Nick Terdre, Contributing Editor
These are busy days for Talisman in Norway, where the company is in the initial stages of implementing two recently approved projects. Yme, the first field redevelopment in the Norwegian sector, was approved in May, followed in June by Rev, the company’s third Norway-UK cross-border tieback.
Yme is due back onstream in early 2009 with a mobile offshore production unit (MOPU) with storage platform leased from SBM. With this concept, a seabed storage tank provides the foundation for jackup legs that support the topsides. This will be the first application of a MOPU with storage platform in the Norwegian sector.
Yme’s platform wells will be drilled by the jackupMaersk Giant through a caisson supported by the seabed tank.
Oil storage and export by shuttle tanker are required because Yme is far from any pipeline infrastructure. But this is not the concept’s only benefit, says John Vemmestad, managing director of Talisman Energy Norge. When Talisman acquired Yme through its take-over of Paladin in 2005, various development ideas were evaluated, including floaters such as shipshaped FPSOs and the Sevan circular FPSO. But an important factor in the choice of the MOPU with storage was that it permitted the wells to be dry.
Easy access to the wells is important as all the producers will be fitted with downhole electric submersible pumps (ESPs) to boost flow - the hydrocarbons have a very low gas-to-oil ratio.
The platform wells - four producers and three injectors - will be drilled into the Yme Gamma reservoir. There are also commercial reserves in the Beta reservoir some 12 km (7.5 mi) southwest which will be produced with subsea wells - three producers and two injectors. VetcoGray will supply the subsea equipment Technip Offshore has been contracted for subsea construction and pipelay.
Talisman is considering importing power to operate the platform from shore, a distance of about 110 km (68 mi). While such an option offers benefits such as reduced emissions and operating costs, the main driver is the additional gas it would make available for injection into the reservoir and the resulting improved oil recovery, Vemmestad says.
The development wells will be drilled by the jackupMaersk Giant. A drilling caisson is part of the tank structure, which will be installed in spring next year. Several wells then will be drilled through the caisson before the topsides are installed in early 2009.
In the plan for development and operation, Talisman puts reserves at 56 MMbbl of oil. But there is potential for additional reserves in the area, and the company has identified two exploration prospects that it plans to drill next year. Other companies are exploring on nearby acreage, and Vemmestad would be happy to see the Yme platform play host to third-party developments. Such a role is facilitated by controlling several elements in the value chain rather than just one, as is the case at Yme. “This is a strategy that’s proved very successful for us in the UK,” he says.
Cross-border specialist
Meanwhile Talisman also is forging a reputation in the North Sea as a cross-border specialist. In May, the company brought Enoch onstream and saw startup on Blane in mid-September - these are the first two developments regulated by the Norwegian-UK cross-border treaty of 2005. Next in line is Rev, which will be tied back to BG’s Armada platform in the UK sector.
In June theMaersk Giant began recompleting two existing Rev wells as producers. The wells will be tied back to Armada by a 9-km (5.6-mi), 12-in. (30.5-cm) pipeline laid by Subsea 7 layship Skandi Navica. A separation module for handling the Rev fluids under construction by UK yard Burntisland Fabrications is to be installed on Armada.
The cross-border treaty does not remove complex issues, but it does provide a framework in which acceptable solutions can be found, according to Simon Churchfield, subsurface manager on Blane. The process works well because the authorities on both sides have shown the will to solve the regulatory issues.
Blane, which straddles the median line with an estimated 82% of the reservoir on the UK side, is tied back to BP’s Ula field in the Norwegian sector. As an example of the kind of detailed regulatory issue which had to be resolved, Churchfield mentions the subsea control system for operating the wells - this is a one-way hydraulic system with the fluid used to operate the controls discharged at the field. A permit was required from the Norwegian authorities to use the fluid, which will be inserted in the system on the Ula platform, and another from the UK authorities for discharge of the fluid, as the wells lie in the UK sector.
In mid-year, operatorship of Blane was being transferred from Talisman in the UK to Talisman in Norway. In the production phase this makes sense as Talisman Norge is better placed to coordinate with BP Norge, which will control the field facilities from Ula.
Rev has benefited from the experience previously gained in resolving regulatory issues, says Jim Tarlton, manager, Mid North Sea Area. “And it’s good to see companies and countries cooperating well together,” he adds.
In addition to the involvement of the two sets of authorities, Rev’s development also is founded on the commercial agreements negotiated by Talisman and its partner Petoro with BG and its partners for the use of Armada’s processing facilities and with the owners of the CATS pipeline system, led by BP, for onward transport of the gas to the UK.
