Producer/Injector Ratio: The Key to Understanding Pattern Flow Performance and Optimizing Waterflood Design

This paper presents new analytical relationships describing pattern waterflooding that have not been reported previously. The relationships fill a significant gap in the existing steady-state flow theory for two-phase, isotropic reservoir systems. The new equations, which include modifications for reservoir heterogeneity and skin effect, represent a general, comprehensive pattern flow theory that unifies previous works while greatly extending the range of applicability to all patterns and mobility ratios. These relationships facilitate understanding that is not provided by existing waterflooding theory of the absolute and relative flow performance of the various patterns in all mobility systems. A rational, analytical approach to waterflood optimization is presented here.