Down-Hole Swivel Sub

Abstract

The present disclosure relates to a down-hole swivel sub ( 10 ) for connection in a work-string between a work-string and a down-hole apparatus, the sub comprising a first substantially cylindrical body ( 12 ) with a sleeve portion ( 22 ), a second substantially cylindrical body ( 28 ) being partially located within the sleeve portion ( 22 ) and the bodies being arranged to rotate relative to each other; and a clutch ( 90 ) disposed between said first and second substantially tubular bodies.

1 . A down-hole swivel sub for connection in a work-string between a work-string and a down-hole apparatus, the sub comprising a first substantially cylindrical body with a sleeve portion, a second substantially cylindrical body being partially located within the sleeve portion and the bodies being arranged to rotate relative to each other; and a clutch disposed between said first and second substantially tubular bodies. 
     
     
         2 . A down-hole swivel sub according to  claim 1  wherein the clutch includes a viscous coupling. 
     
     
         3 . A down-hole swivel sub according to  claim 1  wherein the clutch is a Hele-Shaw clutch. 
     
     
         4 . A down-hole swivel sub according to any preceding claim wherein the clutch is controlled by a control device. 
     
     
         5 . A down-hole swivel sub according to  claim 4  wherein the control device is actuated by a control signal. 
     
     
         6 . A down-hole swivel sub according to  claim 5  wherein the control signal is selected from the group comprising a pressure differential, a flow pulse, electrical, magnetic and a flow rate. 
     
     
         7 . A down-hole swivel sub according to  claim 1  wherein the clutch is actuated passively. 
     
     
         8 . A down-hole swivel sub according to  claim 1  wherein the first or second substantially cylindrical bodies are adapted to be attachable to a drill-string or work-string. 
     
     
         9 . A down-hole swivel sub according to  claim 1  wherein the first or second substantially cylindrical bodies are adapted to attach within a drill-string or work-string. 
     
     
         10 . A drill-string or work-string for use in a wellbore including at least one apparatus according to  claim 1 . 
     
     
         11 . An oil-rig comprising at least one apparatus according to  claim 1 . 
     
     
         12 . A method of running a downhole apparatus into a well-bore including the step of fitting an apparatus according to  claim 1 . 
     
     
         13 . A method of adapting a drill-string or work-string for use in a wellbore comprising the step of fitting a clutch between two independently rotatable sections of said drill-string or work-string.