水驱开发油藏原油黏度变化规律及其对开发效果的影响

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

水驱油田开发过程中,原油黏度随含水率升高而增加。目前水驱油藏数值模拟器中简单地将原油黏度看成是压力的一元函数,没有考虑其他因素对原油黏度的影响。为提高模拟精度,在黑油渗流模型的基础上,建立了原油黏度随含水率变化的新模型,开发了新的数值模拟器,并在该模拟器上模拟了不同的原油黏度变化幅度对生产动态的影响。研究结果表明:水驱过程中原油黏度的升高缩短了无水采油期,加快了含水上升速率,降低了采出程度。油田实例对比验证了该模型的正确性。

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.