可动凝胶调驱快速模拟方法研究

Study of fast simulation method for flowing gel driving

为了解决目前可动凝胶深部调驱数值模拟计算速度慢、数值弥散现象严重的问题,针对高含水期油田开采的特点,建立了可动凝胶调驱的油水两相八组分数学模型。采用流线方法将求解饱和度的三维问题转化为一维问题求解。流线上的饱和度方程属于典型的对流扩散方程,采用算子分离算法将该方程分解成一个双曲型方程和一个抛物型方程,并采用各自稳定性好的差分格式分别求解,提高了求解的速度和精度。设计了一个正韵律剖面模型,对影响可动凝胶调驱的注入参数和地层参数进行了敏感性分析。结果表明,随着聚合物浓度、聚胶比、注入体积、成胶时间的增加,采收率提高幅度均有所增加;纵向窜流程度增加,可动凝胶调驱效果变好。

Problems of slow simulation speed and large numerical dispersion of simulators for weak gel driving are serious. Based on the characteristics of flowing gel driving during high water cut period, a new model for this simulation was established. The model is a two-phase （oil-water） and eight-compasition model. Streamline simulation method was used to solve the saturation equation by decoupling the full 3-D problem into multiple 1-D problems along streamline, The saturation equation along streamline is a typical convectior-diffusion equation. The conveetion-diffnsion equation was split into a hyperbolic equation and a parabolic equation by means of operator splitting algorithms. The finite difference method of fractional steps was used to solve the split equations, which improves the speed and accuracy of solution. A eros,s-section model for a thick bed of positive rhythm was established to analyze the sensitivity of formation and injection parameters. The results show that the enhanced oil recovery increases with the polymer con- centration, ratio of polymer and gel, injection volume and time of gel forming increasing, The effects of profile control and driving are improved when the channeling in vertical direction becomes serious.