考虑摩阻损失的稠油油藏水平井产能计算新方法

A new calculation method of horizontal well productivity in heavy oil reservoir considering friction loss

为了更准确地评价稠油油藏水平井产能,针对目前稠油油藏水平井产能公式大多未能同时考虑非牛顿流体特性和井筒摩阻的影响,导致模型的计算结果与实际误差较大的问题,运用等值渗流阻力法,结合非牛顿流体管流模型,推导出幂律型稠油油藏水平井产能计算公式,采用渐进分析法对新公式的适应性进行了对比评价。在此基础上,利用新公式研究了稠油油藏水平井产能影响因素,结果表明:1)水平井越长,产能增加幅度越小,水平井超过600 m后,摩阻损失造成的产能降低将超过20%;2)幂律指数越小,水平井产能下降越明显,当幂律指数下降至0.9时,产能降低超过80%;3)矿场实例表明,考虑非牛顿流体管流摩阻的水平井产能计算公式误差仅为-5.77%。该研究成果为稠油油藏水平井开发提供了理论支撑。

In order to evaluate the productivity of horizontal wells in heavy oil reservoirs more accurately,aiming at the problem that the current productivity formulas of horizontal wells in heavy oil reservoirs fail to consider the effects of non-Newtonian fluid characteristics and wellbore frictional resistance at the same time,which results in a large error between the calculation results and the actual results,the productivity calculation formula of horizontal wells in power-law heavy oil reservoirs is deduced by using equivalent flow resistance method and non-Newtonian fluid pipe flow model.The adaptability of the new formula is compared and evaluated by using the progressive analysis method.On this basis,the factors affecting the productivity of horizontal wells in heavy oil reservoir are studied by using the new formula.The results show that:1)The longer the horizontal well is,the smaller the productivity increase is.After the horizontal well exceeds 600 m,the productivity reduction caused by friction loss will exceed 20%;2)The smaller the power index is,the more obvious the decline of horizontal well productivity is.When the power-law index drops to 0.9,the productivity decreases by more than 80%;3)Field examples show that the error of horizontal well productivity calculation formula considering non-Newtonian fluid pipe flow friction is only -5.77%.This research results provides theoretical support for horizontal well development in heavy oil reservoirs.