Abstract: An end compaction point of a clastic sediment within a subsurface region is predicted by establishing a first grain size distribution, wherein the first grain size distribution is a measured grain size distribution, or a predicted grain size distribution. A discrete element model of the subsurface region is initialized, wherein the model comprises a model volume including a base, periodic horizontal boundaries, and soft objects representative of particles of the first grain distribution at a predetermined porosity. A final packing state of the clastic sediment is predicted by iteratively running the model, wherein the final packing state of the clastic sediment is based on packing of the soft objects with a pack and based on the first grain size distribution, wherein soft objects within the model are capable of overlapping with adjacent soft objects within the model.