Optimal completion for horizontal injector and producer

Abstract

Horizontal wells have long been used to improve hydrocarbon recovery efficiency in waterflooding process because they provide better sweep efficiency than conventional vertical wells. Many waterflooding studies modeled the horizontal wells as non-friction wells, which overestimated the well performance. Due to friction pressure loss along the horizontal section, there exists a high pressure difference between the wellbore and the reservoir near the heel and low pressure difference near the toe of the injector and producer, generating a non-uniform water front. This results in reduction of areal sweep efficiency and early breakthrough. In order to keep the flood front uniform, the well cannot be uniformly completed but must be carefully designed for closed and open intervals. The completions that give rise to uniform front of water flowing out of the injector to the producer are referred to as optimal completion. In this study, a reservoir simulator was used to develop the optimal completion along the horizontal length via multi-segment well model in a homogeneous reservoir. A methodology to develop such completion is described. Several simulation runs were performed under different operating flow rates and mobility ratios of the injected and produced fluids to determine which conditions the optimal completion has high impact on recovery improvement. The simulation results indicate that optimal completion is recommended over conventional completion with equally completed intervals when in case with high operating flow rate and high mobility ratio.