FZ35-35U & 2FZ35-35U Ram-Type Blowout Preventer

1. Product Introduction

The FZ35-35U (single ram) and 2FZ35-35U (double ram) Ram-Type Blowout Preventers (BOPs) are critical well control devices engineered for oil and gas drilling operations, designed to mitigate blowout risks by sealing the wellbore during drilling, completion, and workover activities. Manufactured in strict compliance with API Spec 16A (Specification for Wellhead and Christmas Tree Equipment) and GB/T 22513 standards, these BOPs feature a 13 5/8-inch (346.1mm) bore and 35MPa (5000psi) rated working pressure, making them ideal for medium-pressure drilling scenarios.

Crafted with high-strength alloy steel bodies and precision-engineered sealing components, the FZ35-35U series delivers reliable pressure containment and rapid response to wellbore pressure surges. The product line supports multiple ram configurations—including pipe rams, shear rams, and variable bore rams (VBR)—to accommodate diverse downhole tools and pipe sizes, from 2 3/8-inch to 11 3/4-inch drill pipes and casings. All critical components, such as the hydraulic cylinder assembly, secondary sealing mechanism, and bonnet seals, undergo rigorous non-destructive testing (NDT) including ultrasonic and magnetic particle inspections to ensure compliance with HSE and industry reliability requirements.

2. Core Purpose

The primary purpose of the FZ35-35U and 2FZ35-35U BOPs is to provide fail-safe wellbore isolation for onshore and shallow offshore drilling operations, addressing the subdivided needs (segmented needs) of E&P (Exploration and Production) companies, drilling contractors, and well service providers. Specifically, these BOPs are designed to: seal the annular space around drill pipes/casings (pipe rams), cut through drill pipe to isolate the wellbore in emergency scenarios (shear rams), and adapt to multiple pipe sizes without ram replacement (variable bore rams).

They serve as a core component of the well control system, working in tandem with choke manifolds, kill lines, and hydraulic control units to maintain wellbore integrity, prevent formation fluid influx (kick), and mitigate blowout hazards. The double ram model (2FZ35-35U) offers enhanced redundancy for high-risk operations, while the single ram model (FZ35-35U) provides a cost-effective solution for standard drilling environments—both tailored to minimize downtime and ensure operational safety.

3. Functional Description

3.1 Ram Operation

The BOPs utilize hydraulic actuation with a rated control pressure of 21MPa (3000psi) and a recommended operating pressure range of 8.4-10.5MPa (1200-1500psi) for optimal performance. The closing ratio is 11.6:1 (23.3:1 with tandem booster), enabling rapid ram deployment to seal the wellbore. Pipe rams feature precision-machined profiles to match specific pipe diameters, while shear rams (model SBR3570CC.00) are engineered to cut drill pipe under full pressure, providing emergency well isolation. Variable bore rams (VBR3570CA.00 and VBR3570CB.00) adapt to multiple pipe sizes (2 7/8"-5" and 4 1/2"-7" respectively) to reduce tool change time.

3.2 Sealing Mechanisms

Dual sealing protection is achieved through primary and secondary sealing systems. Primary seals include top, front, and piston rod seals (Y-rings, U-seals, and O-rings) designed for high-pressure resistance and wear durability. The secondary sealing mechanism uses grease injection (EM-09-01 grease) via check valves and plug cocks to reinforce sealing integrity during primary seal degradation. Bonnet seals (floating seal assembly 2C12.08.00) prevent pressure leakage at the ram housing interface, with floating seal skeletons ensuring uniform pressure distribution.

3.3 Hydraulic Actuation

The hydraulic cylinder assembly (standard and tandem booster configurations) drives ram movement, with U-seals and backup rings preventing hydraulic fluid leakage. Tandem boosters enhance closing force for heavy-duty applications, increasing the closing ratio to 23.3:1. Locking screws (39 turns per end) mechanically secure rams in the closed position, eliminating reliance on hydraulic pressure for long-term sealing. Ram change cylinders facilitate quick ram replacement, reducing maintenance downtime.

4. Structural Features

4.1 Robust Body Design

The BOP body is fabricated from forged alloy steel, offering exceptional mechanical strength and corrosion resistance. It features a compact design with a 346.1mm (13 5/8") bore to accommodate standard drill pipe sizes, with nozzle flanges for connection to choke and kill lines. The single ram model (FZ35-35U) weighs 6450kg, while the double ram model (2FZ35-35U) weighs 10764kg, both optimized for easy installation on drill floors and wellheads.

4.2 Modular Ram System

The modular ram design allows for quick interchange between pipe, shear, and variable bore rams, with standardized mounting interfaces reducing tooling complexity. Ram assemblies include replaceable top and front seals, enabling targeted maintenance without full ram replacement. Shear ram bodies (upper and lower) are heat-treated for enhanced cutting performance, while variable bore rams use flexible front packers to adapt to different pipe diameters.

4.3 Redundancy & Safety

The 2FZ35-35U double ram model incorporates dual ram assemblies for redundant sealing, critical for high-risk operations. All hydraulic components meet API RP 53 (Recommended Practice for Well Control Equipment Systems for Drilling Wells) standards, with check valves preventing backflow in the secondary sealing system. Locking screws provide mechanical backup to hydraulic actuation, ensuring rams remain closed during power failures.

5. Applicable Working Conditions

The FZ35-35U series BOPs are engineered for onshore and shallow offshore drilling operations, compatible with the following conditions:

Pressure Range: Rated working pressure of 35MPa (5000psi), suitable for medium-pressure formations (up to 52.5MPa hydrostatic test pressure).

Temperature Rating: T-20 rating, operational in temperatures from -20℃ to +121℃ (-4℉ to 250℉), compatible with most drilling fluids including water-based, oil-based, and synthetic muds.

Wellbore Sizes: Accommodates 2 3/8"-11 3/4" drill pipes and casings, ideal for vertical and deviated wells (up to 45° inclination).

Environmental Conditions: Corrosion-resistant design for humid, dusty, and coastal environments, with sealing components resistant to drilling fluid contamination.

Operation Types: Drilling, completion, workover, and well testing operations, including emergency well control scenarios.

6. Maintenance & Care Recommendations

6.1 Routine Maintenance

Daily Inspections: Check hydraulic lines for leaks, verify ram position indicators, and inspect secondary sealing grease levels. Test the hydraulic actuation system to ensure smooth ram movement (open/close cycles).

Weekly Checks: Inspect primary seals (O-rings, U-seals) for wear, cracks, or deformation; replace damaged seals immediately. Clean nozzle flanges and check bolt torque to prevent pressure leakage. Test the locking screw mechanism for proper engagement.

Monthly Servicing: Flush the hydraulic system to remove contaminants; replace hydraulic fluid if discolored or contaminated. Calibrate pressure gauges and test the secondary sealing grease injection system. Inspect ram faces for wear and damage.

6.2 Preventive Maintenance

Adhere to API RP 53 and manufacturer guidelines for preventive maintenance scheduling. Replace all primary seals every 6 months or 500 operating hours (whichever comes first). Conduct non-destructive testing (ultrasonic) on the BOP body annually to detect internal cracks. Refill secondary sealing grease every 3 months, and replace shear ram blades after one emergency cut or 1000 operating hours.

6.3 Storage & Handling

Store BOPs in a clean, dry environment, with rams in the open position to prevent seal compression. Cover nozzle flanges and hydraulic ports to prevent contamination. When transporting, secure the BOP to avoid vibration damage to seals and hydraulic components. Before reinstallation, inspect all seals and lubricate moving parts with compatible grease (EM-09-01).

FZ35-35U Ram BOP

Specification and Main Technical Parameters of Ram-type Blowout Preventer

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

Hydraulic Cylinder Assembly Parts List

Parts List for Hydraulic Cylinder Assembly with Tandem Booster

Parts List for Hydraulic Cylinder Assembly with Tandem Booster

One-year recommended spare parts list

7. Field Fault Repair Cases

Case 1: Primary Seal Leakage

Issue: Pressure leakage at the ram front seal during well testing with the FZ35-35U BOP. Root Cause: Drilling fluid contamination (sand particles) caused wear to the front seal (part 2C02.01A.02).Solution: Replaced the front seal and cleaned the ram face; flushed the hydraulic system to remove contaminants. Applied secondary sealing grease to reinforce the seal. Preventive Action: Added a filter to the drilling fluid circulation system and increased frequency of seal inspections in sandy formations.

Case 2: Hydraulic Actuation Failure

Issue: Ram failed to close on the 2FZ35-35U BOP. Root Cause: Clogged hydraulic filter in the tandem booster assembly, restricting fluid flow to the cylinder. Solution: Replaced the hydraulic filter (part 47), flushed the system, and tested actuation cycles. Adjusted hydraulic pressure to the recommended 9.5MPa. Preventive Action: Replaced hydraulic filters every 3 months and installed a pressure bypass valve to prevent system blockages.

Case 3: Secondary Sealing Malfunction

Issue: Secondary sealing grease failed to inject, compromising seal integrity. Root Cause: Clogged check valve (part SFZ1310-32.00) due to dried grease buildup. Solution: Disassembled and cleaned the check valve; replaced old grease with EM-09-01 secondary seal grease. Tested the injection system to ensure smooth grease flow. Preventive Action: Flushed the secondary sealing system every 2 months and stored grease in a temperature-controlled environment.

Case 4: Ram Locking Screw Jam

Issue: Locking screws failed to engage after closing the ram on the FZ35-35U BOP. Root Cause: Corrosion and debris buildup on the screw threads, caused by exposure to saltwater in a coastal drilling site. Solution: Cleaned the threads with a wire brush, applied anti-corrosion lubricant, and manually rotated the screws to ensure smooth operation. Preventive Action: Coated locking screws with anti-corrosion lubricant monthly and covered the BOP during idle periods to prevent saltwater exposure.

8. FAQ (Frequently Asked Questions)

9. Procurement Guidance & Conclusion

The FZ35-35U and 2FZ35-35U Ram-Type BOPs are API-compliant, reliable well control solutions tailored to medium-pressure drilling operations, addressing the safety and efficiency needs of E&P companies, drilling contractors, and well service providers. Their robust design, modular ram system, and dual sealing mechanisms ensure compliance with global HSE standards and industry best practices, minimizing blowout risks and operational downtime.

When procuring, verify that all components include API certification marks and comply with local regulatory requirements (e.g., GB/T 22513, OSHA well control standards). Prioritize suppliers offering comprehensive technical documentation, one-year recommended spare parts kits, and on-site maintenance training. The recommended spare parts list (included in the technical data) ensures critical components are available for quick replacement, reducing downtime.

For operations requiring reliable well control, the FZ35-35U series delivers proven performance backed by rigorous testing, API certification, and real-world field validation. We invite you to consult our technical team to customize ram configurations (pipe, shear, VBR) to your specific wellbore requirements, discuss procurement terms, and access detailed performance data and client references. Invest in a well control solution that aligns with industry standards and safeguards your personnel, equipment, and environment.

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.