| Title | DEM-Based Analysis to Reveal the Effects of Particle Size Distribution on Deformational Behavior of Particulate Packs |
|---|---|
| Authors | Ayat ALASADI, Ahmad GHASSEMI, Dacid POTYONDY, Shahrzad ROSHANKHAH |
| Year | 2025 |
| Conference | Stanford Geothermal Workshop |
| Keywords | Proppants, EGS, particle size distribution, DEM, PFC |
| Abstract | Proppants are widely used to enhance reservoir production by maintaining fracture conductivity in unconventional fossil energy and enhanced geothermal systems (EGS). However, proppants break into fragments under high fracture closure stresses and high reservoir temperatures, reducing the fracture’s hydraulic conductivity. This study uses Itasca’s Particle Flow Code (PFC), which operates based on the discrete element method (DEM) algorithms, to numerically investigate the effects of proppant size distribution on deformational behavior and permeability evolution of particulate packs. The linear and Hertzian contact models are utilized to simulate interactions among rigid and unbreakable particles within the pack where deformations are concentrated at interparticle contacts. The microstructural input parameters of the models are calibrated such that the laboratory uniaxial strain test data on a low-density ceramic (LDC) proppant candidate are reproduced digitally. The evolving porosity due to particle rearrangement is calculated based on the evolving void volume, and the corresponding permeability of the proppant pack is estimated from an empirical correlation, the Kozeny-Carman relation. The results show that the Hertzian contact model captures the effects of particle size distribution (PSD) on the proppant pack’s deformational behavior only up to the yield point where plastic deformations due to particle crushing occur. Our future research will involve modeling other particle types, shapes, and size distributions deforming and crushing under high stresses and temperatures like those encountered in the Utah FORGE EGS. These analyses will provide invaluable insights into the impact of proppant particle shape and size distribution on crush resistance, helping to optimize proppant selection for maintaining fracture conductivity under in-situ conditions. |