Transocean Norge; Source: Transocean

Wintershall Dea’s appraisal well corroborates size of oil & gas discoveries, pushing them closer to development stage

Wintershall Dea Norge, a subsidiary of Germany’s oil and gas company Wintershall Dea, has completed the drilling of an appraisal well in the Norwegian Sea, using one of Transocean’s semi-submersible rigs.

Transocean Norge; Source: Transocean

The Norwegian Petroleum Directorate (NPD) granted Wintershall Dea Norge a drilling permit in September 2023 for the appraisal well 6406/3-12 S in production license 836 S, which was awarded on February 5, 2016, and is valid until February 5, 2026. This is the third well in this license, which was awarded in the Awards in Predefined Areas (APA) in 2015. Wintershall Dea holds an ownership interest of 40% and acts as the operator of the license, while its partners are Equinor (30%) and DNO Norge (30%).

According to the NPD, this appraisal well on the Bergknapp discovery has confirmed the earlier 6406/3-10 oil discovery as well as the 6406/3-10 A gas discovery in the Norwegian Sea, 200 kilometers north of Kristiansund. While the Bergknapp oil discovery was proven in reservoir rocks from the Middle Jurassic (Garn Formation) and the Early Jurassic (Tilje Formation) in 2020, the gas discovery was proven in reservoir rocks from the Early Jurassic (Åre Formation) in 2021.

Prior to the drilling of the well 6406/3-12 S, the operator’s resource estimate for the oil discovery was between 6.4-13.3 million Sm3 of recoverable oil equivalent, and between 2-9 million Sm3 of recoverable oil equivalent for the gas discovery. While the primary exploration target for the well was to investigate the development of the reservoir and reservoir quality in the Tilje Formation in 6406/3-10, the secondary target was to delineate the 6406/3-10 A gas discovery.

Furthermore, the appraisal well 6406/3-12 S encountered a 59-meter oil column in the Ile Formation, in sandstone layers totaling around 33 meters with poor to moderate reservoir quality. While the oil/water contact was not encountered, an oil column of about 146 meters was encountered in the Tilje Formation in sandstone layers totaling about 77 meters with poor to good reservoir quality.

In addition, the appraisal well encountered a 108-meter oil column in the upper part of the Åre Formation in sandstone layers totaling around 28 meters with poor to moderate reservoir quality. No oil/water contact was encountered. A 56-meter gas column was encountered in the lower part of the Åre Formation in sandstone layers of around 15 meters with poor reservoir quality, but the gas/water contact was not proven.

As the appraisal well confirms the size of the oil discovery, the current estimate is between 7-12 million Sm3 of recoverable oil equivalent (44-75 million barrels), however, the gas discovery estimate is somewhat reduced to 1-4 million Sm3. The licensees are expected to now consider connecting both discoveries to existing infrastructure in the area. The well was drilled using the Transocean Norge rig, thanks to a 17-well contract, which the rig secured in September 2022.

Moreover, the well was not formation-tested, but extensive data acquisition and sampling have been carried out. The appraisal well was drilled to a vertical depth of 4,729 meters below sea level and was terminated in the Åre Formation from the Early Jurassic. The water depth at the site is 308 meters and the well has been permanently plugged and abandoned.

The Transocean Norge sixth-generation Moss Maritime CS60 semi-submersible rig was constructed at Jurong Shipyard in Singapore. It can accommodate 150 people and its maximum drilling depth is 40,000 ft. Transocean recently got a one-well extension with Wintershall Dea for the rig.