Lundin Norway has completed the drilling of Alta oil and gas discovery appraisal wells in the Barents Sea. The oil company will now reassess the resource estimate of the discovery based on results from the pair of appraisal wells.
The appraisal wells 7220/11-4 and 7220/11-4 A are located in production license 609 where Lundin is the operator with 40% interest. Lundin’s partners in the license are Idemitsu Petroleum Norge and DEA Norge with 30% interest each.
The wells were drilled about two kilometers south of the discovery well 7220/11-1, about three kilometers north-northeast of the appraisal wells 7220/11-3 and 7220/11-3 A and 190 kilometers northwest of Hammerfest.
The discovery was proven in carbonate rocks in the Gipsdalen group in October 2014. Before the 7220/11-4 and 7220/11-4 A wells were drilled, the operator’s resource estimate for the discovery was between 20 and 64 million Sm3 of recoverable oil equivalents, the Norwegian Petroleum Directorate (NPD) informed on Monday.
The directorate further said that the objective of well 7220/11-4 was to delineate the eastern flank of the discovery by investigating the reservoir extent of conglomerates of the Late Permian to Early Triassic Age, Late Carboniferous to Early Permian carbonate rocks (Ørn formation), hydrocarbon columns and the quality of Carboniferous reservoir rocks (Falk formation).
The objective of well 7220/11-4 A, was to delineate the discovery about one kilometre north of 7220/11-4, investigate the extent of Late Permian to Early Triassic conglomerates and the quality of Late Carboniferous to Early Permian carbonate rocks (Ørn formation).
The well 7220/11-4 encountered a 48-meter hydrocarbon column in Late Permian to Early Triassic conglomerates, of which 44 meters was an oil column.
The well 7220/11-4 A encountered a 54-meter hydrocarbon column in Late Permian to Early Triassic conglomerates and carbonate rocks in the Ørn formation, of which 44 meters was an oil column.
The reservoir quality through the oil column varied in both wells. Several zones have very good permeability. The hydrocarbon contacts were the same in both wells.
Extensive data acquisition and sampling have been carried out. Pressure data shows the same hydrocarbon contacts as observed in previous wells drilled on the discovery and confirms good communication over the Alta structure.
A formation test was conducted in well 7220/11-4. The maximum production rate was 960 Sm3 oil and 93000 Sm3 associated gas per flow day through a 56/64-inch nozzle opening. The test confirmed very good reservoir properties and good lateral continuity in the conglomerate reservoirs.
According to the NPD, the results from the appraisal wells are important with regard to the further work on mapping the eastern flank of the discovery. The resource estimate will be reassessed based on the results from the appraisal wells, the agency added.
These are the 10th and 11th exploration wells in production license 609, which was awarded in the 21st licensing round in 2011.
The appraisal wells 7220/11-4 and 7220/11-4 A were drilled to a vertical depth of 2255 and 2027 meters below the sea surface, respectively, and were terminated in Carboniferous rocks in the Ugle formation and Falk formation, respectively. Water depth at the site is 402 meters.
The wells were drilled by the Ocean Rig-owned semi-sub drilling rig Leiv Eiriksson, which will now proceed to drill wildcat well 7220/6-3 in the northern part of production license 609.