New oil & gas discovery in North Sea with tie-back on the horizon
Norwegian state-owned energy giant Equinor has made a new commercial oil and gas discovery in the North Sea off Norway, using a Transocean-owned rig.
Equinor Energy has concluded the drilling of a wildcat well 31/1-3 S and an appraisal well 31/1-3 A in production license 923, where Equinor is the operator with an ownership interest of 40 per cent, while other licensees are DNO Norge, Petoro, and Wellesley Petroleum with a 20 per cent stake each, respectively. These are the third and fourth exploration wells in this license, which was awarded in APA 2017.
The Norwegian giant secured consent for exploration drilling in August 2022 and a drilling permit for this prospect, which is called Røver Sør, in July 2022. The wells were drilled using Transocean’s Transocean Spitsbergen semi-submersible rig. The water depth at the site is 348 metres. The wells were drilled about 10 kilometres northwest of the Troll field in the North Sea and 130 kilometres northwest of Bergen.
The Norwegian Petroleum Directorate (NPD) revealed on Thursday, 9 February 2023, that 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. On the other hand, 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.
According to NPD, the 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, approximately 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.
Based on NPD’s statement, 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 3,227 metres below sea level in the Oseberg Formation.
Furthermore, the well 31/1-3 A encountered an oil column of around 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 3,211 metres below sea level in the Ness Formation.
The preliminary estimates place the size of the discovery between 2.7 and 7.4 million Sm3 of recoverable oil equivalent and the licensees intend to consider tying the discovery into existing infrastructure in the Troll area. While the wells were not formation-tested, extensive data acquisition and sampling have been carried out.
The well 31/1-3 S was drilled to a vertical depth of 3,558 metres below sea level and a measured depth of 3,568 metres. This well was terminated in the Johansen Formation from the Early Jurassic. The well 31/1-3 A was drilled to a vertical depth of 3,368 metres below sea level and a measured depth of 3,791 metres. It was terminated in the Drake Formation. The wells have been permanently plugged and abandoned, outlined the Norwegian Petroleum Directorate.
The Transocean Spitsbergen rig will now drill a wildcat well 34/6-6 S in production license 554 in the northern North Sea.
Seventh discovery in this area since 2019
In a separate statement, Equinor highlights that the new oil and gas discovery close to the Troll field in the North Sea is the seventh discovery in this area since the autumn of 2019. According to preliminary estimates, the size of the discovery is between 17 and 47 million barrels of recoverable oil equivalent, of which the majority is oil, underlines the Norwegian giant.
Geir Sørtveit, Equinor’s senior vice president for exploration and production west operations, remarked: “Discoveries close to existing infrastructure are important to maintain oil and gas production from the Norwegian continental shelf. They need smaller volumes to be profitable and can be put on stream quickly with low carbon emissions. As this discovery is close to the Troll field and other discoveries we have made in the area, we can already now state that it will be commercial.”
The six discoveries that Equinor have made earlier in this area are Echino Sør (2019), Swisher (2020), Røver Nord (2021), Blasto (2021), Toppand (2022), and Kveikje (2022). The company says that there is uncertainty as to the size of the discoveries, but an average of the various estimates gives a total volume of around 350 million barrels of oil equivalent, corresponding to a medium-sized Norwegian oil or gas field, and the size of the Aasta Hansteen field in the Norwegian Sea.
“Equinor has started field development projects to coordinate the development of these discoveries by utilizing existing infrastructure in collaboration with our partners. This discovery will be part of this work,” says Sørtveit.
Equinor points out that the name of the next exploration well in this area is Heisenberg and the results of this well are to be ready in March. More exploration wells are planned in the area later this year. Equinor’s exploration strategy outlines that the firm will look for volumes in mature areas, where discoveries can be tied into existing infrastructure to maximise the value of investments made over 40 years.
The company intends to drill between 20 and 30 exploration wells each year moving forward with around 80 per cent of the exploration wells to be drilled in familiar areas near existing infrastructure, but certain new areas and ideas will also be tested.
Equinor states that it will drill wells based on three main criteria: high profitability and low break-even prices, short payback time and low carbon intensity, as exploration is “crucial in order to maintain the cash flow from the Norwegian continental shelf and to secure the gas volumes necessary to develop a blue hydrogen value chain.”