Hydril GK Annular Blowout Preventer (BOP) Overview The Hydril GK Annular BOP is a versatile pressure control device
designed for surface installations, offshore platforms, and subsea
applications, boasting a proven track record of reliable
performance in the petroleum industry. It delivers safe and
efficient well control with tailored features and intuitive
operation. Key Features - Minimal moving parts: Only two core components (piston and packing
unit) reduce wear points, minimizing maintenance needs and
downtime.
- Stable long-piston design: A length-to-diameter ratio approaching 1
eliminates cocking and binding during operations with off-center
pipe or uneven sand/cutting accumulations.
- Conical bowl piston design: Acts as a sealing surface against the
rubber packing unit, avoiding metal-to-metal wear and extending
service life.
- Field-replaceable wear plate: Serves as an upper non-sealing wear
surface for the packing unit, enabling fast and cost-effective
on-site repairs.
- Dual head options: Screwed head design ensures secure body-head
connection with no loose parts; latched head (available for
13-5/8"-5000 psi and larger models) allows quick access to packing
units and seals.
- Durable sealing system: Large pressure-energized seals dynamically
seal piston chambers, ensuring long seal life and low maintenance.
- Rigorous testing and compliance: Operating chambers are tested to
full working pressure; meets NACE MR-01-75 standards for resistance
to sulfide stress cracking.
- Flexible packing unit options: Two rubber compound choices (natural
rubber and nitrile rubber) adapt to diverse drilling conditions.
Operation Principles - Basic actuation: Requires both opening and closing hydraulic
pressure. Seal-off is achieved by applying hydraulic pressure to
the closing chamber, which raises the piston and forces the packing
unit into sealing engagement with the drill string or open bore.
- Well pressure assistance: After initial seal-off, well pressure
helps maintain the seal (excluding GK 7-1/16"-15,000 and 20,000 psi
models, which require sustained closing pressure).
- Stripping operations: Drill pipe can be rotated and tool joints
stripped through the closed packing unit while maintaining a seal.
Optimal packing unit life is achieved by setting the closing
chamber pressure to allow slight drilling fluid leakage for
lubrication.
- Control system compatibility: Works with any standard closing unit
equipped with a separate pressure regulator valve for the annular
BOP and sufficient accumulator volume.
- Supplementary components: If the pressure regulator valve responds
slowly, an accumulator (surge absorber) precharged to 50% of the
required closing pressure should be installed in the closing
chamber control line. For subsea operations, an accumulator in the
opening chamber line may be added to prevent pressure fluctuations
| Item | Annular Blowout Preventer (BOP) | |
|---|
| Model | FHZ28-35 | FHZ28-35/70 | | Weight (kg) | 4000 | 4110 | | Height (H, mm) | 1240 | 1290 | | Center of Gravity Height (h, mm) | 703 | 727 | | Top Connection Type | 11"-5000 psi 6B R54 | 11"-5000 psi 6B R54 | | Bottom Connection Type | 11"-5000 psi 6B R54 | 11"-10000 psi 6BX BX158 | | Bore Size | 279.4 mm (11″) | 279.4 mm (11″) | | Hydrostatic Test Pressure | 51.8 MPa (75,000 psi) | 51.8 MPa (75,000 psi) | | Rated Working Pressure | 34.5 MPa (5,000 psi) | 34.5 MPa (5,000 psi) | | Hydraulic Control System Strength Working Pressure | 31.4 MPa (4,500 psi) | 31.4 MPa (4,500 psi) | | Hydraulic Control Rated Working Pressure | 20.7 MPa (3,000 psi) | 20.7 MPa (3,000 psi) | | Recommended Hydraulic Operating Pressure | 8.3-10.4 MPa (1,200～1,500 psi) | 8.3-10.4 MPa (1,200～1,500 psi) | | Packing Unit Sealing Range | 0~279.4 mm (0~11") | 0~279.4 mm (0~11") | | Oil Volume for One Packing Unit Opening | 31 L | 31 L | | Oil Volume for One Packing Unit Closing | 37.5 L | 37.5 L | | Hydraulic Control Line Connection Thread | NPT 1" | NPT 1" | | Temperature Class | T-20/250 (Subject to change per specific contract) | T-20/250 (Subject to change per specific contract) |
Notes: - The BOP is designed and manufactured in accordance with API Spec
16A.
- All internal components in contact with well fluids are resistant
to sulfide stress corrosion, complying with NACE MR 0175/ISO 15156
(all parts).
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