博兴洼陷古近系沙四上和沙三段油气成藏的差异性研究

应用有机地球化学、高分辨率层序地层学和成藏动力学等研究方法，对博兴洼陷古近系沙四上亚段和沙三段两套烃源岩的油气成藏的差异性进行了研究。结果表明，虽然沙四上驱段和沙三段油气藏类型均为自生自储型的岩性或构造岩性油气藏，但是它们在烃源岩特征、储层特征、成藏机制和油气藏特征等方面存在着明显的差异。研究区沙四上亚段成藏组合的烃源岩有机质顺层富集，异常压力较高，多为微裂缝幕式排烃，排烃效率高，在洼陷中心及南斜坡有利圈闭位置处分别形成泥页岩裂缝型油气藏和滩坝型构造-岩性油气藏。而沙三段成藏组合的烃源岩有机质较分散，局部富集，异常压力相对较低，主要依靠差异突破压力进行排烃，排烃效率较低，油气藏类型主要为滑塌浊积型岩性油气藏，其次为三角洲前缘型构造-岩性油气藏和火山岩遮挡型油气藏。

Otherness on pool-forming in the upper E2s4 and E2s3 of Palaeogene in Boxing subsag

Two sets of oil-hearing series, the upper E2s4 and F2s3 of Palaeogene in Boxing sub.sag, were studied by adopting organic geochemistry, high-resolution sequence stratigraphy and pool-forming dynamics. The results indicate that there is noticeable othemess in the characteristics of source rock, reservoir rock and forming mechanism of oil pools, though reservoir types both of them are all lithologie or structural-lithologic. For the upper F2s4 source rock, there are some typical characteristics , including richness in organic matter along the formation bedding, higher formation pressure, more efficient hydrocarbon expulsion by rnicrofractures. The shale-cracked pools and the structural-lithologic pools of beach-dam can he formed respectively in the center and the south slope of the sag. But in the E2s3, the characteristics of source rock are distracting organic matter, only partly enrichment, lower formation pressure and less efficient hydrocarbon expulsion, which depends on differential breakthrough pressure. The lithologic pools of slip turbidite are in a majority, the structural-lithologic pools of delta front and the lava-screened pools are in a minority.