AIM listed oil and gas group Encore Oil (LON:EO.) this morning reported that drilling was expected to start in the next few days on appraisal wells close to the Cladhan oil discovery in the UK Northern North Sea. Sterling Resources (TSX-V:SLG), the Canadian operator on the block, reported that a rig was currently being mobilised to the site. The aim of the appraisal programme is to drill further down dip, looking for deeper oil in the structure to the east of previous wells drilled there.
The original Cladhan discovery was made in December 2008 but wasn’t drilled again until August last year when further appraisal uncovered a much larger discovery than anticipated. Two months earlier, the EnCore share price began to surge after it made a significant discovery at Catcher in the Central North Sea. Since then, Sterling has produced a resource estimate that puts P50 contingent resources at Cladhan at 89m barrels and prospective resources at 167m barrels. Sterling, as operator, holds a 39.9% working interest in the licence, with Wintershall holding 33.5%, EnCore holding 16.6% and Dyas UK holding 10%
As part of the latest appraisal plans, at least one well and a sidetrack will be drilled using the Transocean Prospect semi-submersible rig. This will be followed by a sidetrack to a second location to an undrilled channel further south of the current well penetrations. Assuming success with both of these wells, there is an option for the Transocean Prospect to drill a second sidetrack from the same well out into the fan system. Information from this drilling campaign will aid in the planning of the field development conceptual design already underway. The expected drilling time for these three wells is 40 days, 25 days and 30 days, respectively.
John Rapach, Sterling’s chief operating officer, said: “We’re certainly pleased to be back drilling after the successful autumn campaign in 2010. Our production test of the 210/29a-4Z well at 5900 barrels of oil per day and then finding oil down dip of that well with the 210/29a-4Y sidetrack have given Sterling and its partners the encouragement to advance an accelerated appraisal drilling program. We have managed to prepare to drill the next well, 210/30a-4 within seven months of re-entering the original discovery well 210/29a-4, in August 2010.”
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