检索结果-南通市图书馆

Acta Geologica Sinica(English Edition) 2015年第4期89卷 1296-1306页

作者： HAN Denglin LI Man LI Zhong Anita TORABI Key Laboratory of Exploration Technologies for Oil and Gas Resources of the Ministry of Education Yangtze University College of Geosciences Yangtze University Institute of Geology and Geophysics Chinese Academy of Science Centre for Integrated Petroleum Research University of Bergen

The Cretaceous Bashijiqike Formation is the main gas-bearing strata in the northern structural deformation zone of Kuqa subbasin. The acidic dissolution of this formation arose at 5-4Ma, which corresponds to the late burial stage of the Bashijiqike Formation. Variability of interlayer due to rock composition is negligible. Differentiation of acidic dissolution in sandstones was controlled by difference in amount of exogenous acid fluid from underlying strata. For the absence of sedimentary and structural carrier system between the isolated sandstone reservoirs, most fluid-rock systems show relative sealing feature during later burial stage by sealing feature of formation pressure, geochemical characteristics of formation water and content of diagenetic products in sandstones. Variation of sealing effects for different fluid-rock systems is obvious. The pressure coefficient is inversely proportional to acidic dissolved porosity of sandstone reservoirs, indicating that the variation of sealing effects for fluid- rock system mainly controls the differentiation of acidic dissolution.

关键词： Cretaceous Kuqa subbasin diagenesis sealing feature dissolution

Dolomitization of the lower cretaceous carbonate reservoir in the Euphrates Graben,Syria

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2021年第5期18卷 1342-1356页

作者： Yousef Ibrahem V.P.Morozov V.Sudakov Institute of Geology and Petroleum Technologies Kazan Federal UniversityKazan420008Russian Federation

Results of this study are based on core materials description,thin sections,Cathodoluminescence(CL),and Scanning Electron Microscope(SEM)examinations.The Lower Cretaceous over the Euphrates Graben area was characterized by carbonate sedimentation in shallow marine environments.The low energy lagoonal to inner shelf sediments of the Judea Formation includes micritic mudstone to wackestone texture,dolomitic limestones and dolostones.Two types of dolomites recognized in the carbonates of the Judea Formation,the preserving microcrystalline dolomites which commonly founded in the partially dolomitized micritic limestones,and the destructive coarsely crystalline dolomites which commonly founded in the dolostones and dolomitic limestones.Petrographic examinations indicate that the preserving microcrystalline dolomites represent subtidal cycles developed in a shoal to open marine depositional environments,they probably formed under conditions of the shallow burial diagenesis.The destructive coarsely crystalline dolomites may develop in more basinward,open marine environments under conditions of the deep burial diagenesis that accompanied by rising in temperature,pressure,and burial depth.It is believed that evolution of the diagenetic history of the Judean Formation sediments occurred in two diagenetic stages;the shallow burial diagenesis,and the deep burial diagenesis.Compaction processes,early fracturing,micritization,early calcite,and the early phase of dolomitization were part of the multiple diagenetic alterations during the shallow burial diagenesis.The deep burial diagenesis was marked by dissolution,late stage of dolomitization and replacement,mechanical and chemical compaction,and the late calcite precipitation.It is believed that dolomitization of the Judea Formation carbonates in the Euphrates Graben has contributed to improving the reservoir properties by increasing the porosity and thus the permeability.

关键词： Dolomitization Carbonate diagenesis Burial history Euphrates graben Syria

Characteristics and Origin of Tight Oil Accumulations in the Upper Triassic Yanchang Formation of the Ordos Basin,North-Central China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第5期90卷 1821-1837页

作者： WU Songtao ZOU Caineng ZHU Rukai YAO Jingli TAO Shizhen YANG Zhi ZHAI Xiufen CUI Jingwei LIN Senhu Research Institute of Petroleum Exploration & Development PetroChina Beijing 100083 China State Key Laboratory of Enhanced Oil Recovery Beijing 100083 China CNPC Key Laboratory of Oil and Gas Reservoirs Beijing 100083 China Changqing Oilfield Company PetroChina Xi 'an 710067 Shaanxi China

The Upper Triassic oil accumulations in the Ordos Basin is the most successful tight oil play in China,with average porosity values of less than 10% and permeability values below 1.0 mD.This study investigated the geological characteristics and origin of the tight oil accumulations in the Chang 6 member of the Upper Triassic Yanchang Formation in the Shanbei area based on over 50,000 petrological,source-rock analysis,well logging and production data.The tight oil accumulation of the Chang 6 member is distributed continuously in the basin slope and the centre of the basin.The oilwater relationships are complex.Laumontite dissolution pores are the most important storage spaces,constituting 30%-60% of total porosity and showing a strong positive relationship with oil production.The pore-throat diameter is less than 1 μm,and the calculated critical height of the oil column is much larger than the tight sand thickness,suggesting that the buoyancy was probably of limited importance for oil migration.The pressure difference between the source rocks and sandstone reservoirs is inferred to have provided driving force for hydrocarbon migration.Two factors of source-reservoir configuration and laumontite dissolution contributed to the formation of the Chang 6 tight oil accumulations.Intense hydrocarbon generation and continuous sand bodies close to the hydrocarbon kitchen are the foundation for the large-scale oil distribution.Dissolution of feldspar-laumontite during the process of organic matter evolution generated abundant secondary pores and improved the reservoir quality.

关键词： tight oil diagenesis tight sand nanopores Yanchang Fm. Ordos Basin

Classification and Diagenetic Characteristics of the Cretaceous Sandstones in the Southern Bredasdorp Basin,Offshore South Africa

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2021年第5期95卷 1695-1713页

作者： Temitope Love BAIYEGUNHI Kuiwu LIU Oswald GWAVAVA Christopher BAIYEGUNHI Department of Geology University of Fort HarePrivate Bag X1314Alice 5700Eastern Cape ProvinceSouth Africa Department of Geology and Mining University of LimpopoPrivate Bag X1106Sovenga 0727Limpopo ProvinceSouth Africa

A systematic petrographic and geochemical studies of 92 representative sandstone samples from exploration wells E-AH1,E-AJ1,E-BA1,E-BB1 and E-D3 in the southern part of the Bredasdorp Basin was undertaken to classify the sandstones as well as unravel the main diagenetic processes and their time relations.Petrographic study shows that the sandstones are largely subarkosic arenite and arkosic litharenite,which have underwent series of diagenetic processes as a result burial,rifting and subsequent uplift.The main diagenetic processes that have affected the reservoir properties of the sandstones are cementation by authigenic clay,carbonate and silica,growth of authigenic glauconite,dissolution of minerals and load compaction.The major diagenetic processes reducing the porosity are calcite cementation in the subarkosic arenite,and compaction and quartz cementation in arkosic litharenite.On the other hand,the formation of secondary porosity due to the partial to complete dissolution of early calcite cement,feldspars and minor grain fracturing has improved the reservoir property of the sandstone to some extent.The clay minerals in the sandstones commonly acts as pore choking cement,which reduces porosity.In general,there is no particular diagenetic process that exclusively controls the type or form of porosity evolution in the sandstones.

关键词： diagenesis cementation reservoir properties sandstones Bredasdorp Basin

Reservoir characteristics,formation mechanisms and petroleum exploration potential of volcanic rocks in China

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2015年第1期12卷 54-66页

作者： Zhi-Guo Mao Ru-Kai Zhu Jing-Lan Luo Jing-Hong Wang Zhan-Hai Du Ling Su Shao-Min Zhang Research Institute of Petroleum Exploration & Development Petro China State Key Laboratory of Enhanced Oil Recovery Northwest University Xi’an 710069 State Key Laboratory of Continental Dynamics International Iraq FZE Petro China China University of Petroleum

Characterized by complex lithology and strong heterogeneity, volcanic reservoirs in China developed three reservoir space types： primary pores, secondary pores and fractures. The formation of reservoir space went through the cooling and solidification stage （including blast fragmentation, crystallization differentiation and solidification） and the epidiagenesis stage （including metasomatism, filling, weathering and leaching, formation fluid dissolution and tectonism）. Primary pores were formed at the solidification stage, which laid the foundation for the development and transformation of effective reservoirs. Secondary pores were formed at the epidiagenesis stage, with key factors as weathering and leaching, formation fluid dissolution and tectonism. In China, Mesozoic-Cenozoic volcanic rocks developed in the Songliao Basin and Bohai Bay Basin in the east and Late Paleozoic volcanic rocks developed in the Junggar Basin, Santanghu Basin and Ta- rim Basin in the west. There are primary volcanic reser- voirs and secondary volcanic reservoirs in these volcanic rocks, which have good accumulation conditions and great exploration potential.

关键词： Volcanic reservoirs diagenesis Formation mechanism Hydrocarbon exploration

Quantification and timing of porosity evolution in tight sand gas reservoirs:an example from the Middle Jurassic Shaximiao Formation,western Sichuan,China

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2015年第2期12卷 207-217页

作者： Zheng-Xiang Lü Su-Juan Ye Xiang Yang Rong Li Yuan-Hua Qing State Key Laboratory of Oil and Gas Reservoir Geology &Exploitation Chengdu University of Technology Exploration and Production Research Institute Sinopec Southwest Chengdu Institute of Geology and Mineral Resources PetroChina Tarim Oilfield Company

The diagenesis and porosity evolution of the Middle Jurassic Shaximiao sandstones were analyzed based on petrographic observations, X-ray diffractometry, scanning electron microscopy observations, carbon and oxygen stable isotope geochemistry, fluid inclusion mi- crothermometry, and thermal and burial history modeling results. The point count data show that secondary pores （av. 5.5 %） are more abundant than primary pores （av. 3.7 %） and are thus the dominant pore type in the Shaximiao sandstones. Analysis of porosity evolution indicates that alteration of sandstones mainly occurred during two paragenetic stages. Mechanical compaction and cementa- tion by early chlorite, calcite, and quartz typically decrease the depositional porosity （40.9 %） by an average of 37.2 %, leaving porosity of 3.7 % after stage I （〈85 ℃, 175-145 Ma）. The original intergranular porosity loss due to compaction is calculated to be 29.3 %, suggesting that mechanical compaction is the most significant diagenetic process in primary porosity destruction. Stage II can be further divided into two sub-stages （Stage IIa and Stage IIb）. Stage IIa （85-120 ℃, 145-125 Ma） is characterized by late dissolution, which enhanced porosity by 8.8 %, and the porosity increased from 3.7 % to 12.5 %. During stage IIb （〉120 ℃, 125-0 Ma）, the precipitation of late chlorite, calcite, quartz, and kaolinite destroyed 3.3 % porosity, leaving porosity of 9.2 % in the rock today.

关键词： diagenesis Porosity evolution -Tight gas sandstones Jurassic Western Sichuan

Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2021年第2期10卷 197-208页

作者： Xi-Yang Zhang Yue Li Guan Wang Hong-Qiang Yang Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyInnovation Academy of South China Sea Ecology and Environmental EngineeringChinese Academy of SciencesGuangzhou 510301Guangdong ProvinceChina State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of SciencesNanjing 210008Jiangsu ProvinceChina.

A comprehensive study on the accretion and diagenesis of the Permian–Triassic boundary microbialites is conducive to a better understanding of the ecological community after the end-Permian mass extinction. Here we studied the special microbialite sequences at the Tianba section of Leye isolated carbonate platform, South China Block. The microbialites are shown as small columnar stromatolites, stromatolitic thrombolites, spotted thrombolites,and domical digitate thrombolites in an ascending order. Thin section analyses, coupled with cathodoluminescence photos and oxygen isotopic data, reveal that all types of microbially-mediated laminae/clots are partly recrystallized.Layers of the Polybessurus-like fossils commonly occur in the recrystallized fabrics of stromatolitic laminae. However,the Polybessurus-like fossils are rare in quantity and generally fragmentary and structureless in stromatolitic clots and spotted clots. Such taphonomic features are likely interpreted as the early decomposition by heterotrophic bacteria in an oxygen-depleted microenvironment caused by rapid accumulations of organic matter in the calm water.More enrichments of ~(13)C in the laminae of stromatolite and in the clots of stromatolitic thrombolite and spotted thrombolite than in adjacent interstitial matrixes signify the photosynthesis-dominated isotopic fractionation during the growth of microbial communities. Rare calcimicrobial structures but many calcite crystal fans were found in the ~(13)C-depleted digitate clots. These phenomena indicate that seawater on the carbonate platform was ~(12)C-enriched and supersaturated, accelerating carbonate precipitations and decompositions of organic matter within the microbial community. Different preservations of the Polybessurus-like fossil revealed the complicated microbiallydominated sedimentation and post-depositional diagenesis in the abnormal seawater after the catastrophe.

关键词： Microbialite Calcimicrobe Carbon isotope diagenesis End-Permian mass extinction South China Block

Authigenic clay minerals and calcite dissolution influence reservoir quality in tight sandstones:Insights from the central Junggar Basin,NW China

在线全文

学校读者我要写书评

暂无评论

能源地球科学(英文)

能源地球科学(英文) 2020年第1期1卷 8-19页

作者： Dongdong Hong Jian Cao Tao Wu Sisi Dang Wenxuan Hu Suping Yao State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjingJiangsu210023China Research Institute of Petroleum Exploration and Exploitation PetroChina Xinjiang Oilfield CompanyKaramayXinjiang834000China Exploration and Production Division of Luliang PetroChina Xinjiang Oilfield CompanyKaramayXinjiang834000China

Authigenic clays and calcite cements are important in the development of reservoir tightness and the formation of hydrocarbon sweet spots.We investigated Jurassic low-permeability sandstone reservoirs in the central Junggar Basin,NW China,using petrography,mineralogy,porosity,and permeability assessment,and stable C and O isotope analysis to ascertain the influence of authigenic clays and calcites on reservoir quality.Here,we establish the properties and diagenetic processes of the reservoir sandstones,and construct a generalizable model of reservoir quality.The results show that the sandstones are mainly litharenite and feldspathic litharenite and can be classified into ductile-lithic-rich sandstones and ductile-lithic-poor sandstones according to rock composition.The ductile-lithic-rich sandstones are tight(mean porosity?7.31%;mean permeability?0.08 mD)as a result of intense compaction.In contrast,the ductile-lithic-poor sandstones can be classified into five types according to diagenetic process.The formation of favorable hydrocarbon reservoir properties is closely related to the presence of authigenic clays and dissolution of calcite.In particular,kaolinite fills intergranular pores,thereby blocking pore space and reducing reservoir quality.Chlorite coating resists compaction and limits the formation of quartz overgrowths,thereby preserving pore space and enhancing reservoir quality.Calcite controls reservoir quality through both precipitation and dissolution.Calcite precipitation results in reduced reservoir quality,whereby early calcites that were precipitated in formation water resist compaction and provide the basis for subsequent dissolution and late precipitation,whereas dissolution of calcite in mesodiagenesis improves reservoir quality.A generalized model is formulated by relating diagenetic facies types to depth and porosity,providing a reference for other similar reservoirs.Our data suggest that deeply buried tight sandstones can be exploration prospects under favorable conditions involving the pres

关键词： diagenesis Calcite Kaolinite Chlorite Tight sandstone reservoir Central Junggar Basin

Diagenetic Evolution and Formation Mechanisms of High-Quality Reservoirs under Multiple Diagenetic Environmental Constraints:An Example from the Paleogene Beach-Bar Sandstone Reservoirs in the Dongying Depression,Bohai Bay Basin

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2017年第1期91卷 232-248页

作者： WANG Jian CAO Yingchang SONG Guoqi LIU Huimin School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Sinopec Shengli Oil Field Company Dongying 257000ShandongChina Institute of Geology Sinopec Shengli Oil Field CompanyDongying 257015ShandongChina

The diagenetic environment, diagenetic responses, diagenetic transformation model and formation mechanisms of high-quality reservoirs（beach-bar sandstones of the Paleogene fourth member） in the Dongying depression were studied through the analysis of fluid inclusions, thin section and burial evolution history. The diagenetic fluids of the beach-bar sandstone reservoirs evolved from early high salinity and weak alkalinity to low salinity and strong acidity, late high salinity and strong alkalinity and late low salinity and acidity, which were accompanied by two stages of oil and gas filling. The fluids at the margins of the sandbodies were continuously highly saline and strongly alkaline. The western（eastern） reservoirs experienced early open（closed）, middle open, and late closed diagenetic environments during their burial history. The flow pattern was characterized by upwelling during the majority of the diagenesis（in the east, a non-circulating pattern transitioned into an upwelling current）. Due to the evolution of the diagenetic fluids, the diagenetic sequence of the beach-bar reservoirs was as follows： early weak carbonate cementation; feldspar and carbonate cement dissolution and authigenic quartz cementation; late carbonate and anhydrite cementation, authigenic feldspar cementation, and late quartz dissolution; and late carbonate cementation, feldspar dissolution, and authigenic quartz cementation. The diagenetic strength during these stages varied or was absent altogether in different parts of the reservoirs. Due to the closeness of the diagenetic environment and the flow pattern of the diagenetic fluids, the diagenetic products are variably distributed in the sandstones interbedded with mudstones and in the fault blocks. The evolution of multiple alternating alkaline and acidic diagenetic environments controlled the distribution patterns of the reservoir diagenesis and reservoir space, and the reservoir quality index, RQI, increased gradually from the margins to the centers of the sandstones. The closenes

关键词： diagenetic environment diagenesis diagenetic fluids beach-bar high quality reservoir Dongying depression

The Origin and Tectonic Setting of Precambrian Greywacke of Ribandar-Chimbel, Goa, India： Petrological and Geochemical Evidence

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第6期90卷 2036-2048页

作者： Glancia Q FERNANDES Sridhar D. IYER Mahender KOTHA Department of Earth Science Goa University Taleigao Plateau Goa 403206 India Department of Civil Engineering Don Bosco College of Engineering Fatorda Margao Goa 403602 India CSIR-National Institute of Oceanography Dona Paula Goa 403004 India

The Precambrian greywacke of Ribandar-Chimbel belonging to the Sanvordem Formation of the Goa Group, India, has been studied for petrography and analyzed for major trace elements. The greywacke is characterized by angular to sub-round grains of quartz, feldspar, biotite, chlorite and clay minerals. The abundance of clay in the matrix seems to have influenced the Al2O3 content and the K20/Al2O3 ratio. The variation diagrams indicate a decreasing trend of TiO2, Al2O3, Fe2O3 and MgO; whereas Na2O and CaO exhibit a scatter which could be a result of the variable presence of feldspar within the sediments. The immobile elements, vanadium （25 to 144 ppm）, nickel （up to 107 ppm） and chromium （up to 184 ppm）, reflect abundance of clay minerals. The greywacke shows strongly fractionated REE patterns with LaN/YbN = 8 to 26 and with higher total REE abundances （up to 245 ppm）. The low REE enrichment and depletion in heavier REE with prominent negative Eu anomaly （Eu/Eu^＊= 0.54 to 0.79） suggest a derivation of the greywacke from an old upper continental crust composed chiefly of felsic components. Petrological evidence and geochemical data suggest that the deposition of the greywacke largely took place in a deep to shallow basin that progressively chang- ed from that of a continental island arc to an active continental setting.

关键词： greywacke petrochemistry origin diagenesis active continental setting Goa Dharwar Craton