Butch field is located in production licence PL405/405B on the Norwegian continental shelf in blocks 7/9, 7/12, 8/7, 8/8 and 8/10, 12km north-east of Ula and 18km north-east of Gyda fields.

The field lies 250km off the Norwegian coast and 40km off the UK boundary, in water depths between 65m and 70m. PL405 was awarded in 2007 and PL405B was awarded in 2008.

The offshore field is operated by Centrica Energy, which holds a 40% interest in collaboration with Suncor Energy (30%), Tullow Oil (15%) and Faroe Petroleum (15%).

Production from the Butch field is scheduled to start in 2019 and is expected reach to a peak of 35,000bbl/d and gas production of 550,000 standard cubic metres a day (Sm³/d).

The field development is estimated to cost between Nkr6bn and Nkr7bn (between £500m and £600m).

Butch field discovery and geology

The field was discovered in 2011 on drilling the discovery well 8/10-4 using the Maersk Guardian drilling rig. Appraisal drilling on the prospect was performed in first half of 2014.

Butch field is a stratigraphic pinch-out trap located on the side of a salt dome. It consists of high-quality light crude oil in the Upper Jurassic reservoir of the Ula formation.

Pressure and temperature in the reservoir are 409bar and 121°C respectively.

Butch field development details

The Butch field development plan includes a subsea tie-in to the Ula field, where the well stream from Butch field will be transported to the BP-operated Ula platform, for processing. Oil produced from the field will be exported to Ekofisk and further into Norpipe to Teeside terminal in England through Ula oil export pipeline.

The gas produced from the field will be injected into the Ula field reservoir for improving oil recovery. The development activities include drilling and completing two production wells and a water injection well.

Subsea infrastructure on the field is scheduled to be installed between 2016 and 2018 with drilling planned to be completed by 2018.

Technology used in Butch field development

An innovative drilling technique was employed for the first time on the Butch field. It involved drilling a pilot hole 360m-deep to detect the presence of shallow gas using a well intervention vessel and coiled tubing drilling (CTD) instead of a traditional rig.

Key players involved with the Butch field development

Centrica Energy signed long-term partnership agreements with Subsea 7, Aibel and DNV GL for planning and executing the Butch development project.

Aibel will assist in all field development projects by Centrica on the Norwegian Continental Shelf that includes the Butch field.

Subsea 7 has been selected to perform the front-end engineering and design (FEED) study that will be jointly conducted by Subsea 7’s partner Granherne.

Norconsult conducted a technical verification of the required topside modifications to assess the risks and verify the costs.

Island Offshore was contracted to drill the pilot hole at the Butch field. Equipment from Baker Hughes was used along with special equipment supplied by Island Offshore.

Ula oil field details

The Ula oil field lies in block 7/12 (PL019A) in the southern Norwegian section of the North Sea in approximately 70m of water. Production on the BP-operated field began in October 1986 following the field discovery in 1976.

The field infrastructure includes three platforms for drilling, production and accommodation that are interlinked by bridges.

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