Bioinspired by Mussels: Construction of an Ultrasalt-Tolerant, Tunable-Viscosity Slickwater Fracturing Fluid for the...

The extraction of deep coalbed methane (CBM) relies on high-rate, large-volume network fracturing. In water-scarce regions, recycling formation flowback fluids for fracturing fluid preparation is essential to reduce freshwater consumption. To address the performance degradation of fracturing fluids in high-salinity flowback water, a biomimetic salt-tolerant polymer friction reducer (ASD) was developed, inspired by the zwitterionic salt-resistance mechanism in mussels. By integrating hydrophobic association with the antipolyelectrolyte effect, the ASD-based slickwater maintains an apparent viscosity of ∼75 mPa·s in flowback water with total dissolved solids exceeding 120,000 mg/L. Experimental results demonstrate a maximum drag reduction rate of 79.58% and superior dynamic proppant transport. At 60 °C, the fluid completely breaks within 3 h, leaving a low residue of 310 mg/L. Mechanistically, particle size and zeta-potential analyses confirm that ASD exhibits a significant increase in hydrated radius (500-2000 nm) in saline solutions, far exceeding the 10-35 nm observed for conventional hydrolyzed polyacrylamide, validating its strong antipolyelectrolyte response. Molecular dynamics simulations further elucidate this structural adaptability in high salt solutions. This biomimetic strategy offers a high-performance, sustainable solution for deep CBM stimulation using hypersaline flowback water.