Oil viscosity variation and its effects on production performance in water drive reservoir

The oil viscosity increases with the water cut in the process of waterflooding development.In the current commercial simulators for water drive reservoirs,the oil viscosity is treated as a unary function of pressure without considering other factors' effect.To improve the accuracy of numerical simulation,a new mathematical model,in which the oil viscosity changes with water-cut,is presented based on the black-oil model,and a new numerical simulator is developed.The production performance at different ranges of oil viscosity variation was studied with the oil field examples run on the simulator.The study shows that the increase in oil viscosity in the process of water drive results in the shortening of water-free oil production period,the acceleration of water-cut increase and the reduction in oil recovery.The accuracy of the model is tested by an oilfield example.