Abstract:In order to meet the needs of high temperature reservoir fracturing, a hydrophobically associating polymer ( AAOS ) was synthesized by acrylamide ( AM ), acrylic acid ( AA ), octadecyl dimethyl allyl ammonium chloride ( ODAAC ) and octadecyl methacrylate ( SMA ), then, a new “self-crosslinking” high temperature resistant water-based liquid thickener ( FPM-1 ) was developed by using low molecular alcohol (ethylene glycol, glycerol, n-propanol), surfactant (coconut diethanol amide and lauryl sodium sulfate) and AAOS. SEM analysis showed that the mass fraction of 0.30 % FPM-1 aqueous solution could significantly increase the hydrophobic association crosslinking between AAOS polymer molecules and increase the hydrodynamic volume of the polymer. The solubility, apparent viscosity, salt tolerance and rheological properties of FPM-1 were tested. The results showed that FPM-1 solution was a high viscoelastic fluid with good sand suspension performance. The dissolution time of the mass fraction of 0.27 % AAOS was 7 min in water and the final viscosity was 90 mPa · s. The dissolution time of the mass fraction of 0.60 % FPM-1 with the same effective polymer content was only 3 min in water and the final viscosity was 165 mPa · s, indicating that the FPM-1 system could significantly improve the viscosity and dissolution rate of the polymer. After shearing at 90 °C, 170 s-1 for 1 h, the viscosity of the mass fraction of 0.27 % AAOS aqueous solution was 51 mPa · s, the viscosity of the mass fraction of 0.60 % FPM-1 aqueous solution was 77 mPa · s, and the viscosity of the mass fraction of 1.40 % FPM-1 aqueous solution was 53 mPa · s after shearing at 180 °C, 170 s-1 for 1 h. The viscosity retention rate of the mass fraction of 0.60 % FPM-1 in 5 × 104 mg / L salinity brine was 60 %. FPM-1 solution has excellent salt resistance, high temperature resistance and shear resistance. The surface/interfacial tension test showed that the FPM-1 system had low surface/interfacial tension, which was conducive to the flowback and recycling of the fracturing fluid breaking liquid.