Ekofisk is located in the southern part of the North Sea, 300 kilometers southwest of Stavanger. In addition to the Ekofisk field the area consists of the Eldfisk, Embla and Tor fields, all of which are part of production license (PL) 018. All four fields are operated by ConocoPhillips on behalf of the license co-venturers.
The total number of manned and unmanned installations that have been in operation in the Greater Ekofisk Area is close to 30. The oldest one is from 1973, the newest one - the subsea installation 2/4 VA - from April 2010. Several of the installations are now ”cold”, i.e. they are no longer in use - and many of them are in the process of being removed. At the same time the owners invest in re-development - and the fields are now being prepared for the next 40 years.
First Field on the Norwegian Shelf
The Ekofisk field was discovered late in 1969, and production started on June 9, 1971. The area has been developed through several stages. The Ekofisk field with central processing facilities was developed in the early 1970’s. The first few years the oil was loaded from buoys on the field. From 1975 the oil and NGL (natural gas liquids) has been transported through a pipeline to Teesside in the UK, whereas the gas has been brought ashore through a pipeline to Emden in Germany from 1977.
The water depth in the Greater Ekofisk Area is 70-80 meters. Due to a drop in pressure the seabed has been subsiding over the years. Efforts to protect the platforms against the effects of the subsidence started as early as in 1985. All steel platforms at the Ekofisk Complex were jacked up six meters in 1987, and in 1989 a protective barrier wall was installed around the Ekofisk Tank. The subsidence of the seabed has decreased in recent years.
Water Injection Increases Production
As part of the desire to continually increase the production rate in the Greater Ekofisk Area, the water injection platform Ekofisk 2/4 K was put on stream in December 1987. The water injection capacity in the field has later been increased several times, and the latest addition was the 2/7 E platform on the Eldfisk field. In 2011, the total injection volume in the Greater Ekofisk Area is approximately 650,000 barrels of water per day.
Ekofisk II and Extended License Period
A new plan for development and operation of the Ekofisk field (Ekofisk II) was adopted in 1994, at the same time as the license period was extended to 2028. A new Ekofisk Complex with two new platforms was installed on the field – a wellhead platform was installed in the fall of 1996, and a new processing and transportation platform was installed in August 1997. Ekofisk II came on stream in August 1998. The Ekofisk, Eldfisk, Embla and Tor fields are tied in to the new field center.
Ekofisk Growth Project
The Ekofisk Growth Project is intended to increase the production, the processing capacity and regularity from the Greater Ekofisk Area. The Ekofisk 2/4 M platform, which came on stream in 2005, is part of this project.
In 2001/2002, the Norwegian authorities approved the Cessation Plan for Ekofisk I. The concrete substructure of the Ekofisk Tank is left in situ, while the other shut down facilities are to be removed. By 2014, nine steel platforms will be removed.