strain hardening throughout the cataclastic flow regime. Grain crushing and pore collapse seem to be most intense in

  11. Laboratory-determined transport properties of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Daily, W.D.; Lin, W.

    1985-05-01

    The authors report laboratory measurements of electrical resistivity water permeability k, and compressional wave velocity V/sub p/ for both intact and fractured Berea sandstone samples as functions of temperature from 20 C to 200 C and effective pressure P/sub e/ from 2.5 MPa to 50 MPa. For the intact sample, V/sub p/ increases from 3.52 km/s to 4.16 km/s as P/sub e/ goes from 3 to 50 MPa. With increasing temperature, V/sub p/ decreases at rates of about 3% per 100 C at P/sub e/ of 5 MPa and about 1.5% per 100 C at P/sub e/ of 38 MPa. Data from the fractured sample are qualitatively similar, but velocities are about 10% lower. For both intact and fractured samples, p increases less than 15% as P/sub e/ increases from 2.5 MPa to 50 MPa. Although both samples show a larger decrease in resistivity with increasing temperature, most of this change is attributed to the decrease in resistivity of the pore fluid over that temperature range. For both samples, k decreases with increasing pressure and temperature. The intact sample permeability varies from 23 mD at 3 MPa and 20 C to less than 1 mD at 50 MPa and 150 C. The permeability of the fractured sample varies from 676 mD at 3 MPa and 20 C to less than 1 mD at 40 MPa and 190 C. The effect of the fracture on k vanishes after several pressure cycles and above about 100 C. These laboratory data are used to demonstrate the possibility of using resistivity and velocity measurements to estimate in-situ permeability of a reservoir. 25 references, 10 figures.

  12. 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

  13. TOUGHREACT Testing in High Ionic Strength Brine Sandstone Systems

    International Nuclear Information System (INIS)

    Deep saline formations and oil and gas reservoirs often contain concentrated brine solutions of ionic strength greater than 1 (I > 1 M). Geochemical modeling, involving high ionic strength brines, is a challenge. In the original TOUGHREACT code (Xu et al., 2004; Xu et al., 2006), activity coefficients of charged aqueous species are computed using an extended Debye-Huckel (DH) equation and parameters derived by Helgeson et al. (1981). The DH model can deal with ionic strengths from dilute to moderately saline water (up to 6 molal for an NaCl-dominant solution). The equations implemented for the DH model are presented in Appendix A. During the course of the Yucca Mountain project, a Pitzer ion-interaction model was implemented into TOUGHREACT. This allows the application of this simulator to problems involving much more concentrated aqueous solutions, such as those involving geochemical processes in and around high-level nuclear waste repositories where fluid evaporation and/or boiling is expected to occur (Zhang et al., 2007). The Pitzer ion-interaction model, which we refer to as the Pitzer virial approach, and associated ion-interaction parameters have been applied successfully to study non-ideal concentrated aqueous solutions. The formulation of the Pitzer model is presented in Appendix B; detailed information can be founded in Zhang et al. (2007). For CO2 geological sequestration, the Pitzer ion-interaction model for highly concentrated brines was incorporated into TOUGHREACT/ECO2N, then was tested and compared with a previously implemented extended Debye-Hueckel (DH) ion activity model. The comparison was made through a batch geochemical system using a Gulf Coast sandstone saline formation

  14. Personality characteristics of Wikipedia members.

    Science.gov (United States)

    Amichai-Hamburger, Yair; Lamdan, Naama; Madiel, Rinat; Hayat, Tsahi

    2008-12-01

    Wikipedia is an online, free access, volunteer-contributed encyclopedia. This article focuses on the Wikipedians' (Wikipedia users) personality characteristics, studying Wikipedians' conceptions of Real-Me and BFI dimensions. To survey these aspects, we posted links to two online web questionnaires; one was targeted at Wikipedians and the second to non-Wikipedia users. One hundred and thirty-nine subjects participated in the study, of which 69 were active Wikipedia members. It was found that Wikipedia members locate their real me on the Internet more frequently as compared to non-Wikipedia members. Variance analysis revealed significant differences between Wikipedia members and non-Wikipedia members in agreeableness, openness, and conscientiousness, which were lower for the Wikipedia members. An interaction was found between Wikipedia membership and gender: introverted women were more likely to be Wikipedia members as compared with extroverted women. The results of this study are discussed with special emphasis on the understanding of the motivators of Wikipedia members. PMID:18954273

  15. 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)

  16. 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

    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......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. The......, 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...

  17. 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.

  18. 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.

  19. 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

  20. Relationships among low frequency (2 Hz) electrical resistivity, porosity, clay content and permeability in reservoir sandstones

    Science.gov (United States)

    Han, Tongcheng; Best, Angus I.; Sothcott, Jeremy; North, Laurence J.; MacGregor, Lucy M.

    2015-01-01

    The improved interpretation of marine controlled source electromagnetic (CSEM) data requires knowledge of the inter-relationships between reservoir parameters and low frequency electrical resistivity. Hence, the electrical resistivities of 67 brine (35 g/l) saturated sandstone samples with a range of petrophysical properties (porosity from 2% to 29%, permeability from 0.0001 mD to 997.49 mD and volumetric clay content from 0 to 28%) were measured in the laboratory at a frequency of 2 Hz using a four-electrode circumferential resistivity method with an accuracy of ± 2%. The results show that sandstones with porosity higher than 9% and volumetric clay content up to 22% behave like clean sandstones and follow Archie's law for a brine concentration of 35 g/l. By contrast, at this brine salinity, sandstones with porosity less than 9% and volumetric clay content above 10% behave like shaly sandstones with non-negligible grain surface conductivity. A negative, linear correlation was found between electrical resistivity and hydraulic permeability on a logarithmic scale. We also found good agreement between our experimental results and a clay pore blocking model based on pore-filling and load-bearing clay in a sand/clay mixture, variable (non-clay) cement fraction and a shaly sandstone resistivity model. The model results indicate a general transition in shaly sandstones from clay-controlled resistivity to sand-controlled resistivity at about 9% porosity. At such high brine concentrations, no discernible clay conduction effect was observed above 9% porosity.

  1. 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.

  2. What is the relationship between vegetation in sandstone deep valley and basic measured microclimatic parameters in the Bohemian Switzerland

    Czech Academy of Sciences Publication Activity Database

    Zmeškalová, Jana; Wild, Jan

    Wroclaw : Uniwersytet Wroclawski, 2013 - (Migoń, P.; Kasprzak, M.), s. 232-234 ISBN 978-83-62673-29-2. [Sandstone Landscapes. Diversity, Ecology and Conservation. 3rd International Conference on Sandstone Landscapes. Kudowa-Zdrój (PL), 25.08.2012-28.08.2012] R&D Projects: GA TA ČR TA01021283 Institutional support: RVO:67985939 Keywords : microclimate * vegetation * sandstone landscape Subject RIV: EF - Botanics

  3. Reservoir quality of deeply buried, Upper Jurassic sandstones of the South Viking Graben : A sedimentological, petrophysical and modeling approach

    OpenAIRE

    2008-01-01

    Quartz cement, precipitated as syntaxial overgrowths on detrital quartz grains, is the dominant porosity-destroying process in deeply buried quartz-rich sandstones and has proven to be predominantly a pressure insensitive, precipitation rate controlled process in North-Sea reservoir sandstones. Grain-coats are the most important porosity-preserving mechanism in North-Sea sandstones buried to great depths (>4km), because they cover detrital quartz surfaces and thus block precipitation of synta...

  4. 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.43) are: Kazakhstan and the former Yugoslav Republic of Macedonia. The Democratic People's Republic of Korea withdrew from membership of the Agency as of 13 June 1994. The Attachment hereto shows the dates on which the 121 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

  5. 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

  6. 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.

  7. 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.

  8. 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)

  9. 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

  10. The Berea Sandstone -- a shallow, low permeable gas reservoir in Dickenson County, Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Nolde, J.E. (Virginia Dept. of Mines, Minerals and Energy, Charlottesville, VA (United States))

    The Berea Sandstone is a major resource of natural gas in a low permeability, low pressure reservoir at depths of less than 5,000 feet in Dickenson County. The sandstone lies between the underlying Devonian shale sequence and the overlying Sunbury Shale. Thickness of the Berea ranges from 20 to 150 feet. Gas associated with the Berea is the product of the immature stage of hydrocarbon generation (biogenic gas). Trend surface analysis of thickness data delineates a prominent nearshore bar complex and associated facies extending northerly across the central-portion of the county. These nearshore marine bar sediments are cut locally by shallow marine channel deposits of the Virginia-Carolina delta. The marine bar facies is a coarsening-upward sequence consisting of very-fine-grained sandstone. The channel facies grades upward from medium-to percent, with permeabilities of 0.003-0.008 millidarcies.

  11. Reviews on the metallogenic and geological features of sandstone-type uranium deposits in Japan

    International Nuclear Information System (INIS)

    Regional geologic settings of sandstone-type uranium deposits in Japan are firstly analyzed. The regional tectonic evolution characteristics of 'Green tuff region' and 'Non green tuff region' and their relationship with uranium mineralization are elaborated in depth. Based on those mentioned above, the uranium sources of sandstone-type uranium deposits in Japan are discussed deeply and the most favorable uranium sources are considered to come from the basement and the surrounding granites. Their intrusive epochs range from Later Cretaceous to Palaeogene (about 60 to 70 Ma ago). The characteristics of ore-bearing host rocks, matter compositions of the deposits, ore formation enrichment factors, the hydrogeologic conditions and so on are described by taking Ningyo-Toge and Tono deposits as examples. Finally, the prospecting measures for the palaeo-channel sandstone-type uranium deposits (basal type) are reviewed. (authors)

  12. Variation of wave velocity and porosity of sandstone after high temperature heating

    Science.gov (United States)

    Sun, Qiang; Zhang, ·Weiqiang; Su, Tianming; Zhu, Shuyun

    2016-05-01

    This paper reports the variations of mass, porosity, and wave velocity of sandstone after high temperature heating. The range of temperature to which the sandstone specimens have been exposed is 25-850°C, in a heating furnace. It has been shown that below 300°C, porosity and wave velocity change very little. Above 300°C, there is a rapid increase in porosity, but the wave velocity decreases significantly. The results of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and mercury intrusion porosimetry (MIP) suggest that a series of changes occurred between 400 and 600°C in sandstone could be responsible for the different patterns of variation in porosity and wave velocity.

  13. 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)

  14. Chemostratigraphy of the Silurian Qusaiba Member, Eastern Saudi Arabia

    Science.gov (United States)

    Craigie, Neil W.

    2016-01-01

    Given the unavailability of high resolution biostratigraphic data and difficulties in using lithostratigraphy for stratigraphic correlation, it was decided to employ chemostratigraphy to propose a scheme for the Silurian Qusaiba Member encountered in five wells in Eastern Saudi Arabia. Chemostratigraphy may be defined as a reservoir correlation technique involving the utilization of inorganic geochemical data. Although Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) were used to acquire data for 50 elements, the scheme is based on changes in the following 'key' element ratios: Zr/Th, Cr/Ti, Th/Nb, Zr/P, Y/Yb, Zr/Yb and Y/P. Variations in these parameters are largely dependent on changes in source/provenance, reflecting increases or decreases in the abundances of particular detrital heavy minerals. The scheme comprises a hierarchical order of four zones, seven subzones and four divisions. The zones are labelled C1, C2, C3 and C4 is ascending stratigraphic order, with two, three and two subzones identified in C2, C3 and C4 respectively. In addition to this, chemostratigraphic divisions are noted in two of the subzones. The chemostratigraphic scheme is considered robust as chemozones (general term used to describe any zone, subzone or division) are clearly defined in each well using geochemical profiles and binary diagrams plotted for key element ratios. Furthermore, high levels of statistical confidence are associated with the chemozones and most are correlative between three or more wells. The nonexistence of chemozones in particular wells is mainly explained by the sampling strategy employed. For example, the absence of subzone C3-2 (occurring towards the center of zone C3) in wells 4 and 5 is most likely to be explained by the uppermost part of the Qusaiba Member not being sampled. In other instances, particular chemozones may be missing as a result of erosion/non-deposition on a

  15. 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

  16. Pore geometry of Berea sandstone and numerical simulation of fluid flow by LBM under pressurization

    Science.gov (United States)

    Takahashi, M.; Sato, M.

    2012-12-01

    The Berea sandstone has a clear bedding plane and not clear cross lamina in cm size specimen, which is mainly caused by grain orientation and void space in microscopic scale. During the confined triaxial compression test, we measured permeability of Berea sandstone by constant head test for three mutually perpendicular directions under effective confining pressure and increasing differential axial stress. In general, the permeability of Berea sandstones decreased slightly with increasing the effective confining pressure and axial differential stress. Permeability anisotropy was also observed in the normal and two parallel directions to the bedding planes. We introduced the three-dimensional medial axis (3DMA) method of Lindquist et al. (2000) to quantify the flow-relevant geometric properties of the voids structure in Berea sandstone. Using these data, we also evaluated the number of connecting path between two faces, tortuosity and the shortest path distribution within an arbitrary region of Berea sandstone specimen. Geometrical information on the number of connecting path in an arbitrary volume CT data shows reasonable correlation between permeability anisotropy and mutually perpendicular directions normal and parallel to bedding planes. In addition, we introduced numerical simulation of fluid flow of pressurized Berea sandstone by LBM, to discuss the permeability reduction caused by pressurization. We obtained the detail distributions of fluid pressure, fluid velocity and its vector distribution in rather narrow voids space more than 10 μm. It is confirmed that pressurization caused decrease of the connecting path and the shortest path between arbitrary faces, and then caused a complex condition of on fluid pressure and fluid velocity.

  17. 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

  18. Computer mapping and prospect evaluation of Berea Sandstone and Clinton sandstone interval in northeastern Ohio using Radian's CPS/PC mapping software

    Energy Technology Data Exchange (ETDEWEB)

    Urian, B.A.

    1988-08-01

    Radian's CPS/PC mapping package and a standard IMB AT were used to map and evaluate producing zones in the Berea Sandstone and the Clinton sandstone section. Radian's CPS/PC software has several features in addition to computer mapping that help with prospect evaluation. A windowing feature allows any portion of the map to be enlarged for a more detailed view. Radian's Grid Editor allows the user to move and bias the contour lines to fit a specific geologic interpretation. A volumetric option calculates volumetric reserves of irregularly shaped reservoirs based on the mapped shape of the reservoir. In this study, Lotus 1-2-3 was used for data base management.

  19. 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.

  20. 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...

  1. Hydrocarbon accumulations of Mississippian Berea sandstone in west-central West Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Cox, D.L. (Peake Energy, Inc., Ravenswood, WV (USA))

    1988-08-01

    The Berea Sandstone is a widely recognized producer of oil and gas in the Appalachian basin. Subsurface mapping, core analysis, and production data from producing wells have been evaluated in west-central West Virginia, where the Berea Sandstone represents a wide range of nearshore and coastal environments. Fluvial system deposits are found in southern Jackson County as channel sands (Gay-Fink) and adjacent deltaic facies. Coastal sediments were deposited to the north as intertidal shoals, tidal flats, and coarse-grained tidal-creek point bars. Marine shelf sands are found to the west.

  2. Structural controls of shihongtan sandstone-type uranium deposit in the southwestern turpan-hami basin

    International Nuclear Information System (INIS)

    Through studying the structural evolution, structural characteristics of Shihongtan sandstone-type uranium deposit, it is found that there are three types of structural controls on Shihongtan sandstone-type uranium deposit on the Aiding structural slope, namely, the uranium sources, types of the sedimentary formation of target horizons and the mineralization epochs are controlled by the structural evolution of the basin; the mineralization area are controlled by the structural slope units; the distribution of uranium ore bodies is controlled by the second order structures on the structural slope. (authors)

  3. 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

  4. 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...

  5. COMPOSITION AND PROVENANCE OF GRÖDEN SANDSTONE FROM THE VELEBIT MTS.

    OpenAIRE

    Vedran Sudar; Dunja Aljinović; Duje Smirčić; Uroš Barudžija

    2016-01-01

    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 sample...

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. Method for determination of clay and mica consentrations in underground sandstone formations by radioactivity logging

    International Nuclear Information System (INIS)

    An underground formation is logged for the registration of natural gamma radiation from trace amounts of thorium, uranium and potassium. Both the clay and mica content for an interesting interval is determined from natural gamma activities in the interval of interest, in a pure sandstone interval and in a shale interval free from mica

  11. Laboratory Measurement of Curie’s Temperature for Sandstone from Ewekoro, Nigeria

    Directory of Open Access Journals (Sweden)

    Olorode, D. O.

    2014-04-01

    Full Text Available One of the factors affecting attenuation of seismic waves is anelasticity – the departure from ideal elastic behavior in the interior of the Earth. Studies of the anelasticity of the Earth had begun in Nigeria by seismologists using various techniques at room temperature, to investigate what could be responsible for the mechanism. Continuous-wave transmission and spectral amplitude wave-ratio techniques were employed in this study to investigate the effects of temperature on sandstone from the upper crust. The frequency range 10HZ to 1000Hz were investigated. The aim is to obtain Curie’s Temperature of Ewekoro sandstone which can serve as a parameter for mineral identification. A special kiln was constructed to heat the rock sample from 344K to 774k. Results obtained show that attenuation is affected by many mechanisms including presence of organic matter, seashells and presence of impurities or hydrocarbons in the rock matrix. There is a general increase in the attenuation of the rock sample when heated this is attributable to the thermal agitation of the internal constituents in the rock matrix, causing annealing in it. The Attenuation versus temperature curve of sandstone has a peak at 630 K, which is the observed Curie’s temperature for sandstone.

  12. Spherical and ellipsoidal cavities in European sandstones: a product of sinking carbonate dissolution front

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří; Mikuláš, Radek; Navrátil, Tomáš

    2015-01-01

    Roč. 59, Supplement 1 (2015), s. 123-149. ISSN 0372-8854 R&D Projects: GA AV ČR IAA300130806; GA ČR GA13-28040S Institutional support: RVO:67985831 Keywords : symmetrical cavities * solutional landforms * cavernous weathering * tafoni * sandstone * concretions * carbonate dissolution front Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.734, year: 2014

  13. Sensibility test for uranium ores from Qianjiadian sandstone type uranium deposit

    International Nuclear Information System (INIS)

    Sensibility tests for uranium ores from Qianjiadian sandstone type uranium deposit in Songliao Basin which is suitable to in-situ leach are carried out, including water sensibility, velocity sensibility, salt sensibility, acid sensibility and alkaline sensibility. The sensibility critical value of this ore is determined. Some references on mining process and technical parameter are provided for in-situ leaching of uranium. (authors)

  14. Spiders on sandstone rocks in Central Europe with particular reference to the Bohemian Switzerland National Park

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil

    Praha : Academia, 2007 - (Hartel, H.; Cílek, V.; Herben, T.; Jackson, A.; Williams, R.), s. 143-147 ISBN 978-80-200-1577-8 Institutional research plan: CEZ:AV0Z50070508 Keywords : spiders * Araneae * sandstone Subject RIV: EG - Zoology

  15. 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.

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

    OpenAIRE

    Chang, Philip Lee; Yen, Teh Fu

    1985-01-01

    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.

  17. 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. PMID:16346956

  18. Structure and fluid evolution of Yili basin and their relation to sandstone type uranium mineralization

    International Nuclear Information System (INIS)

    Based on the summary of strata and structure distribution of Yili basin, the relation of structure and fluid evolution to sandstone type ur alum mineraliation are analyzed. It is found that uranium mineralization in Yili basin experienced ore hosting space forming, pre-alteration of hosting space, hosting space alteration and uranium formation stages. (authors)

  19. Prospect analysis for sandstone-type uranium mineralization in the northern margin of Qaidam basin

    International Nuclear Information System (INIS)

    Affected by the regional geological structural evolution, a set of sedimentary structure, i.e. the construction of coal-bearing classic rocks which is in favor of the sandstone-type uranium mineralization has deposited in the northern margin of Qaidam Basin since Meso-Cenozoic. A NWW thrust nappe tectonic belt, i.e. the ancient tectonic belt which is the basis for the development of ancient interlayer oxidation zone formed by the tectonic reverse in late Jurassic and Cretaceous. The Mid and late Jurassic layer was buried by the weak extension in Paleogene and the depression in early Neogene. The extrusion reversal from late Neogene to Quaternary made the basin into the development era of the modern interlayer oxidation zone. It can be concluded that the layer of the northern margin of Qaidam Basin has the premise for the formation of sandstone-type uranium ore. Based on the analysis of the characteristics of the thrust belt, the structure of the purpose layer, the sand body, the hydrogeology, the interlayer oxidation zone and uranium mineralization, the results indicated that the ancient interlayer oxidation zone is the prospecting type of sandstone-type uranium ore. Beidatan and the east of Yuqia are the favorable prospective area of sandstone-type uranium mineralization. (authors)

  20. Application research on remote sensing geology of sandstone-type uranium deposit in Yili basin

    International Nuclear Information System (INIS)

    Based on remote sensing images and practical materials, and new ideas of laying particular emphasis on the research of regional geologic structures, and large in-situ leachable sandstone-type uranium deposits, applying the theory of plate tectonics, the author makes a comprehensive analysis on the uranium metallogenic environments, characteristics of regional geologic structures, the ore-controlling mechanism and factors, and uranium metallogeny. Authors propose that large interlayer oxidation zone sandstone-type uranium deposits are controlled by the combination of the stable block in Meso-Cenozoic compressive-shearing faulted subsided basin on the Yili multiphase massif in Tianshan paleo-island arc system, and the specific paleo-geographic environments and its' structural terrace'. The origin of hydrogenic sandstone-type uranium deposits is summarized by the authors as the 'mixing and neutralization' genetic model, and the 'eight ore-controlling factors merge into an organic whole' prospecting model. The above mentioned provides clear prospecting direction and new ideas for the forecasting direction for prospecting large sandstone-type uranium deposits

  1. Sandstone Districts of the Bohemian Paradise: Emergence of a Romantic Landscape

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří; Mikuláš, Radek; Cílek, Václav

    2006-01-01

    Roč. 21, - (2006), s. 6-99. ISSN 1210-9606 R&D Projects: GA AV ČR IAA3013302 Institutional research plan: CEZ:AV0Z30130516 Keywords : sandstone * rock city * Bohemian Paradise (Czech Republic) Subject RIV: DB - Geology ; Mineralogy http://geolines.gli.cas.cz/index.php?id=volume21

  2. Lithological controls on sandstone weathering: a proposal of morphofacies for the humid temperate zone of Europe

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří; Mikuláš, Radek; Schweigstillová, Jana

    Dresden : Höhlen- und Karstforschung Dresden e. V, 2010 - (Simmert, H.). s. 26-28 [Symposium on Pseudokarst /11./. 12.05.2010-16.05.2010, Saupsdorf/Saxon Switzerland] R&D Projects: GA AV ČR IAA300130806 Institutional research plan: CEZ:AV0Z30130516 Keywords : sandstone * morphofaciel * lithology Subject RIV: DB - Geology ; Mineralogy

  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. Composition of weathering crusts on sandstones from natural outcrops and architectonic elements in an urban environment.

    Science.gov (United States)

    Marszałek, Mariola; Alexandrowicz, Zofia; Rzepa, Grzegorz

    2014-12-01

    This work presents mineralogical and chemical characteristics of weathering crusts developed on sandstones exposed to various air pollution conditions. The samples have been collected from sandstone tors in the Carpathian Foothill and from buildings in Kraków. It has been stated that these crusts differ in both fabric and composition. The sandstone black crust from tors is rich in organic matter and composed of amorphous silica. Sulphate incrustations accompanied by dust particles have been only sometimes observed. Beneath the black crust, a zone coloured by iron (oxyhydr)oxides occurs. The enrichment of the surface crust in silica and iron compounds protects the rock interior from atmospheric impact. The sandstones from architectonic details are also covered by a thin carbon-rich black crust, but they are visibly loosened. Numerous salts, mainly gypsum and halite, crystallise here, thus enhancing deterioration of the rock. Moreover, spherical particles originated from industrial emissions are much more common. Gypsum in natural outcrops, forms isolated and well-developed crystals, whilst these found on the architectonic details are finer and densely cover the surface. Such diversity reflects various concentrations of acid air pollutants in solutions. PMID:25037099

  5. 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.

  6. Petrography and Diagenesis of Palaeocene -Eocene Sandstones in the Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari

       Glaconitic sandstones reservoir in the Siri Canyon are the basis for the investigatation of the geochemical composition of the reservoir sand in cores and also petrographic investigations by optical microscope, scanning electron microscope (SEM) examinations, XRF and microprobe analyses.   The...

  7. 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.

  8. 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)

  9. 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).

  10. An Effective Acid Combination for Enhanced Properties and Corrosion Control of Acidizing Sandstone Formation

    Science.gov (United States)

    Umer Shafiq, Mian; Khaled Ben Mahmud, Hisham

    2016-03-01

    To fulfill the demand of the world energy, more technologies to enhance the recovery of oil production are being developed. Sandstone acidizing has been introduced and it acts as one of the important means to increase oil and gas production. Sandstone acidizing operation generally uses acids, which create or enlarge the flow channels of formation around the wellbore. In sandstone matrix acidizing, acids are injected into the formation at a pressure below the formation fracturing pressure, in which the injected acids react with mineral particles that may restrict the flow of hydrocarbons. Most common combination is Hydrofluoric Acid - Hydrochloric with concentration (3% HF - 12% HCl) known as mud acid. But there are some problems associated with the use of mud acid i.e., corrosion, precipitation. In this paper several new combinations of acids were experimentally screened to identify the most effective combination. The combinations used consist of fluoboric, phosphoric, formic and hydrofluoric acids. Cores were allowed to react with these combinations and results are compared with the mud acid. The parameters, which are analyzed, are Improved Permeability Ratio, strength and mineralogy. The analysis showed that the new acid combination has the potential to be used in sandstone acidizing.

  11. Effect of modified ethylsilicate consolidants on the mechanical properties of sandstone

    Czech Academy of Sciences Publication Activity Database

    Remzová, Monika; Šašek, Petr; Frankeová, Dita; Slížková, Zuzana; Rathouský, Jiří

    2016-01-01

    Roč. 112, JUN 2016 (2016), s. 674-681. ISSN 0950-0618 R&D Projects: GA MK(CZ) DF11P01OVV012 Institutional support: RVO:61388955 ; RVO:68378297 Keywords : sandstones * ethylsilicate consolidant * sol-gel process Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.296, year: 2014

  12. Factors controlling permeability of cataclastic deformation bands and faults in porous sandstone reservoirs

    Science.gov (United States)

    Ballas, Gregory; Fossen, Haakon; Soliva, Roger

    2015-07-01

    Improving the prediction of sub-seismic structures and their petrophysical properties is essential for realistic characterization of deformed sandstone reservoirs. In the present paper, we describe permeability contrasts induced by cataclastic deformation bands and faults in porous sandstones (766 data synthesized from field examples and the literature). We also discuss the influence of several factors, including tectonic regime, presence of a fault, burial depth, host sandstone porosity, and grain size and sorting for their initiation and permeability. This analysis confirms that permeability decrease is as a function of grain-crushing intensity in bands. Permeability reduction ranges from very limited in crush-microbreccia of compaction bands to high permeability reduction in cataclasites and ultracataclasites of shear-dominated bands, band clusters and faults. Tectonic regime, and especially normal-fault regime, with its tendency to localize strain and generate faults, is identified as the most important factor, leading to the formation of cataclastic bands with high permeability contrasts. Moreover, moderate burial depth (1-3 km) favors cataclastic bands with high permeability contrasts with respect to the host sandstone. High porosity, coarse-grain size and good grain sorting can slightly amplify the permeability reductions recorded in bands.

  13. 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.

  14. Recent Atmospheric Deposition and its Effects on Sandstone Cliffs in Bohemian Switzerland National Park, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Vařilová, Z.; Navrátil, Tomáš; Dobešová, Irena

    2011-01-01

    Roč. 220, 1/4 (2011), s. 117-130. ISSN 0049-6979 Institutional research plan: CEZ:AV0Z30130516 Keywords : acid deposition * sandstone percolates * chemical weathering * salt efflorescence * Black Triangle * aluminum * sulfates Subject RIV: DD - Geochemistry Impact factor: 1.625, year: 2011

  15. Diagenesis influencing the porosity of Upper Jurassic reservoir sandstones, Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Weibel, R.; Keulen, N. (Geological Survey of Denmark and Greenland, Copenhagen (Denmark))

    2008-07-15

    Upper Jurassic quartz-rich sandstones in the North Sea Basin are important reservoir rocks for oil and gas, and one of the latest discoveries of oil in the Danish sector was made in the area of the Hejre wells that penetrated such sediments. The reservoir properties of sandstones are strongly influenced by diagenetic alteration, i.e. the mineralogical changes that take place during burial of the sediments. The diagenetic features depend on the source area, depositional setting, facies architecture and burial history of the sediment. The major diagenetic features influencing porosity in Upper Jurassic reservoir sandstones are feldspar dissolution and precipitation of illite, calcite and quartz, and quartz stylolite formation. With regard to the Upper Jurassic sandstones in the Danish sector of the North Sea, the important question is: how can porosity be preserved in sediments buried at depths of more than 5 km? The Hejre-2 well penetrated the Upper Jurassic sediments before reaching pre-Upper Jurassic volcaniclastic conglomerates. The diagenetic features were studied in thin sections of core samples with traditional petrographic techniques using transmitted light microscopy supplemented by scanning electron microscopy (SEM) of rock chips and thin sections. (au)

  16. 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

    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...

  17. 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)

  18. A charcoal record of Holocene woodland succession from sandstone rock shelters of North Bohemia (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Novák, J.; Svoboda, Jiří; Šída, P.; Prostředník, J.; Pokorný, P.

    2015-01-01

    Roč. 366, 24 April (2015), s. 25-36. ISSN 1040-6182 R&D Projects: GA ČR GA13-08169S Keywords : Charcoal * Rock shelters * Sandstone area * Vegetation history * Pollen analysis Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 2.062, year: 2014

  19. Sandstone geomorphology of the Golden Gate Highlands National Park, South Africa, in a global context

    Directory of Open Access Journals (Sweden)

    Stefan W. Grab

    2011-03-01

    Full Text Available The Golden Gate Highlands National Park (GGHNP is well known for its impressive sandstone formations. While previous geoscience research in the park has focused on geology, palaeontology, slope forms and the prominent lichen weathering, remarkably little has been written on the diversity and possible origins of sandstone phenomena in the region. The objectives of this study were (1 to present a geomorphological map of prominent and interesting landforms for particular portions of the park and (2 to document the variety of macro- and microscale sandstone formations observed. During field work, we undertook global positioning system measurements to map landforms and, in addition, measured the dimensions of several landform types. A Schmidt hammer was used to conduct rock hardness tests at a variety of localities and lithologies for comparative purposes. We indentified and mapped 27 macro- and microscale sandstone landforms, of which 17 are described in detail. It is demonstrated that for the most part, the landforms are a likely product of surface lithological reactions to a regional climate characterised by pronounced multitemporal temperature and moisture shifts, recently and in the past. However, many of the geomorphological processes producing landforms are controlled by microclimates set up by factors such as macro- and microtopography. Conservation implications: The GGHNP is best known for its geological, geomorphological and palaeontological heritage. This paper highlights the diversity of sandstone geomorphological phenomena, many of them rare and ‘unique’ to the region. Not only are these landforms of aesthetic interest to tourists, but they also provide microhabitats for biota. Thus, conservation of biota requires associated conservation of geo-environments where they are established.

  20. The sedimentology of uranium-bearing sandstones on the farm Kaffersfontein 328, Beaufort West area

    International Nuclear Information System (INIS)

    The sedimentology of uranium-bearing sandstones on the farm Kaffersfontein 328 was studied by use of 23 vertical profiles measured across and adjacent to 3 mineralised deposits. The profiles consist of 18 field sections and 5 borehole logs. The vertical profiles basically consist of a succession of sedimentary facies. A total of 18 facies were recognised within the fluvial sandstone sequence according to the criteria of grain-size and sedimentary structures. Transitions between the facies were subjected to a Markov chain analysis in order to delineate Markov-dependent transitions. Uranium mineralisation coincides with areas of thicker sandstone, usually where channel over-deepening has taken place. It always occurs above the base of a channel, which often marks the base of the fluvial sandstone sequence. Irregularities in the base of the channel probably caused interruptions to the flow of uraniferous solutions and allowed sufficient time for the precipitation of the uranium. Carbonaceous debris is always associated with the mineralisation and most likely acted as an indirect reductant for the precipitation of uranium from solution. The direct reductant was most probably H2S produced by anaerobic bacteria acting on the carbonaceous debris. The mineralisation is confined to the coarser-grained sedimentary facies, which suggests that permeability was an important control on the mineralisation. These facies probably acted as suitable aquifers for the transport of uraniferous solutions. Horizontally bedded sandstone facies comprises 41 per cent of the total cumulative thickness of mineralisation. This facies represents a higher stream power and may consequently contain more carbonaceous material derived from plants, which were eroded from upstream areas. The nature of the bedding may also have provided a more effective permeability zone for the transport of uraniferous solutions prior to precipitation of the uranium

  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. 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

  3. Discrete element modeling on the crack evolution behavior of brittle sandstone containing three fissures under uniaxial compression

    Science.gov (United States)

    Yang, Sheng-Qi; Huang, Yan-Hua; Ranjith, P. G.; Jiao, Yu-Yong; Ji, Jian

    2015-12-01

    Based on experimental results of brittle, intact sandstone under uniaxial compression, the micro-parameters were firstly confirmed by adopting particle flow code (PFC^{2D}). Then, the validation of the simulated models were cross checked with the experimental results of brittle sandstone containing three parallel fissures under uniaxial compression. The simulated results agreed very well with the experimental results, including the peak strength, peak axial strain, and ultimate failure mode. Using the same micro-parameters, the numerical models containing a new geometry of three fissures are constructed to investigate the fissure angle on the fracture mechanical behavior of brittle sandstone under uniaxial compression. The strength and deformation parameters of brittle sandstone containing new three fissures are dependent to the fissure angle. With the increase of the fissure angle, the elastic modulus, the crack damage threshold, and the peak strength of brittle sandstone containing three fissures firstly increase and secondly decrease. But the peak axial strain is nonlinearly related to the fissure angle. In the entire process of deformation, the crack initiation and propagation behavior of brittle sandstone containing three fissures under uniaxial compression are investigated with respect to the fissure angle. Six different crack coalescence modes are identified for brittle sandstone containing three fissures under uniaxial compression. The influence of the fissure angle on the length of crack propagation and crack coalescence stress is evaluated. These investigated conclusions are very important for ensuring the stability and safety of rock engineering with intermittent structures.

  4. 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...

  5. 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.)

  6. 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.

  7. 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...

  8. Origin of “rock cities”, pillars and cleft-conduits in kaolinite-bonded sandstone: New insight from study in sandstone quarry where landforms recently evolve

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Soukup, J.; Schweigstillová, Jana; Vaculíková, J.; Smutek, D.; Mayo, A. L.; Falteisek, L.

    Vol. 3. Prague : Česká speleologická společnost, 2013 - (Filippi, M.; Bosák, P.), s. 247-252 ISBN 978-80-87857-09-0. [International Congress of Speleology /16./. Brno (CZ), 21.07.2013-28.07.2013] R&D Projects: GA ČR GA13-28040S Institutional support: RVO:67985891 Keywords : case hardening erosion * fluidization * overland flow * piping * sandstone landforms Subject RIV: DB - Geology ; Mineralogy http://www.karstportal.org/FileStorage/Intl_Congress_of_Speleology/seka_pdf13563.pdf

  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. 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

  11. 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.

  12. Chemical and physical hydrogeology of coal, mixed coal-sandstone and sandstone aquifers from coal-bearing formations in the Alberta Plains region, Alberta

    International Nuclear Information System (INIS)

    With the decline of conventional oil and gas reserves, natural gas from coal (NGC) is an unconventional gas resource that is receiving much attention from petroleum exploration and development companies in Alberta. Although the volume of the NGC resource is large, there are many challenges facing NGC development in Alberta, including technical and economic issues, land access, water disposal, water diversion and access to information. Exploration and development of NGC in Alberta is relatively new, therefore there is little baseline data on which to base regulatory strategies. Some important information gaps have been filled through water well sampling in coal, mixed coal-sandstone and sandstone aquifers throughout Alberta. Analyses focused on the chemical and physical characteristics aquifers in use for domestic or agricultural purposes. Aquifer depths were generally less than 100 metres. Samples collected from Paskapoo-Scollard Formation, Horseshoe Canyon Formation and Belly River Group aquifers exceed Canadian water quality guideline values with respect to pH, sodium, manganese, chloride, chromium, sulphate, phenols and total dissolved solids. Pump tests conducted within the aquifers indicate that the groundwater flow is complicated. Water quality will have to be carefully managed to ensure responsible disposal practices are followed. Future studies will focus on understanding the chemical and biological process that occur within the aquifers and the possible link between these processes and gas generation. Mitigation and disposal strategies for produced water will also be developed along with exploration strategies using information obtained from hydrogeologic studies. 254 refs., 182 tabs., 100 figs., 3 appendices

  13. 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.

  14. 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

  15. Ultrasonic Frequency Difference Generation to Characterize Fluids in Saturated Berea Sandstone.

    Energy Technology Data Exchange (ETDEWEB)

    Keatkowski, C. S. (MST-11); Sinha, D. N. (Dipen N)

    2001-01-01

    The use of nonlinear acoustics to characterize fluids in porous media is presented. The acoustic nonlinearity in sandstone is affected by the presence of water or oil. This difference in properties that affect the sound propagation through such media can be used to determine whether a piece of sandstone contains water or oil. Traditional methods of characterizing porous media usually rely on the transmission or reflection of a single ultrasonic probe pulse. The technique presented in this paper uses a method of generating a probe pulse inside the porous medium from the interaction of two pulses. Information about the medium is then contained in the propagation of this probe signal back to a receiver. The main advantage of this approach is that it allows implementation of this technique inside a borehole for characterizing the porous media outside.

  16. 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.

  17. Remote sensing technology prospecting methods of interlayer oxidation zone type sandstone uranium deposit in Yili basin

    International Nuclear Information System (INIS)

    Taking Yili Basin as an example, remote sensing technology and method of interlayer oxidation zone type sandstone uranium deposit have systematically been summarized. Firstly, principle, methods and procedures of the second development of scientific experimental satellite photograph have been elaborated in detail. Three dimensional stereo simulation, display, and multi-parameters extraction have been recommended. Secondarily, the research is focused on prospective section image features in different type images and their geological implications and on establishing recognition keys of promising areas. Finally, based on above research results, three graded predictions, i.e. regional prospect, promising sections and favourable location in the deposit have been made step by step and reconnaissance and prospecting range are gradually reduced. The practice has indicated that breakthrough progress has been made in application to prospect prognosis of interlayer oxidation zone type sandstone uranium deposit and good verified results have been obtained

  18. Tectono-sedimentary evolution of Erlian basin since late mesozoic and sandstone-hosted uranium metallogenesis

    International Nuclear Information System (INIS)

    Various mineral resources in a basin are associated with its tectono-sedimentary evolution. Based on the analysis of the tectono-sedimentary evolution of Erlian basin, three evolutional stages of Erlian basin are classified, they are: the continental extensional down-faulting stage, the transitional stage from down-faulting to down-warping in Early Cretaceous, and slightly compressional differentiated uplifting-subsidence since Late Cretaceous. According to the mechanism of sandstone-hosted uranium metallogenesis it is suggested that the grey clastic rock series deposited at the stage of down-faulting down-warping transition must be the important target for uranium prospecting, and the differentiated uplifting-subsidence offers necessary conditions for sandstone-hosted uranium ore-formation. Then, types of uranium mineralization that could occur in Erlian basin are discussed, and uranium metallogenic model has been preliminarily summarized. (authors)

  19. 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

    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......, in the unamended microcosm. For microcosm systems. with solid aquifer materials. dissolution of organic substances from the solid material may occur. A quantitative determination of the speciation (mineral types and quantity) of electron acceptors associated with the solids, at levels relevant for degradation......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...

  20. Exploration orientation of leachable sandstone type uranium deposit in Erlian basin

    International Nuclear Information System (INIS)

    Erlian basin is a large meso-cenozoic uraniferous basin.Great achievement of leachable sandstone type uranium deposit exploration has been made in the basin in recent years. By systematicaly summarizing and analyzing exploratory results, this article has established the principle for ascertaining target layer and put forward Saihan formation as the main target layer and Erlian formation and Yierdingmanha formation as the secondary target layers for uranium exploration in Erlian basin. The exploratory type in Erlian basin is inter-layered oxidation type(including phreatic-interlayer type). Besides, this article summarizes the criterions for uranium exploration and analyzes the exploratory prospect and orientation. The paper points out that the south edge of Bayinbaolige uplift (northern part of Wulanchabu depression and Manite depression) is the most favorable area for leachable sandstone type uranium deposits exploration in Erlian basin. (authors)

  1. Inversion structure and its contribution to sandstone uranium metallogenesis in southeast uplifted domain of Songliao basin

    International Nuclear Information System (INIS)

    Many positive inversion structures were developed during the end of Nenjiang period in southeast Songliao basin Main styles of inversion structures are inversion anticline in downfaulted and depression sequence, positive footwall and negative upthrown block in downfaulted sequence, negative footwall and upthrown block in downfaulted sequence, negative footwall and upthrown block in depression sequence. Structure inversions may contribute to sandstone uranium ore-formation because they changed the structure shape, physical properties, circulating way of groundwater, geochemical property of rocks in shallow depression layer of the basin and lead to the ascending migration of oil-gas, CO2. Thus, denudation window areas are favorable for sandstone uranium ore-formation and attention must be paid to denudation window areas in Southeast uplifted domain of Songliao basin. (authors)

  2. 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.

  3. 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.

  4. Pore Fluid Effects on Shear Modulus for Sandstones with Soft Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J G

    2004-04-15

    A general analysis of poroelasticity for vertical transverse isotropy (VTI) shows that four eigenvectors are pure shear modes with no coupling to the pore-fluidmechanics. The remaining two eigenvectors are linear combinations of pure compression and uniaxial shear, both of which are coupled to the fluid mechanics. After reducing the problem to a 2x2 system, the analysis shows in a relatively elementary fashion how a poroelastic system with isotropic solid elastic frame, but with anisotropy introduced through the poroelastic coefficients, interacts with the mechanics of the pore fluid and produces shear dependence on fluid properties in the overall mechanical system. The analysis shows, for example, that this effect is always present (though sometimes small in magnitude) in the systems studied, and can be quite large (up to a definite maximum increase of 20 per cent) in some rocks--including Spirit River sandstone and Schuler-Cotton Valley sandstone.

  5. 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.

  6. 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)

  7. 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)

  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. The laboratory study on a sandstone uranium ore in-situ leaching

    International Nuclear Information System (INIS)

    Uranium mineral of a sandstone uranium ore and its composition were investigated, Based on the investigated , the leaching technology and parameters were selected through experiments, the U leaching rate to 92.81% use 15 g/L H2SO4, the U leaching rate to 84.24% use 10 g/LNa2CO3 + 5 g/LNaHCO3. Column leaching test using five test column, leaching rate respectively: 95.58%, 98.11%, 59.39%, 46.14%, 59.39%. After approximately 12 void volume laundering, the water quality in ore at or near background values of ore-bearing aquifer. The results from agitation leaching and column leaching experiments show that the sandstone uranium suitable for ISL mining methods. (authors)

  10. Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

    DEFF Research Database (Denmark)

    Sliaupa, S.; Cyziene, J.; Molenaar, Nicolaas;

    2008-01-01

    The conditions and timing of carbonate cementation in Cambrian sandstones of the Baltic sedimentary basin were determined by oxygen and carbon stable isotope and chemical data in combination with optical and cathodoluminescence petrographic studies. Studied samples represent a range in present...... burial depth from 340 to 2150 m. The carbonate cement is dominantly ferroan dolomite that occurs as dispersed patches of poikilotopic crystals. Temperatures of dolomite precipitation, based on delta O-18 values, range from 27 degrees C in the shallow buried to 95 degrees C in the deep buried sandstones....... The burial history modelling points to development of most of the dolomite cement during rapid Silurian-Devonian subsidence and Carboniferous-early Permian uplift. A wide range of precipitation temperatures indicate that temperature was not a major factor in triggering the carbonate cementation. Dolomite...

  11. 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...

  12. A Case Report of Sarcoptes scabiei Infection in Ahwaz, Iran

    Directory of Open Access Journals (Sweden)

    M Rahdar

    2008-06-01

    Full Text Available The prevalence of Sarcoptes in rural areas has been investigated by many investigators. Sarcoptes infestation in areas with poor education and hygienic is higher than urban areas. In this study, one severe case of Sarcoptes scabiei in­festation is described from a four months old child. Confirmation of scabies was done by clinical examination of child and by the identification of the mite by microscopically examining scrapings from the scabies lesions. The prevalence of scabies is high in children in rural regions, suggesting that it is a serious public health problem. This phenomenon may be due to the fact that certain environmental conditions such as overcrowding, poor personal hy­giene, poverty, and ignorance, which are conducive to the spread of scabies, tend to be quite common in rural re­gions. Control programs should be put in place and implemented in an integrated manner, by reducing overcrowding, and by improving health education, personal hygiene, treatment and surveillance among high-risk populations.

  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. Comparative study of models for predicting permeability from nuclear magnetic resonance (NMR) logs in two Chinese tight sandstone reservoirs

    Science.gov (United States)

    Xiao, Liang; Liu, Xiao-Peng; Zou, Chang-Chun; Hu, Xiao-Xin; Mao, Zhi-Qiang; Shi, Yu-Jiang; Guo, Hao-Peng; Li, Gao-Ren

    2014-02-01

    Based on the analysis of mercury injection capillary pressure (MICP) and nuclear magnetic resonance (NMR) experimental data for core plugs, which were drilled from two Chinese tight sandstone reservoirs, permeability prediction models, such as the classical SDR, Timur-Coates, the Swanson parameter, the Capillary Parachor, the R10 and R35 models, are calibrated to estimating permeabilities from field NMR logs, and the applicabilities of these permeability prediction models are compared. The processing results of several field examples show that the SDR model is unavailable in tight sandstone reservoirs. The Timur-Coates model is effective once the optimal T 2cutoff can be acquired to accurately calculate FFI and BVI from field NMR logs. The Swanson parameter model and the Capillary Parachor model are not always available in tight sandstone reservoirs. The R35 based model cannot effectively work in tight sandstone reservoirs, while the R10 based model is optimal in permeability prediction.

  15. 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)

  16. 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.

  17. Discuss sandstone-type uranium geology and exploration prospects of Sujiapo location in Zaohuohao area

    International Nuclear Information System (INIS)

    Zaohuohao uranium deposit is a large domestic uranium deposits, with deposits in the region more in-depth work, looking for new prospective areas outlying areas, as the necessary work. Based on field work and drilling data series compiled the fruits of the interior, a simple analysis of Zaohuohao uranium deposits in the outlying areas of the Soviet Union home lots slope sandstone-type uranium geology, uranium summarizes the geological conditions of the lot that the lot has a good prospecting. (author)

  18. 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...

  19. Sandstone columns of the 3rd Nile Cataract (Nubia, Northern Sudan)

    Czech Academy of Sciences Publication Activity Database

    Cílek, Václav; Adamovič, Jiří; Suková, L.

    2015-01-01

    Roč. 59, Supplement 1 (2015), s. 151-165. ISSN 0372-8854 Grant ostatní: Program interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100130902 Institutional support: RVO:67985831 Keywords : Nubian sandstone * columnar jointing * Voronoi fragmentation * 3rd Nile Cataract * Sudan Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.734, year: 2014

  20. 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...

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. Cave formation initiated by dissolution of carbonate cement in qartzose sandstones

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří; Mikuláš, Radek; Navrátil, Tomáš; Mertlík, J.

    Vol. 3. Prague : Česká speleologická společnost, 2013 - (Filippi, M.; Bosák, P.), s. 217-220 ISBN 978-80-87857-09-0. [International Congress of Speleology /16./. Brno (CZ), 21.07.2013-28.07.2013] R&D Projects: GA AV ČR IAA300130806 Institutional support: RVO:67985831 Keywords : caves * sandstones * carbonate cement Subject RIV: DB - Geology ; Mineralogy

  6. 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

  7. Mechanism of primary and secondary oil flooding for recovery from sandstone by low salinity water

    OpenAIRE

    Mamonov, Aleksandr

    2014-01-01

    Low salinity water flooding (LSW) as an enhanced oil recovery (EOR) method has been discussed by many researchers, but consistent approved mechanism is still not found. The main reason of lack of clear understanding of the process is complexity of the oil/brine/rock interactions. Therefore, theme of this project was chosen to study the mechanism(s) behind the low salinity EOR by flooding different brines through the sandstone cores and analyzing obtained data. This thesis contains a litera...

  8. Dictyonema black shale and Triassic sandstones as potential sources of uranium

    OpenAIRE

    Kiegiel Katarzyna; Zakrzewska-Kołtuniewicz Grażyna; Gajda Dorota; Miśkiewicz Agnieszka; Abramowska Anna; Biełuszka Paweł; Danko Bożena; Chajduk Ewelina; Wołkowicz Stanisław

    2015-01-01

    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 me...

  9. 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.

  10. Core flooding laboratory experiment validates numerical simulation of induced permeability change in reservoir sandstone

    OpenAIRE

    Bartels, J.; Michael Kühn; W. Schneider; C. Clauser; Pape, H.; V. Meyn; I. Lajczak;  

    2002-01-01

    Numerical simulation of reactive transport was validated in a core flooding experiment simulating conditions in a managed geothermal reservoir. Permeability was measured along a sandstone core prepared with anhydrite and subjected to a temperature gradient. Anhydrite was dissolved and precipitated in the cold upstream and hot downstream regions of the core, respectively. The numerical code SHEMAT was used to simulate coupled transport and chemical reactions at the temperature front. It compri...

  11. Evaluation of Transport Through Sandstone and Limestone Cores of PAHs Dissolved Groundwater

    Science.gov (United States)

    Lasseigne, A. E.; Blanford, W. J.

    2006-12-01

    In this study, data on the transport characteristics within the rock matrix of limestone and sandstone of naphthalene dissolved in groundwater has been gathered. This information has been collected from miscible displacement studies executed with cores of Berea Sandstone and Edwards Aquifer Limestone. This entailed placing 2 inch diameter by 1 and 3 inch long cores in a Hassler type 2 core holder and flooding with aqueous solutions of naphthalene and for comparison bromide and penta-fluorinated benzoic acid. The results of these tracer studies were compared to 1D and 3D numerical simulations based on characteristics of the tracers and analysis of the compositional and hydraulic properties of the cores. Bulk mineral composition was determine with X-ray diffraction and organic matter content with a total organic carbon analyzer. Mean porosity was determined through comparison of precise dry and wet masses, and variability in porosity of the rock samples was determined by impregnation with epoxy and analysis of backscatter images from scanning electron microscope (SEM). Saturated hydraulic conductivity was determined by measuring differential pressures across rock columns under a range of flow rates from 0.49 to 0.87 ml/min. Using 1D numerical program STANMOD, dispersivity coefficients for the sandstone cores were determined through inverse models of the bromide and PFBA data. With this value, the naphthalene tracer results were found to be most closely simulated with a model with mixture of 10% equilibrium mass transfer and 90% rate- limited sorption sites. This analysis also yielded an R = 1.6 for naphthalene. Multi-dimensional modeling of sandstone using MODFLOW and MT3DMS and modeling of the limestone tracer studies is currently underway and will be presented.

  12. Thermal effects of magma emplacement and the origin of columnar jointing in host sandstone

    Czech Academy of Sciences Publication Activity Database

    Adamovič, Jiří

    Birmingham : University of Birmingham, Kingston University, 2006 - (Thomson, K.), s. 22-24 [Physical geology of subvolcanic systems: Laccoliths, sills and dykes (LASI) /2./. Birmingham ; Portree, Isle of Skye (GB), 01.04.2006-03.04.2006] R&D Projects: GA AV ČR IAA3013302 Institutional research plan: CEZ:AV0Z30130516 Keywords : dyke * sandstone * columnar jointing * heat sources Subject RIV: DB - Geology ; Mineralogy

  13. 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...

  14. 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

  15. 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...

  16. 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.

  17. 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.

  18. In situ measurements of impact-induced pressure waves in sandstone targets

    Science.gov (United States)

    Hoerth, Tobias; Schäfer, Frank; Nau, Siegfried; Kuder, Jürgen; Poelchau, Michael H.; Thoma, Klaus; Kenkmann, Thomas

    2014-10-01

    In the present study we introduce an innovative method for the measurement of impact-induced pressure waves within geological materials. Impact experiments on dry and water-saturated sandstone targets were conducted at a velocity of 4600 m/s using 12 mm steel projectiles to investigate amplitudes, decay behavior, and speed of the waves propagating through the target material. For this purpose a special kind of piezoresistive sensor capable of recording transient stress pulses within solid brittle materials was developed and calibrated using a Split-Hopkinson pressure bar. Experimental impact parameters (projectile size and speed) were kept constant and yielded reproducible signal curves in terms of rise time and peak amplitudes. Pressure amplitudes decreased by 3 orders of magnitude within the first 250 mm (i.e., 42 projectile radii). The attenuation for water-saturated sandstone is higher compared to dry sandstone which is attributed to dissipation effects caused by relative motion between bulk material and interstitial water. The proportion of the impact energy radiated as seismic energy (seismic efficiency) is in the order of 10-3. The present study shows the feasibility of real-time measurements of waves caused by hypervelocity impacts on geological materials. Experiments of this kind lead to a better understanding of the processes in the crater subsurface during a hypervelocity impact.

  19. Hypervelocity impacts on dry and wet sandstone: Observations of ejecta dynamics and crater growth

    Science.gov (United States)

    Hoerth, Tobias; SchńFer, Frank; Thoma, Klaus; Kenkmann, Thomas; Poelchau, Michael H.; Lexow, Bernd; Deutsch, Alexander

    2013-01-01

    This study deals with the investigation of highly dynamic processes associated with hypervelocity impacts on porous sandstone. For the impact experiments, two light-gas accelerators with different calibers were used, capable of accelerating steel projectiles with diameters ranging from 2.5 to 12 mm to several kilometers per second. The projectiles impacted on dry and water-saturated Seeberger Sandstone targets. The study includes investigations of the influence of pore water on the shape of the ejecta cloud as well as transient crater growth. The results show a significant influence of pore water on ejecta behavior. Steeper ejecta cone angles are observed if the impacts are conducted on wet sandstones. The transient crater grows at a faster rate and reaches a larger diameter if the target is water saturated. In our experiments, target porosity leads to smaller crater sizes compared with nonporous targets. Water within the pore space reduces porosity and counteracts this process. Power law fits were applied to the crater growth curves. The results show an increase in the scaling exponent μ with increasing pore space saturation.

  20. 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.

  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. 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.

  3. Microstructural Imaging of Shock-Recovered Berea Sandstone and Quartz Sand Using Scanning Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hiltl, M.; Hagelberg, C.R.; Swift, R.P.; Nellis, W.J.

    2000-02-03

    A number of shock-recovery experiments have been performed on Berea sandstone for different conditions: dry, water-saturated, hydrostatically water-pressurized and Helium gas-pressurized. The authors also conducted experiments with purified quartz sand in dry and water-saturated conditions with a grain size between 212 to 250 {micro}m and 250 to 300 {micro}m to compare with damaged Berea sandstone. The shock stresses in the range between 1.2 to 9.8 GPa were achieved by impacting projectiles accelerated by a single-stage light-gas gun. Different flyer plate thicknesses were used to produce different shock pulse durations. The water-pressurized sandstone targets were hydrostatically pressurized between 7.58-7.79 MPa, whereas the gas-pressure samples were pressurized to 27.5 MPa using helium gas. The microstructural damage of all specimens is being investigated by using scanning electron microscopy (SEM) in order to determine differences for these conditions. In this report they will present the results of the systematic SEM investigations for each experiment. The scientific results and discussions including X-ray computed micro tomography and statistical analysis are presented elsewhere. Overall, they collected around 1600 SEM pictures, which are available in electronic form on Compact Disks (CDs). They also provide the results of the laser particle analysis on the CDs.

  4. Laboratory measurements of a complete set of poroelastic moduli for Berea sandstone and Indiana limestone

    Science.gov (United States)

    Hart, David J.; Wang, Herbert F.

    1995-09-01

    Measurements have been completed for eight different poroelastic moduli of water-saturated Berea sandstone and Indiana limestone as a function of confining pressure and pore pressure. The poroelastic moduli for Indiana limestone are generally consistent to ±10%, which was verified by a formal inversion procedure for independent moduli from the eight measurements. For Indiana limestone, best fit values were drained bulk modulus, 21.2 GPa; the undrained bulk modulus, 31.7 GPa; drained Poisson's ratio, 0.26; undrained Poisson's ratio, 0.33; and pore pressure buildup coefficient, 0.47 at 20-35 MPa effective stress. The poroelastic moduli for Berea sandstone are generally consistent to ±20%. The greater inconsistency is most likely caused by the nonlinear variation of the moduli at different strains. For Berea sandstone, best fit values were drained bulk modulus, 6.6 GPa; undrained bulk modulus, 15.8 GPa; drained Poisson's ratio, 0.17; undrained Poisson's ratio, 0.34; and pore pressure buildup coefficient, 0.75 at 10 MPa effective stress.

  5. 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.

  6. 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.

  7. 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. PMID:14684213

  8. 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)

  9. Influence of reservoir stress path on deformation and permeability of weakly cemented sandstone reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ruistuen, H.; Teufel, L.W.; Rhett, D.

    1996-12-31

    The influence of production-induced changes in reservoir stress state on compressibility and permeability of weakly cemented sandstones has been analyzed. Laboratory experiments simulating reservoir depletion have been conducted for the full range of stress paths that a reservoir may follow. Samples were loaded by reducing the pore pressure and controlling the confining pressure according to the desired stress path from initial reservoir conditions. The results show that compressibility of weakly cemented sandstones are stress path dependent. Compressibilities measured under uniaxial strain conditions, or a stress path with a K value lower than the one associated with uniaxial strain, are more than twice the corresponding value found under hydrostatic loading conditions. In contrast, matrix permeability measured in the maximum stress direction show no significant stress path dependence. Independently of stress path, the observed permeability reductions fall within the general trend expected for a sedimentary rock of relatively high initial permeability. A significant permeability decrease was only observed as the shear stress exceeded the yield limit of the rock, probably due to both mobilization of fine arains and an increase in tortuosity due to collapse of pore space. Results of this study suggest that stress path dependent properties of weakly cemented sandstones is a consequence of the heterogeneous nature of the sedimentary rock. Material properties are affected by grain-scale inelastic deformation processes and the pattern of these deformation processes is primarily controlled by reservoir stress path.

  10. Study on the structure characteristic of the low permeable sandstone uranium ore rock

    International Nuclear Information System (INIS)

    In order to study the structure characteristic of the low permeable sandstone ore rock as well as the influence of the structure on the penetration ratio, this paper based on the mercury intrusion experiment to analyze the fractal characteristics of the pore and pore specific surface distribution in the low permeable sandstone uranium rock, and study the relation between the structure characteristic and porosity. The study indicates that there are double-fractal characteristics of the structure in the low permeable sandstone uranium rock, it mainly shows the fractal dimension value of the pore distribution and pore specific surface distribution is different with the pore of small and large aperture. The fractal dimension of the pore distribution with the large aperture ranges from 3.687 to 4.255, while that with the small aperture ranges from 3.101 to 3.208. And, the fractal dimension of the pore specific surface distribution with the big particle mass ranges from 2.910 to 3.151, and that with the small aperture ranges from 2.466 to 2.342, and that the relation between the porosity and the fractal dimension of the large aperture is positive correlation, but is negative correlation between the porosity and the fractal dimension of the pore specific surface distribution in the large aperture. (authors)

  11. 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.

  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. PETROFACIES CHARACTERISTICS OF THE SANDSTONES OF THE UPPER MIOCENELOWER PLIOCENE AGED IN THE ULUMUHSİNE-TATKÖY (KONYA AREA

    Directory of Open Access Journals (Sweden)

    A. Müjdat ÖZKAN

    2000-03-01

    Full Text Available In the study area, Upper Miocene-Lower Pliocene aged Ulumuhsine formation, was formed in a shallow, open lake and river environment. The lithologies of this formation are thin-medium bedded, laminated and fossil rich limestone, thin-thick bedded mudstone, thin-thick bedded marl, thin-thick bedded dolomite with stromatolite interbedded limestone, tuffite, chert bands and coal-rich levels. In addition, it includes conglomerates and sandstones of underwater distrubution channels in lacustrine, and channel and bar sediments in stream environments. Red, gray, rarely green colored sandstones are thin-thick bedded, and in some levels well sorting, in some levels proorly sorting. They present sedimentary structures, as graded, herringbone cross-bedding, symmetric ripple-marks, and laminate. Sandstones are named lithic arenite and lithic graywacke and litharenite, feldspathic litharenite and sublithic arenite. These sandstones are rich rock fragments and quartzs, in addition they contain plagioclase, biotite, muskovite, opaque mineral and epidote. Binding materials of sandstones are mainly calcite cements and clay matrix, and iron oxide cement in little amount. From the mineralogical and textural point of view. As a tectonic environment, the main source of sandstones are recycled orogen (thrust, collision and land uplift and recyded lithic fragments.

  14. 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)....

  15. Traction member for flight conveyors

    Energy Technology Data Exchange (ETDEWEB)

    Gorlov, V.M.; Levin, A.G.; Spivak, I.V.

    1989-12-20

    A traction member of a flight conveyor, comprising successive flights connected through vertical studs with the straight portions of the vertical links of the respective vertically spaced chains forming closed loops in a horizontal plane, each said flight being detachably assembled from a central part and two yoke-shaped end parts, each said end part accommodating in the opening thereof the end portion of the central part of the flight and a portion of said vertical stud, this stud having heads at its opposite ends of a diameter greater than the width of said opening, one of said heads having a through slot for joining said stud with the straight portions of the respective vertical link of the respective one of said chains.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. Quantitative mineralogical analysis of sandstones using x-ray diffraction techniques

    International Nuclear Information System (INIS)

    Full text: X-ray diffraction has long been used as a definitive technique for mineral identification based on the measuring the internal atomic or crystal structures present in powdered rocks; soils and other mineral mixtures. Recent developments in data gathering and processing, however, have provided an improved basis for its use as a quantitative tool, determining not only the nature of the minerals but also the relative proportions of the different minerals present. The mineralogy of a series of sandstone samples from the Sydney and Bowen Basins of eastern Australia has been evaluated by X-ray diffraction (XRD) on a quantitative basis using the Australian-developed SIROQUANT data processing technique. Based on Rietveld principles, this technique generates a synthetic X-ray diffractogram by adjusting and combining full-profile patterns of minerals nominated as being present in the sample and interactively matches the synthetic diffractogram under operator instructions to the observed diffractogram of the sample being analysed. The individual mineral patterns may be refined in the process, to allow for variations in crystal structure of individual components or for factors such as preferred orientation in the sample mount. The resulting output provides mass percentages of the different minerals in the mixture, and an estimate of the error associated with each individual percentage determination. The chemical composition of the mineral mixtures indicated by SIROQUANT for each individual sandstone studied was estimated using a spreadsheet routine, and the indicated proportion of each oxide in each sample compared to the actual chemical analysis of the same sandstone as determined independently by X-ray fluorescence spectrometry. The results show a high level of agreement for all major chemical constituents, indicating consistency between the SIROQUANT XRD data and the whole-rock chemical composition. Supplementary testing with a synthetic corundum spike further

  2. Uranium mineralization in late cretaceous sandstones in parts of Meghalaya, India

    International Nuclear Information System (INIS)

    Full text: Late Cretaceous Lower Mahadek sandstone of Meghalaya has been established as the potential host rock for sandstone type of uranium mineralization in India. Till date nearly 16 000 tonnes of U3O8 reserves have been estimated in four locations viz., Domiasiat, Wahkyn, Tyrnai and Lostoin, in the southern part of Meghalaya plateau. The uranium investigations are primarily confined to in the areas where the Lower Mahadek sandstones are exposed either on the surface or along deep river cuttings, otherwise concealed by thick cover of Tertiary sediments. The area poses major logistic challenge due to thick forest and remoteness. Out of nearly 1 800 km2 of extent of the Mahadek Basin, only 28% of the area exposes Lower Mahadek sediments. Survey in recent years has also established few more occurrences at Umthongkut, Wahkut and Rongcheng Plateau in Balphakram area. Systematic study of available surface and subsurface data has revealed that mineralization is controlled by palaeo channel configuration of Mahadek sediments and also the typical geochemical interface. Regional and local tectonics also have played an important role in distribution and concentration of uranium mineralization in the area. It is observed that the deposits and the very promising occurrences described above fall strikingly along an E-W lineament. Lithostructural studies indicate that the southern block appears to have gone upwards relative to the northern block in contrast to other such signatures in the area. This might have influenced ground hydrodynamic flow pattern and helped in concentration of uranium. The Lower Mahadek sandstones, host rock of these deposits are mostly sub-arkosic to arkosic, grading sometimes to felspathic arenite. The main uranium minerals are pitchblende, coffinite and organouranyl complex. Uranium mineralization is associated with bituminous organic matter occurring as dense inclusions, isolated clusters and lumps of various sizes and as clayey - dusty organic

  3. Uranium mineralization in late Cretaceous sandstones in parts of Meghalaya, India

    International Nuclear Information System (INIS)

    Late Cretaceous Lower Mahadek sandstone of Meghalaya has been established as the potential host rock for sandstone type of uranium mineralisation in India. To date, nearly 16 000 tonnes of U3O8 reserves have been estimated in four locations viz., Domiasiat, Wahkyn, Tyrnai and Lostoin, in the southern part of Meghalaya plateau. The uranium investigations are primarily confined to the areas where the Lower Mahadek sandstones are exposed either on the surface or along deep river cuttings, otherwise concealed by thick cover of Tertiary sediments. The area poses major logistical challenges due to thick forest and remoteness. Out of nearly 1 800 km2 of extent of the Mahadek Basin, only 28% of the area exposes Lower Mahadek sediments. The discovery of uranium mineralization so far achieved, is confined to the exposed area. Survey in recent years has also established a few more occurrences at Umthongkut, Wahkut and Rongcheng Plateau in Balphakram area. These occurrences exhibit very strong uranium mineralization on the surface and are technically ripe for exploratory drilling. Large scale exploratory drilling is planned in these areas, which may substantially add to the uranium resources of the region. Systematic study of available surface and subsurface data has revealed that mineralization is controlled by palaeo channel configuration of Mahadek sediments and also the typical geochemical interface. Regional and local tectonics also have played an important role in distribution and concentration of uranium mineralisation in the area. It is observed that the deposits and the very promising occurrences described above fall strikingly along an E-W lineament. Litho-structural studies indicate that the southern block appears to have gone upwards relative to the northern block in contrast to other such signatures in the area. This might have influenced ground hydrodynamic flow pattern and helped in concentration of uranium. The Lower Mahadek sandstones, host rock of these

  4. 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

  5. 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...

  6. The Members of the Agency (French Edition)

    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

  7. The Members of the Agency (Spanish Edition)

    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

  8. Depositional environment of Brushy Basin Member, Morrison Formation, in Gulf Mariano Lake mine, McKinley County

    International Nuclear Information System (INIS)

    The Mariano Lake mine, McKinley County, New Mexico, is developed in the lower portion of the Brushy Basin Member of the Morrison Formation (Upper Jurassic). The sandstones typically are arkosic to subarkosic, moderately to poorly sorted, medium to coarse grained, subrounded, carbonaceous, and silica cemented. Early emplacement of uranium minerals occurred along geochemical boundaries in a roll-front geometry. In the area of the Mariano mine, the Brushy Basin member was deposited as a series of stacked, lenticular-shaped sand bodies interfingering with bentonitic mudstones. Petrologic and sedimentologic data allow the interval to be divided into four depositional facies. These facies represent in-channel and flood-basin deposits of a braided-stream complex with characteristics of the present-day Platte River and Bijou Creek

  9. Petrographic characteristic of the sandstones of the upper paleocene-middle eocene aged in the Yildizli-Aydinkent (Ereğli-Konya area

    Directory of Open Access Journals (Sweden)

    A. Müjdat Özkan

    2002-03-01

    Full Text Available In the study area, Upper Paleocene - Middle Eocene aged Halkapınar formation, was formed in a shallow and deep marine environment. The lithologies of this formation are medium - thick bedded conglomerate, thin - thick bedded sandstone, thin - very thick bedded shale, thin - medium bedded marl with chert nodules and bands. In addition olistolithes of ophiolitic melange are found at the top of the sandstones, which includes basalt interbands. Yellowish gray, greenish gray, beige, gray colored sandstones include some sedimentary structures, namely ripple - marks, graded bedding, laminate, convolute lamination, current ripple, tool marks. Constituents of the sandstones are quartz, plagioclase, sanidine, orthoclase, fragments of sedimentary and methamorphic rocks, biotite, muscovite, opaque mineral and glauconite. The sandstones, which are not matured in terms of mineralogy and texture, are mainly cemented by calcite, clay matrix and minor iron oxide and glauconite matrix. The sandstones are named lithic arenite, lithic graywacke, feldspathic litharenite and litharenite.

  10. Compaction Localization in Notched Samples of Bentheim and Berea Sandstones: Mechanical Experiments, Microstructural Observations and Stress Analysis

    Science.gov (United States)

    Vajdova, V.; Tembe, S.; Zhu, W.; Wong, T.

    2004-12-01

    Compaction band formation has been documented in field and laboratory studies as a localized failure mode in porous sandstones. To simulate the development of compaction bands induced by local stress concentration, we introduced a V-shaped circumferential notch in cylindrical samples of Bentheim and Berea sandstones and conducted triaxial compression tests at a range of confining pressures from 150 to 350 MPa. Our mechanical and microstructural data indicate that the stress concentration caused a compaction band to initiate at the notch tip as a cluster of fractured. The critical differential stress for its initiation decreased with increasing confining pressure, similar to the yield stress for an unnotched sample that maps out a cap with negative slope in the stress space. At the initiation stage, the asymptotic stress field in the vicinity of the notch can be evaluated using linear elastic fracture mechanics. Near the notch the stress path is approximately linear with a slope dependent only on the Poisson's ratio. The localized mean stress is significantly enhanced relative to the remote loading. Plastic yield initiates when this stress path intersects the yield cap determined for unnotched samples. From the asymptotic stress analysis, we infer that the initiation of localized yield, as indicated by a surge in acoustic emission in a notched sample, typically involves a damage zone extending from the tip to one or two grains, in agreement with our microstructural observations. Beyond initiation, compaction localization was observed to propagate differently for the two sandstones. While the bands propagated as "anti-cracks" in a direction subperpendicular to the maximum principal stress in Bentheim sandstone, they developed as conjugate bands at an angle of \\sim55° in Berea sandstone. This difference is possibly related to the different modes of localization observed in unnotched samples: Bentheim sandstone develops discrete compaction bands with episodic stress

  11. Influence of pressure, temperature, and pore fluid on the frequency-dependent attenuation of elastic waves in Berea sandstone

    Science.gov (United States)

    O'hara, Stephen G.

    1985-07-01

    The effects of pore fluid, effective stress, pore fluid pressure, and temperature on the frequency dependence of elastic wave attenuation in Berea sandstone are interrelated in a series of systematic experiments. The attenuation of both the extensional and torsional modes of cylindrical samples of the sandstone is measured on the frequency range 3-30 kHz. To simulate conditions within the earth, the sandstone is subjected to confining stress to 70.0 MPa and temperature from 24.0 °C to 120.0 °C. Confining pressure and pore fluid pressure are varied independently. Data for two different pore fluids, brine and n-heptane, suggest that a scaling law exists for the pressure and temperature dependence of the attenuation in terms of the pore fluid. The logarithmic decrement of the sandstone is almost frequency independent in a vacuum evacuated sample, but shows a linear frequency dependence, once the sample is saturated. Extrapolation of this linear trend to low frequencies suggests that the decrement in fluid-filled sandstone is effectively frequency independent at seismic frequencies (<100 Hz). The frequency dependence becomes more pronounced as either the effective stress or the temperature is decreased. When the difference between the external stress on the sandstone and the pore fluid pressure is large, the attenuation depends only on the effective stress and is relatively temperature independent. But at low effective stress, the attenuation increases linearly with increasing pore fluid pressure and decreases linearly with increasing temperature. While a specific model is lacking, the attenuation process is apparently influenced most strongly by chemical processes at the pore fluid-matrix interface accompanied by subtle changes in the sandstone matrix dimensions.

  12. Characterization and prediction of reservoir architecture and petrophysical properties in fluvial channel sandstones, middle Magdalena basin, Colombia

    International Nuclear Information System (INIS)

    About 1600 m of core from two major oil fields, and 600 m of outcrop sections near to one of the fields, integrated with thousands of core, side-wall core and outcrop porosity and permeability measurements show that petrophysical properties and reservoir continuity change consistently with the Accommodation to Sediment Supply (A/S) ratio. Channel sandstones exhibit regular, recurring motifs that are associated with changes in A/S conditions. Manifesting the lowest accommodation conditions are amalgamated channel sandstones, up to 5-m-thick, with intraclast-rich bases capped by up to 1m thick flood plain mud stones. AT higher A/S conditions, slightly amalgamated channel sandstones have lateral accretion surfaces and are capped by a thicker unit of flood plain mud stones. Channel sandstones in the highest A/S conditions are single-storied, possess conspicuous lateral accretion surfaces with thick mud drapes, and have a thick cover of over bank and flood plain deposits. Detailed well log correlations, oil production and pressure data support that the former are more lateral continuous while the latter form laterally discontinuous bodies embedded in flood plain mud stones. Petrophysical properties are closely associated with subtle variations in facies, particularly degree of preservation of original bed forms, and both are stratigraphically sensitive. Petrophysical properties of identical sedimentological facies change regularly as a function of its stratigraphic position because of variations in the rates of accumulation und degree of preservation of the sediments. In the case of fluvial strata deposited during an increase in A/S, porosity and permeability are highest in trough cross-stratified sandstones immediately above channel scour bases, und decrease upward to the next scour base. Successive channel sandstones within the same stratigraphic sequence and channel sandstones from one sequence to the next have progressively lower porosity and permeability values in

  13. Use of seasonal trend decomposition to understand groundwater behaviour in the Permo-Triassic Sandstone aquifer, Eden Valley, UK

    Science.gov (United States)

    Lafare, Antoine E. A.; Peach, Denis W.; Hughes, Andrew G.

    2016-02-01

    The daily groundwater level (GWL) response in the Permo-Triassic Sandstone aquifers in the Eden Valley, England (UK), has been studied using the seasonal trend decomposition by LOESS (STL) technique. The hydrographs from 18 boreholes in the Permo-Triassic Sandstone were decomposed into three components: seasonality, general trend and remainder. The decomposition was analysed first visually, then using tools involving a variance ratio, time-series hierarchical clustering and correlation analysis. Differences and similarities in decomposition pattern were explained using the physical and hydrogeological information associated with each borehole. The Penrith Sandstone exhibits vertical and horizontal heterogeneity, whereas the more homogeneous St Bees Sandstone groundwater hydrographs characterize a well-identified seasonality; however, exceptions can be identified. A stronger trend component is obtained in the silicified parts of the northern Penrith Sandstone, while the southern Penrith, containing Brockram (breccias) Formation, shows a greater relative variability of the seasonal component. Other boreholes drilled as shallow/deep pairs show differences in responses, revealing the potential vertical heterogeneities within the Penrith Sandstone. The differences in bedrock characteristics between and within the Penrith and St Bees Sandstone formations appear to influence the GWL response. The de-seasonalized and de-trended GWL time series were then used to characterize the response, for example in terms of memory effect (autocorrelation analysis). By applying the STL method, it is possible to analyse GWL hydrographs leading to better conceptual understanding of the groundwater flow. Thus, variation in groundwater response can be used to gain insight into the aquifer physical properties and understand differences in groundwater behaviour.

  14. 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.

  15. 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

  16. Detrital modes of the Pyeongan Supergroup (Late Carboniferous Early Triassic) sandstones in the Samcheog coalfield, Korea: implications for provenance and tectonic setting

    Science.gov (United States)

    Lee, Yong Il; Sheen, Dong-Hee

    1998-08-01

    Medium to coarse sandstones of the Carboniferous to Early Triassic Pyeongan Supergroup in the Samcheog coalfield, Korea, were studied to infer the provenance and tectonic settings of the source areas. Sandstone detrital modes change upwards stratigraphically. Sandstone types from the Manhang to Dosagog formations low to middle in the sequence are quartzarenite, and sublitharenite to litharenite, whereas sandstones of the Gohan and Donggo formations high in the sequence are feldspathic litharenite and arkose, respectively. Using various ternary diagrams, the provenance of the Manhang to Gohan formations is suggested to be a recycled orogen setting. Some Gohan Formation sandstones plot within the arc-related setting field, and the Donggo Formation sandstones plot within both continental block and recycled orogen fields. Results of quartz grain petrography are consistent with those of detrital modes. Quartz in sandstones of all units except the Donggo Formation indicates derivation from low-rank metamorphic sources. Quartz in Donggo sandstones was derived from medium- to high-rank metamorphic and plutonic source rocks. Considering the sandstone composition and palaeocurrent data, the Pyeongan Supergroup probably was deposited in a molasse foreland basin and was derived from a synbasinal orogenic belt, probably the Akiyoshi orogen located in southwest Japan.

  17. 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.

  18. 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)

  19. Laboratory experiment on poroelastic behavior of Berea sandstone under two-phase fluid flow condition

    Science.gov (United States)

    Goto, H.; Aichi, M.; Tokunaga, T.; Yamamoto, H.; Ogawa, T.; Aoki, T.

    2013-12-01

    Coupled two-phase fluid flow and deformation of Berea sandstone was discussed through laboratory experiments and numerical simulation. In the experiment, a triaxial compression apparatus with flow pipes to pass fluids through a rock sample was used. The experimental procedures were as follows. Firstly, external stresses close to hydrostatic condition were applied to a water saturated cylindrical Berea sandstone sample. Then, compressed air was infiltrated from the bottom of the sample. During the experiment, both axial and circumferential strains at half the height of the sample and volumetric discharge of water at the outlet were measured. Both strains showed sudden extensions after a few seconds, and monotonically extended thereafter. The volumetric discharge of water showed that air breakthrough occurred in around 100 seconds after the commencement of the air injection. Numerical simulations based on thermodynamically consistent constitutive equations were conducted in order to quantitatively analyze the experimental results. In a simulation in which the material was assumed to be homogeneous isotropic, the axial strain at half the height of the sample and the volumetric discharge of water at the outlet were reproduced well by using reasonable parameters, while that was not the case with the circumferential strain at half the height of the sample. On the other hand, in a simulation in which anisotropy of the material was introduced, all experimental data were reproduced well by using reasonable parameters. This result is reasonable because Berea sandstone is well known to be anisotropic under such Terzaghi effective stress condition as used in our experiment, i.e., 3.0 MPa (Hart and Wang, 1999; Hart, 2000). Our results indicate that the theory of poroelasticity for two-phase fluid system can explain the strain behavior of porous media for two-phase fluid flow observed in laboratory experiments.

  20. A magnetic resonance study of pore filling processes during spontaneous imbibition in Berea sandstone

    Science.gov (United States)

    Chen, Quan; Gingras, Murray K.; Balcom, Bruce J.

    2003-11-01

    A new magnetic resonance technique, DDIF (the decay of magnetization due to diffusion in the internal field), was combined with mercury porosimetry to investigate pore geometry, including pore- and throat-size distribution, and pore connectivity for porous media. A comparison of DDIF spectra for a fully water saturated Berea sandstone, with the partially saturated sample by centrifugation in air, indicated that DDIF can be used for the measurement of water filled pore size distribution in partially saturated porous media. Dynamic water imbibition into air-filled Berea sandstone was studied using the DDIF technique. Simultaneously, in situ three-dimensional saturation and capillary driven water penetration were monitored using Conical-SPRITE, which is a rapid, centric scanning, spin-density weighted single point three-dimensional magnetic resonance imaging technique. These measurements provide direct evidence for differences in the pore filling mechanisms for co-current imbibition and counter-current imbibition in Berea sandstone. During co-current imbibition, water flows through the pores and connected throats with a piston-type mechanism. Air is displaced from the sample by the leading edge of the waterfront, resulting in a macroscopic piston-like flow through the entire sample. During counter-current imbibition, water flows through the pores and connected throats with a film-like structure along the corners and surfaces of the pore space. Air escapes from the sample by flowing through the center of the pores and pore throats, in the opposite direction. Once the penetrating waterfronts meet, at the sample center, there is a global, uniform increase in water content.

  1. Research and application of information system for sandstone-type uranium exploration

    International Nuclear Information System (INIS)

    The GIS (Geographical Information System) technique is applied to the exploration and evaluation of in-situ leachable sandstone-type uranium deposits and the GIS application system of desktop is created for non-GIS professionals. ArcView3.2 is taken as compositive platform of the information system. The secondary design is developed through the AVENUE language provided by ArcView3.2 on the software functions. According to the needs of multi-source information management and integrated evaluation, a series of new functions are appended to the basic platform through AVENUE language on a basis of sufficiently inheriting ArcView3.2 software functions and a friendly graphic user interface is also created, so that the system implements the following functions better, including information query, data base management, editing graphics, geologic mapping, image processing, spatial analysis, model analysis and result output. In order to manage the plenty of borehole data better and quickly realize the borehole mapping, a system software of borehole data management and mapping on the base of GIS software platform is developed. The system software has been applied to uranium survey project in the west of Hailaer basin. Based on multi-source geoscience information database including geologic, geophysical, geochemical and remote sensing data, the system software has been used to perform the integrated analysis of spatial data for realizing the deep analysis and studies of the metallogenic geologic environments of sandstone-type uranium deposits. In the Kelulun basin, the weights of evidence analysis have been used to quantitatively predict the prospective areas of sandstone uranium deposits. Information system has also been applied to the integrated evaluation of uranium resource in the south of Yili basin, Songliao basin and other areas. (authors)

  2. 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

  3. 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.

  4. Sandstone geometry, porosity and permeability distribution, and fluid migration in eolian system reservoirs

    Science.gov (United States)

    Lupe, Robert; Ahlbrandt, Thomas S.

    1975-01-01

    Upper Paleozoic to Mesozoic eolian blanket sandstones of the Colorado Plateau and the Rocky Mountains of Colorado and southern Wyoming are texturally complex. As petroleum reservoirs they commonly have poor performance histories. They contain the sediments of a depositional system comprised of three closely associated depositional subenvironments: dune, interdune, and extradune. Sediments of each subenvironment have different textural properties which resulted from different depositional processes. Dune sediments are usually more porous and permeable than interdune or extradune sediments and may be better quality reservoirs than interdune or extradune sediments. Interdune sediments are here restricted to those nondune sediments deposited in the relatively flat areas between dunes. Extradune sediments (a new term) include all deposits adjacent to a dune field and are mainly subaqueous deposits. Dune sediments may be enveloped by extradune sediments as the depositional system evolves resulting in a texturally inhomogeneous reservoir having poor fluid migration properties. This model of textural inhomogeneity in eolian blanket sandstones. was applied to the Weber (Tensleep) Sandstone in Brady, Wertz, and Lost Soldier fields, Sweetwater County, Wyoming. Data were obtained from both outcrop and subsurface and included environmental interpretation, textural analysis, and plotting of the distribution of depositional subenvironments. As predicted from the model, the texture of dune sediments in Brady field differed markedly from interdune and extradune sediments. The predicted geometric distribution of subenvironments was confirmed in Lost Soldier and Wertz fields. However, secondary cementation and fracturing there has obscured the original porosity and permeability contrasts. The porosity and permeability distribution, a characteristic depending partly on depositional processes, could impede fluid migration in the reservoir and significantly reduce recovery of

  5. 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.

  6. Origin of northern Gondwana Cambrian sandstone revealed by detrital zircon SHRIMP dating

    Science.gov (United States)

    Avigad, D.; Kolodner, K.; McWilliams, M.; Persing, H.; Weissbrod, T.

    2003-01-01

    Voluminous Paleozoic sandstone sequences were deposited in northern Africa and Arabia following an extended Neoproterozoic orogenic cycle that culminated in the assembly of Gondwana. We measured sensitive high-resolution ion microprobe (SHRIMP) U-Pb ages of detrital zircons separated from several Cambrian units in the Elat area of southern Israel in order to unravel their provenance. This sandstone forms the base of the widespread siliciclastic section now exposed on the periphery of the Arabian-Nubian shield in northeastern Africa and Arabia. Most of the detrital zircons we analyzed yielded Neoproterozoic concordant ages with a marked concentration at 0.55–0.65 Ga. The most likely provenance of the Neoproterozoic detritus is the Arabian-Nubian shield; 0.55–0.65 Ga was a time of posttectonic igneous activity, rift-related volcanism, and strike-slip faulting there. Of the zircons, 30% yielded pre-Neoproterozoic ages grouped at 0.9–1.1 Ga (Kibaran), 1.65–1.85 Ga, and 2.45–2.7 Ga. The majority of the pre-Neoproterozoic zircons underwent Pb loss, possibly as a consequence of the Pan-African orogeny resetting their provenance. Rocks of the Saharan metacraton and the southern Afif terrane in Saudi Arabia (∼1000 km south of Elat) are plausible sources of these zircons. Kibaran basement rocks are currently exposed more than 3000 km south of Elat (flanking the Mozambique belt), but the shape of the detrital zircons of that age and the presence of feldspar in the host sandstone are not fully consistent with such a long-distance transport. Reworking of Neoproteorozoic glacial detritus may explain the presence of Kibaran detrital zircons in the Cambrian of Elat, but the possibility that the Arabian-Nubian shield contains Kibaran rocks (hitherto not recognized) should also be explored.

  7. Remote detection of fluid-related diagenetic mineralogical variations in the Wingate Sandstone at different spatial and spectral resolutions

    Science.gov (United States)

    Okyay, Unal; Khan, Shuhab D.

    2016-02-01

    Well-exposed eolian units of the Jurassic system on the Colorado Plateau including the Wingate Sandstone, show prominent color variations throughout southeastern Utah due to diagenetic changes that include precipitation and/or removal of iron oxide, clay, and carbonate cement. Spatially variable characteristic diagenetic changes suggest fluid-rock interactions through the sandstone. Distinctive spectral signatures of diagenetic minerals can be used to map diagenetic mineral variability and possibly fluid-flow pathways. The main objective of this work was to identify characteristic diagenetic minerals, and map their spatial variability from regional to outcrop scale in Wingate Sandstone exposures of Lisbon Valley, Utah. Laboratory reflectance spectroscopy analysis of the samples facilitated identification of diagnostic spectral characteristics of the common diagenetic minerals and their relative abundances between altered and unaltered Wingate Sandstone. Comparison of reflectance spectroscopy with satellite, airborne, and ground-based imaging spectroscopy data provided a method for mapping and evaluating spatial variations of diagenetic minerals. The Feature-oriented Principal Component Selection method was used on Advanced Spaceborne Thermal Emission and Reflection Radiometer data so as to map common mineral groups throughout the broader Wingate Sandstone exposure in the area. The Minimum Noise Fraction and Spectral Angle Mapper methods were applied on airborne HyMap and ground-based hyperspectral imaging data to identify and map mineralogical changes. The satellite and airborne data showed that out of 25.55 km2 total exposure of Wingate Sandstone in Lisbon Valley, unaltered sandstone cover 12.55 km2, and altered sandstone cover 8.90 km2 in the northwest flank and 5.09 km2 in the southern flank of the anticline. The ground-based hyperspectral data demonstrated the ability to identify and map mineral assemblages with two-dimensional lateral continuity on near

  8. 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

  9. Conditional evaluation of sandstone uranium deposits by in-situ leaching

    International Nuclear Information System (INIS)

    The in-situ leaching is a new advanced technology of mining uranium, being used to mining exogenetic and xenogenous unconsolidated sandstone uranium deposits. Properly geologic and hydrogeologic conditions are the prerequisite successfully using it. The author describes the affection of ore deposit conditions on the technical-economy of in-situ leaching uranium, including the ore permeability, the ore-bearing aquifer framework, the quality of groundwater, ore material composition, the URUA (uranium reserves in the unit area, kg/m2), the occurrence feature of ore body, the associated useful element, the existent form and occurrence state of uranium in ore, and etc

  10. Uranium mineralization in the Lower Mahadek Sandstones of Laitduh Area, East Khasi Hills District, Meghalaya

    International Nuclear Information System (INIS)

    Significant uranium mineralization hosted in feldspathic sandstone of Upper Cretaceous Lower Mahadek Formation has been located at Laitduh, East Khasi Hills district, Meghalaya. Two mineralized horizons have been identified within Lower Mahadek Formation with vertical separation of 30 m. Samples from upper horizon have assayed upto 0.17% U3O8, whereas samples from lower mineralized horizon have assayed upto 0.50% U3O8. The radioactive minerals identified are coffinite and pitchblende occurring in association with carbonaceous matter. (author)

  11. 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., Jr.; 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.

  12. Estimation of minimum specifications for economically explorable sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    In this paper a method is developed for estimating the specifications of sandstone-type uranium deposits which will be the minimum that can meet a company's economic requirements for investment. The method is based on net present value analysis. From available cost data and deposit specifications for typical mines, the method involves calculating the uranium oxide selling price necessary for a mining project based on the deposit to achieve the company's required discounted cash flow rate of return on investment. A major portion of the paper is devoted to discussion of the variations of costs with the depth and thickness of uranium ore deposits. 21 refs

  13. 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

  14. Ancient sandstone condition assessment in relation to degradation, cleaning and consolidation phenomena

    Science.gov (United States)

    Drdácký, Miloš; Frankeová, Dita; Slížková, Zuzana

    2015-04-01

    Non-invasive methods for assessing the state of historic stone types rely on measurement of their surface or subsurface characteristics, which are supposed to correlate with objective physical characteristics. Such measurements are influenced by surface conditions of stone, as well as by previous conservation treatments. The authors performed a comprehensive study of characteristics and behaviour of typical sandstone types present in the Charles' Bridge in Prague as a preparatory work for its diagnostic and restoration in order to understand the problem of a large, important, and non-homogeneous (from the material point of view) historic structure, that was intended for repair interventions. The study itself took advantage of the combination of non-invasive, or considerately destructive methods and fully destructive tests, because it was possible to use damaged sandstone blocks, which were extracted from a masonry rail of the bridge before replacement with new elements. Stone characteristics were studied on test specimens prepared from materials in various conditions and after various interventions. Seven types of sandstone were tested in nine sets (degraded surface layer with a crust, degraded surface layer after cleaning, and unweathered core material; all three without any consolidation treatment, and all three after consolidation with two products based on silicic acid ester - Funcosil 100 and 300). The paper will present only selected results of experiments and the most important conclusions taken from the tests and their comparison. During experimental work the following characteristics were investigated: bending strength, modulus of elasticity, ultrasonic velocity, micro-drilling resistance, water uptake, porosity, frost resistance, hydric dilation and thermal dilation. The degraded stone had a rather strong variation of its characteristics along the depth profile from the surface inside the stone ashlar. Therefore, the stone samples were prepared in a form

  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. Relative permeability and trapping of CO2 and water in sandstone rocks at reservoir conditions

    Science.gov (United States)

    Krevor, Samuel C. M.; Pini, Ronny; Zuo, Lin; Benson, Sally M.

    2012-02-01

    We report the results of an experimental investigation into the multiphase flow properties of CO2 and water in four distinct sandstone rocks: a Berea sandstone and three reservoir rocks from formations into which CO2 injection is either currently taking place or is planned. Drainage relative permeability and residual gas saturations were measured at 50°C and 9 MPa pore pressure using the steady state method in a horizontal core flooding apparatus with fluid distributions observed using x-ray computed tomography. Absolute permeability, capillary pressure curves, and petrological studies were performed on each sample. Relative permeability in the four samples is consistent with general characteristics of drainage in strongly water-wet rocks. Measurements in the Berea sample are also consistent with past measurements in Berea sandstones using both CO2/brine and oil/water fluid systems. Maximum observed saturations and permeabilities are limited by the capillary pressure that can be achieved in the experiment and do not represent endpoint values. It is likely that maximum saturations observed in other studies are limited in the same way and there is no indication that low endpoint relative permeabilities are a characteristic of the CO2/water system. Residual trapping in three of the rocks is consistent with trapping in strongly water-wet systems, and the results from the Berea sample are again consistent with observations in past studies. This confirms that residual trapping can play a major role in the immobilization of CO2 injected into the subsurface. In the Mt. Simon sandstone, a nonmonotonic relationship between initial and residual CO2 saturations is indicative of a rock that is mixed or intermediate wet, and further investigations should be performed to establish the wetting properties of illite-rich rocks. The combined results suggest that the petrophysical properties of the multiphase flow of CO2/water through siliciclastic rocks is for the most part typical

  17. STRUCTURAL HETEROGENEITIES AND PALEO FLUID FLOW IN AN ANALOG SANDSTONE RESERVOIR 2001-2004

    International Nuclear Information System (INIS)

    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

  18. The application of uranium isotopes to the study of sandstone type uranium deposits

    International Nuclear Information System (INIS)

    Based on the study of composition of uranium isotopes in deposits No.512, the composition distribution of uranium isotope for the uranium deposits of sandstone type are discussed. According to the distribution of uranium isotope samples in different oxidation-reduction zones, the region A should be named as the region of geochemical conflict. The distribution of uranium isotope composition is not only can be used to predict the location of uranium ore body, but also can be used to study the rolling of the roll during the process of the ore body formation. (authors)

  19. 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

    seismic resolution is inadequate for architectural analysis. Description of the reservoir sandstone bodies is thus based on sedimentological interpretation and correlation of seven wells, of which five were cored. Palaeotopography played a major role in the position and preservation of the thick reservoir...... last c. 8000 years 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...

  20. 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

  1. 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.

  2. Pore-throat size distributions in Permo-Triassic sandstones from the United Kingdom and some implications for contaminant hydrogeology

    Science.gov (United States)

    Bloomfield, J. P.; Gooddy, D. C.; Bright, M. I.; Williams, P. J.

    2001-06-01

    Pore-throat size distributions (PSDs) from mercury injection capillary pressure (MICP) tests have been used to characterise 153 samples of Permo-Triassic sandstones from the United Kingdom. The PSDs have been parameterised using the Brooks-Corey and van Genuchten functions. Pore-throat sizes are in the range 0.01-427 µm, and dominant pore-throat sizes range from about 0.1-90 µm. Values of λ, the Brooks-Corey pore-size distribution index, range from 0.002-2.27, and values of m, the van Genuchten pore-size distribution index, range from 0.03-0.92. A number of classes of sandstone can be recognised on the basis of trends in the fitted parameters. The van Genuchten function provides the most effective method for classifying different sandstones. Additionally, a cross-plot of gas permeability against displacement pressure (derived from the van Genuchten function) shows that the data fall into two distinct sub-populations. The frequency distribution of a larger population of sandstone permeabilities can be modelled using the mean and standard deviation of the two sub-populations identified in the MICP study, assuming that the sub-populations are approximated by log-normal distributions. The distribution of sandstones with small pore-throat sizes is critical to the fate of pathogens and immiscible phase contaminants in the aquifer.

  3. 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.

  4. 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.

  5. Comparison of metallogenic conditions for sandstone-type uranium deposit between Erlian basin of China and sedimentary basins of Mongolia

    International Nuclear Information System (INIS)

    Based on the study of metallogenic background and basic metallogenic characteristics,this paper summarizes the main ore-controlling factors of sandstone-type uranium deposits in Erlian basin of China and basins in southeastern Mongolia with the theory of sandstone-type uranium metallogeny,and systematically analyses similarities and differences between the two areas. The general similarities of tectonic attribute, basin type and scale, uranium source, and tectonic evolution in both areas are proposed in this paper, and also their obvious differences in uranium-hosting strata, late tectonic activity and regional uranium mineralization occurrences, especially in tectonic activity and ore-controlling sedimentary system are proposed. The authors believe that the two areas have approximate uranium-productive potentialities, and propose the importence of prospecting 'Sumin-river model' sandstone-type uranium deposit in Erlian basin in the future. (authors)

  6. Geological characteristics and prospecting potential of sandstone-type uranium deposits in the north margin of Qaidam basin

    International Nuclear Information System (INIS)

    The north margin of Qaidam Basin is composed with rift trough and Oulongbuluke landmass which is clamped by Qilian Mountain and Qaidam block Suture zone. The two activities provide a rich source of uranium for the basin area. The coal-bearing rocks as stratums of medium and lower Jurassic, is the main exploration target zones of sandstone-type uranium ore. Through geological survey and drilling, we think that the interlayer oxidation zone. being primary factors of sandstone-type uranium, can be divided into ancient type and modern type. The ancient interlayer oxidation zone type uranium deposit is the main prospecting types in the north margin of Qaidam Basin. Combined with analysis on geological conditions of sandstone-type uranium mineralization, we propose that eastern edge of Yuqia, southern edge of Lucao Mountain, Beidatan and northwest edge of Ulan depression are good prospects. (authors)

  7. New understanding of ore-formation of in-situ leachable sandstone-type uranium deposit in Erlian basin

    International Nuclear Information System (INIS)

    Starting with the ore-controlling role of tectonic evolution of Erlian basin, i.e. the basement evolution stage, the formation state of ore-hosting formation, and the ore-formation stage of epigenetic reworking, authors come to a conclusion, that Erlian basin was a sedimentary basin composed of tens of little separate depressions with their own tectonic and sedimentary evolutionary features, and multiple and near source area at the stage of the ore-hosting formation. Combining above-mentioned factors with the other ore-controlling factors related to sandstone-type uranium deposits, authors suggest that the size of sandstone-type uranium deposits to be found in Erlian basin might be mostly small or medium in size. Bu it is possible that the smaller medium-sized uranium deposits would occur in groups. The dominant subtype of the sandstone-type uranium deposits may be phreatic-interlayered oxidized zone

  8. 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.

  9. 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.

  10. An experimental study on seepage behavior of sandstone material with different gas pressures

    Science.gov (United States)

    Yang, Sheng-Qi; Huang, Yan-Hua; Jiao, Yu-Yong; Zeng, Wei; Yu, Qing-Lei

    2015-12-01

    The seepage evolution characteristic of brittle rock materials is very significant for the stability and safety of rock engineering. In this research, a series of conventional triaxial compression and gas seepage tests were carried out on sandstone specimens with a rock mechanics servo-controlled testing system. Based on the experimental results, the relationship between permeability and deformation is firstly analyzed in detail. The results show that the permeability-axial strain curve can be divided into the following five phases: the phase of micro-defects closure, the phase of linear elastic deformation, the phase of nonlinear deformation, the phase of post-peak stress softening and the phase of residual strength. The seepage evolution characteristic is also closely correlated with the volumetric deformation according to the relationship between permeability and volumetric strain. It is found that the gas seepage pressure has a great effect on the permeability evolution, i.e. permeability coefficients increase with increasing gas seepage pressures. Finally, the influence of gas seepage pressures on the failure behavior of brittle sandstone specimens is discussed.

  11. Mechanism of formation of wiggly compaction bands in porous sandstone: 1. Observations and conceptual model

    Science.gov (United States)

    Liu, Chun; Pollard, David D.; Deng, Shang; Aydin, Atilla

    2015-12-01

    Field observations are combined with microscopic analyses to investigate the mechanism of formation of wiggly compaction bands (CBs) in the porous Jurassic aeolian Aztec Sandstone exposed at Valley of Fire State Park, Nevada. Among the three types of CBs (T1, T2, and T3), we focused on the wiggly CBs (T3), which show a chevron (T31) or wavy (T32) pattern with typical corner angles of approximately 90° or 130°, respectively. Where corner angles of wiggly CBs increase to 180°, they become straight CBs (T33). Image analyses of thin sections using an optical microscope show host rock porosity increases downslope in this dune, and the predominant type of wiggly CBs also varies from chevron to straight CBs. Specifically, band type varies continuously from chevron to wavy to straight where the porosity and grain sorting of the host rock increase systematically. Based on the crack and anticrack models, we infer that the change from chevron to straight CBs is due to increasing failure angle of the sandstone and this may correlate with increasing grain sorting. Wavy CBs with intermediate failure angle and host rock porosity are an intermediate stage between chevron and straight CBs. Previous sedimentological studies also have suggested that grain size and sorting degree increase downslope on the downwind side of sand dunes due to a sieving process of the wind-blown grains. Therefore, the transition of wiggly CB types in this regard correlates with increasing sorting and perhaps with increasing porosity downslope.

  12. 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.

  13. Permeability variations in Berea and Vosges sandstone submitted to cyclic temperature percolation of saline fluids

    Energy Technology Data Exchange (ETDEWEB)

    Baudracco, J.; Aoubouazza, M. [Universite Paul Sabatier, 31 - Toulouse (France)

    1995-10-01

    The behaviour has been examined of two samples of Berea and Vosges sandstones submitted to the circulation of solutions of different natures, at different temperatures. Solutions of CaCl{sub 2} and NaCl at ionic strengths I=0.01, I=0.1 and I=1, taken in the increasing and then decreasing directions, were heated to temperatures of 20, 30, 40, 50, 60, 70, 80 and 90{sup o}C. These temperatures were taken in the increasing and then decreasing directions. For the two sandstones, each temperature variation in the percolating solution was accompanied by a sharp variation in permeability, in the opposite direction to the temperature variation. The permeability versus temperature variation describes hysteresis loops whose area is greater when hot than when cold. These curves are typical of two types of behaviour. The first is obtained with diluted solutions (I=0.01 and I=0.1), and is characterized by a greater permeability during the rising temperature cycle than during the decreasing temperature cycle. The second, obtained with concentrated solutions, is characterized by an inverse variation; the permeability is greater during the decreasing temperature cycle than during the rising cycle. These different behaviours are interpreted in terms of flocculation-deflocculation of the clays contained in the porous media. (Author)

  14. Anomalous Thermal Relaxation Induced by the Granular Composition of Berea Sandstone

    Science.gov (United States)

    Ulrich, T.; McCall, K. R.; Guyer, R.

    2003-12-01

    Berea sandstone is a well-studied material known to be nonlinearly elastic. For example, stress-strain measurements for stresses less than 30 MPa are repeatably hysteretic and display end-point memory. In an effort to understand the energy scales of the mechanisms causing nonlinear elasticity in Berea sandstone, we have studied the temperature dependence of sample resonances. Resonances are related to the elastic moduli of a sample, and thus indicate whether or not a sample is hardening or softening as a function of temperature. We find that for temperatures in the range 100 K -- 330 K, sample resonance frequencies display significant hysteresis, and several unusual behaviors. Elastic softening is observed as temperature decreases, rather than the expected monotonic increase. In addition, while measurements are repeatable, they are rate dependent on a timescale much longer than the calculated timescale for temperature equilibrium across the sample. It is our hypothesis that this unusual elastic behavior and the slow onset of thermal equilibrium arises from the granular nature of the material. A series of time and temperature dependent experiments was designed and executed to investigate this hypothesis. We will discuss the results of these measurements and their implications for future research.

  15. Shear wave velocity and attenuation from pulse-echo studies of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Green, D.H. [Ohio Univ., Athens, OH (United States); Wang, H.F. [Univ. of Wisconsin, Madison, WI (United States)

    1994-06-10

    The pulse-echo spectral-ratio technique has been adapted to the determination of ultrasonic shear wave attenuation in sandstone at variable states of saturation and pressure. The method can measure shear attenuation coefficients in the range 0.5 dB/cm to 8 dB/cm to within {+-}0.5 dB/cm. For the Berea sandstone, this range corresponds to values of the shear quality factor (Q{sub s}) between 10 and 100. Spectra of Q{sub s} show that between 600 and 1100 kHz, Q{sub s} decreases with frequency, particularly at high pressures (up to 700 MPa). Ultrasonic shear wave attenuation in a 90% water-saturated sample was intermediate between that for dry samples and the relatively high attenuation in fully saturated rock. Strong pressure dependence is seen in the shear attenuation for all saturation states, indicating a dominant role of dissipation mechanisms operating within open and compliant cracks. Substantial shear attenuation remains at the highest effective pressure applied to the saturated sample, which may be due to a more {open_quotes}global{close_quotes} fluid-flow loss mechanism. Scattering losses, as described by weak scattering theories for compressional waves, do not appear to be dominant at these frequencies. 46 refs., 9 figs.

  16. 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. PMID:16346974

  17. Thickness trends and structure of Berea Sandstone (Mississippian) in Washington County, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarone, M.; Norton, W.

    1985-02-01

    The Berea Sandstone has been a drilling target for hydrocarbon production in Ohio for over 100 yr. Although extensively produced, the Berea still rewards the driller with new commercial production. Due to its shallow depth and low cost of completion, the Berea has undergone a renaissance in interest in recent years. This paper presents the results of a study of more than 3500 geophysical and driller's logs in Washington County in southeastern Ohio. Structure contours show major trends, such as the Burning Springs anticline and the Cambridge arch, trending almost north-south. In the western third of the county, structural trends change, however, to a more complex, less continuous pattern with a predominant northeast-southwest trend. Isopach trends delineate a system of channel sands trending roughly east-west with sandstone thicknesses ranging from 0 to greater than 25 ft (8 m). Both structures and thalwegs are relatively narrow and thickness changes rapidly, both parallel to and normal to the thalweg. Although no new interpretations of Berea structure or depositional environment is intended, this study graphically shows that even in a mature province, low-cost, closely spaced data can indicate new minor structures and delineate new areas for profitable and productive testing with the drill.

  18. A constitutive model for stress-induced permeability and porosity evolution of Berea sandstone

    Science.gov (United States)

    Morris, J. P.; Lomov, I. N.; Glenn, L. A.

    2003-10-01

    Many applications in geophysics require good estimates of permeability evolution in response to deformation, pore collapse, dilatancy, and microfracturing. Simulations of the upper crust, oil well completion, and nuclear waste repositories depend upon reliable predictions of changes in rock permeability. For some applications, permeability can affect the strength of rock by influencing the pore pressure and effective stress. For example, the pore pressure during production from an oil bearing formation is controlled by the evolving permeability field. The rock strength, however, depends upon the effective stress which is influenced by the pore pressure. Accurate prediction of possible failure in such formations requires reliable estimates of permeability change. Ideally, such estimates could be obtained by directly simulating the changes in pore space connectivity at the microscale. In practice the system being studied is sufficiently large that constitutive models must be developed which address permeability evolution macroscopically. We develop a model for predicting porosity and permeability changes in Berea sandstone. The model has been kept as simple as possible in order to facilitate incorporation of the model into existing mechanics codes. For this reason we assume the existence of a separate material model capable of predicting the stress-strain response of the rock. In addition, the model assumes that the original pores and pores created by microfracturing can be treated separately with respect to permeability and porosity evolution. Despite these simplifying assumptions, the model is able to reproduce most of the key features observed in previously reported triaxial experiments performed on Berea sandstone.

  19. Linear and nonlinear modulus surfaces in stress space, from stress-strain measurements on Berea sandstone

    Science.gov (United States)

    Boudjema, M.; Santos, I. B.; McCall, K. R.; Guyer, R. A.; Boitnott, G. N.

    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.

  20. Effect of sterilization by dry heat or autoclaving on bacterial penetration through Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    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/sup 0/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.

  1. Lithologic and environmental atlas of Berea Sandstone (Mississippian) in the Appalachian Basin

    Science.gov (United States)

    Potter, P. E.; Maynard, J. B.; Jackson, D.; Dereamer, J.

    1984-01-01

    The Berea Sandstone occurs throughout much of the Appalachian Basin where it is an oil and gas reservoir and is quarried as a building stone. Because of its uniform porosity and permeability in the quarries at South Amherst, Ohio, it has been used by petroleum engineers in North America as a model reservoir sandstone. Currently, the Berea is locally classified as a light gas sand. Six outcrops and 22 cores of the Berea are described. These descriptions are accompanied by wireline logs of the Berea section in the core holes and gamma ray profiles of outcrops to help explorationists, reservoir geologists, and petroleum engineers better interpret the lithology and depositional environments represented by the many thousands of wireline logs in the Applachian Basin. The depositional environments likely to occur in the Berea are briefly described and the various sedimentary structures of the Berea are illustrated so that it can be seen in both outcrops and cores, carefully documents vertical profiles of grain size and sedimentary structures, and concludes with a summary of unresolved problems.

  2. The influence of texture on steady foam flow in Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Ettinger, R.A.; Radke, C.J.

    1989-10-01

    We have studied the quantitative role of bubble size in the steady flow of strong foam through a 0.8-{mu}m{sup 2} Berea sandstone. Inlet and outlet textures are determined from photomicrographs taken of bubbles flowing through specially designed visual cells. Concurrent measurements of pressure profiles and liquid saturation profiles by microwave attenuation are acquired for gas velocities ranging from 1 to 3 m/day and covering a foam quality range from 70 to 90%. At steady state, liquid saturations remain constant near 35% independent of gas velocity. Moreover, measured foam-flow resistances practically do not vary with gas velocity over the studies range. Foam textures, however, do vary dramatically. For example, injected fine bubbles near 80 {mu}m in diameter exit the sandstone with sizes around 300 {mu}m. Powerful coalescence forces are the origin of this coarsening. Effluent bubble sizes increase slightly with increasing gas velocity, but are independent of the injected size. A simple one-dimensional foam population-balance model is outlined to quantify the observed flow and texture behavior. At steady state, generation and coalescence mechanisms alter the foam texture over distances of less than about a centimeter. 31 refs., 12 figs., 1 tab.

  3. Stratigraphic and structural controls of natural gas production from the Berea Sandstone (Mississippian), southwestern Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Nolde, J.E. (Virginia Division of Mineral Resources, Charlottesville, VA (United States)); Milici, R.C. (Geological Survey, Denver, CO (United States))

    1993-08-01

    The Berea Sandstone, a major reservoir 5000 ft beneath the Virginia plateau, produces nonassociated gas, from west to east, from the Roaring Fork, Nora, Glick, and Berwind trends. Production generally is stratigraphically controlled, but may be structurally enhanced in the Berwind trend on the southwest-plunging Dry Fork anticline. The Berea is within a shale sequence and grades generally from sandstone to siltstone westward. Production in Roaring Fork coincides approximately with relatively small areas of slightly greater siltstone thickness. The Nora and Glick trends, major northeast-extending zones as much as 150 and 60 ft thick, respectively, are 14 mi apart, 10 mi across, and up to 30 mi long. These trends are parallel to the Mississippian paleoshoreline and contain prodelta sediments that accumulated at or below wave base. In the Nora trend, the Berea produces where it is greater than 60 ft thick. Initial well-head pressures generally range from 500 to 800 lb/in[sup 2], and final open flows commonly range up to 1400 MCFD, with the maximum reported as 4992 MCFD. Eastward toward the source of sediment, as little as 40 ft of Berea produce gas in the Glick and Berwind fields. Initial open flows increase eastward, reflecting increases in grain size, porosity, permeability, and perhaps in fractures. In the Nora trend, natural open flows for 10% of the wells exceed 150 MCFD; in the Glick and Berwind fields, open flows for 30 and 60% of the wells, exceed 150 MCFD.

  4. Shear wave velocity and attenuation from pulse-echo studies of Berea sandstone

    Science.gov (United States)

    Green, Douglas H.; Wang, Herbert F.

    1994-06-01

    The pulse-echo spectral-ratio technique has been adapted to the determination of ultrasonic shear wave attenuation in sandstone at variable states of saturation and pressure. The method can measure shear attenuation coefficients in the range 0.5 dB/cm to 8 dB/cm to within +/- 0.5 dB/cm. For the Berea sandstone, this range corresponds to values of the shear quality factor Q(sub s) between 10 and 100. Spectra Q(sub s) show that between 600 and 1110 kHz, Q(sub s) decreases with frequency, particularly at high pressures (up to 70 MPa). Ultrasonic shear wave attenuation in a 90% water-saturated sample was intermediate between that for dry samples and the relatively high attenuation in fully saturated rock. Strong pressure dependence is seen in the shear attentuation for all saturation states, indicating a dominant role of dissipation mechanisms operating within open and compliant cracks. Substantial shear attenuation remains at the highest effective pressure applied to the saturated sample, which may be due to a more 'global' fluid-flow loss mechanism. Scattering losses as described by weak scattering theories for compressional waves, do not appear to be dominant at these frequencies.

  5. Role of Some Isolated Fungi in The Biological Leaching of Uranium From Low Grade Cretaceous Sandstone

    International Nuclear Information System (INIS)

    Microbiological leaching has been used as an alternative approach to conventional hydrometallurgical methods of uranium extraction. In this investigation, the biological leaching of uranium by isolated fungi from low grade sandstone was studied. Five isolates of fungi were obtained from sandstone sample. Cladosporium oxysporum and Penicilluim stoloniferum exhibited high potential in generating a variety of organic acids effective for uranium extraction. The percentages of organic acid produced by fungi were determined. By-product such as molasses was tested. The maximum dissolution of uranium was achieved at the following conditions; incubation period 6 days, pulp density 1:3 g/L, ph 3.5 and at 30 degree C. Maximum solubilization of uranium with values of 54% and 67% were achieved by Cladosporium oxysporum and Penicilluim stoloniferum, respectively. From properly prepared pregnant bio-leach liquor, the leached uranium was recovered in the form of marketable products (3UO3NH3 .5H2O) using classical chemical technique and the product was confirmed using XRD techniques

  6. 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.

  7. Mixed marine and lacustrine input to an oil-cemented sandstone breccia from Brora, Scotland

    Energy Technology Data Exchange (ETDEWEB)

    Peters, K.E. [Mobil Exploration and Producing Technical Center, Dallas, TX (United States); Clutson, M.J. [Mobil North Sea Ltd., Aberdeen (United Kingdom); Robertson, G. [Mobil New Exploration and Producing Ventures, Dallas, TX (United States)

    1999-07-01

    A rounded cobble collected from a beach near Brora, Scotland, contains angular, brecciated sandstone clasts cemented together by crude oil. No oil occurs within the tight, dolomite-cemented clasts, except along fractures. Provenance of the cobble is uncertain, however, the lithology and shape of the clasts suggests that they are fault gouge breccia composed of Old Red Sandstone from the nearby Helmsdale Fault. Oil emplacement, presumably along the fault, cemented the breccia prior to transport and weathering of the cobble. Independent source and biodegradation parameters support mixing of two charges of oil. Like oil from the nearby Beatrice Field, the oil cement contains 24-n-propylcholestanes and {beta}-carotene that indicate marine and lacustrine source rocks, respectively. The oil cement also contains pristane, phytane, residual n-alkanes and a complete series of 25-norhopanes, which indicate mild and heavy biodegradation respectively. The first charge consisted of lacustrine Devonian oil that was heavily biodegraded at shallow depth. The origin of the second charge is unclear. (author)

  8. 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.

  9. Petrophysical and sedimentological evaluation of the Tertiary sandstones of Barua-Motatan, Eastern Zulia

    Energy Technology Data Exchange (ETDEWEB)

    Carmona, R.; Mederos, S. [Maraven S.A., Caracas (Venezuela)

    1996-08-01

    The combined application of conventional well logs such as resistivity, gamma ray, neutron density and sonic, and specialized logs such as acoustic image and analysis of fluid and rotary coring tool samples are excellent means of evaluating reservoir rock quality, fluid saturations, and hole conditions. This paper describes the application of such a technique and presents the results thereof of reservoir characterization as applied to an exploration well PAA-1X in the eastern coast of the Maracaibo Lake, Venezuela. The PAA-1X well was drilled on the flank of a monocline west of Mene Grande fault near the border of Mene Grande field to explore the Misca Formation of Eocene age. Intermediate and Basal Pauji sandstones were not present in PAA-1X well, contrary to our expectations. The similarity of well logs and geological columns with an earlier exploration well, Tom-3X, confirmed this finding. The sandstones are medium to fine grained, with porosities of 5-21% and permeabilities of 0.02-0.8 md. The acoustic image log shows an ovalness of the hole, a characteristic typical of silty and shaly formations. The interpretation with the aforementioned tools indicates that the exploratory well has very few thin productive intervals and is therefore likely to be deemed uneconomic. This is corroborated by the DST of the upper part of the Misoa Formation that produced only water. The study does indicate that this set of tools can be used very effectively in an integrated manner to accurately assess and evaluate prospects.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Family Members Responding to a Visual Impairment.

    Science.gov (United States)

    Tuttle, Dean W.

    1986-01-01

    A literature review regarding family adjustment to a visually impaired family member considered the stages of denial, withdrawal, acceptance, depression, reaffirmation, coping, mobilization, and self-acceptance. (CB)

  18. Three Dimensional Pore Geometry change under different axial differential stress and Fluid Flow of Berea sandstone by LBM

    Science.gov (United States)

    Takahashi, M.; Takada, N.; Li, X.

    2013-12-01

    The Berea sandstone has a clear bedding plane and not clear cross lamina in cm size specimen, which is mainly caused by grain orientation and void space in microscopic scale. During the confined triaxial compression test, we measured permeability of Berea sandstone by constant head test for three mutually perpendicular directions under increasing differential axial stress. In general, the permeability of Berea sandstones decreased slightly with increasing the effective confining pressure and axial differential stress. Permeability anisotropy was also observed in the normal and two parallel directions to the bedding planes. We introduced the three-dimensional medial axis (3DMA) method of Lindquist et al. (2000) to quantify the flow-relevant geometric properties of the voids structure in Berea sandstone. Using these data, we also evaluated the number of connecting path between two faces, tortuosity and the shortest path distribution within an arbitrary region of Berea sandstone specimen. Geometrical information on the number of connecting path in an arbitrary volume CT data shows reasonable correlation between permeability anisotropy and mutually perpendicular directions normal and parallel to bedding planes. In addition, we introduced numerical simulation of fluid flow of pressurized Berea sandstone by LBM, to discuss the permeability change caused by pressurization on effective confining pressure and differential axial stress. We obtained the detail distributions of fluid pressure, fluid velocity and its vector distribution in rather narrow voids space more than 10 μm. It is confirmed that pressurization effect on permeability caused by the decrease of the connecting path and the shortest path between arbitrary faces, and then caused a complex condition of on fluid pressure and fluid velocity.

  19. 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...

  20. Analysis on metallogenic conditions and prospect of sandstone-type uranium deposits in Longchuan basin western Yunnan

    International Nuclear Information System (INIS)

    The author discusses geotectonics, geomorphologic landscape, and paleoclimate, uranium source, structural pattern and structural division of the Longchuan basin, lithologies and lithofaces of Upper Tertiary, hydrogeology and hydrogeochemistry, concentration of uranium and deep information, compares the above information with that of U-productive Longchuanjiang basin, and analyzes the metallogenic conditions of sandstone-type uranium deposits. It is considered that the tectonic-erosion depressions located on the hanging wall of water-blocking faults in the southeastern uplifted zone of the Longchuan basin, and containing abundant organic matter and carbonaceous matter are the prospective areas for sandstone-type uranium deposits in Longchuan basin