FZ35-35U Ram Blowout Preventer (BOP)

Introduction

This guide is exclusively tailored for the FZ35-35U Ram Blowout Preventer (BOP), including its single-ram (C26.100) and double-ram (2C26.100) configurations. It addresses the specialized needs of drilling contractors, on-site maintenance technicians, and procurement specialists in oil and gas well control operations, focusing on the model’s unique part ecosystem (e.g., 2C02 series pipe rams, SBR3570CC shear rams, and tandem booster hydraulic cylinders). Its core purpose is to serve as a dual-functional reference: providing precise part compatibility and procurement benchmarks for inventory planning, while delivering actionable technical solutions for on-site fault diagnosis, repairs, and maintenance. Compliant with API Spec 16A (Wellhead and Christmas Tree Equipment) and Chinese national standards (GB/T70.1-2000, UNC thread specifications), this guide ensures FZ35-35U operations adhere to industry safety protocols, minimize unplanned downtime, and optimize spare parts management. Whether for routine upkeep, emergency repairs, or bulk parts sourcing, the content integrates field-validated experience and authoritative technical insights to support the stable operation of this 35 MPa (5,075 psi) rated well control device—critical for safeguarding wellbore integrity and personnel safety.

Product Overview

The FZ35-35U is a medium-pressure Ram BOP engineered for 35 MPa working pressure, designed to meet the demands of onshore and shallow offshore drilling projects. Available in single-ram (C26.100) and double-ram (2C26.100) variants, it offers flexible well control solutions: the single-ram model provides cost-efficient performance for standard drilling scenarios, while the double-ram configuration delivers enhanced safety redundancy for high-risk wells with unstable formation pressure. A key distinguishing feature of the FZ35-35U is its comprehensive ram system, including 2C02 series pipe rams (covering 21 pipe sizes from 2 3/8” to 11 3/4” plus blind rams), SBR3570CC shear rams for emergency pipe cutting, and VBR3570CA/CB variable bore rams for multi-size adaptability. The model also supports both standard hydraulic cylinder assemblies and tandem booster hydraulic cylinders (2C26 series parts), enabling customized actuation performance for diverse operational needs. Core components—such as floating seal assemblies (2C12.08.00), SKZF101 series seals, and C17/C21 series hydraulic parts—are engineered for interchangeability, durability, and easy maintenance under medium-pressure, corrosive drilling conditions.

Functional Description

The FZ35-35U delivers reliable well control functions through coordinated operation of its specialized components, tailored to 35 MPa medium-pressure working conditions:

Multi-Type Ram Control: Pipe rams (2C02.01 series) cover an extensive range of pipe sizes and blind closure, with dedicated ram bodies, top seals, and front seals (noting that front seals for most pipe rams share the 2C02.01A.03 part number). Shear rams (SBR3570CC.00) enable emergency pipe cutting and sealing, with distinct left/right/top/front seals (e.g., SBR3570CB.03.00, SBR3570CB.02.00) for post-shear integrity. Variable bore rams (2 7/8”-5” and 4 1/2”-7”) adapt to multiple pipe sizes, reducing the need for separate ram assemblies.

Layered Sealing Protection: Floating seal assemblies (2C12.08.00) with O-rings (340×7, 360×5.3) form the primary barrier against wellbore fluid leakage at the bonnet. Operating piston rod seals—including SKZF101.01 Y-rings, U-seals (Φ76.2×92.08×14.27/15.72), and backup rings—prevent hydraulic fluid loss. The secondary sealing system (SFZ1310-30 plug cocks, SFZ1310-32.00 check valves) allows on-site injection of EM-09-01 grease without disassembling the BOP, enabling quick leak remediation.

Hydraulic Actuation & Tandem Boost Capability: Standard hydraulic cylinders (C17.06 series) drive ram movement via pressure, with piston assemblies (C21.08.00) ensuring smooth actuation. Tandem booster hydraulic cylinders (2C26 series) enhance actuation force for heavy-duty scenarios, integrating additional components like 2C26.06 cylinders, 2C26.11 oil blocks, and lip seals (2C01.08) for reliable performance. Both configurations use locking screws (C17.01) to secure ram positions under pressure.

Precision Guidance & Alignment: Ram guide pins (2C02.15) and guide rings (2C02.29) ensure accurate ram movement and alignment, preventing jamming and extending component service life. Operating piston assemblies include dedicated hooks (2C02.11A-02 for pipe rams, 2C02.11A-03 for shear rams) to ensure secure ram engagement.

Structural Features

The FZ35-35U features a modular, maintenance-friendly design with structural characteristics optimized for medium-pressure well control and adaptability:

Standardized & Model-Specific Part Ecosystem: The 2C02 series pipe rams use a consistent naming convention (2C02.01X.00 for assemblies, 2C02.01X.01 for bodies) across all sizes, simplifying part identification. Shared components—such as 2C02.01A.03 front seals for most pipe rams and SKZF101.01 Y-rings—reduce inventory complexity, while tandem booster parts (2C26 series) are fully compatible with the base model for easy upgrade.

Robust Seal Integration: Floating seal assemblies combine O-rings and a floating seal skeleton (2C12.08.01) to accommodate minor misalignments and prevent leakage. Hydraulic seals (U-seals, Y-rings, backup rings) are sized for 35 MPa pressure, with backup rings (e.g., Φ70×Φ80×1.9, Φ340×Φ355×2.75) preventing seal extrusion under high pressure.

Interchangeable Hydraulic Configurations: The model supports both standard and tandem booster hydraulic cylinders, with shared parts (e.g., SFZ1310-30 plug cocks, C17.01 locking screws) ensuring compatibility. This flexibility allows operators to adjust actuation performance based on well conditions without replacing the entire BOP.

User-Centric Maintenance Access: Key wear components—seals, backup rings, guide rings—are strategically positioned for easy access. Operating piston assemblies (C21.08.00) feature modular design, allowing technicians to replace individual parts (hooks, stop blocks, O-rings) without full disassembly, reducing maintenance time.

Applicable Operating Conditions

The FZ35-35U (single/double ram, standard/tandem booster) is optimized for 35 MPa medium-pressure drilling scenarios, with specific applicability to the following conditions:

Pressure & Temperature Range: Rated for 35 MPa working pressure and ambient temperatures from -20°C to 120°C (-4°F to 248°F), compatible with water-based mud (WBM), oil-based mud (OBM), and synthetic-based mud (SBM) commonly used in onshore and shallow offshore drilling.

Pipe Size Adaptability: Accommodates pipe sizes from 2 3/8” to 11 3/4” via 2C02 series pipe rams, plus blind rams for full wellbore closure. Variable bore rams cover size ranges (2 7/8”-5”, 4 1/2”-7”) to support wells with multiple casing programs and varying drill pipe diameters.

Well Types & Operations: Ideal for onshore oil and gas wells, shallow offshore wells (platform and jack-up rigs), and well completion stages. The shear ram assembly enables emergency pipe cutting for blowout prevention, making it suitable for wells with moderate formation pressure instability. Tandem booster configurations are recommended for heavy-duty applications or wells requiring enhanced actuation force.

Environmental Resilience: Seals and metal components (e.g., stainless steel retainer rings, 2C26 series cylinders) resist corrosion from drilling fluids, saltwater (offshore), and harsh atmospheric conditions, ensuring reliable performance in diverse operational environments.

Maintenance & Care Recommendations

Proactive maintenance is essential to extend the service life and ensure the reliability of FZ35-35U BOPs. Below are practical, model-specific best practices aligned with API Spec 16A and GB standards:

Regular Inspection Schedules: Conduct weekly visual checks of floating seal assemblies, hydraulic connections, and ram shafts for leaks, corrosion, or wear. Perform quarterly disassembly inspections of piston assemblies, ram seals, and guide rings—replace worn parts according to the one-year recommended spare parts list.

Seal Maintenance: Replace floating seal O-rings (340×7, 360×5.3) every 6 months or if cracks, deformation, or leakage is detected. Inspect SKZF101.01 Y-rings and U-seals (Φ76.2×92.08×14.27/15.72) monthly; replace them every 80 operational cycles or 6 months, whichever comes first. Inject EM-09-01 secondary sealing grease every 3 months to maintain the secondary seal system’s functionality.

Ram & Hydraulic System Care: Clean pipe, shear, and variable bore ram components after each use to remove drilling fluid residue. Verify that ram assembly part numbers match the pipe size (e.g., 2C02.01B.00 for 2 3/8” pipes) before installation. For tandem booster configurations, inspect 2C26.06 cylinders and 2C02.11A hooks quarterly to ensure secure engagement.

Piston & Actuation Maintenance: Inspect piston wear rings (2C01.48, 2C01.03.11) and lip seals (2C01.08) monthly for damage. Replace hydraulic cylinder O-rings (69.6×5.7, 78.74×5.33) if leaks occur, and torque bonnet bolts (C21.09) and hydraulic cylinder bolts (C17.05) to specified values after disassembly.

Guide & Alignment Care: Lubricate ram guide pins (2C02.15) and guide rings (2C02.29) monthly with anti-corrosion lubricant. Check backup rings (e.g., Φ102.31×Φ111.61×1.52) for deformation during quarterly inspections—replace to prevent seal failure.

Pipe Ram Parts Table

Shear Ram Assembly Parts Table

Variable Bore Ram Assembly Parts Table

Sealing Parts List of Operating Piston Front Rod

Secondary Sealing Mechanism Parts Table

Sealing Parts Table of Operating Piston Tail Rod

Bonnet Seal (Door Seal Ring) Assembly Parts List

BOP Parts List

Hydraulic Cylinder Assembly Parts List

Parts List for Hydraulic Cylinder Assembly with Tandem Booster

One-year recommended spare parts list

Field Fault Repair Cases

The following real-world cases provide practical troubleshooting tips for common faults in FZ35-35U BOPs, helping technicians resolve issues quickly and reduce downtime:

Case 1: FZ35-35U Floating Seal Leakage

Symptom: Wellbore fluid leakage at the bonnet during 35 MPa pressure testing. Root Cause: O-rings (340×7) in the floating seal assembly (2C12.08.00) were worn and contaminated with dried drilling mud, compromising the sealing surface. Repair: Replaced the 340×7 and 360×5.3 O-rings, cleaned the floating seal skeleton (2C12.08.01) with a non-abrasive tool, and reinstalled the assembly with calibrated torque. A follow-up pressure test confirmed no leakage. Preventive Measure: Clean the floating seal area after each well operation and inspect O-rings bi-weekly.

Case 2: FZ35-35U Ram Shaft Hydraulic Leakage

Symptom: Hydraulic fluid leakage around the operating piston front rod. Root Cause: SKZF101.01 Y-rings were degraded by high-temperature hydraulic fluid, and backup rings (Φ105.4×Φ114×1.7) were deformed. Repair: Replaced the Y-rings and backup rings, cleaned the piston rod to remove burrs, and inspected the supporting gland cover (C17.14) for damage. Post-repair actuation was smooth with no leakage.Preventive Measure: Replace SKZF101 series seals every 6 months, and monitor hydraulic fluid temperature to avoid premature degradation.

Case 3: 2C26.100 Double-Ram BOP Ram Jamming

Symptom: 2C02.01D.00 pipe ram (3 1/2”) jammed during actuation. Root Cause: Drilling fluid residue buildup on ram guide pins (2C02.15) and guide rings (2C02.29), combined with misalignment from loose socket head cap screws (GB/T77 M12×20). Repair: Disassembled the ram assembly, cleaned the guide pins and rings with a solvent, tightened the screws to specification, and lubricated the components. The ram actuated smoothly after reassembly. Preventive Measure: Clean guide pins and rings weekly, and check screw tightness during routine inspections.

Case 4: FZ35-35U Tandem Booster Hydraulic Failure

Symptom: Tandem booster hydraulic cylinder failed to provide enhanced actuation force. Root Cause: The 2C26.11 oil block was clogged with debris, and the lip seal (2C01.08) in the tandem piston was worn. Repair: Disassembled the oil block, cleaned it thoroughly with a compatible solvent, replaced the lip seal, and flushed the hydraulic line. Actuation force was restored to specifications. Preventive Measure: Clean the oil block and filter (muffler) quarterly, and inspect tandem-specific seals every 4 months.

FAQ (Frequently Asked Questions)

Procurement Guidance

The safety and reliability of FZ35-35U BOPs (single/double ram, standard/tandem booster) depend entirely on genuine, model-compatible parts. We supply a full range of authentic components tailored to this model, including 2C02 series pipe rams (all sizes), SBR3570CC shear rams, VBR3570CA/CB variable bore rams, floating seal assemblies (2C12.08.00), SKZF101 series seals, C17/C21 standard hydraulic parts, and 2C26 series tandem booster components. All parts are manufactured to API Spec 16A and GB standards, with traceable material certificates and batch records to ensure 35 MPa pressure resistance and perfect fit with original equipment.

For procurement, we recommend following the one-year recommended spare parts list to balance inventory cost and emergency response capability. For double-ram (2C26.100) models, double the quantity of key wear components (O-rings, seals, backup rings) to account for dual ram systems. For tandem booster configurations, prioritize tandem-specific parts (lip seals, oil blocks, cylinder components) alongside shared parts. Our team of well control experts provides free technical support for parts selection, helping you avoid compatibility issues (e.g., hook type, seal specificity) and optimize inventory. 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 FZ35-35U requirements and secure reliable parts for your well control operations.

Conclusion

The FZ35-35U Ram BOP (single/double ram, standard/tandem booster) is a versatile, medium-pressure well control device engineered for reliability and adaptability in oil and gas drilling. Its unique part ecosystem—including 2C02 series pipe rams, SBR3570CC shear rams, and tandem booster capability—makes it suitable for diverse operational scenarios, from standard onshore wells to high-risk projects requiring enhanced actuation force.

This guide integrates authoritative technical insights, field-proven repair cases, and procurement best practices to support technicians and procurement professionals in maintaining operational continuity and safety. By following model-specific maintenance schedules, using genuine compatible parts, and leveraging the FAQs and repair cases herein, you can maximize the service life of your FZ35-35U BOP and minimize downtime. Partnering with a trusted supplier for authentic parts ensures compliance with API and GB standards, safeguarding personnel, assets, and wellbore integrity in medium-pressure drilling environments. Invest in quality parts and proactive maintenance to keep your FZ35-35U operating at peak performance.

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