1/3-1 is a wildcat exploration wellbore in the North Sea, drilled by A/S Norske Shell, entered Jul 6, 1968, to 4,877 m in the Zechstein Gp.
Discovery 1/3-1 · On the map →
- 4,877
- m total depth
- 71
- m water depth
- Jul 6, 1968
- entered · completed Nov 11, 1968
- Zechstein Gp
- at total depth · Late Permian
- 19.2
- m of core in 1 core
- 182
- °C bottom-hole temperature
SODIR FACTPAGES · RECORD UPDATED FEB 20, 2026 · RELEASED NOV 11, 1970
On file for this wellbore
What the Directorate holds from this wellbore. Each opens the section that lists it.
Drilling
- Drilling facility
- ORION · Jack-up 3 legs
- Drilling days
- 129
- Kelly bushing elevation
- 26 m
- Maximum inclination
- 18°
- Drilling permit
- 15-L
- Licensing round
- 1-A
- Plugged and abandoned
- —
- Core samples available
- Yes
- Cuttings samples available
- No
- Position · ED50
- 56.85583° N, 2.85139° E
- Hydrocarbons in
- Tor Fm · Late Cretaceous
- Hydrocarbons in
- Cromer Knoll Gp · Early Cretaceous
Well history
WRITTEN BY THE NORWEGIAN OFFSHORE DIRECTORATE
General
Well 1/3-1 was drilled on the crest of a salt-induced anticline on the Hidra High in the North Sea. The purpose of the well was to investigate Tertiary and Mesozoic sequences down to top salt.
The well is Type Well for the Våle, Hidra, Hod, and Tor Formations, and Reference Well for the Vidar, Ekofisk and Blodøks Formations.
Operations and results
Well 1/3-1 was spudded with the four leg jack-up installation Orion on 6 July 1968 and drilled to TD at 4877 m in the Permian Zechstein Group. From the deviation survey it is seen that the well starts to deviate significantly at 4037 m (8 deg deviation), and at TD the deviation is 18 deg. This will correspond to a TVD RKB that is ca 25 m less than MD RKB.Several drilling problems occurred during the drilling operations of well 1/3-1. While drilling the 17 1/2" hole for the 20" casing, circulation losses started at 220 m (720') and became total at 238 m (781'). While drilling on with sea water, without returns, the pipe stuck. The lost circulation zone eventually had to be sealed off with a cement plug. In the Tertiary plastic clays the problems included tight hole conditions, bit balling, and difficulties in lowering the logging tools. The mud weight had to be raised from 10.8 ppg to 13.6 ppg to stabilize the hole. At 4131 m (13554') the bit twisted off, but was retrieved on the second fishing run. A hydrocarbon bearing zone was encountered at 4567 m (14984'). The mud became gas cut. At 4592 m (15064') the degasser was overloaded and the circulation lost, probably higher in the hole. A cement plug was needed to combat the lost circulation problems. It was then decided to set a 7" casing. Circulation was lost while running the casing, which had
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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