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US 8,542,553 B2Granted
Downhole sonic logging tool including irregularly spaced receivers
AssigneeSchlumberger Technology Corporation
InventorTsili Wang
Life of this patent
Estimating the term…
Abstract
A downhole acoustic measurement tool includes at least one transmitter longitudinally spaced apart from a non-uniformly spaced longitudinal array of acoustic receivers. The array has a non-uniform spacing such that a first spacing between a first pair of consecutive acoustic receivers in the array is not equal to a second spacing between a second pair of consecutive acoustic receivers in the array. Non-uniform spacing of the receivers in the array reduces aliasing when the received waveforms are processed, for example, to obtain semblance data.
Claims15
A downhole acoustic measurement tool, comprising:
- a downhole tool body;
- at least one acoustic transmitter deployed on the tool body, the transmitter configured to transmit an acoustic waveform into a subterranean borehole;
- an array of receivers deployed on an external surface of the tool body, the array including a plurality of longitudinally spaced apart acoustic receivers, the acoustic receivers being longitudinally spaced apart from the transmitter and configured to receive said transmitted acoustic waveform, the array having a non-uniform spacing such that a first spacing between a first pair of consecutive acoustic receivers in the array is not equal to a second spacing between a second pair of consecutive acoustic receivers in the array:
- and
- wherein the array comprises first and second longitudinally spaced subarrays, each of the subarrays including a plurality of said acoustic receivers, the acoustic receivers in each subarray being uniformly spaced, the first and second subarrays being spaced apart from one another by a distance that is less than a distance between consecutive ones of the acoustic receivers in either of the first and second subarrays.
2 more elements
A downhole acoustic measurement tool, comprising:
- a downhole tool body;
- at least one acoustic transmitter deployed on the tool body, the transmitter configured to transmit an acoustic waveform into a subterranean borehole;
- and
- an array of receivers deployed on an external surface of the tool body, the array including first and second subarrays;
- each of the first and second subarrays comprising a plurality of longitudinally spaced apart acoustic receivers, the acoustic receivers being longitudinally spaced apart from the transmitter and configured to receive said transmitted acoustic waveform;
- the first subarray having a first spacing between consecutive receivers, the second subarray having a second spacing between consecutive receivers, wherein the first spacing is not equal to the second spacing, and
- wherein the first and second subarrays are longitudinally spaced apart from one another by a third spacing, the third spacing being equal to one of the first and second spacings.
4 more elements
A downhole acoustic:
- measurement tool, comprising:
- a downhole tool body;
- at least one acoustic transmitter deployed on the tool body, the transmitter configured to transmit an acoustic waveform into a subterranean borehole;
- an array of receivers deployed on an external surface of the tool body, the array including first and second subarrays;
- each of the first and second subarrays including a plurality of longitudinally spaced apart acoustic receivers, the acoustic receivers being longitudinally spaced apart from the transmitter and configured to receive said transmitted acoustic waveform;
- and
- the first subarray having a first spacing between consecutive receivers, the second array having a second spacing between consecutive receivers, the first spacing being equal to the second spacing, and the second subarray being longitudinally spaced apart from the first array by a third spacing that differs from at least one of the first spacing and the second spacing.
4 more elements
A downhole acoustic measurement tool, comprising:
- a downhole tool body:
- at least one transmitter deployed on the tool body, the transmitter configured to transmit an acoustic waveform into a subterranean borehole;
- an array of receivers deployed on an external surface of the tool body, the array including first and second subarrays;
- each of the first and second subarrays including a plurality of longitudinally spaced apart acoustic receivers, the acoustic receivers being longitudinally spaced apart from the transmitter and configured to receive said transmitted acoustic waveform, the first and second subarrays having identical spacing between consecutive receivers;
- at least a portion of the second subarray being interleaved with at least a portion of the first subrrays so as to define an interarray distance that is less than one-half the spacing between consecutive receivers in the first array.
2 more elements
A downhole acoustic measurement tool, comprising:
- a downhole tool body;
- at least one acoustic transmitter deployed on the tool body, the transmitter configured to transmit an acoustic waveform into a subterranean borehole;
- an array of receivers deployed on an external surface of the tool body, the array including a plurality of longitudinally spaced apart acoustic receivers, the acoustic receivers being longitudinally spaced apart from the transmitter and configured to receive said transmitted acoustic waveform, the array having a non-uniform spacing such that a first spacing between a first pair of consecutive acoustic receivers in the array is not equal to a second spacing between a second pair of consecutive acoustic receivers in the array;
- and
- the array of receivers including first and second subarrays, the first and second subarrays being at least partially interleaved with one another.
2 more elements
Dependencies are inferred from the claim text.