Relinquishment Report for Licence P1301 (Block 12/17b)
Licence Information
Licence Number
Licence Round
Licence Type
Block Number (s)
Operator
Partners
Work Programme /
Status
P1301
23rd Round
Traditional Production Licence
12/17b
Lundin Heather Ltd (30%)
Revus Energy UK Ltd (35%)
Britcana Energy Limited (35%)
12/17b-1 was drilled to 5678’ MDRTE (2385 m
MDRTE); fulfilling the Drill or Drop commitment
depth of 2135m / P&A.
Fig 1: Block 12/17b Relinquishment Area Map
Block 12/17b is bounded by straight lines joining the following coordinates:
1)
2)
3)
4)
5)
58° 25’ 00.000” N
58° 25’ 00.000” N
58° 20’ 00.000” N
58° 20’ 00.000” N
58° 25’ 00.000” N
2° 44’ 00.000” W
2° 36’ 00.000” W
2° 36’ 00.000” W
2° 44’ 00.000” W
2° 44’ 00.000” W
These coordinates are specified using the “European Datum 1950”.
Licence Work Programme Summary
P1301 was awarded for a 4 year term, from 22 December 2005, with a 2+2 year drill or drop
option. Having committed to drill a well and subsequently drilled dry well 12/17b-1, the
P1301 partnership has elected to relinquish the block early.
Exploration Activity
Two superimposed objectives, collectively termed “Ridgewood”, were selected for drilling
by the P1301 partnership. The exploration programme was designed to test a tilted fault
structure and the primary target was Jurassic sands of Volgian age. A secondary, deeper
objective was the deeper Middle Jurassic Beatrice sands of Callovian age.
The Ridgewood prospect is located in the Caithness Basin in the Inner Moray Firth, some 15
miles east of Wick (See fig 1). Beatrice is the closest producing field, which produces from
the Callovian Beatrice sandstone (shallow marine facies). In addition there are several
smaller discoveries and wells with oil shows in the area.
The closest offset wells are 12/16-1, 12/16-2, 12/18-1 and 12/22-3. These wells were
plugged and abandoned as dry holes, although the 12/18-1 well encountered massive water
bearing sandstones. Note: The 12/18-1 well was deviated up to 50 deg.
Ridgewood is interpreted as a four way dip fault related roll over structure (See fig 2) with
the maximum closure, at Volgian level in Upper Jurassic, measured as 1236 acres. The
Volgian sandstone was deposited as turbidites from a provenance area to the north and
potential reservoir sand is related to strong amplitudes. The prospect has a bounding fault
dipping to the south-west and a vertical well was designed to cross this fault at a depth of
2046’ MD BRT (-1896ft TVDss). Analysis of the digital data from the site survey
interpreted that no drilling hazard is related to this fault.
Fig 2: Ridgewood Volgian Structure Map
The structure is related to a post depositional inversion of an Upper Jurassic EW oriented
basin (See fig 3). The structure reduces in size towards the base of the Upper Jurassic
sequence and at the Beatrice level it depends on up dip fault seal. The Beatrice Sandstone is
a shallow marine to deltaic facies and the source rock is assumed to be Devonian
formation(s).
Fig 3: Block 12/17b Location on Regional Structure Map
Seismic Interpretation
The prospect was depth converted (See Fig 4) using stacking velocities and well 12/22-3 for
correlation. There are large lateral velocity changes in the Lower Cretaceous overburden that
introduce uncertainties in the depth prognosis. The structure is however defined on good
quality 2D seismic data and the coverage was sufficient to define a drillable structure and
position a well.
Fig 4: 2D Seismic line over the Ridgewood Prospect
Drilling Summary
Operations on 12/17b-1 with the GlobalSanta Fe Galaxy 2 jack up rig commenced 18
December 2007. The definitive final location was
Latitude:
Longitude:
RTE-MSL
RTE-seabed
58° 23’ 51.609” N
02° 38’ 15.811” W
153ft, Water depth
356ft, Leg Penetrations
6 473 190.27m
521 176.84m
203ft,
6ft
The well was spudded at 03.00 hours 21 December 2007.
36” x 26” hole was drilled to 602ft (246ft bml) and the 30" conductor was set and cemented
at 597ft (241ft bml). 17.1/2" hole section was drilled near vertically to 2478 ft MD and 133/8" casing was run and set at 2459 ft MD. 12-1/4" hole was drilled near vertically to 5,678
ft MDRTE reaching TD with an average ROP of 17.4ft/hr on 04 January 2008.
P&A of the well commenced at was completed at 14.30 hrs 07 January 2008.
G&G Results
The Ridgewood structure was dry; the reason for failure is interpreted to be the absence of a
sealing mechanism. Water Saturations within the 1600ft objective interval were reported at
94% with a net to gross of 43% and 18.5% porosity.
Prospectivity & lead
Remaining hydrocarbon potential has been identified in the deeper Callovian prospect. This
prospect was considered uneconomic unless the shallower Volgian sand proved to be
hydrocarbon bearing. In the absence of a Volgian hydrocarbon column the well was plugged
and abandoned as a dry hole, without drilling to the Callovian secondary objective.
Clearance
P1301 partners give approval to BERR to publish material contained within this report.