Oil and gas group Encore Oil (LON:EO.) this morning reported that an appraisal well drilled into its Cladhan discovery in UK Northern North Sea block 210/29a had delivered results at the upper end of expectations. A discovery was first made at Cladhan in December 2008 and the follow up well aimed to refine the range of oil volumes by gaining a better understanding of the distribution and thickness of the Upper Jurassic reservoir sands.

The appraisal well was drilled to a total measured depth of 11,215 feet, as a side-track into the Upper Jurassic channel sands, approximately 3,150 feet to the south of the original Cladhan discovery. The side-track encountered excellent quality oil bearing sandstones, resulting in a gross hydrocarbon column of 159 feet with 102 feet of net hydrocarbon pay. The sandstone has average porosity of 21% and average oil saturations of 86%. No oil water contact has been observed.

Modular Dynamic Test sampling for both formation pressures and oil samples indicate good correlation of both oil type and reservoir pressure with the 2008 discovery well. The original discovery well and this side-track have together confirmed a total hydrocarbon column in excess of 273 feet. Drill stem testing will now be performed after which the next phase of the appraisal programme will be to drill a second side-track down dip of the original discovery well in order to confirm the extent of the reservoir and seek to establish the oil water contact.

Alan Booth, EnCore’s chief executive, said: “This is a superb result from Cladhan and is at the upper end of our expectations regarding the quality and quantity of reservoir sands. This result supports the idea that Cladhan is a significant stratigraphic trap which has still not encountered an oil water contact. We look forward to the results of the testing and the second side-track in order to help us determine the oil water contact and thus the extent of Cladhan. Only once this information is to hand will we be able to determine the relevant development options of Cladhan and provide an informed estimate of the potential size of the field.”

Booth said that aside from the exceptional result at Cladhan, EnCore was hopeful of returning to Catcher this autumn, dependent on the signing of a suitable rig contract which is nearing agreement, but not yet confirmed. The group…

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