Electronic measurement apparatus movable in a cased borehole and compensating for casing resistance differences
- (Bothell, WA)
Methods of operation of an apparatus having at least two pairs of voltage measurement electrodes vertically disposed in a cased well to measure the resistivity of adjacent geological formations from inside the cased well. During stationary measurements with the apparatus at a fixed vertical depth within the cased well, the invention herein discloses methods of operation which include a measurement step and subsequent first and second compensation steps respectively resulting in improved accuracy of measurement. The invention also discloses multiple frequency methods of operation resulting in improved accuracy of measurement while the apparatus is simultaneously moved vertically in the cased well. The multiple frequency methods of operation disclose a first A.C. current having a first frequency that is conducted from the casing into formation and a second A.C. current having a second frequency that is conducted along the casing. The multiple frequency methods of operation simultaneously provide the measurement step and two compensation steps necessary to acquire accurate results while the apparatus is moved vertically in the cased well.
- Research Organization:
- ParaMagnetic Logging, Inc. (Woodinville, WA)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG22-88BC14243
- Assignee:
- ParaMagnetic Logging, Inc. (Woodinville, WA)
- Patent Number(s):
- US 5075626
- Application Number:
- 07/434,886
- OSTI ID:
- 868103
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
measurement
apparatus
movable
cased
borehole
compensating
casing
resistance
differences
methods
operation
pairs
voltage
electrodes
vertically
disposed
measure
resistivity
adjacent
geological
formations
inside
stationary
measurements
fixed
vertical
depth
discloses
step
subsequent
compensation
steps
respectively
resulting
improved
accuracy
multiple
frequency
simultaneously
moved
disclose
current
conducted
formation
provide
acquire
accurate
results
moved vertically
compensation steps
measurement apparatus
vertically disposed
voltage measurement
measurement electrodes
geological formations
adjacent geological
geological formation
multiple frequency
simultaneously provide
cased borehole
casing resistance
improved accuracy
frequency methods
operation result
discloses methods
fixed vertical
electronic measurement
electrodes vertically
cased bore
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