title: Imaging and modeling of flow in porous media using clinical nuclear emission tomography systems and computational fluid dynamics.
abstract: This paper presents experimental and modeling aspects of applying nuclear emission tomography to study fluid flow in laboratory packed porous media columns of the type frequently used in geophysics, geochemistry and hydrology research. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are used as non-invasive tools to obtain dynamic 3D images of radioactive tracer concentrations. Dynamic sequences obtained using18F-FDG PET are used to trace flow through a 5 cm diameter × 20 cm tall sand packed column with and without an impermeable obstacle. In addition, a custom-made rotating column setup placed in a clinical two-headed SPECT camera is used to image99mTc-DTPA tracer propagation in a through-flowing column (10 cm diameter × 30 cm tall) packed with recovered aquifer sediments. A computational fluid dynamics software package FLUENT is used to model the observed flow dynamics. Tracer distributions obtained in the simulations in the smaller column uniformly packed with sand and in the column with an obstacle are remarkably similar to the reconstructed images in the PET experiments. SPECT results demonstrate strongly non-uniform flow patterns for the larger column slurry-packed with sub-surface sediment and slow upward flow. In the numerical simulation of the SPECT study, two symmetric channels with increased permeability are prescribed along the column walls, which result in the emergence of two well-defined preferential flow paths. Methods and results of this work provide new opportunities in hydrologic and biogeochemical research. The primary target application for developed technologies is non-destructive, non-perturbing, quantitative imaging of flow dynamics within laboratory scale porous media systems.
authors.affiliation: Department of Radiotracer Development & Imaging Technology, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS55R0121, Berkeley, CA 94720.
authors.forename: Rostyslav
authors.initials: R
authors.lastname: Boutchko
authors.affiliation: Department of Radiology & Biomedical Imaging, University of California, San Francisco, 505 Parnassus Avenue, M-391 San Francisco, CA 94143.
authors.forename: Vitaliy L
authors.initials: VL
authors.lastname: Rayz
authors.affiliation: Department of Radiotracer Development & Imaging Technology, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS55R0121, Berkeley, CA 94720.
authors.forename: Nicholas T
authors.initials: NT
authors.lastname: Vandehey
authors.affiliation: Department of Radiotracer Development & Imaging Technology, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS55R0121, Berkeley, CA 94720.
authors.forename: James P
authors.initials: JP
authors.lastname: O'Neil
authors.affiliation: Department of Radiotracer Development & Imaging Technology, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS55R0121, Berkeley, CA 94720.
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Budinger
authors.affiliation: Geochemistry Department, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS90R1116, Berkeley, CA 94720.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Nico
authors.affiliation: Department of Earth and Planetary Science, University of California Berkeley, 307 McCone Hall, Berkeley, CA 94710.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Druhan
authors.affiliation: Department of Radiology & Biomedical Imaging, University of California, San Francisco, 505 Parnassus Avenue, M-391 San Francisco, CA 94143.
authors.forename: David A
authors.initials: DA
authors.lastname: Saloner
authors.affiliation: Department of Radiotracer Development & Imaging Technology, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS55R0121, Berkeley, CA 94720.
authors.forename: Grant T
authors.initials: GT
authors.lastname: Gullberg
authors.affiliation: Department of Radiotracer Development & Imaging Technology, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS55R0121, Berkeley, CA 94720.
authors.forename: William W
authors.initials: WW
authors.lastname: Moses