Delineation of the 7220/11-1 Alta oil and gas discovery

28. august 2017

Good news from the Barents Sea.

Idemitsu Petroleum Norge is pleased to announce that drilling and production testing of Alta appraisal well 7220/11-4 (Alta-4) and drilling of the sidetrack 7220/11-4 A have been successfully completed. The wellbores are located in PL 609 in the southern Barents Sea.

The Alta-4 well was drilled by the semi-submersible drilling rig Leiv Eiriksson approximately 2 km south of the original Alta discovery well 7220/11-1, some 2.5 km north-northeast of the previous appraisal wells 7220/11-3 and 7220/11-3 A and 190 kilometres northwest of Hammerfest. The main objectives of the well were to appraise the east flank of the Alta discovery further and to provide a calibration point for the planning of a possible future horizontal well for an extended well test.

The well encountered a gross hydrocarbon column of 48 metres, comprising 4 metres of gas and 44 metres of oil in a sequence of Permo-Triassic clastic carbonate sediments. Extensive data acquisition and sampling was carried out in the reservoir, including conventional coring and fluid sampling. Pressure data show the same fluid contacts and gradients as observed in previous wells drilled on the Alta discovery, confirming good communication across the large Alta structure.

A production test was performed in the oil zone, producing at a stabilised rate of 590 Sm3 of oil and 93 000 Sm3 associated gas per day on a 56/64” choke. The test confirmed very good reservoir properties and good lateral continuity within the Permo-Triassic clastic reservoirs. Well 7220/11-4 was drilled to a vertical depth of 2255 meters below sea level and terminated in Carboniferous rocks of the Ugle Formation.


A geological sidetrack (7220/11-4 A) was then drilled some 0.9 km towards the north. The sidetrack wellbore encountered a 54-metre hydrocarbon column in Upper Permian to Lower Triassic conglomerates and carbonate rocks in the Ørn Formation, of which 44 metres was an oil column. Reservoir quality varied across the oil column, including several zones with very good permeability. This sidetrack also confirmed the hydrocarbon contacts seen in the main wellbore. 7220/11-4 A was drilled to a vertical depth of 2027 meters below sea level and terminated in Carboniferous rocks of the Falk Formation. Extensive data acquisition including coring was carried out.

Hiroshi Arikawa, Managing Director of Idemitsu Petroleum Norge comments:
“I am delighted with the results from Alta-4 and -4 A. The reservoir connectivity, excellent properties and productivity demonstrated by the wellbores increases our hope for a commercial development of the Alta discovery.”

Idemitsu Petroleum Norge holds a 30 % working interest in
PL 609, which was awarded in the 21st licensing round in 2011. The license is operated by Lundin Norway with a 40 % working interest. The remaining 30 % interest is held by DEA Norge.


The NPD press release may be found here:


Idemitsu Petroleum Norge has a license portfolio focusing on the Barents Sea and Northern North Sea with ten producing assets in the Snorre and Fram field areas, in addition to being the second largest owner in the Knarr field. Idemitsu Petroleum Norge also holds material shares in promising discoveries such as Alta, Wisting/Hansen, Cara and Peon. Being present on the Norwegian Continental Shelf for nearly three decades, Idemitsu also participates in petroleum activities offshore the United Kingdom and Vietnam as partner and operator.