Impact Of Friction Coefficient On The Mesoscale Structure Evolution Under Shearing Of Granular Plugging Zone

Forming a high-strength granular plugging zone is important to lost circulation control success in fractured oil, gas, and geothermal resources. The stability of mesoscale force chain network, which is the way to transferring contact force between particles, determines granular plugging zone strength. However, the effect of granular performance parameters on mesoscale structure stability of plugging zone remains unclear. In this work, a photoelastic method is adopted to visually observe mesoscale structure evolution accounting for fracture occurrence, plugging zone stress condition and failure mode. Results show that force chains display better symmetry along the shear direction and distribute more uniformly in a plugging zone formed with higher friction coefficient particles. Contact force transmission causes lower friction coefficient particles siding and induces plugging zone instability. Symmetry and uniformity of the strong force chain network are the two key optimal distribution parameters to improve plugging zone stability and materials selection. (c) 2021 Elsevier B.V. All rights reserved.