About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract

AAPG Bulletin, V. 98, No. 2 (February 2014), P. 395420.

Copyright copy2014. The American Association of Petroleum Geologists. All rights reserved.

DOI:10.1306/07021312128

Gas saturation and CO2 enhancement potential of coalbed methane reservoirs as a function of depth

Yves Gensterblum,1 Alexej Merkel,2 Andreas Busch,3 Bernhard M. Krooss,4 Ralf Littke5

1Energy and Mineral Resources (EMR) Group, Institute of Geology and Geochemistry of Petroleum and Coal (GGPC), RWTH Aachen University, Aachen, Germany; yves.gensterblum@emr.rwth-aachen.de
2Energy and Mineral Resources (EMR) Group, Institute of Geology and Geochemistry of Petroleum and Coal (GGPC), RWTH Aachen University, Aachen, Germany; alexej.merkel@emr.rwth-aachen.de
3Shell Global Solutions International, Rijswijk, The Netherlands; Andreas.Busch@shell.com
4Energy and Mineral Resources (EMR) Group, Institute of Geology and Geochemistry of Petroleum and Coal (GGPC), RWTH, Aachen University, D-52056 Aachen, Germany; bernhard.krooss@emr.rwth-aachen.de
5Energy and Mineral Resources (EMR) Group, Institute of Geology and Geochemistry of Petroleum and Coal (GGPC), RWTH Aachen University, Aachen, Germany; ralf.littke@emr.rwth-aachen.de

ABSTRACT

The influence of moisture, temperature, coal rank, and differential enthalpy on the methane (CH4) and carbon dioxide (CO2) sorption capacity of coals of different rank has been investigated by using high-pressure sorption isotherms at 303, 318, and 333 K (CH4) and 318, 333, and 348 K (CO2), respectively. The variation of sorption capacity was studied as a function of burial depth of coal seams using the corresponding Langmuir parameters in combination with a geothermal gradient of 0.03 K/m and a normal hydrostatic pressure gradient. Taking the gas content corresponding to 100% gas saturation at maximum burial depth as a reference value, the theoretical CH4 saturation after the uplift of the coal seam was computed as a function of depth. According to these calculations, the change in sorption capacity caused by changing pressure, temperature conditions during uplift will lead consistently to high saturation values. Therefore, the commonly observed undersaturation of coal seams is most likely related to dismigration (losses into adjacent formations and atmosphere). Finally, we attempt to identify sweet spots for CO2-enhanced coalbed methane (CO2-ECBM) production. The CO2-ECBM is expected to become less effective with increasing depth because the CO2-to-CH4 sorption capacity ratio decreases with increasing temperature and pressure. Furthermore, CO2-ECBM efficiency will decrease with increasing maturity because of the highest sorption capacity ratio and affinity difference between CO2 and CH4 for low mature coals.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Protected Document: $10
Internal PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Members Only username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership through the AAPG Members Only program. For more information, contact the AAPG Membership Department at members@aapg.org.

Handsome