Reliable BOP Control Unit for Blowout Preventer Systems – API Standard Compliant

Description

Goldenman API 16D BOP Control Unit is a high-pressure hydraulic control system designed to operate blowout preventers, choke and kill outlet valves and other specified well-control functions on land-based and surface-mounted BOP stacks.

The standard reference configuration operates at 3,000 psi / 207 bar and uses six 11-gallon accumulator bottles. Hydraulic reservoir capacities from 250 to 600 liters are available, together with pneumatic, electric or diesel-driven pump options.

Local hydraulic control is provided as standard according to the approved function arrangement. Remote control panels, additional accumulator banks, redundant pump packages, trailer mounting and project-specific alarm or monitoring systems can be configured according to the drilling rig and well-control program.

The final control unit is engineered from the actual BOP stack function list, operator volumes, required operating pressures, emergency sequence and available rig utilities—not from accumulator bottle quantity alone.

Product Short Description

The Goldenman BOP Control Unit stores and delivers high-pressure hydraulic fluid for rapid operation of Annular BOPs, Ram BOPs and hydraulically operated well-control valves.

Its modular design supports different accumulator capacities, pump combinations, control functions and remote operating stations. Each system is configured according to the required BOP operating volumes, control pressure, function sequence, environmental conditions and inspection requirements.

Product Highlights

• Designed for API 16D land-based and surface-mounted BOP control applications
• Rated system pressure of 3,000 psi / 207 bar
• Standard reference configuration with 6 × 11 gal accumulator bottles
• Hydraulic reservoir options from 250 to 600 L
• Pneumatic, electric or diesel-driven pump options
• Local manual hydraulic control manifold
• Optional remote driller’s control panel
• Skid-mounted or trailer-mounted construction
• Configurable number of BOP and valve functions
• Separate Annular BOP pressure regulation available
• Pressure gauges, regulators and relief protection
• Low-temperature and hazardous-area configurations
• Stainless-steel tubing and corrosion-resistant component options
• Accumulator sizing calculation according to the actual BOP stack
• Functional testing, drawdown testing and documentation support
• Recommended spare-parts packages available

What Is a BOP Control Unit?

A BOP Control Unit is the hydraulic power and control system used to open, close and regulate drilling well-control equipment.

The system stores pressurized hydraulic fluid in accumulator bottles. When an operator selects a function, control valves direct the stored fluid to the appropriate BOP operator or hydraulic valve actuator.

A complete surface BOP control unit normally includes:

• Hydraulic fluid reservoir
• Accumulator bottles
• Air, electric or diesel-driven pumps
• Hydraulic control manifold
• Pressure regulators
• Relief valves
• Isolation valves
• Pressure gauges
• Check valves
• Hydraulic tubing and fittings
• Local control handles
• Remote control interfaces
• Instrumentation and alarm components
• Skid or trailer structure

The system must remain capable of performing its required well-control functions when normal rig power is interrupted, subject to the approved accumulator capacity and operating sequence.

Main Controlled Functions

The BOP control unit can be configured to operate:

• Annular Blowout Preventer
• Upper pipe ram
• Lower pipe ram
• Variable-bore ram
• Blind ram
• Shear ram
• Blind shear ram
• Hydraulic ram locks
• Choke-line outlet valve
• Kill-line outlet valve
• Hydraulic drilling spool valves
• Hydraulic wellhead connector
• Diverter equipment when included in the approved system
• Other specified well-control functions

Each controlled function requires its own valve arrangement, identification, hydraulic piping and operating-volume allowance.

The number of functions should therefore be defined from the BOP stack schematic rather than using a general description such as “suitable for single, double and Annular BOPs.”

General Technical Specifications

Parameter	Available Specification
Product name	BOP Control Unit
Applicable standard	API Spec 16D, applicable current edition
API product scope	Control System for Land-Based and Surface-Mounted BOP Stacks
Rated system pressure	3,000 psi / 207 bar
Standard accumulator configuration	6 × 11 gal bottles
Accumulator arrangement	Project-specific, based on sizing calculation
Hydraulic reservoir	250–600 L
Pump options	Pneumatic, electric or diesel-driven
Combined pump package	Available according to redundancy requirements
Local operation	Hydraulic control manifold
Remote control	Optional remote panel
Mounting type	Skid-mounted or trailer-mounted
Number of functions	According to the approved BOP function matrix
Annular pressure control	Adjustable regulator configuration available
Ram and valve control	According to required operating pressure
Operating temperature	−20°C to +55°C reference range
Low-temperature design	Available according to project conditions
Hydraulic fluid	Project-specified control fluid
Electrical classification	According to installation area
Tubing and fittings	Carbon steel or stainless steel as specified
Certification	Applicable API certificate
Inspection	Factory and third-party inspection as specified

The final accumulator quantity, pump capacity, reservoir volume, number of functions and control-panel arrangement must be confirmed through an approved hydraulic schematic and sizing calculation.

Standard Reference Configuration

The existing Goldenman page presents the following sample system:

Component	Reference Configuration
System pressure	3,000 psi / 207 bar
Accumulator bottles	6 units
Individual bottle size	11 gal
Reservoir capacity	250–600 L
Pump drive	Pneumatic, electric or diesel
Local control	Manual hydraulic control
Remote control	Optional
Installation	Skid or trailer
Temperature range	−20°C to +55°C

This is a reference configuration rather than a universal specification.

Two systems with six 11-gallon accumulator bottles may have different usable-fluid capacities because of differences in:

• Nitrogen precharge pressure
• Pump start pressure
• Pump stop pressure
• Minimum required operating pressure
• Ambient temperature
• Bottle isolation arrangement
• Hydraulic losses
• Required operating sequence

Why Accumulator Bottle Count Is Not Enough

The nominal volume stamped on an accumulator bottle is the internal vessel volume. It is not the same as the volume of pressurized hydraulic fluid available to operate the BOP stack.

Usable fluid volume depends on:

• Accumulator precharge pressure
• Maximum system pressure
• Pump start pressure
• Minimum acceptable manifold pressure
• Ambient and fluid temperature
• Required BOP operating pressure
• Number of bottles available after isolation
• System pressure losses
• Emergency operating sequence

For this reason, a statement such as “6 × 11 gal” cannot by itself confirm that the system is large enough.

The engineering review must compare the available usable fluid with the volume and pressure required to perform the specified well-control functions.

Accumulator Sizing Inputs

The following information is required for accurate sizing:

BOP Operator Volumes

Provide opening and closing volumes for:

• Each Annular BOP
• Each Ram BOP cavity
• Blind or shear rams
• Hydraulic ram locks
• Choke valves
• Kill valves
• Hydraulic connectors
• Diverter functions, when applicable

Required Operating Pressures

Provide:

• Normal control manifold pressure
• Annular BOP closing pressure
• Pipe ram closing pressure
• Shear ram required pressure
• Choke and kill valve actuator pressure
• Maximum operator pressure
• Minimum acceptable pressure after operation

Required Function Sequence

The project must define the emergency or drawdown sequence, which may include:

1. Closing the Annular BOP with the largest operator volume
2. Closing and sealing a pipe ram
3. Operating the specified shear function where required
4. Closing choke or kill outlet valves
5. Performing an emergency sequence defined by the project

The sequence must be based on the actual BOP stack and approved well-control philosophy.

Reserve and Redundancy

The sizing review should also consider:

• Loss of one accumulator bottle or bank
• Pump failure
• Loss of primary rig power
• Required emergency reserve
• Additional remote-panel functions
• Hydraulic leakage allowance
• Future BOP stack expansion

Selecting the Correct Number of Control Functions

Every hydraulic operation must be counted as a defined control function.

For example, a surface BOP stack may require separate controls for:

• Annular BOP open and close
• Upper pipe ram open and close
• Lower pipe ram open and close
• Blind shear ram open and close
• Ram locks
• Choke valve open and close
• Kill valve open and close
• Hydraulic connector
• Diverter packer
• Diverter line valves

The quotation should state:

• Total number of control functions
• Function names
• Normal drilling position
• Fail-safe position where applicable
• Required regulator pressure
• Local control requirement
• Remote control requirement
• Position-indication requirement

A control unit with the correct accumulator capacity can still be unsuitable if it does not contain enough valves or correctly arranged functions.

Pump System Options

Pneumatic Pump System

An air-powered pump is suitable when the drilling rig has a reliable compressed-air supply.

Advantages can include:

• No electric motor at the pump
• Suitability for many hazardous-area installations
• Simple speed control
• Automatic pressure maintenance
• Easy integration with rig air systems

The buyer should provide:

• Available air pressure
• Available airflow
• Air quality
• Minimum ambient temperature
• Required recharge time

Insufficient air volume can prevent the pump from restoring system pressure at the required rate.

Electric Motor-Driven Pump

An electric pump provides continuous hydraulic recharge from the rig electrical system.

Selection requires:

• Supply voltage
• Frequency
• Phase
• Motor power
• Hazardous-area classification
• Enclosure and protection level
• Cable-entry requirements
• Starting method

The electrical pump may be combined with an air-powered backup pump when redundancy is required.

Diesel Engine-Driven Pump

A diesel-driven pump can provide an independent power source where rig electricity or compressed air is unavailable or unreliable.

The design review should include:

• Engine power
• Fuel-tank capacity
• Starting system
• Battery arrangement
• Exhaust routing
• Fire protection
• Cold-start requirements
• Installation ventilation
• Noise and maintenance access

A diesel system may be installed on a trailer or separate skid according to the project layout.

Local Hydraulic Control Manifold

The local manifold allows operators to control and monitor BOP functions directly from the accumulator unit.

The manifold can include:

• Function control valves
• Annular BOP pressure regulator
• Main manifold regulator
• System pressure gauge
• Accumulator pressure gauge
• Annular pressure gauge
• Air-supply pressure gauge
• Pump isolation valves
• Relief valves
• Bleed and drain valves
• Function labels
• Graphic representation of the BOP stack

Function names and valve orientation should match the approved BOP schematic and remote control panel.

Remote Control Panel

An optional remote panel allows the driller or well-control operator to operate selected functions from a safer location.

The panel configuration can include:

• Graphic BOP stack layout
• Open and close controls
• Function-status indication
• Accumulator pressure display
• Manifold pressure display
• Annular pressure display
• Low-pressure alarms
• Pump fault indication
• Emergency function protection
• Two-action controls for critical functions
• Pneumatic, electric or electro-hydraulic communication

The remote panel should duplicate the correct function names and flow-path arrangement of the local control manifold.

Critical functions such as shear-ram closure should be protected against unintended operation according to the approved control philosophy.

Annular BOP Pressure Regulation

An Annular BOP normally requires adjustable closing pressure because the required hydraulic pressure changes with:

• Wellbore pressure
• Tubular outside diameter
• Packing-element condition
• Stripping operation
• Elastomer characteristics
• Required sealing force

Applying unnecessarily high closing pressure can accelerate packing-element wear and increase contact force on the tubular.

The control unit can therefore be configured with a separate Annular BOP regulator and pressure indication.

Ram BOP and Shear Function Requirements

Pipe, blind and shear ram functions may have different operating-pressure requirements.

For a shear ram, the control-system review must consider:

• Tubular outside diameter
• Wall thickness
• Steel grade
• Tool-joint position
• Required shearing force
• BOP closing ratio
• Maximum operator pressure
• Hydraulic line restrictions
• Available accumulator pressure

A standard 3,000 psi manifold does not automatically confirm that a specific shear ram can cut every tubular in the drilling program.

The BOP manufacturer’s required operator pressure and verified shear data must be used.

Can a 3,000 psi Control Unit Operate a 10,000 or 15,000 psi BOP?

The BOP wellbore pressure rating and its hydraulic operating pressure are different specifications.

A BOP may be rated to contain 10,000 or 15,000 psi wellbore pressure while using a much lower hydraulic control pressure to operate its piston or ram mechanism.

Compatibility depends on:

• Required BOP operator pressure
• Operator opening and closing volume
• Closing ratio
• Wellbore pressure during operation
• Hydraulic locking system
• Shear requirement
• Control-line pressure loss

The BOP datasheet must therefore be reviewed rather than matching the control unit pressure directly to the BOP wellbore rating.

Skid-Mounted and Trailer-Mounted Designs

Skid-Mounted BOP Control Unit

A skid-mounted system is suitable for:

• Permanent or semi-permanent rig installation
• Integration into a rig equipment package
• Fixed hydraulic line routing
• Offshore platform installations
• Installations with dedicated handling equipment

Trailer-Mounted BOP Control Unit

A trailer-mounted system may be preferred for:

• Mobile land rigs
• Workover operations
• Rental equipment fleets
• Movement between well sites
• Independent diesel-driven packages
• Rapid field deployment

The trailer design should account for transport dimensions, axle loading, brakes, towing requirements, lighting and local road regulations.

Environmental and Hazardous-Area Requirements

The buyer should define:

• Minimum ambient temperature
• Maximum ambient temperature
• Marine or land environment
• Dust and moisture exposure
• Salt-spray conditions
• Hazardous-area classification
• Electrical certification
• Required enclosure rating
• Heating or insulation requirements
• Sunshade or protective housing
• Arctic or desert operation

For low-temperature projects, the review should cover:

• Hydraulic fluid viscosity
• Pump starting performance
• Accumulator precharge
• Elastomer compatibility
• Instrument accuracy
• Reservoir heating
• Condensation and freezing protection

Replacement Control Unit Compatibility

A replacement BOP control unit should not be ordered using only its pressure and accumulator quantity.

Provide:

• Existing manufacturer and model
• System working pressure
• Accumulator bottle quantity and size
• Precharge pressure
• Pump start and stop pressure
• Reservoir capacity
• Pump type and capacity
• Number of functions
• Function names
• Annular regulator requirement
• Existing BOP operator volumes
• Remote panel configuration
• Electrical supply
• Air-supply data
• Hydraulic line connections
• Overall dimensions
• Existing hydraulic schematic
• Hazardous-area classification

Goldenman will review the existing system and prepare a replacement function matrix, sizing calculation and hydraulic drawing.

Manufacturing and Quality Control

Goldenman quality-control activities can include:

• Accumulator bottle certificate verification
• Pressure-vessel documentation review
• Hydraulic component inspection
• Pump performance verification
• Reservoir dimensional inspection
• Tubing cleanliness inspection
• Tube and fitting pressure-rating verification
• Hydraulic manifold assembly inspection
• Relief-valve setting verification
• Regulator function testing
• Pressure-gauge calibration review
• Electrical component inspection
• Remote panel functional verification
• Skid or trailer dimensional inspection
• Coating and preservation inspection
• Product marking verification
• Final documentation review

The final quality and inspection plan is established according to the API scope, approved drawings and purchase requirements.

Factory Acceptance Test

The agreed FAT can include:

• Approved drawing review
• Hydraulic schematic verification
• Function-matrix verification
• Accumulator precharge inspection
• Pump start and stop pressure test
• Pump capacity test
• Pressure-holding and leakage test
• Regulator adjustment test
• Relief-valve function test
• Local valve function test
• Remote panel function test
• Function-status indication test
• Alarm and fault simulation
• Accumulator drawdown test
• BOP simulator or load test
• Emergency pump test
• Electrical continuity and insulation checks
• Product marking inspection
• Coating inspection
• Documentation review

The test procedure, acceptance criteria and customer witness points should be agreed before production.

Available Documentation

The project documentation package can include:

• API certificate
• Certificate of Conformity
• Approved product datasheet
• General arrangement drawing
• Hydraulic schematic
• Piping and instrumentation diagram
• BOP control function matrix
• Accumulator sizing calculation
• Pump sizing calculation
• Reservoir sizing information
• Accumulator bottle certificates
• Material certificates where applicable
• Pressure-gauge calibration certificates
• Relief-valve setting certificates
• Pressure and leakage test report
• Pump performance test report
• Drawdown test report
• Local and remote functional test report
• Electrical drawings
• Hazardous-area component certificates
• Operation and maintenance manual
• Recommended spare-parts list
• Packing list
• Third-party inspection report

Recommended Spare Parts

A project-specific spare-parts package may include:

• Pressure regulators
• Function control valves
• Relief-valve kits
• Check valves
• Pump seal kits
• Air-pump repair kits
• Electric-pump components
• Pressure gauges
• Pressure switches
• Accumulator bladder or internal repair parts
• Hydraulic tubing and fittings
• Filter elements
• Remote-panel valves
• Indicator lamps and switches
• Hydraulic hose assemblies
• Seals and O-rings

Spare quantities should reflect the number of wells, operating period and availability of local technical support.

Frequently Asked Questions

Is six 11-gallon accumulator bottles enough for every BOP stack?

No.

The correct capacity depends on the opening and closing volumes of every BOP and hydraulic valve, the required operation sequence, precharge pressure, pump-start pressure and minimum acceptable system pressure.

A six-bottle configuration is a reference arrangement and must be verified through an accumulator sizing calculation.

What is the difference between nominal accumulator volume and usable fluid volume?

Nominal volume is the internal capacity of the accumulator vessel.

Usable fluid volume is the amount of pressurized hydraulic fluid that can be discharged between the defined starting pressure and minimum required operating pressure. It is normally much lower than the total nominal bottle volume.

What BOP data are required to size the control unit?

Provide the opening and closing volumes, required operating pressures and function names for:

• Annular BOPs
• Ram BOPs
• Blind or shear rams
• Ram locks
• Choke valves
• Kill valves
• Hydraulic connectors
• Diverter functions

The required emergency operating sequence must also be defined.

Can this unit control both Annular and Ram BOPs?

Yes, when the control manifold contains the required functions and the accumulator system has sufficient usable fluid.

The Annular BOP normally requires an adjustable pressure regulator, while Ram BOP functions are configured according to their required operator pressure.

How should pneumatic, electric and diesel pumps be selected?

The selection depends on available rig utilities and the required redundancy.

Pneumatic pumps require adequate compressed-air pressure and flow. Electric pumps require the correct voltage and hazardous-area classification. Diesel-driven pumps provide an independent power source but require fuel, ventilation and starting-system provisions.

Can the BOP control unit operate a shear ram?

Yes, when the system can provide the pressure and volume required by the specific shear ram and tubular program.

The review must use verified shear data, including pipe size, wall thickness, grade and required operator pressure.

Can a 3,000 psi control unit operate a 15,000 psi Ram BOP?

Possibly, because the 15,000 psi rating refers to wellbore pressure containment, while 3,000 psi refers to hydraulic control pressure.

Compatibility must be confirmed using the BOP operator pressure, closing ratio, wellbore pressure and required fluid volume.

Can the system be expanded with more control functions later?

Expansion may be possible when the manifold, accumulator capacity, pump capacity, reservoir and remote panel have sufficient allowance.

Future functions should be considered during the original design because adding control valves alone may leave the accumulator system undersized.

What should be checked when replacing an existing BOP closing unit?

Check the complete function matrix, operator volumes, accumulator usable capacity, pump capacity, control pressures, hydraulic interfaces and remote-panel logic.

The same bottle quantity does not guarantee equivalent performance.

What should be included in the BOP Control Unit FAT?

The FAT should normally verify pump operation, pressure regulation, relief-valve settings, leakage, local and remote functions, alarms, accumulator drawdown and the approved function sequence.

Project-specific witness and hold points should be agreed before manufacturing.

Is this control unit suitable for a subsea BOP stack?

This page covers control systems for land-based and surface-mounted BOP stacks.

Discrete hydraulic, electro-hydraulic/MUX and secondary control systems for subsea BOP stacks are separate API 16D product categories and require different system architecture, redundancy and qualification.

Information Required for Quotation

Please provide:

• Land rig or surface-mounted offshore application
• BOP stack schematic
• Number of Annular BOPs
• Annular opening and closing volumes
• Number and type of Ram BOPs
• Ram opening and closing volumes
• Blind or shear ram requirements
• Required shear-ram operating pressure
• Choke and kill valve functions
• Hydraulic connector functions
• Diverter functions, when applicable
• Total number of control functions
• Required emergency operation sequence
• Required system pressure
• Accumulator precharge requirement
• Required accumulator reserve
• Preferred pump type
• Available air pressure and airflow
• Electrical voltage, frequency and phase
• Hazardous-area classification
• Reservoir capacity preference
• Local and remote control requirements
• Alarm and monitoring requirements
• Skid or trailer mounting
• Minimum and maximum ambient temperature
• API certificate requirements
• FAT and third-party inspection requirements
• Required documentation
• Destination country
• Delivery schedule

For replacement systems, also provide the existing nameplate, hydraulic schematic, function list, accumulator configuration and equipment photographs.

Request a Technical Quotation

Goldenman supplies API 16D BOP Control Units for land rigs, workover rigs and surface-mounted BOP stacks.

Available configurations include pneumatic, electric and diesel-driven pump systems, 250–600 L reservoirs, project-specific accumulator banks, local hydraulic manifolds and remote control stations.

Send your BOP stack schematic, function list, operator volumes, required pressures and rig utility information to:

Email: info@goldenman.com

Goldenman will review the operating sequence and prepare the accumulator sizing calculation, hydraulic schematic, technical datasheet and commercial quotation.