德阳—安岳裂陷东侧震旦系灯影组四段储层差异化发育机理与预测OA

Reservoirs of the 4th Member of the Sinian Dengying Formation(Deng-4 Member)around the Deyang-Anyue intraplatform rift in the Sichuan Basin are highly heterogeneous,alongside with unclear genesis and distribution of high-quality reservoirs.This study investigates the reservoirs of the Deng-4 Member in the Ningqiang area in the northern segment of eastern side of the rift,compares them with those in the Penglai area in the central segment and the central Sichuan paleouplift in the southern segment,and analyzes the differential development mechanisms of reservoirs on the eastern side of the rift.First,the Deng-4 reservoirs are facies-controlled,with stromatolite,framestone,and thrombolite dolomites serving as the main carriers of reservoir hosts.The preservation of pores was mainly controlled by early dolomitization,acid generation from microbial organic matter,a burial history characterized by prolonged shallow burial followed by late-stage accelerated deep burial,and early hydrocarbon charging.Second,the reservoirs show a differential pattern of development.The rimmed platform-margin reservoirs in the southern and northern segments of the rift have better development than the extensional fault-step platform-margin reservoirs in the central segment of the rift.The mode of prolonged shallow burial followed by late-stage accelerated deep burial in the northern segment is more conducive to the preservation of pores compared to the mode of continuous and uniform burial in the central and southern segment.Third,during the deposition of the lower-upper Deng-4 Member,the platform-margin microbial mound-shoal complex prograded from east to west perpendicularly to the platform-margin belt,and migrated from south to north parallelly to the platform-margin belt.The lower Deng-4 reservoirs are mainly distributed in the central and southern segments,the middle Deng-4 reservoirs in the central segment,and the upper Deng-4 reservoirs in Langzhong-Wangcang area of the northern segment and Penglai area of the central segment.These insights reveal that the Langzhong-Wangcang area in the northern segment of the rift,the central Sichuan paleouplift in the southern segment and the Penglai area in the central segment,has great potential of reservoir development in the Deng-4 Member.