ABSTRACT To address the challenge that silica gel fracturing fluids intrinsically lack effective drag reduction capability, which restricts their application in mid‐ to deep‐reservoir fracturing stimulation, this study proposes a technical strategy that integrates silica gel thickeners with a small dosage of an anionic polyacrylamide drag reducer. Silica gel thickeners with varying SiO 2 concentrations were prepared via the sol–gel method, and a composite fracturing fluid system was constructed by incorporating a low concentration of the drag reducer. A series of systematic experimental investigations were conducted to evaluate the apparent viscosity, shear thinning behavior, viscoelasticity, thixotropy, high‐temperature and shear resistance, and microstructure of the system. The results demonstrate that the composite fracturing fluid system exhibits substantially enhanced macroscopic rheological properties, including apparent viscosity, elastic modulus, and thixotropy, in comparison with the inorganic silica gel thickener alone. Notably, the system maintains a high residual viscosity even after continuous shearing at 180°C for one hour. Microstructural analysis reveals that polyacrylamide molecules function as “adhesive bridges” within the spatially fissured silica gel structure, promoting the aggregation of dispersed gel fragments and maintaining structural connectivity among them. Through electrostatic interactions and hydrogen bonding, the polyacrylamide molecules integrate with the silica gel network, forming a polymer‐bridged three‐dimensional (3D) structure. This synergistic interaction not only enhances the system's viscoelasticity but also markedly improves its resistance to shear‐induced degradation and its ability to recover after mechanical damage. This study elucidates the synergistic enhancement mechanism of inorganic silica gel and organic polymer composite fracturing fluids, providing both theoretical insight and technical support for expanding the application of silica gel fracturing fluids in deep reservoirs.
Xu et al. (Fri,) studied this question.