EnCore Oil plc to provides an update on the Cladhan appraisal well 210/30a-4 located in UK North Sea Block 210/30a.
The appraisal well was drilled as a deviated well to a Total Measured Depth of 12,252 feet and encountered oil bearing Upper Jurassic sandstones in two separate reservoir intervals. No Oil Water Contact was observed. The Upper reservoir sequence had a gross True Vertical Thickness (TVT) of 18 feet and a net sand of 13 feet TVT.
The sand has an average porosity of 16 per cent. and hydrocarbon saturation of 82 per cent. Pressures suggest that this reservoir is in a separate pressure regime from the Lower reservoir. In the Lower reservoir sequence, the main reservoir in previous Cladhan wells, the well encountered a gross TVT of 256 feet and a net sand of 21 feet TVT. The sand has an average porosity of 16 per cent. and hydrocarbon saturation of 75 per cent. Initial pressure data indicates that the lower sand is in pressure communication with, and is part of the original Cladhan discovery. The well has proven an Oil Down To of 10,447 feet True Vertical Depth Sub Sea (TVDSS), giving a minimum hydrocarbon column of over 1,200 feet.
Upon completion of operations at well 210/30a-4, the Transocean Prospect semi-submersible rig(photo) will commence the first planned side-track, 210/30a-4z to evaluate the Upper Jurassic sandstones significantly down dip from the 210/30a-4 well in an attempt to define oil water contacts for both the upper and lower reservoir units, as well as investigating the potential for thickening of the upper unit. It is expected that this side-track will take approximately 20 – 25 days subject to weather or operational delays.
Commenting on the latest well result, Graham Doré, EnCore’s Exploration Director said:
“This is an important result for Cladhan. The well has confirmed both the presence of a large oil column in the main Cladhan reservoir as well as a new hydrocarbon bearing reservoir sequence, and has yet to find an Oil Water Contact. The next side-track to the east will evaluate the fan structure some 1,000 feet deeper, and has the potential to encounter improved net to gross as well as establishing Oil Water Contacts for both reservoir sequences. This will be followed by a side-track to the south which is designed to confirm the presence of oil in the Central channel”.
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Source:EncoreOil , April 12, 2011