A liner hanger, as the name suggests, secures and supports the liner. It uses mechanical slips to grip the inside of the casing a pre-determined distance above the casing shoe. The space between the liner hanger and the casing shoe is called the liner lap. Liner hangers can be set hydraulically, mechanically, or a mixture of the two. Most liners are cemented back to the liner hanger. Some systems are designed to allow liner rotation after the hanger is set as the ability to rotate has been shown to improve cement bond, particularly in long high angle wells.4 The price of having improved cement integrity is a mechanically more complex hanger system.
Some liner hanger systems have a polished bore receptacle (PBR) above the liner hanger. This enables the base of the production tubing to be stabbed into the liner top, providing both a seal and a continuous conduit for produced fluids (Fig. 3.15).
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