CO2 SEQUESTRATION POTENTIAL OF TEXAS LOW-RANK COALS
The objectives of this project are to evaluate the feasibility of carbon dioxide (CO{sub 2}) sequestration in Texas low-rank coals and to determine the potential for enhanced coalbed methane (CBM) recovery as an added benefit of sequestration. there were two main objectives for this reporting period. first, they wanted to collect wilcox coal samples from depths similar to those of probable sequestration sites, with the objective of determining accurate parameters for reservoir model description and for reservoir simulation. The second objective was to pursue opportunities for determining permeability of deep Wilcox coal to use as additional, necessary data for modeling reservoir performance during CO{sub 2} sequestration and enhanced coalbed methane recovery. In mid-summer, Anadarko Petroleum Corporation agreed to allow the authors to collect Wilcox Group coal samples from a well that was to be drilled to the Austin Chalk, which is several thousand feet below the Wilcox. In addition, they agreed to allow them to perform permeability tests in coal beds in an existing shut-in well. Both wells are in the region of the Sam K. Seymour power station, a site that they earlier identified as a major point source of CO{sub 2}. They negotiated contracts for sidewall core collection and core analyses, and they began discussions with a service company to perform permeability testing. To collect sidewall core samples of the Wilcox coals, they made structure and isopach maps and cross sections to select coal beds and to determine their depths for coring. On September 29, 10 sidewall core samples were obtained from 3 coal beds of the Lower Calvert Bluff Formation of the Wilcox Group. The samples were desorbed in 4 sidewall core canisters. Desorbed gas samples were sent to a laboratory for gas compositional analyses, and the coal samples were sent to another laboratory to measure CO{sub 2}, CH{sub 4}, and N{sub 2} sorption isotherms. All analyses should be finished by the end of December. A preliminary report shows methane content values for the desorbed coal samples ranged between 330 and 388 scf/t., on ''as received'' basis. Residual gas content of the coals was not included in the analyses, which results in an approximate 5-10% underestimation of in-situ gas content. Coal maps indicate that total coal thickness is 40-70 ft in the Lower Calvert Bluff Formation of the Wilcox Group in the vicinity of the Sam K. Seymour power plant. A conservative estimate indicates that methane in place for a well on 160-acre spacing is approximately 3.5 Bcf in Lower Calvert Bluff coal beds. When they receive sorption isotherm data from the laboratory, they will determine the amount of CO{sub 2} that it may be possible to sequester in Wilcox coals. In December, when the final laboratory and field test data are available, they will complete the reservoir model and begin to simulate CO{sub 2} sequestration and enhanced CH{sub 4} production.
- Research Organization:
- Texas Engineering Experiment Station (US)
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- FC26-02NT41588
- OSTI ID:
- 835874
- Resource Relation:
- Other Information: PBD: 1 Nov 2004
- Country of Publication:
- United States
- Language:
- English
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