31/2-20 S

Exploration · Wildcat · P&A · Oil/gas · Norsk Hydro Produksjon AS · Troll · PL 054

31/2-20 S is a wildcat exploration wellbore in the North Sea, drilled by Norsk Hydro Produksjon AS, entered Nov 27, 2002, to 3,400 m in the Brent Gp.

Discovery 31/2-1 (Troll Vest) · On the map →

3,400: m total depth · 1,928 m vertical
332: m water depth
Nov 27, 2002: entered · completed Dec 8, 2002
Brent Gp: at total depth · Middle Jurassic
—: m of core
72: °C bottom-hole temperature

SODIR FACTPAGES · RECORD UPDATED FEB 20, 2026 · RELEASED DEC 8, 2004

On file for this wellbore

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

Drilling

Drilling facility: POLAR PIONEER · Semisub steel
Drilling days: 9
Kelly bushing elevation: 23 m
Maximum inclination: 66.5°
Drilling permit: 1045-L
Licensing round: 4
Plugged and abandoned: —
Core samples available: No
Cuttings samples available: No
Position · ED50: 60.79981° N, 3.44936° E
Hydrocarbons in: Sognefjord Fm · Late Jurassic

Well history

WRITTEN BY THE NORWEGIAN OFFSHORE DIRECTORATE

General

Well 31/2-20 S was drilled from the Troll B platform as a joint Pl054 and Pl191 activity. The objective was to investigate the Hydrocarbon-potential in the "P/Q"-prospect shortly west of the Troll West oil province. The main objective was the middle Jurassic Brent Group. A structural closure in the Late Jurassic Fensfjord formation was a secondary target.

Operations and results

Exploration well 31/2-20 S was kicked off on 27 November 2002 from the 13 3/8" casing at 2447/1468 m MD/TVD RKB in production well 31/2-E-3H/AY1H/AY2H/AY3H on the Troll B platform. It was drilled to TD at 3400/1928 m MD/TVD RKB in the Brent group without significant problems. It was drilled as an 8 1/2 " hole from kick-off to TD using a KCl/polymer mud. The main results were:

The P/Q prospect was found to be dry. No hydrocarbon shows were observed in the Brent Group

The Sognefjord Formation sandstones were encountered with oil and gas according to prognosis (GOC and OWC were met at 2695 m/1545.5 m MD/TVD MSL and 2759.2 m/1572 m MD/TVD MSL respectively). No other contacts were observed.

Top Brent was penetrated 39 m deeper than expected ? basically due to higher than expected Jurassic interval velocities. A hydrocarbon fluid-inclusion study performed concludes: No fluorescent hydrocarbon fluid inclusions are observed, either in cemented fractures or in quartz overgrowth, which confirm low probability of any petroleum charging during geologic time.

The well was drilled with return to seabed from seafloor 355m to setting depth of 15 5/8" casing at 1146m. MWD was run through the whole well. In the interval 2457-3400m MD RKB an LWD-suite comprising GR, resistivity, density, neutron, and sonic logs was run. No wire line survey was run. No cores were taken. No biostratigraphic evaluation has been performed. No fluid samples were taken.

The well was permanently abandoned on 8 December. Oil and ga

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.

Developers: this page as JSON is GET /v1/data/norway/wells/4636, documented in the API reference.