The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted...The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted comprehensive analyses employing methodologies encompassing source rocks,oil geochemistry,and fluid inclusions.The results show that the abundance of organic matter of Jurassic source rocks is high,and the type of organic matter is ofⅡ-Ⅲand in mature evolution stage.The main source rocks of oil and gas are Huangshanjie Formation and Jurassic coal-bearing source rocks.Ahe Formation developed two stages of hydrocarbon charging,and the period is later than the reservoir densification time.Yangxia Formation oil charged before the reservoir densified,and the late gas charged after the reservoir densified.Hydrocarbon generation intensity of Jurassic source rocks has reached the basic conditions for the formation of tight gas reservoirs.Controlled by the difference of source rocks distribution and accumulation process,tight sandstone oil and gas accumulation conditions are better in the depression direction than in the southeast margin area.This study is of practical importance for expanding the exploration field and selecting favorable areas in the eastern Yangxia sag.展开更多
As China in the decades ahead is to go through significant reorganization in the power sector and the petrochemical industry will see considerable growth,the transportation infrastructure for petroleum and gas should ...As China in the decades ahead is to go through significant reorganization in the power sector and the petrochemical industry will see considerable growth,the transportation infrastructure for petroleum and gas should have a new shape. Implementing the largest infrastructure projects and creating on this basis a modern transportation network will not only see a new reincarnation of traditional industrial centers, but also open wider opportunities for regional development.展开更多
By conducting organic geochemical analysis of the samples taken from the drilled wells in Baiyun Sag of Pearl River Mouth Basin,China,the development characteristics of hydrocarbon source rocks in the sag are clarifie...By conducting organic geochemical analysis of the samples taken from the drilled wells in Baiyun Sag of Pearl River Mouth Basin,China,the development characteristics of hydrocarbon source rocks in the sag are clarified.Reconstruct the current geothermal field of the sag and restore the tectonic-thermal evolution process to predict the type,scale,and distribution of resources in Baiyun Sag through thermal pressure simulation experiments and numerical simulation.The Baiyun Sag is characterized by the development of Paleogene shallow lacustrine source rocks,which are deposited in a slightly oxidizing environment.The source rocks are mainly composed of terrestrial higher plants,with algae making a certain contribution,and are oil and gas source rocks.Current geothermal field of the sag was reconstructed,in which the range of geothermal gradients is(3.5–5.2)℃/100 m,showing an overall increasing trend from northwest to southeast,with significant differences in geothermal gradients across different sub-sags.Baiyun Sag has undergone two distinct periods of extensional process,the Eocene and Miocene,since the Cenozoic era.These two periods of heating and warming events have been identified,accelerating the maturation and evolution of source rocks.The main body of ancient basal heat flow value reached its highest at 13.82 Ma.The basin modelling results show that the maturity of source rocks is significantly higher in Baiyun main sub-sag than that in other sub-sags.The Eocene Wenchang Formation is currently in the stage of high maturity to over maturity,while the Eocene Enping Formation has reached the stage of maturity to high maturity.The rock thermal simulation experiment shows that the shallow lacustrine mudstone of the Wenchang Formation has a good potential of generating gas from kerogen cracking with high gas yield and long period of gas window.Shallow lacustrine mudstone of the Enping Formation has a good ability to generate light oil,and has ability to generate kerogen cracking gas in the late stage.The gas yield of shallow lacustrine mudstone of the Enping Formation is less than that of shallow lacustrine mudstone of the Wenchang Formation and the delta coal-bearing mudstone of the Enping Formation.The numerical simulation results indicate that the source rocks of Baiyun main sub-sag generate hydrocarbons earlier and have significantly higher hydrocarbon generation intensity than other sub-sags,with an average of about 1200×10^(4)t/km^(2).Oil and gas resources were mainly distributed in Baiyun main sub-sag and the main source rocks are distributed in the 3^(rd)and 4^(th)members of Wenchang Formation.Four favorable zones are selected for the division and evaluation of migration and aggregation units:No.(1)Panyu 30 nose-shaped structural belt,No.(3)Liuhua 29 nose-shaped uplift belt and Liwan 3 nose-shaped uplift belt,No.(2)gentle slope belt of Baiyun east sag,and No.(8)Baiyun 1 low-uplift.展开更多
This study predicts favorable oil and gas source-rock formation conditions in the Aryskum Depression of the South Turgay Basin,Kazakhstan.This study assesses the thermal maturity and characteristics of organic matter ...This study predicts favorable oil and gas source-rock formation conditions in the Aryskum Depression of the South Turgay Basin,Kazakhstan.This study assesses the thermal maturity and characteristics of organic matter by determining its environmental conditions using data from geochemical analysis of core(pyrolysis)and oil(biomarkers and carbon isotopic compositions)samples.According to the geochemical parameters obtained by pyrolysis,the oil generation potential of the original rocks of most studied samples varies from poor to rich.The facies–genetic organic matter is predominantly humic and less frequently humus–sapropel,indicating organic matter accumulation in the studied samples were under moderately reducing conditions(kerogenⅢand Ⅱ types)and coastal–marine environments(kerogen typeⅠ).The carbon isotopic compositions of oils derived from the Jurassic deposits of the Aryskum Depression also indicate the sapropelic and mixed humic–sapropelic type of organic matter(kerogenⅡandⅠ).Biomarker analysis of oils indicates original organic matter formation in an anoxic environment.展开更多
The Songpan-Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, gradually developed into a passive marginal basin on a passive continent margin in Early P...The Songpan-Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, gradually developed into a passive marginal basin on a passive continent margin in Early Paleozoic, and later, with the Qinling-Qilian oceanic crust subduction and ocean closure, the Caledonides were formed and the foreland basin was superimposed upon. Being influenced by the Paleo-Tethyan extension, intra-continental rifting-margin basins were formed in Late Paleozoic. Following the formation of peripheral orogenic belt, the Upper Triassic again superimposed the foreland basin. The Mesozoic and Cenozoic overprinted the faulted basin, forming the Qinghai-Tibet Plateau domes. Hydrocarbon source rock in the Early Paleozoic passive basin, the Upper Paleozoic platform carbonates and the Triassic mudstones comprise the main source-reservoircap combination. Each layer of this area is at the advanced stage of diagenetic evolution, being entered the middle and late diagenetic stages, and anadiagenetic stage. Besides the highly matured Triassic and Permian in Zoige and Hongyuan, almost all the area is at the early stage of over maturatation, generating much methane. This area has the potential for oil and gas.展开更多
Comprehensive analyses were made based on seismic prospecting data, electrical prospecting data and basin simulation data as well as regional geological data and thorough discussions were conducted about the complicat...Comprehensive analyses were made based on seismic prospecting data, electrical prospecting data and basin simulation data as well as regional geological data and thorough discussions were conducted about the complicated structures, features and evolution of Hefei Basin in Early Cretaceous in this study, and it was derived that that Hefei Basin was a composite basin formed during the transformation of the stress field from compressive toward tensile in Early Cretaceous. In other words, this basin was a foreland basin of gliding-thrust type, which is mainly controlled by the Dabie orogenic belt in the south side in the early to middle period of Early Cretaceous, while being a strike-slip basin of pull-apart type, which is mainly controlled by the activity of Tanlu fracture in the east side in the middle to late period of Early Cretaceous. Moreover, the potential Lower Cretaceous oil and gas system in the pull-apart basin and the vista for its prospecting were explored in this study. Tectonism of the Tanlu fracture was further discussed based on the results of characterization of the basin, and it was pointed out that this is beneficial and instructive to the oil and gas prospecting in Hefei Basin展开更多
The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,...The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,the formation time of high-quality reservoirs,and the preservation mechanism of reservoirs have always limited exploration decision-making.This research systematically elaborates on the genesis and reservoir-forming mechanisms of Sinian-Cambrian dolomite,discussing the ancient marine environment where microorganisms and dolomite develop,which controls the formation of large-scale Precambrian-Cambrian dolomite.The periodic changes inMg isotopes and sedimentary cycles show that the thick-layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale.Lattice defects and dolomite embryos can promote dolomitization.By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights,the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed,and the mechanism of dolomitization was also demonstrated.The properties of calcite and dolomite(104)/(110)grain boundaries and their dissolution mechanism in carbonate solution were revealed,showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs.The in situ laser U-Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks.This research also proposed that dolomitization occurred during the quasi-contemporaneous or shallow-burial periods within 50Ma after deposition and pores formed during the quasi-contemporaneous to the early diagenetic periods.And it was clear that the quasi-contemporaneous dolomitization was the key period for reservoir formation.The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large-scale dolomite reservoirs.It clarifies the targets for oil and gas exploration at depths over 10000 m.The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10000-m deep oil exploration.展开更多
Shale oil and gas plays in continental rift basins are complicated and have not been reported elsewhere.In the Luojia area of the Jiyang Depression,an evaluation workflow for shale oil and gas in this continental rift...Shale oil and gas plays in continental rift basins are complicated and have not been reported elsewhere.In the Luojia area of the Jiyang Depression,an evaluation workflow for shale oil and gas in this continental rift basin is proposed.Based on analysis of oil-and gas-related geological conditions,a favorable area of shale oil and gas can be identified,and a high-frequency sequence stratigraphic framework of the target area can be established,therefore,the spatiotemporal distribution of shale has been elucidated in the Luojia area.According to the rock texture,structure,composition and color,petrographic classification criteria for shale are determined,and well log data are used to demarcate,track and predict high-quality lithofacies.Based on geochemical analyses and physical simulations of hydrocarbon generation,abundance,types and maturity of organic matter are analyzed,furthermore,geochemical parameters criteria of hydrocarbon generation and the characteristics of oil and gas occurrence in shales can be determined.Storage space types,assemblages and evolution characteristics of shale reservoirs are studied through core observation,thin-section analysis,electron microscopy examination and fluorescence spectrometry.Combined with analysis of reservoir physical properties,the reservoir performance is evaluated.A saturation model is established based on core analysis,well-log interpretation and well-test production data.The model is further used for evaluation of the movable hydrocarbon contents and integrated assessment of the oil potential.Finally,the shale oil and gas production capacity and exploration prospects in the Luojia area are forecasted based on the analyses of factors controlling production capacity and the rock fracability.Through an integrated analysis of multi-factors(including the lithofacies,source rocks,reservoir properties,oil saturation,and production capacity),the shales in the Luojia area can be divided into three categories,i.e.,Class I(high porosity-high resistivity),Class II(medium porosity-medium resistivity),and Class III(low porosity-medium resistivity).展开更多
基金supported by Joint Fund Project of National Natural Science Foundation(No.U22B6002)CNPC Scientific Research and Technology Development Project(No.2023ZZ14YJ02).
文摘The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted comprehensive analyses employing methodologies encompassing source rocks,oil geochemistry,and fluid inclusions.The results show that the abundance of organic matter of Jurassic source rocks is high,and the type of organic matter is ofⅡ-Ⅲand in mature evolution stage.The main source rocks of oil and gas are Huangshanjie Formation and Jurassic coal-bearing source rocks.Ahe Formation developed two stages of hydrocarbon charging,and the period is later than the reservoir densification time.Yangxia Formation oil charged before the reservoir densified,and the late gas charged after the reservoir densified.Hydrocarbon generation intensity of Jurassic source rocks has reached the basic conditions for the formation of tight gas reservoirs.Controlled by the difference of source rocks distribution and accumulation process,tight sandstone oil and gas accumulation conditions are better in the depression direction than in the southeast margin area.This study is of practical importance for expanding the exploration field and selecting favorable areas in the eastern Yangxia sag.
文摘As China in the decades ahead is to go through significant reorganization in the power sector and the petrochemical industry will see considerable growth,the transportation infrastructure for petroleum and gas should have a new shape. Implementing the largest infrastructure projects and creating on this basis a modern transportation network will not only see a new reincarnation of traditional industrial centers, but also open wider opportunities for regional development.
基金Supported by the National Oil and Gas Resource Evaluation Project for the 14th Five Year Plan of the Ministry of Natural Resources(QGYQZYPJ2022-3)China National Offshore Oil Corporation"14th Five Year Plan"Major Science and Technology Project(KJGG2022-0103-03)。
文摘By conducting organic geochemical analysis of the samples taken from the drilled wells in Baiyun Sag of Pearl River Mouth Basin,China,the development characteristics of hydrocarbon source rocks in the sag are clarified.Reconstruct the current geothermal field of the sag and restore the tectonic-thermal evolution process to predict the type,scale,and distribution of resources in Baiyun Sag through thermal pressure simulation experiments and numerical simulation.The Baiyun Sag is characterized by the development of Paleogene shallow lacustrine source rocks,which are deposited in a slightly oxidizing environment.The source rocks are mainly composed of terrestrial higher plants,with algae making a certain contribution,and are oil and gas source rocks.Current geothermal field of the sag was reconstructed,in which the range of geothermal gradients is(3.5–5.2)℃/100 m,showing an overall increasing trend from northwest to southeast,with significant differences in geothermal gradients across different sub-sags.Baiyun Sag has undergone two distinct periods of extensional process,the Eocene and Miocene,since the Cenozoic era.These two periods of heating and warming events have been identified,accelerating the maturation and evolution of source rocks.The main body of ancient basal heat flow value reached its highest at 13.82 Ma.The basin modelling results show that the maturity of source rocks is significantly higher in Baiyun main sub-sag than that in other sub-sags.The Eocene Wenchang Formation is currently in the stage of high maturity to over maturity,while the Eocene Enping Formation has reached the stage of maturity to high maturity.The rock thermal simulation experiment shows that the shallow lacustrine mudstone of the Wenchang Formation has a good potential of generating gas from kerogen cracking with high gas yield and long period of gas window.Shallow lacustrine mudstone of the Enping Formation has a good ability to generate light oil,and has ability to generate kerogen cracking gas in the late stage.The gas yield of shallow lacustrine mudstone of the Enping Formation is less than that of shallow lacustrine mudstone of the Wenchang Formation and the delta coal-bearing mudstone of the Enping Formation.The numerical simulation results indicate that the source rocks of Baiyun main sub-sag generate hydrocarbons earlier and have significantly higher hydrocarbon generation intensity than other sub-sags,with an average of about 1200×10^(4)t/km^(2).Oil and gas resources were mainly distributed in Baiyun main sub-sag and the main source rocks are distributed in the 3^(rd)and 4^(th)members of Wenchang Formation.Four favorable zones are selected for the division and evaluation of migration and aggregation units:No.(1)Panyu 30 nose-shaped structural belt,No.(3)Liuhua 29 nose-shaped uplift belt and Liwan 3 nose-shaped uplift belt,No.(2)gentle slope belt of Baiyun east sag,and No.(8)Baiyun 1 low-uplift.
基金Funding from the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan under Grant Agreement No.AP13268843.
文摘This study predicts favorable oil and gas source-rock formation conditions in the Aryskum Depression of the South Turgay Basin,Kazakhstan.This study assesses the thermal maturity and characteristics of organic matter by determining its environmental conditions using data from geochemical analysis of core(pyrolysis)and oil(biomarkers and carbon isotopic compositions)samples.According to the geochemical parameters obtained by pyrolysis,the oil generation potential of the original rocks of most studied samples varies from poor to rich.The facies–genetic organic matter is predominantly humic and less frequently humus–sapropel,indicating organic matter accumulation in the studied samples were under moderately reducing conditions(kerogenⅢand Ⅱ types)and coastal–marine environments(kerogen typeⅠ).The carbon isotopic compositions of oils derived from the Jurassic deposits of the Aryskum Depression also indicate the sapropelic and mixed humic–sapropelic type of organic matter(kerogenⅡandⅠ).Biomarker analysis of oils indicates original organic matter formation in an anoxic environment.
文摘The Songpan-Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, gradually developed into a passive marginal basin on a passive continent margin in Early Paleozoic, and later, with the Qinling-Qilian oceanic crust subduction and ocean closure, the Caledonides were formed and the foreland basin was superimposed upon. Being influenced by the Paleo-Tethyan extension, intra-continental rifting-margin basins were formed in Late Paleozoic. Following the formation of peripheral orogenic belt, the Upper Triassic again superimposed the foreland basin. The Mesozoic and Cenozoic overprinted the faulted basin, forming the Qinghai-Tibet Plateau domes. Hydrocarbon source rock in the Early Paleozoic passive basin, the Upper Paleozoic platform carbonates and the Triassic mudstones comprise the main source-reservoircap combination. Each layer of this area is at the advanced stage of diagenetic evolution, being entered the middle and late diagenetic stages, and anadiagenetic stage. Besides the highly matured Triassic and Permian in Zoige and Hongyuan, almost all the area is at the early stage of over maturatation, generating much methane. This area has the potential for oil and gas.
文摘Comprehensive analyses were made based on seismic prospecting data, electrical prospecting data and basin simulation data as well as regional geological data and thorough discussions were conducted about the complicated structures, features and evolution of Hefei Basin in Early Cretaceous in this study, and it was derived that that Hefei Basin was a composite basin formed during the transformation of the stress field from compressive toward tensile in Early Cretaceous. In other words, this basin was a foreland basin of gliding-thrust type, which is mainly controlled by the Dabie orogenic belt in the south side in the early to middle period of Early Cretaceous, while being a strike-slip basin of pull-apart type, which is mainly controlled by the activity of Tanlu fracture in the east side in the middle to late period of Early Cretaceous. Moreover, the potential Lower Cretaceous oil and gas system in the pull-apart basin and the vista for its prospecting were explored in this study. Tectonism of the Tanlu fracture was further discussed based on the results of characterization of the basin, and it was pointed out that this is beneficial and instructive to the oil and gas prospecting in Hefei Basin
基金National Natural Science Foundation of China,Grant/Award Number:42230812。
文摘The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,the formation time of high-quality reservoirs,and the preservation mechanism of reservoirs have always limited exploration decision-making.This research systematically elaborates on the genesis and reservoir-forming mechanisms of Sinian-Cambrian dolomite,discussing the ancient marine environment where microorganisms and dolomite develop,which controls the formation of large-scale Precambrian-Cambrian dolomite.The periodic changes inMg isotopes and sedimentary cycles show that the thick-layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale.Lattice defects and dolomite embryos can promote dolomitization.By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights,the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed,and the mechanism of dolomitization was also demonstrated.The properties of calcite and dolomite(104)/(110)grain boundaries and their dissolution mechanism in carbonate solution were revealed,showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs.The in situ laser U-Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks.This research also proposed that dolomitization occurred during the quasi-contemporaneous or shallow-burial periods within 50Ma after deposition and pores formed during the quasi-contemporaneous to the early diagenetic periods.And it was clear that the quasi-contemporaneous dolomitization was the key period for reservoir formation.The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large-scale dolomite reservoirs.It clarifies the targets for oil and gas exploration at depths over 10000 m.The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10000-m deep oil exploration.
基金This work was funded by National Science and Technology Major Project of China(Grant No.2011ZX05006-003).
文摘Shale oil and gas plays in continental rift basins are complicated and have not been reported elsewhere.In the Luojia area of the Jiyang Depression,an evaluation workflow for shale oil and gas in this continental rift basin is proposed.Based on analysis of oil-and gas-related geological conditions,a favorable area of shale oil and gas can be identified,and a high-frequency sequence stratigraphic framework of the target area can be established,therefore,the spatiotemporal distribution of shale has been elucidated in the Luojia area.According to the rock texture,structure,composition and color,petrographic classification criteria for shale are determined,and well log data are used to demarcate,track and predict high-quality lithofacies.Based on geochemical analyses and physical simulations of hydrocarbon generation,abundance,types and maturity of organic matter are analyzed,furthermore,geochemical parameters criteria of hydrocarbon generation and the characteristics of oil and gas occurrence in shales can be determined.Storage space types,assemblages and evolution characteristics of shale reservoirs are studied through core observation,thin-section analysis,electron microscopy examination and fluorescence spectrometry.Combined with analysis of reservoir physical properties,the reservoir performance is evaluated.A saturation model is established based on core analysis,well-log interpretation and well-test production data.The model is further used for evaluation of the movable hydrocarbon contents and integrated assessment of the oil potential.Finally,the shale oil and gas production capacity and exploration prospects in the Luojia area are forecasted based on the analyses of factors controlling production capacity and the rock fracability.Through an integrated analysis of multi-factors(including the lithofacies,source rocks,reservoir properties,oil saturation,and production capacity),the shales in the Luojia area can be divided into three categories,i.e.,Class I(high porosity-high resistivity),Class II(medium porosity-medium resistivity),and Class III(low porosity-medium resistivity).
