适于低渗透储层的QC-VES清洁压裂液体系实验研究

Experimental study on QC-VES clean fracturing fluid used for ultra-low permeability reservoir

针对陕北"低渗、低压、低温"的储层特点,研制了QC-VES清洁压裂液。首先,以QC-1表面活性剂为主剂、JH-1为反离子助剂、KCl为黏土稳定剂,运用单因素实验法得到了清洁压裂液配方:1.2%QC-1+0.3%JH-1+0.2%KCl。按照SY/T 5107-2005《水基压裂液性能评价方法》和SY/T 6376-2008《压裂液通用技术条件》对QC-VES清洁压裂液体系进行了综合性能评价。结果表明:QC-VES清洁压裂液体系为假塑性非牛顿流体,稠度系数为1.93,流动指数为0.32;具有较好的黏温特性,在80℃、170 s-1剪切速率下连续剪切60 min,黏度仍保持在70 mPa·s左右;具有优良的黏弹性,悬砂性能良好;破胶液黏度为3.42 mPa·s,易返排;残渣接近于零,对于低渗储层岩心伤害率较小,静态平均伤害率为8.59%。

QC-VES clean fracturing fluid was developed for northern Shaanxi ' low-permeability,low-pressure low-temperature' reservoir. Using QC-1 surfactant as based agent,JH-1 and KCl as additives,the optimal formula o QC-VES clean fracturing fluid is determined with single-factor experiments: 1. 2% QC-1 + 0. 3% JH-1 + 0. 2% KCl. The comprehensive performance of QC-VES clean fracturing fluid is evaluated according to SY /T 5107-2005 ' Water-based Fracturing Fluid Performance Evaluation Method' and SY /T6376-2008 ' General Technical Conditions of Fracturing Fluid'. The results show that QC-VES clean fracturing fluid system is a pseudoplastic non-Newtonian fluid,and its consistency coefficient is 1. 93,and flow index is 0. 32; it has good viscosity-temperature characteristics,and its viscosity can remain about 70 mPa·s at least when it is continuously sheared for 60 min at the shear rate of 170 s- 1at 80 ℃; it has excellent viscoelasticity and good sand carrying performance; the viscosity of its gel breaking liquid is 3. 42 mPa·s so that it is easy to flowback; it has no residue,so it has little damage to low-permeability cores,the average static damage rate is 8. 59%.