羧酸盐双子表面活性剂耐温清洁压裂液——以在塔里木盆地致密砂岩气藏应用为例

Temperature-resistance clean fracturing fluid with carboxylate gemini surfactant: A case study of tight sandstone gas reservoirs in the Tarim Basin

为构筑新型低伤害耐温性清洁压裂液,在合成表征系列羧酸盐双子表面活性剂、测试其水溶性的基础上,采用MR301界面流变仪考察了分子结构（疏水链长度及联接基碳数）、浓度、纳米粒子含量对羧酸盐双子表面活性剂增稠清洁压裂液效果的影响,并按行业标准SY/T 5107—2005评价了羧酸盐双子表面活性剂—纳米粒子清洁压裂液性能,用FT—IR和1H—NMR谱图确认了产物为所需的合成结构,水溶性实验确立系列羧酸盐双子表面活性剂溶解温度为34～65℃。黏度测试结果表明：①疏水链碳数越多,羧酸盐双子表面活性剂增稠能力越强,溶液黏度突变升高对应活性剂浓度越小;②疏水链碳数相同,联结基碳数增加,其增稠能力越强,耐温性越好;③ 0.04%纳米ZnO可使3%DC16-4-16溶液高温（100℃）黏度由10 m Pa·s升至30 m Pa·s;④最优羧酸盐双子表面活性剂耐温清洁压裂液配方是3%DC16-4-16＋0.04%纳米ZnO,其具有良好的耐高温剪切稳定性、携砂稳定性及快速破胶性。该清洁压裂液应用于塔里木盆地致密砂岩气藏效果良好。

For the development of a new type of low-damage, temperature-resistance clean fracturing fluid, the MR301 interfacial rhe- ometer was used to investigate how molecular structure （the length of hydrophobic chain and the carbon number of linking group）, con- centration and nanoparticle content influence of the thickening effect of carboxylate Gemini surfactant on clean fracturing fluids, after carboxylate Gemini surfactant was prepared and characterized and its water solubility was tested. The performance of carboxylate Gemini surfactant-nanoparticle Clean fracturing fluid was evaluated according to the industry criteria SY/T 5107-2005. It was confirmed by FT- IR and IH-NMR spectrums that the product is satisfactory in terms of its synthetic structures. Based on water solubility experiments, the solution temperature of carboxylate gemini surfactant is 34-65 ℃ . The following cognitions are obtained by means of viscosity tests. Firstly, the more the carbon numbers of hydrophobic chain, the stronger the thickening capacity of carboxylate gemini surfactant. With the sharp rising of solution viscosity, the concentration of surfactant drops correspondingly. Secondly, when the carbon number of hydro- phobic chain is constant, the thickening capacity and the temperature tolerance get better with the increase of carbon number of linking group. Thirdly, with the introduction of nano-ZnO （0.04%）, the viscosity of DC16-4-16 solution （3%） at high temperature （100℃） can rise from 10 to 30 mPa · s. And fourthly, the optimal temperature-resistance clean fracturing fluid with carboxylate gemini surfactant is composed of 3% DC16-4-16 and 0.04 % nano-ZnO. This product is characterized by such good performances in high-temperature shear resistance, carrier stability and fast breaking property. Good results are realized when this new type of clean fracturing fluid is applied to the tight sandstone gas reservoirs in the Tarim Basin.