注聚井参数优化及合理注采压力梯度研究

摘要

Polymer flooding is an important means to enhance oil recovery, so the selection of polymer injection parameters and building a reasonable pressure gradient are important for the development of polymer flooding. In this paper, choosing injection concentration, injection intensity and production intensity as main factors, the scheme was designed by using the way of permutation and combination. The optimal combination of injection parameters in different period was obtained based on the numerical simulation, and then the best range of parameters was determined, and corresponding adjustment suggestions were put forward. Combined with the optimal results of polymer injection parameters, regression analysis of the recovery efficiency and sweep efficiency changing with the polymer displacement pressure gradient was carried out. The results show that, high concentration and medium injection-production strength should be used in water cut descending stage; moderate concentration and low injection-production strength should be used in low water cut stage; low concentration and high injection-production strength should be used to improve the recovery in water cut increasing stage. Recovery efficiency and sweep efficiency increase with the increase of pressure gradient.%聚合物驱是提高采收率的重要手段，注聚参数的选择和合理聚驱压力梯度的构建对聚合物驱开发效果尤为重要。注入浓度、注入强度和采出强度是影响聚驱开发效果的主要因素，应用排列组合的设计方法进行方案初步设计，根据数值模拟预测结果优选注聚参数组合，分别对含水下降期、含水低值期和含水上升期三个不同聚驱开发阶段的储层合理开发政策界限进行界定和分析，并提出相应的挖潜调整建议。结合注聚参数优化结果，对采收率和聚驱波及系数随聚合物驱替压力梯度的变化规律进行回归分析。研究表明：含水率下降期采取高浓度，中等注采强度注聚；含水低值期中等浓度、低注采强度较为适宜；含水上升期采取低浓度，高注采强度能有效提高采收率；采收率和波及系数随聚驱压力梯度增大呈上升趋势。该项研究对调整聚驱注聚方案指导油田开发具有重要意义。