多因素影响的泡沫驱数值模拟方法

基于泡沫封堵规律实验结果和质量守恒定律，建立了综合考虑多孔介质渗透率、发泡剂质量浓度、泡沫干度、油藏温度、含油饱和度、含水饱和度以及渗流速度等多因素影响的泡沫驱数学模型。采用IMPES和Runge-Kutta方法对模型进行了求解和验证。利用数值模拟方法研究了泡沫封堵特性和泡沫驱开发效果影响因素的敏感性。研究结果表明：随着转驱时机的推迟，最终采收率先小幅升高后迅速降低；随着泡沫干度增加，最终采收率先增加后降低，泡沫干度为50%~67%时的驱替效果最佳；随着发泡剂质量浓度增加，最终采收率先迅速增加后趋于稳定；随着注入速度增加，最终采收率先增加后降低；各因素对泡沫驱最终采收率影响程度大小为：发泡剂质量浓度>注入速度>泡沫干度≈转驱时机。由于该数学模型考虑了众多与实体油藏相关的参数，所以该模拟方法可以更容易、有效地应用于指导泡沫驱矿场试验方案的制定。

Numerical simulation of foam flooding influences of multi-factors

Based on the experimental results of foam blocking rules and mass conservation law, a mathematical model of foam flooding is established by considering the influences of multi-factors including permeability, foaming agent concentration, foam quality, reservoir temperature, oil saturation, water saturation, and flow velocity in porous media. The model is then solved and validated with a reservoir simulator which is formulated using a combination of the implicit pressure explicit saturation method and a Runge-Kutta method. The simulator is further used to examine the blocking characteristics of foam and the sensitivity of factors influencing oil recovery of foam flooding. Results show that: (1)As the starting time of foam flooding is postponed, the ultimate recovery first increases slightly and then decreases sharply. (2)With increasing foam quality, the ultimate recovery also shows increases followed by decreases, with an optimal value of 50 % -67 % for foam flooding. (3)With increasing foaming agent concentration, the ultimate recovery increases rapidly to reach a plateau. (4)With increasing injection rate, the ultimate recovery first increases and then decreases. (5)The multi-factors affect the ultimate recovery of foam flooding to different extents in descendent order of foaming agent concentration, injection rate, foam quality and starting time of foam flooding. Since the mathematical model incorporates multiple oilfield-associated parameters, it can guide the design of foam flooding programs in field tests more easily and effectively.