Hydril Annular Blowout Preventer (BOP) Overview

Hydril Annular BOP is a multipurpose pressure control equipment designed for surface rigs, offshore platforms, and subsea applications, has an excellent record of reliable performance in the petroleum industry. It delivers safe and efficient well control with customize features and convenient operation.

Key Features

1. fewer moving parts: Only two key components (piston and packing element) reduce wear points, minimizing maintenance needs and downtime.
2. Stable long-piston design: The piston has a length-to-diameter ratio nearly 1. And the design could eliminate the cocking and binding during operations with off-center drill pipe or uneven sand/cutting accumulations.
3. Conical bowl piston design: Acts as a sealing surface against the rubber packing element, avoiding metal-to-metal wear and extending service life.
4. Field-replaceable wear plate: Serves as an upper non-sealing wear surface for the packing element, enabling fast and cost-effective on-site repairs.
5. 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 the larger models) allows quick access to packing elements and seals.
6. Durable sealing system: Large pressure-energized seals dynamically seal piston chambers, ensuring long seal life and low maintenance.
7. Rigorous testing and compliance: Operating chambers are tested to full working pressure; meets NACE MR-01-75 standards for resistance to sulfide stress cracking.
8. Flexible packing element options: Two rubber compound choices (natural rubber and nitrile rubber) adapt to different drilling conditions.

Operation Principles

1. 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 element into sealing engagement with the drill pipes or open bore.
2. Well pressure assistance: After initial seal-off, well pressure helps maintain the seal (excluding 7-1/16"-15,000 and 20,000 psi models, which require sustained closing pressure).
3. Stripping operations: Drill pipe can be rotated and tool joints stripped through the closed packing element while maintaining a seal. Optimal packing element life is achieved by setting the closing chamber pressure to allow slight drilling fluid leakage for lubrication.
4. Control system compatibility: Works with any standard accumulator unit equipped with a separate pressure regulator valve for the annular BOP and sufficient accumulator volume.
5. 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.