Shanghai Shenkai FZ2870SL/FZ3521SL/FZ3535SL/FZ3570SL SL Ram BOP

Introduction

This guide is exclusively tailored for Shanghai Shenkai’s SL series Ram Blowout Preventers (BOPs), including FZ2870SL, FZ3521SL, FZ3535SL, and FZ3570SL models—specialized well control devices engineered for medium-pressure oil and gas drilling operations. It caters to the refined needs of drilling contractors, on-site maintenance technicians, and procurement specialists in the oilfield industry, focusing on the series’ pipe ram assemblies, model-specific sealing systems, hinge structures, and dedicated part ecosystems (2FZ3535TFI, 2FZ3570ASL, SKZF series components). Its core purpose is to serve as a dual-functional reference: providing precise part compatibility across models, procurement benchmarks, and model-specific one-year spare parts inventory 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, GB 118), this guide ensures consistent, safe operation of SL series BOPs, minimizes unplanned downtime, and optimizes operational efficiency. Whether for daily upkeep, emergency leak remediation, or bulk parts sourcing, the content integrates field-validated experience and authoritative technical insights to safeguard wellbore integrity and personnel safety in complex drilling scenarios.

Product Overview

The Shanghai Shenkai SL series BOPs (single ram configurations) are designed to deliver reliable well control with model-specific adaptability, covering diverse pipe size ranges and operational demands. FZ3521SL and FZ3535SL share a unified pipe ram system (2FZ3535TFI series), supporting 10 pipe sizes (2 3/8″ to 9 5/8″) and blind closure, each equipped with ram assemblies, blocks, retaining/retracting screws, holders, and size-specific rubber seals—with standardized fasteners (2FZ3535TFI.02A.03/.04/.05) across all sizes to simplify inventory. FZ3570SL adopts the 2FZ3570ASL pipe ram series, compatible with 8 pipe sizes (2 7/8″ to 9 5/8″) and blind closure, featuring model-exclusive hinge brackets and ram components. FZ2870SL is optimized for medium-pressure scenarios, with a dedicated 2FZ2870ASL part ecosystem and pipe ram compatibility tailored to common drilling specifications. All models share core structural modules: side door seal structures, ram shaft seal assemblies (SKZF series Y-rings/backup rings), secondary seal systems (EM-09-1 grease, SFZ series cocks/plugs), and locking shaft seal assemblies (2FZ3570ASL lip rings/wiper rings), while differing in part numbers and quantities to match model-specific dimensions. The series leverages standardized hydraulic actuation components (pistons, cylinders, seals) and hinge structures, ensuring operational consistency across models while accommodating unique size and pressure requirements.

Functional Description

The SL series BOPs deliver comprehensive well control through coordinated operation of pipe ram assemblies, sealing systems, and hydraulic actuation modules, tailored to medium-pressure drilling requirements:

Model-Specific Pipe Ram Sealing: FZ3521SL/FZ3535SL use 2FZ3535TFI pipe rams to seal 2 3/8″–9 5/8″ pipes and blind closures, with size-specific rubber seals (2FZ3535TFI.02B–M.01.00) ensuring tight contact with drill pipes. FZ3570SL employs 2FZ3570ASL pipe rams for 2 7/8″–9 5/8″ pipes, with dedicated ram blocks and seals to match its structural dimensions. Each ram assembly is secured by retaining screws and positioned via holders, enabling smooth actuation and reliable sealing under operating pressure.

Layered Sealing Protection: A multi-stage sealing system ensures leak resistance: side door seals (model-specific part numbers: 2FZ3535ASL.03.03-00 for FZ3521SL/FZ3535SL, 2FZ3570ASL.06-00 for FZ3570SL) prevent fluid intrusion at door connections; ram shaft seal assemblies (SKZF107.01/133.01 Y-rings, SKZF107.02/133.02 backup rings) safeguard hydraulic fluid integrity, with model-specific part matches (SKZF107 for FZ3521SL/FZ3535SL, SKZF133 for FZ2870SL/FZ3570SL); locking shaft seal assemblies (2FZ3570ASL lip rings/wiper rings) prevent contamination; and secondary seal systems allow on-site injection of EM-09-1 grease via SFZ series cocks for emergency leak remediation without disassembly. Backup rings (C663-22, 2FZ3570ASL-18) enhance seal stability and prevent extrusion under pressure.

Hydraulic Actuation & Locking: Hydraulic cylinders (model-specific: 2FZ3535ASL.03-05 for FZ3521SL/FZ3535SL, 2FZ3570ASL-09 for FZ3570SL) drive piston and ram shaft movement, with dedicated piston seals (2FZ3535ASL.03.09-00, 2FZ3570ASL.12-00) ensuring efficient power transmission. Locking screws and nuts secure ram positions after actuation, preventing accidental displacement, while wear rings reduce friction between moving parts, extending component service life. Locating pins align rams and hinge structures, ensuring precise actuation and sealing.

Stable Hinge & Structural Support: Hinge structures are model-exclusive: FZ3521SL/FZ3535SL use 2FZ3535ASL-05 hinge blocks and GB118-86 A16×80 locating pins; FZ2870SL adopts 2FZ2870ASL-04 hinge blocks and larger A20×80 pins; FZ3570SL features dedicated right/left hinge brackets (2FZ3570ASL-25/-03) and hinge pins. O-rings (43.7×3.55, 47.5×5.3) seal hinge connections, preventing fluid intrusion and corrosion, while oil cups (where applicable) ensure lubrication for smooth side door operation.

Structural Features

The SL series BOPs feature a robust, maintenance-friendly design with model-specific adaptations and shared core advantages:

Model-Specific Compatibility with Shared Standards: Each model is optimized for specific pipe size ranges and structural dimensions, but all adhere to unified API Spec 16A standards. Shared components (locking shaft seals, secondary seal grease, cap nuts) reduce inventory complexity, while model-exclusive parts (ram assemblies, hinge blocks, side door seals) ensure precise fit and performance.

Modular Sealing & Accessible Design: Sealing assemblies (ram shaft, locking shaft) adopt modular design, allowing technicians to replace worn parts without full disassembly. Hinge-structured side doors enable quick access to ram assemblies, significantly reducing maintenance time. Standardized fasteners (GB70, GB5782) allow the use of common tools for on-site repairs across all models.

Pressure & Corrosion Resistance: Structural parts (bodies, cylinders, hinge blocks) are made of high-strength materials to withstand medium-pressure operations. Sealing components (SKZF rings, rubber seals) resist corrosion from water-based/oil-based/synthetic-based drilling fluids, with model-specific material selections to match operational demands. Wiper rings and dust seals prevent solid particle contamination, extending component service life.

Optimized Spare Parts Ecosystem: Each model has a tailored one-year spare parts list, prioritizing high-wear components (seals, O-rings, wear rings) to minimize downtime. The shared use of key components (EM-09-1 grease, 2FZ3570ASL lip rings) across models simplifies cross-model inventory management for fleets operating multiple SL series BOPs.

Applicable Operating Conditions

The SL series BOPs (FZ2870SL/FZ3521SL/FZ3535SL/FZ3570SL) are optimized for medium-pressure onshore and shallow offshore drilling scenarios, with model-specific adaptability:

Pressure & Fluid Compatibility: All models are rated for medium-pressure drilling operations, with sealing systems compatible with water-based mud (WBM), oil-based mud (OBM), and synthetic-based mud (SBM). Model-specific seal designs (e.g., SKZF133 for FZ2870SL/FZ3570SL) ensure stability under varying pressure and fluid conditions.

Pipe Size Adaptability: FZ3521SL/FZ3535SL cover the widest range (2 3/8″–9 5/8″), ideal for wells with diverse casing programs. FZ3570SL (2 7/8″–9 5/8″) and FZ2870SL (tailored to common sizes) suit specialized drilling needs, reducing the need for multiple BOP units across projects.

Well Types & Operations: Suitable for onshore drilling, workover operations, and shallow offshore platforms, particularly in regions with moderate formation pressure fluctuations. The series’ reliability and easy maintenance make it ideal for both long-term drilling projects and temporary well control applications.

Environmental Resilience: Designed to withstand ambient temperatures common in most onshore and shallow offshore regions (-20℃ to 60℃). Components resist moisture, dust, and drilling fluid corrosion, ensuring consistent performance in harsh field conditions with minimal maintenance.

Maintenance & Care Recommendations

Proactive, model-specific maintenance is critical to extending the service life of SL series BOPs. Below are best practices aligned with API Spec 16A and manufacturer guidelines:

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 seal systems—replace worn parts per the model-specific one-year spare parts list. Verify O-ring and backup ring integrity, ensuring no extrusion or deformation under pressure.

Seal Maintenance: Replace model-specific Y-rings (SKZF107.01 for FZ3521SL/FZ3535SL, SKZF133.01 for others), lip rings (2FZ3570ASL.16.03-00), and wiper rings every 6 months or if damage is detected. Inject EM-09-1 grease every 3 months into the secondary seal system, flushing lines first to remove dried residue. Clean sealing grooves thoroughly before installing new seals to ensure proper seating.

Ram & Actuation System Care: Clean ram bodies and rubber seals after each use to remove drilling fluid residue, avoiding damage to rubber surfaces. Inspect ram alignment via locating pins and hinge structures during reassembly. Lubricate piston rods, locking shafts, and hinge components monthly with anti-corrosion lubricant—use oil cups (where fitted) to ensure consistent lubrication.

Fastener & Structural Maintenance: Torque door bolts, hydraulic cylinder bolts, and hinge screws to model-specific specifications (e.g., M20×90 for FZ3521SL/FZ3535SL, M24×125 for FZ2870SL) during each inspection. Check locking nuts and stop blocks for tightness, replacing worn or deformed fasteners immediately. Inspect hinge pins and blocks for smooth rotation, replacing if noisy or seized.

Auxiliary Component Care: Clean SFZ series cocks, plugs, and check valves quarterly to prevent clogging. Flush secondary seal grease injection lines to ensure emergency usability. For FZ3570SL, inspect hinge brackets and pins regularly, replacing O-rings (47.5×5.3) if leakage occurs. Store EM-09-1 grease in a sealed container to avoid contamination.

Parts of pipe ram of FZ3521SL/FZ3535SL

Parts of pipe ram of FZ3570SL

Part list of Side Door Seal Structure

Part list of Ram Shaft Seal Assembly of FZ2870SL

Part list of Ram Shaft Seal Assembly of FZ3521SL/FZ3535SL

Part list of Ram Shaft Seal Assembly of FZ3570SL

Parts list of Secondary Seal System

Parts list of Locking Shaft Seal Assembly

Parts list of Hinge structure

Parts list of Hinge structure of 3570SL

Parts List of FZ2870SL

Parts List of FZ3521SL/FZ3535SL

Parts List of FZ3570SL

FZ2870SL Spare Parts list for one year

FZ3521SL/FZ3535SL Spare Parts list

FZ3570SL Spare Parts list for one year

Field Fault Repair Cases

The following real-world cases provide model-specific troubleshooting tips for common SL series faults, helping technicians resolve issues quickly:

Case 1: Ram Shaft Leakage (FZ3521SL/FZ3535SL)

Symptom: Hydraulic fluid leakage around the ram shaft. Root Cause: SKZF107.01 Y-rings were degraded by high-temperature fluid, and SKZF107.02 backup rings were deformed, compromising sealing. Repair: Replaced the entire ram shaft seal set (Y-rings, backup rings, wiper rings), cleaned the ram shaft to remove burrs, and inspected the packing bearing ring (2FZ3535ASL.03.01-05). Post-repair pressure testing confirmed no leakage. Preventive Measure: Replace SKZF107 series seals every 6 months and monitor hydraulic fluid temperature.

Case 2: Side Door Leakage (FZ3570SL)

Symptom: Fluid leakage at the side door connection. Root Cause: Side door seal (2FZ3570ASL.06-00) was worn, and hinge bracket O-rings (2FZ3570ASL-24) were aged. Repair: Replaced the side door seal and hinge O-rings, cleaned the sealing surface, and torqued door bolts (SFZ1310-33) to specifications. Leakage was eliminated. Preventive Measure: Replace side door seals and hinge O-rings every 6 months, checking bolt torque weekly.

Case 3: Secondary Seal Grease Injection Failure (FZ2870SL)

Symptom: Inability to inject EM-09-1 grease into the secondary seal system. Root Cause: SFZ1310-30 cocks were clogged with dried grease, and SFZ1310.32-00 check valves were stuck. Repair: Disassembled cocks and check valves, cleaned with solvent, flushed the injection line, and reinstalled. Grease flow was restored. Preventive Measure: Clean secondary seal components quarterly and flush lines during maintenance.

Case 4: Ram Misalignment & Jamming (FZ3535SL)

Symptom: 4 1/2″ pipe ram jammed during actuation, with visible misalignment. Root Cause: Locating pins (GB118-86 A16×80) were worn, causing ram displacement, and drilling fluid residue built up on ram guides.Repair: Replaced worn locating pins, cleaned ram bodies and guides, lubricated hinge components, and realigned the ram assembly. Smooth actuation was restored. Preventive Measure: Inspect locating pins monthly and clean ram guides after each use.

FAQ (Frequently Asked Questions)

Procurement Guidance

The safety and reliability of Shanghai Shenkai SL series BOPs depend on genuine, model-compatible parts. We supply a full range of authentic components tailored to each model, including 2FZ3535TFI/2FZ3570ASL pipe ram assemblies (all sizes), ram shaft/locking shaft sealing groups, side door seals, secondary seal system parts, hinge components, and model-specific one-year spare parts lists. All parts comply with API Spec 16A, GB standards, and Shanghai Shenkai’s original specifications, with traceable material certificates and batch records to ensure perfect fit, pressure resistance, and consistent performance.

For procurement, prioritize high-wear components from each model’s one-year spare parts list (e.g., SKZF series seals, O-rings, wear rings). Stock size-specific rubber seals for commonly used pipe diameters in your operations, and leverage shared components to reduce inventory costs. Our oilfield technical experts provide free support to verify part compatibility, avoid mismatches, and optimize inventory based on your fleet’s model mix and operational frequency. 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 SL series requirements and secure reliable parts for your well control operations.

Conclusion

The Shanghai Shenkai FZ2870SL/FZ3521SL/FZ3535SL/FZ3570SL SL series BOPs are versatile, reliable well control devices engineered to excel in medium-pressure onshore and shallow offshore drilling operations. Their model-specific pipe size adaptability, layered sealing protection, modular design, and shared component ecosystem balance specialized performance with operational efficiency. FZ3521SL/FZ3535SL offer the widest pipe size range, FZ3570SL delivers tailored performance for specific applications, and FZ2870SL provides cost-effective medium-pressure solutions—all adhering to strict global safety standards.

This guide integrates authoritative technical insights, model-specific repair cases, and procurement best practices to support technicians and procurement professionals. By following model-specific maintenance schedules, using genuine parts, and leveraging the FAQs, you can maximize the SL 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 SL series BOPs operating at peak performance.

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