Effects of Horizontal and Vertical Well Patterns during Waterflood in Anisotropic Reservoirs

Abstract

ABSTRACTUsing horizontal wells in a waterflood process, higher sweep efficiency is expected compared with the use of conventional patterns by vertical wells. However, the use of horizontal wells is very sensitive to the well pattern designed to operate the process. This paper presents an analysis of how the overall performance of a waterflood process is influenced by the well pattern using horizontal injector and producer in different configurations. The potential for a horizontal well application was assessed by numerical modeling for different scenarios in combinations of injection and production wells and reservoir anisotropy. Results from the study have demonstrated that significant amount of additional oil can be recovered and injectivity was remarkably improved by utilizing a combination of horizontal wells. The improvement of injectivity through a horizontal injection well was higher when it was combined with horizontal producer parallel to the injector. The overall performances in anisotropic reservoirs strongly depend on the type of wells considered and the orientation of the horizontal wells with respect to the permeability directions. Combination of horizontal wells placed parallel to the low permeability direction yields the best performance.