The casing head in a conventional wellhead system is the lowest part of the wellhead assembly and is almost always connected to the surface casing string. It supports the remaining parts of the wellhead and completion equipment. The casing head performs the following functions:
Provides a means for attachment to the surface casing string
Allows for suspending the next casing string, usually the first intermediate string in the well
Supports the blowout preventers (BOP) while drilling
Provides outlets for fluid returns
Provides a means to test the blowout preventers (BOP) while drilling
May provide a test port for testing welded or other non-threaded bottom casing head connections
May also be referred to by the following names, “A-Section”, “Braden Head” or “Starting Head”
C-22 Casing Heads
Sentry casing heads incorporate the industry workhorse C-22 geometry that will accept a standard C-21 or C-22 casing hanger. Additionally, the Sentry C-22 casing head product line has been engineered with the option to integrate full sets of lock-down screws (LDS) in the upper flange in order to provide mechanical casing hanger retention and/or pack-off actuation.
The C-22 casing head is designed for light to intermediate casing string weights
It incorporates a straight bowl design
Is available with Lock Down Screws (LDS) in the upper flange for mechanical casing hanger retention
Can utilize Bowl Protector lockdown screws
It may be equipped with or without a baseplate
Available in multiple bottom connection configurations including Slip-Lock
C-29 Casing Heads
The Sentry C-29 casing head has all of the same features and benefits as the C-22, but is designed for intermediate to extreme casing weights. This head design can also handle the standard C-21 and C-22 casing hangers.
The C-29 casing head is designed for intermediate to extreme casing loads
It has a deeper upper bowl to accommodate the taller C-29 casing hanger
The C-29 casing head can also utilized the C-21 and C-22 casing hangers
Is available with Lock Down Screws (LDS) in the upper flange for mechanical casing hanger retention
It may be equipped with or without a baseplate
Available in multiple bottom connection configurations including Slip-Lock