Soft interface instability and gas flow channeling in low-permeability deformable media

Journal Article · Sun Dec 01 00:00:00 EST 2024 · Geomechanics for Energy and the Environment

DOI:https://doi.org/10.1016/j.gete.2024.100622· OSTI ID:2574185

Wang, Yifeng; Hadgu, Teklu; Faybishenko, Boris; Harrington, Jon; Tamayo-Mas, Elena; Kuhlman, Kristopher L; Jove-Colon, Carlos F

Understanding gas percolation through a clay layer or a shale formation is of great importance for the development of a geologic repository for nuclear waste disposal, a subsurface system for gas storage, and an engineering approach for hydrocarbon extraction from unconventional reservoirs. Gas injection experiments have revealed complex dynamic behaviours of gas percolation through water saturated compacted bentonite, characterized by a high breakthrough pressure, rapid breakthrough, a pressure/stress decay after the breakthrough, a relatively high migration rate, high-frequency periodic/nonperiodic variations in flow rate, stepwise rate reductions during relaxation, and low gas saturation over the whole process, all indicating channelling nature of the processes. Using linear stability analyses, we show that this channelling can autonomously emerge from the instability of the deformable interface between the injected gas and the compacted bentonite matrix driven by local stress concentration, pore dilation, and hydrologic gradient. Channel patterns formed would possess a fractal geometry. We further show that, once a percolating channel is established, the gas injected would percolate through the channel in a chain of gas bubbles, also due to the interface instability, resulting in periodic/chaotic variations in gas flow rate. Our work provides a unified explanation for key features observed for gas percolation in low-permeability deformable media. The work also suggests a possibility of designing an engineered barrier system for a nuclear waste repository that can have controllable gas release while limit water transport.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2574185
• Journal Information: Geomechanics for Energy and the Environment, Journal Name: Geomechanics for Energy and the Environment Vol. 40
• Country of Publication: United States
• Language: English

Related Subjects

Bentonite
Buffer material
Dynamics
Gas migration
Nonlinear
Nuclear waste disposal
Subsurface gas storage