Core Purpose & Equipment Adaptation
This guide is tailored for FZ18-35, 2FZ18-35, FZ23-35, 2FZ23-35, FZ35-35, and 2FZ35-35 steam-heated ram blowout preventers (BOPs)—critical well control equipment for high-temperature oil and gas drilling. It addresses the needs of drilling contractors, maintenance technicians, and procurement teams, providing model-specific insights to ensure API 16A-compliant operation, mitigate downtime from thermal wear, and maintain sealing integrity in harsh downhole environments.
Product Overview
The FZ series steam-heated ram BOPs are designed for 35MPa (5000psi) rated working pressure, with hydrostatic test pressure up to 52.5MPa (7500psi). Available in single (FZ) and double (2FZ) ram configurations, they cover bore sizes from 179.4mm (7 1/16 in) to 346.1mm (13 5/8 in), catering to diverse casing and tubing specifications. The steam heating function enables stable operation in low-temperature well sites, while metal materials meet T-75 temperature grade standards for extreme thermal resilience.
Functional Characteristics
These BOPs feature precise ram actuation controlled by hydraulic systems (21MPa rated, 8.4-10.5MPa recommended operation pressure) for rapid well sealing. Equipped with mechanical locking systems (13.5-24 locking screw turns per end), they ensure secure ram positioning after closing. The secondary seal system and multi-layer shaft seals enhance leak resistance, while model-specific closing ratios (3.6-5.7) optimize force transmission for efficient sealing under high pressure.
Structural Features
The BOPs adopt a robust modular structure, including a one-piece alloy steel body for high-pressure resistance and corrosion durability. Ram assemblies (blind and pipe-specific) are interchangeable for versatile well control, with face and top seals made of high-temperature-resistant elastomers. Ram shaft and locking shaft seal assemblies integrate V-rings, W-rings, and lip seals to prevent fluid leakage. Double ram models (2FZ) offer redundant sealing for critical drilling scenarios, reducing failure risks.
Applicable Working Conditions
Ideal for onshore and offshore high-temperature oil and gas wells, especially those requiring steam assistance for viscosity reduction. Suitable for wells with working temperatures matching T-75 metal grade standards, and compatible with casing/tubing sizes from 2 3/8” to 9 5/8”. Widely used in heavy oil development, deep well drilling, and areas with low ambient temperatures where steam heating prevents seal hardening and operational jamming.
Maintenance & Care Recommendations
Conduct weekly inspections of hydraulic lines and seal integrity to detect leaks early. Lubricate locking screws and ram shafts with high-temperature grease (EM-09-1 for secondary seals) every 50 operating cycles. Replace elastomeric seals (O-rings, V-rings, side door seals) every 6 months or if swelling, cracking, or wear is detected. Perform hydrostatic tests annually per API 16A § 10.3 to verify pressure resistance. Store spare parts in low-humidity environments to avoid elastomer aging.
Description | FZ18-35 Part No./Model |
Body | 1 |
Ram Assembly | 2 |
Door bolt | 2S91.07 |
O-ring | 34.4×3.1 |
Screw | GB/T 5782 M12×75 |
Hinge Screw | 2S91.08 |
Hinge Block （two） | 2S91.06 |
O-ring | 24.4×3.1 |
Hinge Block （one） | 2S91.05 |
NPT 1" Plug | 2S91.10 |
Plug | SFZ1310-01 |
Right Cylinder head | 2S91.03.02.00 |
Left Cylinder head | 2S91.04.02.00 |
O-ring | 148.59×5.33 |
Locking Shaft Seal Assembly | See 3.2.5 |
Hydraulic cylinder | 2S91.03.05 |
Screw | GB/T71 M8×16 |
Locking nut | 2S91.03.07 |
Piston | 2S91.03.06 |
Piston O-ring | 69.4×3.1 |
Piston Seal | 2S91.03.12 |
Right Door | 2S91.03.01 |
Left Door | 2S91.04.01 |
Ram Shaft Seal Assembly | See 3.2.3 |
Ram shaft | 2S91.03.03 |
Side Door Seal | 253.37×6.99 |
Plug | 2C01.36 |
O-ring | 24.4×3.1 |
Locking screw | 2S91.03.04 |
Cylinder Bolt | 2S91.03.13 |
Cap Nut | 2S91.03.14 |
Parts List for FZ23-35/FZ35-35
Description | FZ23-35 Part No./Model | FZ35-35 Part No./Model |
Body | 1 | 1 |
Ram Assembly | 2 | 4 |
Door bolt | 2S84.06 | 2S84.06 |
O-ring | 43.7×3.55 | 43.7×3.55 |
Screw | GB5780 M20×100 | GB5780 M20×100 |
Locating Pin | GB120 A16×60 | GB118-86 A16×60 |
Hinge Screw | 2S84.09 | 2S84.09 |
Hinge Block | 2S84.05 | 2S85.05 |
O-ring | 34.5×3.55 | 34.5×3.55 |
Plug | 2C01.21 | 2C01.21 |
Screw | GB5780 M16×50 | GB5780 M16×50 |
Plug | SFZ1310-01 | SFZ1310-01 |
Nozzle flange | 2S84.10 | 2S84.10 |
Right Cylinder head | 2S84.03.02 | 2S85.03.02 |
Left Cylinder head | 2S84.04.02 | 2S85.04.02 |
O-ring | 206×5.3 | 239×5.3 |
Locking Shaft Seal Assembly | See 3.2.5 | -- |
Hydraulic cylinder | 2S84.03.05 | 2S85.03.05 |
Screw | GB71-85 M8×16 | GB79-85 M8×25 |
Locking nut | 2S84.03.07 | 2S85.03.07 |
Piston | 2S84.03.06 | 2S85.03.06 |
Piston O-ring | 80×3.55 | 103×5.3 |
Piston Seal | 2S84.03.12 | 2S85.03.12 |
Right Door | 2S84.03.01 | 2S85.03.01 |
Left Door | 2S84.04.01 | 2S85.04.01 |
Secondary Seal System | See 3.2.4 | -- |
Ram Shaft Seal Assembly | See 3.2.3 | -- |
Locating Pin | 2S84.07 | 2S85.07 |
Ram shaft | 2S84.03.03 | 2S85.03.03 |
Side Door Seal | 2S84.03.24 | 2S85.03.16 |
Plug | 2C01.36 | 2C01.36 |
O-ring | 31.5×3.55 | 31.5×3.55 |
Locking screw | 2S84.03.04 | 2S85.03.04 |
Cylinder Bolt | 2S84.03.13 | 2S85.03.13 |
Cap Nut | 2S84.03.14 | 2S85.03.14 |
FZ18-35 Spare Parts list for one year
Description | FZ18-35 Part No./Model |
O-ring | 34.4×3.1 |
O-ring | 24.4×3.1 |
O-ring | 148.59×5.33 |
O-ring | 73.02×3.53 |
O-ring | 49.2×3.53 |
Wiper Ring | 2S91.03.16 |
Piston O-ring | 69.4×3.1 |
Piston Seal | 2S91.03.12 |
V-ring for ram shaft | 2S91.03.09 |
O-ring | OR-NBR70 79.6×5.7 |
Ram shaft seal | 2S91.03.11 |
Side Door Seal | 253.37×6.99 |
O-ring | 24.4×3.1 |
FZ23-35/FZ35-35 Spare Parts list for one year
Description | FZ23-35 Part No./Model | FZ35-35 Part No./Model |
O-ring | 43.7×3.55 | 43.7×3.55 |
O-ring | 34.5×3.55 | 34.5×3.55 |
O-ring | 206×5.3 | 239×5.3 |
Lip ring cover | 2FZ1870DBYS.03-23 | 2FZ1870DBYS.03-23 |
Lip ring | 2FZ1870DBYS.03.22-00 | 2FZ1870DBYS.03.22-00 |
Wiper ring | 2S84.03.19 | 2S84.03.19 |
O-ring | 80×3.55 | 103×5.3 |
Piston Seal | 2S84.03.12 | 2S85.03.12 |
Secondary sealing grease | EM-09-1 | EM-09-1 |
W-ring | 2S84.03.09 | 2S85.03.09 |
W-ring | 2S84.03.10 | 2S85.03.10 |
O-ring | 103×3.55 | 125×3.55 |
O-ring | 92×3.55 | 109×2.65 |
Ram shaft seal | 2S84.03.25 | 2S85.03.17 |
Side Door Seal | 2S84.03.24 | 2S85.03.16 |
O-ring | 31.5×3.55 | 31.5×3.55 |
Field Fault Repair Cases
Case 1: Ram Shaft Seal Leakage (FZ18-35)
Symptom: Hydraulic fluid leakage at the ram shaft during operation. Root Cause: V-rings (2S91.03.09) aged and hardened due to long-term steam exposure, losing elasticity. Repair: Replaced V-rings with genuine parts, cleaned the shaft surface, and applied high-temperature lubricant. Preventive Measure: Inspect V-rings monthly; replace every 6 months in high-steam environments.
Case 2: Secondary Seal Failure (FZ23-35)
Symptom: Poor sealing performance after ram closing. Root Cause: Secondary sealing grease (EM-09-1) depleted, and check valve (2S84.03.23.00) clogged. Repair: Refilled EM-09-1 grease, cleaned the check valve, and tested seal integrity. Preventive Measure: Replenish grease every 3 months; clean valves during routine maintenance.
Case 3: Locking Shaft Jamming (FZ35-35)
Symptom: Unable to lock/unlock ram after actuation. Root Cause: Lip ring (2FZ1870DBYS.03.22-00) worn, causing shaft misalignment and debris accumulation. Repair: Replaced lip ring and wiper ring, realigned the locking shaft, and removed debris. Preventive Measure: Clean the locking shaft assembly every 2 months; monitor wear on lip rings.
Case 4: Piston Seal Leakage (2FZ18-35)
Symptom: Reduced hydraulic pressure during ram actuation. Root Cause: Piston seals (2S91.03.12) damaged by pressure pulsation and improper lubrication. Repair: Replaced piston seals and O-rings (69.4×3.1), applied compatible grease, and adjusted hydraulic operation pressure to 9MPa. Preventive Measure: Maintain operation pressure within 8.4-10.5MPa; lubricate pistons before each use.
FAQ
Question | Answer |
Can ram assemblies be cross-used between FZ23-35 and FZ35-35 models? | No. FZ23-35 uses 2S84-series ram parts, while FZ35-35 uses 2S85-series parts. Their dimensions and bore sizes differ (228.6mm vs 346.1mm), so cross-use causes sealing failure and structural damage, violating API 16A safety norms. |
What is the difference between single (FZ) and double (2FZ) ram BOPs? | Single ram models have one set of rams for sealing, suitable for standard well control. Double ram models have two independent ram sets, providing redundant sealing—critical for high-risk scenarios like heavy oil steam drilling, where primary seal failure could lead to well blowouts. |
How to select the correct pipe ram for specific tubing sizes? | Match the tubing size to model-specific ram part numbers: FZ18-35 uses 2S91-series rams (e.g., 2S91.01B.00 for 3 1/2”), FZ23-35 uses 2S84-series (e.g., 2S84.01F.00 for 6 5/8”), and FZ35-35 uses 2S85-series (e.g., 2S85.01I.00 for 9 5/8”). Refer to the pipe ram parts list for precise matching. |
Why is the recommended hydraulic operation pressure limited to 8.4-10.5MPa? | Exceeding 10.5MPa causes excessive wear on piston seals and ram shafts, reducing component lifespan. Below 8.4MPa, the closing force is insufficient to achieve tight sealing under 35MPa well pressure. This range balances sealing efficiency and component durability per manufacturer and API 16A guidelines. |
What type of lubricant is compatible with the secondary seal system? | Only use EM-09-1 secondary sealing grease. It resists high temperatures (up to T-75 grade) and maintains viscosity under steam exposure. Substitute lubricants may react with elastomer seals, causing swelling or degradation and compromising leak resistance. |
Procurement Guidance
Genuine parts and proper maintenance are critical for the safe and reliable operation of FZ series steam-heated ram BOPs. We supply all model-specific components—including ram assemblies, seals, hydraulic parts, and secondary seal systems—fully compliant with API 16A and T-75 temperature grade standards. Each part comes with traceable material certificates to ensure compatibility and durability. Our technical team provides personalized spare parts inventory plans and maintenance consultations based on your drilling conditions and equipment model. Contact us to secure authentic parts that minimize downtime, maintain well control integrity, and support efficient high-temperature drilling operations.
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