Digital induction logging tool including means for measuring phase quadrature components in a phase sensitive detector
A digital induction resistivity logging system is disclosed for digitally measuring in one phase sensitive detector both the in-phase (R) and quadrature (X) phase components in a receiver signal generated in response to eddy currents flowing in the earth's sub-surface formations. The induction logging system includes a central processing unit (CPU) located at the surface for receiving digital signals from a digital induction logging tool located downhole, and for processing the received data. The digital induction tool includes a digital sinewave generator for generating a highly phase stable, low distortion transmitter signal the frequency of which is selectable from among at least two transmitter frequencies. Automatic phase compensation is included to dynamically compensate for both static and temperature dependent phase shift errors introduced by circuits of the tool involved in the component measurements. A floating point analog-to-digital convertor capable of handling the wide dynamic range in the detected phase component signals is provided to convert the phase detector output into digital samples for use by the CPU.
- Assignee:
- Schlumberger Technology Corp.
- Patent Number(s):
- US 4455529
- OSTI ID:
- 6610384
- Resource Relation:
- Patent File Date: Filed date 8 Jun 1981; Other Information: PAT-APPL-271278
- Country of Publication:
- United States
- Language:
- English
Similar Records
The two-loop variable-spaced induction logging tool for containment applications: Design and field results
Computer-based system for acquisition of nuclear well log data
Related Subjects
03 NATURAL GAS
58 GEOSCIENCES
INDUCTION LOGGING
DATA PROCESSING
NATURAL GAS WELLS
DESIGN
OIL WELLS
WELL LOGGING EQUIPMENT
ANALOG-TO-DIGITAL CONVERTERS
DIGITAL SYSTEMS
EDDY CURRENTS
ELECTRIC CONDUCTIVITY
ERRORS
PHASE SHIFT
RESERVOIR ROCK
SIGNALS
CURRENTS
ELECTRIC CURRENTS
ELECTRIC LOGGING
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
PHYSICAL PROPERTIES
PROCESSING
WELL LOGGING
WELLS
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration
580203 - Geophysics- Geophysical Survey Methods- (1980-1989)