A new take on pre-function testing underwater umbilicals
Subsea 7, a leading engineering and construction company, and its customer are delighted with their new self-contained underwater umbilical testing system. A new take on pre-function testing, the self-contained system envisaged by Subsea 7 and engineered by MacArtney, takes testing to the seabed, making it faster and more convenient to test in situ.
Instead of raising the cable, the new system lowers it to the cable on the sea floor.
Taking testing below water
At depths of around 380 metres, newly installed umbilicals in the Vega field in the Norwegian sector of the North Sea can be challenging to test. Traditionally, such testing requires one cable end to be attached to a ship on the surface, where insulation, conductor resistance, and time domain reflectometry can be measured.
Subsea 7, a leading subsea engineering and construction company, have taken a new approach to in situ testing and, together with underwater technology company MacArtney Norway, designed an entirely new way of measuring cable function.
Instead of bringing the umbilical to the surface to test, the new system will lower testing connectors down to the cable. Lowering testing equipment to the seabed will save time and lower costs.
Turning concept into reality
MacArtney designed a self-contained testing system with an electrical and fibre-optic downline. The connector garage is lowered to the umbilical by winch and attached to connectors on the umbilical by ROV. Like an underwater extension cable, the self-contained system measures insulation resistance, conductor resistance, and time-domain reflectometry.
The topside junction is placed on the vessel and is designed to operate even during harsh weather conditions. The subsea junction box can withstand a pressure of at least 50 bar and operate at depths of at least 500 metres.
The system tests the umbilical section-by-section, pre-commissioning the entire length of the umbilical flow line system before it is used.
MacArtney Supply:
- Topside junction box
- Winch
- Downline cable with reel
- Electric and fibre optic stress terminations
- Connector basket and subsea junction box
The Vega Project
Subsea 7’s umbilical system for the Vega Project, a daisy-chained installation including flowline expansion spools, static umbilical, dynamic umbilical and a 3” ID MEG line, was installed during the 2009 season. At depths of approximately 380 metres in the Norwegian sector of the North Sea, the installation will service the new Gjøa floating production platform.
About Subsea 7 and MacArtney
MacArtney and Subsea 7 have been working closely together for many years.
Subsea 7 is one of the world's leading engineering and construction companies servicing the oil and gas industry. Our skilled and experienced multinational workforce, in excess of 5,000 personnel, supports our operations in the North Sea, North America, Brazil, Africa and Asia-Pacific. Subsea 7 strongly focuses on the growing, high-tech and high-value deepwater Subsea Umbilical, Riser and Flowline (SURF) sector, but also retains a leading role in the key shallower water markets in the North Sea and Asia-Pacific.
MacArtney A/S is a global supplier of underwater technology specialising in the design, manufacture, sales, and service of various systems for offshore operators, surveyors, the renewable energy sector, ocean sciences, security forces, and navies worldwide. MacArtney offers a range of advanced and reliable systems from proven components, cables and connectors, to state-of-the-art integrated packages, including fibre optic telemetry systems and remotely operated towed vehicle systems.
