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US 8,009,511 B2Granted
Pressure waves decoupling with two transducers
AssigneeBaker Hughes Incorporated
InventorNabil Hentati
Life of this patent
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Abstract
A telemetry system for communication in a borehole uses two spaced-apart transducers. The outputs from the two transducers are filtered to decoupled tool signals traveling in opposite directions. One of the two signals may be it telemetry signal while other signal may be pump noise.
Claims12
A method of communicating through a fluid in a borehole between a first location and a second location, the method comprising:
- producing a first signal at the first location and a second signal at the second location, the first signal and the second signal traveling in opposite directions between a first position and a second position in the borehole;
- measuring a third signal at the first position indicative of the first and second signals;
- measuring a fourth signal at the second position indicative of the first and second signals;
- and
- using a result of filtering the third signal by a first filter with a result of filtering the fourth signal by a second filter and a third filter for estimating a value of the first signal at at least one frequency at a first output
- wherein the first filter, the second filter and the third filter are selected based upon a result at a second output of applying the first filter and the third filter to the third signal and applying the second filter to the fourth signal wherein the third filter has a phase shift substantially equal to π.
3 more elements
An apparatus for communicating through a fluid in a borehole between a first location and a second location, the apparatus comprising:
- a first signal source configured to produce a first signal at the first location and a second signal source configured to produce a second signal at the second location, the first signal and the second signal traveling in opposite directions between a first position and a second position in the borehole;
- a first transducer configured to produce a third signal at the first position indicative of the first and second signals;
- a second transducer configured to produce a fourth signal at the second position indicative of the first and second signals;
- and
- a processor configured to:
- use a result of filtering the third signal by a first filter with a result of filtering the fourth signal by a second filter and a third filter to estimate a value of the first signal at at least one frequency at a first output wherein the first filter the second filter and the third filter are selected based upon a result at a second output of applying the first filter and the third filter to the third signal and applying the second filter to the fourth signal wherein the third filter has a phase shift substantially equal to π.
3 more elements
Dependencies are inferred from the claim text.