酸性清洁压裂液体系性能研究及现场应用

Performance Research and Field Application of Acidic Viscoelastic Fracturing Liquid

为了适应CO_2泡沫压裂施工要求,通过芥酸酰胺丙基-N,N-二甲基叔胺盐胶束与高分子量聚氧化乙烯(PEO)共混,制得一种耐酸性表面活性剂/聚合物清洁压裂液;并对压裂液的相关性能进行了系统评价。实验结果表明:在80℃、90 min剪切作用后,压裂液黏度依然维持90 m Pa·s左右;储能模量G'为7 Pa,耗能模量G″为1 Pa,压裂液具有较好的黏弹性;压裂液在矿化度1 000~8 000 mg·L^(-1)均可满足悬砂要求;破胶液黏度低于5m Pa·s,残渣含量为50 mg·L^(-1),破胶液表面张力为23.88 m N·m^(-1),界面张力为0.024 6 mN·m^(-1),破胶残渣粒径平均值为40 nm;岩心伤害率在11%以下,压裂液对支撑剂短期导流能力的伤害率在15%以下,可满足压裂施工要求。现场试验结果表明:该压裂液携砂性能好,泡沫质量高,增产效果明显,适合CO_2泡沫压裂施工。

In order to meet the requirements for CO_2 foam fracturing construction,an acid surfactant/polymer acid clean fracturing fluid was prepared by blending the erucic acid amide propyl-N,N-dimethyl tertiary amine salt micelles with high molecular weight polyethylene oxide（ PEO）,and the corresponding properties of. fracturing fluid were systematically estimated. The experimental results showed that fracturing fluid viscosity remained 90 m Pa·s after shearing action in 80 ℃,90 min. Storage modulus G＇ was 7 Pa,loss modulus G″ was 1 Pa. The fracturing fluid can meet the requirements of suspended sand in 1 000 ~ 8 000 mg·L^（-1）of mineralization. Gel breaking liquid viscosity was lower than 5 m Pa·s,residue content was 50 mg·L^（-1）,surface tension of gel breaking liquid was23. 88 m N·m^（-1）,the interfacial tension was 0. 024 6 m N·m^（-1）,average particle size of gel breaking residue was 40 nm; the core damage rate was below 11%,short-term flow conductivity damage rate of propping agent was below 15%,this can meet the requirements of fracturing construction. Field test results showed that the fracturing fluid had good proppant-carrying capacity,high foam quality and obvious stimulation effect,suitable for CO_2 foam fracturing construction