05592438 is referenced by 66 patents and cites 55 patents.

A transducer is described especially for use in providing acoustic transmission in a borehole. The transducer includes a multiple number of magnetic circuit gaps and electrical windings that have been found to provide the power necessary for acoustic operation in a borehole while still meeting the stringent dimensional criteria necessitated by boreholes. Various embodiments conforming to the design are described. Moreover, the invention includes transition and reflector sections, as well as a directional coupler and resonator arrangement particularly adapted for borehole acoustic communication.

An acoustic communication system is described especially designed for use in providing acoustic transmission of information in a borehole. The communication system comprises a surface transceiver and at least one downhole transceiver. The surface transceiver operates in conjunction with a host computer that sends commands to the downhole transceiver. Subsequently, the downhole transceiver transmits encoded data from subsurface, borehole sensors to the surface transceiver. The preferred embodiment uses Minimum Shift Keying (MSK) modulation for both transmitting commands to the downhole unit and for transmitting data to the surface transceiver. To facilitate operation of a coherent communication system in the inhospitable environment of a borehole, the acoustic channel is characterized to enable the system to choose the best possible frequency and bandwidth for communication transmission. Additionally, the system achieves synchronous operation by transmitting synchronization signals between the downhole transceiver and the surface transceiver prior to the units exchanging commands and data.

Title
Method and apparatus for communicating data in a wellbore and for detecting the influx of gas
Application Number
715364
Publication Number
5592438
Application Date
August 18, 1993
Publication Date
January 7, 1997
Inventor
Steven C Owens
Katy
TX, US
Frank L Gibbons
Houston
TX, US
James V Leggett III
Houston
TX, US
Ashok Patel
San Jose
CA, US
Louis H Rorden
Los Altos
CA, US
Agent
Melvin A Hunn
Assignee
Baker Hughes Incorporated
TX, US
IPC
H04L 27/22
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