油酸酰胺丙基二甲基叔胺改性羟丙基胍胶耐高温压裂液的交联流变性能

Cross-linking Rheological Properties of Oleic Acid Amidopropyl Dimethyl Tertiary Amine Modified Hydroxypropyl Guar Gum Fracturing Fluid

为获得耐高温压裂液增稠剂新体系,采用油酸酰胺丙基二甲基叔胺疏水改性羟丙基胍胶(HPG),获得一种新型疏水改性耐高温耐剪切稠化剂(O-HPG)。利用红外光谱FTIR、低核磁共振LF-NMR、热重TGA等分析方法表征结构。利用4-参数振荡剪切交联流变动力学方程描述交联过程。进一步研究O-HPG与HPG溶液与有机锆交联剂交联形成凝胶的耐高温性耐剪切性能。研究表明,4-参数振荡剪切交联流变动力学方程可以很好拟合交联过程并得到最佳交联条件;向质量分数0.6%O-HPG基液中加入0.25%体积比的有机锆交联剂FAC-201(锆离子含量为0.5%),在pH 10.8下交联形成高黏弹凝胶,弹性模量达到178.8 Pa,比相同条件下HPG体系的(58.3 Pa)增加了2倍;O-HPG压裂液在200℃、剪切速率100 s^(-1)的条件下剪切1.5 h后保留黏度大于80 mPa·s,可满足高温压裂液黏度要求(大于50 m Pa·s),获得耐温200℃的压裂液体系。改性后O-HPG耐高温耐剪切性能较HPG有显著提高且O-HPG压裂液更易破胶。图9表4参15。

In order to obtain a high temperature resistant fracturing fluid thickener,hydroxypropyl guar gum(HPG)was modified with(Z)-9-octadecenoic acid amide(oleic acid amide).The structure was characterized by FTIR,LF-NMR,TGA.the cross-linking process was fitted by 4-parameter oscillatory shear cross-linking rheological kinetic equation.Furthermore,the high temperature and shear resistance performance of the gels of O-HPG and HPG was studied.The results showed the equation could fit the process well and obtain the best cross-linking conditions.The G'max of the O-HPG gel,formed through adding 0.25%(volume ratio)zirconium organic crosslinker into 0.6%O-HPG solution at pH 10.8,was 178.8 Pa,which was three time of that of HPG gel formed at the same condition,being of 58.3 Pa;the residue viscosity of O-HPG gel was about 80 mPa·s after sheared for 1.5 hours at the temperature of 200℃and the shear rate of 100 s-1,satisfying the demands of viscosity(more than 50 mPa·s for 60 min)for high temperature fracturing fluids.Compared with the HPG gel,the O-HPG gel had better temperature-tolerate and shear-tolerate properties,could be broken more easily.This work provides a rheological basis and a new thickener for ultra-high temperature fracturing fluids.