Viper Innovations: power delivery and umbilical cable optimisation for long offset tiebacks
14 June 2021
The following information has been taken from the technical paper ‘Power Delivery and Umbilical Cable Optimisation for Long Offset Tiebacks’, written by Surrinder Retour, Paul Overton, Daniel Denning, and Neil Douglas of Viper Innovations. The paper presents a study into the physical and practical limitations of different power transmission techniques for long offset tiebacks. The results from the study present a definitive operating envelope for varying offset tiebacks and subsea power demands. The study is supported by in-depth performance analyses covering a range of power transmission techniques and umbilical cable designs. Download the technical paper here.
Over the past 20 or more years, there have been several subsea field developments where the tieback distance has been defined as ‘long offset’, typically with the flow-line and umbilical lengths being over 70km and up to 150km.
To date, the electrical power transmission techniques and umbilical designs have simply been ‘extensions’ of the technology used for more conventional ‘short offset’ developments. There is a trend for ever-increasing offset distances and higher power demands from subsea consumers, typically subsea processing equipment. The higher power levels and increasing offsets mean that there is now more focus on power delivery capacities.
Extensive work has been undertaken to re-evaluate the physical and practical limitations of different power transmission techniques and to assess the impact of different umbilical designs on these limitations.