Synthesis and performance evaluation of temperature- and salt-resistant polymer and oil-based suspension thickeners

Le résumé fourni par la source

Traditional fracturing fluid thickeners face challenges, including inadequate thermal stability and pronounced thermal degradation under high-temperature, high-salinity conditions in oil and gas reservoirs, thereby limiting their field application. To address this, a temperature- and salt-resistant copolymer (PAASC) was synthesized from acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and 4-acryloylmorpholine (ACMO). The structure of this PAASC was confirmed by FTIR and 1H NMR. This PAASC was formulated into a rapidly dissolving and stable oil-based suspension. The stability, temperature resistance, salt tolerance, rheological properties, and proppant suspension of PAASC oil-based suspensions were investigated. The PAASC suspension demonstrated excellent two-month stability. The 1.2% PAASC formulation retained 80.5% of its initial viscosity at 120 °C, with a viscous flow activation energy of 4.16 kJ/mol. The 1.5% formulation achieved a viscosity of 75 mPa·s in 8,500 mg/L brine. Overall, PAASC demonstrated superior temperature and salt tolerance compared to the commercial products KCY-50Q and Y22-16. Additionally, the suspension exhibited favorable rheological properties and proppant-carrying capacity. Field application in a coarse sandstone gas reservoir in Shaanxi demonstrated effective proppant transport (maximum sand ratio: 32.5%), stable downhole pressure, and complete breaker efficiency in the flowback fluid. This work provides insights for hydrocarbon recovery in challenging reservoirs.

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