Apparatus and method for sensing a pipe coupler within an oil well structure

Abstract

A system for sensing a pipe joint within a well structure bore comprises a body connectable in line with the well structure. The body has a central bore therethrough and includes a plurality of blind bores extending radially inwards from the outer surface. The system further includes at least one sleeve being locatable within one of the plurality of blind bores wherein each of the sleeves has a ma et located at an end thereof at least one sensor being locatable within one of the at least one sleeves. The at least one sensor is operable to output a signal representing the width of a metallic object located within the central bore. The system may further include a display operable to receive the output signal from the at least one sensor and to display an output to a user indicating the width of the metallic object within the central bore.

What is claimed is: 
     
         1 . A system for determining the outer diameter of a metallic object within a well structure, the system comprising:
 a spool connectable in line with said well structure, said spool having a central bore therethrough along a central axis corresponding to a central bore of said well structure and an outer surface, said spool including a plurality of blind bores extending radially inwards from said outer surface;   at least one ferromagnetic body being locatable within one of said plurality of blind bores, each of said ferromagnetic body having a magnet located at an end thereof; and   at least one sensor being associated with said at least one ferromagnetic body, said at least one sensor being operable to output a signal representing the diameter of said metallic object located within said central bore.   
     
     
         2 . The system of  claim 1  wherein said magnets comprise rare earth magnets. 
     
     
         3 . The system of  claim 1  wherein said magnets comprise electromagnets, 
     
     
         4 . The system of  claim 1  wherein said at least one ferromagnetic body comprises a sleeve. 
     
     
         5 . The system of  claim 1  wherein said at least one ferromagnetic body comprise a solid cylinder. 
     
     
         6 . The system of  claim 1  wherein said magnet is located at an end of said ferromagnetic body proximate to said central bore of said spool. 
     
     
         7 . The system of  claim 1  wherein said magnet is located at an end of said at least one ferromagnetic body distal to said central bore of said spool. 
     
     
         8 . The system of  claim 1  wherein said at least one sensor is located at an end of said ferromagnetic body proximate to said central bore of said spool. 
     
     
         9 . The system of  claim 4  wherein said at least one sensor is located within said sleeve. 
     
     
         10 . The system of  claim 1  wherein said spool includes a plurality of connection bores extending through said spool parallel to said central axis. 
     
     
         11 . The system of  claim 10  wherein said blind bores are located between said connection bores. 
     
     
         12 . The system of  claim 1  wherein said spool is formed of a substantially non-magnetic alloy. 
     
     
         13 . The system of  claim 12  wherein said spool is formed of a nickel-chromium based alloy. 
     
     
         14 . The system of  claim 1  wherein each of said at least one sensors comprise a ball effects sensor. 
     
     
         15 . The system of  claim 1  wherein at least one pair of blind bores are connected to each other by a bridging bar. 
     
     
         16 . The system of  claim 15  wherein a first pair of said blind bores are located on opposite sides of said spool. 
     
     
         17 . The system of  claim 15  wherein said bridging bar comprises a tubular member extending between said sleeves of said at least one pair of blind bores. 
     
     
         18 . The system of  claim 15  wherein said bridging bar comprises a solid member extending between said sleeves of said at least one pair of blind bores. 
     
     
         19 . The system of  claim 15  wherein said bridging bar is formed of a ferromagnetic material. 
     
     
         20 . The system of  claim 1  further comprising a display operable to receive said output signal from said at least one sensor and to display an output to a user indicating the width of said metallic object within said central bore.