GEOLOGICAL SURVEY OF ALABAMA
CARBON SEQUESTRATION RESEARCH
Discrete Fracture Network Models for Risk Assessment of Carbon Sequestration in Coal
A study sponsored by the
Project start date: 5/1/05
Coal is an important sink for the sequestration of carbon dioxide, and software technology is being developed to assess the potential risks associated with carbon sequestration in coal. Natural fractures provide important conduits for fluid flow in coal-bearing strata, and these fractures present the most tangible risks for the leakage of injected carbon dioxide. Discrete fracture network (DFN) models have been used successfully to assess leakage risks associated with hydraulic fracturing and coalbed methane production, and these models show promise for assessing risks associated with carbon sequestration in coal. The objectives of this project were to develop a software package called DFNModeler for risk assessment and to use this software to assess risks in the Black Warrior basin of Alabama, where coal-bearing strata have high potential for carbon sequestration and enhanced coalbed methane recovery.
This project was sponsored primarily by the National Energy Technology Laboratory of the U.S. Department of Energy and was conducted by the Geological Survey of Alabama in partnership with the University of Alabama and Jim Walter Resources, Incorporated. Major activities included developing software for constructing DFN models, developing OpenGL tools for the visualization and analysis of DFN models, and developing software to facilitate flow modeling of carbon dioxide and water. Data sets from outcrops and cores in the Black Warrior basin were used to develop DFN models, to develop flow models, and to assess potential risks associated with carbon sequestration. Geologic and hydrologic data sets were also used to test and validate the models and to aid in risk assessment.
Development of DFNModeler software was originally sponsored by the U.S. Environmental Protection Agency as an OpenGL front end to FracMan software, which is available from Golder Associates. Under the NETL-sponsored program, DFNModeler has been expanded into a stand-alone software package that is tailored specifically toward understanding fracture networks and the flow of water and gas in coal-bearing formations.
Capabilities include the realization and visualization of discrete fracture networks in coal-bearing strata. Fractures and beds can be color-contoured according to aperture, transmissivity, and storativity. The software also enables compartmentalization analysis, and export of DFN models to multi-phase flow modeling packages that are commonly used in carbon sequestration studies, such as TOUGH2.
This project included a vigorous technology transfer program that is designed to support the demonstration and commercialization of carbon sequestration technology. An advisory group consisting of the project team, coalbed methane producers, a utility representative, and researchers involved in reservoir simulation helped guide the project and provided a forum for communication among stakeholders two can implement carbon sequestration technology. Results are being presented at technical meetings and workshops and are being published in technical journals and meeting proceedings. This website is also central to technology transfer activities, and links to relevant reports and materials are given below. At the close of this project, DFNModeler software will be made available for download as freeware from this website.
Guohai Jin, Pashin, J. C., and Payton, J. W., 2003, Application of discrete fracture network models to coalbed methane reservoirs of the Black Warrior basin: Tuscaloosa ,Alabama, University of Alabama College of Continuing Studies, 2003 International Coalbed Methane Symposium Proceedings, Paper 0321, 13 p. (PDF; 31.7 Mb).
Pashin, J. C., Guohai Jin, and Payton, J. W., 2004, Three-dimensional computer models of natural and induced fractures in coalbed methane reservoirs of the Black Warrior basin: Alabama Geological Survey Bulletin 174, 62 p. Available for purchase from the Geological Survey of Alabama Publications Sales Office.
Guohai Jin and Pashin, J. C., 2007, DFNModeler: an efficient discrete fracture network modeler: Tuscaloosa, Alabama, University of Alabama College of Continuing Studies, 2007 International Coalbed Methane Symposium Proceedings, Paper 0709, 16 p (PDF; 0.7 Mb).
Guohai Jin and Pashin, J. C., 2008, Discrete fracture network models of the SECARB carbon sequestration test site, Deerlick Creek Field, Black Warrior Basin, Alabama: Tuscaloosa, Alabama, University of Alabama, College of Continuing Studies, 2008 International Coalbed & Shale Gas Symposium Proceedings, paper 0821, 8 p (PDF; 1.9 Mb).
Pashin, J. C., Guohai Jin, Chunmiao Zheng, Song Chen, and McIntyre, M. R., 2008, Discrete fracture networks for Risk Assessment of Carbon Sequestration in Coal: Final Technical Report, U.S. Department of Energy, National Energy Technology Laboratory, Award DE-FC26-05NT42435, 118 p (PDF; 12.8 Mb).
Jack C. Pashin, Geological Survey of Alabama (Principal investigator; coal and petroleum geology)
Chunmiao Zheng, University of Alabama (Co-principal investigator; hydrogeology, software development)
Guohai Jin, Geological Survey of Alabama (Structural geology, software development)
Marcella McIntyre, Geological Survey of Alabama (Structural geology)
Song Chen, University of Alabama (Hydrogeology, software development)
Marty G. Gates, Geological Survey of Alabama (Structural geology)
Richard E. Carroll, Geological Survey of Alabama (Coal geology)
DOE Contracting Officer Representative
Karen Cohen, National Energy Technology Laboratory
Project Advisory Group
Terry Burns, Geomet Operating Company
Richard Esposito, Southern Company
Richard H. Groshong, Jr., 3D Structure Research
Larry Knox, Dominion Exploration and Production
Scott Reeves, Advanced Resources International
Duane Smith, National Energy Technology Laboratory
Yu-Shu Wu, Lawrence Berkeley National Laboratory
This material is based upon work supported by the Department of Energy National Energy Technology Laboratory under Award Number DE-FC26-05NT42435.
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