High torque rotatable progressive cavity drive rods and connectors

Abstract

A drive rod string for a progressive cavity pump. The drive rod string includes a plurality of drive rods. Each drive rod has a pair of opposed ends, wherein each end terminates in a frustoconical pin having tapered threading and having a radially extending cylindrical shoulder. A plurality of connectors are provided to connect the drive rods. Each connector is attached to one of the ends of the drive rods, wherein each connector has a pair of opposed frustoconical threaded recesses which extend from a pair of opposed shoulders which mate with the cylindrical shoulders of the frustoconical pins. An internal secondary stop within said connector acts as a positive stop in each connector for the frustoconical pin.

1 . A drive rod string for a progressive cavity pump comprising: 
 a plurality of drive rods, each drive rod having a pair of opposed ends, wherein each said end terminates in a frustoconical pin having tapered threading and having a radially extending cylindrical shoulder;    a plurality of connectors, each connector attached to one said end of a pair of said drive rods, wherein each said connector has a pair of opposed frustoconical threaded recesses which extend from a pair of shoulders which mate with said cylindrical shoulders of said frustoconical pins; and    an internal secondary stop within said connector acting as a positive stop in each said connector for said frustoconical pin.    
     
     
         2 . A drive rod string as set forth in  claim 1  wherein said internal secondary stop is spaced from each frustoconical pin until said pin is elongated from stress.  
     
     
         3 . A drive rod string as set forth in  claim 1  wherein each said frustoconical pin cylindrical shoulder has a surface which is roughened and wherein each said connector pair of shoulders have surfaces which are roughened and wherein said mating of said roughened surfaces resists rotational movement.  
     
     
         4 . A drive rod string as set forth in  claim 1  wherein said drive rod string connectors can accommodate up to 1,750 foot pounds of torque to said drive rod string.  
     
     
         5 . A connector for a pair of drive rods, wherein each drive rod terminates in a frustoconical pin having tapered threading and having a radially extending cylindrical shoulder with substantially no undercut between said tapered threading and said shoulder and wherein said cylindrical shoulder has a roughened surface, which connector comprises: 
 a pair of opposed frustoconical threaded recesses, each said frustoconical recess extending from a shoulder which will mate with said cylindrical shoulder of said frustoconical pin; and    an internal secondary stop within said connector between said frustoconical threaded recesses which acts as a positive stop.    
     
     
         6 . A drive rod string as set forth in  claim 1  wherein said internal secondary stop is normally spaced from said frustoconical pin when said pin is threaded into said recess.  
     
     
         7 . A method of operating a progressive cavity device, which method comprises: 
 positioning a progressive cavity device downhole in a well by attaching a drive rod string to said device, wherein said drive rod string includes a plurality of drive rods, each drive rod having a pair of opposed ends, each said end terminating in a frustoconical pin having tapered threading and having a radially extending cylindrical shoulder and includes a plurality of connectors, each connector having a pair of opposed frustoconical threaded recesses, each said frustoconical recess extending from a shoulder which will mate with said cylindrical shoulder of said frustoconical pin; and    rotating said drive rod string to power said progressive cavity device.