Study On Profile Control And Flooding Technology Of Nitrogen Foam And Its Applicability

Profile control and flooding technology of nitrogen foam is an effective improved oil recovery method for heterogeneous reservior at the later stage of development, and a series of studies and field experiments has been done in recent years. But it is at development stage and needs deep study in mechanisms of foam flow in porous media, influential factor and applicability. Therefore, it is important for improving application effects to develop the profile control and flooding technology of nitrogen foam and analyze its applicability. Based on the mechanisms of foam flow in porous media, a new parameter of foam comprehensive value was employed to evaluate foamers, which denoted the comprehensive characteristic of foamer's foaming ability and stability. Several foamers used in oil field were evaluated through experiment. The effects of gas-liquid ratio, oil saturation and permeability on nitrogen foam flow law in porous media were studied systemly. Oil saturation is the main influential factor of foam's fluidity, and just for this, the aggravation of formation heterogeneity has little effect on the effect of the profile control, foam's flow law is decided by remaining oil distribution. And the application effects of profile control and flooding technology of nitrogen foam, polymer flooding and enhanced profile control and flooding technology of nitrogen foam were evaluated. Profile control and flooding technology of nitrogen foam and enhanced profile control and flooding technology of nitrogen foam are more effective than polymer flooding in harmonizing mobility and improving sweep volume, but the later is more effective in improving oil recovery of high permibility core. The enhanced profile control and flooding technology of nitrogen foam is more effective than the profile control and flooding technology of nitrogen foam in improving oil recovery of high permibility core. The effects of foam flow on sand production were studied in the paper. Foam has stronger ability of carrying sands than water, not only because of high viscosity but also because of the expansion of foam at the outlet. The capillary bundle model was employed to study the flow law and its influential factor of Herschel-Bulkley fluid in porous media. And based on this, the foam's nonlinear flow was studied, and the results can be used to explain the results of experiments, and there is an optmum injection pressure for profile control and flooding technology of nitrogen foam to get maximum recovery ratio. The effects of reservoir conditions and production factors on profile control and flooding technology of nitrogen foam were studied through numerical simulation, the results show that the technology is more suitable for the heterogeneous reservoir of positive rhythm, good connectedness.