We show that nitrogen flooding can double matrix permeability of gas shales. In laboratory experiments, nitrogen gas increased permeability in the bedding-perpendicular and bedding-parallel directions by 206% and 234%, respectively. Experiments are performed at constant stress, pore pressure, and temperature. We build a model to show that the permeability enhancement is controlled by the sorptive strain, pore geometry, and the spacing-to-aperture ratio. This work addresses how an organic-poor shale can experience large permeability changes driven by sorption induced strains. We plot methane and helium permeability curves as a function of pore pressure to isolate the portion of permeability evolution controlled by sorption. We independently build strain curves to solve for the sorptive strain and find good agreement between these two methods. This work demonstrates that matrix permeability in gas shales can be doubled, which suggests that ultimate recovery can be improved as well.
|Published - 2020
|SPE/AAPG/SEG Unconventional Resources Technology Conference 2020, URTeC 2020 - Virtual, Online
Duration: Jul 20 2020 → Jul 22 2020
|SPE/AAPG/SEG Unconventional Resources Technology Conference 2020, URTeC 2020
|7/20/20 → 7/22/20
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment