6604/6-1

General

Well 6604/6-1 was drilled to test the Gullstjerne prospect ca 14 km east of the 6604/5-1 Balderbrå discovery on the Vigrid Syncline in deep waters in the Norwegian Sea. The primary objective was to confirm live hydrocarbons in the Late Cretaceous Springar Formation submarine fan systems.

Operations and results

Wildcat well 6604/6-1 was spudded with the semi-submersible installation Scarabeo 8 on 1 December 2019 and drilled to TD at 3640 m in the Late Cretaceous Springar Formation. Operations proceeded without significant problems, although adverse weather led to as much as 22.3 days (45.5%) of the rig time. The well was drilled with seawater and hi-vis pills down to 2200 m, with Innovert NS oil-based mud from 2200 m to 2318 m and with water-based DW/HT mud from 2318 m to TD.

The Springar Formation came in at 3084 m. It is composed of mudstones with two sandstone units Sandstone 2 with top at 3306 m and Sandstone 3 with top at 3452 m. The sands are separated by a ca 65 m thick claystone unit. The Sandstone 2 unit was finely laminated and had poor permeability and only residual gas saturation, but good porosity - up to 30 %. The Sandstone 3 unit consisted of two separate sandstone packages with poor permeability. The upper one was more laminated with porosities up to 22 % and the lower one was less laminated with porosities up to 24 %. A common water gradient was observed from pressure measurements in sandstone units 2 and 3. The well was dry with no shows.

No cores were cut. MDT fluid samples were taken at 3322 m, 3463.5 m, and 3529.4 m. All samplings recovered formation water, mud filtrate and a little gas. The only temperatures available from the well are those from MDT samp