Abstract:

Estuary bar sandstone body is also one of the most important types of oil and gas reservoirs in China,and its internal interlayers control the distribution and movement of fluid inside the reservoir and affect the overall development effect of the reservoir. Taking the fault block reservoir of Sha-2（S2） member of L11 fault block in Shinan oilfield as an example, the rock and layer type of intercalation in estuary bar sandstone body are analyzed by means of logging, core, analysis and dynamic production data, the spatial distribution law of intercalation is described, and the influence of intercalation on remaining oil distribution is expounded.The results show that the main oil layer of L11 fault block consists of mud, physical and calc interlayers, which account for 68%,21% and 11% respectively.The calc interlayers are concentrated in the distribution area of physical interlayers,and the development degree of physical interlayers is relatively high in the northeast near the provenance and the peak of the interlayer, while the development degree of mud interlayers is relatively high in the southwest far from the provenance. In the near-source direction, the fifth-order configuration interface is relatively thin, and in the far-source direction, the thickness is relatively thick, ranging from 0.60 m to 29.00 m. In the fourth-order interface, the drilling rate of interlayer is above 60%, the thickness is between 0.35 m and 4.10 m, and the inclination is less than 2.0°. The level 3 interfacial interlayer is spread no more than 3 well spacing, the thickness is less than 1.50 m, and the dip angle is 2.7° on average. Level 4 and 5 interfaces control the distribution of remaining oil,level 3 interface has little influence on the distribution of remaining oil, low injection and high production mode development effect is relatively good,high injection and low production mode development effect is relatively poor,through the injection and production mode can improve the well group oil displacement efficiency and development effect.The above results and understanding have important guiding significance for the efficient development of estuary bar sandstone reservoir.

Key words: Estuary bar, Interlayer, L11 fault block, Remaining oil

摘要：

以史南油田L11断块沙二段（S2）的断块油藏为例，运用测井、岩心、分析化验及生产动态资料，分析了河口坝砂岩体夹层的岩石及层次类型，描述了夹层的空间展布规律，阐明了夹层对剩余油分布的影响。结果表明，L11断块主力油层的泥质、物性和钙质夹层的占比分别为68%、21%、11%；钙质夹层集中发育在物性夹层分布区，距离物源较近的东北部、夹层尖灭处物性夹层发育程度较高，距离物源较远的西南部泥质夹层发育程度较高。近源方向5级构型界面较薄，远源方向较厚，厚度为0.60~29.00 m；4级构型界面夹层钻遇率在60%以上，厚度为0.35~4.10 m，倾角小于2.0°；3级构型界面夹层展布不超过3个井距，厚度小于1.50 m，平均倾角为2.7°。4级、5级构型界面对剩余油的分布起到了控制作用，3级构型界面对剩余油分布的影响较小，低注高采模式开发效果较好，高注低采模式开发效果较差，通过注采模式可以提高井组驱油效率及开发效果。以上成果及认识对河口坝砂岩油藏的高效开发具有重要的指导意义。

关键词: 河口坝, 夹层, L11断块, 剩余油