鄂尔多斯盆地富县地区延长组长8~2油藏含油饱和度研究

Research on Oil Saturation of Chang 8~2 Reservoir of Yanchang Formation in Fuxian area of Ordos Basin

鄂尔多斯盆地富县地区延长组长8~2储层物性差、非均质性强,试油成功率低。为弄清本区长8~2油藏含油分布规律,利用岩心薄片资料与粒度分析相结合、扫描电镜与铸体薄片相结合,系统分析富县地区长8~2油藏岩石学特征。在此基础上,根据密闭取心、高温岩电数据分析研究区长8~2储层的含油性及其平面分布规律。结果表明,长8~2储层砂岩类型为长石砂岩,填隙物含量不高(平均7.1%),以绿泥石和方解石为主,物性较差,属于低(特低)孔-特低(超低)渗储层。长8~2储层密闭取心获得平均含油饱和度为39.3%,利用高温岩电和阿尔奇公式计算,长8^(2-1)小层和长8^(2-2)油饱和度分布范围32.0%~68.7%之间,含油饱和度呈条带状或片状分布于道主河道区域,且分布面积广、连片性好。

The Chang8^2 reservoir in Fuxian area of Ordos Basin has the characteristics of poor physical property, great heterogeneity and low success rate of well testing. The characteristics of reservoir petrology were analyzed by core slice and grading, cast sections, scanning electron.The distribution law ofoil in Chang8^2 reservoir was analyzed by method of sealing core drilling and high temperature rock electricity. The results show that feldspar sandstone is its main reservoir lithology. The main interstitial materials＇ content is not high with average of 7.1%, which are calcite and chlorite. The physical property of reservoir is low porosity and ultra-low permeability. The average oil saturation of Chang8^2 reservoir is 39.3% with sealing core drilling. The average oil saturation of Chang8^2-1 and Chang8^2-2 reservoir is in the range of 32.0%-68.7% with high temperature rock electricity. The main oil area is distributed in the area of underwater channel with the characteristics of good connectivity and wide distribution.