3D DEM analysis of analogue proppant–fractured rock system interaction

We investigated the interaction of proppant simulant (impactor) colliding on the surface of a fractured rock by performing 3-dimensional discrete-based numerical simulations. The fractured rock represented a medium-strength clastic material, and the linear parallel bond contact model was implemented to simulate the bonding properties. The ratio of the impactor to rock particle size was equal to 30, which represents, based on the relative dimensions of the problem, typical proppants of 40/70 mesh colliding on fine-grained siltstone. A parametric study was conducted, taking into account the influence of existing fractures within the rock mass as well as their aperture and distance from the impact zone. Significant differences were observed based on the collision velocity (with a distinction in low- and high-velocity impacts), even for intact rock simulations, while, because of the second-order roughness of the rock due to its clastic nature, the impacts were oblique, resulting in the partition of the total kinetic energy. Energy losses, penetration depth, stress transmission through the rock mass, and the influence of the structural characteristics of the analogue rock were systematically investigated to provide some insights into the fundamental contributing mechanisms of impactor-fracture rock interactions.