三元复合驱聚合物/表活剂滞留损耗研究

Study on the Retention Loss of Polymer/Surfactant for ASP Flooding

目前油田处于高含水期,三元复合驱技术日渐成熟。三元复合驱在挖潜剩余油过程中,地层砂岩对聚合物和表活剂存在滞留损耗作用;随着复配体系溶液向生产井运移,溶液中聚合物、表活剂的含量逐渐降低,这将影响孔隙中残余油的洗油效率。通过室内试验和数值模拟研究砂岩对聚合物和表活剂滞留损耗规律,并分析不同渗透率情况下砂岩对聚/表二元体系滞留损耗大小,实验结果表明:聚/表二元体系溶液中药剂浓度与运移距离成指数递减关系;砂岩对聚合物、表活剂的滞留损耗量均与渗透率成反比关系;由于聚合物分子链远大于表活剂,对于小孔隙表活剂更容易被吸附,因而砂岩对表活剂的滞留损耗强于聚合物,且渗透率越低越明显。

At present, most oilfields are in the high water cut stage, and the ASP flooding technology becomes more and more mature. In the process of ASP flooding to produce remaining oil, the sandstone can cause the retention loss of polymer and surfactant. As the compound system solution transports to the production well, the content of polymer and surfactant in the solution gradually decreases, which will affect the sweep efficiency of residual oil in the pores. In this paper, the retention loss of polymer and surfactant on the sandstone was studied through indoor experiment and numerical simulation, and the levels of retention loss under different permeability were analyzed. The experimental results showed that： the concentration of polymer/surfactant in the composite solution had exponential decline relation with the migration distance; the retention loss of polymer and surfactant on the sandstone was inversely proportional to the permeability; because the polymer molecular chain was much larger than that of surfactant, for small pores, the surfactant was more easily absorbed by the sandstone, so surfactant retention loss was higher than the polymer, and the lower the permeability, the more obvious the phenomenon.