沧东凹陷孔二段常非一体化成藏研究与实践

Research and practice on integrated hydrocarbon accumulation of conventional and unconventional oil and gas reservoirs in member 2 of Kongdian formation in Cangdong sag

沧东凹陷是大港探区第二大富油凹陷,总面积为4 700 km2,其中孔二段有效勘探面积1 500 km2,最大埋深5 000 m。其勘探主要经历了以构造理念为主的构造油气藏发现阶段和以岩性理念为主的岩性油气藏发现阶段,对于非常规油气藏的认识仅以单井出油气点的形式存在,没有进行深入的研究。近几年,以孔南1 760 km2三维地震数据体为依托,开展全凹陷构造、沉积储集层、烃源岩与成藏模式等的重建研究,揭示了孔二段独特的地质特征与成藏规律。通过对常规油气藏和非常规油气藏开展一体化成藏条件分析,建立了孔二段在有效烃源岩控制下形成常规油与页岩油有序分布、连片聚集,满凹含油的油藏模式,即:斜坡主砂体区形成岩性油藏,细粒沉积区源储互层形成页岩油藏,为下步勘探潜力区带优选提供了依据。

Cangdong sag is the second largest oil-rich sag in Dagang exploration area with a total area of 4 700 km2. The effective exploration area of member 2 of Kongdian formation is 1 500 km2,and the maximum buried depth is 5000 m. The exploration has mainly experienced the discovery stage of structural hydrocarbon reservoirs based on structural concept and the discovery stage of lithologic oil and gas reservoirs based on lithology concept. The understanding of unconventional oil and gas reservoirs exists only in the form of single well oil and gas production points,and no in-depth research has been conducted. In recent years,based on the 1 760 km2 seismic data volume of Kongnan,the rebuild studies of the whole sag structure,sedimentary reservoir,source rock and hydrocarbon accumulation pattern have been carried out,revealing the unique geologic characteristics and accumulation law of member 2 of Kongdian formation. With the analysis of the integrated hydrocarbon accumulation conditions of conventional oil and gas reservoirs and unconventional oil and gas reservoirs,a reservoir model of conventional oil and shale oil orderly distribution and continuous accumulation,and oil bearing in whole sag under the control of effective source rocks in member 2 of Kongdian formation was established. It means that the lithologic oil reservoirs are formed in the main sand body area of the slope,and the shale oil reservoirs are formed in the source-storage interbeds of the fine-grained sedimentary area,which provides a basis for the further exploration potential zone optimization.