For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system...For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system”based on the principles of systems theory.Integrating over 60 years of exploration achievements in the four major basins,the paper studies the basic geological conditions,hydrocarbon accumulation models and distribution characteristics of the system.With the core principle of“source-heat controlling natural gas and play-stratigraphy controlling accumulation”,it analyzes the distribution law of natural gas reservoirs covering“intra-sag,sag margin,extra-sag”and multi-stratigraphic sequences.The study shows that under the joint control of source and heat,the northern continental margin of the South China Sea can be divided into two major gas areas:the southern area dominated by coal-type gas and the northern area dominated by oil-type gas,with the former as the main body.Based on the distribution location of hydrocarbon kitchen,the total gas plays are classified into three types:intra-sag,sag margin and extra-sag.In the oil-type gas area of the northern coastal zone,the proportion of intra-sag natural gas is relatively high;in the coal-type gas area of the southern offshore zone,the proportions of intra-sag and sag margin natural gas are relatively large;while the scale of gas accumulation in the extra-sag plays is relatively small.Finally,it is clearly pointed out that the southern offshore zone is the main direction for the next natural gas exploration in the northern South China Sea.Specifically,in the offshore zone,the intra-sag play and middle-deep layers of the sag margin play in the Yingzhong sag should be focused for the Yinggehai Basin;the intra-sag play and sag margin play in the central depression are targets for the Qiongdongnan Basin;the middle-deep layers of the intra-sag play are targets for the Baiyun sag of the Pearl River Mouth Basin.Furthermore,in the northern depression zone of the Pearl River Mouth Basin within the coastal zone,the main exploration directions include the middle-deep layers of the intra-sag play in the Huizhou sag and the middle-deep layers of the intra-sag play in the Enping sag;in the Beibu Gulf Basin,the main directions are the middle-deep layers of the intra-sag play in the Weixinan sag and the middle-deep layers of the intra-sag play in the Haizhong sag.展开更多
Deepwater oil and gas exploration has become a global hotspot in recent years and the study of the deep waters of marginal seas is an important frontier research area.The South China Sea(SCS)is a typical marginal sea ...Deepwater oil and gas exploration has become a global hotspot in recent years and the study of the deep waters of marginal seas is an important frontier research area.The South China Sea(SCS)is a typical marginal sea that includes Paleo SCS and New SCS tectonic cycles.The latter includes continental marginal rifting,intercontinental oceanic expansion and oceanic shrinking,which controlled the evolution of basins,and the generation,migration and accumulation of hydrocarbons in the deepwater basins on the continental margin of the northern SCS.In the Paleogene,the basins rifted along the margin of the continent and were filled mainly with sediments in marine-continental transitional environments.In the Neogene–Quaternary,due to thermal subsidence,neritic-abyssal facies sediments from the passive continental margin of the SCS mainly filled the basins.The source rocks include mainly Oligocene coal-bearing deltaic and marine mudstones,which were heated by multiple events with high geothermal temperature and terrestrial heat flow,resulting in the generation of gas and oil.The faults,diapirs and sandstones controlled the migration of hydrocarbons that accumulated principally in a large canyon channel,a continental deepwater fan,and a shelf-margin delta.展开更多
Tectonic activity occurred during the depositional period of the Enping Formation in the southern Baiyun Sag in the Pearl River Mouth Basin,with a series of synsedimentary faults and a set of large fan delta reservoir...Tectonic activity occurred during the depositional period of the Enping Formation in the southern Baiyun Sag in the Pearl River Mouth Basin,with a series of synsedimentary faults and a set of large fan delta reservoir bodies developing.There is no data from drilling,cores,etc.for this area,so this paper applies three-dimensional seismic data to study the structural style of the steep slope zone,the seismic facies characteristics of fan deltas,and the source-sink system and sedimentary model of the Enping Formation.The control action of tectonic activity on fan deltaic sedimentary systems is studied by combining interpretation of fault systems,dissection of structural styles,seismic reflection structure,seismic facies geometry,and seismic attribute analysis,together with theoretical analysis of the source-sink deposition process.The Baiyun Sag has experienced tectonic activity since the Eocene,and a series of synsedimentary faults are developed in the southern steep slope zone.Under the common control of multiple large synsedimentary faults,a large ancient gully formed in the steep slope zone in the south,which gradually widened from south to north.The uplift area in the southern part of the sag was exposed for a long time during the deposition of the Enping Formation and consequently suffered weathering and erosion.The resulting sediments were transported through a system of provenance channels composed of slopes and an ancient gully to the depression area,where they were deposited and eventually converged to form a large fan delta.The fan delta presents the overall characteristics of NS strong wedge reflection and EW strong domal reflection—thick in the middle part and thin in the wings.It displays a lobe-shaped distribution on the plane,with the fan root pointing to the south slope.According to differences in reflection intensity from bottom to top,it can be subdivided into three stages of progradational sedimentary bodies—the southern uplift and denudation zone,the large ancient gully,and the fan delta—which together constitute a complete source-sink system.This represents a sedimentary model of progradational fan delta under the overall joint control of the re stricted ancient gully and syndepositional faults.展开更多
基金Supported by the NSFC-Industry Joint Fund for Innovative Development(U24B2016)China National Science and Technology Major Project(2025ZD1402700)。
文摘For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system”based on the principles of systems theory.Integrating over 60 years of exploration achievements in the four major basins,the paper studies the basic geological conditions,hydrocarbon accumulation models and distribution characteristics of the system.With the core principle of“source-heat controlling natural gas and play-stratigraphy controlling accumulation”,it analyzes the distribution law of natural gas reservoirs covering“intra-sag,sag margin,extra-sag”and multi-stratigraphic sequences.The study shows that under the joint control of source and heat,the northern continental margin of the South China Sea can be divided into two major gas areas:the southern area dominated by coal-type gas and the northern area dominated by oil-type gas,with the former as the main body.Based on the distribution location of hydrocarbon kitchen,the total gas plays are classified into three types:intra-sag,sag margin and extra-sag.In the oil-type gas area of the northern coastal zone,the proportion of intra-sag natural gas is relatively high;in the coal-type gas area of the southern offshore zone,the proportions of intra-sag and sag margin natural gas are relatively large;while the scale of gas accumulation in the extra-sag plays is relatively small.Finally,it is clearly pointed out that the southern offshore zone is the main direction for the next natural gas exploration in the northern South China Sea.Specifically,in the offshore zone,the intra-sag play and middle-deep layers of the sag margin play in the Yingzhong sag should be focused for the Yinggehai Basin;the intra-sag play and sag margin play in the central depression are targets for the Qiongdongnan Basin;the middle-deep layers of the intra-sag play are targets for the Baiyun sag of the Pearl River Mouth Basin.Furthermore,in the northern depression zone of the Pearl River Mouth Basin within the coastal zone,the main exploration directions include the middle-deep layers of the intra-sag play in the Huizhou sag and the middle-deep layers of the intra-sag play in the Enping sag;in the Beibu Gulf Basin,the main directions are the middle-deep layers of the intra-sag play in the Weixinan sag and the middle-deep layers of the intra-sag play in the Haizhong sag.
基金supported by the National Science and Technology Major Project(Grant nos.2016ZX05026,2016ZX05026–007–007)the National Natural Science Foundation of China(Grant nos.91528303,41502127)+1 种基金the Opening Foundation of State Key Laboratory of Continental Dynamics,Northwest University,the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2017JM4013)the Scientific Team Foundation of Department of Geology,Northwest University,Xi’an。
文摘Deepwater oil and gas exploration has become a global hotspot in recent years and the study of the deep waters of marginal seas is an important frontier research area.The South China Sea(SCS)is a typical marginal sea that includes Paleo SCS and New SCS tectonic cycles.The latter includes continental marginal rifting,intercontinental oceanic expansion and oceanic shrinking,which controlled the evolution of basins,and the generation,migration and accumulation of hydrocarbons in the deepwater basins on the continental margin of the northern SCS.In the Paleogene,the basins rifted along the margin of the continent and were filled mainly with sediments in marine-continental transitional environments.In the Neogene–Quaternary,due to thermal subsidence,neritic-abyssal facies sediments from the passive continental margin of the SCS mainly filled the basins.The source rocks include mainly Oligocene coal-bearing deltaic and marine mudstones,which were heated by multiple events with high geothermal temperature and terrestrial heat flow,resulting in the generation of gas and oil.The faults,diapirs and sandstones controlled the migration of hydrocarbons that accumulated principally in a large canyon channel,a continental deepwater fan,and a shelf-margin delta.
基金supported by the National Science and Technology Major Project(Grant no.2016ZX05026–007–007)the National Natural Science Foundation of China(Grant no.41502127)+2 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(Grant nos.2017JM40132020JQ798)the Scientific Team Foundation of Department of Geology,Northwest University,Xian。
文摘Tectonic activity occurred during the depositional period of the Enping Formation in the southern Baiyun Sag in the Pearl River Mouth Basin,with a series of synsedimentary faults and a set of large fan delta reservoir bodies developing.There is no data from drilling,cores,etc.for this area,so this paper applies three-dimensional seismic data to study the structural style of the steep slope zone,the seismic facies characteristics of fan deltas,and the source-sink system and sedimentary model of the Enping Formation.The control action of tectonic activity on fan deltaic sedimentary systems is studied by combining interpretation of fault systems,dissection of structural styles,seismic reflection structure,seismic facies geometry,and seismic attribute analysis,together with theoretical analysis of the source-sink deposition process.The Baiyun Sag has experienced tectonic activity since the Eocene,and a series of synsedimentary faults are developed in the southern steep slope zone.Under the common control of multiple large synsedimentary faults,a large ancient gully formed in the steep slope zone in the south,which gradually widened from south to north.The uplift area in the southern part of the sag was exposed for a long time during the deposition of the Enping Formation and consequently suffered weathering and erosion.The resulting sediments were transported through a system of provenance channels composed of slopes and an ancient gully to the depression area,where they were deposited and eventually converged to form a large fan delta.The fan delta presents the overall characteristics of NS strong wedge reflection and EW strong domal reflection—thick in the middle part and thin in the wings.It displays a lobe-shaped distribution on the plane,with the fan root pointing to the south slope.According to differences in reflection intensity from bottom to top,it can be subdivided into three stages of progradational sedimentary bodies—the southern uplift and denudation zone,the large ancient gully,and the fan delta—which together constitute a complete source-sink system.This represents a sedimentary model of progradational fan delta under the overall joint control of the re stricted ancient gully and syndepositional faults.
