Marathon-Braemar Field Development Subsea Control System
The Location
eProduction Solutions UK Ltd’s Subsea Control System was designed for a single subsea satellite well on the Braemar high pressure gas field, North Sea, tied back to Marathon’s East Brae host facility.
The Requirement
Operation and monitoring of a single subsea well with the capacity for future expansion to control and monitor up to 4 additional wells.
The Solution
eP designed, manufactured and installed a modular ROV installable subsea production control system, with the required capacity for expansion. The integrated system provides the requisite monitoring, control and shutdown functions by means of multiplexed electro-hydraulic control, using on-power communications between a surface MCS and SCM, via a composite services umbilical and appropriate subsea distribution units.
The Subsea Production Control System is comprised of:
Subsea Control Module
Designed to incorporate guidance and lock-down systems to allow the SCM to be installed and retrieved using ROV based intervention techniques.
The SCM is configured to control one well, has the capacity for expansion to control up to 4 wells, and has 12 hydraulic functions, 1 high pressure and 11 low pressure. Hydraulic and electrical input/output connections are made through the base of the SCM using low force hydraulic couplers and wet mateable electrical connectors. The mating halves of the input/ output connections to and from the SCM are housed within interface plates that are positioned with the respective SCM and SCM mounting base assemblies. A ten liter accumulator is accommodated within the control module to prevent low pressure drop outs during valve operation.
Master Control Station
The MCS is a free-standing cabinet consisting of two Rittal 19” rack cabinets containing removable 19” rack modules. These provide all of the necessary control and monitoring for the Braemar subsea system.
The control system is based on two dual redundant GE Fanuc 90-30 PLCs interfacing to the subsea system via two serial interface links.
The MCS PLC system provides three main system interfaces:
- DCS Control / Monitoring
- Citect SCADA Control / Monitoring
- Subsea Control / Monitoring communications interface
Hydraulic Power Unit
The HPU has been designed with sufficient accumulation to operate all valves on two subsea trees in one complete cycle. The unit is fully contained in a stainless enclosure accessible with the operator interface area situated on the front panel. Access to the enclosure for maintenance work is located at the end of the HPU. At the operator access end of the HPU is an area dedicated to interface hook up for hydraulic outputs and links to the control system.
The system is flushed to NAS 1638 Class 6 to help extend the life of components.
Electrical Power Unit and Communications
The EPU will provide dual redundant power supply feeds and coupled communication on 10 mm twisted pairs to the subsea umbilical network via terminal connection. Communication signal is transmitted and received through the power lines using “LonWorks” interface technology.
The Benefits
The Subsea Control System and HPU is a cost effective solution which meets all of the customers requirements. Other benefits of the system are:
The smaller diameter of the cable compared to traditional umbilicals:
- Reduces the weight
- Reduces transportation and installation costs
- Reduces ongoing maintenance costs
- Less expensive components exposed to failure
- Easily retrievable
- Reduces CAPEX costs
The Services and Solutions
eProduction Solutions UK Ltd is a one-stop provider of complete automation systems for producing oil and gas fields and pipelines. The comprehensive solutions use superior technology and thorough support to empower users to make better decisions. These decisions can be made from their desktop for more efficient operations.
eProduction Solutions UK Ltd provides solutions with a comprehensive list of in-house integrated products and services. Our solutions are rounded out with our expertise in artificial lift, optimization, production operations, and multiple configurations. Our solutions are available for onshore fields, offshore platforms, onshore gas fields, pipeline monitoring, and can be web based. eProduction Solutions UK Ltd addresses all types of wells with its system including rod pumping, injection, ESP, gas lift, plungerlift, and free-flowing. All parts of our solutions are built upon state of the art industry technology and on proven field results.
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