Description
API 16D BOP Control Unit for Surface Well Control
SGPE supplies API 16D BOP Control Units for the hydraulic operation of surface blowout preventers, diverter systems and related well control equipment.
The system stores pressurized control fluid in a nitrogen-precharged accumulator bank. When the driller selects a function, the hydraulic control manifold directs the stored fluid to the correct opening or closing circuit. As a result, the BOP stack can respond immediately without waiting for the charging pumps to build pressure from zero.
A complete hydraulic BOP control system can operate annular BOPs, fixed-bore pipe rams, variable bore rams, blind rams, blind shear rams, casing shear rams, choke line HCR valves, kill line HCR valves and other hydraulically actuated well control equipment.
Oilfield crews may also refer to this equipment as a BOP accumulator unit, BOP closing unit, Koomey unit, blowout preventer control system or BOP hydraulic power unit.
Available control architectures include pneumatic FKQ control units, electro-pneumatic FKDQ systems and electric or PLC-controlled FKD systems. In addition, buyers can choose an open-skid package, weatherproof unit, insulated shelter or fully containerized BOP control house.
Each package is engineered around the installed BOP stack. Therefore, operator displacement, function sequence, recharge time, control distance, available utilities and environmental conditions all influence accumulator capacity, pump output and control layout.
BOP Accumulator Unit at a Glance
| Selection Item | Typical Configuration |
|---|---|
| Product Type | BOP control unit, accumulator unit or hydraulic closing unit |
| Design Basis | Project requirements based on API Spec 16D |
| Main Hydraulic Pressure | Commonly 21 MPa / 3,000 psi |
| Optional High-Pressure Circuit | Up to 34.5 MPa / 5,000 psi after engineering review |
| Controlled Functions | 3 to 12 or more |
| Control Architecture | Pneumatic, electro-pneumatic, electric or PLC |
| Charging Sources | Electric pump, air-driven pump or redundant combination |
| Nominal Accumulator Capacity | Approximately 240 to 3,400 L, including custom systems |
| Remote Operation | Driller panel, auxiliary panel or emergency station |
| Installation | Open skid, weatherproof skid or containerized control house |
| Applications | Land drilling, offshore surface BOP systems and selected workover projects |
| Documentation | Drawings, calculations, test reports and operation manuals |
These values describe the general supply range. Final parameters follow the approved BOP stack, hydraulic calculation and project specification.
How a Hydraulic BOP Control System Works
The charging pumps draw approved control fluid from the reservoir and deliver it to nitrogen-precharged accumulator bottles. As fluid enters each bottle, it compresses the nitrogen and stores hydraulic energy.
When the driller selects a function, the control manifold sends the stored fluid into the required hydraulic circuit. The selected annular BOP, ram preventer, shear ram or HCR valve then opens or closes.
After the movement finishes, return fluid flows back to the reservoir. Meanwhile, the electric pump, air-driven pump or combined charging package restores the accumulator bank to the preset pressure.
Pressure switches control the normal pump start and stop points. Regulators reduce the main system pressure when a function needs a lower operating pressure. The annular BOP, for example, normally operates through an adjustable regulated circuit.
Check valves prevent reverse flow from the accumulator bank, while relief valves protect the hydraulic circuit from excessive pressure. Isolation valves also allow technicians to separate selected components during inspection or maintenance.
Because the accumulator bank stores energy in advance, the rig crew has immediate access to hydraulic power during routine operation, BOP testing and well control response.
Project-Specific BOP Accumulator Sizing
A BOP closing unit should not be selected only by rig size, bottle quantity or reference model.
Correct sizing starts with the opening and closing displacement of every hydraulic operator. Therefore, the engineering review should cover:
- annular BOP operators;
- fixed-bore and variable bore ram operators;
- blind and shear ram operators;
- choke and kill line HCR valves;
- diverter functions;
- hydraulic connectors;
- other project-specific hydraulic valves.
The calculation must also consider the required operating sequence, nitrogen precharge, maximum charging pressure, minimum final operating pressure, ambient temperature and allowable recharge time.
Nominal accumulator capacity does not equal usable hydraulic volume. For example, two systems with the same total bottle capacity may deliver different usable volumes because they use different precharge pressures, final operating pressures, temperatures or bank arrangements.
Consequently, the hydraulic review determines the required bottle quantity, accumulator bank arrangement, pump capacity and minimum reservoir volume.
Where required, the bottles can be divided into several isolated banks. This arrangement supports maintenance and can improve operational flexibility.
Key Features of the BOP Control Unit
Electric and Air-Driven Charging Pumps
A typical BOP accumulator unit combines an electric charging pump with one or more air-driven pumps.
The electric pump handles routine charging. However, if the rig loses electrical power, the pneumatic pump can continue charging the system as long as an adequate compressed-air supply remains available.
Large BOP stacks may need multiple pumps or a higher combined flow rate. Pump quantity and output therefore depend on accumulator capacity, target recharge time and the required level of redundancy.
Local and Remote BOP Operation
The main hydraulic manifold provides direct local control. At the same time, a driller control panel places the principal BOP functions near the drilling control position.
Auxiliary and emergency stations can provide additional operating locations. Depending on the project, remote commands may use pneumatic signals, electrical controls, solenoid valves, electro-pneumatic components or PLC logic.
The selected control method should match the rig layout, control distance, climate and available utilities.
Control Layout Matched to the BOP Stack
The manifold and remote panels can follow the actual BOP stack arrangement instead of relying only on generic valve numbers.
Clear labels and stack graphics help operators identify the annular BOP, upper ram, lower ram, shear ram, choke line valve and kill line valve.
As a result, the layout simplifies routine function testing and reduces the chance of selecting the wrong hydraulic circuit.
Pressure, Alarm and Status Monitoring
The system can monitor accumulator pressure, manifold pressure, annular pressure, reservoir level, pump condition, electrical supply and compressed-air supply.
Monitoring options include pressure gauges, pressure switches, pilot lights, audible alarms, digital displays and PLC-based status pages.
Where the project requires traceability, a data logging system can record pressure conditions, alarm events and operating commands.
Protection for Harsh Oilfield Environments
The package can be adapted for offshore, desert, tropical and low-temperature service.
Available features include:
- marine-grade coating;
- stainless-steel hydraulic tubing;
- sealed electrical enclosures;
- dust protection;
- sunshades;
- forced ventilation;
- air conditioning;
- insulated control houses;
- space heaters;
- hydraulic tank heaters;
- heat-traced control lines;
- low-temperature seals.
The final environmental package follows the ambient temperature, humidity, dust level, salt exposure and hazardous-area requirements.
Typical BOP Control Functions
| Controlled Equipment | Hydraulic Operation | Main Selection Data |
| Annular BOP | Open, close and regulate closing pressure | Operator volume and regulated pressure |
| Upper Pipe Ram | Open and close around the specified tubular | Opening and closing volume |
| Lower Pipe Ram | Open and close around the specified tubular | Opening and closing volume |
| Variable Bore Ram | Seal around an approved tubular size range | Ram model and operator volume |
| Blind Ram | Close and seal an open wellbore | Operator volume and control pressure |
| Blind Shear Ram | Shear the specified tubular and seal the wellbore | Tubular data and required shear pressure |
| Casing Shear Ram | Shear casing or heavy tubulars | Casing size, grade, weight and operator data |
| Choke Line HCR Valve | Open and close the choke line valve | Actuator volume and fail position |
| Kill Line HCR Valve | Open and close the kill line valve | Actuator volume and fail position |
| Diverter Element | Open and close the sealing element | Operator volume and closing pressure |
| Diverter Flow-Line Valve | Direct flow to the selected discharge line | Actuator volume and operating sequence |
| Hydraulic Connector | Lock or unlock the connector | Lock and unlock volumes |
| Additional Hydraulic Valve | Operate a project-specific function | Actuator type, volume and pressure |
Main Components of the BOP Accumulator Unit
| Main Component | Function | Typical Configuration |
| Accumulator Bottle Bank | Stores hydraulic energy | Bladder-type bottles with dry nitrogen precharge |
| Hydraulic Fluid Reservoir | Stores and receives control fluid | Level indication, filtration and drain connections |
| Electric Pump Package | Provides normal charging | One or more motor-driven pumps |
| Air-Driven Pump Package | Provides independent backup charging | One or more pneumatic pumps |
| Hydraulic Control Manifold | Directs fluid to each function | Directional valves, regulators and gauges |
| Annular Pressure Regulator | Reduces pressure to the annular BOP | Manual, pneumatic, electric or PLC adjustment |
| Driller Control Panel | Provides remote operation | Pneumatic, electro-pneumatic, electric or touchscreen |
| Auxiliary Control Station | Adds another operating point | Project-specific function arrangement |
| Alarm System | Monitors pressure, level and utilities | Audible, visual or PLC-based alarms |
| Hydraulic Hoses and Tubing | Connects the unit to the BOP stack | Rigid tubing, hose bundles or individual hoses |
Accumulator Bottle Bank
The accumulator bank stores hydraulic energy for routine and emergency BOP operation.
Standard packages commonly use bladder-type bottles with dry nitrogen precharge. Bottle quantity and bank arrangement follow the approved hydraulic calculation.
Where practical, isolation valves divide the bottles into separate groups. Technicians can then isolate one bottle or bank without unnecessarily disabling the complete system.
Hydraulic Fluid Reservoir
The reservoir supplies fluid to the charging pumps and receives return flow from the controlled equipment.
Its capacity must allow for operator demand, return volume, thermal expansion and maintenance. Typical accessories include a level indicator, inspection cover, drain connection, suction strainer and return filter.
Optional equipment includes a low-level switch, filling connection, sampling point, temperature sensor and hydraulic tank heater.
The project may specify petroleum-based hydraulic oil, water-glycol fluid or another approved control medium. Accordingly, seals, filters and reservoir materials must match the selected fluid and operating temperature.
Charging Pump Packages
The electric pump charges the accumulator bank and maintains system pressure. Automatic pressure switches control the normal start and stop points.
Meanwhile, the air-driven pump provides an independent charging source. Its air preparation assembly normally includes an isolation valve, filter, regulator, lubricator, gauge and low-air-pressure switch.
The final pump arrangement depends on accumulator capacity, available utilities, recharge time and redundancy requirements.
Hydraulic Control Manifold
The main manifold distributes control fluid to each BOP function.
A typical arrangement includes directional valves, pressure regulators, gauges, isolation valves, check valves, relief valves and clearly identified outlets.
The valve layout can follow the approved BOP stack sequence. As a result, operation, function testing and troubleshooting become easier for the rig crew.
Annular BOP Pressure Regulator
The annular regulator reduces the main system pressure to the level required by the annular operator.
This allows the drilling crew to control closing force when sealing around drill pipe, casing, tubing or another tubular.
Pressure adjustment may be manual, pneumatic, air-motor, electric or PLC-controlled. However, the selected range must remain within the annular BOP manufacturer’s operating limits.
Driller, Auxiliary and Emergency Control Panels
The driller panel provides remote operation of selected well control functions.
Depending on the configuration, it can display accumulator pressure, manifold pressure, annular pressure, air pressure, pump condition, alarm status and function position.
Auxiliary and emergency stations provide additional operating locations. Critical commands, including shear ram closure, may use guarded switches, lockable covers or two-action controls.
BOP Control Hoses and Hydraulic Piping
The accumulator unit connects to the BOP stack through rigid tubing, bundled hoses or individual high-pressure hydraulic hose assemblies.
The connection package may include stainless-steel tubing, hose reels, hose racks, junction boxes, bulkhead fittings, pipe clamps and tagged hose assemblies.
Hose size, pressure rating, connection type, total length and routing follow the final rig layout. Clear identification also helps simplify installation, testing and future maintenance.
FKQ, FKDQ and FKD Control System Comparison
| Control System | Main Control Method | Main Advantages | Typical Application |
| FKQ Pneumatic Control Unit | Pneumatic signals operate the main manifold | Familiar operation and straightforward layout | Conventional land drilling and workover rigs |
| FKDQ Electro-Pneumatic Unit | Electrical commands activate pneumatic or hydraulic controls | Longer control distance and improved monitoring | Modern land rigs and offshore surface installations |
| FKD Electric Control System | Electrical controls and solenoid valves operate the functions | Reduced dependence on pneumatic signal lines | Automated rigs and low-temperature projects |
| PLC-Controlled System | PLC logic manages commands, alarms and status | Data recording and integrated monitoring | Advanced drilling packages |
| Local Hydraulic Closing Unit | Functions operate at the main manifold | Compact arrangement and direct control | Workover and well servicing packages |
The correct architecture depends on control distance, climate, rig layout, available utilities, hazardous-area requirements and desired automation level.
Installation Options
| Installation Type | Main Features | Suitable Environment |
| Open-Skid Unit | Direct access to pumps, manifold and bottles | Standard land drilling locations |
| Weatherproof Skid | Protective covers or partial enclosure | Exposed land rig installations |
| Containerized Control Unit | Fully enclosed and protected package | Offshore, desert and cold-region projects |
| Insulated Control House | Thermal insulation and heating | Low-temperature drilling |
| Offshore Package | Marine coating and corrosion-resistant tubing | Fixed platforms, jack-ups and drilling barges |
| Mobile Workover Unit | Compact frame and reduced transport weight | Mobile workover and well servicing rigs |
Workover, completion and well servicing packages must follow the applicable equipment standard and end-user specification.
Operating a BOP alone does not make a hydraulic closing unit compliant with API Spec 16D. In addition, subsea BOP control systems use a different architecture and require a separate engineering review.
Typical Technical Specifications
| Parameter | Typical Configuration |
| Product Name | API 16D BOP Control Unit |
| Alternative Names | BOP Accumulator Unit, BOP Closing Unit, Koomey Unit |
| Main Function | Hydraulic control of surface BOP and diverter equipment |
| Design Basis | Project requirements based on API Spec 16D |
| Main System Pressure | Commonly 21 MPa / 3,000 psi |
| Optional High-Pressure Circuit | Up to 34.5 MPa / 5,000 psi after engineering review |
| Annular Control Pressure | Adjustable according to the annular operator |
| Accumulator Precharge | Defined by the approved hydraulic calculation |
| Controlled Functions | 3 to 12 or more |
| Nominal Accumulator Capacity | Approximately 240 to 3,400 L, including custom systems |
| Hydraulic Reservoir Capacity | Approximately 560 to 4,500 L |
| Electric Pump Quantity | One or more |
| Air-Driven Pump Quantity | One or more |
| Electric Motor Power | Approximately 11 to 90 kW |
| Available Voltage | 380, 400, 415, 440 or 460 V; custom voltage available |
| Frequency | 50 or 60 Hz |
| Compressed-Air Supply | Commonly approximately 0.65 to 0.8 MPa |
| Control Fluid | Approved hydraulic oil or water-glycol fluid |
| Control Method | Hydraulic, pneumatic, electro-pneumatic, electric or PLC |
| Installation | Open skid, weatherproof skid or containerized unit |
| Environmental Protection | Heating, cooling, insulation, dust and corrosion protection |
| Electrical Protection | Industrial or explosion-protected configuration |
| Alarm Functions | Pressure, level, pump, power, air supply and temperature alarms |
| Inspection | Manufacturer inspection or agreed third-party witnessing |
The 5,000 psi option normally applies to a dedicated shear or another project-specific circuit. It does not mean that every component in the complete control system operates at 5,000 psi.
Final pressure ratings, materials and certification requirements follow the approved project specification.
Common FKQ BOP Control Unit Models
| Reference Model | Nominal Accumulator Capacity | Controlled Functions | Common Main Pressure |
| FKQ240-3 | 240 L | 3 | 3,000 psi |
| FKQ320-4 | 320 L | 4 | 3,000 psi |
| FKQ320-5 | 320 L | 5 | 3,000 psi |
| FKQ400-5 | 400 L | 5 | 3,000 psi |
| FKQ400-6 | 400 L | 6 | 3,000 psi |
| FKQ480-5 | 480 L | 5 | 3,000 psi |
| FKQ480-6 | 480 L | 6 | 3,000 psi |
| FKQ640-6 | 640 L | 6 | 3,000 psi |
| FKQ640-7 | 640 L | 7 | 3,000 psi |
| FKQ800-7 | 800 L | 7 | 3,000 psi |
| FKQ960-7 | 960 L | 7 | 3,000 psi |
| FKQ960-8 | 960 L | 8 | 3,000 psi |
| FKQ1280-8 | 1,280 L | 8 | 3,000 psi |
| FKQ1280-10 | 1,280 L | 10 | 3,000 psi |
| Custom BOP Control Unit | Project-specific | 10 to 12 or more | Project-specific |
Nominal accumulator capacity does not equal guaranteed usable fluid volume.
Actual usable volume depends on nitrogen precharge, maximum charging pressure, minimum final operating pressure, ambient temperature, bottle arrangement and required function sequence.
The final model is therefore confirmed only after the hydraulic operator data and project requirements have been reviewed.
Safety, Monitoring and Optional Equipment
| Feature or Option | Purpose |
| Hydraulic Relief Valve | Protects the circuit from excessive pressure |
| Check Valve | Prevents reverse flow from the accumulator bank |
| Accumulator Isolation Valve | Allows individual bottles or banks to be isolated |
| Pump Pressure Switch | Controls pump start and stop settings |
| Low-Pressure Alarm | Warns when accumulator pressure falls |
| Low-Level Alarm | Monitors reservoir fluid level |
| Guarded Shear Control | Reduces the risk of unintended shear ram operation |
| Function Position Indicator | Shows the selected BOP or valve position |
| Emergency Control Station | Provides another operating location |
| PLC and Touchscreen | Displays pressure, functions and alarms |
| Data Logging System | Records commands, pressure status and alarm events |
| Explosion-Protected Electrical Package | Supports installation in a classified area |
| Insulated Control House | Protects equipment in cold or exposed locations |
| Air Conditioner | Controls enclosure temperature in hot climates |
| Hydraulic Tank Heater | Maintains suitable fluid temperature |
| Stainless-Steel Tubing | Improves offshore corrosion resistance |
| Manual Backup Pump | Adds another emergency charging source |
| Dedicated Shear Circuit | Provides higher pressure for a selected shear function |
Surface BOP Control System Applications
Land Drilling Rig BOP Control System
The API 16D BOP Control Unit operates surface well control equipment on mechanical, electric and automated land drilling rigs.
Typical functions include annular BOP control, single or double ram operation, shear ram control and hydraulic choke or kill line valve operation.
Open-skid units provide convenient maintenance access. In contrast, weatherproof and containerized packages add protection in desert, tropical and cold-region locations.
Offshore Surface BOP Control Unit
Offshore accumulator systems can support fixed platforms, jack-up rigs, drilling barges and other installations that use surface BOP stacks.
Recommended features may include marine-grade coating, stainless-steel tubing, corrosion-resistant fittings, weatherproof enclosures and explosion-protected electrical equipment.
The project should also state the required enclosure rating, salt-spray protection, classified-area requirements and inspection scope.
Workover BOP Control Unit
Compact hydraulic closing units can operate tubing rams, pipe rams, blind rams, annular preventers and selected hydraulic valves during workover or well servicing operations.
These systems often prioritize reduced footprint, lower transport weight, compact bottle arrangements and simple local or remote controls.
Well Testing and Completion Support
A hydraulic BOP control package can operate selected surface pressure-control equipment during drillstem testing, production testing and completion work.
However, the required function count and accumulator capacity depend on the installed equipment and approved operating procedure.
Koomey Unit Replacement and Rig Upgrade
Old BOP control hoses, rigid tubing, fittings and junction boxes can also form part of the replacement scope.
How to Select an API 16D BOP Control Unit
Selecting a BOP closing unit only by reference model can cause slow response, insufficient usable fluid or unnecessary oversizing.
BOP Stack Information
| Required Information | Details to Provide |
| Annular BOP | Manufacturer, model, bore, working pressure and operator volume |
| Ram BOP | Single or double ram, bore and operator type |
| Ram Configuration | Fixed-bore pipe ram, variable bore ram, blind ram or shear ram |
| HCR Valves | Quantity, actuator volume and fail position |
| Diverter Equipment | Element and flow-line valve functions |
| Hydraulic Connector | Lock and unlock volume |
| Additional Functions | Project-specific hydraulic valves |
Hydraulic, Utility and Installation Data
| Required Data | Selection Purpose |
| Opening and Closing Volumes | Determines accumulator capacity |
| Required Function Sequence | Defines usable fluid demand |
| Main System Pressure | Establishes the base hydraulic rating |
| Annular Control Pressure | Determines regulator requirements |
| Shear Circuit Pressure | Determines whether a high-pressure circuit is needed |
| Required Recharge Time | Determines pump quantity and flow |
| Voltage, Phase and Frequency | Determines motor and electrical selection |
| Air Pressure and Flow | Determines pneumatic pump performance |
| Control Distance | Determines remote-control arrangement |
| Ambient Temperature | Determines heating, cooling and fluid requirements |
| Hazardous-Area Classification | Determines electrical protection |
| Available Footprint | Determines skid or container dimensions |
The RFQ should also identify the required driller panel, auxiliary station and emergency control arrangement.
Where available, provide electrical cable length, pneumatic signal-line length, hydraulic hose length and the preferred data communication interface.
Finally, space, access, transport and weight restrictions should be confirmed before the general arrangement is finalized.
Engineering, Factory Testing and Documentation
A project-specific engineering and inspection package may include:
| Document or Test Category | Typical Scope |
| Mechanical Engineering | General arrangement, skid layout and component arrangement |
| Hydraulic Engineering | Hydraulic schematic, function diagram and accumulator calculation |
| Electrical Engineering | Electrical schematic, cable schedule and control-panel drawings |
| Component Data | Pump, motor, regulator, valve and accumulator data sheets |
| Calibration | Pressure gauge and pressure switch certificates |
| Pump Testing | Electric and pneumatic pump operation and automatic control |
| Accumulator Testing | Charging pressure, bank operation and pressure retention |
| Manifold Testing | Regulator adjustment and directional valve function |
| Remote-Control Testing | Driller panel, auxiliary station and status indication |
| Alarm Testing | Audible, visual and PLC alarm response |
| Coating Inspection | Surface preparation and coating report |
| Operation Documents | Installation, operation and maintenance manual |
| Spare Parts | Commissioning and recommended operational spares |
| Compliance Documents | Certificate of conformity and ordered certificates |
The factory acceptance test can verify pump rotation, charging performance, start and stop settings, regulator response, pressure retention, directional valve operation, local controls, remote controls and alarm functions.
When the purchase order requires independent witnessing, agreed inspection points can be coordinated with ABS, BV, DNV, SGS, TÜV or another nominated inspection company.
Installation and Commissioning
Before commissioning, personnel should check every hydraulic connection against the approved schematic. They should also inspect hoses and tubing for transport damage, contamination and correct identification.
Next, technicians should verify the accumulator precharge, fill the reservoir with the approved fluid and confirm electric motor rotation, compressed-air pressure and pump settings.
They can then set the annular and manifold regulators and test each function from the main control manifold.
Afterward, the same functions should be tested from the driller panel and any auxiliary or emergency station.
Commissioning should finish with alarm testing, leakage inspection and a written record of the final pressure settings and function results.
Installation instructions, commissioning procedures and technical support can be included in the supply contract.
Operation, Maintenance and Spare Parts
Routine inspection helps the BOP accumulator system retain its stored hydraulic capacity and response speed.
| Inspection Item | Typical Check |
| Accumulator Pressure | Verify normal system pressure |
| Nitrogen Precharge | Check according to the approved procedure |
| Reservoir Level | Confirm adequate control-fluid volume |
| Control Fluid | Check cleanliness and condition |
| Pump Settings | Verify start and stop pressure |
| Electric and Pneumatic Pumps | Check operation, output, noise and leakage |
| Filters | Inspect and replace when required |
| Hoses and Tubing | Check for leakage, damage and corrosion |
| Directional Valves | Verify smooth operation |
| Pressure Regulators | Confirm stable output pressure |
| Pressure Gauges | Check calibration status |
| Alarms | Test audible and visual response |
| Heating and Cooling | Confirm normal enclosure temperature |
| Protective Coating | Repair damage before corrosion develops |
Only dry nitrogen should be used to precharge the accumulator gas chamber. Oxygen and compressed air must not be used.
Before removing an accumulator bottle, pump, valve, regulator, filter or pressure gauge, technicians must isolate and fully depressurize the relevant hydraulic circuit.
Why Choose SGPE?
Engineering Based on the Installed BOP Stack
The proposed configuration is reviewed against the actual operator volumes, function sequence, control pressures, accumulator demand, pump output and remote-control requirements.
Clear Function Identification
The manifold and control panels can follow the approved BOP stack arrangement. Clear labels and stack graphics therefore help the crew operate, test and maintain the system.
Koomey and FKQ Replacement Review
For an existing FKQ, FKDQ or Koomey unit, the compatibility review covers the nameplate, hydraulic schematic, accumulator data, pump information and connection layout.
Factory Function Testing
The FAT can simulate accumulator charging, local and remote operation, pressure regulation, alarm response, pump control and pressure retention before shipment.
Complete Surface Well Control Supply
A combined supply helps buyers coordinate hydraulic functions, connections, technical documents, inspection requirements and shipment arrangements.
Frequently Asked Questions About API 16D BOP Control Units
1. What is an API 16D BOP Control Unit?
An API 16D BOP Control Unit stores and delivers hydraulic power for surface BOPs, diverter systems and related well control equipment.
A complete package commonly includes accumulator bottles, a reservoir, charging pumps, regulators, directional valves, alarms and local or remote panels. Because the unit stores hydraulic energy in advance, it can operate annular BOPs, ram preventers, shear rams and HCR valves without waiting for the pumps to build pressure from zero.
2. Is a BOP Control Unit the same as a Koomey Unit?
Crews often use “Koomey unit” as a general name for a surface BOP accumulator system. However, the term does not define one specific model or capacity.
For a Koomey unit replacement, the supplier should review the existing nameplate, schematic, accumulator capacity, pump arrangement, controlled functions, outlet connections and remote panel layout. This information helps confirm hydraulic capacity and interface compatibility.
3. How does a hydraulic BOP control system work?
Electric or air-driven pumps deliver control fluid from the reservoir to nitrogen-precharged accumulator bottles. The compressed nitrogen then stores hydraulic energy.
When the driller selects a function, the control manifold directs the stored fluid to the correct BOP circuit. After the function finishes, return fluid flows back to the reservoir, while the charging pumps restore accumulator pressure.
4. What equipment can a BOP accumulator unit control?
A correctly sized BOP accumulator unit can operate annular BOPs, fixed-bore and variable bore rams, blind rams, shear rams, choke and kill line HCR valves, diverter equipment and hydraulic connectors.
Because every operator has a different displacement and pressure requirement, the complete surface BOP stack and operating sequence must be reviewed before the function count and accumulator capacity are confirmed.
5. What pressure does an API 16D BOP Control Unit use?
Many surface BOP control units use a 21 MPa or 3,000 psi main hydraulic circuit. Regulators reduce the pressure for functions that require lower operating pressure, especially the annular BOP.
Some shear applications need a dedicated circuit up to 34.5 MPa or 5,000 psi. However, this does not mean that every component in the complete system operates at 5,000 psi.
6. How is BOP accumulator capacity calculated?
Accumulator sizing starts with the opening and closing displacement of each hydraulic operator.
The calculation also considers the operating sequence, nitrogen precharge, maximum charging pressure, minimum final pressure, ambient temperature and recharge time. Because nominal bottle capacity does not equal usable fluid volume, operator data must be reviewed before the bottle quantity, bank arrangement, reservoir volume and pump output are confirmed.
7. What is the difference between FKQ, FKDQ and FKD control units?
FKQ systems mainly use pneumatic signals and are common on conventional land and workover rigs.
FKDQ systems combine electrical commands with pneumatic or hydraulic components, while FKD systems use electrical controls, solenoid valves and optional PLC logic. The correct choice depends on control distance, rig layout, utilities, climate, hazardous-area requirements and automation level.
8. Why are electric and air-driven pumps both used?
Electric and air-driven pumps provide separate charging sources.
The electric pump normally handles routine charging. If electrical power becomes unavailable, the air-driven pump can continue operating when sufficient compressed air remains available. Larger systems may use several pumps to meet the specified recharge time and redundancy requirement.
9. Can the package include remote control panels and emergency stations?
Yes. A complete package can include a main hydraulic manifold, driller control panel, auxiliary panel and emergency station.
Depending on the configuration, the remote panel can display pressure, pump condition, alarm status and function position. Critical commands, including shear ram closure, may use guarded switches or two-action controls.
10. Can the unit operate offshore or in harsh environments?
Yes. Offshore packages may use marine-grade coating, stainless-steel tubing, corrosion-resistant fittings and sealed enclosures.
Desert units can include sunshades, dust protection, ventilation and air conditioning. Cold-weather packages may require insulation, heaters, heat tracing and low-temperature seals. Classified-area projects should also state the required zone, gas group, temperature class and certification scheme.
11. Can SGPE replace or upgrade an existing Koomey or FKQ unit?
Yes. The project may involve a direct replacement, accumulator expansion or complete control-system upgrade.
The review should cover the existing model, schematic, bottle data, pump information, function count and connection dimensions. Upgrade options may include greater accumulator capacity, higher pump output, additional functions, a new driller panel, PLC monitoring or updated hazardous-area electrical components.
12. What information is required for a BOP Control Unit quotation?
Provide a BOP stack drawing or a list of required hydraulic functions, together with the opening and closing volume of each operator.
The RFQ should also confirm the main, annular and shear pressure requirements, function sequence, recharge time, electrical supply, compressed-air supply, remote-control distance, operating environment, hazardous-area classification, inspection scope and delivery destination.
Request an API 16D BOP Control Unit Price
For accurate selection, please provide the BOP stack drawing or a list of required functions, including the annular BOP, ram preventers, shear rams, HCR valves and diverter equipment.
Please confirm the opening and closing volume of each operator. If this data is unavailable, send the manufacturer, model, bore size, working pressure and available technical documents.
The RFQ should also state the system pressure, annular and shear pressure requirements, function count, recharge time, voltage, frequency, compressed-air supply, remote-control distance and operating environment.
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