Pulsed induction logging for determining conductivity and invaded zone properties
Patent
·
OSTI ID:6145155
An apparatus and method for measuring properties of earth formations surrounding a borehole and, particularly, conductivity properties of the formations and certain properties of the invaded zone of the formations. In accordance with one embodiment of the invention, a logging device, movable through the borehole, has a transmitter coil and first and second spaced receiver coils mounted thereon. A short pulse of electrical energy is applied to the transmitter coil. Signals are induced in the first and second receiver coils. A conductivity property of the surrounding formations is then determined as a function of the times of occurence of predetermined characteristics of the signals detected in the first and second receiver coils. In particular, the elapsed time between a zero-crossing of the signal induced in the first receiver coil and a zero-crossing of the signal induced in the second receiver coil is measured, and the conductivity of the surrounding formations is determined as being substantially proportional to said elapsed time. In another embodiment of the invention the polarities of the initial portions of the signals detected at a number of receiver locations are used in determining properties of the formation invaded zone, particularly its thickness and its conductivity as compared to the virgin formations.
- Assignee:
- Schlumberger Technology Corporation
- Patent Number(s):
- US 4481472
- OSTI ID:
- 6145155
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
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03 NATURAL GAS
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Geology
& Exploration
ELECTRIC COILS
ELECTRIC CONDUCTIVITY
ELECTRIC LOGGING
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
FUNCTIONS
PHYSICAL PROPERTIES
POWER SUPPLIES
PULSE TECHNIQUES
RECORDING SYSTEMS
RESERVOIR ROCK
RESPONSE FUNCTIONS
SIGNALS
TRANSMISSION
WELL LOGGING
WELL LOGGING EQUIPMENT
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
ELECTRIC COILS
ELECTRIC CONDUCTIVITY
ELECTRIC LOGGING
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
FUNCTIONS
PHYSICAL PROPERTIES
POWER SUPPLIES
PULSE TECHNIQUES
RECORDING SYSTEMS
RESERVOIR ROCK
RESPONSE FUNCTIONS
SIGNALS
TRANSMISSION
WELL LOGGING
WELL LOGGING EQUIPMENT