Particula: A simulator tool for computational rock physics of granular media

Abstract

Granular dynamics simulations provide insights to the contact-scale physics of loose sediments. However, simulations using identical spherical grains do not reflect characteristics observed in natural sediments, such as pack sorting, grading, grain sphericity, and grain roundness. We have developed software to create 3D grain packs of a range of regular and irregular shapes with geologically realistic variations in sorting and grading. An efficient approach is used to create multiple realizations of nonspherical irregularly shaped grains using coherent noise modification of the spherical grain surface. The discrete-element method is used to assemble the grain pack with different depositional styles by letting grains fall under the influence of gravity. Characterization of various parameters of random loose and dense grain packs, and comparison with previous studies, helps to establish the validity, flexibility, and consistency of the simulator. The output of this software is a digital grain pack, including metadata such as contacts and coordinates, that can be studied further using other analysis tools, e.g., by conducting fluid flow, mechanical, or electrical simulations.