Offshore Europe

July 1, 2000
Statoil may have tapped a new oil play with its latest discovery off mid-Norway.

Norne satellite, or new fairway?

Statoil's Svale discovery is situated 9 km northeast of the Norne FPSO.

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Statoil may have tapped a new oil play with its latest discovery off mid-Norway. The 6608/10-6 well, the first spudded by the newbuild drillship West Navion, was exploring the Middle to Lower Jurassic sequence north of the Doenna Terrace. Norne, 9 km to the southwest, is the nearest producing field, but the new discovery, named Svale, lies in a structurally higher setting. Preliminary reserve estimates are up to 120 million bbl and 50 bcf of gas.

The well intersected two reservoir zones, with the sands exhibiting good production characteristics. Gross thickness of the oil column - around 175 meters - was greater than anticipated. The oil was also less waxy and with a lower gas-oil ratio than Norne's. There is another promising structure north of Svale which could be drilled later this year. But whatever the outcome, Statoil may prefer to tie Svale back to the Norne FPSO via a subsea template, with production there set to decline. If so, the new field could be onstream by late 2002.

In the Norwegian North Sea, Statoil and its partners have decided against converting the Statfjord B platform to a wellhead installation, with production piped to Statfjord A for processing. A recent study concluded that it would be more economic to keep the field's three long-established platforms producing at peak levels for another 5-6 years. However, in the longer run, some conversion work will be needed to maintain the 70% recovery target from Statfjord, which would also entail further tiebacks of undeveloped satellites.

Another Statoil production stronghold is Gullfaks - here the 'C' platform will shortly take onboard gas supplies from the Gullfaks South Field. According to Statoil, this subsea project will feature the North Sea's largest and heaviest flowline bundle, supplied by Rockwater in Wick, Scotland. The first half of this bundle, 7 km long and weighing 9,000 tons, was recently shipped out to the offshore location, and comprises lines for the wellstream, gas injection, and hot water, as well as assorted control cables. The extra 50 bcm fed in from Gullfaks South should double gas production from the Gullfaks complex over the next 15 years.

Fabricators gain relief in Norway

Fabricator concerns have eased in Norway, following the sanctioning of Statoil's Kvitebjorn and a probable go-ahead for Norsk Hydro's Grane, two projects demanding weighty platforms. Kvaerner clinched the 11,000-ton production module for Grane's integrated drilling/production/living quarters platform, a contract valued at $390 million. As a result, Kvaerner estimates 2,000 man years duty for its work-starved yards in Stavanger and Egersund - the module is slated for delivery in spring 2003. Heerema will install the entire platform, which will weigh 30,000 tons. The 14,000-ton jacket will be barge launched, while topside modules will be delivered via three separate lifts.

In the UK, there are no such spectacular gains in prospect, but development confidence is slowly reviving. A survey of oil company intentions by the Offshore Operators Association (UKOOA) suggests up to 25 new platforms could be needed over the next three years, although half of these will be ultra-minimal jacket structures for the southern gas basin. If true, fewer yards will be jousting for scraps such as the subsea hardware for the four-phase Nuggets gas project - operator TotalFinaElf recently filed a PDO which calls for drilling of six subsea wells linked to the Alwyn North complex through a subsea manifold and a 40 km, 12-in. pipeline.

Ranger, operator of the Columba B/D Terrace mini-fields west of Ninian, has gained the nod for a third phase of development drilling on the B terrace. Two new producers and three new water injector wills will be drilled from the Ninian South and Central platforms. Remaining reserves at the terraces are put at 40 million bbl.

Talisman adds to mature asset base

Talisman Energy, scavenger-in-chief for the UK North Sea, has pushed through more deals for declining assets. This February, it acquired Elf and Texaco's interests in the Piper/Claymore area, thereby landing control of six producing fields, related pipelines and the Flotta oil reception terminal on Orkney Island. Now, Talisman is buying Texaco's operating interests in Tartan, Highlander, and Petronella in blocks 14/20 and 15/16 (subject to government approval).

These three fields muster 11,000 b/d at present through a four-legged steel platform on Tartan. Highlander and Petronella were linked in through subsea templates in the mid-1980s. Remaining reserves had been estimated at 24 million bbl with field closure anticipated in 2008. Talisman, however, sees potential to defer that date, partly by harnessing unexploited finds nearby such as Lowlander, Claymore East and other technical reserves which could add a further 36 million bbl.

Following a series of asset swaps, Talisman also secured control of the Halley oil and gas prospect in the central sector from BP Amoco, in addition to a stake in Shell's Fulmar project. Halley happens to be within striking distance of Fulmar's steel platform, probably via extended reach wells. And the Fulmar pipelines are also of strategic value, as they already transport hydrocarbons from Talisman's Clyde area fields.

Texaco, like other North Sea majors, is focusing increasingly on larger production assets, in its case Caspian and Erskine. Talisman's cash offer may have been timely, in light of the recent damage to Erskine's HT/HP multiphase pipeline. Design deficiencies led to a rupture, which has left the system out of action since January. JP Kenny has designed a replacement pipe-in-pipe which is due to be installed next month.

BP Amoco looks to the skies

BP Amoco is proposing new rescue arrangements for its North Sea installations. The firm wants to replace its existing standby vessel fleet with a combination of search and rescue helicopters and platform-based rescue craft. A review of operations suggested that helicopters would lessen the risk of survivors being manhandled, while also providing more rapid access to medical attention. The aircraft would also provide improved response in poor weather - at winds above 55 knots, standby vessels are not normally called out.

The proposals would apply initially only to fixed production platforms, helidecks on FPSOs, and drilling rigs which are more weather-dependent. All BP Amoco's offshore staff would also be equipped with personal locator beacon wrist watches designed to activate automatically on contact with water.

BP Amoco claims that these measures are cost neutral, but the Emergency Response and Rescue Vessel association has labeled it a cost-reduction initiative. Chairman Jeremy Daniel commented "If this plan had been in force at the time of the Piper Alpha disaster, there would have been an even worse outcome. Not a single person from Piper Alpha was rescued by helicopter. Indeed, helicopters could not get near the platform." The association also foresees problems if a platform is involved in a major incident. In that case, it says, would a helicopter parked on top be able to operate? Or if a helicopter became unserviceable, would an entire field or even sector have to be temporarily closed down? It also points out that vessels have been called out to rescue survivors from ditched helicopters. In such a case, who would rescue the helicopter?