表面活性剂对鄂尔多斯盆地致密砂岩储层渗吸采收率影响分析

Effect of Surfactants on Imbibition Recovery of Tight Sandstone Reservoirs in Ordos Basin

史伟奇 程宇雄 吴彬 严亮 葛一卓 陈明贵

SHIWeiqi CHEN Yuxiong WU Bin YAN Liang GE Yizhuo CHEN Minggui

为了研究致密砂岩储层表面活性剂的渗吸作用机理，首先研究了4 种不同类型的表面活性剂润湿性反转能 力与降低界面张力能力，并开展了表面活性剂渗吸实验；结合核磁共振测试与高压压汞实验表征了岩心微观孔 隙特征，并在渗吸过程中进行核磁共振测试，研究了不同岩心孔隙类型的渗吸作用机理。研究表明：阴离子表面 活性剂润湿性反转与降低界面张力的能力更强，且润湿性改变是提高渗吸采收率的关键。致密砂岩孔隙类型为 纳米孔（r ＜ 0.1 μm）、微孔（0.1 μm ＜ r ＜ 10 μm）、宏孔（r ＞ 10 μm），其中微孔为原油主要储存空间，孔隙体积 占比达67.7%；宏孔的渗吸采收率最大，其次为微孔、纳米孔。阳离子活性剂CTAB、两性离子表面活性剂BS-12 对渗吸具有抑制作用，非离子表面活性剂APG-12 的渗吸效果同样较差；阴离子表面活性剂SDS、AES润湿性改 变效果最好。对于致密岩石亲水润湿的质量分数为0.1%表面活性剂溶液，润湿时间（AES＜ SDS ＜ APG-12）越 短，致密岩石微纳米孔喉表面吸附的表面活性剂的数量越多，润湿性转变越强，表面活性剂渗吸采收率 （APG-12＜ SDS ＜AES）越高。

In order to study the mechanism of percolation effect of surfactants in dense sandstone reservoirs，four different types of surfactants were tested for wettability and interfacial tension，and surfactant percolation experiments were carried out. The microscopic pore characteristics of cores were characterized by combining nuclear magnetic resonance （NMR） tests and high-pressure mercury compression experiments，and NMR tests were conducted during percolation to study the mechanism of percolation effect of different pore types. The results showed that the anionic surfactant had a stronger ability to change the wettability and reduce the interfacial tension，and the change of wettability was the key to improve the recovery rate of percolation. The pore types of dense sandstone were classified as nanopore（r ＜ 0.1 μm），micropore（0.1 μm ＜ r ＜ 10 μm），and macropore （r ＞ 10 μm），among which micropore was the main storage space of crude oil，with 67.7% of the pore volume. The recovery rate of percolation was the largest for macropore，followed by micropore and nanopore. The cationic surfactants CTAB and amphoteric surfactants BS-12 had inhibitory effect on percolation，and non-ionic surfactants APG-12 had the similar poor percolation effect， while anionic surfactants SDS and AES had the best wettability change effect. For surfactants solution，mass fraction being of 0.1%，with hydrophilic wetting of dense rocks，the shorter the wetting time（AES ＜ SDS ＜ APG-12），the greater the number of surfactants adsorbed on the surface of micro- and nano-pore throats of dense rocks，the stronger the wettability change，and the higher the surfactant percolation recovery（APG-12＜ SDS ＜AES）.

10.19346/j.cnki.1000-4092.2023.01.018