基于有限差分的化学剂平面运移规律数值模拟

Numerical Simulation of Chemical Planar Transport Based on Finite Difference Method

在化学驱中,各种化学剂在地层中的浓度对于驱油是极为关键的,理想的情况是合理设计化学剂注入参数(注入浓度、注入量和注入速度),使得地层各处化学剂的浓度接近实验室设计的最佳浓度,从而驱油效率最高。化学剂在地层中除正常的对流外,还会发生扩散和吸咐,而平面渗流中,各处渗流速度的不同,使得化学剂在平面的浓度分布比一维情况复杂得多。依据有限差分法和雅可比迭代方法,根据达西渗流定律确定平面渗流速度场和压力场分布,再根据已求得的速度场结合化学剂运移的对流弥散方程,求解得到了化学剂的浓度场。数值模拟结果给出了不同时刻化学剂在地层中的浓度分布,并针对不同的运移滞后系数、弥散系数和化学剂注入量,分析了这些参数对于化学剂分布的影响。

In the chemical flooding process,the concentration distribution of chemical agents is essential for the displacement of oil.The ideal situation would entail carefully designed chemical injection parameters（injection concentration,injection volume and injection rate） so that the chemical agent concentration in the formation is close to the optimum concentration determined by laboratory tests,and thus achieving the most efficient oil displacement results.In addition to normal convection of chemical agents in the formation,diffusion and adsorption will also happen.While for planar percolation flow,the different percolation flow velocity leads to the chemical planar concentration being more complex than that of one dimension.In this paper,based on the Finite Difference Method（FDM） and Jacobian Method,according to Darc/s law,planar flow velocity and pressure field are determined.And combined with the solved velocity field equation and the chemical agent transport convection-diffusion equation,the concentration field of chemical agents is solved.Simulation results show chemical concentration at the different time.It also studies the influence on the distribution of chemical flooding for different parameters including migration-lag coefficient,dispersion coefficient and the volume of chemical injection.