35/11-23 A

General

Well 35/11-23 A is a geological side-track to the 35/11-23 Echino discovery on the Lomre Terrace north of the Troll Field in the North Sea. Well 35/11-23 discovered oil and gas in the Late Jurassic Sognefjord Formation and the Middle Jurassic Brent Group. The 35/11-23 A side-track was drilled down flanks to the west of the main bore on the Echino structure and the objective was to establish the OWC within the Sognefjord J56 reservoir.

Operations and results

Appraisal well 35/11-23 A was kicked off from the main bore at 1130 m on 7 November 2019. It was drilled with the semi-submersible installation Deepsea Atlantic to TD at 2883 m in the Middle Jurassic Heather Formation. Operations proceeded without significant problems. The well was drilled with Synteq oil-based mud from kick-off to TD.

The J56 and J52 Sognefjord Formation sands that were found hydrocarbon bearing in the main bore, were penetrated from 2551 to 2605 m (2344 to 2395 m TVD) and from 2634 to 2673 m (2422 to 2460 m TVD), respectively. Both had good reservoir properties and were water bearing. Combined pressure data from the main bore and the side-track proved an OWC in the J56 sand at 2544 m (2337 m TVD). Pressure data also showed 3 bar lower pressure in J56 than in J52. The Krossfjord Formation from 2798 to 2808 m (2578 to 2588 m TVD) had a thin sand with high resistivity and shows described with direct and cut fluorescence. These are the only shows described in the well.

No conventional cores were cut, but sidewall cores were taken. RCX water samples were taken at 2552.2 m .

The well was permanently abandoned on 21 November 2019 as a dry appraisal w