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 03.21.2014 at 8:55am
Haiying Huang, Ph.D.
School of Civil and Environmental Engineering
Georgia Institute of Technology
Fundamental understanding of the coupled displacement process of fluid injection into dense granular media is critical to many geological and engineering applications such as hydraulic fracturing, water flooding and drill cuttings reinjection in weakly cemented and highly permeable formations. Due to the strong coupling between mechanical deformation and fluid flow as well as the highly nonlinear constitutive behaviors of the soft formations, modeling of the injection process remains a challenging task.
Integrated theoretical and experimental analyses are carried out in this work to investigate the fundamental failure mechanisms and flow patterns involved in the injection process. The experimental work is first conducted with aqueous glycerin solutions, utilizing a novel setup based on a Hele-Shaw cell filled with dense dry sands. The two dimensional nature of the setup allows direct visualization and image analysis of the real-time fluid and grain kinematics. The experimental results reveal that the fluid flow patterns show a transition from simple radial flow to a ramified morphology while the granular media behaviors change from that of rigid porous media to localized failure that lead to development of fluid channels. Based on the failure/flow patterns, three distinct failure/flow regimes can be identified in addition to the simple radial flow regime, namely, an infiltration-dominated regime, a grain displacement-dominated regime, and a viscous fingering-dominated regime. Experiments are also performed to investigate the effects of non-Newtonian fluid rheology as well as the addition of silica flour in the granular medium on pattern formation.
The injection process is analyzed numerically using the discrete element method code PFC3D coupled with a fixed coarse grid scheme based on computational fluid dynamics and PFC2D coupled with a pore network modeling scheme. The numerical results from the two complimentary methods reproduce phenomena consistent with the laboratory experiments. We show that existence of the distinct failure/flow regimes emerge as a result of competition among three energy dissipation mechanisms, namely, viscous dissipation through infiltration, dissipation through grain displacements, and viscous dissipation through flow in thin channels.
About Dr. Haiying Huang
Dr. Haiying Huang is an Associate Professor in the GeoSystems group in the School of Civil and Environmental Engineering in Georgia Tech. She obtained her Ph.D in Geological Engineering from the University of Minnesota in 1999. She then worked as a senior engineer in Schlumberger Oilfield Services in Sugar Land, TX from 2000 to 2006 before she joined the faculty in Georgia Tech in 2007. Dr. Huang is a recipient of the NSF CAREER award in 2011.