API 6A casing spool/oilfield equipment/wellhead equipment

Description: The casing spool has a top bowl to accommodate the casing hanger. The spool also has a bottom bowl with a packoff seal and a flange or clamp hub for mounting it on top of a casing head or previous spool. Outlets are provided for annular access. Multiple casing spools may be stacked to hang intermediate and production casing strings.

Functions
Provides a load shoulder in the top bowl to support a casing hanger.
Provides a controlled bore in the top bowl for the casing hanger seal.
Provides a seal in the bottom bowl to pack off the previous casing

string and isolate flange or clamp hub seals internal casing pressure.
ovides side outlets for annular access.
Provides a port for pressure-testing casing seals and flange connections.
Provides for supporting and testing BOPs while drilling.
Provides retention for bowl protector while drilling.

C-22
Features
Has a straight bowl.
Accepts C-21 nonautomatic-sealing casing hanger w/type H seal ring,
C-22/C-122 automaticsealing casing hanger.
C-22-BP-ET has bowl-protector lockdown screws in the top flange.
C-22 eliminates the need for lockdown screws to retain bowl protectors.
Accepts Surface Wellhead C-22 BOP test plugs.
Bottom bowl preparations available are:
-S/FS-BG Seal Bushing -Integral FS seal
-FS-BG bushing -PI pressure-intensified seal
-SBMS II metal-to-metal seal-RCMS (Rough Casing Metal Seal)
Is available with threaded, studded or flanged outlets. Benefits
Straight bowl prevents protectors, casing hangers and test plugs.
C22-EG reduces number of leak paths, lowers cost and increases safety.

C-29
Features
Offers same features as industry-standard C-22, with the exception of the EG option.
C-29-ET has multiple lockdown screws in top-flange which retain the hanger and can be usedto energize the hanger packoff seal.
Bottom bowl preparations available are:
-S/FS-BG Seal Bushing -Integral Single or Double FS seal
-FS-BG bushing-PI pressure-intensified seal
-SBMS II metal-to-metal seal-RCMS (Rough Casing Metal Seal)
Benefits
Deeper bowl accepts C-29/C-129/C-229/C121-S extreme-load casing hangers in addition to other Surface Wellhead casing hangers.
The lockdown screws of the C-29-ET can also be used as bowl-protector hold-down screws.