Comparison of the effectiveness of different modifications cyclic flooding of an oil reservoir

Abstract

The depletion of readily accessible oil has increased the focus on recovering harder-to-access reserves. Consequently, the industry requires new, improved, low-cost, and efficient methods for developing reservoirs with complex geological structures. Cyclic waterflooding provides simple and inexpensive approach for enhancing oil recovery. Operators have been utilizing cyclic waterflooding since the late 1950s in several regions of Russia, including Western Siberia, the Republic of Tatarstan, the Samara Region, Perm Krai, and Krasnodar Krai. Today, researchers abroad study cyclic waterflooding most actively in China. In this study, we examine two modifications of cyclic waterflooding: (1) cyclic water injection through injectors and (2) asynchronous cyclic waterflooding, which involves the simultaneous operation of both injection and production wells. We also study cyclic forced liquid withdrawal through a producing well. The aim of this work is to analyze the behavior of these three cyclic waterflooding modifications under different geological conditions. We analyze how each modification influences oil-saturation patterns in a two-dimensional synthetic reservoir model. Researchers and engineers should consider these results when designing cyclic-waterflooding programs for real reservoirs with complex geology. Our study reveals that the location of low-permeability layers near injection and/or production wells significantly impacts the effectiveness of cyclic waterflooding. When such layers are situated close to the production wells, relying solely on cyclic injection provides minimal benefits. The results indicate that asynchronous cyclic waterflooding offers the highest efficiency.