Case History: Deepwater Drilling Campaign on the Norwegian Continental Shelf in 2008 and 2009: A Success Story

Abstract

Statoil drilled 7 deepwater wells, including one sidetrack, on the Norwegian Continental Shelf from 2007 to 2009. The semi-submersible rig Transocean Leader was used for these drilling operations. All the wells were drilled and abandoned in a total of 460 days, some 135 days ahead of schedule. Gas and/or condensate were discovered in 6 out of these 7 wells. The wells were all drilled with higher efficiency compared to previous deepwater wells drilled on the Norwegian Continental Shelf. The water depth for the wells ranged from 950 m to 1350 m. In the planning phase, the proposed well designs were challenging. However, continuous improvement in drilling performance and risk management were achieved through comprehensive and systematic work in the multi-disciplinary project team of geologists and drilling engineers. Additional contributing key factors to success were good cooperation and planning between the offshore and onshore project team including personnel from the rig contractor and service companies. In the planning phase, early identification of technical challenges and solutions were discussed. Key learning from international deepwater projects in StatoilHydro and other operators were also highlighted. The geological and pore pressure prognosis for all the wells were quite accurate compared to the measured values during drilling and logging. This paper describes how deepwater exploration wells were planned and successfully completed with Transocean Leader. Good teamwork between offshore and onshore contributed to this success story.