Comparative Thermo–Hydro–Mechanical Analysis of Hydraulic and Supercritical CO2 Fracturing for Enhanced Reservoir Permeability: A Mini-Review

Abstract

Abstract Hydraulic fracturing (HF) and supercritical carbon dioxide (SC-CO2) fracturing are essential technologies for enhancing reservoir permeability in unconventional energy production. Determining the optimal fracturing strategy for specific reservoir conditions is a technically demanding challenge. This study conducted a thermo–hydro–mechanical (THM) coupled analysis to evaluate the mechanisms and effectiveness of HF and SC-CO2 fracturing, with emphasis on the temperature distributions, fluid dynamics, and stress fields generated. The findings indicate that SC-CO2 fracturing can generate more complex fracture networks, with breakdown pressures that are 30%–50% lower than those of HF. This is attributed to its ultralow viscosity, near-zero surface tension, and high diffusivity. Thermal effects can induce additional thermal stress, thereby increasing fracture complexity. Field studies have demonstrated that SC-CO2 fracturing can enhance production by 20%–300% compared with HF, while simultaneously reducing water consumption and promoting CO2 sequestration. Nevertheless, several challenges remain, including insufficient proppant transport efficiency, poor material compatibility, and the phase stability requirements of shallow reservoirs. This study highlights the potential of SC-CO2 fracturing as a viable alternative to HF while identifying critical gaps in field-scale implementation, thus providing a foundation for optimizing fracturing techniques across diverse geological settings.