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US 2004/0006428 A1Published application
System and method for determining formation slowness
AssigneeSchlumberger Technology Corporation
InventorsKAI HSU, DOMINIQUE DION
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Abstract
The invention provides techniques for calculating velocity from sonic signals with an improved signal to noise ratio, accuracy and certainty of result. Multichannel coherence measures are calculated from sonic transmitter signals and averaged to produce an average coherence measure. The formation slowness is determined from the averaged coherence measure.
Claims19
A system for sonic logging of an earth formation, comprising:
- a logging instrument adapted for disposal within a wellbore traversing the formation;
- at least one acoustic transmitter disposed on the logging instrument;
- at least one receiver adapted to detect acoustic signals disposed on the logging instrument;
- processor means adapted to process acoustic signals to determine a coherence measure from acoustic signals detected by the at least one receiver and associated with the at least one transmitter actuations;
- and
- processor means adapted to average the coherence measure for a plurality of the at least one transmitter actuations to determine a property of the formation.
3 more elements
A system for sonic logging of an earth formation, comprising:
- a logging instrument adapted for disposal within a wellbore traversing the formation;
- at least one acoustic transmitter disposed on the logging instrument;
- at least one receiver adapted to detect acoustic signals disposed on the logging instrument;
- processor means adapted to process acoustic signals without stacking said signals to determine a coherence measure from acoustic signals detected by the at least one receiver and associated with the at least one transmitter actuations;
- and
- processor means adapted to average the coherence measure for a plurality of the at least one transmitter actuations to determine a property of the formation.
3 more elements
A method for sonic logging of an earth formation, comprising:
- (a) repeatedly actuating an acoustic transmitter on a well logging instrument disposed in a wellbore traversing the formation;
- (b) detecting acoustic signals with at least one receiver disposed on the instrument;
- (c) determining a coherence measure from the detected acoustic signals associated with the at least one transmitter actuations;
- and
- (d) averaging the coherence measure for a plurality of the transmitter actuations to determine a property of the formation.
2 more elements
A method for sonic logging of an earth formation, comprising:
- (a) repeatedly actuating an acoustic transmitter on a well logging instrument disposed in a wellbore traversing the formation;
- (b) detecting acoustic signals with at least one receiver disposed on the instrument;
- (c) determining a coherence measure from the detected acoustic signals associated with the at least one transmitter actuations without stacking said signals;
- and
- (d) averaging the coherence measure for a plurality of the transmitter actuations to determine the slowness of the formation.
2 more elements
Dependencies are inferred from the claim text.