Measurement of core electrical parameters at ultrahigh and microwave frequencies
The Electromagnetic Propagation Tool (EPT) has demonstrated that the electrical conductivity and dielectric permittivity of rocks at microwave frequencies are different from those at low frequencies. These differences are helpful in determining the properties of the rocks and the fluids they contain and thus contribute to improved formation evaluation. Electrical parameters of rocks are found generally complex. A technique has been developed for measuring the complex dielectric permittivity, conductivity, and magnetic permeability over a range of frequencies in the ultrahigh frequency (UHF) and microwave frequency bands (100 MHz to 2.0 GHz). The sample core constitutes the dielectric of a coaxial transmission-line sample holder. With an S-parameter setup, two-port S-parameter measurements are made. The complex constituent parameters (epsilon', epsilon'', sigma, ..mu..) of the core samples then are computed from the S-parameters. Measurements on bulk water of various salinities demonstrate the salinity dependence of the dielectric constant (epsilon'/epsilon /SUB o/ ) of water at high salinities. The total measured loss is separated into a conductivity loss (sigma) and a dielectric loss (epsilon''/epsilon /SUB O/ ), since the frequency dependence of conductivity loss is well-known. Computed conductivity of bulk water shows little dispersion and is in good agreement with measured low-frequency (400-Hz) values.
- OSTI ID:
- 6112847
- Journal Information:
- J. Pet. Technol.; (United States), Journal Name: J. Pet. Technol.; (United States) Vol. 34:11; ISSN JPTJA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
DIELECTRIC PROPERTIES
ELECTRIC CONDUCTIVITY
ELECTRIC LOGGING
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELECTROMAGNETISM
FREQUENCY RANGE
HZ RANGE
MAGNETISM
MICROWAVE RADIATION
PARAMETRIC ANALYSIS
PHYSICAL PROPERTIES
RADIATIONS
RESISTIVITY LOGGING
ROCKS
WELL LOGGING