常规砂岩储层油水倒置成因分析

The Genetic Analysis of OilWater Inversion in the Reservoir of Routine Sandstone

锦州25-1油田沙二段油藏位于整体西倾的半背斜构造上,开发井钻后,沙二段Ⅳ油组气水界面较油顶高20 m。以地震资料、测井资料和动态资料为基础,综合研究认为该油组砂体是连通的,油水关系矛盾并非是由于沉积微相差异而导致的物性遮挡所致;通过对油气成藏时的受力分析,油水倒置主要是由于背斜构造内有一小的向斜构造,向斜构造导致该区域地层水在成藏过程中无法排出。后经生产动态证实,研究区为连通砂体,油水倒置,储量增大。

The reservoir of the second member of Shahejie formation is located in the half- anticline and the formation faces westward in Jinzhou 25- 1 oilfield. The gas- water interface is 20 m higher than the top of oil layer in the fourth oil layer in the second member of Shahejie. The sand is connected in this area through the seismic,well logging and production performance data. The reason of oil/water inversion is not caused by permeability barrier through the difference of microfacies. Mechanics analysis shows that there is a synclinal structure in the anticlinal structure and it causes oil/water inversion which leads to difficulty in draining off formation water in this area. The production performance confirms that the sand is connected in this area and oil and water reverses. At last,reserve volume increases.