By the end of 2019,more than 220 gas fields had been discovered in the South China Sea.In order to accurately determine the geological characteristics of the large-and medium-sized gas fields in the South China Sea,th...By the end of 2019,more than 220 gas fields had been discovered in the South China Sea.In order to accurately determine the geological characteristics of the large-and medium-sized gas fields in the South China Sea,this study conducted a comprehensive examination of the gas fields.Based on the abundant available geologic and geochemical data,the distribution and key controlling factors of the hydrocarbon accumulation in the South China Sea were analyzed.The geological and geochemical features of the gas fields were as follows:(1)the gas fields were distributed similar to beads in the shape of a"C"along the northern,western,and southern continental margins;(2)the natural gas in the region was determined to be composed of higher amounts of alkane gas and less CO2;(3)the majority of the alkane gas was observed to be coal-type gas;(4)the gas reservoir types included structural reservoirs,lithologic reservoirs,and stratigraphic reservoirs,respectively;(5)the reservoir ages were mainly Oligocene,Miocene,and Pliocene,while the lithology was mainly organic reef,with some sandstone deposits;and(6)the main hydrocarbon accumulation period for the region was determined to be the late Pliocene-Quaternary Period.In addition,the main controlling factors of the gas reservoirs were confirmed to have been the development of coal measures,sufficient thermal evolution,and favorable migration and accumulation conditions.展开更多
Based on regional geology,2D seismic and ocean drilling data,the formation of the Eratosthenes Seamount(ESM)and its surrounding isolated platforms,types of organic reefs and hydrocarbon accumulation conditions in the ...Based on regional geology,2D seismic and ocean drilling data,the formation of the Eratosthenes Seamount(ESM)and its surrounding isolated platforms,types of organic reefs and hydrocarbon accumulation conditions in the eastern Mediterranean were analyzed through fine tectonic interpretation and seismic facies study,and the future exploration targets were pointed out.The formation and evolution of the ESM and its peripheral isolated platforms are highly related to the open and close of the Neotethyan ocean.The precursors of the ESM and its peripheral isolated platforms are both horst-type fault blocks formed in the Middle Triassic-Early Jurassic intracontinental rift stage.The ESM and its peripheral isolated platforms underwent continued and inherited carbonate build-ups during the Middle Jurassic intercontinental rift stage,the Late Jurassic-Late Cretaceous Turonian passive drift stage,and Late Cretaceous Senonian-Miocene subduction stage,as well as medium-slight inversion transformation beginning in the Late Miocene Messinian caused by the closure of the Neotethyan ocean.Three types of isolated platforms formed controlled by variant paleo-tectonic settings:the first type is composed of a single patch-like reef controlled by a small-scale and narrow horst-type fault block,the second type consists of a single atoll controlled by a middle-scale and wide horst-type fault block,and the third type is comprised of multiple reef-beach complexes controlled by a large-scale and broad paleo-high.The first two types universally developed in the highs of the alternate sag-uplift structural zones on the south and west of Eratosthenes,and the third type only developed in the ESM.As a result of fluctuation of sea level,two sequences of reef build-ups,i.e.the Middle Jurassic Bajocian-Upper Cretaceous Turonian and the Miocene,developed in the ESM as well as the highs in the alternate sag-uplift structural zones on the south and west of Eratosthenes.Drillings have confirmed that the first two types of isolated platforms with a single patch-like reef and a single circle-like reef have good conditions for natural gas accumulations.The isolated platform of reef-beach complexes in the ESM also has accumulation potentials of natural gas and is worth prospecting.展开更多
基金The National Petroleum Major Projects under contract Nos 2016ZX05026,2011ZX05025 and 2008ZX05025the National Natural Science Foundation Major Research Program of China under contract No.91528303+3 种基金the National Program on Key Basic Research Project of China(973 Program)under contract No.2009CB219400the Key Laboratory Project of Gansu Province under contract No.1309RTSA041the National Natural Science Foundation of China under contract No.41872172the SDUST Research Found under contract No.2018TDJH101
文摘By the end of 2019,more than 220 gas fields had been discovered in the South China Sea.In order to accurately determine the geological characteristics of the large-and medium-sized gas fields in the South China Sea,this study conducted a comprehensive examination of the gas fields.Based on the abundant available geologic and geochemical data,the distribution and key controlling factors of the hydrocarbon accumulation in the South China Sea were analyzed.The geological and geochemical features of the gas fields were as follows:(1)the gas fields were distributed similar to beads in the shape of a"C"along the northern,western,and southern continental margins;(2)the natural gas in the region was determined to be composed of higher amounts of alkane gas and less CO2;(3)the majority of the alkane gas was observed to be coal-type gas;(4)the gas reservoir types included structural reservoirs,lithologic reservoirs,and stratigraphic reservoirs,respectively;(5)the reservoir ages were mainly Oligocene,Miocene,and Pliocene,while the lithology was mainly organic reef,with some sandstone deposits;and(6)the main hydrocarbon accumulation period for the region was determined to be the late Pliocene-Quaternary Period.In addition,the main controlling factors of the gas reservoirs were confirmed to have been the development of coal measures,sufficient thermal evolution,and favorable migration and accumulation conditions.
基金Supported by the China National Science and Technology Major Project(2016ZX05029001)the CNPC Science and Technology Project(2019D-4310)。
文摘Based on regional geology,2D seismic and ocean drilling data,the formation of the Eratosthenes Seamount(ESM)and its surrounding isolated platforms,types of organic reefs and hydrocarbon accumulation conditions in the eastern Mediterranean were analyzed through fine tectonic interpretation and seismic facies study,and the future exploration targets were pointed out.The formation and evolution of the ESM and its peripheral isolated platforms are highly related to the open and close of the Neotethyan ocean.The precursors of the ESM and its peripheral isolated platforms are both horst-type fault blocks formed in the Middle Triassic-Early Jurassic intracontinental rift stage.The ESM and its peripheral isolated platforms underwent continued and inherited carbonate build-ups during the Middle Jurassic intercontinental rift stage,the Late Jurassic-Late Cretaceous Turonian passive drift stage,and Late Cretaceous Senonian-Miocene subduction stage,as well as medium-slight inversion transformation beginning in the Late Miocene Messinian caused by the closure of the Neotethyan ocean.Three types of isolated platforms formed controlled by variant paleo-tectonic settings:the first type is composed of a single patch-like reef controlled by a small-scale and narrow horst-type fault block,the second type consists of a single atoll controlled by a middle-scale and wide horst-type fault block,and the third type is comprised of multiple reef-beach complexes controlled by a large-scale and broad paleo-high.The first two types universally developed in the highs of the alternate sag-uplift structural zones on the south and west of Eratosthenes,and the third type only developed in the ESM.As a result of fluctuation of sea level,two sequences of reef build-ups,i.e.the Middle Jurassic Bajocian-Upper Cretaceous Turonian and the Miocene,developed in the ESM as well as the highs in the alternate sag-uplift structural zones on the south and west of Eratosthenes.Drillings have confirmed that the first two types of isolated platforms with a single patch-like reef and a single circle-like reef have good conditions for natural gas accumulations.The isolated platform of reef-beach complexes in the ESM also has accumulation potentials of natural gas and is worth prospecting.
