Whipstock kick off radius

Abstract

An improved whipstock design features a ramp having a lower terminus at the location of the expected window bottom. The lower end of the whipstock ramp transitions gradually from a preferably flat guide surface to a more drastic exit orientation that is preferably obtained by going to an arcuate exit of a rather large radius to present a smooth transition from the flat guide surface to an orientation that allows kick-out to occur by the end of the ramp. This in turn allows the ramp end to closely approximate the window bottom to reduce the risk of creation of a pocket near the window bottom that could trap or damage equipment delivered in subsequent runs.

1 . A whipstock, comprising: 
 an elongated body having a longitudinal axis and a ramp surface having an upper and a lower end;    said ramp surface comprising a lowermost segment and an adjacent segment, said lowermost segment having an arcuate portion.    
   
   
       2 . The whipstock of  claim 1 , wherein: 
 said lowermost segment comprising no more than 20% of the length of said ramp.    
   
   
       3 . The whipstock of  claim 1 , wherein: 
 said lowermost segment providing a continuation of said adjacent segment initially in the same plane.    
   
   
       4 . The whipstock of  claim 1 , wherein: 
 said elongated body further comprises a cylindrical segment at its lower end and said lowermost segment reaching said cylindrical segment at an angle of at least 10 degrees with said longitudinal axis.    
   
   
       5 . The whipstock of  claim 1 , wherein: 
 said arcuate portion comprises more than one radius.    
   
   
       6 . The whipstock of  claim 5 , wherein: 
 said radii decrease in length on said lowermost segment in a direction toward said lower end of said ramp.    
   
   
       7 . The whipstock of  claim 1 , wherein: 
 said lowermost segment providing a continuation of said adjacent segment initially within 5 degrees of the plane of said adjacent segment.    
   
   
       8 . The whipstock of  claim 2 , wherein: 
 said lowermost segment providing a continuation of said adjacent segment initially within 5 degrees of the plane of said adjacent segment.    
   
   
       9 . The whipstock of  claim 8 , wherein: 
 said lowermost segment providing a continuation of said adjacent segment initially in the same plane.    
   
   
       10 . The whipstock of  claim 8 , wherein: 
 said elongated body further comprises a cylindrical segment at its lower end and said lowermost segment reaching said cylindrical segment at an angle of at least 10 degrees with said longitudinal axis.    
   
   
       11 . The whipstock of  claim 10 , wherein: 
 said arcuate portion comprises more than one radius.    
   
   
       12 . The whipstock of  claim 11 , wherein: 
 said radii decrease in length on said lowermost segment in a direction toward said lower end of said ramp.    
   
   
       13 . The whipstock of  claim 12 , wherein: 
 said lowermost segment providing a continuation of said adjacent segment initially in the same plane.