梨树断陷秦家屯—七棵树—太平庄沙河子组油气成藏规律

摘要

运用沉积、成藏、构造等手段,对梨树断陷秦家屯—七棵树—太平庄构造沙河子组隐蔽油气藏分布规律进行系统研究.结果表明,秦家屯地区沙河子组为扇三角洲和辫状河三角洲叠置沉积,发育构造油气藏;七棵树地区为湖相沉积和曲流河三角洲相沉积,发育构造-岩性复合油气藏;太平庄构造为辫状河三角洲沉积,油气远距离运移,以构造油气藏为主.研究区源岩母质类型为Ⅱ2-Ⅲ型,TOC平均值1.48％.活跃期的断裂可以作为油气运移通道,停止活动的断裂起遮挡作用,不能作为油气纵向运移通道.登娄库组末期构造运动时间早于油气成藏时间,油气大规模运聚发生在登娄库组沉积之后.%The authors undertake a systematic study on the distribution of oil and gas in subtle reservoirs of Qinjiatun,Qikeshu and Taipingzhuang area in Lishu depression through the work on sedimentation,accumulation and tectonics.It shows that the Shahezi Formation of Qinjiatun area is composed of superimposed fan delta and braided river delta deposits,with structural traps developed,whereas the Shahezi Formation of Qikeshu area consists of lacustrine facies and meandering river delta facies,with lithological-structural traps developed.The Shahezi Formation of Taipingzhuang area consists of braided river delta deposits,with oil and gas accumulated in structural traps.The source rocks in the study area are mainly type Ⅱ 2 ～ Ⅲ,and the average TOC is 1.48％.The active fault acts as the hydrocarbon migration pathway,but the inactive fault is blocking the further migration of oil and gas.The tectonic movement at the end of Denglouku Formation sedimentation occurred before the hydrocarbon accumulation.Therefore,large scale migration and accumulation of oil and gas occurred after the deposition of the Denglouku Formation.