Simulation of shale–proppant interaction in hydraulic fracturing by the discrete element method

• We investigated shale–proppant׳s interaction by our proposed DEM method.
• Results reveal the more soft the shale is, it has a smaller aperture and larger plasticity.
• Results reveal that higher pressure has a smaller aperture and larger plasticity.
• Results reveal the larger proppant has a smaller aperture and larger plasticity.
• The DEM and results can be used to guide hydraulic fracturing operation.

In this paper, a three dimensional discrete element method (3D DEM) was proposed and deployed to simulate shale–proppant interaction in hydraulic fracturing. Shale is represented by particles with cement bond, and proppant is represented by particles without a cement layer. The velocity Verlet method is implemented to substitute the traditional central time integration scheme. The proposed DEM is used to investigate the shale–proppant interactions and evaluate the fracture aperture under different proppant sizes, Young׳s moduli and pressure levels. The results reveal that, the more soft shale particle, the higher pressure and the larger proppant size imply smaller crack aperture and larger plastic zone for other given conditions.