1. Core Introduction & Application
The FH Series NL Annular Blowout Preventers (BOPs) include models FH1821NL, FH1835NL, FH1835/70NL, FH2321NL, FH2821NL, FH2835NL, FH2835/70NL, FH3521NL, FH3535NL, and FH3535/70NL. Designed for oil/gas drilling well control, they meet API Spec 16A and NACE MR-0175 standards, suitable for H₂S-containing environments. Tailored for offshore/onshore drilling contractors and well maintenance teams, they seal wellbores of various sizes to prevent blowouts.
1.1 Product Features & Functional Advantages
This series adopts spherical sealing packers and flange-connected bonnet-shell structures, ensuring reliable sealing under rated pressures (21-35MPa). Metal parts have T-20 temperature resistance, nonmetals meet BB grade, and hydraulic control connections (NPT 1"-1 1/2") enable efficient actuation. They adapt to diverse wellbore fluids and offer quick maintenance, reducing downtime in critical operations.
1.2 Applicable Working Conditions
Suitable for onshore/offshore vertical, directional, and horizontal drilling. Operates at -20℃ to 60℃, withstands hydrostatic test pressures up to 52.5MPa, and handles H₂S-containing formation fluids. Bore sizes (179.4mm-346.1mm) match standard drill pipes/casings, widely used in medium-deep wells and high-corrosion oilfields.
1.3 Maintenance Recommendations
Conduct API 16A-compliant hydrostatic tests annually. Replace seals/wear rings every 6-12 months; use genuine parts only. Lubricate hydraulic components with compatible fluids (ISO VG 46). Store parts in dry, corrosion-free environments. Inspect packers and seals for cracks before each use to avoid leakage.
2. Classified Parts List & Technical Details
2.1 Main Body Structural Components
These core parts form the BOP’s framework, withstanding high pressure and corrosion. Forged steel construction ensures structural stability, solving deformation issues. Critical for maintaining seal integrity in high-pressure well control scenarios.
No. | Description | Model & Part No. (Qty) | Material/Standard | Main Wear Causes | Damage Prevention Notes |
1 | Bonnet | FH1821NL-01(1); FH1835NL-01(1); FH2321NL-01(1); FH2821NL-02(1); FH2835NL-02(1); H07.02(1); H32.01(1); FH3535NL-04(1) | Forged alloy steel, API 16A, NACE MR-0175 | Flange bolt loosening; H₂S corrosion; impact during transportation | Retorque studs quarterly; apply anti-corrosion coating; use protective covers during storage |
2 | Shell | FH1821NL-02(1); FH1835NL-13(1); H08.01(1); FH2321NL-14(1); FH2821NL-01(1); FH2835NL-01(1); H07.01(1); H32.02(1); FH3535NL-01(1); FH3535/70NL-01(1) | Forged steel Q355B, H₂S-resistant | Wellbore fluid erosion; pressure surges; low-temperature brittleness | Avoid overpressure (≤rated 35MPa); preheat to ≥-10℃ in cold environments; flush after H₂S service |
3 | Piston | FH1835NL-14(1); FH2321NL-07(1); FH2821NL-16(1); FH2835NL-09(1); FH3535NL-02(1) | Hard chrome-plated carbon steel, GB/T 1184-1996 | Hydraulic fluid contamination; reciprocating wear; seal friction | Filter hydraulic fluid (≥10μm); replace wear rings promptly; use compatible hydraulic oil |
4 | Adapter Ring | FH1835NL-05(1); FH2321NL-06(1); FH2821NL-07(1); FH2835NL-08(1); FH3535NL-03(1) | Alloy steel, precision-machined | Radial pressure deformation; seal groove wear; debris accumulation | Inspect groove dimensions monthly; clean before assembly; maintain proper seal compression |
2.2 Sealing Components
These parts ensure zero leakage of wellbore fluids, resisting H₂S and high pressure. Comply with API 16A, solving seal hardening/tearing issues. Critical for maintaining well control integrity in corrosive environments.
No. | Description | Model & Part No. (Qty) | Material/Standard | Main Wear Causes | Damage Prevention Notes |
1 | Packer (Spherical) | FH1835NL.02-00A(1); FH2321NL-02(1); FH2821NL.05-00(1); FH2835NL-03.00A(1); FW1305.06-00A(1) | Nitrile rubber (NBR), BB temperature grade, H₂S-resistant | Abrasion from drill pipe; chemical degradation; high-temperature hardening | Replace every 500 actuation cycles; avoid contact with sharp objects; store away from UV light |
2 | Seal-Adapter Ring I.D. Upper | FH1835NL-06(1); FH2321NL-10(1); FH2821NL-09(1); FH2835NL-10(1); FH3535NL-10(1) | Fluororubber (FKM), API 16A | Compression set; H₂S corrosion; misalignment during assembly | Use torque wrenches for uniform compression; replace if hardness >80 Shore A; align before installation |
3 | Seal-Adapter Ring I.D. Lower | FH1835NL-10(1); FH2321NL.11-00(1); FH2821NL.10-00(1); FH2835NL.11-00(1); FH3535NL-12-00(1) | FKM, oil-resistant | Fluid erosion; wear from adapter ring; temperature fluctuations | Inspect for cracks monthly; maintain operating temp ≤60℃; clean mating surfaces |
4 | Seal-Piston O.D. | FH1835NL-16(2); FH2321NL.15-00(2); FH2821NL.15-00(2); FH2835NL.15-00(2); FH3535NL-17-00(2) | NBR, high-pressure resistant | Piston reciprocation wear; hydraulic fluid contamination; overpressure extrusion | Filter hydraulic fluid regularly; operate at 8.4-10.5MPa (recommended pressure); replace with wear rings |
5 | Seal-Shell Upper/Lower | Upper: FH1835NL-09(1), FH2321NL-09(1), FH2821NL.11(1), FH2835NL-12(1), FH3535NL-13(1); Lower: FH1835NL-11-00(1), FH2321NL.12-00(1), FH2821NL.12-00(1), FH2835NL.13-00(1), FH3535NL-14-00(1) | FKM, NACE MR-0175 | Shell-piston friction; H₂S degradation; improper installation | Lubricate before assembly; avoid over-tightening; replace after H₂S exposure |
6 | O-ring | FH1835NL-04(1)/07(1); FH2321NL-05(1)/08(1); FH2821NL-06(1)/08(1); FH2835NL-06(1)/07(1); FH3535NL-08(24)/09(24) | NBR, GB/T 3452.1-2005 | Hardening from aging; extrusion in gaps; chemical corrosion | Replace annually; store in dry, cool environments; ensure proper groove fit |
2.3 Wear Components
These parts reduce friction between moving components, preventing premature wear of pistons, shells, and adapters. Made of high-strength polymers, they extend BOP service life in high-reciprocation scenarios.
No. | Description | Model & Part No. (Qty) | Material/Standard | Main Wear Causes | Damage Prevention Notes |
1 | Wear Ring-Adapter Ring | FH1835NL-08(1); FH3535NL-11(1) | Polyoxymethylene (POM), self-lubricating | Radial pressure wear; debris abrasion; temperature deformation | Inspect wear monthly; replace if thickness <5mm; clean adapter ring surfaces |
2 | Wear Ring-Piston O.D. | FH1835NL-15(2); FH2321NL-16(2); FH2821NL-14(2); FH2835NL-16(2); FH3535NL-16(2) | Nylon 66, glass fiber reinforced | Piston reciprocation; hydraulic fluid contamination; misalignment | Maintain 0.1-0.2mm clearance; filter hydraulic fluid; align piston during assembly |
3 | Wear Ring-Shell | FH1835NL-12(1); FH2321NL-13(1); FH2821NL-13(1); FH2835NL-14(1); FH3535NL-15(1) | Polyetheretherketone (PEEK), high-strength | Shell-piston friction; high-pressure deformation; chemical erosion | Lubricate with high-temperature grease; avoid overpressure; replace every 12 months |
2.4 Fasteners & Accessories
These parts ensure secure assembly of BOP components, resisting vibration and pressure-induced loosening. Compliant with API standards, they prevent structural disassembly in high-pressure drilling scenarios.
No. | Description | Model & Part No. (Qty) | Material/Standard | Main Wear Causes | Damage Prevention Notes |
1 | Stud | FH1835NL-03(24); FH2321NL-04(22); FH2821NL-03(24); FH2835NL-05(24); FH3535NL-06(24) | Alloy steel grade 8.8, galvanized, NACE MR-0175 | Vibration loosening; H₂S corrosion; over-tightening damage | Torque to 220-250N·m; retorque after 100 operating hours; apply anti-seize paste |
2 | Cap Nut | FH2321NL-03(24/22); FH2821NL-04(24); FH2835NL-04(24); FH3535NL-05(24) | Carbon steel, heat-treated | Wrench damage; corrosion; thread wear | Use properly sized wrenches; clean threads before assembly; store with thread protectors |
3 | Plug | FH2835-22(2); FH3535NL-18(2) | Carbon steel, NPT thread | Thread sealant failure; corrosion; vibration loosening | Replace thread sealant monthly; tighten to 150-180N·m; inspect for leakage |
4 | Adapter Substitute | FHZ5414-10(2) (FH3535/70NL) | Alloy steel, precision-machined | Misalignment; pressure deformation; debris accumulation | Align before installation; clean thoroughly; inspect for cracks annually |
3. On-Site Fault Repair Cases
Case 1: FH2835NL BOP Packer Leakage
Scenario: Leakage at the spherical packer during well control operations. Root Cause: Packer (FH2835NL-03.00A) abrasion from drill pipe and H₂S corrosion, violating NACE MR-0175 standards. Repair: Replaced the packer with a genuine part, cleaned the adapter ring, and applied lubricant. Prevention: Replace packers every 6 months in H₂S wells; inspect for wear before each use.
Case 2: FH1835NL BOP Piston Seal Failure
Scenario: Hydraulic cylinder failed to actuate the piston, causing incomplete wellbore sealing. Root Cause: Damaged piston O.D. seals (FH1835NL-16) due to overpressure (exceeding 21MPa) and contaminated hydraulic fluid. Repair: Replaced seals and hydraulic oil, installed a pressure relief valve. Prevention: Operate at 8.4-10.5MPa; filter hydraulic fluid every 3 months.
4. FAQ
Question | Answer |
Are FH series NL BOP parts interchangeable across models? | No. Parts are model-specific (e.g., packers, seals). Interchangeability causes mismatches in bore size/pressure rating, leading to leakage. Use only parts specified for each model (e.g., FH1835NL parts for FH1835NL BOP). |
How to select hydraulic fluid for FH NL BOPs? | Use ISO VG 46 hydraulic oil compatible with NBR/FKM seals, meeting API 670 standards. Avoid oil containing impurities or incompatible additives, which degrade seals and damage hydraulic components. |
What is the service life of spherical packers in H₂S environments? | In H₂S-containing wells (complying with NACE MR-0175), packers last 6-8 months under normal operation. Proactive replacement every 6 months is recommended to avoid sudden failure and ensure well control safety. |
5. Procurement Guidance & Call to Action
FH Series NL Annular BOPs and genuine parts meet API Spec 16A and NACE MR-0175 standards, ensuring reliable performance in high-pressure, H₂S-containing oilfield environments. Our parts are precision-manufactured to match original equipment specifications, eliminating compatibility risks and minimizing downtime.
We provide personalized support, including part compatibility verification, H₂S service maintenance consulting, and technical guidance. Genuine parts—from packers to fasteners—ensure your BOP maintains regulatory compliance and operational safety.
Choose genuine FH NL BOP parts to safeguard your drilling operations and extend equipment service life. Contact us today to discuss your specific model requirements, spare part needs, or technical inquiries. Our team will tailor a solution aligned with your well control goals and environmental conditions.
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