Previously,troughs in continental faulted depressions were usually considered as a zone of hydrocarbon generation and expulsion rather than a zone for hydrocarbon accumulation.If they were confirmed to be the source k...Previously,troughs in continental faulted depressions were usually considered as a zone of hydrocarbon generation and expulsion rather than a zone for hydrocarbon accumulation.If they were confirmed to be the source kitchen,the possibility that they could constitute potential plays would be overlooked in the subsequent exploration program.Based on the hydrocarbon exploration practice of the Jizhong Depression and the Erlian Basin in the past several years,this paper discusses a new understanding that reservoir distribution is controlled by multiple factors and lithological accumulations are more likely to form in trough areas.It further documents the three main factors controlling the formation of large lithological hydrocarbon accumulations in trough areas.The paper also discusses the new concept that structural and lithological accumulations not only co-exist but also complement each other.We propose that fan-delta fronts on inverted steep slopes in troughs,delta fronts and sublacustrine fans on gentle slopes,channel sands along toes of fault scarps are favorable locations for discovery of new oil accumulations.The application of this concept has led to the discovery of several hundreds of million tonnes of oil in place in trough areas in the Jizhong Depression and the Erlian Basin.展开更多
Based on the latest drilling, seismic and field outcrop data, the geological characteristics(e.g. strata, development and sedimentary evolution) of the southern segment of the Late Sinian–Early Cambrian Deyang–Anyue...Based on the latest drilling, seismic and field outcrop data, the geological characteristics(e.g. strata, development and sedimentary evolution) of the southern segment of the Late Sinian–Early Cambrian Deyang–Anyue rift trough in the Sichuan Basin are analyzed. First, the strata in the southern segment are complete. The first to second members of Dengying Formation(Deng 1 + Deng 2) are found with relatively stable thickness(400–550 m), and the third to fourth members(Deng 3+ Deng 4) show great thickness difference between the marginal trough and the inner trough, which is up to 250 m. The Cambrian Maidiping Formation and Qiongzhusi Formation in southern Sichuan Basin are relatively thin, with the thickness changing greatly and frequently. Second, the Deyang–Anyue rift trough extended southward during the Deng 4 period, affecting southern Sichuan Basin. Compared to the middle and northern segments of the rift trough, the southern segment is generally wide, gentle and shallow, with multiple steps, and alternating uplifts and sags, which are distributed in finger shape. Third, the Deng 1 + Deng 2 in southern Sichuan Basin records the dominance of carbonate platform and unobvious sedimentary differentiation, and the Deng 4 exhibits obvious sedimentary differentiation, namely, basin–slope–secondary slope–slope–secondary slope–platform margin–restricted platform, from the inner trough to the marginal trough. Fourth, the rift trough in southern Sichuan Basin has evolved in four stages: stabilization of Deng 1–Deng 2, initialization of Deng 3–Deng 4, filling of Maidiping–Qiongzhusi, and extinction of Canglangpu Formation.展开更多
Based on analysis of field survey, drilling and seismic data, the formation and evolution process of Deyang-Anyue erosion rift trough in Sichuan Basin was reconstructed, and exploration areas were divided and evaluate...Based on analysis of field survey, drilling and seismic data, the formation and evolution process of Deyang-Anyue erosion rift trough in Sichuan Basin was reconstructed, and exploration areas were divided and evaluated. The results show that:(1) Dengying Formation in and around Deyang-Anyue erosion rift trough varies widely in sedimentary characteristics. The Dengying Formation in the northern part of the erosion rift trough developed deep-water sediments, the Dengying Formation in the northern part of the basin varied gradually from basin to slope, platform margin, and restricted platform, and the Dengying Formation in the middle and southern parts of the trough developed carbonate platform facies.(2) Deyang-Anyue erosion rift trough is formed by extensional rift and karst erosion jointly, the north section of the erosion rift trough is mainly the product of tensile rift, while the middle and south sections are formed by erosion in multi-episodes of Tongwan period.(3) Based on the segmented origins of the erosion rift trough, Dengying Formation in and around it is divided into three exploration fields: lithologic mound and beach bodies at the northern platform margin of the basin, karst mound and beach bodies in the central platform, and karst residual mounds in the central southern trough of the basin, among them, the karst residual mounds in the central southern trough of the basin are a new frontier for natural gas exploration in the basin, and the lithologic mound and beach bodies at the northern platform margin are a new position for increasing the reserves of trillions of cubic meters of natural gas resources in the basin.展开更多
The expression of Wu’s hydrodynamic soliton in a sloping trough was derived wing the perturbation method of multiple scales.It showed that the soliton slowly moves toward the shallow end with uniform acceleration,whi...The expression of Wu’s hydrodynamic soliton in a sloping trough was derived wing the perturbation method of multiple scales.It showed that the soliton slowly moves toward the shallow end with uniform acceleration,which is consistent with Wu’s experiment.展开更多
Based on outcrop characteristics, combined with regional tectonic background, drilling and geophysical data, the sedimentary characteristics of the Middle Permian Maokou Formation in the northern Sichuan Basin was stu...Based on outcrop characteristics, combined with regional tectonic background, drilling and geophysical data, the sedimentary characteristics of the Middle Permian Maokou Formation in the northern Sichuan Basin was studied by means of macroscopic and microscopic observation, geochemical element test, total organic carbon content and vitrinite reflectance measurement. There is a set of deep-water sediments rich in organic matter in the Guangyuan-Wangcang area of northern Sichuan during the late depositional period of the Middle Permian Maokou Formation. The strata are distributed from northwest to southeast, with thickness of 10–30 m, mainly composed of siliceous rocks and siliceous mudstones, intercalated with gravity flow deposits. Siliceous rocks and siliceous mudstones are characterized by thin single layer, flat bedding and rich siliceous radiolarians, calthrop and brachiopod with small body and thin shell, belonging to the typical sedimentary characteristics of deep-water trough facies. The contents of Cu, Co, Mo, Ni and the ratio of Ni to Co in the geochemical tests all indicate that the siliceous rocks are products of deep-water reducing environment. The TOC value ranges from 3.21% to 8.19%, with an average of 5.53%, indicating that the siliceous rocks have good hydrocarbon generation ability. The south side of the trough is in platform margin facies with high energy, and the sediments are mainly thick massive micritic-calcsparite biogenic(clastic) limestone, which is conducive to the formation and evolution of the reservoir. During the late sedimentary period of the Maokou Formation, the northward subduction and extension of the oceanic crust at the northwestern margin of the Yangtze Plate provided the internal dynamic conditions for the formation of the "Guangyuan-Wangcang" trough. According to the location, sedimentary characteristics and formation dynamics of the trough, it is similar to the "Kaijiang-Liangping" trough during Late Permian proposed by previous researchers. It is believed that the "Kaijiang-Liangping" trough already had its embryonic form during the Late Middle Permian.展开更多
Based on the merged 3 D seismic data, well logging, formation testing, analysis and testing data, the structural evolution, sedimentary reservoirs, thermal evolution of source rocks were investigated of Paleogene Kong...Based on the merged 3 D seismic data, well logging, formation testing, analysis and testing data, the structural evolution, sedimentary reservoirs, thermal evolution of source rocks were investigated of Paleogene Kongdian Formation in the trough area of Cangdong sag, Bohai Bay Basin. A conventional-unconventional hydrocarbon accumulation pattern in the trough area of rifted basin was revealed. The reservoir forming elements in the trough area of Cangdong sag have a zonation feature in terms of reservoirs and source rocks. There are two types of reservoir forming models, primary trough and reformed trough. The formation and evolution of trough controlled the orderly distribution of conventional oil to unconventional oil in the trough. Particularly, structural reservoirs occur in the upper part of the trough, stratigraphic-lithologic reservoirs are likely to form in the delta front deposits at the outer ring of trough, the middle ring transitional belt is the favorable site for tight oil reservoirs, while the fine grain deposits zone in the inner ring is shale oil and gas exploration area. The study has pointed out the new domains and directions for searching reserves in the secondary exploration of mature oilfields.展开更多
文摘Previously,troughs in continental faulted depressions were usually considered as a zone of hydrocarbon generation and expulsion rather than a zone for hydrocarbon accumulation.If they were confirmed to be the source kitchen,the possibility that they could constitute potential plays would be overlooked in the subsequent exploration program.Based on the hydrocarbon exploration practice of the Jizhong Depression and the Erlian Basin in the past several years,this paper discusses a new understanding that reservoir distribution is controlled by multiple factors and lithological accumulations are more likely to form in trough areas.It further documents the three main factors controlling the formation of large lithological hydrocarbon accumulations in trough areas.The paper also discusses the new concept that structural and lithological accumulations not only co-exist but also complement each other.We propose that fan-delta fronts on inverted steep slopes in troughs,delta fronts and sublacustrine fans on gentle slopes,channel sands along toes of fault scarps are favorable locations for discovery of new oil accumulations.The application of this concept has led to the discovery of several hundreds of million tonnes of oil in place in trough areas in the Jizhong Depression and the Erlian Basin.
基金Supported by the PetroChina Science and Technology Project (2021DJ0605,2022KT0101)the CNPC Major Science and Technology Project (2021DJ0501)。
文摘Based on the latest drilling, seismic and field outcrop data, the geological characteristics(e.g. strata, development and sedimentary evolution) of the southern segment of the Late Sinian–Early Cambrian Deyang–Anyue rift trough in the Sichuan Basin are analyzed. First, the strata in the southern segment are complete. The first to second members of Dengying Formation(Deng 1 + Deng 2) are found with relatively stable thickness(400–550 m), and the third to fourth members(Deng 3+ Deng 4) show great thickness difference between the marginal trough and the inner trough, which is up to 250 m. The Cambrian Maidiping Formation and Qiongzhusi Formation in southern Sichuan Basin are relatively thin, with the thickness changing greatly and frequently. Second, the Deyang–Anyue rift trough extended southward during the Deng 4 period, affecting southern Sichuan Basin. Compared to the middle and northern segments of the rift trough, the southern segment is generally wide, gentle and shallow, with multiple steps, and alternating uplifts and sags, which are distributed in finger shape. Third, the Deng 1 + Deng 2 in southern Sichuan Basin records the dominance of carbonate platform and unobvious sedimentary differentiation, and the Deng 4 exhibits obvious sedimentary differentiation, namely, basin–slope–secondary slope–slope–secondary slope–platform margin–restricted platform, from the inner trough to the marginal trough. Fourth, the rift trough in southern Sichuan Basin has evolved in four stages: stabilization of Deng 1–Deng 2, initialization of Deng 3–Deng 4, filling of Maidiping–Qiongzhusi, and extinction of Canglangpu Formation.
基金Supported by the National Key Research and Development Program of China (2017YFC0603106)Project of Science and Technology Department of PetroChina Southwest Oil and Gas Field Company (20200301-01)。
文摘Based on analysis of field survey, drilling and seismic data, the formation and evolution process of Deyang-Anyue erosion rift trough in Sichuan Basin was reconstructed, and exploration areas were divided and evaluated. The results show that:(1) Dengying Formation in and around Deyang-Anyue erosion rift trough varies widely in sedimentary characteristics. The Dengying Formation in the northern part of the erosion rift trough developed deep-water sediments, the Dengying Formation in the northern part of the basin varied gradually from basin to slope, platform margin, and restricted platform, and the Dengying Formation in the middle and southern parts of the trough developed carbonate platform facies.(2) Deyang-Anyue erosion rift trough is formed by extensional rift and karst erosion jointly, the north section of the erosion rift trough is mainly the product of tensile rift, while the middle and south sections are formed by erosion in multi-episodes of Tongwan period.(3) Based on the segmented origins of the erosion rift trough, Dengying Formation in and around it is divided into three exploration fields: lithologic mound and beach bodies at the northern platform margin of the basin, karst mound and beach bodies in the central platform, and karst residual mounds in the central southern trough of the basin, among them, the karst residual mounds in the central southern trough of the basin are a new frontier for natural gas exploration in the basin, and the lithologic mound and beach bodies at the northern platform margin are a new position for increasing the reserves of trillions of cubic meters of natural gas resources in the basin.
基金Project supported by the National Science Foundation of China.
文摘The expression of Wu’s hydrodynamic soliton in a sloping trough was derived wing the perturbation method of multiple scales.It showed that the soliton slowly moves toward the shallow end with uniform acceleration,which is consistent with Wu’s experiment.
基金Supported by the China National Science and Technology Major Project(2016ZX05007004-001,2017ZX05001001-002)PetroChina Innovation Foundation(2018D-5007-0105)Scientific Research Starting Project of SWPU(2017QHZ005)。
文摘Based on outcrop characteristics, combined with regional tectonic background, drilling and geophysical data, the sedimentary characteristics of the Middle Permian Maokou Formation in the northern Sichuan Basin was studied by means of macroscopic and microscopic observation, geochemical element test, total organic carbon content and vitrinite reflectance measurement. There is a set of deep-water sediments rich in organic matter in the Guangyuan-Wangcang area of northern Sichuan during the late depositional period of the Middle Permian Maokou Formation. The strata are distributed from northwest to southeast, with thickness of 10–30 m, mainly composed of siliceous rocks and siliceous mudstones, intercalated with gravity flow deposits. Siliceous rocks and siliceous mudstones are characterized by thin single layer, flat bedding and rich siliceous radiolarians, calthrop and brachiopod with small body and thin shell, belonging to the typical sedimentary characteristics of deep-water trough facies. The contents of Cu, Co, Mo, Ni and the ratio of Ni to Co in the geochemical tests all indicate that the siliceous rocks are products of deep-water reducing environment. The TOC value ranges from 3.21% to 8.19%, with an average of 5.53%, indicating that the siliceous rocks have good hydrocarbon generation ability. The south side of the trough is in platform margin facies with high energy, and the sediments are mainly thick massive micritic-calcsparite biogenic(clastic) limestone, which is conducive to the formation and evolution of the reservoir. During the late sedimentary period of the Maokou Formation, the northward subduction and extension of the oceanic crust at the northwestern margin of the Yangtze Plate provided the internal dynamic conditions for the formation of the "Guangyuan-Wangcang" trough. According to the location, sedimentary characteristics and formation dynamics of the trough, it is similar to the "Kaijiang-Liangping" trough during Late Permian proposed by previous researchers. It is believed that the "Kaijiang-Liangping" trough already had its embryonic form during the Late Middle Permian.
基金Supported by the China National Science and Technology Major Project(2016ZX05006-005)PetroChina Science and Technology Major Project(2018E-11)
文摘Based on the merged 3 D seismic data, well logging, formation testing, analysis and testing data, the structural evolution, sedimentary reservoirs, thermal evolution of source rocks were investigated of Paleogene Kongdian Formation in the trough area of Cangdong sag, Bohai Bay Basin. A conventional-unconventional hydrocarbon accumulation pattern in the trough area of rifted basin was revealed. The reservoir forming elements in the trough area of Cangdong sag have a zonation feature in terms of reservoirs and source rocks. There are two types of reservoir forming models, primary trough and reformed trough. The formation and evolution of trough controlled the orderly distribution of conventional oil to unconventional oil in the trough. Particularly, structural reservoirs occur in the upper part of the trough, stratigraphic-lithologic reservoirs are likely to form in the delta front deposits at the outer ring of trough, the middle ring transitional belt is the favorable site for tight oil reservoirs, while the fine grain deposits zone in the inner ring is shale oil and gas exploration area. The study has pointed out the new domains and directions for searching reserves in the secondary exploration of mature oilfields.
