Investigation of CO2 injection induced coal-gas interactions

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

Research output: Contribution to conferencePaperpeer-review

6 Scopus citations

Abstract

Understanding the role of the co- and counter-diffusive properties of CO2 and CH4 in coal has important implications for enhanced coalbed methane recovery (ECBM) and CO2 sequestration in coals and for related issues of gas outbursts during mining. This study addresses how coal-gas interactions affect CO2 injectivity, in particular the roles of coal deformation, gas flow, CH4-CO 2 counter-diffusion and gas absorption/desorption on the evolution of transport and mechanical properties of fractured coals, and therefore on ECBM recovery. A fully coupled coal deformation, gas flow, CH4-CO 2 counter-diffusion and gas absorption/desorption finite element (FE) model was developed to investigate the combined net effects on evolutions of CO2 injection related parameters. The FE model was successfully applied to match the experimental data; and a field scale model was constructed to quantify CO2 injection rate and other transport parameters for ECBM under in-situ conditions. Model results indicated that (1) Coal rank has a converse influence on the CO2 injection performance, lower coal rank reservoir could be more suitable to carry out CO2-ECBM technology; (2) Initial permeability has positive impact on the performance of CO 2 replacing methane. This finding also has an important indication for the implementation of this technology in shale and other low permeability media; (3) CO2 injection is very sensitive to changes in the injection gas Langmuir strain constants, so trying to reduce the resultant strain constant, such as using mixed gases like N2 and CO2 or flue gas, is an efficient solution to improve the methane recovery efficiency.

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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