Patents by Inventor Thomas J. Calvert

Thomas J. Calvert has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4355310
    Abstract: A communication system capable of continuously exchanging digital information in a well logging installation between apparatus arranged on the earth's surface and apparatus arranged in an earth borehole, interconnected by a cable. Both the surface apparatus and the downhole apparatus include a controller and a modem for sending digital command messages downhole and digital data messages uphole. The downhole apparatus also includes one or more tools which are coupled in parallel to the downhole controller via a bi-directional bus. Each tool has a universal (identical) interface adapted to recognize a specific address unique to itself and a universal address common to all interfaces. A command message with a universal address may activate all of the tools in a "free-running" mode to transmit a predetermined quantity of data in a predetermined sequence.
    Type: Grant
    Filed: August 6, 1979
    Date of Patent: October 19, 1982
    Assignee: Schlumberger Technology Corporation
    Inventors: Antoine Belaigues, Alain Paumard, Yves Durand, Thomas J. Calvert
  • Patent number: 3973181
    Abstract: A method and apparatus for investigating earth formations traversed by the borehole containing an electrically nonconductive fluid in which a system of pad-mounted electrodes are arranged laterally around a well tool. A high frequency oscillator is coupled to the electrodes through a selectively variable capacitor. As the apparatus is passed through the borehole, the high frequency current produced by the oscillator capacitively couples the electrodes to the formation and provides a measure of the electrical conductivity or resistivity of the earth formation.
    Type: Grant
    Filed: December 19, 1974
    Date of Patent: August 3, 1976
    Assignee: Schlumberger Technology Corporation
    Inventor: Thomas J. Calvert