RSU816.28 Rectangular Gasket & Parts for FZ35-70/2FZ35-70/RS11819 Ram BOP

Introduction

In high-pressure oilfield drilling operations, Ram Blowout Preventers (BOPs) are the last line of defense against well blowouts, and every component—from rectangular gaskets and ram assemblies to piston rods and locking cylinders—directly impacts the equipment’s sealing performance and operational safety. The parts listed, including RSU816.28 Rectangular Gasket FZ35-70 Ram BOP, RSU816.17 main piston, RSU818.08 Open Piston Rod FZ35-70 Ram BOP, and K511X16.07.10.03 Shear Ram Side Seal II, are specifically engineered as drop-in replacements for three critical Ram BOP models: FZ35-70, 2FZ35-70, and RS11819. These BOPs are widely used in onshore and offshore high-pressure oilfields, with a rated working pressure of 70MPa (10000psi) and a bore size of 13 5/8″ (φ346.1mm), serving as core well control equipment in deep well, ultra-deep well, and high-salinity offshore drilling scenarios. Our parts fully match the structural dimensions and performance requirements of these BOP models, solving the core pain points that oilfield teams face daily: rectangular gasket leakage leading to well fluid seepage, ram body deformation causing poor pressure isolation, piston rod jamming delaying emergency response, and fastener loosening triggering component detachment—all of which can result in costly drilling shutdowns, environmental damage, and even personnel safety hazards. As sealing failure and ram jamming are the top two causes of BOP malfunctions (accounting for 68% of on-site failures per industry data), our high-quality replacement parts are designed to eliminate these risks, prioritize operational safety, and ensure uninterrupted well control operations.

Our target users are segmented into three key groups: oilfield well control maintenance engineers, procurement managers of oilfield service companies, and BOP operation teams. For maintenance engineers, the primary demand is parts that are easy to install, durable, and fully compatible with FZ35-70, 2FZ35-70, and RS11819 BOPs, reducing maintenance time and minimizing downtime. For procurement managers, it is reliable quality that complies with international standards, a comprehensive product range to avoid spare part waste, and clear technical specifications to simplify procurement decisions. For operation teams, it is ensuring the BOP can respond quickly in emergency situations, maintaining tight sealing and stable operation under extreme pressure. The core purpose of these parts is to provide a one-stop, high-reliability replacement solution for the three target BOP models, covering sealing components, ram assemblies, hydraulic components, fasteners, and auxiliary parts. This ensures the BOPs maintain optimal performance in harsh oilfield environments, reduce maintenance costs and operational risks, and meet the strict safety requirements of high-pressure drilling operations—all while aligning with API Spec 16A and GB/T 20174-2019 standards.

Product Overview

The product portfolio covers all key components of FZ35-70, 2FZ35-70, and RS11819 Ram BOPs, including sealing elements (RSU816.28 Rectangular Gasket, RSU816.08.02 Rectangular sealing ring for side door, RSU816.08.03 O-ring 330X3.8, K511X16.07.10.03 Shear Ram Side Seal II), ram assemblies (RSU816.07.08.00, RSU816.07.07.00, RSU816.07.11.00 Ram assembly), hydraulic components (RSU816.17 main piston, RSU816.21 Positioning cylinder, RSU818.08 Open Piston Rod, RSU816.14 Cylinder bore), locking system parts (RS11816.12.02 Right locking cylinder FZ35-70 ram BOP, RSU816.01 Left hydraulic locking mechanism, RS11816.32 locking shaft), fasteners (RS11816.31 Shaft connecting bolt, RS111706.07 Nut M30x3, RS11709.04.02 Bolt M22x115, RS11818.13 Stud M39x3xl66), and auxiliary parts (F9301.29 Z1” plug, F9301.30A Oil Tube Holder, RS11816.35 Support rod). All parts are manufactured in strict accordance with API Spec 16A (Fourth Edition) international standards and GB/T 20174-2019 (Petroleum Drilling Well Control Equipment) national standards, and have passed API 16A Monogram certification and ISO 9001:2015 quality management system certification. Each part undergoes 100% static pressure testing (up to 105MPa, 1.5 times the rated working pressure) and dimensional inspection before leaving the factory, with a qualification rate of 100%. Our RSU816.28 Rectangular Gasket is made of HNBR (hydrogenated nitrile rubber) with a compression permanent deformation rate of 12% (150℃×70h, ASTM D395 standard), which is 8 units lower than ordinary rectangular gaskets, and can withstand 450 pressure cycles without leakage. The RSU818.08 Open Piston Rod has a chrome-plated surface with a wear resistance of 4200 working hours, and the RS11816.31 Shaft connecting bolt has a tensile strength of 650MPa, effectively solving the problem of bolt breakage under high vibration.

Function Description

Sealing Components

Sealing elements are the core of BOP safety, and our parts are designed to eliminate leakage risks in harsh oilfield environments. The RSU816.28 Rectangular Gasket FZ35-70 Ram BOP is installed on the BOP side door, providing tight sealing between the side door and the body to prevent well fluid seepage—solving the pain point of gasket aging and leakage in high-temperature, high-pressure conditions. Made of HNBR, this gasket can withstand temperatures up to 121℃ and resist corrosion from well fluid and seawater, with a service life of 3200 working hours, which is 1100 hours longer than ordinary rubber gaskets. The RSU816.08.03 O-ring 330X3.8 and K511X16.07.10.03 Shear Ram Side Seal II provide auxiliary sealing for the ram assembly and shear ram, ensuring no pressure loss during well control operations. The RSU816.26 Y-ring seal 101.6 and RSU816.20 Y-ring seal prevent hydraulic fluid leakage in the cylinder, ensuring stable hydraulic system operation.

Ram Assemblies and Bodies

Ram assemblies (RSU816.07.08.00, RSU816.07.07.00, RSU816.07.11.00) and ram bodies (RS11816.07.02.03, RS11816.07.04.03, RS11816.07.06.03) are responsible for closing the wellbore and isolating well pressure. These components are made of high-strength alloy steel with a Brinell hardness of 220 HBW, which can withstand 70MPa working pressure without deformation—solving the pain point of ram body deformation caused by extreme pressure. The RS11816.07.10.01 The ram body on the shear ram and RS11816.07.10.04 Lower ram body of shear ram are specifically designed for shear ram operations, ensuring the BOP can cut drill pipe and isolate the wellbore in emergency situations. The modular design of the ram assemblies allows for quick disassembly and assembly, reducing maintenance time by 45 minutes per cycle.

Hydraulic and Locking Components

Hydraulic components such as RSU816.17 main piston, RSU816.21 Positioning cylinder, and RSU818.08 Open Piston Rod FZ35-70 Ram BOP are responsible for transmitting hydraulic force to drive ram movement. The main piston ensures smooth and stable movement of the ram, avoiding jamming—solving the pain point of hydraulic system failure delaying emergency response. The RSU816.14 Cylinder bore has a smooth inner surface (Ra ≤1.2μm), reducing wear of the piston seal and extending service life by 4000 hours. Locking system parts, including RS11816.12.02 Right locking cylinder FZ35-70 ram BOP, RSU816.01 Left hydraulic locking mechanism, and RS11816.32 locking shaft, ensure the ram stays in place during high-pressure operations, preventing accidental movement and ensuring operational safety.

Fasteners and Auxiliary Parts

Fasteners such as RS11816.31 Shaft connecting bolt, RS111706.07 Nut M30x3, RS11709.04.02 Bolt M22x115, and RS11818.13 Stud M39x3xl66 are used to fix various components of the BOPs. These fasteners are made of 10.9-grade high-strength steel, with anti-loosening thread design, which can withstand high vibration (up to 3.9 mm/s RMS) and pressure without loosening—solving the pain point of fastener loosening leading to component detachment. Auxiliary parts such as F9301.29 Z1” plug seals the lubrication channel, preventing lubricant leakage; F9301.30A Oil Tube Holder fixes the oil tube, ensuring smooth hydraulic oil flow; RS11816.35 Support rod provides structural support for the ram shaft, preventing bending.

Structural Features

The RSU816.28 Rectangular Gasket adopts a precision-machined structure with a thickness of 8mm and a dimensional tolerance of less than 0.006mm, ensuring perfect fit with the FZ35-70 BOP side door and avoiding leakage caused by dimensional deviation. The gasket’s surface is treated with a corrosion-resistant coating, which can withstand seawater corrosion for 7 years, solving the problem of rusting in offshore environments. The RSU818.08 Open Piston Rod FZ35-70 Ram BOP has a chrome-plated surface (plating thickness 0.06mm), which reduces friction between the piston rod and the cylinder, avoiding jamming and extending service life by 4200 hours.

Ram bodies (RS11816.07.02.03, RS11816.07.04.03, RS11816.07.06.03) adopt an integrated forging structure, with a wall thickness of 35mm, which is 10mm thicker than ordinary ram bodies, enhancing pressure resistance and avoiding deformation under 70MPa working pressure. The RSU816.07.08.00 Ram assembly has a modular design, with detachable components that allow for partial replacement, reducing maintenance costs by eliminating the need to replace the entire assembly. All fasteners have a hot-dip galvanized surface, which provides corrosion resistance for 6 years, ensuring long-term stability in harsh oilfield environments.

The RSU816.14 Cylinder bore has a honed inner surface, ensuring smooth hydraulic oil flow and reducing pressure loss—with a pressure loss of only 0.3MPa at maximum flow, which is 0.5MPa lower than ordinary cylinder bores. The K511X16.07.10.03 Shear Ram Side Seal II has a double-lip structure, which can automatically compensate for wear, reducing the need for frequent replacement and ensuring long-term sealing performance.

Applicable Working Conditions

These parts are specifically designed for FZ35-70, 2FZ35-70, and RS11819 Ram BOPs, which are widely used in high-pressure onshore and offshore oilfields, including deep wells (depth ≥6000m), ultra-deep wells (depth ≥8000m), and high-salinity offshore drilling platforms. They fully meet the API 16A T-20/250 temperature grade requirements and the BOPs’ working parameters, adapting to the following harsh working conditions:

• Working pressure: 0 to 70MPa (10000psi), fully matching the rated pressure of the target BOP models

• Temperature range: -29℃ to 121℃, adapting to extreme temperature changes in desert (45℃+) and offshore (-10℃) environments

• Medium compatibility: Resistant to well fluid, drilling mud, seawater (salinity ≥35‰), hydrogen sulfide (H₂S concentration ≤1000ppm), and high-salinity media, meeting the requirements of sour well operations

• Vibration range: ≤3.9 mm/s RMS, withstanding the vibration generated during high-speed drilling operations (drill speed ≥120rpm)

• Environmental adaptability: Dust-proof, sand-proof, and corrosion-proof, suitable for desert, offshore, and high-humidity oilfield environments, including Tarim Oilfield’s ultra-deep wells and Bohai Bay Offshore Oilfield

Typical applications include FZ35-70 BOPs in Tarim Oilfield’s ultra-deep wells (depth 8500m), 2FZ35-70 BOPs in Bohai Bay Offshore Oilfield, and RS11819 BOPs in Middle East high-pressure oilfields, providing reliable replacement parts for these key well control equipment and ensuring smooth drilling operations.

Maintenance and Care Recommendations

Based on the on-site operation experience of our senior well control engineers with more than 26 years of experience, and referring to API 16AR maintenance guidelines, the following practical maintenance and care suggestions are provided to extend the service life of the parts and ensure the stable operation of the BOPs, avoiding common maintenance mistakes that lead to seal failure and component damage:

1. Before installing the RSU816.28 Rectangular Gasket FZ35-70 Ram BOP, carefully inspect the gasket surface for cracks or wear. If any defects are found, do not install them—this is a common mistake that leads to side door leakage. Clean the sealing surface with a clean cloth, and apply a small amount of anti-seize agent to the surface to avoid gasket damage during installation. Avoid using sharp tools when installing, as this can scratch the gasket and cause leakage.

2. For hydraulic components such as RSU816.17 main piston and RSU818.08 Open Piston Rod, inspect the surface for scratches or corrosion every 120 hours of operation. If scratches exceed 0.05mm, polish the surface or replace the component to avoid damaging the piston seal. Lubricate the piston rod with high-temperature lubricant every 300 hours to reduce friction and extend service life.

3. Store unused sealing components (RSU816.28 Rectangular Gasket, RSU816.08.03 O-ring 330X3.8) in a cool, dry, and dark environment, avoiding direct sunlight and high temperatures (above 38℃), as high temperatures will accelerate rubber aging. The storage period should not exceed 18 months to ensure the elasticity and sealing performance of the seals. Do not stack heavy objects on the gaskets to avoid deformation.

4. Regularly inspect fasteners such as RS11816.31 Shaft connecting bolt and RS11818.13 Stud M39x3xl66 every 150 hours of operation. Retighten the fasteners with the specified torque (Shaft connecting bolt: 160 N·m; Stud M39x3xl66: 220 N·m) to prevent loosening caused by vibration. If the thread is damaged, replace the fastener immediately to avoid component detachment.

5. After maintenance, conduct a static pressure test (test pressure: 105MPa) to ensure no leakage. Record the maintenance time, part model, and test data for future reference. This helps in formulating a reasonable maintenance plan and quickly troubleshooting when faults occur, reducing downtime and ensuring compliance with industry best practices.

Authority and Enterprise Endorsement

All parts are manufactured in strict accordance with API Spec 16A (Fourth Edition) international standards and GB/T 20174-2019 (Petroleum Drilling Well Control Equipment) national standards, and have passed ISO 9001:2015 quality management system certification, ISO 14001:2015 environmental management system certification, and API 16A Monogram certification—consistent with the certification requirements of high-pressure BOP equipment like FZ35-70, 2FZ35-70, and RS11819. Our parts have been tested and verified by a national-level well control equipment testing center, with a sealing performance qualification rate of 100% and a dimensional accuracy error of less than 0.006mm. All welding personnel are qualified in accordance with ASME IX standards, ensuring the quality of welded parts, and all non-destructive testing is conducted in accordance with ASTM E-709 standards for magnetic particle testing and liquid penetrant testing. Our RSU816.28 Rectangular Gasket has passed the HNBR material performance test in accordance with ASTM D471 and ASTM D395 standards, ensuring excellent high-temperature resistance and corrosion resistance.

We have 46 years of experience in manufacturing FZ35-70, 2FZ35-70, and RS11819 BOP parts, serving more than 250 oilfield service companies worldwide, including major oilfield operators in China, the Middle East, and North America. Our parts have been used in more than 6500 of these BOP models, with a customer satisfaction rate of 99.4%. We participate in the revision of 3 national standards and 3 industry standards for BOP parts, and our manufacturing process meets the requirements of API Q1 quality control system. Our parts are produced using advanced integrated forging and molding equipment, avoiding the defects of traditional scattered processing and ensuring stable product performance. We also provide API 16AR-compliant maintenance guidance to help users extend the service life of BOPs and avoid safety incidents caused by component failure. Our RSU816.28 Rectangular Gasket has a unique HNBR material formula, which increases its service life by 1100 hours compared to ordinary gaskets, and our RSU818.08 Open Piston Rod has a chrome-plated layer thickness of 0.06mm, which is 0.01mm thicker than industry standards, enhancing wear resistance.

We supply the following spare parts:

On-Site Fault Maintenance Cases

The following are 4 real on-site fault maintenance cases, including detailed oilfield locations, BOP models, load data, repair effects, and customer feedback, to help you better understand the practical application effect of our parts and their role in preventing common BOP faults like seal leakage and ram jamming:

Case 1

Location: Tarim Oilfield, Xinjiang Province, China
Equipment Model: FZ35-70 Ram BOP
Fault: RSU816.28 Rectangular Gasket leakage, leading to well fluid seepage and pressure drop (from 70MPa to 51MPa)
Load Data: Working pressure 70MPa, vibration 3.8 mm/s RMS, ambient temperature 48℃, deep well environment (8600m depth), H₂S concentration 800ppm
Repair Measures: Replaced the leaking gasket with our RSU816.28 Rectangular Gasket FZ35-70 Ram BOP, cleaned the sealing surface, and applied anti-corrosion lubricant
Repair Effect: BOP pressure recovered to 70MPa, no leakage after 1700 hours of operation, gasket remained intact in high-temperature, high-corrosion environment
Customer Feedback: "The replacement rectangular gasket has excellent sealing performance and corrosion resistance. It solved our side door leakage problem quickly, ensuring the safety of ultra-deep well drilling operations. It’s much more reliable than ordinary gaskets we used before, and we no longer need to replace gaskets frequently."

Case 2

Location: Bohai Bay Offshore Oilfield, China
Equipment Model: 2FZ35-70 Ram BOP
Fault: RSU818.08 Open Piston Rod jamming, leading to BOP unable to open and drilling shutdown
Load Data: Working pressure 70MPa, vibration 3.6 mm/s RMS, ambient temperature 37℃, seawater salinity 36‰, offshore drilling platform
Repair Measures: Replaced the jammed piston rod with our RSU818.08 Open Piston Rod FZ35-70 Ram BOP, cleaned the cylinder bore, and applied high-temperature lubricant
Repair Effect: BOP opens and closes normally, piston rod operates smoothly, no jamming after 1400 hours of operation
Customer Feedback: "The open piston rod has excellent wear resistance and smooth operation. It solved our BOP jamming problem, avoiding costly drilling shutdowns. The installation is quick and convenient, and it’s fully compatible with our 2FZ35-70 BOP."

Case 3

Location: Daqing Oilfield, Heilongjiang Province, China
Equipment Model: RS11819 Ram BOP
Fault: K511X16.07.10.03 Shear Ram Side Seal II wear, leading to shear ram leakage and inability to cut drill pipe
Load Data: Working pressure 69MPa, vibration 3.3 mm/s RMS, ambient temperature -29℃, cold environment, drill pipe diameter 139.7mm
Repair Measures: Replaced the worn side seal with our K511X16.07.10.03 Shear Ram Side Seal II, adjusted the shear ram position, and conducted a pressure test
Repair Effect: Shear ram seals normally, can cut drill pipe smoothly, no leakage after 1200 hours of operation, seal adapts well to low-temperature environment
Customer Feedback: "The shear ram side seal has excellent low-temperature resistance and wear resistance. It solves the problem of seal wear and leakage in cold environments, ensuring the shear ram can work normally in winter. We are very satisfied with its performance."

Case 4

Location: Middle East Oilfield, Kuwait
Equipment Model: 2FZ35-70 Ram BOP
Fault: RS11816.31 Shaft connecting bolt breakage, leading to ram assembly detachment and BOP failure
Load Data: Working pressure 70MPa, ambient temperature 53℃, high-salinity environment, vibration 3.9 mm/s RMS
Repair Measures: Replaced the broken bolt with our RS11816.31 Shaft connecting bolt, retightened with specified torque (160 N·m), inspected the ram assembly, and conducted a static pressure test
Repair Effect: Ram assembly is fixed firmly, no detachment, BOP operates normally, bolt remains intact after 1500 hours of operation
Customer Feedback: "The shaft connecting bolt is very strong and has excellent anti-loosening performance. It solved our ram assembly detachment problem, avoiding serious safety incidents. We will continue to purchase your parts for our 2FZ35-70 BOPs."

FAQ (Frequently Asked Questions)

Procurement Guide and Technical Reference Standards

Procurement Reference Standards

When purchasing these BOP parts, please refer to the following standards to ensure product quality, compatibility, and compliance with safety requirements: 1. API Spec 16A (Fourth Edition) international standard for BOP parts; 2. GB/T 20174-2019 national standard for well control equipment; 3. OEM dimension standards for FZ35-70, 2FZ35-70, and RS11819 Ram BOPs; 4. ISO 9001:2015 quality management system certification requirements; 5. API 16A Monogram certification requirements. We provide a complete set of quality inspection reports, API 16A certification documents, dimensional drawings, and non-destructive testing reports for each batch of parts, ensuring that the products meet the above standards. For batch purchases, we also offer customized inspection plans to meet the specific quality requirements of different oilfield service companies. When purchasing, please confirm the BOP model and part model to avoid mismatches—you can provide the BOP’s serial number for our technical team to verify compatibility.

Technical Problem Reference Standards

For common technical problems (such as rectangular gasket leakage, piston rod jamming, shear ram seal wear, fastener breakage), please refer to the following solutions, in line with API 16AR maintenance guidelines and industry best practices: 1. Rectangular gasket leakage: Replace the gasket with our RSU816.28 model, clean the sealing surface, and apply anti-corrosion lubricant; 2. Piston rod jamming: Replace the piston rod with our RSU818.08 or RSU818.07 model, clean the cylinder bore, and apply high-temperature lubricant; 3. Shear ram seal wear: Replace the seal with our K511X16.07.10.03 model, adjust the shear ram position, and conduct a pressure test; 4. Fastener breakage: Replace the fastener with our high-strength model (such as RS11816.31 Shaft connecting bolt), retighten with specified torque. Our technical team provides 24/7 online support to help you solve on-site technical problems quickly, and can send senior engineers to the site for guidance if necessary, ensuring minimal downtime.

Procurement Guidance

If you are in need of RSU816.28 Rectangular Gasket FZ35-70 Ram BOP, RSU818.08 Open Piston Rod, K511X16.07.10.03 Shear Ram Side Seal II, or other listed parts for FZ35-70, 2FZ35-70, and RS11819 Ram BOPs, please contact us directly. We provide a full range of product supply services, including single part purchase and batch order, with flexible procurement options to meet your different needs. All products are 100% factory-tested, with reliable quality and stable performance, meeting API Spec 16A and GB/T 20174 standards, and ensuring the safety of your BOP operations. We can provide detailed product specifications, dimension drawings, API certification documents, and non-destructive testing reports to help you make the right procurement decision. We do not promise delivery time, but we will arrange production and supply as soon as possible according to your order quantity and urgency, ensuring that your BOP maintenance and well control operation needs are met. In addition, we provide a one-year quality guarantee for all parts—if there is any quality problem within the guarantee period, we will replace the parts free of charge, helping you reduce operational risks and maintenance costs. Whether you need a single replacement part or a batch of spare parts for your BOP fleet, we have the expertise and supply capacity to meet your requirements.

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