复合表面活性剂提高低渗透油田采收率研究

本文将自制羧基甜菜碱与烷醇酰胺表面活性剂按质量比1:1混合，得到复配表面活性剂体系。研究了该复配体系的界面活性及抗吸附性，监测了油滴的三相接触角随时间变化，并进行了模拟驱油实验。结果表明，复配表面活性剂体系与临盘原油的界面张力值可以达到10-3mN/m的超低数量级，经过石英砂静态吸附后，该复配体系依具有较低界面张力性能，并且该体系对原油有良好的乳化性能。油滴的三相接触角监测结果表明，复配表面活性剂能使固相表面由亲水性向偏亲油性转变，从而降低了油滴在低渗孔隙中的贾敏效应，提高了注水开发效果。在现场弱碱性水驱的基础上，注入1.5 PV的质量分数为0.5%表面活性剂复配体系段塞后，采收率进一步提高13%，注水压力下降。该复配表面活性剂在低渗透油田注水开发过程中有着一定的应用价值。

Studies on Surfactant Enhanced Oil Recovery for Low Permeability Oilfield

A compound surfactant system of carboxybetaine/alkylamide at mass ratio of 1:1 was achieved, and then the interfacial activity, adsorption resistance and the alteration of three-phase contact angle were studied, besides, flooding experiments were conducted. The results showed that the system could reduce interfacial tension between water and Linpan crude oil to 10-3 mN/m magnitude. After the static adsorption of the quartz sand, the surfactant system still had the lower interfacial tension and good emulsification property. With monitoring three-phase contact angle, the surfactant system made the surface of the core change form hydrophilic to lipophilic, which could reduce the Jamin effect of oil droplets in the low permeability pore and improve the development?result of water injection. Based on weak alkaline water flooding in the field, the oil recovery further was increased by 13% after injecting 1.5 PV surfactant system slug with mass fraction of 0.5%, and the injection pressure dropped. This surfactant system had a certain application value in low permeability oilfield.