Nanoscale coal deformation and its geomechanics effect on pore structure evolution under hydrostatic and uniaxial compression conditions

Rui Zhang, Shimin Liu

Research output: Contribution to conferencePaper

1 Scopus citations

Abstract

Nanoscale coal deformation will affect geomechanics response of coal with gas injection coupled with the external stress condition. In this study, in situ small-angle neutron scattering (SANS) is used to characterize the nanopore structure evolution of San Juan coal under hydrostatic gas injection and Illinois coal under uniaxial compression, respectively. Argon pressurization can induce pore contraction in San Juan coal. Both methane and carbon dioxide injection can induce pore shrinkage due to the combined effects of hydrostatic pressurization, adsorbed molecule occupation, and sorption-induced matrix swelling. An apparent anisotropic nanopore structure is shown in Illinois coal cut perpendicular to bedding, in which the degree of anisotropy generally increases with increasing pore size. Uniaxial compression perpendicular to the bedding can cause a “two-stage” pore contraction in both the directions perpendicular and parallel to the bedding. The degree of anisotropy tends to decrease with increasing uniaxial stress during the nanopore deformation but with variations among different deformation stages and pore sizes.

Original languageEnglish (US)
StatePublished - Jan 1 2019
Event53rd U.S. Rock Mechanics/Geomechanics Symposium - Brooklyn, United States
Duration: Jun 23 2019Jun 26 2019

Conference

Conference53rd U.S. Rock Mechanics/Geomechanics Symposium
CountryUnited States
CityBrooklyn
Period6/23/196/26/19

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All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics

Cite this

Zhang, R., & Liu, S. (2019). Nanoscale coal deformation and its geomechanics effect on pore structure evolution under hydrostatic and uniaxial compression conditions. Paper presented at 53rd U.S. Rock Mechanics/Geomechanics Symposium, Brooklyn, United States.