Eirik Raude dips into Obelix

Drilling was due to get underway last week on Norsk Hydro's Obelix prospect in the Barents Sea, the first of three planned wells in this sector using the semiEirik Raude. The rig left its base just north of Bergen a fortnight ago, arriving at the offshore location last Tuesday, with support from the supply vessels Northern Corona and Skandi Admiral.

Obelix lies in 368 m of water, in production license 225, 195-km offshore the north Norwegian coast, in a location between Soroya and Bear Island. Hydro considers this an oil prospect and will be investigating carbonate rock intervals of Permian age. To comply with the Norwegian Pollution Control Authority's (SFT) regulations for this normally off-limits region, the well must be drilled with a minimal amount of discharge compared with standard exploration wells elsewhere on the Norwegian shelf.

Hydro will be allowed to discharge drill cuttings and drilling mud from the hole section for surface casing to a depth of 100 m below the seabed. But the materials dumped will amount to no more than 55 cu m of seawater and chemicals, and these must cause no risk to marine organisms. Once surface casing has been set, the operation must continue in a closed system, with even rainwater on the drill floor having to be collected.

According to the National Petroleum Directorate, one challenge still to be resolved concerns the thread compound applied to the drill pipes to protect them before they are assembled to make up the drill string. SFT's rules state that 1.5 kg of this compound can be legally discharged during drilling; however, the substance incorporates chemicals SFT classifies as environmentally harmful. Hydro will definitely be allowed to discharge 1 tonnen of rig detergent during the 26-day operation.

1/24/05