Measurement and analysis of dissolution patterns in rock fractures

WATER RESOURCES RESEARCH, VOL. 38, NO. 2, 10.1029/2001WR000246, 2002

Peter Erik Dijk

Department of Environmental Sciences and Energy Research, Weizmann Institute of Science,
Rehovot, Israel

Now at School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA

Brian Berkowitz

Department of Environmental Sciences and Energy Research, Weizmann Institute of Science,
Rehovot, Israel

Yoseph Yechieli

Geological Survey of Israel,
Jerusalem, Israel

Abstract

[1] Nuclear magnetic resonance imaging (NMRI) is applied to noninvasively measure flow and dissolution patterns in natural, rough-walled, water-saturated halite fractures. Three-dimensional images of water density and flow velocity acquired with NMRI allow quantification of the developing fracture morphology and flow patterns. The flow patterns are correlated strongly to the local apertures and the large-scale wall roughness. The correlations of the dissolution patterns to the fracture morphology, flow patterns, and mineralogical composition of the rock matrix are a function of the overall dimensionless Damköhler number. At high Damköhler numbers the dissolution patterns are dominated by the flow structure. In addition, at high Damköhler numbers buoyancy (stratified flow) becomes important. In such cases the dissolution patterns also depend on the orientation and elevation of the fracture walls, resulting in preferential upward dissolution. At low Damköhler numbers the dissolution patterns depend mainly on the mineralogical composition of the rock matrix. These findings suggest that coupled flow and dissolution processes are much more complex and unpredictable than commonly assumed, even under simplified conditions.

Received 29 September 2000; revised 20 September 2001; accepted 20 September 2001; published 19 February 2002.

Keywords: rock, fracture, flow, transport, dissolution, nuclear magnetic resonance imaging.

Index Terms: 1010 Geochemistry: Chemical evolution; 1832 Hydrology: Groundwater transport; 5114 Physical Properties of Rocks: Permeability and porosity; 5139 Physical Properties of Rocks: Transport properties.

Citation: Dijk, P. E., B. Berkowitz, and Y. Yechieli, Measurement and analysis of dissolution patterns in rock fractures, Water Resour. Res., 38(2), 10.1029/2001WR000246, 2002.