基于含水变化规律的聚合物驱注入参数优化

目前聚合物驱调整措施和参数优化的具体研究方法中，很少有针对单井注聚效果开展的研究，缺乏可借鉴的技术经验。将聚驱含水变化曲线划分为4个阶段，分别为未见效期、含水下降期、持续见效期和含水回返期；同时利用见效时间、含水降低幅度和见效有效期3个参数，定量表征含水规律。通过综合数值模拟和数理统计学方法找到不同含水阶段的主控因素，并且基于多元回归方法，得到主控因素与含水定量表征参数的数学模型，从而建立了不同含水阶段聚合物注入参数的优化决策模型。研究结果表明，未见效期，要以建立阻力系数为核心，开展均衡注采措施；含水下降期，要以提高注入速度为核心，开展引效促效措施；持续见效期和含水回返期，要以改变聚合物浓度为核心，开展差异化注入。渤海SZ油田根据每口油井含水所处的阶段，实施“一井一策”，2019年实施了10井次聚驱参数优化，累增油2.4×104 m3。

Optimizing the injection parameters of polymer flooding based on the change laws of water cut

At present, the methods specifically researching adjustment measures and parameter optimization of polymer flooding rarely study the single-well polymer flooding effect and there are no available technologies and experience as reference. The water cut curve of polymer flooding was divided into four stages, including non-response stage, water-cut decline stage, continuous response stage and water-cut return stage. In the meantime, water-cut laws were quantitatively characterized by using three parameters, e.g. response time, water-cut decline amplitude and effective response stage. Then, main control factors in different water-cut stages were determined by means of comprehensive numerical simulation and mathematical statistics, and the mathematical model of the parameters for quantitatively characterizing main control factors and water cut was established on the basis of multi-variant regression method. Finally, the optimized decision making model for the polymer injection parameters of different water-cut stages was established. And it is indicated that in the non-response stage, balanced injection-production measures shall be taken with the construction of resistance coefficient as the core. In the water-cut decline stage, effect induction and promotion measures shall be taken with the increase of injection rate as the core. In the continuous response stage and the water-cut return stage, differential injection shall be implemented with the change of polymer concentration as the core. In SZ Oilfield of Bohai Sea, one strategy for one well is conducted based on the water-cut stage of each well. In 2019, polymer flooding parameter optimization was carried out ten well times, which provides the cumulative oil increment of 2.4×104 m3.