Shaffer Bolt-Cover Spherical Blowout Preventer (BOP)
The Shaffer Bolt-Cover Spherical BOP is a high-reliability annular pressure control equipment designed for oil and gas drilling operations. As essential well control equipment, it provides stable sealing and pressure control during drilling, tripping, and well intervention processes, effectively mitigating blowout risks to protect personnel, equipment, and the environment.
Key Applications
- Well Pressure Containment: Acts as frontline defense against unexpected wellbore pressure surges, forming tight seals to prevent blowouts
- Universal Sealing Compatibility: Seals reliably on various downhole tools including kellys, drill pipes, tool joints, drill collars, casing, and wireline tools
- Pressurized Tripping Operations: Enables safe tripping of drill strings in and out of the wellbore under pressure
- Harsh Environment Adaptability: Suitable for internal H₂S service as standard, with straightforward conversion for external H₂S service; Arctic models available for low-temperature API 16A requirements
Core Advantages
Compact & Space-Saving Design
- Height is 15-20% lower than comparable annular BOPs, ideal for installations with limited vertical space
- Simplified structure reduces overall footprint without compromising performance
Efficient & Cost-Effective Operation
- Operates at low hydraulic pressure of 1,500 psi, reducing required accumulator size and associated costs
- Minimal hydraulic connections (only two for opening and closing) simplify system integration
Durable & Low-Maintenance
- Wear rings on moving parts eliminate metal-to-metal contact, extending component service life
- Wiper seals and wide clearances prevent debris accumulation and accelerate wear
- Rugged sealing element with steel reinforcement maintains reliable performance for 2-4 times longer than conventional elements
Easy Servicing & Field Adaptability
- Upper housing lifts off easily for access to internal components
- Adapter ring shields hydraulic systems from mud and grit during maintenance
- No complex tools required for routine servicing, minimizing downtime
Operation Procedures
Basic Closure & Opening
Closing: Apply hydraulic pressure (max 1,500 psi) to actuate the piston, driving the sealing element in smooth upward and inward motion to seal the wellbore.
Opening: Release closing pressure and apply opening hydraulic pressure to retract the piston, allowing the sealing element to return to its open position automatically.
Stripping Operations
- Close BOP with maximum 1,500 psi hydraulic pressure
- Prior to stripping, reduce closing pressure to allow slight leak for lubrication and temperature control
- Maintain slight leakage if conditions permit; gradually increase pressure as element wears
- If leakage is prohibited, set pressure just enough to maintain tight seal
- Switch to alternate preventer when required closing pressure approaches 1,500 psi
Safety & Operational Notes
- Ensure BOP is rated for well's working pressure and fluid conditions
- Regularly inspect sealing element for wear; replace if leakage exceeds acceptable limits
- Comply with API 16A (Fourth Edition, 2017) and NACE MR0175 standards
- Use oil (not grease) on piston and cylinder during reassembly
Technical Specifications
Bore Sizes: 4½ inches to 30 inches (varies by model)
Working Pressure Ratings: 1,000 psi, 2,000 psi, 3,000 psi, 5,000 psi, and 10,000 psi
Temperature Range: Standard models (nitrile element): 40°F to 180°F (4°C to 82°C); low-temperature Arctic models available
Sealing Element Options: Nitrile (blue) and natural rubber (red) for different service conditions
| Item |
Annular BOP |
| Model |
Model S 11″-5000psi |
| Weight |
4518 kg |
| Height |
1064 mm |
| Drift diameter |
279.4mm / 11" |
| Hydrostatic test pressure |
51.8Mpa (7,500psi) |
| Rated working pressure |
34.5 Mpa (5,000psi) |
| Hydraulic control rated working pressure |
13.8Mpa (2,000psi) |
| Recommended hydraulic control working pressure to seal pipe |
≤10.5Mpa (≤1,500psi) |
| Max. working pressure to close open hole |
17.5Mpa (2,500psi) |
| Max. open volume |
72L |
| Max. close volume |
74L |
| Shackle lifting weight (t) |
17t |
| Specification for hydraulic oil outlet connection |
NPT 1〞 |
| Temperature rating of non-metallic seals |
BGB (-18℃～93℃) |
| Temperature ratings for metallic materials |
T-20/250 (-29℃~+121℃) |
| Dielectric materials in contact wells |
Meet the requirements of NACE MR0175 |
Note: BOP should be designed and manufactured according to API Spec 16A. All metallic materials which come in contact with well fluids shall meet the requirements of NACE MR0175 for sour service.
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