地堑式断陷盆地油气成藏规律分析——以伊通地堑岔路河断陷南部为例

伊通地堑属佳—伊地堑的南段,是郯庐断裂带的北延部分,其内的岔路河断陷为一典型的地堑式断陷盆地.综合剖析表明,该断陷内的砂体主要为重力流性质的湖底扇沉积.湖底扇内扇中的水下泥石流或垮塌堆积砂砾岩对油气具有封堵性,湖底扇的中扇砂体具有一定的储集性能.内扇发育水下泥石流或垮塌堆积的湖底扇中扇砂体易于构成岩性圈闭.纵向上,此类断陷盆地具有广泛的含油性,易于形成多个含油层位;平面上,其有利勘探区带位于距控盆断裂一定距离的盆地两侧边缘区,特别是盆地盖层断裂有一定程度发育的边缘带,更有利于岩性油气藏的形成.油气勘探的目标主要为湖底扇中扇的舌状岩性油气藏和滚动背斜油气藏. 

ANALYSIS OF HYDROCARBON ACCUMULATIONRULE IN GRABEN STYLE BASIN——A CASE FROM SOUTH CHALUHE FAULT DEPRESSION OF THE YITONG GRABEN

Yitong Graben,subordinated to south section of Jia-Yi Graben,is the north-extension part of Tan-Lu Fault Zone.Chaluhe Fault Depression of the Yitong Graben is an graben style basin.According to comprehensive analysis,sublacustrine fan deposit which possesses gravity flow property is the domain sandstone sedimentary in this subsidence.Subaqueous debric flow or collapse-fall accumulational glutenite of inner fan has shut off capacity to hydrocarbon,while,the sandstone of middle fan,to some extent,has storage of hydrocarbon.The sandstone of middle fan is apt to form lithological trap,in case subaqueous debric flow or collapse-fall accumulation of inner fan is developed.Vertically,this style basin possesses comprehensive hydrocarbon potential and is prone to form multiple oil-bearing formations.Meanwhile,horizontally,the profit oil and gas exploration zone is located at basin both sides marginal zone which is away from controlling fault at some distance.Especially,the basin marginal zone where forms fracture is prone to form lithological reservoir.The exploration aim in this style basin should be focused on tongue-shaped lithological reservoir of middle fan and rolling anticline reservoir.