Nanoslickwater Fracturing Fluid with Enhanced Imbibition Capacity for Low-Permeability Reservoirs

Slickwater (SW) fracturing fluid, renowned for its excellent drag reduction effect in wellbores, is widely used in the hydraulic fracturing process of low-permeability reservoirs. However, the poor imbibition performance of conventional slickwater fracturing fluid constrains the utilization of oil within the matrix pores. Herein, a nanoslickwater fracturing fluid with exceptional imbibition oil recovery capability is constructed by incorporating nano-SiO₂ containing carboxyl and sulfonic acid groups into the conventional slickwater fracturing fluid. The performance of the fracturing fluid, including drag reduction, rheological properties, filtration loss, and formation damage, is systematically evaluated. Finally, the imbibition oil recovery regulation of the system is explained. The prepared nanoslickwater fracturing fluid is a pseudoplastic fluid with a drag reduction rate of 74.53% at 80 °C. The retention rate of drag reduction ability is as high as 96.73% (after shearing for 30 min). The system exhibits excellent filtration reduction properties, resulting in a damage rate to the reservoir of only 7.70%. Core imbibition results indicate that oil produced in the initial rapid imbibition stage accounts for over 65.00% of the entire imbibition process. After the nanoparticles are introduced, the imbibition recovery of nanoslickwater fracturing fluid in the rapid imbibition stage increases significantly. The final imbibition recovery increases from 17.31 to 28.22%. The prepared nanoslickwater fracturing fluid can effectively meet the requirements of slickwater and possesses excellent imbibition oil recovery ability, holding great application potential in the efficient development of low-permeability and tight oil reservoirs.