Enhancing Sweep Efficiency and Delaying Water Breakthrough in Carbonate Reservoir: The Impact of Polymer Flooding

This article addresses the crucial task of optimizing sweep efficiency in the carbonate Mishrif reservoir of the Buzurgan oil field through the application of Polyacrylamide and Xanthan gum polymers. The study thoroughly investigates rheological properties, including viscosity, shear rate impact, and concentration effect. Experimental measurements using a viscometer are complemented by advanced Petrel and Eclipse software for simulation studies, examining the dynamic interplay of concentration, viscosity, and shear rate on key reservoir parameters. Key findings reveal a consistent increase in xanthan gum solution viscosity as shear rates decrease from 600 RPM to 3 RPM. Significantly, at higher polymer concentrations (0.75 gm/L to 2.5 gm/L), viscosity continues to rise, presenting an advantage over polyacrylamide. Simulation outcomes highlight the positive impact of increased polymer concentration and viscosity on sweep efficiency, translating to higher oil recovery factors. Optimal concentrations for xanthan gum polymer (0.123 kg/m3 under strategy-8) and polyacrylamide polymer (0.14 kg/m3 under strategy-2) demonstrate superior final field oil production cumulatively, surpassing water flood strategy by 6.3 MMSTB and 6.6 MMSTB, respectively. The study underscores the economic and strategic advantages of employing polymer flooding in reservoirs utilizing an inverted nine-spot pattern over peripheral patterns. The novelty lies in the detailed exploration of rheological properties and simulation studies, offering specific and quantitative insights. This article significantly contributes beyond prior literature by providing actionable recommendations, refining our understanding of polymer flooding dynamics, and tailoring strategies for reservoirs with distinct patterns and characteristics.