Acoustic Communications Network with Frequency Diversification
AssigneeSchlumberger Technology Corporation
InventorArnaud Croux
Life of this patent
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Abstract
An acoustic communications network includes acoustic modems that exchange messages on an acoustic communications medium, such as tubing deployed in a wellbore. The acoustic communications medium is characterized by an acoustic transfer function having a plurality of passbands and a plurality of stopbands. The messages are communicated by encoding the message into a plurality of symbols representing the message and distributing the plurality of symbols across a bandwidth of a wideband acoustic signal that spans at least one passband and at least one stopband of the acoustic transfer function.
Claims20
A method of communicating in a borehole, comprising:
- transmitting a message via an acoustic communications medium between acoustic modems deployed in the borehole, the acoustic communications medium characterized by an acoustic transfer function having a plurality of passbands and a plurality of stopbands, wherein transmitting includes:
- encoding the message into a plurality of symbols representing the message;
- and
- distributing the plurality of symbols over a bandwidth of a wideband acoustic signal, wherein the bandwidth spans at least one passband and at least one stopband of the acoustic transfer function;
- and
- receiving and processing the wideband acoustic signal to recover the message from the plurality of symbols distributed over the bandwidth.
A method of transmitting messages in an acoustic communications network, comprising:
- transmitting a first message in a first wideband acoustic signal from a first acoustic modem in a network of acoustic modems deployed along an acoustic transmission medium, the message being addressed to a second acoustic modem and containing information to be re-transmitted by the second acoustic modem;
- determining, by a third acoustic modem, whether the second modem has received the first message;
- and, if not
- transmitting, by the third acoustic modem, a second message containing the information that was to be re-transmitted by the second acoustic modem.
A system for performing a downhole operation in a wellbore, comprising:
- a control and telemetry system located at a surface to control and monitor a downhole operation;
- downhole equipment located in the wellbore to observe a parameter of interest associated with the downhole operation;
- first and second acoustic modems coupled to an acoustic transmission medium at respective locations extending between the control and telemetry system and the downhole equipment, wherein the acoustic transmission medium has an acoustic frequency response comprising passbands and stopbands,
- wherein in response to receipt of a message directed to the downhole equipment, the first acoustic modem generates information representing the message, distributes the information across a bandwidth that spans at least one passband and at least one stopband of the acoustic frequency response to generate a first wideband signal, and acoustically transmits the first wideband signal to the second acoustic modem on the acoustic transmission medium.
Dependencies are inferred from the claim text.