HR: 1330h
AN: H42F-1134    [PDF]
TI: Evolution of Fracture Permeability
AU: * Ebel, K A
EM: kebel@ner.com
AF: New England Research, Inc., 331 Olcott Drive Suite L1, White River Junction, VT 05001 United States
AU: Brown, S R
EM: sbrown@ner.com
AF: New England Research, Inc., 331 Olcott Drive Suite L1, White River Junction, VT 05001 United States
AB: Pore fluid flow and fluid composition within fractured rocks is a subject of primary importance to fields including hazardous waste isolation and remediation, oil and gas production, geothermal energy extraction, and formation of vein fillings and ore deposits. For these reasons, considerable effort has been placed on characterization and modeling of flow in fractures and fracture systems. We are investigating the complex active chemical interaction between pore fluid and fractures that causes the fluid composition and topography of these systems to change over time. Our experimental model consists of CaSO4 samples pressed with a constant force against an inert textured fracture surface. Pore fluids ranging from unsaturated to supersaturated which are at a variety of flow rates are introduced to one end of the sample in order to actively alter the topography of the CaSO4 surface. Using a laser profiler, we are able to quantitatively monitor the changing surface topography over time as it relates to the measured sample permeability and calcium saturation of the pore fluid. These methods allow us to create and analyze many features seen in natural fractures, including high-flow dissolution channels, plateaus, and caverns formed from precipitate. In addition, the laser profile of the sample surface can be used to produce a map of aperture across the sample. Using this information, we have applied numerical modeling via finite difference and lattice Boltzmann methods to calculate pore fluid flow direction and magnitude over the entire sample surface. This research is part of an integrated program using quantitative observations of fractures and veins in drill core as well as quantitative and visual observations of flow and chemical dissolution and precipitation within replicas of rough-walled fractures in order to refine our models and work toward a predictive capability.
DE: 1815 Erosion and sedimentation
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1848 Networks
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: 2003 Fall Meeting