Abstract: A method for monitoring a condition in at least one of a plurality of casing annuli in a subsea hydrocarbon production system having a wellhead housing mounted at the upper end of a well bore and a number of concentric well casings extending from the wellhead housing through the well bore, including an innermost casing through which a hydrocarbon fluid is produced. The plurality of casing annuli are defined between successive ones of the wellhead housing and the well casings. The method involves sensing at least a first condition at a first location in a first casing annulus, generating a first data signal at the first location which is indicative of the first condition, transmitting the first data signal from the first location to a second location either outside the wellhead housing or inside the innermost casing, receiving the first data signal at the second location; and transmitting the first data signal from the second location to a remote location at which the first condition may be monitored.

Abstract: A magnetic saturation apparatus for a wireless inductive power and/or data transfer system which comprises a magnetic field transmitter positioned on a first side of a barrier and a magnetic field receiver positioned on a second side of the barrier. The magnetic saturation apparatus includes a saturation magnet which is positioned on one side of the barrier and which in use generates a saturation flux in an adjacent saturation region of the barrier which is located at least partially between the transmitter and the receiver. The saturation flux effectively lowers the magnetic permeability of the saturation region and thereby inhibits the magnetic flux generated by the transmitter from shorting through the barrier and back into the transmitter. Thus, the saturation region facilitates the flow of magnetic flux from the transmitter into the receiver.

Abstract: A method for increasing the power transfer efficiency of a wireless induction power and/or data transfer system comprising a magnetic field transmitter which is positioned on a first side of a barrier and a magnetic field receiver which is positioned on a second side of the barrier opposite the first side comprises the steps of disposing at least one flux flow member in or adjacent the barrier at least partially between the transmitter and the receiver. The flux flow member comprises a magnetic permeability different from the magnetic permeability of the barrier. As a result, the flux flow member increases the amount of magnetic flux generated by the transmitter which is coupled through the barrier and into the receiver.

Abstract: A sensor apparatus comprises a first magnetic transducer which in use is positioned on a first side of a barrier and a second magnetic transducer which in use is positioned on a second side of the barrier opposite the first side. The second transducer comprises a magnetic or electrical property which is dependent upon a sensible condition on the second side of the barrier, such as the pressure or temperature on the second side of the barrier. In operation, the first transducer generates a first magnetic field which induces the second transducer to generate a second magnetic field that is dependent upon the magnetic or electrical property of the second transducer. The first transducer detects the second magnetic field and generates a signal which is representative of the sensible condition on the second side of the barrier.

Abstract: A method for monitoring a condition in at least one of a plurality of casing annuli in a subsea hydrocarbon production system having a wellhead housing mounted at the upper end of a well bore and a number of concentric well casings extending from the wellhead housing through the well bore, including an innermost casing through which a hydrocarbon fluid is produced. The plurality of casing annuli are defined between successive ones of the wellhead housing and the well casings. The method involves sensing at least a first condition at a first location in a first casing annulus, generating a first data signal at the first location which is indicative of the first condition, transmitting the first data signal from the first location to a second location either outside the wellhead housing or inside the innermost casing, receiving the first data signal at the second location; and transmitting the first data signal from the second location to a remote location at which the first condition may be monitored.

Abstract: A non-invasive wireless communication system for monitoring parameters existing within the casing annuli of a subsea hydrocarbon production system. The subsea hydrocarbon production system includes a wellhead housing mounted at the upper end of a well bore and a number of concentric well casings extending from the wellhead housing through the well bore, and the casing annuli are formed between successive ones of the wellhead housing and the well casings The monitoring system comprises an interrogation package which is adapted to wirelessly transmit and receive NFM and/or inductive signals and at least one sensing package which is located in one of the casing annuli and is adapted to wirelessly receive the signals from and transmit response signals to the interrogation package.

Abstract: A magnetic saturation apparatus for a wireless inductive power and/or data transfer system which comprises a magnetic field transmitter positioned on a first side of a barrier and a magnetic field receiver positioned on a second side of the barrier. The magnetic saturation apparatus includes a saturation magnet which is positioned on one side of the barrier and which in use generates a saturation flux in an adjacent saturation region of the barrier which is located at least partially between the transmitter and the receiver. The saturation flux effectively lowers the magnetic permeability of the saturation region and thereby inhibits the magnetic flux generated by the transmitter from shorting through the barrier and back into the transmitter. Thus, the saturation region facilitates the flow of magnetic flux from the transmitter into the receiver.

Abstract: A method for increasing the power transfer efficiency of a wireless induction power and/or data transfer system comprising a magnetic field transmitter which is positioned on a first side of a barrier and a magnetic field receiver which is positioned on a second side of the barrier opposite the first side comprises the steps of disposing at least one flux flow member in or adjacent the barrier at least partially between the transmitter and the receiver. The flux flow member comprises a magnetic permeability different from the magnetic permeability of the barrier. As a result, the flux flow member increases the amount of magnetic flux generated by the transmitter which is coupled through the barrier and into the receiver.

Abstract: A non-invasive wireless communication system for monitoring parameters existing within the casing annuli of a subsea hydrocarbon production system. The subsea hydrocarbon production system includes a wellhead housing mounted at the upper end of a well bore and a number of concentric well casings extending from the wellhead housing through the well bore, and the casing annuli are formed between successive ones of the wellhead housing and the well casings The monitoring system comprises an interrogation package which is adapted to wirelessly transmit and receive NFM and/or inductive signals and at least one sensing package which is located in one of the casing annuli and is adapted to wirelessly receive the signals from and transmit response signals to the interrogation package.

Abstract: A sensor apparatus comprises a first magnetic transducer which in use is positioned on a first side of a barrier and a second magnetic transducer which in use is positioned on a second side of the barrier opposite the first side. The second transducer comprises a magnetic or electrical property which is dependent upon a sensible condition on the second side of the barrier, such as the pressure or temperature on the second side of the barrier. In operation, the first transducer generates a first magnetic field which induces the second transducer to generate a second magnetic field that is dependent upon the magnetic or electrical property of the second transducer. The first transducer detects the second magnetic field and generates a signal which is representative of the sensible condition on the second side of the barrier.

Abstract: Described is a device for generating an acoustic signal in an electrically conductive medium such as salt water. The device of the present invention has a broadband frequency response and supports high bandwidth data transmission. Reliability is improved in comparison to conventional underwater acoustic transmitters as the device includes no moving components. In one embodiment, the device includes a parallel and alternating arrangement of electrodes and magnets. Neighboring electrodes have different voltages and neighboring magnets have opposite pole configurations such that the magnetic fields overlap the currents between the electrodes in the medium. The currents or the magnetic fields are modulated according to a data signal to generate an acoustic signal in the medium.

Abstract: A wireless magnetic through-hull communications apparatus and method which permit higher data-rate communications through materials than presently available using acoustic techniques is described. A signal source on one side of a barrier is directed into a coil driver which generates an amplified, modulated signal responsive thereto. The resulting signal is used to drive a transmitter coil which generates a time-varying magnetic field that penetrates the barrier as well as any gaps comprising water, air or other material between the barrier and the transmitter coil. On the other side of the barrier, and perhaps through additional gaps comprising water, air or other material, a receiver coil detects the time-varying magnetic field. This signal may be amplified and then digitized by a signal processor. The signal processor may then communicate with a data processing and/or display unit, another sensor or some other device.