Flow channeling and analysis of tracer tests in heterogeneous porous media
Flow and solute transport through porous medium with strongly varying hydraulic conductivity are studied by numerical simulations. The heterogeneity of the porous medium is defined by {sigma} and {lambda}{prime}, which are, respectively, the standard deviation of natural log of permeability values and its correlation range {lambda} divided by transport distance L. The development of flow channeling as a function of these two parameters is demonstrated. The results show that for large heterogeneities, the flow is highly channelized and solute is transported through a few fast paths, and the corresponding breakthrough curves show a high peak at very early times, much shorter than the mean residence time. This effect was studied for a converging radial flow, to simulate tracer tests in a fracture zone or contact-thickness aquifer. It is shown that {sigma}{sup 2}{lambda}{prime} is an appropriate parameter to characterize the tracer dispersion and breakthrough curves. These results are used to study tracer breakthrough data from field experiments performed with nonsorbing tracers. A new procedure is proposed to analyze the results. From the moments of the residence-time distribution represented by the breakthrough curves, the heterogeneity of the porous medium, as characterized by {sigma}{sup 2}{lambda}{prime} and the mean residence time t{sub o}, may be determined.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE. Assistant Secretary for Environmental Management. Office of Science and Technology; Swedish Nuclear Fuel and Waste Management Company, Japanese Nuclear Cycle Institute BG No.93-317 (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 836660
- Report Number(s):
- LBNL-49153; R&D Project: 830001; TRN: US200504%%224
- Journal Information:
- Water Resources Research, Vol. 30, Issue 5; Other Information: Submitted to Water Resources Research: Volume 30, No.5; Journal Publication Date: 05/1994; PBD: 3 Nov 2001
- Country of Publication:
- United States
- Language:
- English
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