普通稠油油藏反九点井网平面波及 系数计算方法及数模验证

综合考虑普通稠油油藏渗流过程中存在启动压力梯度和非活塞驱替以及井网处于非单一沉积微相时渗透率各项异性的特征,建立了一套普通稠油油藏反九点井网平面波及系数的理论计算方法,定量表征平面波及系数的变化规律,计算各方向边、角井的见水时间。研究了启动压力梯度、压差以及渗透率级差对平面波及系数和见水时间的影响。同时,自主编程了考虑启动压力梯度的油藏数值模拟器。结果发现:启动压力梯度越小,压差越大,水驱平面波及系数越大,边、角井见水时间越快,含水率越高;渗透率级差越小,波及越均匀,边井见水时间差越小。通过模拟,验证了理论计算方法的准确性,可视化了不同水驱阶段平面波及系数和剩余油饱和度的变化规律。通过优化注采参数、差异化边角井工作制度等方式,缩小了死油区,提高了平面波及系数,改善了水驱效果。

Calculation method and numerical simulation verification of areal sweep coefficient of inverse nine-point well pattern in general heavy oil reservoir

Considering the characteristics of threshold pressure gradient and non-piston displacement in the process of seepage in ordinary heavy oil reservoirs and the anisotropy of permeability in the non-single sedimentary microfacies, a theoretical calculation method for the areal sweep coefficient of inverse nine-point well pattern in a common heavy oil reservoir is established. The method can not only quantitatively characterize the variation law of areal sweep coefficient, but also calculate the water seeing time of each direction edge and corner well. The effects of threshold pressure gradient, differential pressure and permeability difference on areal sweep sum coefficient and water seepage time were studied. It is found that the smaller the threshold pressure gradient is, the larger the pressure difference is, the larger the sweeping coefficient of the water flooding areal is, the faster the water seeing time is, the higher the water content is; the smaller the permeability difference is, the more uniform the sweep is, and the time difference between the wells and the water sees. At the same time, the reservoir numerical simulator considering the threshold pressure gradient was programmed autonomously. The accuracy of the theoretical calculation method was verified by process of simulation, and the variation law of areal sweep sum coefficient and residual oil saturation in different water flooding stages was also visualized. By optimizing the parameters of injection and production, and the working system of differentiated corner wells, the dead oil zone is reduced, the areal sweep coefficient is improved, and the water flooding effect is improved.