1/3-10 A

Exploration · Appraisal · P&A · Oil/gas · DONG E&P Norge AS · Oselvar · PL 274

1/3-10 A is an appraisal exploration wellbore in the North Sea, drilled by DONG E&P Norge AS, entered Jan 7, 2008, to 3,632 m in the Sele Fm.

Discovery 1/3-6 Oselvar · On the map →

3,632: m total depth · 3,335 m vertical
72: m water depth
Jan 7, 2008: entered · completed Feb 13, 2008
Sele Fm: at total depth · Paleocene
—: m of core
145: °C bottom-hole temperature

SODIR FACTPAGES · RECORD UPDATED NOV 4, 2026 · RELEASED FEB 13, 2010

On file for this wellbore

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

Drilling

Drilling facility: MÆRSK GUARDIAN · Jack-up 3 legs
Drilling days: 38
Kelly bushing elevation: 45 m
Maximum inclination: 53.79999924°
Drilling permit: 1168-L
Licensing round: NST2001
Plugged and abandoned: —
Core samples available: Yes
Cuttings samples available: Yes
Position · ED50: 56.92774° N, 2.70575° E
Hydrocarbons in: Forties Fm · Paleocene

Well history

WRITTEN BY THE NORWEGIAN OFFSHORE DIRECTORATE

General

Well 1/3-10 A is located on the Hidra High, ca 20 km south-south west of the Ula Field in the North Sea. It was drilled to further appraise the Forties Formation Sandstone in the Oselvar structure, after the primary well 1/3-10 had confirmed oil and gas in the structure. The main goal of the sidetrack well was to penetrate the water leg for water sampling and establish the free water level in the structure.

Operations and results

The Oselvar 1/3-10 A appraisal sidetrack kicked off in the claystones of the Hordaland Group at 2276 m on 7 January 2008. It was drilled with the jack-up installation Mærsk Guardian to final TD at 3632 m in the lower part of the Sele Formation below the target Forties Sandstone. The well was drilled without significant technical problems. It was drilled with Carbo SEA OBM from kick-off to TD.

The well track penetrated the remaining Hordaland claystone, and the claystones, tuffaceous claystones and sandstones of the Rogaland Group (Paleocene-Eocene), which included the Balder Formation, the Sele Formation, and the target Forties Sandstone Member. The top of the Balder Formation came in only 1 m TVD shallow compared to prognosis, the Sele Formation came in deep (10 m TVD) compared to prognosis. The Forties Sandstone came in at 3516 m (3257 m TVD RKB), 11 m TVD compared to prognosis. The log data confirmed that the well had penetrated the water leg of the reservoir as expected, and indicated 64 m MD (43 m TVD) gross reservoir and a net reservoir of 37 m MD (25 m TVD), giving a Net/Gross of 0.58. The net reservoir, all of which is considered to be non-pay, has an average porosity of 18 % and mobilities in the range 1-13 mD/cP. Pressure measurements indicated a free water level at 3245 m TVD 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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