Apparatus for inducing vibration in a drill string

Abstract

An insert having a plurality of ports creating angled passageways through the walls of the insert is positioned in a drill string for altering fluid flow in the drill string and inducing vibration sufficient to speed up directional drilling and to prevent differential sticking in wellbores. Boundary layer flow along the walls of the drill string is drawn into an upstream group of ports to commingle with fluid in the central bore of the drill string and the insert. The flow is separated at a downstream group of ports and angled passageways cause the flow to be directed radially outward inducing vibration into the drill string.

1 . A vibration inducing apparatus for controlling fluid flow within a bore of a drill string for creating vibration within said drill string comprising: 
 a venturi insert fit to the drill string's bore and being axially moveable therein, the venturi insert having a body fit to the bore and having a central tubular bore formed therethrough for forming an annular wall extending between the drill string and the tubular bore; and    a tubular fluid inlet formed in the insert's tubular bore projecting upstream from the annular wall;    a tubular fluid outlet formed in the insert's tubular bore projecting downstream from the annular wall; wherein    the annular wall comprising:    a first angled wall extending downstream between the tubular fluid inlet and the body and radially outwards therefrom;    a second angled wall extending downstream between the body and the tubular fluid outlet and radially inwards therefrom; and    a plurality of ports formed in the first and second angled walls, the ports forming angled passages being directed radially inwards and downstream and radially outwards and downstream;    wherein at least a portion of the fluid flows through the insert's angled passages and at least a portion of the fluid flows through the bore, the turbulence and pattern of the flow created upon exiting the insert inducing vibration in the drill string.    
   
   
       2 . The vibration inducing apparatus as described in  claim 1  further comprising a housing for positioning the venturi insert within the at least a portion of the drill string, further comprising: means for securing the venturi insert within a bore of the housing for axial movement therein.  
   
   
       3 . The vibration inducing apparatus as described in  claim 2  wherein the means for securing the venturi insert in the housing further comprises: 
 an internal sleeve fit within the bore of the housing for housing the venturi insert and receiving the fluid flow, the insert being axially moveable therein; and    upper and lower retaining rings for retaining the internal sleeve in the housing's bore and for limiting the axial movement of the venturi insert therebetween.    
   
   
       4 . The vibration inducing apparatus as described in  claim 3  further comprising: 
 a shoulder formed in the housing against which the lower retainer ring is supported;    a snap ring against which the upper retainer ring is supported: and    a snap ring groove formed in the housing for accepting the snap ring for retaining the internal sleeve and retaining rings in the housing bore.    
   
   
       5 . The vibration inducing apparatus as described in  claim 2  wherein the housing is a pup joint threaded at an upper and lower end for connection to the drill string.  
   
   
       6 . The vibration inducing apparatus as described in  claim 1  wherein the plurality of ports are angled from about 24° to about 28°.  
   
   
       7 . The vibration inducing apparatus as described in  claim 6  wherein the plurality of ports are angled 26°.  
   
   
       8 . The vibration inducing apparatus as described in  claim 1  wherein the insert's bore is sized sufficient to permit passage of a wireline therethrough.  
   
   
       9 . The vibration inducing apparatus as described in  claim 1  wherein a number of the ports varies depending upon a diameter of the venturi insert.  
   
   
       10 . The vibration inducing apparatus as described in  claim 5  wherein a plurality of pup joints are threadedly engaged within a drill string at selected intervals for inducing vibration therealong.