Method for sealing a well casing and surrounding strata

Abstract

A method for sealing a well casing, including any perforations that are intentionally provided through the well casing or which may have occurred through the deterioration of the casing, includes the steps of disposing a seal injection assembly that is adapted for ejecting a grout therefrom at a depth that is proximate the perforations in the casing and of ejecting a quantity of a poly-urethane grout through the perforations sufficient to seal the space intermediate the exterior of the casing and the surrounding materials and to also seal the perforations in the casing. If perforations occur at different depths in the casing the process is repeated at the different depths. The perforations are created, if need be, by the use of a well casing perforator that is positioned where a vertical fluid flow is occurring outside the casing. The step of determining where the fluid flow is occurring is accomplished prior to the step of using the well casing perforator. The seal injection assembly is then used to eject the grout as described above through the perforations. If the perforations occur due to a defect arising in the casing, the step of using the well casing perforator may be eliminated.

What is claimed is:  
     
         1 . A method for sealing a well casing and surrounding strata, comprising the steps of: 
 (a) disposing means for ejecting a grout proximate a perforation in a casing; and    (b) ejecting said grout through said perforation.    
     
     
         2 . The method of  claim 1  wherein said step of ejecting said grout includes the step of ejecting a poly-urethane grout.  
     
     
         3 . The method of  claim 1  wherein said step of disposing means for ejecting a grout proximate a perforation in a casing includes the step of disposing a seal injection assembly proximate said perforation.  
     
     
         4 . The method of  claim 3  wherein the step of disposing a seal injection assembly proximate said perforation includes the step of aligning said seal injection assembly proximate said perforation so that a lower packer is disposed below said perforation and that an upper packer is disposed above said perforation.  
     
     
         5 . The method of  claim 4  including the step of activating said lower and said upper packer prior to the step of ejecting said grout through said perforation.  
     
     
         6 . The method of  claim 5  including the step of deactivating said lower and said upper packer after the step of ejecting said grout through said perforation.  
     
     
         7 . The method of  claim 1  including the step of perforating a sidewall of said casing to provide said perforation prior to the step of disposing means for ejecting a grout proximate a perforation in said casing.  
     
     
         8 . The method of  claim 7  including the step of perforating a sidewall of said casing so as to provide a plurality of perforations prior to the step of disposing means for ejecting a grout proximate said plurality of perforations in said casing.  
     
     
         9 . The method of  claim 1  wherein the step of disposing means for ejecting a grout proximate a perforation in a casing includes the step of disposing means for ejecting a grout proximate a defect perforation in said casing.  
     
     
         10 . The method of  claim 1  including the steps of repeating the steps of: 
 (a) disposing means for ejecting a grout proximate a perforation in a casing; and  
 (b) ejecting said grout through said perforation at a plurality of depths in said casing;  
 wherein at least one additional perforation is provided through said casing at each of said plurality of depths.  
 
     
     
         11 . The method of  claim 10  wherein the repeated include the steps of: 
 (a) disposing means for ejecting a grout proximate a second defect perforation in a casing; and  
 (b) ejecting said grout through said second defect perforation at a plurality of depths in said casing.  
 
     
     
         12 . The method of  claim 1  wherein said step of disposing means for ejecting a grout proximate a perforation in a casing includes the step of disposing a chemical grout injector proximate said perforation.  
     
     
         13 . The method of  claim 12  wherein the step of disposing a grout injector proximate said perforation includes the step of disposing a three-component chemical grout injector proximate said perforation.  
     
     
         14 . The method of  claim 1  including the step of determining the depth in said casing where a vertical flow of fluid is occurring at an exterior location of said casing followed by the step of perforating a sidewall of said casing proximate said depth in said casing where a vertical flow of fluid is occurring prior to the step of disposing means for ejecting a grout proximate a resulting perforation that is provided in said casing.