20 Years of Met-Ocean Data Collection on the Northern Norwegian Continental Shelf
Authors: Lønseth L. , Kvitrud A. 
Published: October 2008

The data collection program for the Norwegian Continental Shelf north of 62°N started in 1976 and is still in operation, gathering Met-Ocean measurements at strategic locations. In situ recorded Met-Ocean data were previously not available from the study area. By this program a long term data base of environmental data is established before development of petroleum resources is initiated. The data form a basis for definition of environmental criteria for design of installations and planning of operations on the shelf. The data also contribute to the data basis for analysis of general climatic trends and regional variations. Access to the data and other results from theproject is unrestricted.

Directional and non-directional wave buoys with internal data recording and satellite data telemetry have been used for wave and meteorological data collection at 7 locations, collecting approximately 40 station years of wave data. Ocean current data have been collected by moored single point current meters and Acoustic Doppler Current Profilers at 16 locations, giving 20 years of current profile data. Stationary weather ships have also been employed. Parts of the data are collected in deep water off the Continental Shelf.

Data have been analysed to determine normal and extreme conditions at different locations. Regional differences of wave climate have been studied, indicating that extreme wave and wind conditions are at a maximum at the Vring area (off Central Norway), with a general reduction of extreme values toward north and east into the Barents Sea. Inter-annual variations of wave conditions have also been studied, with the support of wave hindcast results and long term time series from coastal stations.

Background and organization

For planning of development and operation of installations in the oil and gas fields off shore, a good knowledge of the physical environmental forces acting on the platforms, pipelines, ships, floating production units and so on, is of vital importance. The main factors which are present in every offshore area are the winds, surface waves and ocean currents. In northern areas factors inherent to a cold climate; drifting ice and icebergs, and icing of constructions from sea spray and precipitation, also play an important role. The relative importance of environmental factors depends on the local conditions, and on the type of installations involved.

Reliable knowledge of the environment depends on long series of observations collected over many years. Therefore the data collection must start many years before the design of installations is finalized.

The development of offshore petroleum resources first started in parts of the North Sea where the ocean is relatively shallow, typically less than 100 m. In this area the environmental conditions were also fairly well known. Gradually the activity expanded north to deeper ocean areas with a more harsh physical environment. Water depths in areas of interest are from around 250 m at Tromsøflaket and in the Barents Sea, to more than 1400 m at the Vøring Plateau.