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Knut has been working in the offshore industry for 30 years in operational, project and commercial management roles for companies such as Heerema, Subsea 7, ConocoPhillips and Aker BP. Over the last 5 years he has been closely involved following up the development of the Electrical Heat Trace Flowline system that Subsea 7 has developed. Working in the Subsea Alliance where Aker Solution, Subsea 7 and Aker BP work together, Knut is responsible for delivery of the Electrical Heat Trace Flowline system on the Aker BP’s Ærfugl project.
Knut holds a Master of Science degree in Offshore Technology from the Technical University in Delft.
Use of Technology Enables Development of Field in Norwegian Sea
The Ærfugl field is a gas condensate field located in the Norwegian Sea to the West of Skarv and Idun fields. The first phase is planned developed with 3 off single slot templates as a 20 km long tie-back to the Skarv FPSO connected to the existing subsea infrastructure. Heat input into the flow line system is required during both plateau and off-plateau production periods. The new enabling technology Electrically Heat Traced Flowline (EHTF) will be utilized to enable system start-up and shut down, and to maintain the production fluids outside of the hydrate envelope during steady state operation. The Ærfugl EHTF system consists of an electrically heated 10” flowline inside a 16” carrier pipe (Pipe In Pipe). The large annulus between the 10” and the 16” allows for good insulation, and combined with reduced annulus pressure, a U-value of less than 0.5 W/m²/K is achieved. Such a low U-value allows for a more passive system where only limited power is required from the heating system. The Ærfugl EHTF system is based on a topside transformer. The power cables goes directly from the topside bus bar via a dynamic and static power umbilical system to the In-Line Power Inlet Structure (ILPIS) on the Electrically Heat Traced Flowline (EHTF). There is as such not any sophisticated components subsea to transform or split the current. All components that may need maintenance and repair are located topside. This gives a very high availability of the subsea system. This paper will address EHTF specificities on Ærfugl project, and provide a high level description of the intensive qualification program performed for the project.
Authors: Arne Skeie and Guy Mencarelli, Subsea 7