A new take on pre-function testing subsea umbilicals
At depths of around 380 metres, newly installed umbilicals in the Vega field in the Norwegian sector of the North Sea can be a challenge to test. Traditionally such testing requires one end of the cable to be attached to a ship on the surface, where insulation and conductor resistance and time domain reflectometry can be measured.
Subsea 7, 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 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. Much like an underwater extension cable, the self-contained system measures insulation resistance, conductor resistance and time domain reflectometry.
The topside junction is placed and operated on the vessel and is designed to operate even during harsh weather conditions. The subsea junction box can withstand pressure of at least 50 bar and can be operated 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 taken into use.
