HR: 0830h
AN: H11G-0956    [PDF]
TI: Fully Determined Fluid Velocity Fields for Complex 2D Media with Multi-Scaled Heterogeneity.
AU: * Cassidy, R
EM: ri.cassidy@ulster.ac.uk
AF: Geophysics Research Group, University of Ulster, Coleraine, BT52 1SA Ireland
AU: McCloskey, J
EM: j.mccloskey@ulster.ac.uk
AF: Geophysics Research Group, University of Ulster, Coleraine, BT52 1SA Ireland
AU: Morrow, P
EM: pj.morrow@ulster.ac.uk
AF: School of Information and Software Engineering, University of Ulster, Coleraine, BT52 1SA Ireland
AB: Numerical schemes for fluid flow in complex rock geometries rely on comparison with existing empirical data for their validation. When available, these data are generally limited to non-unique, bulk measurements of properties such as hydraulic conductivity and permeability and are not adequate to fully validate complex numeric schemes. Here we describe an experimental system which has been developed to fully quantify velocity fields throughout synthetic two-dimensional heterogeneous media. We first create a digital image with the desired combination of matrix and fracture porosity, incorporating detail over several orders of magnitude. This image is then translated into a physical medium using either stereolithography or wire EDM machining. The result is a flow cell comprising two transparent plates with a thin section of material, identical to the digital image of the medium, between them. In order to observe and measure fluid velocity, the flow cell is integrated in a purpose built experimental rig and a controlled flow of fluid, seeded with neutrally dense micro-particles, is induced. Local velocities are then measured throughout the medium with a high-resolution digital particle image velocimetry system. Simultaneously fluid flow is simulated in these geometries using a variety of numerical schemes. Direct comparison is then made between measured and predicted velocity fields for geometries that include complex combinations of matrix and fracture flow, investigations of the effect of fracture roughness on the flow field and scaling laws in the region of the percolation threshold. Results and conclusions are presented.
UR: http://www.science.ulst.ac.uk/crg/geophys/research/nerc_fluids.htm
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1869 Stochastic processes
DE: 1894 Instruments and techniques
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: 2003 Fall Meeting