Pore-scale simulation and sensitivity analysis of apparent gas permeability in shale matrix

Pengwei Zhang, Liming Hu, Jay N. Meegoda

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Extremely low permeability due to nano-scale pores is a distinctive feature of gas transport in a shale matrix. The permeability of shale depends on pore pressure, porosity, pore throat size and gas type. The pore network model is a practical way to explain the macro flow behavior of porous media from a microscopic point of view. In this research, gas flow in a shale matrix is simulated using a previously developed three-dimensional pore network model that includes typical bimodal pore size distribution, anisotropy and low connectivity of the pore structure in shale. The apparent gas permeability of shale matrix was calculated under different reservoir pressures corresponding to different gas exploitation stages. Results indicate that gas permeability is strongly related to reservoir gas pressure, and hence the apparent permeability is not a unique value during the shale gas exploitation, and simulations suggested that a constant permeability for continuum-scale simulation is not accurate. Hence, the reservoir pressures of different shale gas exploitations should be considered. In addition, a sensitivity analysis was also performed to determine the contributions to apparent permeability of a shale matrix from petro-physical properties of shale such as pore throat size and porosity. Finally, the impact of connectivity of nano-scale pores on shale gas flux was analyzed. These results would provide an insight into understanding nano/micro scale flows of shale gas in the shale matrix.

Original languageEnglish (US)
Article number104
JournalMaterials
Volume10
Issue number2
DOIs
StatePublished - 2017

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Keywords

  • Apparent permeability
  • Low connectivity
  • Nano-scale gas flow
  • Pore network model
  • Shale gas

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