Oil and gas discovery in the North Sea (35/11-30 S and 35/11-30 A)

Preliminary estimates indicate the size of the discovery is between 2.0-4.5 million standard cubic metres (Sm3) of recoverable oil equivalent. This corresponds to between 12.6 and 28.3 million barrels.

The drilling operation was carried out by the Deepsea Atlantic rig. These were exploration wells number 22 and 23 in production licence 090, awarded in the eighth licensing round in 1984.

There has been significant exploration activity in this area in recent years. Several discoveries have been made in what are referred to as the Fram licences, as well as in surrounding production licences.

The licensees are considering tying the Rhombi discovery to future or existing infrastructure in the area.

The Fram axis (Fram, Fram-H-Nord, Byrding) is routed to the Troll C platform for processing and export.

Geological information:

The objective of the well was to prove petroleum in Upper Jurassic reservoir rocks in the Sognefjord Formation. The secondary exploration target was to prove petroleum in Middle Jurassic reservoir rocks in the Fensfjord Formation.

Well 35/11-30 S encountered a 41-metre gas-filled sandstone layer and a 9-metre aquiferous sandstone layer in the Sognefjord Formation, both of which with very good reservoir properties. The gas/water contact was not encountered.

In the secondary exploration target, well 35/11-30 S encountered a 72-metre sandstone layer with very good reservoir properties in the Fensfjord Formation. The reservoir was aquiferous.

Well 35/11-30 A proved a 43-metre gas column over a 6-metre oil column in the Sognefjord Formation. The reservoir was 110 metres thick, with very good reservoir properties. The gas/oil contact was encountered at 1961 metres and the oil/water contact at a vertical depth of 1967 metres below sea level.

In the secondary exploration target, well 35/11-30 A encountered a 12-metre oil column in a 100-metre sandstone reservoir in the Fensfjord Formation, with good reservoir properties. The remaining 88 metres were aquiferous. The oil/water contact was not encountered.

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

Well 35/11-30 S was drilled to a vertical depth of 2232 metres and measured depth of 2358 metres below sea level. Well 35/11-30 A was drilled to a vertical depth of 2266 metres and measured depth of 2650 metres below sea level. Both wells were terminated in the Heather Formation in the Middle Jurassic.

Water depth at the site is 355 metres. The wells have been permanently plugged and abandoned.