Analytical multiphase fluid flow model for reservoirs producing under bottom water drive mechanism

Abstract

The existing of transition zone in oil reservoirs causes alteration in pressure response of the producing wells and distorts the accuracy of the models which analyse the reservoir behaviour. An analytical multiphase flow model for oil reservoirs producing under bottom aquifer drive mechanism has been developed to predict the accurate reservoir pressure drop during the transient flow period, as well as the capillary-saturation relationship under reservoir conditions. The contacted fluids are linked across free water level which reflects the interaction degree between reservoir-aquifer rocks and their own fluid properties. The results show that the conventional flow models which assume single phase fluid flow in porous media or weighted rock and fluid properties mislead the accuracy in predicting reservoir pressure. The error of these models increases with increasing the interaction degree between the reservoir and the aquifer, which depends on both of reservoir-aquifer rocks and their own fluid properties.