35/11-20 A

Exploration · Appraisal · P&A · Oil · Wintershall Norge AS · PL 248 F

35/11-20 A is an appraisal exploration wellbore in the North Sea, drilled by Wintershall Norge AS, entered Jul 14, 2016, to 3,973 m in the Heather Fm.

Discovery 35/11-20 S (Orion) · On the map →

3,973: m total depth · 3,319 m vertical
373: m water depth
Jul 14, 2016: entered · completed Aug 7, 2016
Heather Fm: at total depth · Middle Jurassic
103.2: m of core in 2 cores
—: °C bottom-hole temperature

SODIR FACTPAGES · RECORD UPDATED FEB 20, 2026 · RELEASED AUG 7, 2018

On file for this wellbore

What the Directorate holds from this wellbore. Each opens the section that lists it.

Drilling

Drilling facility: BORGLAND DOLPHIN · Semisub steel
Drilling days: 24
Kelly bushing elevation: 31 m
Maximum inclination: 56.79999924°
Drilling permit: 1633-L
Licensing round: NST99
Plugged and abandoned: —
Core samples available: Yes
Cuttings samples available: Yes
Position · ED50: 61.22230° N, 3.44044° E
Hydrocarbons in: Intra Heather Fm Ss · Late Jurassic

Well history

WRITTEN BY THE NORWEGIAN OFFSHORE DIRECTORATE

Wellbore history

General

Well 35/11-20 A is a geological sidetrack to the 35/11-20 S Antares well, which discovered oil in Oxfordian age Intra-Heather Formation sandstone. The sidetrack was planned to appraise the presence of HC-filled Upper Jurassic Early-Middle Oxfordian sandstone (Orion prospect) with appropriate thickness and quality to be commercially exploited. Secondary target was to prove the presence of HC-filled Brent and Cook formations.

Operations and results

Appraisal well 35/11-20 A was kicked off from the main bore (35/11-20S) at 1815 m in the Shetland Group on 14 July 2016. It was drilled with the semi-submersible installation Borgland Dolphin. Drilling operations proceeded without significant problems, but intermediate logging of the Orion reservoir was aborted as the cable broke at surface and was lost in hole. Fishing was unsuccessful and it was decided to plug back and sidetrack to reach the secondary objective. Final TD for well 35/11-20 A became 3973 m (3319 m TVD) m in Callovian age sediments in the Heather Formation. The well was drilled with Innovert oil based mud from kick-off to TD.

35/11-20A encountered top primary target Oxfordian sandstone at 3869 m (3233 m TVD). The reservoir was 27 m TVD thick, which is thinner than in the main bore, but had much better reservoir quality, characterized by an average porosity of 18% and 64% Net-to-Gross. The top 8 m TVD were found oil bearing with a possible OWC at around 3878 m (3241 m TVD).

Two cores were cut: core 1 from 3870 to 3898.5 m and core 2 from 3898.5 m to 3973 m. Core recoveries were 99% and 100%. The MDT tool was r

Around this wellbore

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About this data

Norwegian Offshore Directorate (Sodir) FactPages, mirrored nightly and used under the Norwegian Licence for Open Government Data (NLOD). Depths are metres along the wellbore from the kelly bushing unless a row gives its own unit; older cores are filed in feet. A zero the Directorate files for an unmeasured pressure, density, or temperature is shown as a dash.

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