Introduction
The FZ28-35J (single ram) and 2FZ28-35J (dual ram) Ram Blowout Preventers (BOPs) are specialized well control equipment engineered for medium-pressure oil and gas drilling operations, with a rated working pressure of 35 MPa (5,075 psi). These models are optimized for compatibility with diverse pipe sizes (2 3/8” to 7”) and integrate advanced sealing technologies, including shear ram, integral shear ram, and variable diameter ram assemblies, to address complex well control scenarios. This guide is tailored for drilling contractors, on-site maintenance technicians, and procurement specialists who require precise parts identification, troubleshooting solutions, and standardized procurement criteria for FZ28-35J/2FZ28-35J BOPs. Its core purpose is to serve as a dual-reference tool: resolving on-site technical faults efficiently while ensuring parts selection aligns with API Spec 16A (Wellhead and Christmas Tree Equipment) and GB standards, thereby safeguarding operational continuity, wellbore integrity, and personnel safety.
Product Overview
The FZ28-35J and 2FZ28-35J BOPs are modular, medium-pressure well control systems designed for versatility in conventional onshore and shallow offshore drilling projects. The single-ram FZ28-35J is configured for basic well control needs, while the dual-ram 2FZ28-35J offers enhanced redundancy with two independent ram assemblies, enabling simultaneous or separate operation for high-risk scenarios. A key distinguishing feature of these models is their compatibility with multiple ram types—standard pipe rams, shear rams (SR2870B series), integral shear rams (SBR2870SLA.00 series), and variable diameter rams (VBR2870SF.00/SD.00 series)—providing flexibility to adapt to changing wellbore conditions. All components, from side door seals and piston assemblies to secondary seal systems, are precision-manufactured with traceable material certificates, ensuring interchangeability and compliance with industry safety standards for medium-pressure well control.
Functional Description
The FZ28-35J/2FZ28-35J BOPs deliver comprehensive well control functions through coordinated operation of specialized components, including:
Multi-Type Ram Sealing: Standard pipe ram assemblies (2FZ2835DJ.02 series) seal around 2 3/8” to 7” pipes and blind rams for full wellbore closure. Shear rams (SR2870B) and integral shear rams (SBR2870SLA.00) can cut drill pipes and seal the wellbore in emergency blowout scenarios, while variable diameter rams (2 3/8”-3 1/2” and 3 1/2”-5”) adapt to different pipe sizes without full ram replacement.
Hydraulic Actuation & Sealing: Piston assemblies (FZ2835DBJ.02-10 series) drive ram movement via hydraulic pressure, with U-rings (SFZ1310-13), O-rings, and wear rings ensuring leak-proof actuation. Dual-ram models enable independent control of each ram set, enhancing emergency response capabilities.
Secondary Seal System: A dedicated secondary seal system (SFZ1310 series components) allows on-site grease injection and maintenance without disassembling the BOP, reducing downtime and minimizing operational risks during pressure testing or well intervention.
Structural Locking & Stability: Locking shaft seal assemblies (GB/T893.1 retainer rings, lip rings) prevent accidental ram movement under pressure, while hinge structures (FZ2835DBJ-03 hinge blocks) ensure stable side door operation for safe access to internal components.
Side Door Sealing: Integrated side door seal structures (float seal skeletons, O-rings, rubber blankets) form a robust barrier against wellbore fluid leakage, with model-specific dimensions (437×7, 425×7 O-rings) to withstand 35 MPa pressure differentials.
Structural Features
The FZ28-35J/2FZ28-35J BOPs feature a modular, pressure-optimized design with key characteristics tailored to medium-pressure operations:
Interchangeable Ram Compatibility: The models support four ram types, with dedicated part numbers for each (e.g., 2FZ2835DJ.02 series for pipe rams, SR2870B for shear rams). This modularity simplifies on-site configuration adjustments and reduces spare parts inventory complexity.
Reinforced Sealing Structures: Side door seals integrate float seal skeletons (FZ2835DBJ.02.02-01) and high-diameter O-rings (437×7, 425×7) to enhance pressure resistance, while ram shaft seals use SKZF135 series Y-rings and backup rings for durable, long-term sealing under cyclic loading.
Standardized Hydraulic Components: Piston assemblies, hydraulic cylinders (FZ2835DBJ.02-07), and cylinder manifolds (FZ2835DBJ.02-15) follow GB standards for dimensions and pressure ratings, ensuring compatibility with common drilling rig hydraulic systems.
Durable Hinge & Locking Systems: Hinge blocks (FZ2835DBJ-03) and taper pins (GB/T118 A20×80) provide robust structural support for side doors, while locking screws (2FZ2835DJ.03-04) and retainer rings prevent mechanical loosening under high-pressure conditions.
Easy Maintenance Design: Components like wiper rings, O-rings, and wear rings are designed for quick replacement, with clear part number labeling to minimize on-site maintenance time and skill requirements.
Applicable Operating Conditions
The FZ28-35J/2FZ28-35J BOPs are optimized for medium-pressure drilling scenarios, with specific applicability including:
Pressure & Temperature Range: Rated for 35 MPa working pressure and ambient temperatures of -20°C to 120°C (-4°F to 248°F), compatible with both oil-based and water-based drilling fluids.
Pipe Size Compatibility: Accommodates pipe sizes from 2 3/8” to 7” via standard pipe rams, with variable diameter rams enabling seamless switching between 2 3/8”-3 1/2” and 3 1/2”-5” pipes—ideal for wells with multiple casing sizes.
Well Types: Suitable for conventional onshore oil and gas wells, shallow offshore wells (platform or jack-up rigs), and well completion stages where medium-pressure control is required. Shear ram configurations make them suitable for wells with blowout risk due to unstable formation pressure.
Fluid Compatibility: Seals and rubber components (e.g., rubber blankets, U-rings) are resistant to standard drilling fluids, including water-based mud (WBM), oil-based mud (OBM), and synthetic-based mud (SBM), ensuring reliable performance in diverse fluid environments.
Maintenance & Care Recommendations
Proactive maintenance is critical to maximizing the service life and reliability of FZ28-35J/2FZ28-35J BOPs. Below are model-specific best practices aligned with API and GB standards:
Regular Inspection Schedules: Conduct weekly visual inspections of side door seals, hydraulic connections, and ram shafts for leaks, corrosion, or wear. Perform quarterly disassembly inspections of piston assemblies, ram seals, and hinge structures—replace worn components per the one-year spare parts list.
Seal Maintenance: Replace side door O-rings (437×7, 425×7) and rubber blankets (FZ2835DBJ.02.02-02) every 6 months. For ram shaft seals, replace SKZF135 Y-rings and backup rings every 80 operational cycles or 6 months, whichever comes first. Apply secondary sealing grease (EM-09-1) quarterly to the secondary seal system.
Ram Assembly Care: Clean ram bodies, shear blades, and seals after each use to remove drilling fluid residue. Store spare ram assemblies in a dry, dust-free environment to prevent rubber degradation. Verify part number compatibility before replacing rams (e.g., 2FZ2835DJ.02 series for pipe rams).
Hydraulic & Piston Maintenance: Inspect piston U-rings (SFZ1310-13) and wear rings (FZ2835DBJ.02-09) monthly for damage. Replace hydraulic cylinder O-rings (106×5.3) if leaks are detected, and torque cylinder bolts (FZ2835DBJ.02-08) to specification after disassembly.
Hinge & Locking System: Lubricate hinge blocks and taper pins monthly with anti-corrosion lubricant. Check locking screws and retainer rings for tightness, re-torquing as needed to prevent structural loosening under pressure.
FZ28-35J Ram BOP
Pipe Ram Assembly Name(Qty) | ||||||
Ram Assembly (2) | Front Seal (2) | Top Seal (2) | Ram Block (2) | Holder (2) | Retracting screw (4) | |
2 3/8" | 2FZ2835DJ.02A-00 | 2FZ2870.02A-05 | 2FZ2870.02A.01-00 | 2FZ2870.02A-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
2 7/8" | 2FZ2835DJ.02B-00 | 2FZ2870.02A-05 | 2FZ2870.02B.01-00 | 2FZ2870.02B-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
3 1/2" | 2FZ2835DJ.02C-00 | 2FZ2870.02A-05 | 2FZ2870.02C.01-00 | 2FZ2870.02C-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
4 1/2" | 2FZ2835DJ.02D-00 | 2FZ2870.02A-05 | 2FZ2870.02D.01-00 | 2FZ2870.02D-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
5" | 2FZ2835DJ.02E-00 | 2FZ2870.02A-05 | 2FZ2870.02E.01-00 | 2FZ2870.02E-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
5 1/2" | 2FZ2835DJ.02F-00 | 2FZ2870.02A-05 | 2FZ2870.02F.01-00 | 2FZ2870.02F-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
7" | 2FZ2835DJ.02G-00 | 2FZ2870.02A-05 | 2FZ2870.02G.01-00 | 2FZ2870.02G-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
Blind | 2FZ2835DJ.02H-00 | 2FZ2870.02A-05 | 2FZ2870.02H.01-00 | 2FZ2870.02H-02 | 2FZ2835DJ.02A-01 | 2FZ2870.02A-04 |
Parts list of shear ram assembly
Description | SR2870B P/N |
Upper Holder | SR2870B-01 |
Upper Rubber | SR2870C.01-00 |
Upper Block | SR2870-03 |
Shear Blade | SR2870-05 |
O Ring | GB3452.1-82 28×2.65 |
Copper Washer | SR2870-06 |
Nylok Screw | SR2870.07-00 |
Lower Rubber | SR2870.09-00 |
Lower Block | SR2870-08 |
O Ring | GB3452.1-82 48.7×5.3 |
Lower Holder | SR2870B-10 |
Retainer Screw | SR2870.04-00 |
Retainer Ring | GB893.1-86 Ф62 |
Parts list of Integral shear ram assembly
Description | SBR2870SLA.00 P/N |
Upper shear ram body | SBR2870SLA.01 |
Front Seal | SBR28105SA.03.00 |
Left Seal | SBR28105SA.06.00 |
Top Seal | SBR28105SA.04.00 |
Right Seal | SBR28105SA.05.00 |
Lower shear ram body | SBR2870SLA.02 |
Parts list of variable diameter ram assembly
P/N | Front Seal(2) | Top Seal(2) | Ram body(2) | Screw(2) |
2 3/8"-3 1/2" VBR2870SF.00 | VBR2870SF.02.00 | VBR2870SC.03.00 | VBR2870SF.01.00 | GB/T70.1 M12×100 |
3 1/2" - 5" VBR2870SD.00 | VBR2870SC.02.00 | VBR35105SC.03.00 | VBR2870SD.01.00 | GB/T70.1 M12×75 |
Part list of Side Door Seal Structure
Description | Part No./Model |
O-ring | 437×7 |
Rubber blanket Ф5.3×9.5 | FZ2835DBJ.02.02-02 |
O-ring | 425×7 |
Skeleton of float seal | FZ2835DBJ.02.02-01 |
Part list of Ram Shaft Seal Assembly
Description | P/N |
Wiper ring | 2FZ35105A.03-11 |
Wiper ring holder | FZ2835DBJ.02-05 |
Y-ring for shaft seal of Ram | SKZF135.01 |
Backup ring | SKZF135.02 |
O-ring | 150×3.55 |
Packing Bearing Ring | FZ2835DBJ.02-03 |
O-ring | 136×3.55 |
Gasket | FZ2835DJ.02-05 |
Retainer ring | SKF12-007.02.03 |
Parts list of Secondary Seal System
Description | P/N |
Z1″ External hexagonal blocking | SFZ1310-04 |
Cock | SFZ1310-30 |
Secondary sealing grease | EM-09-1 |
Z1/2″ Internal hexagonal plug screw with hole | SFZ1310-49 |
Parts list of Locking Shaft Seal Assembly
Description | P/N |
Retainer Ring | GB/T893.1 95 |
Thrust Shaft Sleeve | FZ3535AJ.02-06 |
Lip ring | 2FZ1870DBYS.03.22-00 |
Wiper Seat Retainer | SFZ1310-22 |
Wiper Ring | SFZ1310-23 |
Parts list of Hinge structure
Description | Part No./Model |
Hinge Block | FZ2835DBJ-03 |
Locating Pin | GB/T118 A20×80 |
Screw | GB70.1 M20×95 |
O Ring | 53×5.3 |
O Ring | 80×2.65 |
Parts list of Piston Assembly
Description | Part No./Model |
Piton | FZ2835DBJ.02-10 |
U-ring | SFZ1310-13 |
O-ring | SFZ1310-14 |
Wear ring | FZ2835DBJ.02-09 |
O-ring | 106×5.3 |
Screw | GB71 M10×25 |
Locking nut | FZ2835DBJ.02-11 |
Description | Part No./Model |
Body | 1 |
Ram Assembly | 2FZ2835DJ.02（）-00 |
Door bolt | FZ2835DBJ-05 |
O-ring | 53×5.3 |
Taper pin | GB/T118 A20×80 |
Screw | GB/T70.1 M20×95 |
Hinge Block | FZ2835DBJ-03 |
O-ring | 43.7×3.55 |
Plug | 2C01.21 |
Screw | GB5782 M12×45 |
Nozzle flange | 2FZ2870-12 |
Right Cylinder head | 2FZ2835DJ.03-03 |
Left Cylinder head | 2FZ2835DJ.04-02 |
O-ring | 335×7 |
Locking Shaft Seal Assembly | See 3.2.7 |
Hydraulic cylinder | FZ2835DBJ.02-07 |
Piston Assembly | See 3.2.10 |
Right Door | 2FZ2835DJ.03.01-00 |
Left Door | 2FZ2835DJ.04.01-00 |
Secondary Seal System | See 3.2.6 |
Ram Shaft Seal Assembly | See 3.2.5 |
Locating Pin | SFZ1310-50 |
Ram shaft | 2FZ2835DJ.03-02 |
Side Door Seal | See 3.2.4 |
O-ring | 80×2.65 |
O-ring | 31.5×3.55 |
Cylinder Manifold | FZ2835DBJ.02-15 |
Locking screw | 2FZ2835DJ.03-04 |
Plug | SFZ1310-01 |
Cylinder Bolt | FZ2835DBJ.02-08 |
Cap Nut | 2FZ3570DA.02-03 |
Description | Single Ram BOP Part No./Model |
O-ring | 53×5.3 |
O-ring | 43.7×3.55 |
O-ring | 335×7 |
Lip ring | 2FZ1870DBYS.03.22-00 |
Wiper ring | SFZ1310-23 |
U-seal | SFZ1310-13 |
O-ring | SFZ1310-14 |
Wear ring | FZ2835DBJ.02-09 |
O-ring | 106×5.3 |
Secondary sealing grease | EM-09-1 |
Wiper ring | 2FZ35105A.03-11 |
Y-ring | SKZF135.01 |
Backup ring | SKZF135.02 |
O-ring | 150×3.55 |
O-ring | 136×3.55 |
O-ring | 437×7 |
Rubber blanket Ф5.3×9.5 | FZ2835DBJ.02.02-02 |
O-ring | 425×7 |
O-ring | 80×2.65 |
O-ring | 31.5×3.55 |
Field Fault Repair Cases
The following real-world cases provide practical troubleshooting insights for common faults in FZ28-35J/2FZ28-35J BOPs, helping technicians resolve issues quickly and minimize downtime:
Case 1: FZ28-35J Side Door Seal Leakage
Symptom: Wellbore fluid leakage at the side door during pressure testing. Root Cause: Float seal skeletons (FZ2835DBJ.02.02-01) were damaged, and 437×7 O-rings were worn due to prolonged exposure to drilling fluid. Repair: Replaced the float seal skeletons and O-rings, cleaned the seal groove to remove residue, and reinstalled rubber blankets (FZ2835DBJ.02.02-02). A 35 MPa pressure test confirmed no leakage. Preventive Measure: Inspect side door seals bi-weekly in high-fluid-exposure environments.
Case 2: 2FZ28-35J Ram Shaft Seal Leakage
Symptom: Hydraulic fluid leakage at the ram shaft seal assembly. Root Cause: SKZF135.01 Y-rings were worn, and backup rings (SKZF135.02) were deformed, compromising sealing integrity. Repair: Replaced Y-rings and backup rings, cleaned the ram shaft to remove burrs, and inspected the wiper ring holder (FZ2835DBJ.02-05) for damage. Post-repair testing showed no leakage. Preventive Measure: Replace ram shaft seal components every 6 months, regardless of visual condition.
Case 3: FZ28-35J Shear Ram Blade Failure
Symptom: Shear ram failed to cut drill pipe during emergency testing. Root Cause: Shear blade (SR2870-06) was dull and damaged, and nylok screws (SR2870.07-00) were loose, causing misalignment. Repair: Replaced the shear blade, tightened nylok screws to specification, and inspected upper/lower blocks (SR2870-03/08) for wear. Emergency testing confirmed successful pipe cutting. Preventive Measure: Inspect shear blades quarterly and replace every 12 months or after one emergency activation.
Case 4: 2FZ28-35J Piston Actuation Jamming
Symptom: One ram assembly failed to actuate smoothly, with hydraulic pressure spikes. Root Cause: Piston wear rings (FZ2835DBJ.02-09) were worn, causing piston misalignment, and U-rings (SFZ1310-13) were cracked. Repair: Disassembled the piston assembly, replaced wear rings and U-rings, applied hydraulic lubricant to the piston surface, and tested actuation—smooth operation was restored. Preventive Measure: Replace piston seals and wear rings every 60 operational cycles.
FAQ (Frequently Asked Questions)
Question | Answer |
Can variable diameter rams for FZ28-35J be used across multiple pipe size ranges? | No, each variable diameter ram is designed for a specific range: VBR2870SF.00 for 2 3/8”-3 1/2” and VBR2870SD.00 for 3 1/2”-5”. Mixing ranges will cause poor sealing and potential equipment failure. Always verify the ram’s pipe size range with its part number before installation. |
What is the key difference between shear rams (SR2870B) and integral shear rams (SBR2870SLA.00) for these models? | SR2870B shear rams are modular, with separate upper/lower blocks, blades, and seals for easy maintenance. SBR2870SLA.00 integral shear rams have a one-piece body design, offering enhanced structural rigidity for high-torque cutting scenarios. Choose based on maintenance needs: modular for frequent inspections, integral for heavy-duty emergency use. |
How to confirm if a replacement part is compatible with FZ28-35J/2FZ28-35J? | Cross-check the part number with the model’s dedicated parts lists: pipe rams use 2FZ2835DJ.02 series, shear rams use SR2870B/SBR2870SLA series, and seals use FZ2835DBJ/SKZF135 series. Ensure compliance with 35 MPa pressure rating and prioritize genuine parts to meet API Spec 16A. Avoid substituting parts from other FZ models (e.g., FZ28-70) due to dimension differences. |
Why does the secondary seal system fail to inject grease? | Common causes include clogged cocks (SFZ1310-30) or contaminated grease. Disassemble and clean the cock and external hexagonal blocking (SFZ1310-04), replace old grease with EM-09-1, and clear debris from the injection channel. Quarterly cleaning of the secondary seal system prevents this issue. |
What spare parts should be prioritized for one-year inventory? | Focus on high-wear components: SKZF135 Y-rings/backup rings, side door O-rings (437×7, 425×7), piston U-rings (SFZ1310-13), wear rings (FZ2835DBJ.02-09), and secondary sealing grease (EM-09-1). Stock 2-4 sets of these items, plus 1-2 shear blades (SR2870-06) for emergency replacement. |
Procurement Guidance
The performance and safety of FZ28-35J/2FZ28-35J BOPs depend on the quality and compatibility of replacement parts. We offer a full range of genuine parts for these models, including all ram types (pipe, shear, integral shear, variable diameter), seals, piston components, hinge structures, and secondary seal system parts—all manufactured to API Spec 16A and GB standards, ensuring perfect fit and pressure resistance. Our parts come with traceable production batch records and material certificates, confirming compliance with 35 MPa rating requirements and corrosion resistance for drilling fluid environments.
Whether you need routine spare parts, emergency repair components, or technical support for parts selection, our team of well control experts provides tailored solutions. We align with your operational schedule and maintenance needs to optimize inventory costs—for dual-ram 2FZ28-35J, we recommend doubling key seal and piston part quantities to match its dual-assembly design. For high-wear components like shear blades and ram seals, we offer competitive pricing for bulk orders without compromising quality. Contact us today to discuss your parts requirements and access professional guidance to ensure compliance with industry safety standards.
Conclusion
The FZ28-35J and 2FZ28-35J Ram BOPs are critical for medium-pressure oil and gas drilling, offering versatility, redundancy, and reliable well control through specialized ram configurations and robust sealing systems. Proper parts selection, proactive maintenance, and efficient troubleshooting are essential to maximizing equipment service life and ensuring operational safety. This guide provides comprehensive technical insights, practical maintenance recommendations, and real-world repair cases to support technicians and procurement professionals in daily operations.
By adhering to the compatibility guidelines, maintenance best practices, and procurement standards outlined herein, you can ensure your FZ28-35J/2FZ28-35J BOPs perform consistently under harsh drilling conditions. Partnering with a trusted supplier for genuine parts not only guarantees compliance with API and GB standards but also provides peace of mind for critical well control scenarios, minimizing downtime and safeguarding personnel and assets.
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