CO2 utilization and sequestration potential in deep coal seams: A case study on Carboniferous coals from the Karaganda Basin, Kazakhstan

Journal of CO2 Utilization, vol. 101, pp. 103204

Abstract

Kazakhstan is a major coal producer and emitter of carbon dioxide (CO 2 ), presenting both a challenge and an opportunity for CO₂ utilization and storage. The main goal of this work is to study the feasibility of CO 2 as a feedstock for enhanced coalbed methane recovery (CO 2 -ECBM), as well as the associated geological storage potential of the D6 coal seam in the Karaganda Basin. For this purpose, coal samples were investigated using elemental analysis, Rock-Eval pyrolysis (RE), organic petrography as well as low-pressure (LP: N 2 , CO 2 ), and high-pressure (HP: CO 2 , CH 4 ) sorption tests. Vitrinite reflectance values show that seam D6 reached the medium-volatile bituminous rank. Higher organic matter content significantly increases the LP CO 2 sorption capacity. The adsorption-desorption isotherms of CO 2 recorded under both LP and HP conditions show a hysteresis loop. This is probably due to interactions between CO 2 and functional groups leading to enhanced physisorption at LP and chemisorption and matrix swelling at HP conditions. This effect is favorable for storage purposes as it implies safe CO 2 trapping even at reduced reservoir pressure. The CBM potential of seam D6 is estimated at 9 billion m 3 initial gas and 360 million m 3 producible gas in place. Estimates of the adsorptive and total CO 2 storage capacity yielded 1.1 and 3.6 gigatons (Gt), respectively. With this considerable total storage capacity, Kazakhstan's current annual CO 2 emissions could be stored for 14 years. This study highlights how CO 2 can be effectively utilized as a feedstock to enhance methane recovery while achieving long-term CO 2 sequestration.

Authors 8

1. Majid Safaei-Farouji corresponding

   Montanuniversität Leoben

   Affiliation as printed

   Chair of Energy Geosciences, Department of Applied Geosciences and Geophysics, Montanuniversität Leoben, Leoben 8700, Austria

2. David Misch

   Montanuniversität Leoben

   Affiliation as printed

   Chair of Energy Geosciences, Department of Applied Geosciences and Geophysics, Montanuniversität Leoben, Leoben 8700, Austria

3. Reinhard F. Sachsenhofer

   Montanuniversität Leoben

   Affiliation as printed

   Chair of Energy Geosciences, Department of Applied Geosciences and Geophysics, Montanuniversität Leoben, Leoben 8700, Austria

4. Nikolaos Kostoglou

   Montanuniversität Leoben

   Affiliation as printed

   Department of Materials Science, Montanuniversität Leoben, Leoben 8700, Austria

5. Garri Gaus Aachen Energy and Mineral Resources Group (EMR) Institute of Organic Biogeochemistry in Geosystems

   Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies IEG · Fraunhofer-Gesellschaft · RWTH Aachen University

   Affiliation as printed

   Energy and Mineral Resources Group (EMR), Institute of Organic Biogeochemistry in GeoSystems, RWTH Aachen University, Lochnerstraße 4-20, Aachen 52056, Germany

   Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies, Aachen 52062, Germany

6. Thorsten Bauersachs Aachen Energy and Mineral Resources Group (EMR) Institute of Organic Biogeochemistry in Geosystems

   RWTH Aachen University

   Affiliation as printed

   Energy and Mineral Resources Group (EMR), Institute of Organic Biogeochemistry in GeoSystems, RWTH Aachen University, Lochnerstraße 4-20, Aachen 52056, Germany

7. Medet Junussov

   Nazarbayev University

   Affiliation as printed

   School of Mining and Geosciences, Nazarbayev University, Astana, Kazakhstan

8. Milovan Fustic

   University of Calgary · Nazarbayev University

   Affiliation as printed

   Department of Earth, Energy, and Environment, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4 Canada

   School of Mining and Geosciences, Nazarbayev University, Astana, Kazakhstan