Abstract
With the surge in hydrocarbon demand and the depletion of traditional resources, unconventional reservoirs such as shale, tight gas, and coal have become important energy sources. Conventional hydraulic fracturing methods, while effective, are often water-based, environmentally unfriendly, and can damage the formation. Fracturing techniques based on carbon dioxide (CO 2 ) show great promise as waterless alternatives; benefits include reduced water usage, more efficient formation stimulation, and potential for carbon sequestration. Studies indicate that adding nanoparticles (NPs) to CO 2 fracturing fluids significantly enhances foam stability, duration, and pressure build-up during stimulation. This review reports on NPs-enhanced CO 2 foam fracturing to clarify laboratory findings regarding different types of NPs, concentrations, and fluid systems. It details how NPs improve foam performance, particularly foam half-life, and discusses the underlying mechanisms. Future research should focus on the effects of NP size and surface area, NP compatibility under harsh reservoir conditions, the development of advanced treatments and additives, and the expansion of field testing. Overall, NPs-enhanced CO 2 foam fracturing has strong potential to improve the efficiency of unconventional petroleum production.