油藏水平井数值模拟研究中一种新的求解方法

A NEW MODEL FOR NUMERICAL SIMULATION OF HORIZONTAL WELL

提出了底水油藏水平井油水两相渗流问题的物理模型和数学模型，并建立了差分方程，然后利用ＩＭＰＥＳ求解方法的思路，并对其不足之处进行了改进，从而形成了一种新的求解方法．这种方法是采用上游网格饱和度插值计算相邻网格间的水量交换，用本阶段时间中点的饱和度对压力方程进行再迭代．保持了ＩＭＰＥＳ方法简单方便、占计算机内存少、计算速度快的优点，而精度明显提高，结果更趋合理．实际计算表明，新方法效果良好，可广泛用于底水、边水或人工注水油藏油水两相渗流问题的数值模型研究，对水平井和垂直井均适用．

This paper presents a physical model and a mathematical model for a horizontal well in a reservoir with bottom～water,considering gravitational and capillary force,Anew solving process was obtained by making two important improvements on the IMPESmethod.The new process used the interpolation and extrapolation of upstream saturation tocalculate water percentage,and used the saturation of the tniddle point of a time period toperfOrm re·iteration for pressure equations。The new method was used to calculate the productivity of a horizontal well.The resuits basically fit in well with the actual characteristicsof the saturation at water -oil disolacement front.Simulation of an actual horizontal well wasperformed,which showed the satisfied effect of the new process.