Cidra Corporation

Aps Technology, Inc.

Walter A Helm

Martin A Putnam

Michael A Davis

William Evans Turner

Robert N Brucato

David G Bellemore

Denis P Biglin, Jr

A tunable optical device has a compression tuned optical structure and a displacement sensor. The compression tuned optical structure responds to an optical signal, and further responds to a displacement sensor signal, for providing a compression tuned optical structure signal containing information about a change in an optical characteristic of the compression tuned optical structure, and for also further providing an excitation caused by a change in a displacement of the compression tuned optical structure. The displacement sensor responds to the excitation, for providing a displacement sensor signal containing information about the change in the displacement of the compression tuned optical structure. The compression tuned optical structure may be in the form of a dogbone structure that is an all-glass compression unit having wider end portions separated by a narrower intermediate portion. The displacement sensor includes a capacitance sensor affixed to the compression tuned optical structure for measuring a change in capacitance between two parallel and opposing plates that depends on a change in a gap or an area with respect to the two parallel and opposing plates.

Tunable optical structure featuring feedback control

A method and apparatus for communicating with a device downhole in a well, such as a bottom hole assembly in a drill string. Pressure pulses, such as those generated by the pistons of the mud pump, are transmitted through the drilling mud to a pressure pulsation sensor in the bottom hole assembly. The pressure pulsation sensor features a piezoceramic element that generates a varying voltage signal in response to the received pressure pulsations. The pressure pulsation sensor also has electronic components that allow it to analyze a characteristic of the pressure pulsations, such as their frequency. Based on its analysis of the pressure pulsations, the sensor can decipher a command from the surface, for example, that directs the steering of a steerable drill string, or that can determine whether the mud pumps are operating. If the mud pumps are not operating the sensor directs a microprocessor to reduce power to the bottom hole assembly electrical components, such as a measurement while drilling tool, thereby conserving battery power. The method and apparatus can also be used to control the operation of flow control valves in a multilateral well.

Method and apparatus for communicating with devices downhole in a well

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Farmington, CT, United States of America

Walter A Helm