柴达木盆地昆北冲断带古隆起油藏特征及油气成藏条件

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

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。

Based on outcrop, drilling, well logging, seismic, testing and analytical data, it is suggested that the Kunbei thrust beh is a Cenozoic palaeotectonic belt developing on a palaeogeomorphic uplift background and controlled by piedmont faults of the Kunlun Mountains,the Kunbei I fault and Kunbeil] 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.