35/11-25 A

General

Well 35/11-25 A is a geological side-track to well 35/11-25 S. It was drilled on the Apodida prospect on the Lomre Terrace, North of the Troll Field in the North Sea. The primary objective of well 35/11-25 A was to prove petroleum in the Late Jurassic Etive Formation.

Operations and results

Wildcat well 35/11 25 A was kicked off from 1519.4 m in the main well on 15 May 2021. It was drilled with the semi-submersible installation DeepSea Atlantic to TD at 3741 m (3237.7 m TVD) m in the Middle Jurassic Oseberg Formation. The well is vertical down to kick-off and deviated with a sail angle of ca 43 from there to TD. Operations proceeded without significant problems. The well was drilled with CarboSea oil-based mud from kick-off to 2934 m and with Syn Tec oil-based mud from 2934 m to TD.

The Late Jurassic J56 and J52 sandstones within the Heather Formation were water filled as in the main well. While drilling top Etive Formation, LWD logs indicated presence of reservoir and hydrocarbons and it was decided to core. A 72 m core was recovered, before drilling continued into the Rannoch and Oseberg formations. About 55 metres of sandstone of moderate reservoir quality was penetrated in the Etive Formation. Wireline logging was performed after programme and proved water in the Etive Formation.

There were no shows observed in the overburden. In the target reservoir interval, there were consistent shows on cuttings and core from base Ness Formation and through the Etive, Rannoch and Oseberg formations. Most shows are described as: Fair odour, no oil stain, even bright yellowish direct fluorescence, slow cloudy streaming blueish white cut fluorescence, good blueish white residual fluoresce