油水相对渗透率曲线预测模型建立及应用

油水相对渗透率曲线是油藏数值模拟中提高历史拟合精度和准确预测开发指标的关键参数。数值模拟中不同储层物性采用不同的相对渗透率曲线是十分必要的。以目标油田具有代表性的52条非稳态油水相对渗透率曲线为样本,利用交替条件期望方法,建立了束缚水饱和度、残余油饱和度、束缚水下油相渗透率和残余油下水相渗透率等端点值模型,结合油藏归一化平均相对渗透率曲线,形成了油水相对渗透率曲线预测模型。基于所建立的预测模型,可以得到目标油田不同储层物性对应的相对渗透率曲线,并应用于历史拟合过程中。历史拟合结果表明,历史拟合精度尤其是含水率急剧变化段的拟合精度有明显提高。该预测模型可广泛应用于相渗资料丰富的老油田的历史拟合和指标预测过程中,同时也为相对渗透率曲线网格化奠定了基础。

The Establishment and Application of Prediction Model for Oil-water Relative Permeability Curve

Oil water relative permeability curve is the key parameter to improve the accuracy of history match and to forecast the development law in reservoir simulation. Taking 52 unsteady state oil water relative permeability curves as the sample, the end point models for irreducible water saturation, residual oil saturation, oil permeability at irreducible water saturation and water permeability at residual oil saturation are established respectively by alternating conditional expectation method. Combining with the reservoir normalized average relative permeability curve, the prediction model of oil water relative permeability is developed. Based on the porosity and air permeability of different regions in the target oil filed, the oil water relative permeability curves of different regions can be obtained by the prediction model. The field result shows that the fitting accuracy of history match, especially the fitting accuracy of the sharply changing section of the water cut, is obviously improved. The prediction model has important guiding significance for the study of the history match and development index prediction of the old oilfield with rich oil-water relative permeability data, and provides a theoretical basis for the gridding of oil water relative permeability curves.