May 1, 1999
Siri's self-installing platform and storage tank (photo courtesy Marine Structure Consultants). [38,365 bytes] Location of the Elf-operated gas-condensate discovery, near the Elgin Field. [10,135 bytes] Drilling levels are down in UK waters, and operators are increasingly coy about well results. Six months after the well was spudded, and a month after the news was leaked, Elf finally confessed that it had a significant gas-condensate discovery 5 km from the Elgin/Franklin complex in the
Jeremy Beckman

UK drillers mass west of Shetland

Drilling levels are down in UK waters, and operators are increasingly coy about well results. Six months after the well was spudded, and a month after the news was leaked, Elf finally confessed that it had a significant gas-condensate discovery 5 km from the Elgin/Franklin complex in the central North Sea.

Heavy duty jackup Transocean Nordic drilled the well in block 29/4d, encountering hydrocarbons at a depth of 5,600 meters. On test, gas flow of 23 MMcf/d and 2,100 b/d of associated condensate were achieved. The discovery will likely be factored in future into the high pressure, high temperature Elgin/Franklin development, which is sharing an export pipeline to Bacton, England with the Shearwater Field.

Elf's reticence follows a spate of tight hole status wells, particularly west of Shetland. Conoco has still not acknowledged its Onslow discovery in this region last year, which had to be heralded by partner British-Borneo. Operators seem wary that revelations (good or bad) will impact future acreage trade-outs. They are also loath to declare Shetlands exploration programs too loudly for fear of stalling motions by Greenpeace.

Deepwater drilling in this area is not benefiting from tumbling rig rates, as the advanced semisubmersibles required remain in short supply. And with exploration budgets generally constrained, it's getting harder to gain partner approval for high risk wells.

Nevertheless, analysts Wood Mackenzie are forecasting up to ten new exploration wells this year in the Atlantic Margin, making it the only UK sector to see an upturn. By contrast, Southern Gas Basin well starts may finish 50% down on 1998 levels due to the low spot gas price in Europe, and in the UK northern North Sea, Shell may be the only active driller. The upshot should be 30-40 well starts on the UKCS this year, analysts predict - the lowest since the late 1970s.

License progress in Norway, Denmark

Eighteen oil companies responded to acreage tenders in this year's Norwegian North Sea licensing round. Awards should be issued next April. Thirty-three blocks were made available, mainly in mature acreage within striking distance of production infrastructure in the west and north of the sector - but only 20 blocks were applied for. Most of the major international players bar Chevron submitted bids, along with independents such as Ugland and Germany's RWE-DEA. Norway's Energy Minister Marit Arnstad claimed she was satisfied with the level of interest, given the climate of low prices and uncertainty.

Offshore western Denmark, Agip has gained a license under the government's open door licensing procedure, which relates to areas east of the 6 degrees, 15 minutes line of longitude - just out with the heavily explored Central Graben. The new license covers 13 blocks or part blocks within Quadrant 5506 on the Ringkoebing-Fyn high, just west of the Horn Graben. No wells at all have been drilled here.

Wood Mackenzie says Agip may be tracking a potential Tertiary play analogous to Statoil's Siri Field to the northwest, but any associated structures may well be small, with doubts over the source given the length of migration paths that would have to extend from the Central Graben.

Siri itself recently flowed first oil through a single producer, although more development wells are being drilled by the Noble George Savageau. In time production will peak at around 50,000 b/d. The self-installing jackup production and accommodation platform - configured for minimal offshore hookup - rests on a 314,500 bbl capacity steel storage tank on the seabed. Kv?rner and Marine Structure Consultants in Schiedam, The Netherlands, were jointly responsible for the design.

All gas routes leading to Heimdal

Norwegian government approval for Statoil's Huldra Field development, coinciding with a new gas export pipeline from Oseberg, will re-establish the Heimdal complex as a major North Sea hub. Since Norsk Hydro gained operatorship of Heimdal from Elf in 1997, opportunities for tie-ins seemed limited to a few small gas-condensate satellites.

Huldra, however, is a substantial field thought to house 685 bcf of recoverable gas and 45 million bbl of condensate in Brent formation Mid-Jurassic sandstones. These are to be developed via a wellhead platform featuring partial separation. The gas will then be piped for further processing to a new riser platform next to the Heimdal installation, before heading off to continental Europe through the Statpipe/NorFra trunklines. Allseas is slated to lay the Huldra-Heimdal link this season. Condensate will be piped initially to the Veslefrikk production semi, after which it will continue on through the Oseberg transport line to Norway's Sture terminal.

Also this year, EMC will install a 110 km, 36-in. dry gas pipeline between the Oseberg complex and Heimdal. Statoil will operate this new line, with Total, Conoco, PetroCanada, Svenska and Norway State DFI the other participants. Capacity could be sized at up to 1,160 MMcf/d.

The new line gives an extra outlet to the gas distribution network beyond the Oseberg-Kaarstoe-mainland Europe route. In the future, the Heimdal complex could also be used to divert Norwegian gas to the UK via a tie-in to the Frigg pipeline system.

Marathon goes for subsea repeat

Enterprise's upcoming appraisal of its Corrib discovery in the Slyne Trough supposedly holds the key to Ireland's gas production future. However, Kinsale in the Celtic Sea is far from a spent force. Operator Marathon is to tie its 1995 Southwest Kinsale gas discovery (in 300 ft of water) back to one of the two main Kinsale Field platforms a few kilometers distant, through a pipeline and control umbilical. The arrangement should mirror that for Ballycotton, Marathon's first subsea development in Irish waters, which came onstream in 1991. Southwest Kinsale will be fast-tracked to achieve first deliveries to Bord Gas Eireann this fall.

Originally, Southwest Kinsale had been mooted as a storage facility, but the idea was discarded as a commercial non-starter. Concurrent with the new development, Marathon is upgrading the Kinsale platforms with new compressors - due in service by mid-2000 - in order to extend deliveries to BGE beyond 2005.

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