STRUCTURAL FRAMEWORK EVOLUTION IN SHIWU FAULT DEPRESSION AND ITS RELATION TO OIL AND GAS

The Shiwu Fault Depression in the south part of Songliao Basin is a halfgraben-like depression having been formed through evolving since Late Jurassic,being mainly undergone the following processes:Huoshiling Formation-Yingchang Formation fault depression sedimentation; rising and being eroded at the sedimentary end of Yingchang Formation;Denglouku Formation fault depression sedimentation;the rising,strike-slipping,and fault-blocking at the sedimentary end of Denglouku Formation;Quantou Formation-Nenjiang Formation depression sedimentation;and the compressional rising and strike-slipping at the sedimentary ends of Nenjiang Formation and Mingshui Formation.Therefore the properties of multiphase structural superposition and multistage reservoir formation are displayed.On the basis of comprehensively analyzing the structural framework evolution and source-rock burial history in Shiwu Fault Depression,the favourable oil and gas zones and traps are evaluated in the paper.