| Title | Critical Fiber Length and Distribution Effects on Fracture Sealing in Geothermal Systems: A CFD–DEM Study |
|---|---|
| Authors | Zhengxun Hui, Arash Dahi Taleghani |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Fiber-based lost circulation materials (LCMs) are often used to temporarily seal fractures and stabilize the wellbore. However, geothermal environments pose challenges—high temperatures can soften fibers, weaken entanglement and adhesion, and compromise plugging stability. This study employs a coupled Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) framework to simulate the behavior of fiber-laden fluids within a wedge-shaped fracture model. The model integrates buoyancy-driven thermal convection and the Peng–Robinson equation of state to mimic realistic supercritical CO₂ plume dynamics. Results suggest that seal stability deteriorates rapidly under plume-induced thermal and flow disturbances, with a more than 50% reduction in sealing duration compared to isothermal cases. In addition, the maximum plugging pressure drops by approximately 30%, further confirming the destabilizing impact of plume conditions. Our results identify three typical failure modes of plugging structures: (1) periodic vertical oscillations induced by plume shear, leading to internal seal loosening; (2) overall drift or upward migration of the plugging zone; and (3) complete disintegration of fiber bridges under high-velocity CO₂ flow. These mechanisms are driven by the interaction between CO₂’s low viscosity, strong buoyancy, and the thermally weakened inter-fiber cohesion. Unlike earlier models limited to isothermal or single-phase flows, this work captures the multiphysics mechanisms driving instability in realistic geothermal conditions. The findings provide insights and design guidance for improving fiber-based LCM performance in high-temperature drilling applications. |