HR: 1330h
AN: H42B-1079    [PDF]
TI: Magnetic Resonance Imaging of Dense and Light Non-Aqueous Phase Liquid in a Rock Fracture: Scaling Implications
AU: * Becker, M W
EM: mwbecker@geology.buffalo.edu
AF: Dept. of Geology, State University of New York at Buffalo, NSC 876, Buffalo, NY 14260 United States
AU: Mazurchuk, R V
EM: richard.mazurchuk@roswellpark.org
AF: Pre- Clinical MR Imaging Facility, Roswell Park Cancer Institute, Elm & Carlton Streets, Buffalo, NY 14263 United States
AU: Spernyak, J
EM: Joseph.Spernyak@RoswellPark.org
AF: Pre- Clinical MR Imaging Facility, Roswell Park Cancer Institute, Elm & Carlton Streets, Buffalo, NY 14263 United States
AB: The migration of non-aqueous phase liquid (NAPL) through fractures is influenced by hydraulic gradient, fracture aperture, surface wettability, and buoyancy. These factors occur at different scales and have varying levels of importance depending upon the constituent fluids (e.g. dense versus light NAPL). Our investigations were conducted in the laboratory at the centimeter scale. Magnetic resonance imaging (MRI) was used to observe the flow of dense (FC-75) and light (dodecane) NAPLs through water-saturated dolomite fractures. MRI was capable of characterizing the fracture geometry and the fluid flow, but was limited by outlet flow conditions in the sample and acquisition times. This method permits observation of two-phase flow under natural wettability and matrix porosity, providing significant advantages over plastic or glass replicas. Animated color images allow dynamic fluid behavior to be observed. We observed dynamic two-phase behavior that was influenced by (1) buoyancy of the NAPL relative to the aqueous phase, (2) fracture aperture distribution, and (3) alteration of wettability by long-term presence of NAPL phase. These results raise issues with respect to both spatial and temporal scale of NAPL transport. Minor changes in fracture aperture and elevation appeared to strongly affect overall NAPL movement, implying that local spatial variations may lead to larger-scale variations in transport behavior. Pre-saturation of the fracture with NAPL also affected transport, implying that the rate at which a NAPL front migrates may influence the capillary resistance to fluid advance.
UR: http://www.geology.buffalo.edu/Research/hydro/MRI.htm
DE: 1832 Groundwater transport
DE: 1894 Instruments and techniques
DE: 5104 Fracture and flow
SC: Hydrology [H]
MN: 2003 Fall Meeting