Based on the oil and gas exploration in the Sichuan Basin,combined with data such as seismic,logging and geochemistry,the basic geological conditions,hydrocarbon types,hydrocarbon distribution characteristics,source-r...Based on the oil and gas exploration in the Sichuan Basin,combined with data such as seismic,logging and geochemistry,the basic geological conditions,hydrocarbon types,hydrocarbon distribution characteristics,source-reservoir relationship and accumulation model of the Upper Triassic–Jurassic continental whole petroleum system in the basin are systematically analyzed.The continental whole petroleum system in the Sichuan Basin develops multiple sets of gas-bearing strata,forming a whole petroleum system centered on the Triassic Xujiahe Formation source rocks.The thick and high-quality source rocks in the Upper Triassic Xujiahe Formation provide sufficient gas source basis for the continental whole petroleum system in the basin.The development of conventional-unconventional reservoirs provides favorable space for hydrocarbon accumulation.The coupling of faults and sandbodies provides a high-quality transport system for gas migration.Source rocks and reservoirs are overlapped vertically,and there are obvious differences in sedimentary environment,reservoir lithology and physical properties,which lead to the orderly development of inner-source shale gas,near-source tight gas,and far-source tight–conventional gas in the Upper Triassic–Jurassic,from bottom to top.The orderly change of geological conditions such as burial depth,reservoir physical properties,formation pressure and hydrocarbon generation intensity in zones controlled the formation of the whole petroleum system consisting of structural gas reservoir in thrust zone,shale gas-tight gas reservoir in depression zone,tight gas reservoir in slope zone,and tight gas–conventional gas reservoir in uplift zone on the plane.Based on the theory and concept of the whole petroleum system,the continental shale gas and tight gas resources in the Sichuan Basin have great potential,especially in the central and western parts with abundant unconventional resources.展开更多
Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late ...Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus(Late Triassic) and Liujianpus(Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger(Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation.展开更多
基金Supported by the Scientific and Technological Project of the Southwest Oil and Gas Field Company of PetroChina(20230301-23)。
文摘Based on the oil and gas exploration in the Sichuan Basin,combined with data such as seismic,logging and geochemistry,the basic geological conditions,hydrocarbon types,hydrocarbon distribution characteristics,source-reservoir relationship and accumulation model of the Upper Triassic–Jurassic continental whole petroleum system in the basin are systematically analyzed.The continental whole petroleum system in the Sichuan Basin develops multiple sets of gas-bearing strata,forming a whole petroleum system centered on the Triassic Xujiahe Formation source rocks.The thick and high-quality source rocks in the Upper Triassic Xujiahe Formation provide sufficient gas source basis for the continental whole petroleum system in the basin.The development of conventional-unconventional reservoirs provides favorable space for hydrocarbon accumulation.The coupling of faults and sandbodies provides a high-quality transport system for gas migration.Source rocks and reservoirs are overlapped vertically,and there are obvious differences in sedimentary environment,reservoir lithology and physical properties,which lead to the orderly development of inner-source shale gas,near-source tight gas,and far-source tight–conventional gas in the Upper Triassic–Jurassic,from bottom to top.The orderly change of geological conditions such as burial depth,reservoir physical properties,formation pressure and hydrocarbon generation intensity in zones controlled the formation of the whole petroleum system consisting of structural gas reservoir in thrust zone,shale gas-tight gas reservoir in depression zone,tight gas reservoir in slope zone,and tight gas–conventional gas reservoir in uplift zone on the plane.Based on the theory and concept of the whole petroleum system,the continental shale gas and tight gas resources in the Sichuan Basin have great potential,especially in the central and western parts with abundant unconventional resources.
基金supported by the National Natural Science Foundation of China (Grant No.41772008)the State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology, CAS)(Grant No.173127)and the comprehensive geological and mineral survey in Wumeng mountainous area conducted by China Geological Survey (Grant No.121201010000150002)
文摘Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus(Late Triassic) and Liujianpus(Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger(Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation.
