Page 46: of Offshore Engineer Magazine (Jan/Feb 2014)

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and diagnostic data, with accurate real time IR measurements, down to

Extending <1Kohm, and line current and volt- age measurements.

Subsea

To maintain their ef? ciency, data from the units is periodically ana- umbilical lyzed, and con? guration updates carried out on the installed units. life

V-LIFE underwent a ? eld trial on a North Sea ? eld with known

IR problems. The ? eld trial started

Viper Subsea’s V-LIFE in July 2012, and the IR was is increasing insulation increased from less than 50kO to 25MO in less than two months. resistance to extend subsea

The unit remains operational, with systems’ life expectancy.

the IR being kept at a high level and has been independently veri? ed.

Centrica Energy’s exploration and

By Neil Douglas, production business was one of the ? rst companies to commercially use V-LIFE. managing director, Viper Subsea

Centrica’s Birch, Larch and Sycamore t is well understood that water and susceptible to water ingress, include sub- wells, located in the UK North Sea, are all electricity don’t mix well. Since the sea umbilicals, distribution units, electri- tied back to the Brae Alpha platform via a

I advent of electro-hydraulic control cal connectors, and ? ying leads. All single subsea umbilical. These had been systems, this fact has presented an ongo- of these are used to transport electrical shut-in, having experienced some electrical ing challenge to subsea engineers as they power and communication signals from a power problems with the control system.

try to ensure electrical conductors within surface facility to the subsea production Centrica used V-LIFE to improve the cables and connectors are kept dry for the equipment. electrical insulation on the umbilical. design life of subsea production systems. Along with the potential loss of pro- The IR has been increased by a factor of

Design, quality, manufacturing, and duction, failing insulation resistance can more than 200. This increase avoided the test processes have improved over time. also mean extra electrical hazards for need to procure and install a new umbili-

However, the industry still has to work technicians working on topside electrical cal. Production has since increased from with the legacy of installed equipment power units. the Birch and Sycamore Fields and safety that was designed and manufactured Previously, in the event that sea water has been improved. some time ago. If sea water penetrates penetrated electrical cables, there was V-LIFE has since been adopted by a electrical insulation barriers, operators no alternative to a costly subsea inter- number of other North Sea operators to face an expensive problem, as well as a vention to fault ? nd and replace failing extend subsea equipment life expectancy, potential safety issue. equipment. postpone early ? eld abandonment, negate

The introduction of sea water into the Viper Subsea has been working on a the need to install new umbilicals, or to electrical cables and connectors causes solution to overcome the effect of water increase technical margins to improve a reduction in insulation resistance (IR), penetration. V-LIFE uses a combination operability and safe working of produc- which nearly always continues to deteri- of dynamic electro-kinetic and electro- tion control systems. orate to a point where a complete failure chemical processes to reverse the effect To date, it has a 100% success rate in occurs. Such a failure could potentially of water penetration into or through increasing IR. lead to loss of production. electrical insulation material. It is con- Details of the exact technique used

Seabed-based components form nected to the umbilical at the topsides remains con? dential, as patent is pending part of the subsea distribution system only, which means installation requires and has not yet been published. V-LIFE no subsea intervention. has been veri? ed by an independent UK

Improved resistance

The outcome is an increase in the University.

O 35M insulation resistance of electrical distri- bution components, which increases life Neil Douglas is the

O 30M expectancy on failing equipment. founder and manag-

O 25M

V-LIFE is designed to be compatible ing director of Viper 20MO with all ageing and new subsea produc- Subsea. He graduated 15M

O tion control systems, including those with an electronics 10M

O operating with both separate power and degree from Bristol 5M

O

Insulation resistance communications networks, and systems University before 0.165MO 5 0 10 15 20 25 where communications are superim- joining GEC Marconi.

Number of operational days posed on the power. He served as global technical director for

The V-LIFE unit automatically logs GE Oil & Gas before leaving to co-found

Insulation resistance increased during testing.

various system electrical parameters Viper Subsea in 2007.

January 2014 | OE oedigital.com 48 048_OE0114_subsea2.indd 48 12/19/13 4:03 PM