Patent ID: 7527095

Claim:
A method of creating a zonal isolation adjacent to a target zone in an underground wellbore, the method comprising: inserting a slurry injection tubing through a wellhead into the wellbore; arranging a particle accumulation means in an annular space surrounding the slurry injection tubing at a location between the target zone and the wellhead; and pumping a slurry comprising a carrier fluid and granular material via the slurry injection tubing into the annular space, such that at least some granular material accumulates adjacent to the particle accumulation means and the accumulated granular material forms a zonal isolation comprising packed granular material adjacent to the particle accumulation means; wherein the particle accumulation means comprises a means for removing liquid from the slurry, selected from the group consisting of a fluid permeable barrier in the annular space and a fluid return conduit surrounding the slurry injection tubing; wherein during pumping of the slurry at least part of the carrier fluid is removed from the slurry and wherein the granular material is induced to accumulate in a region of the annular space which is located between the target zone and the particle accumulation means, such that the particle accumulation means is arranged between the accumulated granular material and the wellhead.