Geomechanical Modeling of Underground Coal Gasification

Date
2016
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Abstract
The geomechanical responses of a coal seam and its surrounding strata in underground coal gasification (UCG) are significant owing to the high temperature nature of the UCG process and the cavity evolution. In this thesis, the results from a reservoir simulator are coupled with a geomechanical module to solve for the displacement and stress variations. A controlled retracting injection point (CRIP) method is applied in the reservoir simulator to model reactions and geochemistry. The stress solution results of some UCG example problems are discussed by applying three constitutive models of linear elastic, hyperbolic, and elasto-plastic. In a simpler method, shear softening and post-failure behavior of the coal is captured by imposing the stress rebalancing on the linear elastic model to mimic the elasto-plastic solution. Finally, the two compelling factors of high temperature and cavity evolution, which have the highest contributions to the geomechanical responses, are comprehensively investigated in different sensitivity analyses.
Description
Keywords
Energy, Engineering--Chemical, Engineering--Environmental, Engineering--Mechanical, Engineering--Petroleum, Geotechnology, Engineering--Operations Research
Citation
Elahi, S. M. (2016). Geomechanical Modeling of Underground Coal Gasification (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26286