TEN exploration and appraisal wells are currently active on the UKCS, although that count is 11 if Caithness’s Middle Jurassic Lybster appraisal on block 11/24 of the Inner Moray Firth is included, being drilled from an onshore location. But just two wells were spudded in October, both in the Northern North Sea – Total’s well 8/15-2 on the Palaeocene Sailor prospect, which is imminently to re-spud, and Sterling’s well 210/29a-4 on the Middle Jurassic Cladhan prospect.
Four of the current wells are active in sidetracks: Oilexco’s Hunt appraisal 22/14b-9Z; Maersk’s Upper Jurassic Culzean exploration well 22/25a-9Z; BG’s Upper Jurassic Jackdaw appraisal 30/2a-7Y, where the heavy-duty jack-up, Rowan Gorilla 6, has been on location just short of 13 months since the initial hole spudded on October 8 last year, and in the Southern Gas Basin, Wintershall’s Carboniferous Dimple appraisal 44/24b-7Z. Also in the gas basin, Star’s Esmond 43/13a-5 pressure test well evaluating the shut-in field for gas storage potential is waiting to restart operations following a rig fire.
Nautical’s 9/2b-3 Palaeocene Kraken appraisal in the NNS was abandoned dry, although further appraisal drilling on the field is said to remain on track. Talisman’s Upper Jurassic MacDonald exploration well 14/25a-6 is not indicated as a success, nor is Century’s well 19/2-2 on the U. Jurassic Dolphin Prospect. Bow Valley’s 22/11b-13, which also chased U. Jurassic sands, was abandoned, too, albeit as a sub-commercial oil find. Oilexco’s Palaeocene Huntington appraisal 22/14b-9 has established an extension to the Forties pool on block 22/14a, suggesting the accumulation extends on to part of adjacent block 22/14a. The sidetracked leg, 22/14b-9Z, has since tested the Forties sand at a rate of 2,707 barrels of oil per day. A field development plan is anticipated.
In the Southern Gas Basin, E.On’s Carboniferous Rita well 44/22c-12, initially indicated as an appraisal, was suspended after 110 days as a future gas producer. Venture’s Stamford appraisal 49/10c-7 was completed after 40 days at total depth and is expected to be tied back as a producer to the Markham compression tower.
Imminently to complete operations is Sterling’s East Breagh appraisal 42/13-4, which tested 10.2million cu ft of gas per day from the Carboniferous reservoir. Breagh is thought to have potential upside gas reserves now in the region 850billion cu ft.
Hannon Westwood’s Planned Well Service carries 175 “planned” wells with indications that some 15 more may commence before year end, taking estimated well spuds, excluding sidetracks, to between 70 and 80 for 2008. Exploration levels will now almost certainly outstrip 2007 levels, although the number of appraisal spuds is likely to be down on last year’s figure.
WellSlot is courtesy of UK oil&gas consultancy Hannon Westwood LLP (www. hannonwestwood.com)