Influence of Fracturing Fluid Properties on the Frictional Coefficient of Shale Rock and Hydraulic Fracture Length

This study investigated the micro-sliding frictional behavior of shale in fracturing fluids under varying operational conditions using Chang 7 shale oil reservoir core samples. Through systematic micro-sliding friction experiments, the characteristics and governing mechanisms of shale friction were elucidated. Complementary analyses were conducted to characterize the mineral composition, petrophysical properties, and micromorphology of the shale samples, providing insights into the relationship between microscopic structure and frictional response. In this paper, the characteristics and variation law of shale micro-sliding friction under different types of graphite materials as additives in LGF-80 (Low-damage Guar Fluid) oil flooding recoverable fracturing fluid system were mainly studied. In addition, the finite element numerical simulation experiment of hydraulic fracturing was adopted to study the influence of the friction coefficient of natural fracture surfaces on fracture propagation and formation of the fracture network. The geometric complexity of fracture networks was systematically quantified under varying frictional coefficients of natural fracture surfaces through multi-parametric characterization and morphometric analysis. The research results show that graphite micro-particles reduce friction and drag. Based on this, this paper proposes a new idea of graphite micro-particles as an additive in the LGF-80 oil flooding recoverable fracturing fluid system to reduce friction on the fracture surface.