Abstract: An apparatus for measuring a pipe within a well structure comprises a tubular body extending between first and second ends and having an inner surface defining a passage therethrough and an outer surface formed of a non-magnetic alloy metal. The apparatus further comprises a pair of flanges each connected to one of the first or second ends of the tubular body having a passage therethrough corresponding to the passage of the tubular body, each of the pair of flanges being connectable inline with the well structure. The apparatus further comprises at least one sensor stack being locatable around an outside of the tubular body comprising a sensor adapted to measure magnetic field strength and at least one magnetic stack being locatable around the outside of the tubular body comprising at least one magnet.

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 magnet 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.