|Location:||Tornerose Well, Barents Sea, Norway|
|Water Temperature:||No data|
Initial ROV survey: 10 August 2006
|Gas & Oil Company||Statoil|
|SERPENT Representative:||Dr Daniel Jones|
This Quick Look Report summarises the recent SERPENT work carried out at the Tornerose well in August/September 2006. The Tornerose well is located 125 km north-west of Hammerfest, in production licence block 110B ( Figure 1 ). It is the last of the five wells that have been included in the SERPENT collaboration with Statoil in 2006. SERPENT research at the Tornerose site was specifically aimed to investigate the variation in sedimentary characteristics and biological community composition with space and time at the drilling location. This involves visual assessment of drilling impact on the seafloor and associated fauna. In addition we attempted to collect specimens for further taxonomic and molecular analyses.
The ROV onboard the Polar Pioneer (operated by Transocean) was used to collect four straight line video transects (centred on the well head) during the pre-drilling survey and eight during the post-drilling survey. Additional visual footage was also collected during the SERPENT visit to generate accurate sediment impact maps (detailing the visual, horizontal extent of the drill spoil). The transect lengths generally extended out to 100m from the well head. This video footage was also used to assess and compare changes in the composition of the biological communities and to visually characterise the drilling related impacts on the sediment environment.
An approximate measure of sediment accumulation was obtained by setting a series of marker buoys (labelled at 10 cm intervals) at strategic points around the well head. Prior to any drilling activity, four buoys were set 10m N, WNW, NE and S of the well centre, and a further three buoys at 22m, 50m and 100m N of the well centre. Additional observations on sediment accumulation were made by measuring the depth of the distinct surface layer on collected sediment ROV push-cores ( Figure 2 ). Baited trap experiments were also conducted at Tornerose, in order to assess the composition of the local scavenging community ( Figure 3 ).
Sediment push-core operations at Tornerose
The baited amphipod trap laid at Tornerose was extremely successful, retaining approximately 1000 amphipods ( Figure 3 ). The sardine bait was completely consumed, with only sardine vertebrae and rib bones remaining. The cotton rag was also partially consumed. Amphipods were transferred to formalin and preserved for identification and molecular analysis later on.
Baited amphipod traps deployed at Tornerose.
This method of sampling retains specimens in relatively pristine condition for further taxonomic and molecular analyses. Captured species included ophiuroid starfish Ophiactis abyssicola and the larger Ophiopleura borealis.
At all times and throughout all survey ROV dives, large cod fish were observed via the ROV camera. Zooplankton composed of krill (likely Meganyctiphanes norvegica ) and chaetognaths (planktonic arrow worms). Around 100m south of the well head, redfish were noted, likely to have been Helicolenus dactylopterus. North of the well head at 50m, a hexactinellid sponge (glass sponge) was seen, with sea anemones and stylasterines (calcareous upright or encrusting hydrocorals).
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