微泡沫酸性清洁压裂液的制备及性能

合成一种非离子表面活性剂脂肪酰胺丙基-N,N-二甲基叔胺(SCF-18)作为增稠剂,以NaHCO3为起泡剂,在酸性条件下交联,制得一种微泡沫酸性清洁压裂液。对该体系的性能进行了室内评价,结果表明,质量分数分别为3%SCF-18+0.5%缓蚀剂ATMP+3.6%NH4Cl+1%冰乙酸+0.5%NaHCO3,90℃、170 s-1剪切60min,压裂液的黏度为75 mPa.s,具有较好的耐温耐剪切性;在温度低于70℃时,储能模量远大于耗能模量,黏弹性良好;90℃体系的砂降速度为0.766 1 mm/s,具有很强的携砂能力;加入质量分数5%的原油,40 min即可破胶,破胶液黏度为2.84 mPa.s。通过化学反应形成的CO2微泡沫可以有效地降低压裂液的滤失量,同时可以提高返排率,降低对底层的伤害,改善压裂效果。

Study on Properties of Microfoam Acid Clean Fracturing Fluid

A microfoam clean fracturing fluid was obtained under the acidizing fluid system by using non-ionic surfactant(SCF-18) as thickner and NaHCO3 as foam agent.The property of the system was studied.The results show that the optimum formula of acid clean fracturing fluid was 3% SCF-18 + 0.5% corrosion inhibitor ATMP +3.6% ammonium chloride + 1% glacial acetic acid + 0.5% NaHCO3.The microfoam acid clean fracturing fluid system had better temperature resistance and shear resistance performance under the conditions of 90 ℃ and 170 s-1.The storage shear modulus G′ was higher than loss shear modulus G″ when the temperature was below 70 ℃,which indicates that the fracturing fluid has high viscoelasticity.The sedimentation rates of the seeds at 90 ℃ in the fracturing fluid was 0.766 1 mm/s which indicate that the fracturing fluid has a better sand-carrying performance.The viscosity of the microfoam clean fracturing fluid decreased to 2.84 mPa·s during 40 min when the dosage of kerosene was of 5%.With the crosslinking reaction,the CO2 microfoam can apparently reduce the amount of filtration and the damage to the form and improve the flowback rate.It can be concluded that the effect of the microfoam acid clean fracturing fluid system is improved.