渤海海域石臼坨凸起大型岩性油气藏成藏关键要素

为探索渤海海域亿吨级岩性油气藏的主控因素，基于三维地震和钻井资料分析少井地区层序地层格架及极浅水三角洲岩性圈闭发育特征，结合晚期断裂体系及其实验模拟分析岩性油气藏成藏规律、成藏模式及其主控因素，剖析亿吨级岩性油气藏成藏的关键因素。建立了“脊-断-砂”三元控藏模式，即：①“汇聚脊”控制了油气初次运移聚集的优势部位，并决定油气运移调整至浅层的规模；②“脊-断”耦合控制油气进一步向浅层运移；③“断-砂”耦合控制大面积岩性圈闭发育以及油气充注程度。在该模式指导下，在石臼坨老区秦皇岛33-1小油田边发现秦皇岛33-1S新近系明化镇组亿吨级岩性油气藏。这是在高经济门槛限制下在渤海海域内岩性油气藏的首个商业性大发现。

Key factors for reservoir formation of large lithologic reservoirs in Shijiutuo uplift,Bohai Sea

In order to explore the dominant factors of hundred-million-ton lithologic reservoirs in Bohai Sea,based on three-dimensional seismic and drilling data,the sequence stratigraphic framework and the development characteristics of lithologic traps in extremely shallow water delta were analyzed. Combined with research and experimental simulation of late fault system,the reservoir-forming regularity,reservoir-forming model and main controlling factors of lithologic reservoirs were analyzed,and the key factors of reservoir-forming of hundred-millionton lithologic reservoirs were analyzed. A three-component reservoir control model of "ridge-fault-sand" was established. That is,the "convergent ridge" controls the dominant position of primary migration and accumulation of oil and gas,and determines the scale of oil and gas migration to shallow layer. "Ridge-fault" coupling controls the further migration of oil and gas to shallow layers,and "fault-sand" coupling controls the development of largescale lithologic traps and the degree of oil and gas filling. Under the guidance of this model,100 million tons of lithologic reservoirs of Neogene Minghuazhen Formation of QHD 33-1S have been discovered in the edge of QHD 33-1 small oil field in Shijiutuo old area. It is the first commercial discovery of lithologic reservoirs in Bohai Sea under the restriction of high economic threshold.