西泉地区石炭系南北油气地质条件及成藏模式差异分析

Different Geological Conditions and Accumulation Modes of Carboniferous between the South and North Belt in Xiquan Area

西泉地区位于准东北三台凸起高部位,研究目的层位为石炭系巴山组,岩性以火山岩为主,夹部分碎屑岩。根据西泉地区的构造特征,以位于研究区中心位置的2条大断裂为界,将研究区分为南北2个构造带,并从油藏地质条件及成藏模式方面分析了南北油气成藏差异。南部构造带构造运动复杂,储集条件好,产量高,油气来源于阜康凹陷平地泉组,沿不整合面上发育的鼻隆构造运移,并在鼻隆构造上的断层—地层型圈闭及残丘型圈闭成藏;北部构造带构造活动较弱,风化残丘构造发育,压力系数较南部低,油气也来源于阜康凹陷平地泉组并沿整个不整合面运移至其顶面风化残丘型圈闭中成藏。

Xiquan Area is located in the high part of Beisantai,the target strata are Carboniferous Bashan Formation,the dominated lithology is volcanic rock,and clastic is included.According to the structural characteristics of Xiquan Area,divided by the two major faults in the center,the study is divided into two belts,the southern and north belt,the differences of hydrocarbon accumulation in geological conditions and accumulation model are analyzed.For the southern belt,the tectonic movement is complicated,the reservoir condition and output are very good,the oil and gas which come from the Pingdiquan Formation in Fukang Sag and moving along the nose in unconformable surface are gathered in the Fault-stratigraphic and weathered-remaining hillock traps;for the northern belt, the tectonic movement is simple,the weathered-remaining hillock tectonics are widely developed,and the pressure coefficient is lower than that in the south,the oil is also derived from the Pingdiquan Formation in Fukang Sag,but moves along the entire unconformable surface to the weathered-remaining hillock traps.