Management of the Ekofisk Cessation Project (ECP)

Abstract This paper describes the major issues which have been addressed in the conceptual phase of the project in order to manage the project in a controlled manner. These issues are.Establishment of a philosophy and strategy for the Cessation Process.Clear definition of the Cessation Phases, activities and interfaces.Establishment of a strategy for identification, execution and Implementation of required special studies.Establishment of a quality plan.Establishment of terms and definitions to be utilized in the project.Establishment of a plan for external communication. Introduction The Ekofisk field was discovered in 1969 in the southern part of the Norwegian Continental Shelf, Today twenty-six platforms are installed in the Greater Ekofisk Area in water depths of approximately 240 feet (73 m). A re-development of the Ekofisk Field, called Ekofisk-II, is now in progress. When Ekofisk-H comes on line in 1998, two new platforms will be installed and twelve of the existing platforms will cease operation, see figure 1. According to proposed new Norwegian law the operator, on behalf of the license group, shall present a p[an for cessation of production to the Norwegian authorities 2-5 years before platform operations cease. In this cessation plan the licensee will examine the various disposal options that may be relevant to the particular platforms and pipelines, The four opt]ons to be examined are continued use in petroleum activities, other uses, abandonment in place and removal. For each disposal option considered in the cessation plan, technical. economical. safety, environmental, fisheries, sea and air traffic considerations have to be discussed. The licensees will in the cessation plan recommend a final disposal option to the authorities. However, the final decision for how to dispose of the installations lies with the authorities. Philosophy & Strategy In accordance with the Ekofisk-II Plan for Development and Operation (PDO) submitted in December 1993 the Ekofisk cessation philosophy is to decommission the installations when normal operations cease, make them tidy and safe and store them in situ until disposal is acceptable to both the authorities and licensees. This philosophy still applies, see figure 2. The authorities are in agreement that the disposal solution and timing need to be agreed on a case-by-case basin The assessments which are made in the conceptual and feasibility phases of the Ekofrsk Cessatton ProJect will provide the necessary basis for preparation of the cessation plan for the twelve platforms which will cease operations as a consequence of Ekofisk-II. Based on the Ekofisk cessation philosophy, the strategy when installations cease operation is to decommission and render them cold for a period of time and to defer disposal as long as practicable. The main factors which determine the optimum timing of final disposal are the operating cost associated with a cold installation and the possible change in disposal cost as time elapses (see figure 3).