塔西南坳陷奥陶纪构造活动与油气成藏  

Ordovician tectonic activities and oil and gas accumulation in the Southwest Depression of Tarim Basin

作　　者：崔海峰[1] 田雷[1] 刘军[1] 张年春[1] 

机构地区：[1]中国石油勘探开发研究院西北分院,甘肃兰州730020

出　　处：《石油地球物理勘探》2017年第4期834-840,850,共8页Oil Geophysical Prospecting

基　　金：中国石油天然气股份有限公司重大科技专项(041012120005)资助

摘　　要：塔西南坳陷奥陶纪构造活动与油气成藏关系密切。开展了近15×10~4km^2的地震资料构造解析,恢复了不同时期奥陶系鹰山组顶面构造形态,厘清了奥陶系顶面构造高点迁移特征,明确了奥陶纪构造活动与油气成藏的关系。研究认为,塔西南坳陷奥陶系顶面历经北倾向南倾和东倾向西倾的"跷跷板"式改造过程,发育调整迁移型古隆起,不利于油气的富集保存,构造活动的枢纽带是次生油气聚集带;其次,构造活动在奥陶系形成不同期次的断背斜圈闭,其中晚海西期和晚喜马拉雅期定型圈闭内发现油气,断裂是油气垂向运移的通道;第三,奥陶系鹰山组上段风化壳储层主要分布在断裂带,鹰山组下段内幕白云岩储层则分布较广,在靠近直立的走滑断裂附近最为发育,地震剖面上表现为"串珠"状反射;第四,奥陶系油气发现主要分布在南北向和东西向构造调整的枢纽带内,其中坳陷中段的东西向构造活动枢纽带是下一步油气勘探的有利区带,近期罗斯2井获得高产工业气流。Ordovician tectonic activities have a close relationship with oil and gas migration and accumulation in the Southwest Depression of Tarim Basin.Based on tectonic analysis on seismic data in an area of about 5×10~4 km,the top structures of Ordovician Yingshan formation in different geological periods are restored,its migration characteristics are clarified,and the relationship between tectonic activity and hydrocarbon accumulation is defined.The following observations are obtained:(1)The Ordovician paleo-uplift in the research area belongs to adjustment and migration type in which paleo-uplift underwent a process of strata dip leaning tilt north to south and east to west'seesaw'type adjustment migration,this is not conducive to oil and gas accumulation and preservation.Hinge zones of tectonic activities are secondary hydrocarbon accumulation zones;(2)Fault anticline traps were formed in different period under the Ordovician tectonic activities,and oil and gas had founded in the traps formed in the late Hercynian and late Himalayaperiod.Faults have become the channels for vertical hydrocarbon migration;(3)Weathering crust reservoirs in the Ordovician upper Yingshan formation are mainly distributed in fault zones,and inside dolomite reservoirs of the under Yingshan formation developed near vertical strike-slip faults on the slope zones which are characterized by bead-like seismic reflection on seismic sections.(4)Oil and gas discoveries were found mainly in hinge zones with south-north and east-west structure activities.The east-west hinge zone of Ordovician tectonic activities is a favorable area for further oil and gas exploration,and Well Luosi-2in this hinge zone has recently gained industrial gas flow.

关 键 词：塔西南坳陷 奥陶系 构造活动 枢纽带 碳酸盐岩储层 油气运聚 

分 类 号：P631[天文地球—地质矿产勘探]