海水中改性速溶瓜胶的性能与应用

PERFORMANCE AND APPLICATION OF MODIFIED INSTANT GUAR IN SEAWATER

通过特性黏数、激光粒度仪和扫描电镜等手段分析了改性速溶瓜胶(SWF-SRG)的抗盐机理,评价了其抗盐性和速溶性,制备了一套速溶海水基压裂液。实验结果表明:SWF-SRG在海水中其特性黏数基本不变,Huggins参数减小,具有良好的抗盐性;海水中阳离子破坏了分子间羟基形成的氢键,造成SWF-SRG溶液胶团粒径减小,网络结构强度减弱,黏度降低。SWF-SRG在海水中黏度保持率为90.9%,溶胀5 min后黏度达到80%以上,满足海上连续混配压裂需求。现场应用结果表明:以SWF-SRG为稠化剂的速溶海水基压裂液性能满足海上连续混配、大排量、高砂比压裂施工的需求。

The salt resistance mechanism of modified instant guar(SWF-SRG)was analyzed by means of intrinsic viscosity,laser particle size analyzer and scanning electron microscope,and its salt resistance and instant solubility were evaluated,a fracturing fluid based on instant seawater was developed.The experimental results show that the intrinsic viscosity of SWF-SRG in seawater is basically unchanged,and the Huggins parameter is reduced,which performed good salt resistance.The cations in seawater destroy the hydrogen bonds formed by the intermolecular hydroxyl groups,which results in the decrease of,micelle size,the weakening of network structure strength,and the decrease of viscosity of SWF-SRG solution.The viscosity retention rate of SWF-SRG in seawater is 90.9%,and the viscosity reaches more than 80%after swelling for 5 min,which meets the demand of continuous mixing fracturing in offshore.The field application results show that the performance of the fracturing fluid based on instant seawater with SWF-SRG as the thickener meets the requirements of continuous mixing,large pump injection displacement and high proppant concentration fracturing in offshore.