Bed strength in sheared beds of mono- and bi-disperse particles: Dependence on geometrical and mechanical properties of constituent particles

Temporary plugging zones are low-permeability fracture-scale plugs ‘assembled’ in situ by injecting polymer particles into petroleum reservoirs. We applied the rolling resistance linear model to simulate the shear strength of a rectangular packed bed, our model for a temporary plugging zone, comprising either uniform-sized particles or a binary mixture of larger bridging particles and smaller filling particles. Simulation results show that the strength of uniform beds increases with the size, the aspect ratio, the friction coefficient, and the Young’s modulus of the particles. The strength of binary packed beds first increased and then decreased as the fractional volume of the domain occupied by filling particles increased. Maximum strength was achieved when bridging particles have uniform Young’s modulus and aspect ratio but a range of friction coefficients, and their friction coefficient, Young’s modulus and aspect ratio are 21%, 17% and 18% larger than those of filling particles.