Injector for logging or intervention string

Abstract

A well logging- or well intervention string injector includes two adjacent motorized endless chains with gripper elements for bearing against the string. The gripping elements have an engagement packer against the string. The gripping elements run over the back supporting rollers carried by separate back supporting roller brackets. The back supporting roller brackets further bear against an elongated hydrostatic pressure equalizing cushion with hydraulic fluid. The pressure equalizing cushion bears against a back supporting rail.

1 . A well logging- or well intervention string injector comprising two adjacent motorized endless chains with gripper elements for bearing against said string,
 wherein said gripping elements have an engagement packer against said string,   wherein said gripping elements run over back supporting rollers carried by separate back supporting roller brackets,   wherein said back supporting roller brackets further bear against an elongated hydrostatic pressure equalizing cushion with hydraulic fluid, and   wherein further said pressure equalizing cushion bears against a back supporting rail.   
     
     
         2 . The injector according to  claim 1 , wherein said back supporting rail presses in the direction towards said string back supported by two or more springs. 
     
     
         3 . The injector according to  claim 2 , wherein two adjacent back supporting rails are arranged and mutual forced against each other by springs. 
     
     
         4 . The injector according to  claim 1 , wherein said pressure equalizing cushion comprises a flexible metallic hose. 
     
     
         5 . The injector according to  claim 1 , wherein the cross section of said pressure equalizing cushion is rectangular. 
     
     
         6 . The injector according to  claim 1 , wherein said pressure equalizing cushion has sealing ends. 
     
     
         7 . The injector according to  claim 1 , wherein said pressure equalizing cushion comprises a valve for supply of hydraulic fluid. 
     
     
         8 . The injector according to  claim 1 , wherein said pressure equalizing cushion comprises a ventilation valve to drain possible gas from said hydraulic fluid. 
     
     
         9 . The injector according to  claim 2 , wherein said pressure equalizing cushion comprises a flexible metallic hose. 
     
     
         10 . The injector according to  claim 3 , wherein said pressure equalizing cushion comprises a flexible metallic hose. 
     
     
         11 . The injector according to  claim 2 , wherein the cross section of said pressure equalizing cushion is rectangular. 
     
     
         12 . The injector according to  claim 3 , wherein the cross section of said pressure equalizing cushion is rectangular. 
     
     
         13 . The injector according to  claim 4 , wherein the cross section of said pressure equalizing cushion is rectangular. 
     
     
         14 . The injector according to  claim 2 , wherein said pressure equalizing cushion has sealing ends. 
     
     
         15 . The injector according to  claim 3 , wherein said pressure equalizing cushion has sealing ends. 
     
     
         16 . The injector according to  claim 4 , wherein said pressure equalizing cushion has sealing ends. 
     
     
         17 . The injector according to  claim 5 , wherein said pressure equalizing cushion has sealing ends. 
     
     
         18 . The injector according to  claim 2 , wherein said pressure equalizing cushion comprises a valve for supply of hydraulic fluid. 
     
     
         19 . The injector according to  claim 3 , wherein said pressure equalizing cushion comprises a valve for supply of hydraulic fluid. 
     
     
         20 . The injector according to  claim 4 , wherein said pressure equalizing cushion comprises a valve for supply of hydraulic fluid.