三层油藏水驱后转聚驱的试井解释方法

Well test analysis method for polymer flooding after water flooding in triple-layer reservoir

目前在对于聚合物试井的模型研究中,没有同时考虑多层油藏及非牛顿-牛顿复合油藏2种情况的影响,导致许多海上聚驱油藏实际数据拟合效果不理想。通过考虑海上多层油藏水驱后转聚驱的实际情况,运用数学方法、渗流力学理论,基于严格的数学推导,建立了三层窜流非牛顿-牛顿复合油藏试井解释模型,绘制了井底压力响应特征曲线并对其影响因素进行了讨论,运用实例证明了模型的正确性与实用性。结果表明:三层油藏水驱后转聚驱的试井典型曲线可划分为6个流动段,与一般三层窜流无复合模型的典型曲线特征不同,存在末期复合流段上翘段,聚合物初始浓度对特征曲线影响较小,窜流系数主要影响"凹子"出现的时间,地层系数比和弹性储容比主要影响"凹子"的宽度和深度,复合半径主要影响压力导数曲线上翘段的下移程度。

In the study of the current model of polymer well testing,the two conditions of multi-layer reservoir and non Newton-Newton composite reservoir were not considered simultaneously,which resulted in the fact that the fitting results of actual data of many offshore polymer flooding reservoirs were not ideal.By taking into account the actual situation of polymer flooding after water flooding in multi-layer offshore reservoirs,a well testing model for polymer flooding after water flooding in triple-layer reservoir was established based on the theory of fluid flow in porous media,type curves were plotted and its influencing factors were discussed by the numerical inversion method and this model was verified by the field examples.The result show that the type curves have six regimes,the typical feature which is different from the triple-layer non composite model is the end-stage upwarp segment,the initial concentration of polymer has little influence on the curve,the crossflow coefficient mainly affects the time of the concave,coefficient ratio and storativity ratio mainly affect the width and depth of the concave,and the composite radius mainly affects the down degree of the upper part of the pressure derivative curve.