A ground fault immune power and data delivery system for downhole sensors is connected to a downhole motor via a three-phase power cable. An AC power supply and sensor data module are electrically connected to one of two conductors (phases) at a time selected from the three conductors (phases) to provide power and data signals to the downhole sensors. If a ground fault is detected on one of the two connected phases, an isolation module isolates the grounded phase and switches to the ungrounded connected phase to continue transmitting power and data signals. A frequency of AC power supply, data communication frequencies and a switching frequency of a drive controlling the downhole motor are orthogonal to each other in order to mitigate interference. Surface-to-downhole communication can occur by adjusting voltage, frequency and/or phase of AC power supply controlled by a processor.

A method includes receiving a request to supply power of a first type to a toolstring. The toolstring includes a first tool that operates using the power of the first type and a second tool that operates using power of a second type. The method also includes receiving an indication of a relay configuration relating to relay positions of relays of a switching circuit in the toolstring. The relay configuration enables the switching circuit to selectively supply the power of the first type or the power of the second type to the toolstring via a switching communication system. The method further includes, when the relay configuration does not enable the switching circuit to supply the power of the first type, sending a first command to the switching communication system to change the relay configuration to enable the switching circuit to supply the power of the first type.

An inspection apparatus for use in wellbores in the oil and gas industries relates in general to the field of transmission of data between downhole module in a wellbore and a controlling module at the surface. The invention provides a method and apparatus for determining analogue filter parameters for an analogue front end comprising a plurality of filter stages receiving signals from a telemetry module, by repeating the steps of; receiving a signal of a known frequency and processing said signal by determining the magnitude of the frequency of the received signal until a plurality of signals have been received and processed; calculating an optimum set of filter parameters in dependence upon the measured frequency magnitudes and a predefined set of filter stage frequency responses.

A ground fault immune power and data delivery system for downhole sensors is connected to a downhole motor via a three-phase power cable. An AC power supply and sensor data module are electrically connected to one of two conductors (phases) at a time selected from the three conductors (phases) to provide power and data signals to the downhole sensors. If a ground fault is detected on one of the two connected phases, an isolation module isolates the grounded phase and switches to the ungrounded connected phase to continue transmitting power and data signals. A frequency of AC power supply, data communication frequencies and a switching frequency of a drive controlling the downhole motor are orthogonal to each other in order to mitigate interference. Surface-to-downhole communication can occur by adjusting voltage, frequency and/or phase of AC power supply controlled by a processor.

A downhole system has a plurality of telemetry systems and a control system configured to obtain information from one or more sensors and transmit that information on one or more of the plurality of telemetry systems. The configuration of a controller may be changed so as to change which information is transmitted on a given telemetry system and how the information is to be transmitted on the given telemetry system.

A method for transmitting data in a frequency selective communication channel in provided. The method comprises: parsing data to be transmitted into a plurality of data fields; assigning the data from each data field into a corresponding one of a plurality of sub-channels; modulating the data from each of the plurality of sub-channels into a corresponding one of a plurality of sub-bands, the plurality of sub-bands having spaced apart center frequencies; and concurrently transmitting the data from the plurality of sub-bands onto the channel.

An electronic device for deployment in a remote location such as a well-bore comprises two main device terminals for connection to a remote power supply and communication assembly via two electrical couplings; a power storage arrangement (C1) having two power input terminals; a device communication arrangement having two device communication terminals; a device switching arrangement (S2) for selectively connecting each of the two power input terminals or each of the two device communication terminals to a respective one of the main device terminals; and a device controller for controlling the operation of the switching arrangement. A power supply and communication assembly is also provided and arranged to be coupled to one or more of the devices.

The present invention relates to inspection apparatus for use in wellbores in the oil and gas industries. In particular the invention relates in general to the field of transmission of data between downhole module in a wellbore and a controlling module at the surface. The invention provides a method and apparatus for determining analog filter parameters for an analog front end comprising a plurality of filter stages receiving signals from a telemetry module, by repeating the steps of; receiving a signal of a known frequency and processing said signal by determining the magnitude of the frequency of the received signal until a plurality of signals have been received and processed; calculating an optimum set of filter parameters in dependence upon the measured frequency magnitudes and a predefined set of filter stage frequency responses.

A downhole system has a plurality of telemetry systems and a control system configured to obtain information from one or more sensors and transmit that information on one or more of the plurality of telemetry systems. The configuration of a controller may be changed so as to change which information is transmitted on a given telemetry system and how the information is to be transmitted on the given telemetry system.

A ground fault immune power and data delivery system for downhole sensors is connected to a downhole motor via a three-phase power cable. An AC power supply and sensor data module are connected to only two of the three phases to provide power and data signals to the sensors. During normal operation, power and data signals are transmitted over only one of the two connected phases. If a ground fault is detected on the third unconnected phase, power and data signals continue to transmit over the connected phase. If a ground fault is detected on one of the two connected phases, an isolation module isolates the grounded phase and switches to the ungrounded connected phase to continue transmitting power and data signals. If two of the phases are grounded, the motor shuts off; however, power and data signals may continue to transmit over an ungrounded connected phase.