Downhole signal coupling system

Abstract

A signal coupling system for data and/or power signalling in tubing within a hydrocarbon extraction well. First and second transceivers are arranged with primary and secondary loops lying orthogonal to the ends of the transceivers. The transceivers can be narrower for access downhole. Each loop is housed in a semi-cylindrical housing with a planar face, so providing a cylindrical body when oppositely arranged for the transfer of electromagnetic radiation therebetween. Guiding surfaces are also provided on the housing to assist in bring the coupling system together downhole. The present invention provides reliable real-time data from any location within the wellbore and improves reservoir management, well planning and resource exploitation.

1 . A signal coupling system for the transfer of data and/or power signals in tubing, the system comprising:
 a first conducting cable having a first transceiver at an end thereof;   said first transceiver sized to locate within said tubing and having a primary loop arranged at a first end thereof with a first plane enclosed by said primary loop being arranged substantially orthogonal to said first end and parallel to an axis of said tubing;   a second conducting cable having a second transceiver at an end thereof;   said second transceiver sized to locate within said tubing and having a secondary loop arranged at a second end thereof with a second plane enclosed by said secondary loop being arranged substantially orthogonal to said second end and parallel to an axis of said tubing;   said transceivers arranged oppositely with said first and said second ends overlapping such that said first plane and said second plane are in substantially parallel alignment to facilitate electromagnetic coupling therebetween.   
     
     
         2 . A signal coupling system according to  claim 1  wherein said primary and said secondary loop are directly opposed to maximise the electromagnetic coupling. 
     
     
         3 . A signal coupling system according to  claim 1  wherein said first and second ends are semi-cylindrical housings in which are located said primary and said secondary loops respectively, each housing having a first and second face respectively and said first and second faces being in substantially parallel alignment with said primary and said secondary loops respectively. 
     
     
         4 . A signal coupling system according to  claim 2  wherein said first and second faces are arranged oppositely to provide a substantially cylindrical coupling member. 
     
     
         5 . A signal coupling system according to  claim 4  wherein said first and second transceivers are substantially cylindrical members such that the system has a substantially cylindrical body. 
     
     
         6 . A signal coupling system according to  claim 5  wherein a ledge formed at a junction of said cylindrical member and said semi-cylindrical housing provides a guide surface. 
     
     
         7 . A signal coupling system according to  claim 6  wherein a front surface at a distal end of said cylindrical housing is shaped to mate with said guide surface. 
     
     
         8 . A signal coupling system according to  claim 7  wherein said front surface and said guide surface are arranged at an angle with respect to said first face. 
     
     
         9 . A signal coupling system according to  claim 5  wherein said substantially cylindrical body is coaxial to said axis of said tubing. 
     
     
         10 . A system coupling system according to  claim 5  wherein a diameter of said cylindrical body is less than half of a diameter of said tubing. 
     
     
         11 . A signal coupling system according to  claim 1  wherein the system includes a sensor for generating data to be transmitted through said cables. 
     
     
         12 . A signal coupling system according to  claim 1  wherein said tubing is production tubing located in a wellbore. 
     
     
         13 . A signal coupling system according to  claim 1  wherein said tubing is casing located in a wellbore. 
     
     
         14 . A signal coupling system according to  claim 1  wherein said tubing is a tubing string located in a wellbore. 
     
     
         15 . A method of data transfer in a wellbore, comprising the steps of:
 (a) locating a sensor in said wellbore;   (b) providing a signal coupling system including:   a first conducting cable having a first transceiver at an end thereof;   said first transceiver sized to locate within tubing in said wellbore and having a primary loop arranged at a first end thereof with a first plane enclosed by said primary loop being arranged substantially orthogonal to said first end and parallel to an axis of said tubing;   a second conducting cable having a second transceiver at an end thereof;   said second transceiver sized to locate within said tubing and having a secondary loop arranged at a second end thereof with a second plane enclosed by said secondary loop being arranged substantially orthogonal to said second end and parallel to an axis of said tubing;   (c) connecting said second conducting cable to said sensor and arranging said second transceiver in said tubing;   (d) running said first transceiver into the wellbore;   (e) aligning said transceivers to be arranged oppositely with said first and said second ends overlapping such that said first plane and said second plane are in substantially parallel alignment to facilitate electromagnetic coupling therebetween; and   (f) transmitting data from the sensor between the transceivers and up said first cable to a control command centre.   
     
     
         16 . A method according to  claim 15  wherein the method includes the step of transferring power down said first cable between said transceivers and to said sensor.