Research On Optimum Well Spacing For Cyclic Steam Stimulation In Heavy Oil Reservoir Development

Steam-based thermal recovery processes, particularly, cyclic steam stimulation (CSS),are most extensively used in heavy oil development. For CSS recovery technique,determination of optimum well spacing is indispensable.A calculation procedure is presented to determine the heated volume based on the energybalance, using analytic model to determine the optimal well spacing. Before, manyresearchers have already proposed successful analytic models to calculate the heated volume.However, those models do not consider the influence of heavy oil rheology. Many paperspublished during this decade, however, indicate that below critical temperature point, theheavy oil flow does not apply to the Darcy law any more due to its own complexcomposition，therefore heavy oil shows Non-Newtonian characteristics.Two types of Non-Newtonian fluids, pseudo plastic fluid and power law fluids, and theirinfluences on the volume of heated area are investigated. Then, a new calculation procedure ispresented and carefully validated for vertical and horizontal well respectively.Finally, sensitivity analysis of rheology parameters, reservoir-fluids parameters andinjection parameters to well spacing is conducted. Combined with economic concerns, acomprehensive calculation procedure for determining optimum well spacing is proposed.