页岩气压裂返排液中表面活性剂对处理剂配方的影响

Influence of the surfactant in the fracturing flow-back fluid of shale gas on the formula of treating chemical

张裕良 罗凯 刘源 王天阁 周洪涛

ZHANG Yuliang LUO Kai LIU Yuan WANG Tian’ge ZHOU Hongtao

中国石油大学(华东)石油工程学院 中国石油大学(华东)教育部非常规油气田开发重点实验室 中国石油天然气股份有限公司浙江油田分公司西南采气厂

School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, Shandong, China MOE Key Laboratory of Unconventional Oil and Gas Field Development, China University of Petroleum (East China)，Qingdao 266580, Shandong, China Southwest Gas Production Plant, PetroChina Zhejiang Oilfield Company, Yibin 645250, Sichuan, China

页岩气开发后期常采用泡排工艺，其产生的泡排废水与压裂返排液混合后，引入的表面活性剂会大大增加水体处理难度，现有水处理工艺无法满足现场需求，为降低压裂返排液处理难度，有必要从源头重新寻找解决办法。从处理剂PAC的角度重新研究了泡排用表面活性剂的选择，以川南压裂返排液为研究对象，考察了4类表面活性剂对处理剂PAC的影响，同时测定悬浮物Zeta电位以研究影响规律，接着进行了起泡性评价，最终优选出对絮凝影响较小且起泡性良好的表面活性剂。现场应用结果表明，表面活性剂对PAC影响的顺序为阴离子型>非离子型>两性离子型≈阳离子型，十二烷基乙氧基磺基甜菜碱为最佳表面活性剂。现场泡排工艺采用后，满足泡排要求的同时可使下游压裂返排液处理剂PAC日均浓度从400~600 mg/L降低至300~400 mg/L，应用效果良好且具有进一步推广应用的价值。

Foam drainage technology is often adopted in the late stage of shale gas development. After its produced foam drainage wastewater is mixed with fracturing flow-back fluid, the introduced surfactant increases the water treatment difficulty greatly. In this situation, the field demand cannot be satisfied if only water treatment technology is optimized. In order to decrease the fracturing flow-back fluid treating difficulty, it is necessary to search for a solution again from the very beginning. The selection of surfactant for foam drainage was studied from the perspective of the treating chemical PAC. The fracturing flow-back fluid in the southern Sichuan Basin was taken as the research objet to investigate the influences of four kinds of surfactants on the treating chemical PAC while measuring Zeta potential of suspended materials to understand the influence mechanisms. Then, the foamability was evaluated. Finally, the surfactant with less influence on flocculation and good foamability was selected out and applied on site. It is indicated that the influence of surfactant on PAC is ranked as anionic surfactant>nonionic surfactant>zwitterionic surfactant≈cationic surfactant, and dodecyle ethoxy sulfobetaine (DESB) is the optimal surfactant. After the foam drainage technology is applied on site, the average daily concentration of downstream fracturing flow-back fluid treating chemical PAC is reduced from 400-600 mg/L to 300-400 mg/L while the foam drainage demand is satisfied. Obviously, the application effect is good and worth popularizing.

10.13639/j.odpt.2020.03.015