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.

• 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.

• 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

1. The BOP is designed and manufactured in accordance with API Spec 16A.
2. All internal components in contact with well fluids are resistant to sulfide stress corrosion, complying with NACE MR 0175/ISO 15156 (all parts).