济阳坳陷长堤地区走滑构造特征及对油气聚集的控制作用

Characteristics of strike-slip faults and its control on hydrocarbon accumulation in Changdi area of Jiyang Depression

济阳坳陷内部凸起区发育大量的潜山油气藏,但在长堤地区的长堤低凸起油气却未聚集于潜山,而是在浅层成藏。目前对该区油气成藏的成因机制研究较少,构造是控制其油气成藏的重要因素,为此基于研究区地震资料的精细解剖和石油地化资料的整理分析,对长堤地区走滑构造特征及其油气控藏作用进行分析。结果表明:长堤断层形成于新生代,具有明显的右旋走滑特征;断层中段为"S"型走滑增压弯曲段,断层面紧闭,地层受走滑挤压隆升,形成有利于油气聚集的小型背斜和断鼻构造;断层南段和北段为"S"型走滑释压弯曲段,断层面开启,破坏早期圈闭,不利于油气成藏。长堤低凸起走滑增压弯曲段油气成藏模式主要表现为浅层成藏,双源、多层系供烃和复式输导的特征。

A large number of buried hill oil reservoirs are developed in the inner uplifts of Jiyang Depression.However,hy drocarbon accumulates in shallow layers instead of the low uplift in Changdi area.At present,research on the genetic mech anism of hydrocarbon accumulation is insufficient in this area.The structure is an important factor controlling the hydrocar bon accumulation.For this reason,based on the detail seismic data interpretation and hydrocarbon geochemical data analy sis,the characteristics of the strike-slip faults and their control on the hydrocarbon are analyzed.The results show that Changdi fault is formed in the Cenozoic,with obvious dextral strike-slip.The middle part of Changdi fault is pressurization flexure in“S”shape of the strike-slip fault caused by pressure increasing,the fault plane is tightly closed,and the strata are compressed and uplifted to form small anticlines and fault-nosed traps.The southern and northern part of Changdi fault is depressurization flexure in“S”shape of the strike-slip fault caused by pressure releasing,the fault plane is opened and destroys the early traps,which is not conducive to hydrocarbon accumulation.The hydrocarbon accumulation mode in strike-slip compressed sections in Changdi low uplift is mainly characterized by shallow hydrocarbon accumulation,multihydrocarbon sources supply and multi-transportation pathways.