Shell’s persistence pays off
Another gas play is emerging off mid-Norway, following a previous Norske Shell discovery in the Halten Terrace region. The operator drilled the well in block 6406/9 in 308 m of water using the semisubmersibleTransocean Leader, targeting the Onyx southwest prospect. It encountered gas in Jurassic sandstones, and the rig crew subsequently conducted a thorough program of logging, sampling, and testing.
According to Norske Shell, it tested two zones, each flowing at a maximum rate of around 1.4 Mcm/d through a 3/4-in. choke. The Norwegian Petroleum Directorate issued a separate statement, estimating the size of the find at close to 60 bcm producible. If confirmed, this would be second in size only to Ormen Lange in this region and well above reserves in other comparable nearby ‘blockbusters’ such as Skarv and Kristin. However, it is too early to confirm that there is the basis for either a standalone or satellite development to another facility, NPD added. TheTransocean Leaderhas since moved on to explore the Stetind prospect for Hydro in the Voering basin.
Bentec's T-150 rig will allow RWE Dea and its partners to tap deeper-lying sections of the Mittelplatte reservoir.
Shell did have high hopes for the well, admitted E&P Europe Exploration Director, Rien Herber, the company rating Onyx Southwest as one of its global “big cat” prospects. The same applied when Shell first drilled in this area in 2002 on the Tott East accumulation. On that occasion, the result was a sub-commercial discovery, which deflated the industry for quite a while. Herber said data gathered to date from Onyx Southwest suggest the presence of a substantial gas column. Shell plans to appraise the reservoir with a further well and may also drill a second wildcat next year on another nearby prospect. Shell is 30% operator of production license PL255 containing 6406-9 and two other blocks. Partners are Statoil and Total.
Hydro has also struck a rich vein with a wildcat well on block 35/11 in the Norwegian North Sea. TheDeepsea Trym semi drilled the Astero North prospect, just north of the Fram field, in a water depth of 360 m. It found oil and gas in Late Jurassic-period rocks. On test, the well flowed at a rate of 3,150 b/d. Hydro’s Norway Development Director, Lars Christian Alsvik, says the find looked to be “commercially interesting,” and large enough to warrant evaluation of a variety of development options. Production could be tied in through the Troll C platform or the Fram infrastructure.
Field partners agree pipeline routes
Development of Skarv - prior to Onyx, Norway’s largest unexploited gas discovery - finally looks to be coming together. The field’s partners, led by operator BP, have opted to export the gas through the Åasgard Transport pipeline system to the processing plant in Kaarsto, north of Stavanger. Statoil and its partners in Idun - a smaller accumulation viewed as a probable tandem development with Skarv - have taken the same course.
The Norwegian parliament’s decision to ratify the new Tampen Link pipeline, to be installed in 2006, influenced these decisions. Tampen Link will take gas from Statfjord North, in the North Sea, across the median line into the UK’s Flags transportation trunkline, which terminates at St Fergus in eastern Scotland. According to Annette Kvilhaugesik, who has been involved in negotiations for all three projects on Statoil’s behalf, these two outcomes have created a win-win situation for all parties.
Theoretically, the 23-km long Tampen Link line could have been restricted to 22-in. diameter, but it will actually be sized at 32 in. This will provide leeway to feed through further supplies from the Tampen area of the North Sea, in turn giving Statoil and other gas owners greater flexibility with regard to taking up ullage in alternative transportation systems. To accommodate gas from Skarv and Idun, the Åasgard Transport pipeline’s capacity will now be upgraded by around 5% to handle throughput of 26 bcm/year. The two fields have combined gas reserves of 51.5 bcm, and Skarv also contains 92 MMbbl of natural gas liquids.
As for Statfjord North, Statoil and its partners are investing NKr16.1 billion to lift oil recovery to 70% and gas recovery to 75%. The project involves converting the field’s platforms from handling predominantly oil with associated gas to a scenario involving gas with associated oil. Resultant added volumes are estimated at 32 bcm of gas, 25 MMbbl of oil, and 60 MMbbl of condensate. Engineering, construction, and installation contracts totaling over NKr3 billion have so far been awarded to heavyweight contractors Smedvig, Vetco Aibel, and Aker Kværner.
Mittelplate rig re-vamped
The latest phase of RWE Dea’s Mittelplatte oil development in the German North Sea is underway, following completion of a new drilling rig for the production facility in tidal wetlands in the ecologically-sensitive Waddensee. The 2,500 hp, T-150 rig has been designed and manufactured by Bentec Drilling and Oilfield Systems in Bad Bentheim, northern Germany, under a €38 million contract. The existing rig derrick is currently being demobilized to make way for the T-150, which should be commissioned by the end of this year. New multiphase pumps and electrical equipment are also being installed.
With the new rig, the Mittelplatte partners will be able to drill down to a depth of 25,000 ft. The new system’s 1.1 million pound hookload derrick will be equipped with mechanized pipehandling systems, a 2,500 hp drawworks, and a top drive outputting 63,000 ft/lb of continuous torque. The mud system will comprise three 2,200 hp mud pumps rated to 7,500 psi.
Mittelplatte holds over 60% of Germany’s total oil reserves. In tandem with the new drilling facilities, a new pipeline is being laid between the production island and the field’s onshore base at Dieksand, from where extended reach wells have also been drilled out to sea to tap further parts of the reservoir.•
