Heidrun

Heidrun Oil and Gas Field Profile

Location and Geography

The Heidrun oil and gas field is located approximately 175 kilometers off the coast of Mid-Norway in the Haltenbanken region of the Norwegian Sea. The field is situated in water depths of around 350 meters.

Discovery and Development

The Heidrun field was discovered in 1985 by Conoco, which was the operator during the exploration and early development phase. The first discovery well, drilled in June 1985, encountered a 137-meter oil column in the Lower Jurassic Tilje Formation. Following the discovery, several more wells were drilled to confirm and delineate the field.

Production Start and Current Status

Production from the Heidrun field began on October 18, 1995. Initially, the field was expected to produce slightly more than 750 million barrels of oil, but it has already exceeded these initial expectations. As of recent years, the field produces around 60,000 barrels of oil per day, down from its peak of almost 250,000 barrels per day.

Field Development and Infrastructure

The Heidrun field is developed using the world's first floating concrete tension leg platform (TLP), which is installed over a subsea template with 56 well slots. The TLP is anchored to four concrete foundations on the seabed by 16 tubular steel tethers. The platform includes a combined production and drilling facility, along with a dedicated well intervention tower for well workover activities.

The field has undergone several developments, including the installation of subsea facilities for the northern part of the field, which was brought on stream in August 2000. The field currently has 51 production wells, 24 seawater injection wells, and one gas injection well to maintain reservoir pressure and enhance recovery.

Production and Reserves

The original recoverable reserves were estimated at 177.1 million cubic meters of oil, 44 billion cubic meters of gas, and 2 million tonnes of natural gas liquids (NGL). As of 2011, the remaining recoverable reserves were estimated at 38.3 million cubic meters of oil, 29.4 billion cubic meters of gas, and 1.5 million tonnes of NGL.

Transportation and Export

Oil from the Heidrun field is primarily shipped by shuttle tanker to Statoil's Mongstad crude oil terminal near Bergen for onward transport to customers. Gas from the field is piped to Tjeldbergodden in mid-Norway, where it is used as feedstock for Equinor's methanol factory. Additionally, the gas is exported through the Åsgard transport pipeline to Kårstø near Stavanger and further to Dornum in Germany, a total distance of roughly 1400 kilometers.

Environmental Considerations

The partners in the Heidrun license have invested significantly in environmental measures. A reinjection plant for produced water was installed on the Heidrun platform, allowing for the reinjection of water and any oil or chemical residues back into the reservoir, resulting in zero harmful discharges under normal operations. This facility can handle over 110,000 barrels of water per day.

Additional Developments

In 2015, a new floating storage vessel, Heidrun B, was introduced to receive oil from the Heidrun field. This vessel is designed to be permanently moored at the Heidrun platform for at least 30 years. The field has also been upgraded with a new 4500-tonne gas treatment module to handle gas from the nearby Dvalin gas field, which is tied back to the Heidrun platform.

Operators and Partners

The current operator of the Heidrun field is Equinor (formerly Statoil), with a 12.41% interest. Other licensees include Petoro (58.16%), ConocoPhillips (24.31%), and Eni (5.11%).

Geology

The Heidrun field's reservoir consists of sandstones from the Early and Middle Jurassic age, specifically the Garn, Ile, Tilje, and Åre Formations. The reservoir is heavily faulted, with the Garn and Ile Formations having good reservoir quality, while the Tilje and Åre Formations are more complex. The reservoir depth is approximately 2,300 meters.

Future Plans

The partners plan to maintain Heidrun in production until at least 2045 through additional developments and the drilling of new wells. Continuous efforts are made to optimize production and extend the field's ultimate productive life.

In summary, the Heidrun oil and gas field is a significant production asset in the Norwegian Sea, known for its innovative infrastructure and ongoing efforts to maximize recovery and minimize environmental impact.