ALVHEIM is located west of the Heimdal field on production licence PL 203 and the first discovery well was drilled in 1998. Well 24/6-2 was originally planned to test the hydrocarbon potential of the A2 North Heimdal T60 sand prospect within what is known as the Lista Formation in the northern part of the licence acreage in block 24/6.
The well was drilled by the semi-submersible rig, Transocean Leader, reaching a total depth of 2,722m and encountered a significant hydrocarbons column. This was the catalyst to an appraisal drilling followed by a decision to develop what had become known as the Alvheim asset with reserves estimated to be about 180million barrels of oil, plus associated gas.
Marathon received approval of its plan for development and operation (PDO) for Alvheim on October 4, 2004. Alvheim – the first field to be developed by Marathon on the Norwegian shelf.
Alvheim core comprises the Kneler, Boa and Kameleon fields with reserves in the order of 158million barrels of oil. Of this, 11.25% of the Boa resource is in UK waters.
Phase one is focused around 10 production wells and two water disposal wells; phase two (2010-11) should be three producers, while phase three (2018 or thereabouts) will concentrate on gas blowdown. Marathon owns 65% of Alvheim, while ConocoPhillips has 20% and Lundin Petroleum 15%.
There are a number of satellites within the greater Alvheim area that offer potentially major upside to the core fields, notably Volund (found 2004: 46million barrels reserves) and Vilje (2003: 52million barrels), both of which are accounted for in the development plan. As indicated, two wells have been completed on Vilje, in which it holds a 47% interest.
Other prospects for tie-in include Hamsun and Grieg (the two are linked).
Grieg was found by Fina in 1994 and, if Hamsun turns out to be commercial, then the two could be developed in tandem. As Roger Wilson put it, there is already an Eiffel Tower’s worth of metalwork laid out on the seafloor at Alvheim – an intriguing measure of the endeavour to date.
The Volund development is said to be making progress towards first production in the second half of 2009 and will be tied back to the Alvheim infrastructure. Marathon has a 65% in this satellite.
Wilson said production-well drilling would continue and that, for example, the eastern portion of Kameleon was likely to be drilled in 2010 and that Volund was still set to come onstream in 2009. Work is being carried out in Stavanger on construction of some of the equipment required for this Alvheim satellite.