Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources
- (Bothell, WA)
Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation.
- Research Organization:
- ParaMagnetic Logging, Inc. (Bothell, WA)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- FG06-84ER13294; FG22-88BC14243
- Assignee:
- Para Magnetic Logging, Inc. (Woodinville, WA)
- Patent Number(s):
- US 5043669
- OSTI ID:
- 867956
- Country of Publication:
- United States
- Language:
- English
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Methods and apparatus for measurement of electronic properties of geological formations through borehole casing
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apparatus
measurement
resistivity
geological
formations
cased
presence
acoustic
magnetic
energy
sources
provided
measuring
acoustically
modulated
electronic
properties
cement
layers
adjacent
boreholes
current
passed
electrode
electrical
contact
interior
borehole
casing
surface
earth
voltage
electrodes
measure
various
thereon
differences
discrete
pairs
provide
leakage
conducted
formation
vicinity
simultaneously
subjecting
source
modulates
measured
providing
similarly
described
applied
field
allows
magnetically
acoustic source
measuring electrodes
energy sources
geological formations
electrical contact
magnetic field
energy source
voltage measuring
cased boreholes
electronic properties
applied magnetic
borehole casing
geological formation
leakage current
magnetic energy
voltage difference
modulated electron
cased borehole
casing measure
cement layers
modulated electronic
voltage differences
electrodes provide
allows measurement
current conducted
measuring electrode
layers adjacent
discrete pairs
cased bore
simultaneously subject
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