Method for Zone Isolation in a Subterranean Well

Abstract

A method is for zone isolation in a subterranean well. The well is provided with a pipe body at least in a portion. The method includes providing a plug over a longitudinal section of the well, the plug covering substantially the entire cross section of the well at least in a portion of the longitudinal section, so that the plug fills the inside, of a pipe body and an annulus between the outside of the pipe body and a surrounding well body.

1 . A method for zone isolation in a subterranean well, the well being provided with a pipe body, at least in a portion, the method comprising:
 (A) providing a plug over a longitudinal section of the well, the plug covering substantially the entire cross section of the well at least in a portion of the longitudinal section, so that the plug fills the inside of the pipe body and an annulus between the outside of the pipe body and a surrounding well body, wherein (A) comprises:   (A1) lowering a perforation tool into the pipe body to the longitudinal section where the plug is to be set:   (A2) forming perforations the pipe body along the longitudinal section the perforation tool;   (A3) with a washing tool which is attached to a string allowing through-flow and which is lowered to the longitudinal section L 1 , pumping a washing fluid down the string and out into the pipe body via the washing tool;   (A4) with a directional-control means connected to the washing tool, directing the washing fluid into the annulus between the outside of the pipe body and the surrounding well body; and   (A5) pumping a fluidized plugging material down the string and out into the pipe body, and thereby also into the annulus the perforations in the pipe body.   
     
     
         2 . The method in accordance with  claim 1 , wherein a displacement member is used to further displace and distribute the fluidized plugging material in the pipe body and further into the annulus. 
     
     
         3 . The method in accordance with  claim 1 , wherein perforation (A2) and washing (A3, A4) are performed m separate trips down the well. 
     
     
         4 . The method in accordance with  claim 1 , wherein perforation (A2 ) and washing (A3, A4) are performed in one and the same trip down the well. 
     
     
         5 . The method in accordance with  claim 1 , wherein the method further includes leaving the perforation tool in the well. 
     
     
         6 . The method in accordance with  claim 1 , wherein the method further includes leaving the washing tool in the well. 
     
     
         7 . The method in accordance with  claim 1 , wherein, after (A), the method comprises:
 (B) drilling out a central, through-going portion of the plug, so that there is at least a cross-sectional section of the plug left on the outside of the pipe body.   
     
     
         8 . The method in accordance with  claim 1 , wherein the method includes providing one or more perforations in a portion of the pipe body in a portion outside the longitudinal section in which the plug has been set. 
     
     
         9 . The method in accordance with  claim 1 , wherein the fluidized plugging material includes cement slurry for the formation of a cement plug. 
     
     
         10 . The method in accordance with  claim 1 , wherein the fluidized plugging material includes unconsolidated mass for the formation of an unconsolidated-mass plug.