Salt-tolerant and instant friction reducer for slickwater fracturing stimulation based on dispersion polymerization

In this study, a salt-tolerant friction reducer was proposed on the basis of dispersion polymerization to recycle high-salinity produced water. A dispersion polymerization friction reducer (DPFR) was synthesized using an acrylamide copolymer in an ultra-high-salinity solution, and its friction reduction performance was simulated in produced water. The gel permeation chromatography revealed that DPFR exhibited high molecular weight and low dispersity could stretch rapidly and show hydration in 2 s. Thus, the proposed reducer exhibits considerable potential for fracturing friction reduction. These performance tests were primarily conducted using a closed-loop flow system at various bulk velocities, dosages, and salt contents; therefore, the experimental results revealed that 2000 ppm DPFR exhibited the maximum slickwater friction reduction efficiency (FRe) of approximately 80% at 40 L/min. Furthermore, DPFR retained a high friction reduction performance of more than 75% at concentration of 120 g /L Na+, 100 g/L Ca2+, 20 g/L Fe3+, 180 g/L Cl−, and 100 g/L SO42- solutions. Functional tests revealed that novel DPFR exhibited a high salt tolerance in various high-salinity produced waters. Furthermore, DPFR is economical, environment-friendly and operationally efficient, because no additional organic additive is required in the synthesis and application process.