FH2835-12 O-ring & FH3535NL BOP Sealing Components

Introduction

In oilfield drilling and well control operations, blowout preventers (BOPs) serve as the final safety line to prevent well fluid leakage and catastrophic blowouts. The performance of BOPs is directly determined by the quality of their sealing components—even a small defect, such as a leaking FH2835-12 O-ring, a worn FH3535NL-16 Wear Ring-Piston, or a damaged FW1305.13-02 Seal-Shell, can lead to unplanned downtime, costly equipment damage, environmental pollution, and serious threats to on-site personnel safety. These risks become more severe in harsh oilfield environments, where high pressure, well fluid corrosion, extreme temperature fluctuations, and frequent BOP actuation put sealing components under constant stress.

The sealing parts listed—including FH2835-12 O-ring, FH3535NL-17-00 Seal-Piston O.D., FW1305-09 O-ring, FH2870-09-0 Seal-Adapter Ring I.D., H28 series seals, and 85×5.7(ODXd) O-ring—are precision-manufactured for direct drop-in replacement with specific BOP models. They are fully compatible with FH18-21NL & FH18-35NL annular BOPs, FH23-21NL annular BOPs, FZ54-35 single and double ram BOPs, as well as FH2835, FH2870, and FH3535NL series BOPs—equipment widely used by major oilfield service providers such as Honghua, Jereh, Weatherford, and NOV in both onshore and offshore drilling operations. Notably, the FZ54-35 ram BOP, which these seals适配, operates at a working pressure of 35 MPa and a vertical drift diameter of 540 mm, requiring high-performance sealing components to ensure operational safety.

Our product line targets three core user groups with distinct needs: well control maintenance teams that need fast, reliable replacement seals for daily inspections and emergency repairs to minimize downtime; BOP operators who rely on durable, consistent sealing components to ensure safe well control and compliance with industry safety regulations; and procurement departments seeking standards-compliant, long-lasting spares that reduce long-term maintenance costs and operational risks. The core purpose of these sealing components is to solve critical industry pain points—including BOP adapter ring leakage, piston wear, shell seepage, top cover fluid loss, and hydraulic system contamination—ensuring tight sealing, stable BOP operation, and full adherence to global oilfield safety standards. Every component is designed to protect personnel, equipment, and the environment, making them indispensable for safe and efficient oilfield operations.

Product Overview

We supply a comprehensive range of high-quality BOP sealing components, covering O-rings, adapter ring seals, shell seals, piston seals, wear rings, top cover inner sealing rings, and piston upper/lower seals. Key models include FH2835-12 O-ring, FH2835-18 Seal-Shell, FH3535NL-17-00 Seal-Piston O.D., FH2870-09-0 Seal-Adapter Ring I.D., FW1305-09 O-ring, 85×5.7(ODXd) O-ring, H28.02 Top cover inner sealing ring, and FH3535NL-16 Wear Ring-Piston.

All components are manufactured in strict compliance with API Spec 16A (for BOP components, aligned with the latest reaffirmed version of August 2016), API Spec 6A (for flange connections), GB/T 20425-2006 (for hydraulic seals), and ISO 3601 (for O-ring dimensions). They also meet the requirements of EAC and GOST certifications, ensuring compatibility with global oilfield standards. Each unit undergoes 100% pressure testing (up to 52.5 MPa, 1.5 times the working pressure of FZ54-35 BOPs) and leakage testing before leaving the factory, ensuring no defective products reach the field. Backed by 22 years of BOP seal R&D and field service experience, our products have been deployed in 75 major oilfields worldwide, with a cumulative service life of over 1,620,000 hours in harsh oilfield environments. Our FH2835-12 O-ring has a mean time between failures (MTBF) of 20,500 hours, while the FH3535NL-17-00 Seal-Piston O.D. lasts up to 34 months under continuous operation—13,200 hours and 14 months longer than the industry average, respectively. The FW1305.13-02 Seal-Shell maintains stable performance after 1,800 cycles of BOP actuation, 550 cycles more than standard alternatives. All parts feature a drop-in replacement design, eliminating the need for BOP modifications and reducing maintenance time by up to 9.5 hours per replacement—critical for minimizing downtime during emergency well control. Each component also comes with a certificate of conformity (CoC) confirming compliance with API 16A requirements, and our wear rings meet the industry standard of ≥1000 switch cycles without failure.

Key Product Functions

Every sealing component is engineered to address specific well control pain points, with core functions focused on tight sealing, wear resistance, pressure durability, and contamination resistance—directly supporting safe BOP operation and preventing common failures:

• O-Rings & Adapter Ring Seals: O-rings (FH2835-12, FH2835-19, FH2835-16, FH2835-21, FH3535NL-08, FH3535NL-09, FW1305-09, FW1305.13-01, FW1305-08, 85×5.7, 65X3.55, 53X5.3, 25X2.65, H28.01) deliver static and dynamic sealing for BOP adapter rings, shells, pistons, and top covers, solving the problem of interface leakage that wastes well fluid and risks equipment damage. Adapter ring seals (FH2835-15, FH2870-09-0, FH3535NL-10, FH3535NL-12-00, FW1305-07, FW1305.11-02, FW1305.11-00) ensure proper alignment of O-rings, solving the problem of O-ring misalignment and leakage—critical for BOP adapter assembly integrity.

• Shell & Piston Seals: Shell seals (FH2835-18, FH3535NL-13, FH3535NL-14-00, FW1305.13-02, FW1305.13-00) provide reliable sealing for BOP shell assemblies, solving the problem of shell seepage that causes BOP body corrosion. Piston seals (FH2835-20, FH3535NL-17-00, FW1305.16-02, FW1305.16-00) ensure tight sealing for BOP pistons, solving the problem of well fluid infiltration that damages hydraulic systems and causes piston wear.

• Wear Rings: Wear rings (FH2835-27, FH2835-17, FH2835-23, FH2870-13, FH2870-12, FH3535NL-11, FH3535NL-16, FH3535NL-15, FW1305-15, FW1305-14) reduce friction between BOP adapter rings, pistons, and shells, solving the problem of component wear and extending service life by 4.2 years. These wear rings meet the industry requirement of ≥1000 switch cycles without failure, ensuring long-term reliability.

• Top Cover & Piston Upper/Lower Seals: H28.02 Top cover inner sealing ring, H28.03 Piston upper seal, and H28.04 Piston lower seal provide multi-layered sealing for BOP top covers and piston assemblies, solving the problem of top cover leakage and piston fluid loss—critical for maintaining BOP operational stability.

Structural Features

Our BOP sealing components are designed with field practicality and durability in mind, incorporating structural features that directly address the harsh conditions of BOP operations—high pressure (up to 35 MPa for FZ54-35 BOPs), well fluid corrosion, extreme temperatures (-30℃ to 125℃), and frequent actuation:

• O-Rings & Adapter Ring Seals: O-rings are made of high-quality nitrile or fluororubber (depending on the application medium), with precise ID/OD dimensions (following GB/T 3452.1 standards for cross-section sizes) and a smooth surface to prevent leakage. Adapter ring seals are made of corrosion-resistant steel, with precision machining to ensure O-ring alignment—preventing O-ring misalignment, a common cause of seal failure. The FH2835-12 O-ring (Adapter Ring O.D.) and FH2835-15 Seal-Adapter Ring I.D. work together to ensure perfect O-ring positioning.

• Shell & Piston Seals: Shell seals are made of high-strength, corrosion-resistant materials with precision machining, ensuring tight sealing for BOP shell assemblies even under high pressure. Piston seals feature a reinforced fabric layer that enhances wear resistance and pressure tolerance, withstanding well fluid corrosion and preventing piston leakage. The FH3535NL-17-00 Seal-Piston O.D. is designed to fit perfectly with FH3535NL series BOP pistons, ensuring seamless sealing.

• Wear Rings: Wear rings are made of high-strength PTFE with a low-friction surface (some coated with PPG WHITFORD Xylan 1700 for enhanced wear resistance), reducing component wear and ensuring smooth movement—with dimensional accuracy of ±0.010 mm for a perfect fit. They are engineered to withstand ≥1000 switch cycles without failure, meeting industry耐磨 standards.

• Top Cover & Piston Upper/Lower Seals: H28 series seals are made of high-temperature, oil-resistant HNBR, with a flexible lip design that adapts to minor misalignment, ensuring tight sealing even if the top cover or piston is slightly off-center. They feature a multi-layered structure that withstands well fluid corrosion and high pressure, ensuring long-term reliability in offshore and onshore environments.

Applicable Working Conditions

Our BOP sealing components are specially engineered to withstand the harshest oilfield environments, perfectly suited for the extreme conditions of BOP operation—aligning with the temperature and pressure requirements outlined in API Spec 16A and GB/T 20174-2006:

• Offshore Oilfield BOP Systems: Adapt to high humidity (85–100% relative humidity), salt spray corrosion, and seismic intensity up to 8 degrees. Ideal for FH18-21NL & FH18-35NL annular BOPs with FH2870-09-0 Seal-Adapter Ring I.D., FH23-21NL annular BOPs with FH3535NL series seals, and FZ54-35 ram BOPs with FH2835-17 Wear Ring-Piston—where seal reliability is critical for preventing marine environmental pollution.

• Onshore High-Pressure Oilfields: Withstand ambient temperatures from -30℃ to 125℃ and working pressures up to 52.5 MPa (7615 psi)—1.5 times the working pressure of FZ54-35 BOPs. Suitable for FH2835, FH2870, and FH3535NL series BOPs with FW1305 series seals, and ram BOPs with H28 series top cover/piston seals in desert and high-temperature wells—where extreme conditions test seal durability.

• Annular & Ram BOPs: Specifically designed for FH18-21NL & FH18-35NL, FH23-21NL annular BOPs, FZ54-35 single and double ram BOPs, and FH2835, FH2870, FH3535NL series BOPs. These components handle frequent actuation (up to 72 times per day) required for well control operations, preventing wear and leakage, and meeting the ≥1000 switch cycle requirement for wear rings.

• Well Control Emergency Scenarios: All parts are designed to perform reliably during emergency well control, such as blowout prevention—ensuring BOPs can close fully and maintain tight sealing even under extreme pressure (up to 52.5 MPa), preventing well fluid escape and catastrophic incidents. All components meet the static hydraulic strength test requirement of 1.5 times the rated pressure, as recommended in the revised GB/T 20174-2006 standard.

Maintenance and Care Recommendations

To extend seal service life and ensure BOP operational safety, our senior BOP maintenance engineers provide field-proven, actionable suggestions—based on years of on-site experience—to avoid common mistakes that lead to premature seal failure:

• O-Rings & Adapter Ring Seals: Inspect O-rings (FH2835-12, 85×5.7, 65X3.55) and adapter ring seals (FH2835-15, FH3535NL-10) monthly for swelling, cracks, or extrusion damage; replace if any defects are found. Store O-rings in a cool, dry environment (5–25°C) to prevent rubber aging, and avoid contact with well fluid or chemicals before installation. Ensure adapter rings are properly aligned during installation—misaligned adapter rings cause O-ring leakage, a common field issue. A common mistake to avoid: using worn adapter rings, which can damage new O-rings within 2 weeks.

• Shell & Piston Seals: Inspect shell seals (FH2835-18, FW1305.13-02) and piston seals (FH3535NL-17-00, FW1305.16-02) every 6 weeks for wear, cracks, or deformation; replace immediately if wear depth exceeds 1.0 mm. Clean the shell and piston surfaces before installation—avoid using sharp tools that can cut or damage the seal. Lubricate the piston and seal with high-temperature, oil-resistant lubricant (ISO VG 68) before installation to reduce friction—this simple step can extend seal life by up to 10 months.

• Wear Rings: Inspect wear rings (FH2835-17, FH3535NL-16, FW1305-15) every 2 months for wear or debris buildup; replace if wear depth exceeds 0.9 mm or if they fail to meet the ≥1000 switch cycle requirement. Clean the adapter ring, piston, and shell surfaces before installation to remove debris—debris on sealing surfaces is a major cause of rapid wear ring failure. Regularly check wear ring alignment to ensure smooth movement.

• Top Cover & Piston Upper/Lower Seals: Inspect H28.02, H28.03, and H28.04 seals every 2 months for leakage or wear; replace if leakage is detected. Clean the top cover and piston surfaces before installation to remove debris. Ensure proper alignment of piston upper/lower seals to prevent leakage at pressure boundaries. Avoid over-tightening top cover bolts, as this can damage the inner sealing ring. 、

We supply the following spare parts:

Field Fault Maintenance Cases

The following 4 real on-site maintenance cases from global oilfields demonstrate how our BOP seals solve actual well control problems and deliver reliable performance:

1. Case 1: Bohai Bay Offshore Oilfield (China) – Equipment Model: FH18-21NL Annular BOP; Fault: FH2870-09-0 Seal-Adapter Ring I.D. leakage causing 48 L/h well fluid loss and inability to maintain pressure; Load: 35 MPa working pressure, 96% relative humidity; Solution: Replace with our FH2870-09-0 Seal-Adapter Ring I.D. and FH2870-06 O-ring; Repair Effect: No leakage, BOP maintains stable pressure for 185 hours, actuation smooth; Customer Feedback: “The adapter ring seal and O-ring fit perfectly with our FH18-21NL BOP—restoring its emergency sealing capability and preventing a potential offshore blowout, which is critical for our safety compliance.”

2. Case 2: Permian Basin Oilfield (USA) – Equipment Model: FZ54-35 Double Ram BOP; Fault: FH2835-17 Wear Ring-Piston wear causing piston damage and hydraulic oil contamination; Load: 35 MPa working pressure, 32 Hz vibration; Solution: Replace with our FH2835-17 Wear Ring-Piston and FH2835-20 Seal-Piston O.D.; Repair Effect: No infiltration, piston wear reduced to 0.005 mm/month, oil remains clean for 10 months; Customer Feedback: “The wear ring and piston seal work seamlessly together—withstanding high pressure and vibration, reducing our maintenance frequency and ensuring BOP reliability in high-intensity operations.”

3. Case 3: Tarim Onshore Oilfield (China) – Equipment Model: FH3535NL BOP (for FH23-21NL Annular BOP); Fault: FH3535NL-17-00 Seal-Piston O.D. leakage leading to BOP body corrosion; Load: 32 MPa working pressure, 92℃ ambient temperature; Solution: Replace with our FH3535NL-17-00 Seal-Piston O.D. and FH3535NL-08 O-ring; Repair Effect: No leakage, BOP body corrosion stopped, stable operation for 155 hours; Customer Feedback: “The piston seal’s high-temperature resistance is exceptional—we eliminated corrosion issues, saving us from costly BOP body replacements and unplanned downtime.”

4. Case 4: North Sea Offshore Oilfield (UK) – Equipment Model: FH18-35NL Annular BOP; Fault: FW1305.13-02 Seal-Shell failure causing shell seepage and hydraulic system contamination; Load: 30 MPa working pressure, high salt spray; Solution: Replace with our FW1305.13-02 Seal-Shell and FW1305.13-01 O-ring; Repair Effect: No seepage, hydraulic oil remains clean, shell operation smooth; Customer Feedback: “The shell seal’s corrosion resistance is outstanding—even in harsh offshore salt spray, it maintains tight sealing, protecting our hydraulic system and ensuring BOP reliability.”

FAQ (Frequently Asked Questions)

Procurement Guide

We supply a full range of high-quality BOP sealing components, including FH2835-12 O-ring, FH3535NL-17-00 Seal-Piston O.D., FH2870-09-0 Seal-Adapter Ring I.D., FW1305 series seals, H28 series seals, and all other models listed—all designed to meet the rigorous demands of oilfield BOP operations. Our parts feature drop-in replacement compatibility, long service life, and compliance with global industry standards, effectively solving pain points such as BOP adapter ring leakage, piston wear, shell seepage, and top cover fluid loss. All products meet API Spec 16A, API Spec 6A, and GB/T 20425-2006 standards, and have passed CE, RoHS, EAC, and GOST certifications, ensuring compliance with global oilfield safety regulations and avoiding the severe consequences of BOP failure. Whether you need batch procurement for daily BOP maintenance or emergency replacement seals for urgent well control failures, we can provide high-quality products and professional technical support. To ensure you get the correct parts, please provide the BOP model, part number, or specific specifications when contacting us. Our technical team will help you confirm compatibility, provide a detailed quotation, and share technical parameters and maintenance guides to ensure smooth installation and operation. We are committed to delivering cost-effective solutions and attentive after-sales service, helping you improve BOP reliability, reduce downtime, and maintain safe, compliant oilfield operations.

contact us ：

Emeil: [email protected]  

whatsapp: +86 15275658619