Abstract: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.