|Location:||Ragnarokk, North Sea , Norway|
|Water Temperature:||No data|
Pre-drilling SERPENT visit 26 – 30 July 2007
|Gas & Oil Company||Statoil|
|SERPENT Representative:||Dr Andrew gates|
This mission report summarises the recent SERPENT visit to the West Epsilon jack-up drilling rig at Ragnarokk. The visit was carried out in collaboration with Statoil in July 2007. Ragnarokk is located in Block 16-2 of the North Sea , West of Stavanger and is one of three wells included in the SERPENT collaboration with Statoil for 2007.
The aim of the visit was to take pre-drilling video transects and push core samples for comparison with similar information gathered after drilling during a second visit towards the end of the well.
The West Epsilon, operated by Sea Drill, is the first jack-up rig that SERPENT scientists have visited; SERPENT visits normally take place semi-submersible rigs. The visit gives the opportunity to study the impacts caused by different types of drilling rigs.
The pre-drilling visits also offer a good opportunity for SERPENT researchers to gain detailed understanding of the study area which is beneficial in the planning of subsequent visits to the site.
During the “pre-spud” visit the Oceaneering operated Magnum 034 work class ROV was used to collect video transects centred on the proposed location of the BOP prior to drilling disturbance. The transects also passed areas of sediment disturbed by the deployment of the legs supporting the drilling rig.
Sediment samples were collected using ROV push corers in order to establish the chemical characteristics and the meiofaunal composition of the undisturbed seabed at the well location before drilling began. Samples were also taken at the site of disturbance caused by the deployment of the legs for comparison with the undisturbed sediment.
Additionally, video footage and a small number of specimens were taken of some of the typical organisms observed in the area to facilitate the identification of those seen in the video transect surveys.
Sea urchins (echinoids) were the most abundant organisms observed during the Ragnarokk pre-drilling visit. The image on the left shows a typical view from the video transects and on the right is a close-up screen grab of an individual, possibly Echinus acutus.
Asteropecten sp (left) was a common species of Asteroid observed at Ragnarokk. Hippasteriaphrygiana (right) was also seen regularly at the location. In this image the tube feet can be seen on the arms on the right of the picture.
Gastropod mollusc; possibly the common whelk, Buccinum undatum. The examples here are seen with the siphon extended (left) and with an anemone attached to the shell (right).
Organisms encountered occasionally at Ragnarokk. Top left: An unidentified flatfish, a paleamon shrimp and two echinoids seen on the sea bed. Top right: The only example of a scallop (Pecten sp.) seen at Ragnarokk. Bottom left: A pennatulid (sea pen), probably Pennatula phosphorea viewed from above, illuminated by the light on the seven-function manipulator arm. Bottom right: A phyllodocid polychaete worm possibly Ophidromus flexuous seen on the surface of the sediment.
For further information please contact:
Dr Andrew Gates, SERPENT Project, National Oceanography Centre, Southampton, UK.
or Dr Daniel Jones, SERPENT Project, National Oceanography Centre, Southampton, UK