南堡凹陷周边古生界油气藏形成条件及成藏模式

为深入分析南堡凹陷周边地区碳酸盐岩油气成藏机理,笔者通过对区内碳酸盐岩的薄片鉴定、化学分析、烃源岩分析、物性分析、铸体压汞等实验测试和分析。结果表明,区内碳酸盐岩不具备生油能力,其油源为南堡凹陷古近系生油岩,且古近系生油岩生油母质较好、成熟度高、厚度大;碳酸盐岩基质孔隙度差,晶间孔欠发育,早期裂缝基本被充填完全,晚期构造裂缝为油气运移和聚集的主要空间;岩溶发育垂向分带不明显,溶蚀孔洞孤立且连通性差;区内主要发育有4类盖层,且储盖组合良好,发育有不整合油藏和构造块状油藏两种油气藏类型。

Hydrocarbon accumulation and models for the Palaeozoic reservoirs in the peripheral areas of the Nanpu depression

The investigation of the mechanisms for the hydrocarbon accumulation in the carbonate rocks in the peripheral areas of the Nanpu depression is made by means of the analysis of thin section,chemical property,source rocks,physical property and mercury-injection experiments of cast sections.The results show that the carbonate rocks in these areas are not capable of oil generation,and oil is mostly derived from the Palaeogene source rocks which have better types of organic matter,high maturity and tremendous thickness.The carbonate rocks are characterized by lower porosity of matrix and less-developed intercrystal pores.The early structural fractures have almost been filled,and only late ones may serve as the dominant reservoir spaces for the accumulation and migration of hydrocarbons.No vertical zoning is observed for the development of palaeokarsts,and the solution openings are isolated and poorly connected on the whole.There are four types of cap rocks dominated by mudstone(shale),constituting excellent seal-reservoir associations together with the reservoir rocks.The reservoir types consist of unconformable reservoirs and structural reservoirs.