Simplified methods of modeling multilayer reservoirs

Abstract

The purpose of this study is to develop simplified methods to model multilayer reservoirs. We examined the method to model well responses of multilayer reservoirs with equivalent single layer solutions during transient flow period which Bennett and Camacho suggested for hydraulically fracture wells. We also examined modeling responses of wells with positive skin factors completed in multilayer reservoirs with equivalent single layer solutions. More specifically, this work examined the boundary-dominated pressure response of vertically fractured wells producing from conimingled reservoirs irrespective of whether the boundary sizes and fracture lengths are equal or unequal. We developed techniques to model multilayer reservoirs with single-layer solutions during the boundary-dominated flow period. We also examined modeling the pressure response during pseudosteady state flow in a multilayer system with skin factors in individual layers using a single layer solution which includes an equivalent skin factor. In addition, we present step-by-step procedures to model well responses for homogeneous multilayer reservoirs and layered hydraulically-fractured wells with single layer solutions during transient flow and during pseudosteady state flow. Finally, we identified the minimum number of layers to which a multilayer, vertically-fractured reservoir can be reduced and show the same pressure response as the original system.