南堡凹陷周边凸起地区碳酸盐岩古岩溶与油气成藏

通过地层对比、野外露头剖面观测、单井岩心观察，样品测试等手段, 对南堡凹陷周边凸起地区的岩溶作用、成岩作用、油气成藏及控油因素进行了详细研究。结果发现，该区的岩溶作用较为发育，主要为：①野外露头见大的溶洞，岩心观察有岩溶角砾、溶蚀孔洞及黄铁矿集合体等；②录井表现为钻时突然降低甚至钻具放空，井漏；③测井解释有大型溶蚀孔洞发育带、溶蚀孔洞发育带等。成岩作用分为建设性成岩作用、破坏性成岩作用以及双重性成岩作用。油气藏类型主要有潜山不整合油气藏和构造块状油气藏，控制油气成藏的关键因素是岩溶缝洞型储层有效储集体发育程度、烃源岩的好坏及与构造的关系，尤其是油气运移通道是否发育直接影响了周边凸起有利部位的油气富集程度。

Palaeokarst of carbonates and hydrocarbon pooling in salients surrounding Nanbao depression

Based on stratigraphic correlation, outcrop measurements, single well core observation, and core sample testing, we studied in detail the karstification, diagenesis, hydrocarbon accumulation, and their controlling factors in the salients surrounding Nanbao depression. The study results show that karstification is relatively strong in the study area. ① Large caverns can be observed in outcrops, and karst breccia, solution pores and vugs and pyrite assemblages can be observed in cores. ② Abrupt drilling time decrease or even lost circulation exist. ③ Log interpretation reveals the existence of large and moderate solution pore vug zones. Three types of diagenesis can be recognized: constructive diagenesis, destructive diagenesis, and mixed constructive and destructive diagenesis. Buried hill unconformity reservoir and structural massive reservoir are the major reservoir types. The major factors controlling hydrocarbon pooling include the physical properties of the fractured vuggy karst reservoirs, the quality of source rocks and their relations with structures, especially the hydrocarbon migration pathways which directly control hydrocarbon enrichment in the favorable salients surrounding Nanbao depression.