柴达木盆地昆北冲断带古隆起油藏特征及油气成藏条件

基于露头、钻录井、测井、地震、测试及分析化验等资料,综合分析认为昆北冲断带是在古地貌隆起背景上发育起来的、受昆仑山前和昆北Ⅰ、Ⅱ号断层控制的新生代古构造带,发育古地貌隆起、地层-岩性和背斜构造等多种类型圈闭,形成了多类型的油气藏。控制油气成藏的关键因素包括早期的古地貌隆起、良好的断层-不整合疏导体系、稳定的细粒区域盖层、充足的远源供给和断层持续活动导致的长期油气充注,从而形成了较大规模的油气藏。昆北油田的发现拓展了柴达木盆地油气勘探领域,深化了油气成藏认识。

Characteristics and accumulation conditions of paleo-uplift reservoirs in Kunbei thrust belt,Qaidam Basin

Based on outcrop, drilling, well logging, seismic, testing and analytical data, it is suggested that the Kunbei thrust belt is a Cenozoic palaeotectonic belt developing on a palaeogeomorphic uplift background and controlled by piedmont faults of the Kunlun Mountains,the KunbeiⅠ fault and KunbeiⅡ fault, where traps including palaeogeomorphic uplift, formation-lithology and anticline ones have formed various oil-gas reservoirs. Key factors controlling these hydrocarbon accumulations include early paleogeomorphic uplift, good fault-unconformity carrier system, regional stable fine-grained caprock, plenty of distal source supply and long-term oil and gas filling caused by continuous fault activities, thus a large scale of reservoirs is formed. The discovery of the Kunbei oil field has developed the oil-gas exploration domain of the Qaidam Basin and deepened our understanding on hydrocarbon accumulations.