阳离子表面活性剂的碳链长度对缓速性能影响

Effect of Carbon Chain Lengths of Cationic Surfactant on Retarded Performance

申 鑫 王世彬 张永春 陈付虎 郭建春

SHEN Xin WANG Shibin ZHANG Yongchun CHEN Fuhu GUO Jianchun

阳离子表面活性剂能改变岩石表面性能，从而降低酸岩反应速率，保证酸液往地层深部推进。为了揭示阳离子表面活性剂的碳链长度对缓速性能的影响，本文利用表面张力仪、电导率仪测定了 4种长碳链阳离子表面活性剂即十四烷基三甲基氯化铵、十六烷基三甲基氯化铵、十八烷基三甲基氯化铵、二十二烷基三甲基氯化铵（记作 CnTAC，n=14、16、18、22）的临界胶束浓度 ccmc，利用原子力显微镜观测 CnTAC在岩石表面的吸附形态，采用固/液/气三相接触角法研究了阳离子表面活性剂改变方解石表面润湿性的能力，并测试了静态酸岩反应速率。研究结果表明，随着碳链长度增大，CnTAC的 ccmc明显减小；CnTAC在方解石表面吸附形态以单层吸附为主，CnTAC可将亲水固体表面润湿反转为亲油性，随着碳链长度增大，CnTAC处理过的方解石的吸附层厚度变小，亲油性增强。CnTAC可有效降低酸岩反应速率，碳链长度为 14的 C14TAC对酸岩反应的缓速性能最好，缓速率为 69.70%，随着碳链长度的增大，CnTAC的缓速性能变差，方解石刻蚀表面形态由不均匀而趋于均匀。图 20表 3参 13

Cationic surfactants can change the surface properties of rocks and could be used to reduce the rate of acid-rock reaction to ensure that the acid was pushed deeply into the reservoir. In order to reveal the effect of the carbon chain length of the cationic surfactant on the retarding performance，in this paper，the critical micelle concentrations of tetradecyltrimethyl ammonium chloride，hexadecyltrimethyl ammonium chloride，octadecyltrimethyl ammonium chloride and dodecyltrimethyl ammonium chloride（CnTAC，n=14，16，18，22）were determined by surface tensiometer and conductivity meter. Atomic force microscope was used to observe the adsorption patterns of CnTAC on the rock surface. The solid/gas/liquid three-phase contact angle method was used to study the ability of CnTAC changing the surface wettability of calcite. Finally，the static acid-rock reaction rate was tested. The experimental results showed that with the increase of the carbon chain length，the ccmc of the CnTAC decreased obviously，the adsorption of CnTAC on calcite surface was mainly monolayer adsorption；CnTAC could reversed wettability of hydrophilic solid surface to lipophilicity，with the increase of carbon chain length，the thickness of adsorbed layer of calcite treated by CnTAC decreased and the hydrophobicity of calcite increased. CnTAC could effectively reduce the acid rock reaction rate and the C14TAC had the best retarding properties，the retardance rate was 69.70%，with the increase of carbon chain length，the retardation performance of CnTAC became worse，and the surface morphology of calcite etching tended to be inhomogeneous.