In reservoir fracturing with liquid CO2 (LCO2),low viscosity of the fracturing fluid has long been a problem restricting the spread of this new fracturing technology.The phase change ofLCO2 after mixing it with a thickening agent LPE and a micelle enhancer C J-1 has been studied to investigate the thickening mechanisms of LCO2-LPE-CJ-1.HAAKE viscotesters (Model D300/D400) were used to verify the thickening effect of LPE+CJ-1 on the LCO2.Using polarizing microscope,the state of the micelles of the LCO2-LPE-CJ-1 fracturing fluid was studied.The experimental results showed that LPE and C J-1 can thicken the LCO2-LPE-CJ-1 fracturing fluid to about 112 mPa·s,nearly 6 times of the highest viscosity of LCO2(20 mPa· s)that had been reported previously.The thickening mechanismsare that,through ionic complexation between the molecules of LPE and C J-1,the two molecules form rod-shaped micelles,a structure analogous to the 3-D spatial network structure formed by the intertwined molecules of a crosslinked polymer.%液态二氧化碳(LCO2)压裂液黏度低一直是制约新技术推广应用的关键问题.首次利用LCO2与增稠剂LPE和胶束促进剂C J-1混合后LCO2的相态变化,探讨研究LCO2-LPE-CJ-1压裂液的增稠机理,同时借助HAAKE黏度计的D300/400系统验证LPE-CJ-1体系对LCO2增稠效果,利用偏光显微镜对LCO2-LPE-CJ-1压裂液的胶束形态进行验证.实验结果表明:LPE-CJ-1体系可使LCO2-LPE-CJ-1压裂液增黏且最大黏度为112 mPa·s左右,是目前文献报道的LCO2的最大黏度(20 mPa·s)的将近6倍.LCO2-LPE-CJ-1压裂液体系的增稠机理是LPE-CJ-1分子间的离子络合作用后形成的棒状胶束,类似于交联聚合物形成分子间相互缠绕的三维空间网状结构体.
展开▼
