Oil and gas companies always intend to produce hydrocarbon and avoid producing water. Controlling the rate is one way avoiding early water breakthrough. Drilling horizontal well closed to the top of oil zone and producing the well under its critical rate are other ways. Injecting water inhibitor or water blocker is tried sometimes to block water.
Figure 1 shows other way to block water encroach into the wellbore. The perforated expandable liner is wrapped by water swellable sleeve. The water swellable sleeve acts as smart screen filter to block water and allow oil to pass into the wellbore. If it is desired, a sand screen can be installed between the liner and the sleeve. The water zone is plugged with cement slurry until the top of the cement above water oil contact (WOC). This is to ensure no early swelling during running the swellable sleeve. Downhole tools companies can help to install such smart screen.
The water swellable sleeve will swell when water reaches the sleeve and is then blocked. Oil only is still going through the sleeve until the water reach the upper end of the sleeve. When all the openings of the sleeve are closed, no more fluid can enter the wellbore. Alternatively, to avoid external liner blocking, the water swellable material can be install inside the liner as a shroud. An example of water swellable material is starch-polyacrylate acid graft copolymer.
Recommended reading and water swellable material for diaper:
