Optimization of polymer flooding in reservoirs under bottom-water condition to maximize economic profit

Abstract

Bottom-water condition has been considered as a challenging issue for implementing Enhanced Oil Recovery (EOR) techniques. In the application of polymer flood which is known as one of effective EOR methods, the existence of strong bottom aquifer leads to severe polymer loss to the aquifer, water fingering, and water production. Because these factors affect economics of the polymer flooding operation, injection design of the polymer flooding should be optimized to maximize profit. This study aims for the evaluation of polymer flooding under bottom water condition considering economic feasibility. Quantitative comparisons considering oil recovery, water production, and economics of polymer injection were made to obtain maximum net present value. The results indicated that oil recovery was increased 5% and water breakthrough was delayed about 40 days to maximize the net present value by 40%. After the optimization of injection designs, impacts of geological uncertainties on net present value were analyzed. According to sensitivity analysis, vertical permeability had most negative impact on the net present value. This study showed that injection of polymers under bottom water condition could be optimized to be an effective EOR technique for maximizing profit.