Jeremy Beckman • London
Sevan boosts FPSO fleet
Just prior to Dec. 25, Aker Marine Contractors installed the FPSOSevan Hummingbird and its 12 mooring lines on Venture Production’s Chestnut field in the UK central North Sea. This will be the first cylindrical Sevan 300-design platform to serve in the North Sea. The second in this series, the Sevan Voyageur, soon will sail to Oilexco’s Shelley field a few miles to the north.
Both platforms have similar specifications – oil processing at 30,000 b/d and water injection at 20,000 b/d. TheSevan Voyageur, however, has slightly higher oil storage capacity of 300,000 bbl. As with their predecessor, the >Sevan Piranema, currently operating for Petrobras off Brazil, the designer/contractor Sevan Production retained the same assembly and outfitting team of Yantai Raffles Shipyard in China and Keppel Verolme in Rotterdam.
The FPSOSevan Voyageur will undergo outfitting at Keppel Verolme in Rotterdam before heading to Oilexco’s Shelley field.
Chestnut, in 120 m (393 ft) of water, is one of the UK’s oldest undeveloped oil fields, having been discovered in 1986. Despite its proximity to Chevron’s Alba complex, the field’s marginal economics defied development until Venture opted for an extended well test in 2005. The results persuaded the company to commit to a single production well scheme with water injector support.
First oil is due early this spring. TheSevan Hummingbird will stay on location for an initial two and a half years, but with the option for four six-month extensions. The exact duration may depend on studies to evaluate the potential for a second production well to increase recoverable reserves from the current estimate of 6-9 MMbbl.
Oilexco recently completed an appraisal program on Shelley that involved drilling 14 well bores to define the extent of this Palaeocene Forties sand oil accumulation. Current plans are for up to three horizontal producers tied in to theSevan Voyageur, with first oil due early this fall.
Talisman transfers Beatrice to Ithaca
Ithaca Energy is the latest Canadian independent to try its hand at tail-end field operations in the North Sea. By end-June, it expects to complete a transaction for the Beatrice oilfield in the UK Inner Moray Firth, close to northeast Scotland.
Beatrice was discovered by Mesa Petroleum in 1979 in block 11/30a, and has produced more than 165 MMbbl of oil to date out of 495 MMbbl in place, thanks to the efforts of subsequent operators BP and Talisman Energy. The recent transaction with Talisman gives Ithaca ownership of the field’s three platforms and operatorship of both the storage/transhipment terminal onshore at Nigg, and the 16-in. (40.6-cm) export pipeline connecting Nigg with the Beatrice Alpha processing platform.
Output from Beatrice has dwindled to 1,800 b/d, which explains Talisman’s willingness to sell for a cash consideration of just $21 million. The Bravo installation is currently shut-in, but Ithaca intends to restore operations as part of a scheme to tie in its nearby 5 MMbbl Jacky discovery.
The tieback could involve placing a wellhead platform on Jacky connected to Alpha and Bravo via new infield lines. Ithaca also plans further exploration in the area, starting with a well on the Manuel prospect. Wood Group will remain as duty holder of the facilities, and Talisman has agreed to retain the obligation for final decommissioning.
Fiscal incentives might help ease the burden of abandonment elsewhere in the UK North Sea. The Treasury has issued a consultation document addressing various issues of concern to the industry, including inconsistencies concerning the application of petroleum revenue tax to decommissioning liabilities. The document also sets out proposals to extend corporation tax loss carry-back to help operators defer decommissioning programs, with the aim of extending the UK North Sea’s productive life.
Franco-Norwegian CO2 studies
Norway and France plan to pool research into carbon dioxide (CO2) capture and storage in underground reservoirs. Numerous collaborations were proposed following a two-day seminar in Oslo in late-November attended by specialists from both countries. Ideas put forward included a scheme to investigate transporting of CO2 from Normandy in northern France to the North Sea for storage.
Both countries are engaged in a series of studies, ranging from basic research to full-scale demonstration projects. StatoilHydro has 11 years’ experience storing CO2 in the Sleipner field in the Norwegian North Sea. The company also plans to build a CO2 capture test facility at the Monsgtad gas power plant in western Norway, which should be operating from 2010.
Total has run a carbon capture and storage program in France since 2001. Later this year, this program will enter a new phase when it begins pumping 150,000 metric tons (165,346 tons) of CO2 into an empty gas reservoir in southwest France over a two-year period. In the Dutch North Sea, Gaz de France has experience with CO2 injection at the K12-B field.
Njord releases first gas
First gas has flowed through the new export pipeline from the Njord field platform in the Norwegian Sea. This follows a $216-million modification program at the Njord complex, previously configured solely for oil production.
During the initial development, oil was drained through 11 producer wells while the gas was re-injected into the reservoir for pressure support. Under the current program, StatoilHydro is drilling new producers to sustain overall output, with further resources phased in from satellite fields. The targeted oil flow is 20,000 b/d, with gas exports of 6 MMcm/d (212 MMcf/d).
The new 40 km (24.85 mi) pipeline ties into the Aasgard Transport trunkline, in turn connected to the processing complex at Kaarsto, north of Stavanger. The pipeline should have been in service early in October. However, measures to rectify a problematic weld were further complicated by bad weather, delaying start-up until mid-December.
In the North Sea, StatoilHydro has more serious problems with a pipeline taking rich gas from the Kvitebjorn and Visund fields to Kollsnes near Bergen. Inspection last October revealed that the line had shifted out of position and suffered external damage. A clout from a ship’s anchor was the probable cause.
Production from Kvitebjorn had been shut down in any case since last May for drilling of new production wells to counter the impact of pressure decline. Gas exports from Visund were halted during the recent inspection program. StatoilHydro is currently working to identify the optimum solution and timing for fixing the damage.
