海上气顶油藏屏障注水立体井网的构建

海上气顶窄油环油藏平行于流体界面，部署水平井取得了较好的避气控水效果，但开发中后期依旧面临气窜加剧、液量下降、开发方式亟需调整的难题。应用油藏数值模拟的方法，针对试验井组开展不同注水井型、水平井不同布井方向、水平井不同布井位置方案的对比，完成屏障注水立体井网的构建试验。试验结果表明，偏离中轴线靠近Ⅰ期油井40 m的水平井平行立体注采井网开发效果最好，相较于天然能量开发，可提高采收率7.8个百分点。依据井网优化结果开展三维物模实验，最终采收率达到43.1%，与天然能量开发模拟采收率34.2%相比，采收率提高8.9个百分点。物模实验确定了屏障注水的有效性，并量化了屏障注水的开发效果。下一步计划以井组试验、逐步推广的方式实现油田开发方式调整，可为相似油田屏障注水方案研究提供依据。

Construction of 3D well pattern for barrier water injection in offshore reservoirs with gas cap

The offshore reservoirs with gas cap and narrow oil ring are parallel to the fluid interface, and to deploy horizontal well in these reservoirs can achieve good effects in avoiding gas and controlling water, however, However, in the middle and late development stages, these reservoirs still face the difficulties in intensified gas channeling, decreased liquid volume, and urgent adjustment of development methods. By using the method of reservoir numerical simulation, for the testing well group, the comparison of different schemes referring different water injection well types, different horizontal well layout directions, and different horizontal well layout locations was performed, and the construction test of the 3D well pattern for barrier water injection was completed. The testing results show that the development effect of the parallel 3D injection-production well pattern with horizontal wells deviated from central axis and 40 m away from the phase I wells was the best, and the recovery rate was increased by 7.8 percent compared with natural energy development. According to the results of well pattern optimization, 3D physical simulation experiment was carried out, with an ultimate recovery rate of 43.1%, which was 8.9 percent higher than the recovery rate of 34.2% simulated by natural energy development. The physical simulation experiments confirmed the effectiveness of the barrier water injection and quantified the development effect of the barrier water injection. In the next step, it is planned to adjust the development mode in a pattern of well group test and gradual promotion, trying to provide a basis for the studying barrier water injection schemes in similar oilfields.