早期注聚开发油田水驱采收率计算方法

驱替特征曲线法是标定油田采收率的重要方法，对于早期注聚油田可以采用该方法计算聚驱采收率。为了解决早期注聚油田开发效果评价缺乏评价标准的问题，从影响驱替特征曲线线性段特征参数的主要因素入手，将室内水驱、聚驱相渗曲线测量结果与甲型驱替特征曲线相结合，导出了聚驱和水驱条件下驱替特征曲线线性段斜率和截距的数值关系，并由此给出了测算早期注聚油田水驱采收率的计算公式。实例油藏计算结果表明，水驱采收率可以达到29.14%，比早期注聚开发低15.07%；关于动用储量不变的假设，以及室内相渗曲线测量时聚合物溶液黏度与实际地层聚合物溶液黏度差异是影响本方法测算精度的主要因素。

A calculation method for waterflood recovery factor of oilfields developed by early polymer flooding

Displacement characteristic curve method is an important method to calibrate the recovery factor of oilfields, and it can be used in early polymer flooding oilfields to calculate their recovery factor of polymer flooding. At present, there is no evaluation criterion for the development effects of early polymer flooding oilfields. To deal with this situation, the main factors influencing the characteristic parameters of the linear section of displacement characteristic curve were analyzed, and the relative permeability curves measured in water flooding and polymer flooding experiments and the Type A displacement characteristic curve were combined. And accordingly, the slope-intercept numerical relationships of linear section of displacement characteristic curve under polymer flooding and water flooding conditions were derived, and the formula for calculating the waterflood recovery factor of early polymer flooding oilfields was established. It is shown from the case calculation results that waterflood recovery factor can reach 29.14%, which is 15.07% lower than that of early polymer flooding. The main factors influencing the calculation accuracy of this method are the assumption of constant producing reserves and the viscosity difference between the polymer solution during the laboratory measurement of relative permeability curves and the one in the real strata.