Patent ID: 8720568

Claim:
A method for plugging a substantially horizontal wellbore, the method comprising: introducing into the wellbore a slurry composition comprising a carrier fluid and a granular borate source material, wherein the borate source material is selected from the group consisting of a sodium perborate monohydrate; a sodium perborate trihydrate; and any combination thereof; allowing the slurry composition to settle in the horizontal wellbore and at least partially fill at least a portion of the horizontal wellbore in a direction vertical to the substantially horizontal wellbore; and exposing the slurry composition to a sufficient amount of aqueous fluid whereby the aqueous fluid swells the granular borate source material to thereby expand the slurry composition to the point that the expanded slurry composition substantially fills at least a portion of the horizontal wellbore in a direction vertical to the horizontal wellbore, thereby plugging the substantially horizontal wellbore.