Abstract:

In order to develop the heat-resistant hydrophobic polymer fracturing fluid system, in this paper, hydrophobic monomer octadecyl methacrylate was introduced into acrylamide acrylic acid AMPS to improve the temperature resistance of thickeners, and the polymer thickeners PAS was synthesized. The experimental results showed that the preparation conditions of modified polymer were as follows: monomer accounted for 30% of the total mass, emulsifier accounted for 10% of the oil phase, hydrophilic lipophilic balance (HLB) was 6, initiator accounted for 0.2% of the total mass of monomer, and oil water ratio was 1∶2. Its viscosity-average molecular weight was 450×10⁴g/mol. The viscosity of the polymer at 1.5% concentration remained at 80mPa·s after shearing for 1.5h at 120℃ and 170s^-1. The polymer had good temperature resistance and shear recovery performance. Its particle size distribution was 500—1200nm. When the amount of potassium persulfate as gel breaker was 0.03%, the viscosity could be reduced to 5mPa·s at 90℃, reaching glue breaking.

Key words: fracturing fluid, temperature resistance, thickener, shear resistance, gel-breaking property

摘要：

为发展耐温疏水聚合物压裂液体系，本文在丙烯酰胺、丙烯酸、2-丙烯酰胺-2-甲基丙磺酸（AMPS）中引入了疏水单体甲基丙烯酸十八烷基酯来提高稠化剂的耐温性，合成了聚合物稠化剂PAS。实验结果表明，制备改性聚合物的条件为：单体占总质量的30%，乳化剂占油相的10%，亲水亲油平衡值（HLB）为6，引发剂占单体质量的0.2%，油水相比为1∶2。其黏均分子量为450×10⁴g/mol。测试了该聚合物1.5%的浓度在120℃、170s^-1下剪切1.5h后黏度保持在80mPa·s，具有较好的耐温性，并具有剪切回复性能；其粒径分布为500~1200nm；在破胶剂过硫酸钾的用量为0.03%时，在90℃下，其黏度可以下降到5mPa·s，完成破胶。

关键词: 压裂液, 耐温性, 稠化剂, 耐剪切性, 破胶性