Feasibility Analysis of Pickering Emulsion as Fracturing Fluid in Shale Gas Reservoir

Aiming at the problems of low proppant-carrying capacity and low fracture conductivity of slick water fracturing fluid, a novel fracturing fluid based on Pickering emulsion was fabricated, which was expected to stabilize and support fractures through the interaction between particles in the emulsion and shale wall surface, so as to improve the fracture conductivity. The rheological, anti-swelling, and filtration properties of the Pickering emulsion as the fracturing fluid were examined. The ability of Pickering emulsion to generate fractures and support them was investigated using the rock mechanics triaxial experimental apparatus. The findings demonstrated that Pickering emulsion had high stability and temperature resistance. The filtration rate of Pickering emulsion is much lower than that of slick water fracturing fluid and guar gum fracturing fluid. The Jamin effect made it difficult for emulsion droplets to through the pore throat, and the pressure-induced formation of filter cakes on the core surface further decreased the rate of filtration. Pickering emulsion had some anti-swelling properties and 20–40% slower expansion rate than slick water fracturing fluid. Pickering emulsion fracturing fluid, on the other hand, has a greater capacity for producing fractures. The shale wall can hold and adsorb the solid particles in the emulsion, which to some extent improved the conductivity of fractures. Pickering emulsion fracturing fluid solves the low viscosity and fracture support issues of slick water fracturing fluid, making it a good candidate for use in hydraulic fracturing for shale gas.