Dual poroelastic response of coal seam to CO2 injection

Yu Wu, Jishan Liu, Zhongwei Chen, Derek Elsworth, Luke Connell, Zhejun Pan

Research output: Contribution to conferencePaper

3 Scopus citations

Abstract

Although the influence of gas sorption-induced coal deformation on porosity and permeability has been widely studied, these studies are all under the invariant total stress condition. According to the principle of effective stress, the induced coal deformation is determined by the change in effective stress, which can be replaced by the change in pore pressure, under the assumption of null change in total stress. This is why terms representing effective stress or total stress are absent in all of these existing permeability models. In our previous work (Zhang et al, 2008), this assumption was relaxed and a new porosity and permeability model was derived. The FE model was also applied to quantify the net change in permeability, the gas flow, and the resultant deformation in a coal seam. In this work, the general porosity and permeability model was modified to represent both the primary medium (coal matrix) and the secondary medium (fractures), and implemented into a fully coupled coal deformation, CO2 flow and transport in the matrix system, and CO2 flow and transport in the fracture system model. The novel dual-poroelastic model was applied to quantify the mechanical responses of coal seam to the CO2 injection under in situ stress conditions. The simulation results illustrate how the CO2 injectivity is controlled both by the competition between the effective stress and the gas transport induced volume change within the matrix system and by the dynamic interaction between the matrix system and the fracture system.

Original languageEnglish (US)
StatePublished - Nov 27 2009
Event43rd U.S. Rock Mechanics Symposium and 4th U.S.-Canada Rock Mechanics Symposium - Asheville, NC, United States
Duration: Jun 28 2009Jul 1 2009

Other

Other43rd U.S. Rock Mechanics Symposium and 4th U.S.-Canada Rock Mechanics Symposium
CountryUnited States
CityAsheville, NC
Period6/28/097/1/09

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geology
  • Geotechnical Engineering and Engineering Geology

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    Wu, Y., Liu, J., Chen, Z., Elsworth, D., Connell, L., & Pan, Z. (2009). Dual poroelastic response of coal seam to CO2 injection. Paper presented at 43rd U.S. Rock Mechanics Symposium and 4th U.S.-Canada Rock Mechanics Symposium, Asheville, NC, United States.