DEM multi-scale insights on the stress, energy and crack propagation in proppant-fractured rock collisions

The collision behavior of an impactor (proppant simulant) colliding on weak clastic rock with pre-existing microcracks is examined in this work at multi-scales. Using discrete element-based analysis, the linear parallel bond contact model is used to simulate the rock base, while the Hertz-Mindlin contact model is used to capture the non-linear force–displacement relationship between grain-block contacts. A systematic parametric study is conducted to assess the impact of microcrack size, number, angle, and position on the damage potential of the impactor colliding the base rock. The results indicate that some of these parameters significantly influence the damage potential while others have minimal effects. Multiscale assessment is conducted by comparing stress and energy distribution results at the macroscale, penetration and contact formation information at the mesoscale and studying the discrete fracture network at the microscale. The findings of this study provide important insights into the collision behavior of proppants with clastic rocks, particularly during hydraulic fracturing operations and can potentially aid in the modeling of these systems at larger scales.