Dispersion in tracer flow in fractured geothermal systems

Journal Article · Fri Apr 01 04:00:00 UTC 1983 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL010i004p00289· OSTI ID:6103033

Horne, R N; Rodriguez, F

Interpretation of tracer tests is commonly based on the analysis of flow through a porous medium. In geothermal reservoirs however the principal permeability arises from fractures, and a porous medium approach is not applicable. The dispersion of tracer material flowing in a fracture is shown to be dominated by molecular diffusion across the fracture - a mechanism known as Taylor dispersion. For typical values of reservoir parameters, this transverse diffusion will obliterate any transverse tracer concentration gradients caused by the velocity profile across the fracture. The effective dispersivity is found to be a function of fracture aperture, mean flow velocity and molecular diffusivity, and is orders of magnitude greater than for porous medium flow. Typically Peclet numbers are anticipated to lie between orders 1 and 100, and field results confirm this range.

• OSTI ID: 6103033
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 10:4; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150906* -- Geothermal Engineering-- Reservoir Stimulation & Extraction Technology
152000 -- Geothermal Data & Theory
APERTURES
DIFFUSION
ENERGY SYSTEMS
FAILURES
FLOW RATE
FRACTURE PROPERTIES
FRACTURES
GEOTHERMAL SYSTEMS
HYDROTHERMAL SYSTEMS
ISOTOPE APPLICATIONS
MASS TRANSFER
MECHANICAL PROPERTIES
OPENINGS
POROSITY
TRACER TECHNIQUES