扎哈泉储层致密史与致密油聚集关系探讨

Relationship between Reservoir Densification History and Tight Oil Accumulation in Zhahaquan

扎哈泉是柴达木盆地西南部致密油勘探新区域,为深入认识致密油聚集规律,通过储层成因机理控制因素、成岩作用致密史模拟、致密油气充注及聚集成藏史分析,对储层致密史与致密油聚集关系进行了研究。结果表明:沉积作用的岩石学特征奠定了储层形成的物质基础,是致密储层形成的内因;压实、胶结等成岩作用是储层致密的重要外因;储层致密化时间为距今7 Ma;距今5 Ma致密油开始成藏,为Ⅰ期成藏。综合分析认为,扎哈泉致密油具有储层先致密油气后聚集、晚期成藏的地质特征。该研究对致密油地质认识及勘探具有重要指导意义。

Zhahaquan is considered as a new exploration area of tight oil in the southwestern part of Qaidam Basin. In order to further understanding the tight oil accumulation in this area,the reservoir genesis factors,densification history simulation of diagenesis,tight hydrocarbon charging and accumulation history are analyzed to study the relationship between tight reservoir densification history and tight hydrocarbon accumulation. Research shows that the petrologic properties of deposition lay a material basis for reservoir genesis,which is considered as an internal factor of tight reservoir genesis. Compaction,cementation and other diagenesis are considered as the major external factors of tight reservoir genesis. The densification time of tight reservoir is 7Ma ago. The tight hydrocarbon accumulation dates to 5Ma ago and is considered asⅠ-stage accumulation. Comprehensive analysis demonstrates that the tight reservoir in Zhahaquan is characterized by reservoir densification before hydrocarbon accumulation and late-stage hydrocarbon accumulation.This research could provide a significant guidance for the tight oil geology study and exploration.