Abstract: An apparatus for detecting an electromagnetic signal originating in a wellbore includes an antenna comprising a pair of spaced apart electrodes in the ground spaced apart by a first distance having a midpoint at a second distance from the wellbore. The system includes at least one of a shielded electrical cable connecting each electrode to an input of a detector circuit, wherein the shielding is connected to produce common mode noise rejection; b) a second spaced apart electrode pair antenna spaced apart by one half the first distance and having a midpoint spaced ?2/2 times the second distance from the surface of the wellbore, c) a second electrode pair antenna having a common midpoint with and being orthogonal to the at least one electric dipole antenna; and d) wherein the at least one electric dipole antenna is disposed in a second wellbore, the second wellbore having substantially no electrically conductive pipe therein.

Abstract: An electromagnetic (EM) telemetry system includes an EM transmitter configured to transmit EM signals downhole and multiple sensors each configured to communicate with the EM transmitter and with another of the multiple sensors. Each sensor is placed a distance from another sensor along a length of a wellbore in the EM telemetry system. The EM telemetry system also includes a processor configured to select two or more sensors of the multiple sensors based on a signal to noise ratio (SNR) of an EM signal received from the two or more selected sensors, a depth of the EM transmitter, or both.

Abstract: A method for conducting survey measurements in a ranging operation between a first well and a second well include generating an electromagnetic field in a downhole location in the first well and scanning for the electromagnetic field in a downhole location in the second well. When at least one characteristic of the electromagnetic field is detected, the method includes automatically initiating survey measurements for a ranging operation without receiving a downlink command from surface.

Abstract: An apparatus for detecting an electromagnetic signal originating in a wellbore includes an antenna comprising a pair of spaced apart electrodes in the ground spaced apart by a first distance having a midpoint at a second distance from the wellbore. The system includes at least one of a shielded electrical cable connecting each electrode to an input of a detector circuit, wherein the shielding is connected to produce common mode noise rejection; b) a second spaced apart electrode pair antenna spaced apart by one half the first distance and having a midpoint spaced ?2/2 times the second distance from the surface of the wellbore, c) a second electrode pair antenna having a common midpoint with and being orthogonal to the at least one electric dipole antenna; and d) wherein the at least one electric dipole antenna is disposed in a second wellbore, the second wellbore having substantially no electrically conductive pipe therein.

Abstract: A method for conducting survey measurements in a ranging operation between a first well and a second well include generating an electromagnetic field in a downhole location in the first well and scanning for the electromagnetic field in a downhole location in the second well. When at least one characteristic of the electromagnetic field is detected, the method includes automatically initiating survey measurements for a ranging operation without receiving a downlink command from surface.

Abstract: A data retrieval device for communicating between a downhole location within a wellbore (16) and a surface location (22) in which a downhole to surface telemetry system is installed and adapted to communicate between a first telemetry module and a second telemetry module with the second telemetry module (18) positioned downhole and connected to a string (12) positioned within the wellbore (16). The data retrieval device is provided with a housing adapted to be positioned inside the string; a communication device supported by the housing; a connection port positioned on the housing and adapted to be connected to a line; and an electronic module supported by the housing. The electronic module is in communication with the communication device and is adapted to store and use at least an identification parameter of the first telemetry module to intercept a signal transmission addressed to the first telemetry module from the second telemetry module (18) via the communication device.

Abstract: A method and system are presented for transmitting data along tubing in a borehole, comprising generating an acoustic signal using a transmitter at a first location on the tubing, and receiving the acoustic signal at a receiver at a second location on the tubing. The method and system further comprise: (i) generating the acoustic signal at the transmitter at a first frequency and bit rate; (ii) receiving the acoustic signal at the first frequency at the receiver and attempting to synchronize the receiver at the first frequency, and (iiia) if the synchronization is successful, continuing to transmit the acoustic signal so as to pass the data from the transmitter to the receiver; or (iiib) if the synchronization is unsuccessful, adjusting the frequency and/or bit rate of the signal and repeating steps (i)-(iii) on the basis of the adjusted signal.

Abstract: Techniques involve determining the conductivity profile of a formation from a well between a surface location and a borehole location. The method involves placing a first sensor at the surface location, a second sensor located at the borehole location, obtaining a first signal by detecting Schumann resonances from the electric field occurring at the first location, obtaining a second signal by detecting Schumann resonances from the electric field occurring at the second location with the second sensor; and combining the first and the second signal to determine the conductivity profile of the formation between the first location and the second location.

Abstract: A method and system are presented for transmitting data along tubing in a borehole, comprising generating an acoustic signal using a transmitter at a first location on the tubing, and receiving the acoustic signal at a receiver at a second location on the tubing. The method and system further comprise: (i) generating the acoustic signal at the transmitter at a first frequency and bit rate; (ii) receiving the acoustic signal at the first frequency at the receiver and attempting to synchronize the receiver at the first frequency, and (iiia) if the synchronization is successful, continuing to transmit the acoustic signal so as to pass the data from the transmitter to the receiver; or (iiib) if the synchronization is unsuccessful, adjusting the frequency and/or bit rate of the signal and repeating steps (i)-(iii) on the basis of the adjusted signal.

Abstract: A method and system are presented for transmitting data along tubing in a borehole, comprising generating an acoustic signal using a transmitter at a first location on the tubing, and receiving the acoustic signal at a receiver at a second location on the tubing. The method and system further comprise: (i) generating the acoustic signal at the transmitter at a first frequency and bit rate; (ii) receiving the acoustic signal at the first frequency at the receiver and attempting to synchronize the receiver at the first frequency, and (iiia) if the synchronization is successful, continuing to transmit the acoustic signal so as to pass the data from the transmitter to the receiver; or (iiib) if the synchronization is unsuccessful, adjusting the frequency and/or bit rate of the signal and repeating steps (i)-(iii) on the basis of the adjusted signal.

Abstract: Techniques involve determining the conductivity profile of a formation from a well between a surface location and a borehole location. The method involves placing a first sensor at the surface location, a second sensor located at the borehole location, obtaining a first signal by detecting Schumann resonances from the electric field occurring at the first location, obtaining a second signal by detecting Schumann resonances from the electric field occurring at the second location with the second sensor; and combining the first and the second signal to determine the conductivity profile of the formation between the first location and the second location.

Abstract: A downhole electromagnetic telemetry unit for use with a tubing string (5) includes an insulated electrically conductive member (31) and a processing unit (15). The insulated electrically conductive member (31) is electrically coupled to the tubing string (5) at an upper measuring point (23) and a lower measuring point (25). The processing unit (15) is configured to process a voltage difference measured between the upper measuring point (23) and the lower measuring point (25) across the insulated electrically conductive member (31) and to derive therefrom a signal transmitted from a surface location (13).

Abstract: An EM antenna for location on a pipe (10) surrounded by a casing (12). The antenna has a power source (21) for injecting a current across a first insulated section (25) of the pipe (10) and an electrode (22) for conducting the current from the pipe (10) to the casing (12). There is also a second insulated section (23) of the pipe arranged to operate together with the electrode (22) and first insulated section (25) for directing a path flow of the current. Such antennas are described both in relation to repeater arrangements as well as land and sea applications.

Abstract: A data retrieval device for communicating between a downhole location within a wellbore (16) and a surface location (22) in which a downhole to surface telemetry system is installed and adapted to communicate between a first telemetry module and a second telemetry module with the second telemetry module (18) positioned downhole and connected to a string (12) positioned within the wellbore (16). The data retrieval device is provided with a housing adapted to be positioned inside the string; a communication device supported by the housing; a connection port positioned on the housing and adapted to be connected to a line; and an electronic module supported by the housing. The electronic module is in communication with the communication device and is adapted to store and use at least an identification parameter of the first telemetry module to intercept a signal transmission addressed to the first telemetry module from the second telemetry module (18) via the communication device.

Abstract: A downhole communication system and method is presented for communicating between a downhole location within a wellbore and a surface location. The system preferably comprises a first and second telemetry module, a downhole tool, and an interface electrically connecting the downhole tool to the first and second telemetry modules. The first telemetry module is connected to a string and positioned downhole within the wellbore, and configured to receive communication signals via acoustic propagation or low frequency electromagnetic transmission. The second telemetry module is connected to the string and positioned downhole within the wellbore, and configured to receive communication signals via fluid pressure pulse commands. The downhole tool is operatively connected to the string. And the interface is adapted to selectively relay digital communication signals between the downhole tool and at least one of the first and second telemetry modules.

Abstract: A system for transmitting data along a borehole, comprises a drill string; a bottom hole assembly connected to the drill string including a drilling motor powered by flow of fluid from the drill string, a drill bit connected below the drilling motor and arranged to be rotated by the motor, and at least one sensor being positioned between the drilling motor and the drill bit; a first telemetry system for transmitting data from a first location below the drilling motor to a second location above the drilling motor, the first telemetry system comprising a first transmitter at the first location configured to induce an acoustic signal for propagation along the BHA, and a first acoustic receiver at the second location arranged to receive the acoustic signal; and a second telemetry system comprising two or more transmission channels for transmitting data received by the first acoustic receiver from the second location back up the borehole.

Abstract: A method and system are presented for transmitting data along tubing in a borehole, comprising generating an acoustic signal using a transmitter at a first location on the tubing, and receiving the acoustic signal at a receiver at a second location on the tubing. The method and system further comprise: (i) generating the acoustic signal at the transmitter at a first frequency and bit rate; (ii) receiving the acoustic signal at the first frequency at the receiver and attempting to synchronise the receiver at the first frequency, and (iiia) if the synchronization is successful, continuing to transmit the acoustic signal so as to pass the data from the transmitter to the receiver; or (iiib) if the synchronization is unsuccessful, adjusting the frequency and/or bit rate of the signal and repeating steps (i)-(iii) on the basis of the adjusted signal.

Abstract: Apparatus and method for transmitting data in a borehole (10) between a downhole installation including one or more tools (20) (for example downhole testing tools) and a surface installation (62), wherein the downhole installation is connected to the surface installation by means of a tubular conduit (such as a drill string or production tubing 14)). The apparatus comprises: an acoustic modem (26) associated with each tool, the modem acting to convert tool signals such as electrical tool signals into acoustic signals; and a hub (90) forming part of the downhole installation to which the tools and tubular conduit are connected and comprising an acoustic receiver (74) and an electromagnetic transmitter (80).

Abstract: A downhole electromagnetic telemetry unit for use with a tubing string (5) includes an insulated electrically conductive member (31) and a processing unit (15). The insulated electrically conductive member (31) is electrically coupled to the tubing string (5) at an upper measuring point (23) and a lower measuring point (25). The processing unit (15) is configured to process a voltage difference measured between the upper measuring point (23) and the lower measuring point (25) across the insulated electrically conductive member (31) and to derive therefrom a signal transmitted from a surface location (13).

Abstract: An EM antenna for location on a pipe (10) surrounded by a casing (12). The antenna has a power source (21) for injecting a current across a first insulated section (25) of the pipe (10) and an electrode (22) for conducting the current from the pipe (10) to the casing (12). There is also a second insulated section (23) of the pipe arranged to operate together with the electrode (22) and first insulated section (25) for directing a path flow of the current. Such antennas are described both in relation to repeater arrangements as well as land and sea applications.