Shetland gasline plan has multiple benefits

BP Amoco is considering importing gas to its Magnus oilfield, 150 miles northeast of Shetland.

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BP Amoco is considering importing gas to its Magnus oilfield, 150 miles northeast of Shetland. By injecting gas into the reservoir, the operator hopes to boost recovery by 50 million bbl, and prolong the field's life beyond 2015.

Numerous options have been considered. One would be to pipe the gas from the Foinaven and Schiehallion fields, situated 110 miles west of Shetland, through a new 12-16-in. line to the Sullom Voe terminal on the main Shetland island. From there, a pipeline of similar diameter would carry the gas onward to Magnus. An NGL/gas mix would then be injected into the reservoir, necessitating re-completion of certain wells. An import riser and compressor would also be fitted to the Magnus platform.

A decision on whether to proceed will not be taken before mid-2000. However, other advantages to the scheme are:

  • Reduction of volumes flared from Foinaven and Schiehallion
  • Provision of further power export opportunities to the Shetland Islands.

More extended reach wells at Wytch Farm

On the Dorset coast, in southern England, BP Amoco continues to bring onstream world record length extended reach wells at its declining Wytch Farm oilfield. The 19th such well since 1993, M16, was drilled 11,278 meters into the offshore part of the Sherwood reservoir, with a horizontal step-out of 10,728 meters. To aid torque management on this well, torque-reducing plastic beads were deployed, mixed with drilling mud. M16, which took over 130 days to complete, is generating over 20,000 b/d.

Another BP Amoco-operated field, Bruce, will host a new third party development, depending on the outcome of a current FEED study. BHP plans to tie back the 30-million-bbl-oil prospect, Keith, 7 km to the Bruce II subsea manifold via a single appraisal well (converted to a producer). This solution is considered preferable to a direct link to one of the Bruce platforms.

Phillips takes action on Maureen

Phillips Petroleum UK is facing up to closure of its Maureen field in block 16/29a, which has produced over 220 million bbl of oil since startup in 1983. It has just commissioned Aker Offshore Partner for engineering related to the refloat and towaway of the steel gravity base Maureen Alpha platform. In its day, the platform was the only large drilling, production and accommodation facility designed for reuse elsewhere following float-out.

For some time, Phillips has been offering the platform for shallow water operations (70-120 meters) in the North Sea, the Americas, Africa, and Australasia.

If no buyers are found, the platform could be de-constructed onshore and recycled. Decommissioning is due to start next summer. Aker was selected as one of the only two companies with experience of building and installing North Sea gravity base platforms.

Aker Maritime is considering taking on management of marginal Norwegian oilfields. It may even enter the bidding for the nation's upcoming 16th licensing round, which will focus on Mid-Norwegian plays close to existing discoveries - with perhaps a few frontier blocks tossed in as well. However, Aker's ambitions in this regard may hinge on changes to Norway's legislative and regulatory framework.

Another Norwegian-owned contractor, Petroleum Geo-services ASA, already performs a lead role on Conoco UK's Banff field, where it monitors reservoir performance, as well as managing the FPSO. It has just negotiated a similar arrangement with Saga in the Norwegian sector. Saga has agreed to lease its Varg FPSO and operations to PGS for the remainder of the field's life. The vessel can process up to 57,000 b/d of oil and 1.5 MMcm/d of gas, with storage space for up to 470,000 b/d. Despite recent appraisal success, the field has proved a disappointment to Saga, which brought it onstream in 1998.

Chipiron doubles Spanish reserves

Offshore Tarragona in Spain, Repsol reports a new oil discovery, 10 km from its Casablanca platform. The Chipiron-1 well flowed 7,000 b/d of 40° API crude on test. Repsol plans a subsea completion tied back to the platform via a pipeline. From there, the oil would head through an existing line to a refinery in Tarragona on the northeast coast. The new find should double production from the Spanish sector of the Mediterranean. Casablanca currently produces 6,500 b/d from three offshore fields. Repsol envisages start-up early in 2001.

Bright prospects for Danish oil sector

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Chipiron-1 discovery is off Catalunya, in northern Spain.
Click here to enlarge image

Gas from the South Arne field should be on its way to Nybro on Denmark's west coast. Commissioning of the new associated 24-in., 300 km export trunkline has not been seriously delayed, despite damage incurred during the installation earlier this year.

South Arne's oil began flowing in late July, two years after the development was sanctioned. Seven horizontal wells are being drilled which will bring the eventual yield to 50,000 b/d, making this Denmark's second largest producing field. Daily gas output will plateau at 70 MMcf. The Amerada Hess-operated platform rests on a concrete gravity base with storage capacity of 550,000 bbl.

Denmark's largest producer is the Dan complex in block 5505, onstream since 1972. Output here has just hit a new high of 100,000 b/d, following the addition of 15,000 b/d from the recently drilled horizontal appraisal well MFF-19C (completed as a producer). But this was put in the shade by Nana-1, another new discovery 6 km off the Dan reservoir's northwest rim. Analysts Wood Mackenzie estimate recoverable reserves could top 200 million bbl, which would make this Denmark's largest oil discovery since Skjold in 1997. More significantly, the oil came from the supposedly mature Danian-Maastichtian play, where prospects for new finds were considered limited.

Subsea activity warming up

BG and its partners are close to agreement on a concept for Blake in the Outer Moray Firth. The oilfield was discovered by BG in block 13/24b in 1997 - a recent well operated by Talisman confirmed an extension into block 13/29b. BG says the initial development will focus on the main reservoir's 50-75 million bbl of light oil. The likely outcome is a subsea arrangement using Talisman's Ross FPSO as the host.

Also in the UK North Sea, Texaco aims to pipe gas from its Captain Area B expansion project into the Frigg UK transportation system, via an 8-in., 45-km spur line.

In the Norwegian sector, Kvaerner Oilfield Products is to supply subsea production systems for at least four wells for Norsk Hydro's NKr 2.6 billion Tune project. Tune, with gas reserves of 27 bcm, is being developed as a subsea tieback to Oseberg, with a planned production start of October 2002. Supplies would cover Norwegian gas commitments to European mainland customers until 2010. A second development phase may follow, depending on evolving allocation needs.

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