Oil and gas discovery and dry well in the North Sea (33/12-N-3 HH and 33/12-N-3 GH)

Wildcat wells 33/12-N-3 HH and 33/12-N-3 GH were drilled in connection with drilling an oil development well on the Gullfaks Satellites (33/12-N-3 IH) in production licence 152.

The discovery was made in 33/12-N-3 HH in production licence 277, which was awarded in 2002 (North Sea Awards 2001). This is the first exploration well in this production licence.
Wildcat well 33/12-N-3 GH, which had drilling targets in production licence 152, was dry. Production licence 152 was awarded in 1988, in the 12th licensing round on the Norwegian continental shelf (NCS).

Preliminary estimates place the "Granat" discovery between 0.2 and 0.6 million standard cubic metres (Sm3) of recoverable oil equivalent (o.e.). This corresponds to 1.3 - 3.8 million barrels of o.e.

The licensees – Equinor (operator), Petoro and OMV – are considering tying the discovery back to existing infrastructure in the Gullfaks area.

The wells were drilled from production licence 050 using the Askeladden rig.

Geological information

The objective of wellbore 33/12-N-3 GH (N2A) was to prove hydrocarbons in reservoir rocks in the Tarbert Formation, with secondary targets in the Ness and Etive formations, all in the Brent Group from the Middle Jurassic.

The well encountered the Tarbert Formation in a total of 115 metres with 48 metres of sandstone layers with moderate to good reservoir properties and a total of 59 metres in the Ness Formation with 10 metres of sandstone layers with good reservoir properties. Both formations were aquiferous. Data was collected, including pressure data.

Wellbore 33/12-N-3 GH was drilled to respective measured and vertical depths of 6708 and 3460 metres, and was terminated in the Ness Formation.

The objective of wellbore 33/12-N-3 HH was to prove hydrocarbons in reservoir rocks in the Tarbert Formation, with secondary targets in the Ness and Etive formations, all in the Brent Group from the Middle Jurassic.

Wellbore 33/12-N-3 HHT2 encountered a total of 153 metres in the Tarbert Formation with 58 metres of sandstone layers with moderate reservoir quality. The wellbore encountered a total of 162 metres in the Ness Formation with 47 metres of sandstone layers with moderate to good reservoir properties, and a total of 26 metres of sandstone layers in the Etive Formation with poor to moderate reservoir properties. The Tarbert Formation contained gas, while the Ness and Etive formations were filled with oil/condensate. The well encountered a hydrocarbon column totalling 240 metres. The oil/water contact was not encountered. Data was collected, including pressure data.

Wellbore 33/12-N-3 HH was plugged and abandoned after being drilled to a vertical depth of 3275 metres due to an unstable hole. Technical sidetrack 33/12-3 HHT2 was drilled to respective measured and vertical depths of 7846 and 3715 metres, and was terminated in the Drake Formation. 

Water depth at the site is 137 metres, and the wells have been permanently plugged and abandoned.