A sliding sleeve is a standard component for the completion of an oil or gas well. Their main uses are to shut off flow from one or more reservoir zones or to regulate pressure between zones.
There are two main categories of sliding sleeves: open/close and choking. Open/close sleeves are shifted between a full open position and a closed position. They are used to shut off flow from a zone for economic reasons or to shut off a zone that is depleting or producing too much water. In multi-zone wells, they are used to regulate which zones to produce from and which ones to shut off. Mechanically actuated sleeves are simple and inexpensive but require actuation by a "lock," which must be run in the well on wireline or coiled tubing. Hydraulically actuated sleeves are more complicated but can be actuated from a small pump at surface. King sleeves can be used to regulate the pressure between two or more zones. They are also used to regulate the flow of fluid into a well during proppant fracturing or hydraulic fracturing operations. Choking sleeves are all hydraulically actuated and have a much more complex design than open/close sleeves.