海上油田非均质性对聚合物驱开发效果的影响

The Impact of Heterogeneity on Polymer Flooding Efficiency in Offshore Oilfield

摘要: 海上某油田平面非均质性较强，基于生产数据分析发现不同注采方式间的聚合物驱效果存在一定的差异，该油藏的非均质性主要表现在油层砂体的渗透率、厚度和几何形态的平面分布上的差异。首先依据油田的平面非均质分布特征构建了三类概念模型，然后通过单因素分析和正交试验设计两种方法建立油藏单元地质模型，针对同一个地质模型，设计了两个对比研究的聚合物驱注采方案，采用油藏数值模拟技术分别建立了18个单因素和18个三因素三水平的多因素油藏数值模拟模型。首先基于单因素模拟计算的累计产油量指标可得出每一类平面非均质条件下最优的注采方式；然后以同一个非均质油藏单元不同聚合物驱注采方案间的累计产油量量差值为分析指标，通过单因素敏感性分析和正交设计直观分析得出了三类平面非均质对聚合物驱开发指标的影响程度，对聚合物驱注采方式的开发指标影响程度最大的是油藏单元砂体厚度平面非均质性，对聚合物驱注采方式的开发指标影响程度第二的是油藏单元砂体渗透率平面非均质性，对聚合物驱注采方式的开发指标影响程度最小的是油藏单元砂体几何形态平面非均质性。

Abstract: The plane heterogeneity was strong in an offshore oilfield, the analysis of oil production data in-dicated that the development effect of polymer flooding pattern was different between different flooding patterns. The plane heterogeneity of the oilfield was induced by thickness, geometry form and permeability of reservoir sand. Firstly, three types of heterogeneity conceptual models were established based on its distributive characteristics. Secondly, 18 geologic models were designed by single factor method and 18 geologic models were designed by orthogonal design method. For the same geologic model, two different polymer flooding patterns were proposed. Then by applying reservoir numerical simulation method, 36 reservoir numerical simulation models were established. By taking the cumulative oil production as research objectives, optimum polymer flooding pattern was proposed firstly by applying single factor sensitivity analysis. Then by analyzing the difference of cumulative oil production of different flooding patterns for the same geology model, it can be concluded that there has strong influence on polymer flooding efficiency of plane heterogeneity. And by applying single factor sensitivity analysis and intuitive analysis, the effect level of three types of plane heterogeneities is obtained. And the heterogeneity of thickness is ranked the first, permeability is the second, geometry form is the third.