Gas saturated coal failure envelope establishment through single core multistage triaxial loading tests

Long Fan, Shimin Liu

Research output: Contribution to conferencePaper

Abstract

Coal properties may behavior in a different way under in situ reservoir conditions from other traditional reservoirs because of the combined effects of effective stress and sorbing-gas induced matrix property changes.Multistage triaxial testing can generate a full failure envelope using a single plug core, especially for the test when there is insufficient number of cores to run the standard triaxial tests. In this paper, a series of multistage triaxial compression testes of gas saturated coal cores were conducted based on ISRM standard procedures to determine the mechanical properties of reservoir coal formations as a function of confining stress and gas pressure.Coal strength deterioration due to phase-dependent gas adsorption was investigated.It demonstrated that coal strength with adsorbing gas injection had a positive correlation with confining stress; coalspecimen showed plasticization under a higher confining stress condition; anthracite coal has a strong adsorption effect on CO2 and the free gas phase CO2 adsorption can cause a dramatic peak strength deterioration; coal strength deterioration was exacerbated with respect to gas pressure. However, as the gas was in subcritical phase, gas density increasing induced hardening effect may be dominant; supercritical CO2 led to a strong softening on coal skeleton and resulted in a plasticization of coal under a quite small confining stress condition.

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

Fingerprint

loading test
Coal
coal
envelopes
Gases
gases
gas
confining
deterioration
Deterioration
adsorption
gas pressure
anthracite
testes
gas injection
Adsorption
Density of gases
Gas adsorption
gas density
triaxial test

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics

Cite this

Fan, L., & Liu, S. (2019). Gas saturated coal failure envelope establishment through single core multistage triaxial loading tests. Paper presented at 53rd U.S. Rock Mechanics/Geomechanics Symposium, Brooklyn, United States.
Fan, Long ; Liu, Shimin. / Gas saturated coal failure envelope establishment through single core multistage triaxial loading tests. Paper presented at 53rd U.S. Rock Mechanics/Geomechanics Symposium, Brooklyn, United States.
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Fan, L & Liu, S 2019, 'Gas saturated coal failure envelope establishment through single core multistage triaxial loading tests', Paper presented at 53rd U.S. Rock Mechanics/Geomechanics Symposium, Brooklyn, United States, 6/23/19 - 6/26/19.

Gas saturated coal failure envelope establishment through single core multistage triaxial loading tests. / Fan, Long; Liu, Shimin.

2019. Paper presented at 53rd U.S. Rock Mechanics/Geomechanics Symposium, Brooklyn, United States.

Research output: Contribution to conferencePaper

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AU - Liu, Shimin

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Fan L, Liu S. Gas saturated coal failure envelope establishment through single core multistage triaxial loading tests. 2019. Paper presented at 53rd U.S. Rock Mechanics/Geomechanics Symposium, Brooklyn, United States.