Figure 32-9. Development of flank oil production of a salt dome by the use of directionally 

 drilled wells. 



the producing formation. A straight hole at C which has missed the objective 

 sand by penetrating the section on the wrong side of the fault might also be 

 turned into a productive well by sidetracking and directionally drilling the well 

 to cross the fault. 



A final example of the applications of directional drilling is shown in Figure 

 32-9. Here a preliminary test well A has bottomed in salt after penetrating an 

 unproductive section capping the salt dome. A second test well B on the flank 

 of the dome has penetrated a productive zone after passing through the salt 

 overhang. It may now be possible to go back into well A and sidetrack the hole — - 

 directionally drilling the sidetracked hole to tap the flank production. This 

 procedure would save the cost of a new hole down to the sidetracked depth. 



Inasmuch as drilling through the caprock of a salt dome is sometimes 

 costly and difficult, it may be desirable, in the further development of this field, 

 to avoid drilling through the salt overhang in order to reach the flank production. 

 In this instance, directionally drilled wells may be used to reach the objective. 

 Such wells may be allowed to lose drift angle and become vertical after passing 

 below the salt overhang, or they may be drilled so that the well is parallel to the 



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