石臼坨凸起南斜坡区古近系成藏规律

FORMING LAWS OF EOGENE RESERVOIR ON SOUTH SLOPE OF SHIJIUTUO SWELL

渤中凹陷是渤海湾盆地最大的生烃凹陷，位于渤中凹陷北侧的石臼坨凸起在潜山继承性发育的新近系背斜上发现了数亿t的石油地质储量，而处于亿t级油气田群油气运移必经之路上的石臼坨凸起南斜坡区的钻探成果十分有限，成藏规律研究相对不足。在对石臼坨凸起南斜坡区层序地层研究的基础上，对其成藏条件进行了认真分析，明确了石臼坨凸起南斜坡区的成藏规律：主要目的层系为古近系，新近系油气藏主要在具有断穿馆陶组以下断裂附近富集；石臼坨凸起边界断层和斜坡区油源断层附近是寻找新近系油气藏的有利区域；相对洼陷区具有古隆起构造背景的区域是寻找大型气藏的优良场所。

Bozhong Sag is the largest hydrocarbon-generating sag in Bohai Bay Basin. Hundreds of million cubic meters OOIP have been discovered on the Neogene anticline successionally developed in buried hill on Shijiutuo Swell in North Bozhong Sag, while the exploration results of South Slope in Shijiutuo Swell are very limited, on which is the only way to hydrocarbon migration for hundreds of million tons of oil and gas group and furthermore the studies of the reservoir forming laws are relatively deficient. On the basis of the sequence stratigraphy study on the slope, the conditions of the reservoir formation are seriously analyzed and finally the forming laws have been made clear： the main target series of strata in the area belong to Eogene system, while Neogene hydrocarbon reservoirs are principally enriched nearby the faults that penetrate the strata below Guantao Formation; the regions near the boundary faults of Shijiutuo Swell and the oil-source faults of the slope are favourable areas to search for Neogene hydrocarbon reservoirs; the region having palaeohigh-structure background in the comparative sag area is good place for the discovery of large-scale gas reservoirs.