Simulating Hydraulic Fracturing Dynamics Considering Dynamic Biot’s Poroelasticity and Coupled Plasticity

Simulating Hydraulic Fracturing Dynamics Considering Dynamic Biot’s Poroelasticity and Coupled Plasticity–Damage Permeability

Ai, Shu-Gang / Gao, Ke

Abstract

Fluid injection is widely used to enhance permeability in rock formations by creating or dilating transport pathways for resources such as oil, gas, heat, or CO₂. The dynamic propagation of damage induced by fluid injection is governed by fluid flow, dynamic poroelastic deformation, mixed tensile and shear failure, and damage-induced antipermeability degradation. However, the transition from elastoplastic deformation to mixed-mode failure, as well as the induced dynamics, remains ambiguous. This study combines the dynamic Biot’s poroelasticity and coupled Drucker–Prager plasticity, Grady–Kipp damage, and antipermeability degradation to simulate dynamic hydraulic fracturing. An explicit predictor–corrector scheme was employed to solve the dynamics of saturated porous media and identify the key factors controlling dynamic damage propagation. The proposed model was tested on soil column consolidation and rock hydraulic fracturing driven by a pre-existing crack, demonstrating good agreement between the numerical and experimental results. Simulation results indicate that damage zones facilitate preferential flow during fluid injection due to damage-induced degradation. The most extensive damage zone is observed under strong damage–permeability coupling. Shear plasticity, tensile damage, and induced seismicity are dominated by fracturing dynamics induced by fluid injection. Oscillations in the temporal–spatial evolution of damaged and plastic points, cumulated potency, and moment magnitude confirm the fracturing dynamics. Shorter injection times result in stronger dynamics and more significant damage propagation. The period of oscillations in cumulated potency increases with injection time while their amplitude gradually decreases due to energy release. These findings highlight injection-induced fracturing dynamics, offering novel insights into the dynamic propagation of damage coupled with matrix antipermeability degradation.

The insights gained from this study on dynamic hydraulic fracturing have significant practical implications for industries utilizing fluid injection to enhance permeability in rock formations. By understanding the factors controlling dynamic damage propagation, engineers can optimize fluid injection strategies to maximize permeability enhancement while minimizing unintended damage. The findings regarding the influence of injection time on fracturing dynamics can inform the design of injection protocols to control the extent and impact of induced seismicity. Moreover, the study’s validation of the proposed model against experimental and numerical results provides a reliable tool for predicting damage zones and preferential flow paths, which can be used in planning and managing fluid injection operations. This research contributes to safer and more efficient extraction of subsurface resources and the effective sequestration of CO₂, ultimately aiding in the advancement of sustainable energy practices and environmental protection.