Controls

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Controls Overview.png

Simplified Electrohydraulic Multiplex System Circuit Diagram

Simplified Electrohydraulic Multiplex System Circuit Diagram.png

Uninterruptible Power Supply (UPS)

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  • Provides safe and reliable electrical power to the subsea production controls equipment.
  • Able to maintain a steady supply, even when the main source fluctuates or fails.
  • Provides power for the production control system during input power failure.
  • Rating based on project requirements and capable of maintaining 100% load for a minimum of 1/2 hour (per API 17F)

Electrical Power Unit (EPU)

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  • Provides redundant, conditioned power to the topside and subsea production controls system equipment.
  • It is a modular design based on standard 19 inch units.
  • Local panel meters display the input/output power parameters for all connected subsea equipment.
  • All operating parameters are sent to the MCS for display and alarming.

Master Control Station (MCS)

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  • Main operator interface
  • Typically a PC or PLC based
  • Modular design based on standard 19 inch units
  • Displays information from the subsea equipment
  • Implement interlocks to prevent inadvertent errors
  • Executes shutdowns
  • Monitors functions and alarms on specific conditions
  • Record data and alarms
  • Event Logging

Human Machine Interface (HMI)

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  • Main operator interface
  • Mimics the actual system control circuits and equipment interconnections
  • Displays information from the subsea equipment
  • Allows the operator to change set points, view and setup trends, generate reports, and execute commands

Remote Operator Station (ROS)

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  • Provides an operator interface with full monitoring and control of the Production Control System.
  • Typically located in the main operator room.
  • Usually consist of a desktop PC with flat screen monitor and printer.
  • Connects to the MCS via a redundant Ethernet link.
  • Offers the same HMI functionality provided at the MCS.
  • Powered by a UPS for continued operation during power failures.

Hydraulic Power Unit (HPU)

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  • Provides clean, regulated pressurized hydraulic fluid to operate actuated functions subsea.
  • Redundant High Pressure (HP) and Low Pressure (LP) circuits are typically provided.
  • Contains Electrical or Pneumatic pumps.
  • Accumulators for stored hydraulic supply and continued operation with power or pump failures.
  • Local control panel for manual operation of pumps, service and maintenance activities.
  • Supply and Return hydraulic reservoir for stored fluid.

Topside Umbilical Distribution Unit (TUDU)

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  • Located close to the umbilical I-tube or J-tube
  • Electrical junction box rated for the environment
  • Fiber Optic junction box rated for the environment
  • Hydraulic/chemical enclosure
  • Hydraulic/chemical supplies w/ block, bleed valves & gauges
  • Return lines to platform
  • Annulus monitor line

Subsea Equipment

  • Umbilical Termination Assembly (UTA)
  • Subsea Distribution Unit (SDU)
  • Subsea Controls Module (SCM)
    • Subsea Electronics Module (SEM)
  • Subsea Controls Module Mounting Base (SCMMB)
  • Subsea Accumulator Module (SAM)
  • Subsea Accumulator Module Mounting Base (SAMMB)

Umbilical Termination Assembly (UTA)

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  • Terminates the umbilical services subsea
  • Distributes hydraulics, chemicals, power and communication services to each tree/control module
  • Includes bend limiters for subsea end of umbilical
  • Bolted flange used to secure the umbilical
  • Designed to provide an efficient offshore handling, installation, and retrieval method
  • Detachable subsea support structure secured to the seabed (stab & hinge, mud mats, piles, etc.)
  • Electric/Optical/ Hydraulic jumpers connected by ROV friendly stab plates

Subsea Distribution Unit (SDU)

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  • Distributes hydraulics, chemicals, power and communication service to each tree/manifold control modules
  • Designed to provide an efficient offshore handling, installation, and retrieval method
  • Detachable subsea support structure secured to the seabed (mud mats, piles, etc.)
  • Flying Leads connected by ROV friendly stab plates and connectors
  • Isolation valves for chemicals and hydraulic supplies
  • Locally mounted control and/or accumulator modules

Subsea Control Module (SCM)

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  • Controls Tree and Manifold valves
  • Monitors the DHPT, Tree/Manifold pressure, temperature, flow, sand and pig detectors
  • Monitors the choke position and upstream/downstream pressures
  • Dual redundant hydraulic/electric supplies and Dual SEM's
  • ROV retrievable
  • Accumulation integrated into the SCM or separated modules
  • Mounted directly to production/injection trees, and manifolds

Control System Drivers

  • Host Facility
    • Water Depth
    • Field Layout
    • Offset(s)
    • Well Location (cluseter/spread), offset distance, no of wells
  • Wells
    • Shut-in Pressure
    • Shut-in Temperature
    • Tree Valve Characteristics - Tree Manufacturer (water depth & shut-in pressure)
    • SCSSV (tubing pressure profile), set depth - supplier (operational characteristics)
    • Mitigation Requirements
      • Hydrate
        • MEOH/LDHI strategy & flow rate
      • Chemical
        • Different types, flow rates
      • Erosion/Sand
        • Erosion Detector
        • Sand Detector
  • Manifolds
    • Functional Requirements - Production Strategy/Operational Requirements
    • Pig Detector
    • MPFM
    • PTT