Qinetiq Limited

Michael William Hopkins

Rajinder Singh

Lyn David Jones

Timothy Rupert Charles Jarman

Stuart John Eaton

Adrian Robert Bowles

A system for imaging material, typically in an underground scenario, comprising of a plurality of conductive electrodes supported on a conductive substrate positionable in an environment to be imaged, a signal generator connected to at least two of the electrodes, and a signal detector connected to at least two of the electrodes, and wherein an impedance compensator is arranged between each electrode and its substrate to counter parasitic impedance between the two. Typically the impedance compensator may be arranged to act as a negative capacitance, which may be approximately equal to any capacitance between the electrode and the substrate. An electrode may be a drive electrode coupled to a signal generator, or a detector electrode coupled to a detector, or may be reconfigurable to act as either one.

Resistivity imaging system with compensator for parasitic impedances between electrodes and their conductive substrates

A sensor system for the measurement of a physical parameter, such as temperature or pressure comprises a first, fixed module (), and a second module () positionable proximate to the first. The first module has a measurement coil () and a reference coil (), where the measurement coil forms part of an electrical circuit that is subject to variation by the physical parameter, and the reference coil forms part of a circuit not subject to the physical parameter being measured. The second module has a pair of reading coils (), each arranged to couple to respective measurement and reference coils, where the reading coils are connectable to signal generation and measurement equipment, and the system is arranged to measure electrical characteristics of the measurement and reference coils via the coupling. It has particular utility in harsh environments such as in wells, where the first module may be fixed, and the second module may be lowered adjacent the first. Measurements from the reference coil may be used to calibrate the measurements from the measurement coil. Further coils may be used to aid alignment of the two modules.

Sensor

Apparatus for the wireless transmission of data, and preferably also of power, across a space between a length of production tubing and a surrounding casing in a petrochemical well, includes a pair of inductively-coupled coils, a first of which is located on the exterior of the production tubing generally coaxially therewith, and the second of which is located on the interior of the casing generally coaxially therewith. This may be used in particular as part of a system for transmitting power and data to/from a sensor monitoring the pressure and/or other environmental conditions within the 'B' annulus B of a sub-sea well.

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Farnborough, United Kingdom

Michael William Hopkins