In order to clarify sandbody distribution patterns and hydrocarbon accumulation model of the Baijiantan formation in the Mahu sag,Junggar basin,and evaluate its hydrocarbon exploration prospects,the drilling,logging,seismic and experimental data were compre-hensively analyzed to understand the sedimentary patterns and hydrocarbon accumulation characteristics of the second member of the Baiji-antan formation(Bai-2 member).It is found that the Bai-2 member represents a braided-river delta-beach bar-turbidite fan sedimentary se-quence,with three types of sandbodies of underwater distributary channel,beach bar and turbidite fan.Channel sandbodies are dominant in braided-river delta front;beach bar sandbodies are developed in shore-shallow lake;controlled by slope breaks,multiple turbidite fans are developed in deep lake to semi-deep lake,with turbidite fan sandbodies distributed in a lobate pattern.Thus,a sedimentary pattern of un-derwater distributary channel-beach bar-turbidite fan was established.Nine major strike-slip fault systems are found in the study area.Among them,three types of fault combinations such as through-type,associated-type,and relay-type strike-slip faults effectively connect the Permian Fengcheng formation source rocks and serve as efficient vertical pathways for hydrocarbon migration.The Bai-2 member fol-lows a hydrocarbon accumulation model characterized by strike-slip faults connecting source rocks,fault-sandbody configuration control-ling reservoir,and hydrocarbon enrichment in high-quality reservoirs.
NETL
NSTL
维普
万方数据
