Mono-bore retrievable whipstock

Abstract

A whipstock for mono-bore applications is disclosed which could be run in on wireline. The setting mechanism allows for a predetermined setting force to be applied to the anchor slip or slips before and automatic release from the running tool. The slips are further retained in position by a ratchet block, which is mounted to the whipstock body to work with the slips against release during removal of the milling equipment. The whipstock body is formed to place the upper end against the casing after the slips are driven out so that the onset of milling will not result in damage to the upper end. A retrieval tool engages an opening in the whipstock to release the grip of the slips and bring the assembly to the surface.

We claim:  
     
         1 . A method of making a lateral in a mono-bore, comprising: 
 running in a whipstock and a setting tool on wireline;    setting at least one slip to secure the whipstock in the mono-bore;    producing the lateral.    
     
     
         2 . The method of  claim 1 , further comprising: 
 ensuring a predetermined minimum force is applied to said slip after said slip is moved to a set position: 
 thereafter releasing said setting tool from said whipstock.  
   
     
     
         3 . The method of  claim 1 , further comprising: 
 moving said slip outwardly against said mono-bore to secure said whipstock;    pivoting said whipstock about a pivot point, due to said moving of said slips outwardly to bring that portion of the upper end of the whipstock which is opposed to the sloping surface on the whipstock, closer to said mono-bore.    
     
     
         4 . The method of  claim 2 , further comprising: 
 using a tension rod to move said slip to its said set position;    using a ring at least in part surrounding said tension rod and, while selectively retained to said tension rod, allowing force to be transmitted to said slip in said set position.    
     
     
         5 . The method of  claim 4 , further comprising: 
 using a mating thread between said tension rod and said ring, which pulls apart at the application of a predetermined force.    
     
     
         6 . The method of  claim 5 , wherein: 
 said mating thread pulls apart with an applied force to said tension rod of at least about 7,500 pounds.    
     
     
         7 . The method of  claim 1 , further comprising: 
 moving said slip on an inclined ramp to place it in a set position;    locking said slip against movement back down said ramp after reaching its said set position.    
     
     
         8 . The method of  claim 7 , further comprising: 
 accomplishing said locking with a locking member, which digs into said slip and is mounted on an incline at least as steep as said inclined ramp.    
     
     
         9 . A whisptock for downhole use, comprising: 
 an elongated body having an external taper extending from near a top end thereof;    at least one slip actuable outwardly toward a set position, in contact with a tubular downhole, by movement of an elongated member extending though said elongated body.    
     
     
         10 . The whipstock of  claim 9 , further comprising: 
 a retainer at least in part circumscribing said elongated member and selectively releaseable there from after said slip has been moved to its said set position and an additional force of a predetermined value has been transmitted to said slip through said elongated member.    
     
     
         11 . The whipstock of  claim 9 , further comprising: 
 an inclined ramp on said body on which said slip is operably movable by said elongated member, said slip movable outwardly from said body as it is urged along said ramp;    a locking member to engage said slip after a predetermined movement along said ramp to selectively retain it against opposite movement along said ramp.    
     
     
         12 . The whipstock of  claim 11 , wherein: 
 said locking member digs into said slip to selectively retain it and comprises a grip surface oriented on an angle at least as steep as said ramp.    
     
     
         13 . The whipstock of  claim 9 , wherein: 
 said body comprises a pivot point such that extension of said slip pivots said body about said pivot point to bring the top end of said body, located opposite said external taper closer to the tubular downhole.    
     
     
         14 . The whipstock of  claim 10 , further comprising: 
 an inclined ramp on said body on which said slip is operably movable by said elongated member, said slip movable outwardly from said body as it is urged along said ramp;    a locking member to engage said slip after a predetermined movement along said ramp to selectively retain it against opposite movement along said ramp.    
     
     
         15 . The whipstock of  claim 14 , wherein: 
 said locking member digs into said slip to selectively retain it and comprises a grip surface oriented on an angle at least as steep as said ramp.    
     
     
         16 . The whipstock of  claim 15 , wherein: 
 said body comprises a pivot point such that extension of said slip pivots said body about said pivot point to bring the top end of said body, located opposite said external taper closer to the tubular downhole.    
     
     
         17 . The whipstock of  claim 10 , wherein: 
 said predetermined force is at least about 7, 500 pounds.    
     
     
         18 . The whipstock of  claim 9 , further comprising: 
 a setting tool operable on wireline and operably connected to said body and said elongated member to deliver the whipstock into a mono-bore and selectively apply a force to said elongated member to move said slip into its set position and to apply a predetermined force to said slip before forcing said elongated member to release for removal from said body with said setting tool.    
     
     
         19 . The whipstock of  claim 18 , further comprising: 
 a retainer at least in part circumscribing said elongated member and selectively releasable therefrom after said slip has been moved to its said set position and an additional force of a predetermined value has been transmitted to said slip through said elongated member.    
     
     
         20 . The whipstock of  claim 19 , wherein: 
 said body comprises a pivot point such that extension of said slip pivots said body about said pivot point to bring the top end of said body, located opposite said external taper closer to the tubular downhole.    
     
     
         21 . The method of  claim 1 , further comprising: 
 providing a dovetail connection between said setting tool and said whipstock.    
     
     
         22 . The whipstock of  claim 9 , further comprising: 
 a setting tool releasably connected to said body and rotationally locked thereto for selective actuation and retrieval of said elongated member.    
     
     
         23 . The whipstock of  claim 12 , wherein: 
 said locking member is slidably mounted so as to increase holding force on said slip in response to an uphole force applied to said body.    
     
     
         24 . The whipstock of  claim 10 , wherein: 
 said retainer releases at a value of shear up to the tensile capacity of said elongated member.