7220/11-3 A

General

Well 7220/11-3 A is a geological sidetrack to well 7220/11-3, which confirmed oil and gas in Triassic conglomerates and Permian carbonates in a central position on the Alta discovery. The Alta structure lie on the southern Loppa High in the Barents Sea. Well 7220/11-3 did not penetrated to the oil-water contact. The primary objective of the sidetrack was to prove the presence and thickness of the Early Triassic conglomerates ca 400 m to the east of the main wellbore and to confirm hydrocarbon columns and fluid contacts similar to those established in the 7220/11-1 discovery well.

Operations and results

Appraisal well 7220/11-3 A was kicked off from 1105 m in the 7220/11-3 main bore on 2 September 2015. It was drilled with the semi-submersible installation Island Innovator to 1240 m where it was aborted due to steering problems. The wellbore was plugged back and successfully sidetracked. It was drilled with no significant further issues to a total depth of 2135 m (1991.8 m TVD) in Permian carbonates of the Ørn Formation. The well was drilled with AquaDrill mud from kick-off to TD.

The geological sidetrack proved a total hydrocarbon column height of 74 m comprising 30 m of gas over 44 m of oil. The column extended from 2013 m (1880 m TVD) in the upper Klappmyss Formation down to a free-water level estimated to be at 2094 m (1954 m TVD) in Early Triassic conglomerates. The gas-oil contact was established at 2046 m (1910 m TVD). The pressures and gradients were found to be comparable with those established in the 7220/11-3 main well and in the 7220/11-1 discovery well. Numerous oil shows were described in siltstones and sandstones below 1100 m in the Snadd and Kobbe formations. Shows were described also below the hydrocarbon-bearin