In this paper,the type,vertical evolution,and distribution pattern of sedimentary facies of the Paleogene Dainan Formation in the Gaoyou Depression of the North Jiangsu Basin are studied in detail.Results show that fa...In this paper,the type,vertical evolution,and distribution pattern of sedimentary facies of the Paleogene Dainan Formation in the Gaoyou Depression of the North Jiangsu Basin are studied in detail.Results show that fan delta,delta,nearshore subaqueous fan,and lacustrine facies developed during the Dainan Formation period and their distribution pattern was mainly controlled by tectonics and paleogeography.The fan delta and nearshore subaqueous fan facies predominantly occur in the southern steep slope region where fault-induced subsidence is thought to have created substantial accommodation,whereas the delta facies are distributed on the northern gentle slope which is thought to have experienced less subsidence.Finally,the lacustrine facies is shown to have developed in the center of the depression,as well as on the flanks of the fan delta,delta,and nearshore subaqueous fan facies.Vertically,the Dainan Formation represents an integrated transgressiveregressive cycle,with the E2d1being the transgressive sequence and the E2d2being the regressive sequence.This distribution model of sedimentary facies plays an important role in predicting favorable reservoir belts for the Dainan Formation in the Gaoyou Depression and similar areas.In the Gaoyou Depression,sandstones of the subaqueous distributary channels in the fan delta and the subaqueous branch channels in the delta are characterized by physical properties favorable for reservoir formation.展开更多
Objectives:The sedimentary distribution of Ledong formation in Yinggehai basin is not clear.The combination of seismic data and seismic forward modeling can clarify the sedimentary distribution in this area.Methods:Th...Objectives:The sedimentary distribution of Ledong formation in Yinggehai basin is not clear.The combination of seismic data and seismic forward modeling can clarify the sedimentary distribution in this area.Methods:The seismic facies boundary is characterized by seismic configuration,and the seismic subfacies boundary is characterized by seismic attribute structure.The sand body thickness of Ledong formation is characterized by seismic forward modeling and well logging sand body statistics of relevant well sections.Finally,the plane distribution of sedimentary facies is summarized.Results and conclusions:(1)The overall seismic attributes of the Ledong Formation in the Yinggehai Basin are favorable,characterized primarily by moderate to strong reflections on both sides.However,the middle section is severely disrupted by faults,exhibiting weak reflection characteristics.(2)The Ledong Formation represents a shallow marine beach-dam depositional environment,with extensive sand body development.A significant beach-dam complex is developed in the central part of the study area.The core of the sand bodies is relatively pure in texture and possesses excellent physical properties,making it a promising reservoir for oil and gas.(3)Based on seismic facies,two gas-water models are summarized:sheet sand bodies and multiple sets of sand bodies.展开更多
基金financially supported by the National Natural Science Foundation of China (Grants Nos. 41272124 and 41402092)Natural Science Foundation (Youth Science Fund Project) of Jiangsu Province (BK20140604)+1 种基金the Fundamental Research Funds for the Central Universities (20620140386)the State Key Laboratory for Mineral Deposits Research of Nanjing University (Grant No. ZZKT-201321)
文摘In this paper,the type,vertical evolution,and distribution pattern of sedimentary facies of the Paleogene Dainan Formation in the Gaoyou Depression of the North Jiangsu Basin are studied in detail.Results show that fan delta,delta,nearshore subaqueous fan,and lacustrine facies developed during the Dainan Formation period and their distribution pattern was mainly controlled by tectonics and paleogeography.The fan delta and nearshore subaqueous fan facies predominantly occur in the southern steep slope region where fault-induced subsidence is thought to have created substantial accommodation,whereas the delta facies are distributed on the northern gentle slope which is thought to have experienced less subsidence.Finally,the lacustrine facies is shown to have developed in the center of the depression,as well as on the flanks of the fan delta,delta,and nearshore subaqueous fan facies.Vertically,the Dainan Formation represents an integrated transgressiveregressive cycle,with the E2d1being the transgressive sequence and the E2d2being the regressive sequence.This distribution model of sedimentary facies plays an important role in predicting favorable reservoir belts for the Dainan Formation in the Gaoyou Depression and similar areas.In the Gaoyou Depression,sandstones of the subaqueous distributary channels in the fan delta and the subaqueous branch channels in the delta are characterized by physical properties favorable for reservoir formation.
文摘Objectives:The sedimentary distribution of Ledong formation in Yinggehai basin is not clear.The combination of seismic data and seismic forward modeling can clarify the sedimentary distribution in this area.Methods:The seismic facies boundary is characterized by seismic configuration,and the seismic subfacies boundary is characterized by seismic attribute structure.The sand body thickness of Ledong formation is characterized by seismic forward modeling and well logging sand body statistics of relevant well sections.Finally,the plane distribution of sedimentary facies is summarized.Results and conclusions:(1)The overall seismic attributes of the Ledong Formation in the Yinggehai Basin are favorable,characterized primarily by moderate to strong reflections on both sides.However,the middle section is severely disrupted by faults,exhibiting weak reflection characteristics.(2)The Ledong Formation represents a shallow marine beach-dam depositional environment,with extensive sand body development.A significant beach-dam complex is developed in the central part of the study area.The core of the sand bodies is relatively pure in texture and possesses excellent physical properties,making it a promising reservoir for oil and gas.(3)Based on seismic facies,two gas-water models are summarized:sheet sand bodies and multiple sets of sand bodies.
