From Bureau of Economic Geology, The
University of Texas at Austin (www.beg.utexas.edu).
For more information, please contact the author.
Bureau Seminar, March 21, 2014
Link to streaming video: available 03.28.2014 at 8:55am
Dr. D. Nicolás Espinoza
Petroleum and Geosystems Engineering
University of Texas at Austin
The growth of natural gas recovery from unmineable coal seams has motivated the investigation of the gas sorption and swelling properties of coal, since those properties play a critical role on the evolution of seam gas permeability. The gas in coal seams is accumulated in pores with a variety of sizes, from nano-sized coal matrix pores to mm-sized coal fractures. Sorption in micropores involves changes in "surface" energy that lead to mechanical couplings that upscale as strains or stresses. Experimental results on various coal samples put in evidence this coupling and show that adsorption-induced stresses can affect significantly the effective stress in coal seams. A double porosity poromechanical model suitable for fractured coal matrix lets us predict strains, stresses upon sorption and desorption. These predictions serve to estimate permeability through a permeability-stress relationship. Together, the modeling and experimental characterization let us understand better sorption phenomena in organic rocks and the geomechanics of coal seams in views of Coal Bed Methane recovery.
About Dr. D. Nicolás Espinoza
Dr. D. Nicolás Espinoza is an Assistant Professor in the Petroleum and Geosystems Department at The University of Texas at Austin. Dr. Espinoza earned his Civil Engineering diploma from Universidad Nacional de Córdoba in 2006, and his MS and PhD degrees from the Georgia Institute of Technology in 2008 and 2011. His primary research interests include Mechanics and Physics of natural porous solids and granular media, including applications to wellbore stability, methane recovery from microporous organic rocks, methane hydrate-bearing sediments, and carbon geological storage. Dr. Espinoza has co-authored a number of peer-reviewed journal articles, served as an expert reviewer for several scientific and engineering journals, and given seminars at various leading research and educational institutions.