remain in the hole and are not removed after deflection has been accomplished. 

 In soft formations a knuckle joint, a coupling which holds the drill bit at an 

 angle to the main drill string, may be used to drill sufficient hole so that a flex- 

 ible drill string will follow into the deflected hole, and no whipstock is required. 



Figure 32-3. Whipstock being removed from well after use (courtesy Standard Oil Com- 

 pany of California). 



686 



