Oil and gas discovery near the Troll field in the North Sea

09/02/2023 Equinor Energy AS, operator of production licence 923, has concluded the drilling of wildcat well 31/1-3 S and appraisal well 31/1-3 A.

The wells were drilled about 10 kilometres northwest of the Troll field in the North Sea and 130 kilometres northwest of Bergen.

The primary exploration target for well 31/1-3 S was to prove petroleum in the Etive and Oseberg Formations in the Brent Group from the Middle Jurassic. The secondary exploration target was to prove petroleum in the Cook Formation from the Early Jurassic.

The objective of well 31/1-3 A was to delineate the discovery made in the Brent Group in well 31/1-3 S in January 2023.

Well 31/1-3 S encountered a gas column of about 80 metres in the Tarbert and Ness Formations, and an oil column of around 50 metres in the Ness, Etive and Oseberg Formations, approx. 20 metres of which was in sandstone layers with poor to moderate reservoir quality in the Tarbert and upper part of the Ness Formation, and around 65 metres in sandstone layers with moderate to good reservoir quality in the Ness, Etive and Oseberg Formations.

The Cook Formation was water-filled and contained sandstone with moderate to good reservoir quality.

The oil/water contact was encountered at a depth of 3227 metres below sea level in the Oseberg Formation.

Well 31/1-3 A encountered an oil column of approx. 20 metres in the Ness Formation, with sandstone layers of around 30 metres with moderate to poor reservoir quality in the lower part of the Ness Formation.

The oil/water contact was encountered at 3211 metres below sea level in the Ness Formation.

Preliminary estimates place the size of the discovery between 2.7 and 7.4 million Sm3 of recoverable oil equivalent. The licensees will consider tying the discovery into existing infrastructure in the Troll area.

The wells were not formation-tested, but extensive data acquisition and sampling have been carried out.

These are the third and fourth exploration wells in production licence 923, which was awarded in APA 2017.

Well 31/1-3 S was drilled to a vertical depth of 3558 metres below sea level and a measured depth of 3568 metres. The well was terminated in the Johansen Formation from the Early Jurassic.

Well 31/1-3 A was drilled to a vertical depth of 3368 metres below sea level and a measured depth of 3791 metres. The well was terminated in the Drake Formation.

Water depth at the site is 348 metres. The wells have been permanently plugged and abandoned.

The wells were drilled by the Transocean Spitsbergen drilling facility, which will now drill wildcat well 34/6-6 S in production licence 554 in the northern North Sea.

Updated: 09/02/2023