马朗凹陷二叠系油藏赋存状态及裂缝分布

THE HYDROCARBON EXISTING STATE AND FRACTURE DISTRIBUTION REGULARITY OF THE PERMIAN RESERVOIRS IN MALANG SAG. SANTANGHU BASIN

三塘湖盆地马朗凹陷已发现的牛圈湖、黑墩和马中三个油田二叠系油藏控制石油地质储量达几千万吨。油藏综合分析表明,搞清二叠系油藏的油气赋存状态和裂缝分布规律是决定勘探是否取得成效的关键。根据油气显示、储层基质孔渗特征、压汞特征、荧光薄片以及压力测试资料等五个方面首先证明了在二叠系油藏中基质不仅普遍含油,而且是储集的主要空间。同时根据岩心描述、地层倾角和成像测井等资料对三个油田二叠系油藏的裂缝情况进行了全面细致的分析和描述,搞清了裂缝与岩性、与层厚以及与构造部位之间的关系,明确了裂缝在三个油田中分布的有利地区,提出了有效裂缝密度的大小是控制单井产量高低的主要原因这一重要论点,并最终指出牛圈湖、黑墩和马中油田二叠系油藏均为裂缝型油藏。这些结论为今后这三个油田的勘探评价、储量升级和开发可行性论证提供了重要的参考依据。

The controlled oil reserves in the Permian reservoirs of Niujuanhu, Heidun and Mazhong oil field discovered in Malang sag Santanghu basin have reached tens of millions tons. Comprehensive reservoir study shows that it is the key of exploration success to understand the oil existent state and fracture distribution regularity. Through careful study, the author premised that the matrix of the Permian reservoirs was not only oil-bearing, but also the major oil storage space. It was concluded that the density of effective fractures was the major factor that controlled the production per well, and the Permian reservoirs of Niujuanhu, Heidun and Mazhong oil field were all fracture reservoirs. These conclusions were important reference for the exploration evaluation, reserves upgrading and development feasibility study.