Introduction
This guide is exclusively tailored for Shanghai Shenkai’s FZ3535Ⅱ (single ram) and 2FZ3535Ⅱ (double ram) Ram Blowout Preventers (BOPs), specialized well control devices engineered for medium-pressure oil and gas drilling operations. It caters to the core needs of drilling contractors, on-site maintenance technicians, and procurement specialists in the oilfield industry, focusing on the models’ standard ram components, unique part ecosystem—including 2S85 series ordinary rams, SKZF/SKHF sealing assemblies, and 2S103 series structural parts—and practical application guidelines. Its core purpose is to serve as a dual-functional reference: providing precise part compatibility, procurement benchmarks, and inventory optimization strategies, while delivering actionable technical solutions for on-site fault diagnosis, repairs, and routine maintenance. Compliant with API Spec 16A (Wellhead and Christmas Tree Equipment) and Chinese national standards (GB/T 77, GB 1235), this guide ensures FZ3535Ⅱ/2FZ3535Ⅱ operations adhere to strict industry safety protocols, minimize unplanned downtime, and maximize operational efficiency. Whether for daily upkeep, emergency repairs, or bulk parts sourcing, the content integrates field-validated experience and authoritative technical insights to safeguard wellbore integrity and personnel safety in targeted drilling scenarios.
Product Overview
The Shanghai Shenkai FZ3535Ⅱ series BOPs (single and double ram configurations) are designed for reliable well control in medium-pressure drilling environments, with a focus on versatility and durability. The single ram model (FZ3535Ⅱ) and double ram variant (2FZ3535Ⅱ) share core structural and hydraulic components, differing primarily in the quantity of ram assemblies and associated parts—with the double ram model featuring twice the number of key components (e.g., 2 vs 4 ram assemblies, 1 vs 2 left/right side doors). A standout feature of this series is its 2S85.01 series ordinary ram system, which covers blind rams and a wide range of pipe sizes (2 7/8″, 3 1/2″, 4″, 4 1/2″, 5″, 6 5/8″, 7″, 9 5/8″), each equipped with a dedicated ram body, front rubber core, and shared top rubber core (2S85.01A.03.00) to ensure targeted sealing performance. Core components include piston rod seal assembly (DFZ5414/SKZF series), secondary sealing mechanism (SFZ2835 series, EM-09-1 grease), locking shaft seal assembly (2FZ1870DBYS/SFZ1310 series), and 2S103 series hinge structures—all engineered for interchangeability, corrosion resistance, and easy on-site maintenance under harsh drilling fluid conditions. The standardized part numbering system and high component commonality between the two models simplify inventory management and reduce procurement costs.
Functional Description
The FZ3535Ⅱ series BOPs deliver precise, reliable well control through coordinated operation of their specialized components, tailored to medium-pressure drilling requirements:
Multi-Size Ram Sealing Control: The 2S85.01 series ordinary rams provide comprehensive sealing solutions for diverse drilling scenarios. Blind rams (2S85.01A.00) enable full wellbore closure during maintenance or emergency shutdowns, while pipe rams (2S85.01B.00 to 2S85.01I.00) seal around corresponding drill pipe sizes to maintain pressure control during drilling operations. Each ram assembly includes one ram body, one size-specific front rubber core, and one shared top rubber core (2S85.01A.03.00), ensuring consistent sealing integrity across all ram types.
Layered Sealing Protection: The sealing system integrates multiple defensive layers to prevent leakage: piston rod seal assembly (SKZF100.01 Y-rings, GB1235 O-rings, DFZ5414 retainer rings) safeguards hydraulic fluid integrity at the piston rod; locking shaft seal set (2FZ1870DBYS lip seals, SFZ1310 dust seals) prevents contamination and leakage at the locking shaft; and the secondary sealing mechanism (SFZ2835 cocks/ plugs, EM-09-1 grease) allows on-site emergency leak remediation without disassembling the main structure. C663-22 series support rings enhance seal stability and prevent extrusion under pressure.
Hydraulic Actuation & Locking: Hydraulic cylinders (2S103.03.04) drive piston (2S103.03.05) and piston rod (2S103.03.02) movement to actuate rams, with SKHF250.01.00 bidirectional piston seals ensuring efficient hydraulic power transmission. Locking shafts (2S103.03.06) secure ram positions after actuation, while anti-loosening block (C17.08.03) and GB/T77 M12×20 screws prevent accidental loosening, enhancing operational safety.
Stable Hinge & Structural Support: The 2S103.05 hinge seat and associated components (GB/T118 locating pins, 2S103.07 screws) provide stable support for side doors, ensuring smooth opening/closing and precise alignment of ram assemblies. O-rings (31.5×3.55, 43.7×3.55) seal hinge and flange connections, preventing fluid intrusion and structural corrosion.
Structural Features
The FZ3535Ⅱ series BOPs feature a robust, maintenance-friendly design optimized for reliability, easy serviceability, and adaptability to on-site conditions:
Standardized Part Ecosystem with High Commonality: Core components follow a consistent naming convention, with 2S85 series for ram assemblies, 2S103 series for structural parts (housing, cylinders, hinge), and SKZF/SKHF/SFZ series for sealing and auxiliary components. High part commonality between single and double ram models reduces inventory complexity, while size-specific ram cores (front rubber cores) ensure compatibility with diverse pipe sizes.
Modular Sealing & Structural Design: Sealing assemblies adopt modular design, allowing technicians to replace worn seals without disassembling the entire hydraulic or locking system. Hinge-structured side doors enable quick access to ram assemblies, significantly reducing maintenance time and downtime during on-site repairs.
Corrosion & Contamination Resistance: Key components are engineered to withstand harsh drilling environments—SFZ1310 dust seals prevent solid particle contamination of locking shaft seals, while O-rings and support rings resist corrosion from drilling fluids. The housing (2S103.02) and structural parts are made of high-strength materials to ensure long-term durability under pressure and environmental stress.
User-Centric Safety & Operability: Standardized fasteners (GB5782 bolts, GB/T77 screws) enable technicians to use common tools for disassembly and reassembly. Redundant sealing layers and reliable locking mechanisms minimize leakage and accidental ram displacement risks, aligning with strict oilfield safety standards.
Applicable Operating Conditions
The FZ3535Ⅱ (single ram) and 2FZ3535Ⅱ (double ram) BOPs are optimized for medium-pressure onshore and shallow offshore drilling scenarios, with specific applicability to the following conditions:
Pressure & Fluid Compatibility: Designed for medium-pressure drilling operations, compatible with working pressures typical of onshore oil and gas wells. The sealing system is resistant to water-based mud (WBM), oil-based mud (OBM), and synthetic-based mud (SBM), ensuring stable performance in diverse fluid environments.
Pipe Size Adaptability: With support for 8 pipe sizes (2 7/8″ to 9 5/8″) and blind rams, the series is highly versatile for wells with complex casing programs and diverse drill pipe dimensions, widely used in onshore oilfields and shallow offshore platforms.
Well Types & Operations: Ideal for onshore drilling, workover operations, and shallow offshore drilling projects. The double ram model (2FZ3535Ⅱ) provides enhanced safety redundancy for high-risk wells with moderate formation pressure fluctuations, while the single ram model (FZ3535Ⅱ) offers cost-effective performance for standard drilling scenarios.
Environmental Resilience: Suitable for ambient temperatures common in most onshore and shallow offshore regions, with sealing components and structural parts designed to resist moisture, dust, and drilling fluid corrosion, ensuring consistent performance in harsh field conditions.
Maintenance & Care Recommendations
Proactive maintenance is critical to extending the service life and ensuring the reliability of FZ3535Ⅱ series BOPs. Below are model-specific best practices aligned with API Spec 16A and relevant standards:
Regular Inspection Schedules: Conduct weekly visual checks of sealing components, hydraulic connections, hinge structures, and locking shafts for leaks, corrosion, or wear. Perform quarterly disassembly inspections of ram assemblies, sealing groups, and secondary sealing mechanisms—replace worn parts per the recommended spare parts list. Verify the integrity of O-rings and support rings during each inspection to prevent extrusion under pressure.
Seal Maintenance: Replace SKZF100.01 Y-rings, 2FZ1870DBYS lip seals, and SFZ1310 dust seals every 6 months or if cracks/deformation are detected. Inject EM-09-1 secondary seal grease every 3 months to maintain leak resistance and lubricate sealing surfaces. Clean sealing grooves thoroughly before installing new seals to remove residue and ensure proper seating.
Ram & Actuation System Care: Clean ram bodies and rubber cores after each use to remove drilling fluid residue, avoiding damage to rubber surfaces. Verify ram alignment via hinge structures and locating pins (2FZ3535-16) during reassembly. Lubricate piston rods, locking shafts, and hinge components monthly with anti-corrosion lubricant to reduce friction and prevent seizing.
Fastener & Structural Maintenance: Torque side door bolts (2S103.06), hydraulic cylinder bolts (2S103.03.09), and hinge screws (2S103.07) to manufacturer specifications during each inspection. Check 止松块 (C17.08.03) for tightness and replace worn or deformed fasteners (GB5782, GB/T77) immediately to maintain structural integrity.
Auxiliary Component Care: Clean SFZ2835 cocks and plugs quarterly to prevent clogging from dried grease or debris. Inspect dust seals (SFZ1310-23) for damage and replace to prevent contamination of locking shaft seals. Verify the functionality of secondary sealing grease injection lines to ensure emergency usability.
Parts List for Common Gate Valves
Gate specification | Gate plate assembly | Gate plate body (1) | Front rubber core (1) | Top rubber core (1) |
Fully enclosed | 2S85.01A.00 | 2S85.01A.02 | 2S85.01A.01.00 | 2S85.01A.03.00 |
3 1/2" | 2S85.01B.00 | 2S85.01B.02.00 | 2S85.01B.01.00 | 2S85.01A.03.00 |
2 7/8" | 2S85.01C.00 | 2S85.01C.02.00 | 2S85.01C.01.00 | 2S85.01A.03.00 |
5" | 2S85.01D.00 | 2S85.01D.02.00 | 2S85.01D.01.00 | 2S85.01A.03.00 |
4" | 2S85.01E.00 | 2S85.01E.02.00 | 2S85.01E.01.00 | 2S85.01A.03.00 |
6 5/8" | 2S85.01F.00 | 2S85.01F.02.00 | 2S85.01F.01.00 | 2S85.01A.03.00 |
4 1/2" | 2S85.01G.00 | 2S85.01G.02.00 | 2S85.01G.01.00 | 2S85.01A.03.00 |
7" | 2S85.01H.00 | 2S85.01H.02.00 | 2S85.01H.01.00 | 2S85.01A.03.00 |
9 5/8" | 2S85.01I.00 | 2S85.01I.02.00 | 2S85.01I.01.00 | 2S85.01A.03.00 |
Parts List of Piston Rod Seal Assembly
Name | Part number/Model number |
retaining ring | DFZ5414-33A |
thrust bushing | 2S97.03.03 |
Gate plate shaft Y-type sealing ring | SKZF100.01 |
gasket | SKZF100.02 |
Packing support ring | 2S97.03.04 |
O-ring | GB1235 120×3.1 |
O-ring | GB1235 105×3.1 |
Parts List of Secondary Sealing Mechanism
Name | Part number/Model number |
NPT1″ pipe plug | SFZ2835-38 |
Secondary seal cock | SFZ2835-37 |
Secondary sealing grease | EM-09-1 |
Plug NPT1 (with hole) | SFZ2835-40 |
Parts List of Locking Shaft Seal Assembly
Name | Part number/Model number |
retainer ring | GB/T893.1 95 |
packing gland sleeve | SFZ1310-21 |
Lip-shaped seal ring cover | 2FZ1870DBYS.03-23 |
Lip seal ring | 2FZ1870DBYS.03.22-00 |
Dust seal seat | SFZ1310-22 |
dust seal | SFZ1310-23 |
Detailed List of Hinge Structures
Name | Part number/Model number |
hinge base | 2S103.05 |
locating pin | GB/T118 A16×60 |
Hinge seat screw | 2S103.07 |
screw | GB5782 M20×100 |
O-ring | 43.7×3.55 |
Support ring | C663-22 Ф44×Ф50×1.25 |
Name | Part number/Model number | |
shell | 2S103.02().00 | |
Ram assembly | 2S85.01().00 | |
Side door bolt | 2S103.06 | |
Hinge structure | 详见3.2.6 | |
O-ring | 31.5×3.55 | |
plug | 2C01.21 | |
bolt | GB5782 M16×50 | |
Nozzle flange | 2S84.10 | |
O-ring | 43.7×3.55 | |
Right liquid cylinder head | 2S103.03.08.00 | |
Left cylinder head | 2S103.04.02.00 | |
Locking shaft seal assembly | 详见3.2.4 | |
fluid cylinder | 2S103.03.04 | |
Hexagon socket head screw | GB/T77 M12×20 | |
anti-loosening block | C17.08.03 | |
piston | 2S103.03.05 | |
Two-way piston seal | SKHF250.01.00 | |
O-ring | 99.5×5.7 | |
Support ring | C663-22 Ф100×Ф110×1.9 | |
Right door | 2S103.03.01.00 | |
Left door | 2S103.04.01.00 | |
Secondary sealing mechanism | 详见3.2.3 | |
locating pin | 2FZ3535-16 | |
Piston rod seal assembly | 详见3.2.2 | |
piston rod | 2S103.03.02 | |
O-ring seal | 2S78.03.08 | |
support ring | C663-22 Ф32.52×Ф38×1.4 | |
YouTube | 2S103.03.03 | |
Locking shaft | 2S103.03.06 | |
O-ring seal | 240.67×5.33 | |
Support ring | C663-22 Ф241.4×Ф250×1.7 | |
NPT 1/2" plug | 2C01.36 | |
Liquid cylinder bolt | 2S103.03.09 | |
cap nut | 2S103.03.07 | |
Support ring | C663-22 Ф44×Ф50×1.25 | |
O-ring | 31.5×3.55 | |
O-ring | 43.7×3.55 | |
Lip-shaped seal ring cover | 2FZ1870DBYS.03-23 | |
Lip seal ring | 2FZ1870DBYS.03.22-00 | |
dust seal | SFZ1310-23 | |
Anti-loosening block | C17.08.03 | |
Bidirectional piston seal | SKHF250.01.00 | |
O-ring | 99.5×5.7 | |
Support ring | C663-22 Ф100×Ф110×1.9 | |
Secondary sealing grease | EM-09-1 | |
Gate plate shaft Y-type seal ring | SKZF100.01 | |
washer | SKZF100.02 | |
O-ring | GB1235 120×3.1 | |
O-ring | GB1235 105×3.1 | |
O-ring seal | 2S78.03.08 | |
Support ring | C663-22 Ф32.52×Ф38×1.4 | |
O-ring seal | 240.67×5.33 | |
Support ring | C663-22 Ф241.4×Ф250×1.7 |
Field Fault Repair Cases
The following real-world cases provide practical troubleshooting tips for common FZ3535Ⅱ series faults, helping technicians resolve issues quickly and minimize downtime:
Case 1: Piston Rod Hydraulic Leakage
Symptom: Hydraulic fluid leakage around the piston rod. Root Cause: SKZF100.01 Y-rings were degraded by high-temperature hydraulic fluid, and GB1235 120×3.1 O-rings were deformed, compromising sealing integrity. Repair: Replaced the entire piston rod seal set (Y-rings, O-rings, retainers, washers), cleaned the piston rod surface to remove burrs, and inspected the support sleeve (2S97.03.03) for damage. Post-repair hydraulic pressure testing confirmed no leakage. Preventive Measure: Replace the seal set every 6 months and monitor hydraulic fluid temperature to avoid exceeding operational limits.
Case 2: Ram Misalignment & Jamming
Symptom: 2S85.01D.00 5″ pipe ram jammed during actuation, with visible misalignment. Root Cause: Wear and deformation of hinge seat locating pins (GB/T118 A16×60) caused improper ram alignment, and drilling fluid residue buildup on guide surfaces exacerbated friction. Repair: Replaced worn locating pins, cleaned hinge components and ram guide surfaces with a compatible solvent, lubricated all moving parts, and realigned the ram assembly. The ram actuated smoothly post-repair. Preventive Measure: Inspect hinge pins monthly and clean guide surfaces weekly to remove residue.
Case 3: Secondary Sealing Grease Injection Failure
Symptom: Inability to inject EM-09-1 grease into the secondary sealing mechanism. Root Cause: SFZ2835-37 secondary sealing cocks were clogged with dried grease and debris, blocking grease flow. Repair: Disassembled the cocks and SFZ2835-40带孔螺塞, cleaned them thoroughly with a solvent, flushed the injection line, and reinstalled components. Grease flow was restored immediately.Preventive Measure: Clean secondary sealing components quarterly and flush the grease line during each maintenance cycle.
Case 4: Locking Shaft Leakage & Contamination
Symptom: Fluid leakage and dust contamination at the locking shaft. Root Cause: 2FZ1870DBYS.03.22-00 lip seals were worn, and SFZ1310-23 dust seals were damaged, allowing fluid leakage and particle intrusion. Repair: Replaced the entire locking shaft seal set (lip seals, dust seals, seal covers), cleaned the locking shaft to remove contamination, and inspected the seal groove for damage. Post-repair inspection confirmed no leakage or contamination. Preventive Measure: Replace dust seals every 3 months and lip seals every 6 months, and keep the locking shaft area clean during operation.
FAQ (Frequently Asked Questions)
Question | Answer |
Can top rubber cores be shared across different pipe ram sizes for FZ3535Ⅱ series? | Yes. All pipe ram sizes and blind rams share the same top rubber core (2S85.01A.03.00), enabling shared inventory. However, front rubber cores are size-specific (e.g., 2S85.01B.01.00 for 3 1/2″ rams), so always match the front core part number to the ram assembly to ensure proper sealing and pressure resistance. |
Are parts interchangeable between FZ3535Ⅱ (single) and 2FZ3535Ⅱ (double) models? | Most components are interchangeable, including ram assemblies, sealing groups (piston rod, locking shaft), secondary sealing parts, and hinge components. The only difference is quantity—double ram models require twice the number of core parts (e.g., 4 vs 2 ram assemblies, 2 vs 1 left/right side doors). Structural parts like the housing (2S103.02) are model-specific and not interchangeable. |
What is the role of C663-22 series support rings in the sealing system? | C663-22 support rings (e.g., Ф44×Ф50×1.25, Ф100×Ф110×1.9) prevent seal extrusion under pressure. They are installed alongside O-rings and lip seals to maintain seal shape and position, avoiding deformation or displacement during hydraulic actuation or pressure testing. Each support ring is sized for a specific seal and component, so always match the part number to the application location. |
How to maintain the functionality of hinge structures? | Lubricate hinge seats (2S103.05) and locating pins (GB/T118 A16×60) monthly with anti-corrosion lubricant to prevent seizing. Inspect hinge screws (2S103.07) for tightness during each maintenance cycle—loose screws cause misalignment. Replace worn or bent locating pins immediately, as misalignment can lead to ram jamming and seal damage. |
What precautions should be taken when replacing secondary sealing grease (EM-09-1)? | Ensure the grease is compatible with sealing materials (rubber, metal) to avoid degradation. Flush the injection line with clean solvent before refilling to remove dried residue. Inject grease slowly to prevent air entrapment, which can block flow during emergency use. Store EM-09-1 in a sealed container to avoid contamination, and replace expired grease promptly. |
Procurement Guidance
The safety and reliability of Shanghai Shenkai FZ3535Ⅱ/2FZ3535Ⅱ BOPs depend entirely on genuine, model-compatible parts. We supply a full range of authentic components tailored to these models, including 2S85.01 series ram assemblies (all sizes), piston rod/locking shaft sealing groups, secondary sealing mechanism parts, 2S103 series structural components, C663-22 support rings, and EM-09-1 grease. All parts are manufactured to API Spec 16A, GB standards, and Shanghai Shenkai’s original equipment specifications, with traceable material certificates and batch records to ensure perfect fit, pressure resistance, and consistent performance.
For procurement, prioritize high-wear components (SKZF100.01 Y-rings, 2FZ1870DBYS lip seals, SFZ1310 dust seals, C663-22 support rings) and size-specific ram parts (front rubber cores) based on your operational pipe sizes. Double quantities for 2FZ3535Ⅱ (double ram) models, and align with the recommended spare parts list to balance inventory cost and emergency response. Our oilfield technical experts provide free support to verify part compatibility, avoid mismatches, and optimize inventory based on your drilling scope. Whether you need routine spares, emergency repair parts, or bulk orders for fleet maintenance, we deliver consistent quality that meets industry safety standards. Contact us today to discuss your specific Shanghai Shenkai FZ3535Ⅱ series requirements and secure reliable parts for your well control operations.
Conclusion
The Shanghai Shenkai FZ3535Ⅱ (single ram) and 2FZ3535Ⅱ (double ram) BOPs are robust, versatile well control devices engineered to excel in medium-pressure onshore and shallow offshore drilling operations. Their wide pipe size compatibility (2 7/8″ to 9 5/8″), layered sealing protection, modular design, and high part commonality make them adaptable to diverse operational scenarios, from standard drilling to high-risk well interventions. The models’ maintenance-friendly structure and compliance with global industry standards ensure safe, consistent performance while minimizing downtime and procurement costs.
This guide integrates authoritative technical insights, field-proven repair cases, and procurement best practices to support technicians and procurement professionals in maintaining operational continuity. By following model-specific maintenance schedules, using genuine Shanghai Shenkai parts, and leveraging the FAQs and troubleshooting tips, you can maximize the FZ3535Ⅱ series’ service life and mitigate operational risks. Partnering with a trusted supplier for authentic components ensures compliance with safety protocols, safeguarding personnel, assets, and wellbore integrity. Invest in quality parts and proactive maintenance to keep your Shanghai Shenkai FZ3535Ⅱ BOPs operating at peak performance.
contact us ：
Emeil: [email protected] whatsapp: +86 15275658619
Should you have any purchase intentions, please contact us – we will offer you our most favorable price.