On the Reduction of Optimization Time in Simulation of Oil Reservoirs

Thermal recovery techniques including Fast-SAGD process increases the production efciency of heavy oil reservoirs. Effective parameters in this study included injection and production rates, height of the injection, production, and offset wells, production and injection cycles, and pressure of the offset wells. In this study, optimization studies were performed. The objective function was defned as the cumulative steam injection to the produced oil to recovery factor. As optimization studies is a time- consuming process, discretized form of effective parameters were applied in this study.Three methods of discretization were selected including linear, square, and logarithmic techniques and their results were compared. In this approach, discretization was based on the results of sensitivity analysis without the exact recognition of the reservoir parameters. Applying this technique, the optimization speed increased three times while the accuracy of the results remained constant. The difference between the optimization results in the continuous and discrete states was less than 3%. Moreover, simulation results of the fast-SAGD process with two cycles were presented in terms of RF, CSOR, temperature and pressure distributions, and the produced oil from SAGD and injected steam to the offset well.