The impact of permeability heterogeneity on water-alternating-gas displacement in highly stratified heterogeneous reservoirs

Abstract Availability of gases at the field level makes attractive to water-alternating-gas (WAG) process for low viscosity and light oils carbonate reservoir. However, impact reservoir heterogeneity on WAG performance is crucial before application. In general, ramp carbonates have due variation permeability porosity. significantly affected by variations. This article investigates merits demerits displacement heterogeneities such as anisotropy, high streaks (HKS), matrix permeability, dolomite thin dense stylolite layers. High-resolution compositional simulations with tuned equation state (EoS) were carried out using 2D 3D sector models. The study focuses in terms oil recovery, vertical sweep, solvent utilization, gas ratio (GOR), water cut (WCT), response time, gravity override, hysteresis, un-contacted saturation economics. results simulation show that heterogeneous provides initially faster response, lower expected ultimate recovery (EUR), breakthrough, higher GOR WCT production compared homogeneous override smaller wells spacing less reservoir, but it reverse case larger well spacing. HKS shows significant resulting poor sweep capillary holding, layer early breakthrough. has utilization initial stage, then, becomes nearly equal Simulation both reservoirs overestimates incremental 2–3% OOIP one pore volume injection because not involving predicted core flood. findings this will help understand design highly applications. Graphical abstract