Casing hangers are devices that allow casing to be set in the well bore during the drilling phase of an oil or gas well. There are two basic designs of casing hanger,
– Slip-type
– Mandrel type
The slip-type is the conventional and most commonly used. The mandrel-type is normally used when special needs arise during the building of the well. Both allow for the Tens of Thousands of pounds in weight of the casing string weight to be transferred from the derrick of the drilling rig to the load shoulder in a casing head or spool. A Casing Hanger performs the following functions:
— Suspends the casing load
— Transfers casing weight
— Centers casing
— Provides a primary seal in the casing annulus
— Creates an annular space
— Allows for testing of connections
C-21 Casing Hangers
Sentry C-21 casing hangers are the non-automatic solution for hanging casing. The split bowl utilizes the same upper slip segments as the C-22 and C-29 hangers and incorporates a separate seal assembly. This has two benefits. It prevents any well or test pressure from adding to the radial compression of the slip segments. And it is a primary casing seal that can be replaced during workover operations without picking up the pipe.
The Type-H seal ring utilizes S (OD) and CS (ID) seals to provide the primary seal on the string of casing being suspended in the casing hanger
C-22 Casing Hangers
Sentry C-22 automatic casing hangers are designed for use with the venerable C-22 casing heads and are an industry standard around the world.
C-29 Casing Hangers
Sentry C-29 casing hangers incorporate a set of 8 independent slip segments. Of these 4 are located above the packing element and 4 below the packing element. These hangers are best suited for extreme casing string weights.
Mandrel Casing Hangers
Sentry Mandrel-type casing hangers are used when special needs arise during the building of the well. They can be customized to meet the needs of your well design in almost any design or configuration. Consult your Sentry Sales Representative to discover how we can help design one to fit your unique requirements.
- Mandrel casing hangers can be utilized in conjunction with a pack-off to minimize the time spent setting casing by allowing for the pipe to be set and the annulus sealed without removing the BOP’s
- A mandrel casing hanger can be used to secure the well for the safe installation of FRAC equipment by incorporating a back pressure valve profile in the ID
- The mandrel hanger can be utilized to simply prevent any hot work normally performed for the setting of slip-type casing hangers
A mandrel casing hanger may be designed to meet all three needs mentioned above, in one casing hanger.