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Exploration wellbore: 33/9-10

General information

Wellbore history

General

Wildcat well 33/9-10 is located on the Tampen Spur North of the Murchinson Field. The Middle Jurassic Brent sand was the primary objective with the Lower Jurassic Statfjord sand as a secondary objective. Planned TD was 3695 m, interpreted to be 30 m into the Statfjord Formation.

Operations and results

Wildcat well 33/9-10 was spudded with the semi-submersible installation Fernstar on 7 April 1978 and drilled to TD at 3715 m in the Eraly Jurassic Statfjord Formation. Part of the well bore was drilled with oil-based mud.

The electric log pick of the top of the Early Cretaceous Cromer Knoll Group was taken at 3113 m, giving an Early Cretaceous thickness of 146.8 m. Lithologically, the Early Cretaceous consisted of 20.3 m of Barremian limestone at the base with red marl interbedded with the overlying claystone section.

Top Late Jurassic Viking Group was picked at 3259.8 m, 15.7 m high to prognosis. The thickness was 88.2 m of which the upper 69.2 m was the Draupne Formation and the lower 19 m was the Heather Formation. The lithology of the Viking Group was grey to dark grey, silty claystone.

The primary objective Brent Group was penetrated at 3348 m, 37.5 m high to prognosis. The sandstone was argillaceous, medium grained, and had fair to poor porosity. Of the expected 140 m of Brent Group, only 67.5 m was found. Of this 37 m was net sand. The Brent Group was water bearing. No shows were seen in the ditch samples. One core was cut from 3358 m to 3376 m. Very poor shows were observed in the core, but electric logs and Schlumberger Coriband analysis indicated the Brent Formation to be water wet. The shows in the core most likely came from flushing of the core with diesel and protectomagic mud. No residual oil was measured in the core plugs.

Top Dunlin Group was found at 3415.5 m, 110 m high to prognosis. It was 84.5 m thick versus the prognosed 140 m.

The secondary objective Statfjord Formation came in at 3500 m, 165.5 m high to prognosis. The Statfjord sands were tight with calcareous cement. Electric logs and lack of shows proved the formation to be water wet. Drilling went on in order to reach and identify the seismic reflector originally mapped as the Near Top Statfjord event. From 3635 m to TD there was a total of 20 m of very calcareous sandstone stringers that appeared to account for this reflector. The well was permanently abandoned as a dry well on 12 June 1978.

Testing

No drill stem test was performed

Cuttings available at the NPD

Interval [m]: 280.00 - 3713.00

Cores available at the NPD

Core length [m]: 18.00

Scanned core photos

3358-3360m	3360-3363m	3363-3366m	3366-3369m	3368-3371m
3371-3374m	3374-3376m

Palynological slides available at the NPD

No palynological slides in this wellbore.

Oil samples available at the NPD

No oil samples available.

Casing and leak-off tests

Mud

Drill stem test

No drill stem test in this wellbore.

Available logs

Lithostratigraphy

Composite log

Composite log (Format:PDF. Size: 0.496 Mb)
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Geochemical information

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Documents reported by the licencees (period for duty of secrecy expired)

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Old NPD WDSS reports, NPD papers and other related documents

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