BG undecided on Maria's scope
BG Group is trying to maximize capacity at its Armada platform in the central UK North Sea, close to the median line with Norway. The single-well North West Seymour light oil accumulation is providing new throughput to the multi-field complex, but BG has in mind a more ambitious subsea scheme for the Maria satellite, 12-km northwest of the platform in block 16/29a. However, the project’s scope will depend on the outcome of an imminent exploration well in neighboring block 16/29c.
Last year, BG and its partners Total and Centrica successfully appraised Maria, a formerly fallow discovery, with a well that identified a 900-ft light oil column. The well was then sidetracked, confirming an extension into the adjacent Maria Horst structure. BG assessed reserve potential at that point at 35 MMbbl.
BG's Armada platform, the proposed host for the Maria field development.
The company aims to start development next summer through a combination of a directional well or two on the Maria Terrace structure, and a re-entry of the Maria Horst sidetrack for re-completion as a producer. Oil from both accumulations would head to Armada via a 12-in. pipeline, with a subsea manifold on Maria Terrace and an in-line pipeline tee on Maria horst. The manifold will be designed to allow future expansion, including a potential flowline from 16/29c, pending the result of this year’s drilling.
As there are no spare risers on the Maria platform to receive the production, BG plans to install a new 30-in. conductor in a vacant well slot to accommodate a flexible production riser. It would also commission an additional first-stage separator for the platform, operating at 3,500 cu m/d, and modify an existing subsea chemical injection package to supply Maria with scale and corrosion inhibitors.
Norwegian gas surge to offset oil decline
Development spending offshore Norway is scaling new heights, but may also have peaked, according to the Norwegian Petroleum Directorate (NPD).
This year, NPD foresees Nkr83 billion in total being allocated to new platforms, wells, pipelines, and associated onshore plant. Thereafter, spending will remain at a high level for a time, tapering off toward 2009 as current mega-projects such as Ormen Lange and Snohvit come onstream.
Over the same period, NPD anticipates total oil production across the sector of 760 MMcm, down 100 MMcm on output in 2000-04. Production of liquids (condensates, NGLs) looks set to decline by 5% annually from 2008 onwards, although gas sales should soar 50% from 80 bcm in total this year to 120 bcm in 2011. The big contributors will initially be existing powerhouse fields such as Aasgard, Kvitebjorn, Sleipner Vest, and Troll, supplemented increasingly by new supplies from Kristin, Snohvit and Ormen Lange.
Nearly 10% of gas sold during 2005-09 will come from new projects, NPD adds, one of which will likely be Tyrihans in the Norwegian Sea. Operator Statoil recently submitted a development plan to tie the field back to Kristin’s semisubmersible platform, 35 km to the northwest. The scheme calls for four subsea templates, one to accommodate seawater injection, with injection gas from Aasgard providing further pressure support.
Statoil estimates Tyrihans recoverable potential at 34.8 bcm of rich gas and 182 MM bbl of oil and condensate, which will be extracted through nine producer and three injector wells, the majority being multilaterals.
The export pipeline to Kristin will require electrical heating to avoid hydrate formation. Following processing onboard the Kristin semi, gas will be exported through the Aasgard trunkline to Kaarsto, with oil and condensate dispatched to the Aasgard C storage vessel.
Ramco perseveres off Ireland
Ramco Energy remains afloat, despite incurring crippling losses following water ingress in its Seven Heads field gas wells off southern Ireland. The intrusion brought production to a halt soon after start-up in 2003, and deliveries, via Marathon’s Kinsale Head complex, have been way below expectations. However, banks and a major creditor have stayed sympathetic, giving the Aberdeen-based independent more time to find a buyer for its controlling 86.5% interest in the gas fields.
Partly, this is due to the attractions of its remaining exploration portfolio, spread between shallow water and mid-depth basins off southern and western Ireland, and acreage on and offshore the Balkans. The Irish interests include untapped oil beneath the Seven Heads gas reservoir. Ireland’s government recently extended Ramco’s licensing options for this prospect, and another independent, Island Oil & Gas, is supporting the ongoing technical assessment program.
Ramco also won extensions for nearby acreage known collectively as East Kinsale, Middleton and Rosscarberry, the latter containing an undeveloped gas discovery, Galley Head. On East Kinsale, the company has identified new exploration leads in Cretaceous Greensand and Wealden sands through re-interpreting existing 2D seismic. Off northwest Ireland in the Donegal Basin, Ramco retains a frontier exploration license covering an area of 101,000 acres. The partners are still looking to drill the Inishberg prospect, in Triassic Sherwood sandstone, in 320 ft of water.
Island has just been awarded a frontier license of its own in the Northeast Rockall Basin, covering blocks 18/10, 19/1, and 19/6. The 715-sq-km Killala license area extends over deepwater 70-km off the west coast, and 35 km north of Shell’s Corrib gasfield, which is currently under development.•
