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Method and apparatus for logging a borehole

  • US 4,837,753 A
  • Filed: 04/10/1987
  • Issued: 06/06/1989
  • Est. Priority Date: 04/10/1987
  • Status: Expired due to Term
First Claim
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1. A method for generating a signal containing information relating to the state of a borehole, said method being of the type in which acoustic energy pulses are transmitted from the central portion of the borehole toward the borehole wall in a plurality of radial directions and at a plurality of different depths thereby generating reflected acoustic pulses from a reflecting boundary adjacent the borehole which are indicative of the condition of the reflecting boundary, said method comprising the steps of:

  • providing means in a downhole housing for substantially continuously rotating at a rate dependent upon a speed control signal supplied to said rotating means;

    providing a transducer assembly on said rotating means, said transducer assembly including means for generating such acoustic energy pulses and means for receiving such reflected acoustic pulses;

    generating in the housing a speed control signal for a selected controlled rate of substantially continuous rotation of the rotating means;

    providing the speed control signal to the rotating means;

    varying the rate of substantially continuous rotation of the rotating means while in the borehole; and

    generating and without interrupting scanning, varying the rate of generating periodic pulses firing signals for producing such acoustic energy pulses while in the borehole.

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