Delineation of the 25/8-19 S (Iving) oil and gas discovery near the Balder field in the North Sea - 25/8-21 S and 25/8-22 S

The wells were drilled about 8 kilometres northwest of 25/8-11 Ringhorne on the Balder field in the North Sea, about 200 kilometres west of Stavanger.

The 25/8-19 S (Iving) discovery was proven in 2019 in reservoir rocks from the Palaeocene (Heimdal Formation), the Early Jurassic (Statfjord Group), the Late Triassic (Skagerrak Formation) and in basement rock.

Before appraisal wells 25/8-21 S and 25/8-22 S were drilled, the operator’s resource estimate for the discovery was between 2 and 11 million standard cubic metres (Sm3) of recoverable oil equivalent in the Skagerrak formation.

The primary exploration target for well 25/8-21 S was to encounter the oil/water contact in sandstones in the Skagerrak Formation. The secondary exploration target was to evaluate the petroleum potential in the basement rock reservoir.

Well 25/8-21 S encountered a 3-metre gas column over an approximate 30-metre oil column in sandstones of poor to good reservoir quality in the Skagerrak Formation.

Oil was also encountered in a 6-metre sandstone layer with moderate reservoir quality in the lower part of the Skagerrak Formation. The oil/water contact was not encountered.

A separate oil column of about 50 metres was encountered in basement rock with poor reservoir quality. The oil/water contact was not encountered.

The primary exploration target for well 25/8-22 S was to evaluate the petroleum potential in sandstones in the lower part of the Statfjord Group and in the Skagerrak Formation.

The secondary exploration target was to evaluate the petroleum potential in the Heimdal Formation and basement rock.

Well 25/8-22 S encountered a 20-metre gas column over a 29-metre oil column in sandstones of moderate to good reservoir quality in the Skagerrak Formation.

Pressure data indicates communication in the Skagerrak reservoir between all wells in the discovery. The reservoir quality in the lowermost part of the Skagerrak Formation was not sufficient to confirm mobile petroleum. The oil/water contact was not encountered.

A 2-metre oil column was encountered in sandstone of good to very good reservoir quality in the lower part of the Statfjord Group, and this has been interpreted to be a separate accumulation in relation to 25/8-19 S (Iving). The oil/water contact was encountered at 2185 metres below sea level.

Well 25/8-22 S also encountered oil in thin sandstones in the upper part of the Statfjord Group (2 metres) and in the Heimdal Formation (3 metres).

The reservoir quality in basement rock was not sufficient to confirm mobile petroleum.

The results show that the appraisal wells will lead to a downward adjustment of the resource estimate in the Skagerrak Formation in 25/8-19 S (Iving), but it is still too early to give an updated estimate for the discovery.

The licensees will assess the results in the Skagerrak Formation in combination with other petroleum-bearing levels and discoveries in the area for further follow-up.

A small-scale formation test was conducted in the Skagerrak Formation in well 25/8-21 S. The formation test revealed limited flow properties. Well 25/8-22 S was not formation-tested, but data acquisition and sampling were carried out.

These are the third and fourth exploration wells in production licence 820 S. The licence was awarded in APA 2015.

Appraisal wells 25/8-21 S and 25/8-22 S were drilled to respective measured depths of 2663 and 2582 metres below sea level, and respective vertical depths of 2587 and 2515 metres below sea level. Both wells were terminated in basement rock.

Water depth at the site is 127 metres. The wells have been plugged and abandoned.

The wells were drilled by the Transocean Barents drilling facility, which will now proceed to Ølen.