Patent ID: 6135202
Filing Date: 2000-10-24
Classification: E21B

Abstract:
Apparatus for injecting jointed tubulars into a wellbore or removing jointed tubulars therefrom comprising:a tubing injector positioned above said wellbore;a lift sub disposed in said tubing injector, said lift sub having an upper end and a lower end, said tubing injector having a pair of spaced-apart conveyor members for engaging said lift sub, and having a drive means for driving said conveyor members to move said lift sub upwardly and downwardly to inject or withdraw said jointed tubulars, said drive means being switchable between an operating position wherein said conveyor members move said lift sub and a stop position wherein said conveyor members stop said lift sub;connecting means attached to said lower end of said lift sub for connecting said lift sub to said jointed tubulars;an upper shoulder defined on said lift sub, said upper shoulder being positioned above said conveyor members;a lower shoulder defined on said lift sub, said lower shoulder being positioned below said conveyor members;an upper limit switch positioned above said conveyor members, said upper limit switch being operably associated with said drive means and engagable with said upper shoulder, wherein said drive means automatically moves to said stop position when said upper shoulder engages said upper limit switch thereby stopping downward movement of said lift sub; anda lower limit switch positioned below said conveyor members, said lower limit switch being operably associated with said drive means and engagable with said lower shoulder, wherein said drive means automatically moves to said stop position when said lower shoulder engages said lower limit switch, thereby stopping upward movement of said lift sub.