Some anomalous features of flow and solute transport arising from fracture aperture variability

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Water Resources Research; (USA)

DOI:https://doi.org/10.1029/WR026i010p02377· OSTI ID:5579359

Moreno, L; Neretnieks, I ^[1]; Tsang, Chinfu; Tsang, Yvonne ^[2]

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1. Royal Institute of Technology, Stockholm (Sweden)
2. Univ. of California, Berkeley (USA)

Model fractures with variable apertures are generated by a statistical method, and water flow and tracer transport in these fractures are calculated. Tracer injection and collection are simulated for parallel and convergent flow fields. The impact of the use of different injection flow rates and the different locations of injection and collection points are studied. The results show that the transport time, dispersion, and the so-called mass balance fracture aperture are very sensitive to the location of the injection point and the injection flow rate. These anomalous effects appear to be consistent with observations in several recent field experiments. The implications of the calculated results on the analysis of tracer tests are discussed. It is concluded that because of the stochastic nature of variable fracture apertures (and their permeabilities) a point tracer test in a fracture is not sufficient to characterize the properties of the fracture. Dispersivities and apertures calculated from different tracer tests in the same fracture may vary by orders of magnitude depending on the flow rate and the location of the injection. However, a line injection of tracer, averaged over a series of adjacent points, may avoid some of these problems.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5579359
• Journal Information: Water Resources Research; (USA), Journal Name: Water Resources Research; (USA) Vol. 26:10; ISSN 0043-1397; ISSN WRERA
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
152002* -- Geothermal Data & Theory-- Properties of Minerals & Rocks
APERTURES
FIELD TESTS
FLUID FLOW
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICS
HYDROLOGY
ISOTOPE APPLICATIONS
OPENINGS
PERMEABILITY
PHYSICAL PROPERTIES
SOLUTES
TESTING
TRACER TECHNIQUES