Apparatus and method of oscillating a drill string

Abstract

Apparatus and methodology for reducing frictional forces on drilling apparatus when being progressed or retracted within a well bore. This is achieved through mechanical or hydraulic action on the drilling fluid to create a fluid pressure differential which is transmitted on to the drill string via pumps, causing the drill string to oscillate. The oscillation reduces the frictional interface between the drill string and the well bore, thus enabling increased depth or reach of the well bore.

1 . Apparatus for oscillating a drill string within a well bore, comprising one or more pumps for introducing fluid into a drill string and a modifying means, wherein the modifying means induces a fluid pressure differential which is transmitted to the drill string via the pumps, and wherein the fluid pressure differential causes said drill string to oscillate.  
     
     
         2 . Apparatus as claimed in  claim 1 , wherein the modifying means is mechanically operated.  
     
     
         3 . Apparatus as claimed in  claim 1 , wherein the modifying means is hydraulically operated.  
     
     
         4 . Apparatus as claimed in any preceding claim, wherein the one or more pumps communicate with at least one fluid containment vessel.  
     
     
         5 . Apparatus as claimed in  claim 4 , wherein said fluid containment vessels are mud pits.  
     
     
         6 . Apparatus as claimed in any preceding claim, wherein the one or more pumps are connected to the drill string by flow lines.  
     
     
         7 . Apparatus as claimed in any preceding claim, wherein the modifying means provides an oscillating mechanism.  
     
     
         8 . Apparatus as claimed in  claim 7 , wherein the oscillating mechanism is provided by periodical expulsion of a predetermined volume of fluid from the pump.  
     
     
         9 . Apparatus as claimed in  claim 8 , wherein the volume of fluid is expelled from the pump by a choking means.  
     
     
         10 . Apparatus as claimed in  claim 7 , wherein the oscillating mechanism is provided by a turbine.  
     
     
         11 . Apparatus as claimed in  claim 10 , wherein the turbine is accentrically positioned.  
     
     
         12 . Apparatus as claimed in  claim 7 , wherein the oscillating mechanism is provided by an acentric helix.  
     
     
         13 . Apparatus as claimed in  claim 7 , wherein the oscillating mechanism is provided by one or more motors.  
     
     
         14 . Apparatus as claimed in  claim 13 , wherein the one or more motors are connected to a piston.  
     
     
         15 . Apparatus as claimed in  claim 1 , wherein the modifying means is provided on the drill string, or on the pumps.  
     
     
         16 . Apparatus as claimed in  claim 6 , wherein the modifying means is provided on the flow lines.  
     
     
         17 . A method for running a drill string into a well bore comprising creating a fluid pressure differential by mechanical or hydraulic means, and transmitting the fluid pressure differential to the drill string, the fluid pressure differential thereby causing the drill string to oscillate.