Synthesis comparative evaluation of hydrophobic polymer/surfactant fracturing fluids on methane adsorption–desorption and pore structure modifications in coal

Abstract Traditional fracturing fluids often face limitations in achieving a balance between viscosity, gel-breaking capability, and formation protection, which poses a significant challenge for the development of optimally performing fluids in mining applications. This study introduces a novel hydrophobic polymer/surfactant composite (HSC) fracturing fluids synthesized by cross-linking hydrophobically modified hydroxypropyl guar gum (HMHPG) with a gemini-surfactant amide-based bisquaternary ammonium salt (GS-A6). The performance characteristics were evaluated through comparative analysis with conventional fracturing fluids, focusing on viscosity, gel-breaking properties, methane adsorption–desorption behavior, and effects on coal pore structures. The HSC fracturing fluids, comprising 0.2% HMHPG + 0.8% GS-A6, demonstrated superior performance metrics. The viscosity achieved was three times higher than that of the 0.8% GS-A6 fracturing fluids, while the gel-breaking time was reduced by 50% compared to the 0.2% HPG fracturing fluids. The HSC fracturing fluids exhibited reduced impact on methane adsorption and desorption in coal samples, with a 24% lower adsorption damage factor compared to HPG fracturing fluids. Analysis of coal pore structures revealed a decrease in fractal dimension D 1 , indicating surface smoothing effects due to controlled plugging. The developed HSC fracturing fluids demonstrates significant improvements in key performance parameters while minimizing formation damage. These findings provide valuable insights for advancing fracturing fluid technology in mining applications and contribute to the optimization of hydraulic fracturing operations.