Development and Performance Evaluation of the High Temperature Resistant Polymer Fluid Loss Agent AAS

With high bottom hole temperatures in deep and ultra deep wells, there are difficulties in mud filtration control. The study on high temperature resistant polymer fluid loss agent was done in which 2-acrylamido-2-methyl propane sulfonic acid (AMPS), acrylamide (AM) and sodium styrene sulfonate (SSS) were used as raw materials and azo diisobutyl amidine hydrochloride as the initiator. The proportion of AMPS, AM and SSS was optimized to obtain terpolymers through chemical reaction. Then the synthetic products were extracted, dried and crushed with acetone to produce ternary copolymerization fluid loss agent, AAS. High-temperature cement slurry filtration performances were evaluated by using infrared spectroscopy, nuclear magnetic resonance hydrogen spectrum characterization, thermogravimetric and differential thermal analysis to determine the stability of these synthetic products. Research results showed that the synthetic copolymer decomposition temperature was 350℃ when the mass ratio of AMPS,AM and SSS was 20:5:1; API cement slurry filtration could be controlled under 150 mL at 180℃ when the dosage of copolymer was increased by 1.6%. At 150℃, the filtration was 56 mL. The research showed that the ternary copolymer fluid loss agent AAS could significantly improve the filtration control ability of the cement slurry at high temperatures. In addition, the ternary copolymer fluid had no obvious effect on rheological properties, strength and thickening time of the cement slurry, so that it could meet the technical requirements for high-temperature cementing slurry.