Creating multidirectional fractures through particle jamming

Abstract

Hydraulic fracturing initiates the fractures along the direction of maximum-stress in a plane normal to a borehole by injecting high-pressure fluid. Nucleated fractures enhance permeability around boreholes, facilitating the extraction of various subsurface resources and the injection of storage fluids such as CO2 or H2. However, hydraulic fracturing cannot technically generate fractures in directions other than that of the maximum-stress orientation; therefore, permeability enhancement is also limited along that direction. Here, we show experimentally induced multidirectional fractures using shear thickening fluid (STF) as the fracturing fluid, where its viscosity changes with shear rate owing to jamming of suspended nanoparticles. Laboratory experiments under uniaxial, biaxial, and true-triaxial conditions revealed that solidified STF effectively sealed nucleated fractures, leading to increased borehole pressure, even after the initial fracturing. In contrast, traditional hydraulic fracturing cannot maintain borehole pressure once the first hydraulic fracture is nucleated. This repeated pressure buildup facilitated the generation of multidirectional fractures, significantly increasing permeability in various directions around boreholes and substantially improving access to targeted formations. Consequently, the novel approach of using STF in fracturing successfully overcomes the limitations of traditional hydraulic fracturing techniques, which can increase the efficiency of energy extraction and impoundment to reduce global carbon footprint.