Method for releasing stuck drill string

Abstract

A method for releasing a drill string stuck against a wall of a well bore due to pressure differential between the hydrostatic pressure of a fluid in the well bore and the pressure of a formation at the point where the drill string is stuck. The method includes injecting a first fluid into the annulus via the drill string and simultaneously injecting a second fluid into the annulus at an upper end of the annulus. The first fluid and the second fluid are injected into the annulus at a volume and rate sufficient to cause at least one of the first fluid and the second fluid to penetrate the formation and increase the pressure of the formation adjacent the well bore so that the pressure of the formation adjacent the well bore is substantially equalized with the pressure of the well bore. A jarring force is simultaneously exerted to the drill string to cause the drill string to release.

1 . A method for releasing a drill string stuck against a wall of a well bore due to pressure differential between a hydrostatic pressure of a fluid in the well bore and a pressure of a formation at the point where the drill string is stuck, the drill string and the well bore forming an annulus, the method comprising: 
 increasing the pressure of the formation adjacent the point at which the drill string is stuck against the wall of the well bore so that the pressure of the formation adjacent the point at which the drill string is stuck is substantially equal to or greater than the hydrostatic pressure of the well bore.    
   
   
       2 . The method of  claim 2  further comprising the step of exerting a jarring force to the drill string.  
   
   
       3 . A method for releasing a drill string stuck against a wall of a well bore due to pressure differential between a hydrostatic pressure of a fluid in the well bore and a pressure of a formation at the point where the drill string is stuck, the drill string and the well bore forming an annulus, the method comprising: 
 causing fluid to pass into the formation from the well bore adjacent the point at which the drill string is stuck against the wall of the well bore so that the pressure of the formation adjacent the point at which the drill string is stuck is substantially equalized with the hydrostatic pressure of the well bore; and    simultaneously exerting a jarring force to the drill string.    
   
   
       4 . The method of  claim 3  wherein the fluid is water.  
   
   
       5 . The method of  claim 4  wherein the fluid includes a friction reducer.  
   
   
       6 . The method of  claim 4  wherein the fluid includes a gel.  
   
   
       7 . The method of  claim 3  wherein the fluid is oil.  
   
   
       8 . The method of  claim 7  wherein the fluid includes a gel.