Aker BP, the operator of production licences 873, 873 B and 1249, has concluded its Omega Alfa exploration campaign in the area around Yggdrasil in the North Sea.
The campaign covers wellbores 25/1-14, 25/1-14 A, B, C, D, E, F and G. Yggdrasil is located about 180 kms from Bergen.
Discoveries were made in a total of four wellbores. The overall discovery volume is estimated at between 15.3 and 21.3 million standard cubic metres (Sm3) of oil equivalent (o.e.). This corresponds to between 96 and 134 million barrels of oil equivalent.
The licensees will assess the discoveries as part of their development of the Yggdrasil area.
The wellbores were drilled near the formerly producing fields Frigg and Øst Frigg. The objective of the wellbores was to prove and delineate remaining petroleum deposits in five prospects in the Frigg Formation.
The prospects ('Omega', 'Alfa', 'Alfa Sør', 'Sigma NE' and 'Pi') were drilled horizontally in order to map the thickness and extent of oil that has re-migrated from Frigg and Øst Frigg.
The investigation of re-migrated oil in the Yggdrasil area started in production licence 873 (awarded in APA 2016) with the drilling of 25/2-23 A & S in 2021/2022.
Further investigations in the licence took place through 25/2-24 S, A, B and C in 2023. 25/1-14, 25/1-14 A, B, C, D, E, F and G are the first wellbores in production licence 873 B (awarded in APA 2023) and production licence 1249 (awarded in APA 2024).
The wellbores were drilled by the Deepsea Stavanger installation. The rig is now headed for the Munin field, which is operated by Aker BP.
Geological information
The wellbores were drilled from production licence 873 B, and the horizontal wellbores extended into production licences 873 and 1249. 25/1-14, 25/1-14 A, B and C were classified as wildcat wellbores and 25/1-14 D, E, F and G were classified as appraisal wellbores. A total of four discoveries were made in five deposits. They were made in 'Omega', 'Alfa', 'Sigma NE', 'Pi', and 'Sigma' was also proven in 25/1-14 G. 'Alfa Sør' was dry.
25/1-14: The objective of 25/1-14 was to prove petroleum in the "Omega" prospect, which is located between the two shut-down fields Frigg and Øst Frigg. It encountered an 18-metre gas column and a 9.5-metre oil column in the Frigg Formation with very good to excellent reservoir quality.
25/1-14 A: The objective of 25/1-14 A was to prove hydrocarbons in the "Alfa" prospect, which is located about 5 kilometres northeast of 25/1-14. Its secondary objective was to delineate "Omega". The wellbore was drilled as a horizontal sidetrack from 25/1-14.
25/1-14 A encountered an oil column of up to 8 metres in "Alfa". The reservoir in the Frigg Formation is of very good to excellent reservoir quality. An oil column of up to 10 metres was also encountered in "Omega".
25/1-14 B: The objective of 25/1-14 B was to prove petroleum in "Alfa Sør", which is located about 5 kilometres east of "Omega". The wellbore was drilled as a horizontal sidetrack from 25/1-14 A.
25/1-14 B encountered thin sandstone layers with hydrocarbon shows in the Frigg Formation with very good to excellent reservoir quality. The wellbore is classified as dry.
25/1-14 C: The objective of 25/1-14 C was to prove petroleum in "Sigma NE" and "Pi", which are located 3 and 6 kilometres west of 25/1-14, respectively. Its secondary objective was to delineate "Omega". The wellbore was drilled as a horizontal sidetrack from 25/1-14.
25/1-14 C encountered an oil column of up to 14 metres in "Sigma NE" and up to 20 metres in "Pi" in the Frigg Formation with very good to excellent reservoir quality. It also encountered an oil column of up to 13 metres in "Omega".
25/1-14 D was drilled as a horizontal sidetrack from 25/1-14 A. It encountered an oil column of up to 11 metres in the easternmost part of "Alfa".
The northernmost part of "Omega" was delineated by 25/1-14 E. The wellbore was drilled as a horizontal sidetrack from 25/1-14 and encountered an oil column of up to 14 metres.
The objective of 25/1-14 F was to delineate the southwestern part of "Sigma NE", but the wellbore did not reach the planned TD.
25/1-14 G completed the delineation of the southwestern part of "Sigma NE" and encountered an oil column of up to 14 metres. It also proved "Sigma", which is located about 2 kilometres from "Sigma NE" and 5 kilometres from "Omega". The oil column proven in "Sigma" was up to 9 metres in the Frigg Formation, with very good to excellent reservoir quality. This wellbore has been reclassified as an appraisal wellbore.
Data acquisition was carried out in all wellbores, but 25/1-14 was subject to somewhat more extensive data acquisition and sampling.
25/1-14 was drilled to a vertical depth of 2220 metres below sea level, and was terminated in the Frigg Formation from the Eocene.
Water depth at the site is 112 metres. All wellbores will be plugged and abandoned.
Source: Norwegian Offshore Directorate
