聚合物强化泡沫体系的性能与岩心流动特征

Performance Evaluation of Polymer Enhanced Foam System and Core Flow Characteristics

刘潇潇 王勃琛 郭程飞

LIU Xiaoxiao WANG Bochen GUO Chengfei

为解决现场泡沫驱出现的气窜问题，通过外加聚合物稳泡剂构建强化泡沫体系，可提高泡沫的稳定性，实现泡沫性能的优化，以提高泡沫驱的应用效果。但强化泡沫体系在提高泡沫稳定性的同时也存在降低发泡性的 问题，需要进一步明确强化泡沫体系的适用条件。为此，开展了聚合物PAAO-1强化泡沫体系性能评价与岩心流 动特征实验研究。结果表明，强化泡沫体系随聚合物PAAO-1浓度增加，泡沫体积减小、泡沫半衰期增大，泡沫综 合指数始终大于无聚合物泡沫体系，确定聚合物PAAO-1使用浓度为1200mg/L。强化泡沫体系平均泡沫直径大 于无聚合物泡沫体系，需较强扰动作用或较高能量引入才能形成细腻、均匀的泡沫。驱替速度较低时，泡沫形成 不充分，强化泡沫体系泡沫有效黏度较小，临界发泡渗流速度为0.12m/d。强化泡沫体系液膜强度高，有效黏度 最高达到435mPa·s，对高渗透层的封堵能力强，不易发生气窜。在均质岩心中，强化泡沫体系提高采收率幅度 为13.67百分点，与无聚合物泡沫体系相当；而在非均质岩心中，强化泡沫体系改变分液率及提高采收率幅度更 高。强化泡沫体系适合渗流速度较大、渗透率范围较广以及非均质严重的油层条件，为现场合理选择泡沫驱油 体系提供依据。

In order to solve the problem of gas channeling in the foam flooding，the enhanced foam system was constructed by adding polymer foam stabilizer to improve the stability of the foam and optimize the foam performance，resulting in improving the application effect of the foam flooding. However，while the enhanced foam system improves the stability of the foam，it also has the problem of reducing the foaming property，so it is necessary to further clarify the applicable conditions of the enhanced foam system. Therefore，the performance evaluation of polymer PAAO-1 enhanced foam system and the experimental study of core flow characteristics were carried out in this paper. The results showed that with the increase of polymer PAAO-1 concentration，the foam volume decreased and the foam half-life time increased，and the foam composite index of the enhanced foam system was always larger than that of the polymer-free foam. The concentration of PAAO-1 was determined to be 1200 mg/L. The average foam diameter of the enhanced foam system was larger than that of the polymer-free foam system，and stronger disturbance or higher energy was needed to form a fine and uniform foam. When the displacement rate was lower，less foam was generated，resulting in lower effective viscosity of the polymer enhanced foam，as a result，the critical foaming seepage velocity was 0.12 m/d. Because of the higher strength of the liquid film of the enhanced foam system，the effective viscosity of the foam reached up to 435 mPa·s，the plugging ability of the high permeability layer was strong，and the gas channeling occur to hardly. In homogeneous cores，the enhanced oil recovery of the polymer enhanced foam was 13.67 percentage point，which was similar to that of polymer-free foam system. In heterogeneous cores，the polymer enhanced foam changed fluid fraction and enhanced oil recovery more dramatically. The polymer enhanced foam is suitable for the reservoir conditions with larger seepage velocity，wider permeability range and more serious heterogeneity，which provides a basis for the reasonable selection of foam flooding system on site.

10.19346/j.cnki.1000-4092.2024.01.017