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Title: Hydrogeochemistry and coal-associated bacterial populations from a methanogenic coal bed

Biogenic coalbed methane (CBM), a microbially-generated source of natural gas trapped within coal beds, is an important energy resource in many countries. Specific bacterial populations and enzymes involved in coal degradation, the potential rate-limiting step of CBM formation, are relatively unknown. The U.S. Geological Survey (USGS) has established a field site, (Birney test site), in an undeveloped area of the Powder River Basin (PRB), with four wells completed in the Flowers-Goodale coal bed, one in the overlying sandstone formation, and four in overlying and underlying coal beds (Knoblach, Nance, and Terret). The nine wells were positioned to characterize the hydraulic conductivity of the Flowers-Goodale coal bed and were selectively cored to investigate the hydrogeochemistry and microbiology associated with CBM production at the Birney test site. Aquifer-test results indicated the Flowers-Goodale coal bed, in a zone from about 112-120 m below land surface at the test site, had very low hydraulic conductivity (0.005 m/d) compared to other PRB coal beds examined. Consistent with microbial methanogenesis, groundwater in the coal bed and overlying sandstone contain dissolved methane (46 mg/L average) with low δ13C values (-67‰ average), high alkalinity values (22 meq/kg average), relatively positive δ13C-DIC values (4‰ average), and no detectable highermore » chain hydrocarbons, NO3-, or SO42-. Bioassay methane production was greatest at the upper interface of the Flowers-Goodale coal bed near the overlying sandstone. Pyrotag analysis identified Aeribacillus as a dominantin situ bacterial community member in the coal near the sandstone and statistical analysis indicated Actinobacteria predominated coal core samples compared to claystone or sandstone cores. These bacteria, which previously have been correlated with hydrocarbon-containing environments such as oil reservoirs, have demonstrated the ability to produce biosurfactants to break down hydrocarbons. As a result, identifying microorganisms involved in coal degradation and the ydrogeochemical conditions that promote their activity is crucial to understanding and improving in situ CBM production.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [2] ;  [3] ;  [5] ;  [6] ;  [3] ;  [7]
  1. U. S. Geological Survey, Helena, MT (United States); Montana State Univ., Bozeman, MT (United States)
  2. U. S. Geological Survey, Lakewood, CO (United States)
  3. U. S. Geological Survey, Reston, VA (United States)
  4. Univ. of Arizona, Tucson, AZ (United States)
  5. Montana State Univ., Bozeman, MT (United States)
  6. Univ. of North Carolina, Charlotte, NC (United States)
  7. Montana State Univ., Bozeman, MT (United States); National Center for Genome Resources, Santa Fe, NM (United States)
Publication Date:
OSTI Identifier:
1327452
Grant/Contract Number:
FE0026155; FC26-04NT42262; AC02-05CH11231; EAR-1322805
Type:
Published Article
Journal Name:
International Journal of Coal Geology
Additional Journal Information:
Journal Volume: 162; Journal Issue: C; Journal ID: ISSN 0166-5162
Publisher:
Elsevier
Research Org:
Montana State Univ., Bozeman, MT (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 58 GEOSCIENCES; 59 BASIC BIOLOGICAL SCIENCES; Powder River Basin; coalbed methane; microbial enhanced CBM (MECoM) technology; test site; biosurfactant; hydrology; hydrogeochemistry