低浓度胍胶压裂液有机硼交联剂BOA的合成及其性能评价

Synthesis and Performance Evaluation of Organoboron Crosslinker BOA for Low Concentration Guanidine Fracturing Fluid

针对胍胶压裂液体系胍胶使用浓度偏高、破胶后残渣含量较高的问题,开展低浓度胍胶压裂液体系有机硼交联剂的合成和性能评价研究。以硼酸、正丁醇、乙二醇及二乙烯三胺为原料合成有机硼交联剂并对其反应物加量进行优化,确定出有机硼交联剂BOA合成中反应物的优选质量分数分别为二乙烯三胺34.5%、硼酸14.3%、乙二醇38.7%和正丁醇6.9%。对交联剂进行性能评价,结果表明:有机硼交联剂BOA与0.2%胍胶交联形成的胍胶压裂液的黏度可达84 mPa·s;有机硼交联剂BOA与0.2%胍胶交联形成的胍胶压裂液具有良好的抗温抗剪切性,在100 s^(-1)下逐渐升温至90℃、剪切60 min时及在60℃、100 s^(-1)下剪切90 min时胍胶压裂液的黏度均维持在90 mPa·s,且具有滤失低(滤失系数为2.0×10^(-4)m/min^(1/2))、携砂性能好(悬砂沉降速度为0.045 mm/s)、破胶速度快(在90 min内可完全破胶)、破胶液黏度<5 mPa·s、残渣含量较低(151 mg/L)的优势,可满足压裂液现场施工要求。

In the guanidine gum fracturing fluid system,the concentration of guanidine gum is high and the residual content after gel breaking is high.To address these issues,an organic boron crosslinking agent BOA for low concentration guanidine gum fracturing fluid systems was synthesized using boric acid,n-butanol,ethylene glycol,and diethylenetriamine as raw materials,and the optimal mass fraction of reactants was determined:34.5%for diethylenetriamine,14.3%for boric acid,38.7%for ethylene glycol,and 6.9%for n-butanol.The performance evaluation results of the crosslinking agent show that the viscosity of the guanidine gel fracturing fluid formed by BOA and 0.2%guanidine gel can reach 84 mPa.s,and it has good temperature resistance and shear resistance.The viscosity of the guanidine gum fracturing fluid can be maintained at 90 mPa.s when sheared at 100 s^(-1)for 60 minutes and gradually heated to 90℃,or when sheared at 60℃and 100 s^(-1)for 90 minutes,and it has the advantages of low filtration loss(filtration loss coefficient of 2.0×10^(-4)m/min^(1/2)),good sand-carrying performance(settling speed of suspended sand is 0.045 mm/s),fast gel breaking speed(complete gel breaking within 90 minutes),viscosity of broken fluid<5 mPa.s,and low residue content(151 mg/L),which can meet the on-site construction requirements of fracturing fluid.