边水油藏聚合物驱风险分析

Polymer flooding Risk Assessment in edge-aquifer reservoir

聚合物性能及地质、油藏差异对驱油效果影响明显,一般以定性描述为主;针对此现状,开展了影响聚合物驱效果的因素定量研究。首先运用正交设计与数值模拟方法,建立了影响聚合物驱效果的8项因素与提高采收率幅度间函数模型,然后运用Monte Carlo方法进行预测。研究得出了8项因素的权重分布,并计算出提高采收率幅度与概率分布情况。结果表明,影响提高采收率幅度最大的因素为聚合物黏度保留率,其次为矿化度,影响最小的为剪切程度。提高采收率幅度与发生概率分布为:提高采收率5.68%的概率为90%;提高采收率7.07%的概率为50%;提高采收率8.45%的概率为10%。最后,应用数值模拟方法对预测结果进行检验,误差小于5%,说明该风险分析方法稳定、可靠,达到了为聚合物驱油风险分析提供定量预测的目的。

Polymer flooding performance is significantly dependent on polymer performance,geology and reservoir properties and qualitative assessment is generally used in risk assessment. A quantitative study is carries out on polymer flooding performance.Firstly,orthogonal design and numerical simulation are used to establish the function between 8 factors that directly relate to polymer flooding performance and EOR increment. Monte Carlo method is used to predict the weight distribution of 8 factors and determine EOR increments and their probability distributions. Result illustrates that the EOR increment is mostly dependent on polymer viscosity retention ratio,followed by salinity,and is least dependent on shear. The EOR increments and probability distributions are: the probability of 5. 68% EOR increment is 90%,the probability of 7. 07% EOR increment is 50% and the probability of 8. 45% EOR increment is 10%. Finally,numerical simulation is applied to test the prediction and the corresponding prediction error is less than5%. This stable and reliable method can be used in the qualitative risk assessment of polymer flooding.