耐温耐盐两性聚丙烯酰胺稠化剂的制备及其性能

为了提高压裂液稠化剂的耐温耐盐性能，以丙烯酰胺（AM）、丙烯酸（AA）、阴离子单体2-丙烯酰胺-2-甲基丙磺酸（AMPS）和阳离子单体丙烯酰氧乙基三甲基氯化铵（DAC）为单体，单体AM、AA、AMPS、DAC质量比为9∶1∶3∶1.5，将单体以总质量分数为30%溶于水中（水相），将质量分数为10%的乳化剂（Span-80、Tween-80 质量比为9∶1）溶于白油（油相），油水相比为1∶2.5，合成了具有耐温耐盐性的油包水乳液稠化剂PAAD，其黏均相对分子质量为383×10⁴。通过红外光谱和核磁共振氢谱表征了PAAD，测定了聚合物PAAD的耐温性、抗盐性、耐剪切和破胶性能。研究结果表明，PAAD具有良好的耐温抗剪切性能，在90 ℃、剪切速率为170 s^-1下，质量分数为1.5%的PAAD聚合物溶液剪切1.5 h 后黏度保持在51.7 mPa·s。PAAD溶液在高剪切后进入低剪切区后可快速恢复黏度，可保障悬砂不沉降。PAAD具有良好的抗盐性，在矿化度为50 g/L 的模拟高盐海水中，质量分数为1.5%的PAAD聚合物溶液的黏度为45 mPa·s。在90 ℃下，破胶剂用量为0.2%时，质量分数为1.5%的PAAD聚合物溶液在3 h 内可完成破胶，破胶液的表面张力为30 mN/m，油水界面张力为1.9 mN/m，残渣含量为220 mg/L，对岩心基质的伤害性为9%，达到行业标准要求。

Preparation and Properties of Temperature and Salt Resistant Amphoteric Polyacrylamide Thickener

In order to improve the temperature and salt resistance of the fracture fluid thickener，Oil in water emulsion PAAD withtemperature and salt resistance was synthesized using acrylamide（AM），acrylic acid（AA），anionic monomer 2-acrylamide-2-methylpropyl sulfonic acid（AMPS）and cationic monomer acryloxyethyl trimethyl ammonium chloride（DAC）as monomers.The mass ratio of monomer AM，AA，AMPS，DAC was 9∶1∶3∶1.5，and monomers with mass fraction of 30% was dissolved inwater as aqueous phase. Emulsifier Span-80 and Tween-80 with mass ratio of 9∶1 and mass fraction of 10% was dissolved in oil asthe oil phase，and the oil/water ratio was 1∶2.5. The viscosity average molecular weight of PAAD was 383×10⁴ g/mol. The structureof PAAD was characterized by infrared spectroscopy and H-NMR spectroscopy. The properties of the temperature resistance，salt resistance，shear resistance and gel-breaking were investigated. The viscosity of PAAD solution with mass fraction of 1.5%maintained at 51.7 mPa·s after sheared for 1.5 hours at the temperature of 90 ℃，exhibiting good temperature resistance and shearresistance. The viscosity of the PAAD solution could quickly restore when the shear rate entered the low shear region after highshear，which could ensure that the suspended sand does not settle. In the simulated seawater with salinity of 50 g/L，the viscosity ofPAAD solution with mass fraction of 1.5% was 45 mPa·s，indicating that PAAD had good salt resistance. At the temperature of90 ℃，the fluid could be broken within 3 hours at dosage of 0.2% breaker. The surface tension and oil-water interfacial tension ofbroken fluid was 30 and 1.9 mN/m，respectively. The insoluble residuewas 220 mg/L，and the formation damage was 9%. Theseproperties met the requirements the standard in the petroleum industry.