Liner hangers and liner top packers to improve completion well construction design and operations

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.

Well trajectory complexity, depth, pressure, temperature, and cost have increased the challenges of well construction design, planning, and operations. Long horizontal laterals in unconventional shale wells, liner drilling, extended reach wells, cemented and uncemented liners require high-performance liner hanger systems capable of: rotation to reach total depth, robust setting mechanisms tolerant of higher solids content, liner top packer sealing elements which can survive run in hole, circulating and cementing at higher rates to lift and homogenize the mud around the liner, all while controlling the equivalent circulating density (ECD) to avoid approaching the fracture gradient and damaging the formation. Once set on depth, seal integrity must be maintained through high-pressure fracturing operations in the case of some uncemented liner applications and years of pressure and thermal cycling during production.