小分子表面活性剂作为牺牲剂降低聚合物吸附损失的研究

Reducing polymer adsorption by using low molecular weight surfactant as sacrificial agent

研究了利用小分子表面活性剂作为牺牲剂来降低聚合物在近井地带吸附量的方法,考察了小分子阳离子CA-1、小分子醇PEG10000和小分子阴离子木质素磺酸钠作为牺牲剂在石英砂上的吸附规律及其对聚合物静态吸附量的影响;利用岩心驱替实验研究了牺牲剂注入方式对聚合物动态吸附滞留量、注入压力及阻力系数的影响。实验结果表明,CA-1、PEG10000及木质素磺酸钠分别可以在50mg·L^(-1)、1 500 mg·L^(-1)、5 000mg·L^(-1)的浓度下使聚合物的静态吸附量分别降低40.5%,36.2%及30.5%。CA-1作为前置段塞注入后能够使聚合物动态吸附量降低30.1%,阻力系数降低了69.7%,能够满足降低聚合物在近井地带吸附滞留量及降低近井地带注入压力的要求,为确保配注量、使聚合物能够进入地层深部发挥驱油效果提供了一种便捷低成本方的方法。

The method of reducing the adsorption of polymer in the near wellbore zone by adding low molecular weight surfactant was studied. The adsorption law of low molecular weight cationic CA-1,alcohol PEG10000 and sodium lignosulphonate on quartzsand and the effect of sacrificial agent on polymer adsorption were studied by static adsorption experiment. The effect of injection methods on polymer dynamics,injection pressure as well as the resistance coefficient were investigated by coreflooding experiments. Experi-mental results proved that 50mg ？ L 1 CA-1^1 500 mg ？ L 1 PEG10000 and 5 000 mg ？ L 1 sodium lignosulfonate were able to re-duce static adsorption of polymer to 40. 5% , 36. 2% and 30. 5% , respectively. The sacrificial agent-cationic surfactant CA-1 was screened, which could reduce the dynamic adsorption of polymer and the resistance coefficient to 30. 1 % and 69. 7% , separately. Result proved that sacrificial CA-1 had the ability to reduce the adsorption quantity and lower injection pressure near the wellbore. The method provided a convenient and low cost method to ensure the injection rate of Bohai oilfield.