Abstract

15 platforms in the Ekofisk Area in the North sea were considered redundant as a result of the Ekofisk II project and were designated Ekofisk I. A Cessation plan and an Impact Assessment were prepared by Phillips as operator for the License PL018 owners and issued to the Norwegian Authorities in October 1999. Were evaluated during the planning process, and several alternatives for each option were subjected to further studies. The recommendation was to remove all steel platforms for onshore recycling; to leave the 242 km of buried pipelines, the seven drill cutting piles and the concrete structures in-situ.

The subsequent Authority approval was given in December 2001 to decommission and dispose of these platforms as recommended by year 2013, except those that may still be in operation at that time. The only remaining permit at this time is a confirmation from the Norwegian Parliament to allow the Ekofisk Tank concrete structure to be left in-situ. Decommissioning of the first platforms started in August 1998, and ten platforms have so far been permanently shut down. Well plugging operations are in progress, and three of the outlying platforms have been plugged so far. It is expected that all wells on these platforms will be plugged by end of 2003. The commercial prequalification and bidding process for removal of the first two platforms, the Tank topsides and the Tank cleaning work has been started.

Contract awards are expected in 2003. Development of alternative removal technology is an integral part of this project, and bidding on the two first platform removals has been reserved for the "Single-lift" concepts. These are vessel concepts capable to remove topsides or jackets in one operation, and will, if realized, be able to rationalize the offshore removal operations considerably. The Ekofisk I Cessation Project is so far the largest offshore decommissioning project ever undertaken, and this paper explains the main challenges overcome and the ones still ahead of us.

Introduction

In 1969, Phillips discovered the giant Ekofisk field, almost 200 miles offshore Norway's coast in the center of the North Sea. Production from Ekofisk began in 1971, and by 1980 seven fields in the Ekofisk area were producing. The eighth field, Embla, began producing in 1993.

In August 1998, Phillips began producing oil and gas through the Ekofisk II facilities, a massive redevelopment of the original Ekofisk Complex. Redevelopment of the facilities has significantly reduced operating costs. Ekofisk II will enable Phillips to produce profitably from the Norwegian North Sea through at least 2028.

The 1994 Plan for (Re)Development and Operation (PDO) of Ekofisk II included the building of two new platforms to replace the older Ekofisk I installations. This included also a commitment to decommission and dispose of these installations in a safe, environmentally responsible an

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