skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Influence of carbon dioxide on coal permeability determined by pressure transient methods

Abstract

The permeability of coal samples from Pittsburgh Seam was determined using carbon dioxide as the flowing fluid. The confining pressure was varied to cover a wide range of depths. The permeability was determined as a function of exposure time of carbon dioxide while the confining stress was kept constant. The porosities of the coal samples were found to be very low and most of the samples had porosities less than 1%. The permeability of these coal samples was very low-less than 1μD. Since the objective of this study was to investigate the influence of CO2 exposure on coal permeability, it was necessary to increase the initial permeability of the coal samples by introducing a fracture. A longitudinal fracture was induced mechanically, and CT scans were taken to ensure that the fracture was present throughout the sample and that the sample was not damaged otherwise during the process. In this study, the permeability of coal was determined by using pressure transient methods. Two types of pressure pulses were used: A-spike and Sine-6 pressure transients. It was first established that the permeability of fractured coal samples did not change with exposure time when an inert gas (Argon) was used as the fluidmore » medium in the experiments. However, the permeability of coal samples decreased significantly when carbon dioxide was used as the fluid medium. This reduction can be attributed to the coal swelling phenomenon. The results show that the permeability reduction in fractured coal samples can be over 90% of the original value, and the exposure time for such reductions can range from 1.5 days up to a week, typically about 2 days under laboratory conditions. The permeability decreased significantly with the increase in confining pressure. The higher confining pressure appears to close internal fractures causing a reduction in permeability.« less

Authors:
 [1];  [2];  [2];  [2];  [2];  [2]
  1. West Virginia Univ., Morgantown, WV (United States)
  2. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
Publication Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
Sponsoring Org.:
USDOE Assistant Secretary for Fossil Energy (FE)
OSTI Identifier:
1014902
Report Number(s):
NETL-TPR-2033
Journal ID: ISSN 0166-5162
Resource Type:
Journal Article
Journal Name:
International Journal of Coal Geology
Additional Journal Information:
Journal Volume: 77; Journal Issue: 1-2; Journal ID: ISSN 0166-5162
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; COAL SWELLING; GEOLOGIC SEQUESTRATION; PRESSURE TRANSIENT METHOD; CARBON DIOXIDE; COAL PERMEABILITY

Citation Formats

Siriwardane, Hema, McLendon, Robert, Haljasmaa, Igor, Irdi, Gino, Soong, Yee, and Bromhal, Grant. Influence of carbon dioxide on coal permeability determined by pressure transient methods. United States: N. p., 2009. Web. doi:10.1016/j.coal.2008.08.006.
Siriwardane, Hema, McLendon, Robert, Haljasmaa, Igor, Irdi, Gino, Soong, Yee, & Bromhal, Grant. Influence of carbon dioxide on coal permeability determined by pressure transient methods. United States. https://doi.org/10.1016/j.coal.2008.08.006
Siriwardane, Hema, McLendon, Robert, Haljasmaa, Igor, Irdi, Gino, Soong, Yee, and Bromhal, Grant. 2009. "Influence of carbon dioxide on coal permeability determined by pressure transient methods". United States. https://doi.org/10.1016/j.coal.2008.08.006.
@article{osti_1014902,
title = {Influence of carbon dioxide on coal permeability determined by pressure transient methods},
author = {Siriwardane, Hema and McLendon, Robert and Haljasmaa, Igor and Irdi, Gino and Soong, Yee and Bromhal, Grant},
abstractNote = {The permeability of coal samples from Pittsburgh Seam was determined using carbon dioxide as the flowing fluid. The confining pressure was varied to cover a wide range of depths. The permeability was determined as a function of exposure time of carbon dioxide while the confining stress was kept constant. The porosities of the coal samples were found to be very low and most of the samples had porosities less than 1%. The permeability of these coal samples was very low-less than 1μD. Since the objective of this study was to investigate the influence of CO2 exposure on coal permeability, it was necessary to increase the initial permeability of the coal samples by introducing a fracture. A longitudinal fracture was induced mechanically, and CT scans were taken to ensure that the fracture was present throughout the sample and that the sample was not damaged otherwise during the process. In this study, the permeability of coal was determined by using pressure transient methods. Two types of pressure pulses were used: A-spike and Sine-6 pressure transients. It was first established that the permeability of fractured coal samples did not change with exposure time when an inert gas (Argon) was used as the fluid medium in the experiments. However, the permeability of coal samples decreased significantly when carbon dioxide was used as the fluid medium. This reduction can be attributed to the coal swelling phenomenon. The results show that the permeability reduction in fractured coal samples can be over 90% of the original value, and the exposure time for such reductions can range from 1.5 days up to a week, typically about 2 days under laboratory conditions. The permeability decreased significantly with the increase in confining pressure. The higher confining pressure appears to close internal fractures causing a reduction in permeability.},
doi = {10.1016/j.coal.2008.08.006},
url = {https://www.osti.gov/biblio/1014902}, journal = {International Journal of Coal Geology},
issn = {0166-5162},
number = 1-2,
volume = 77,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2009},
month = {Thu Jan 01 00:00:00 EST 2009}
}