Compared with the previous method of moving the crude off the island by barge, a method that was subject to tidal and meteorological restrictions, the increased transport capacity of the new pipeline link will allow oil production on Mittelplate Island to be increased from the current maximum of 900,000 mt up to 1.6 million mt of crude annually. Including the land-based production, the combined annual production volume of the offshore and onshore operations will be about 2.5 million mt of crude.
The implementation of the technically demanding pipeline construction concept was completed on schedule and is in full compliance with the strict environmental requirements imposed on the project in the Schleswig-Holstein Tidelands National Park. A factor contributing to this success was the constructive cooperation with the relevant authorities and with external consultants advising on safety and environmental protection. The ecological benefits of the project are considerable. Around 2,000 journeys by the double-hulled barges transporting the crude will be eliminated. The environmental track record is further improved thanks to the increased production volume, which will result in a reduction of the total production period by about 10 years.
Safe and environmentally compatible pipeline construction
In the offshore section, two stainless-steel pipelines were laid over a distance of approx. 7.5 kilometers from the dike line at Friedrichskoog-Spitze through the tidal flats off the mainland and on to Mittelplate Island. On the land side of the dike, the pipelines were extended over the 2.8-kilometer distance to the Dieksand Land Station. One pipeline with a diameter of 250 mm is provided for transporting the crude from the island, and the second pipeline, with a diameter of 150 mm, serves as a return line for the reservoir water extracted in the treatment process. On the island, this reservoir water is re-injected into the deposit in order to maintain internal pressure.
The pre-fabricated sections of submarine pipelines were drawn into two parallel horizontal boreholes drilled beforehand. The entire offshore distance was divided into six sections. The pipeline was buried at depths of up to 20 meters. These depths are sufficient to allow the pipelines to pass safely underneath the tideways as well as the dike. Inside the six construction pits along the pipeline route, the piping runs were welded together at a depth of five meters.
The technical concept for laying the pipelines by means of directional horizontal drilling technologies confined the impact of construction on the tidal flats to a minimum. All construction activities out on the tidal flats, including de-installation along the pipeline route, as well as the pipeline construction of the onshore component and the connection of the pipelines to the Dieksand Land Station, were completed successfully and on time.
Processing of the additional crude produced offshore and transported through the pipeline linking the island to the Land Station necessitate significant modifications and upgrades to the land-based treatment plant. The throughput of the processing systems is being boosted from the current capacity of 1.2 million to 2.5 million mt annually.
High level of capital spending on pipeline and drilling rig
The pipeline link required a capital investment of more than 100 million euros. Also in 2005, the production consortium is investing another 50 million euros in the installation of a new and more powerful drilling rig on Mittelplate Island, the "T-150". It represents one of the biggest and most modern drilling rigs in Europe, featuring special equipment to allow it to operate in the ecologically sensitive Wattenmeer tidelands without harming the environment. The replacement of the drilling equipment had become necessary to meet the increasing technical requirements in further developing the oil field as planned. From December this year, the new high-tech rig will drive the drill bit for distances of between 8,000 and 10,000 meters to reach oil-bearing sandstone layers at a depth of 2,000 to 3,000 meters which had not been accessible until now, and so realize the deposit's production potential.
With these current projects, total investments in the Mittelplate operation will exceed 615 million euros by the end of 2005. A major proportion of this investment went towards implementing the high standard of safety that was required in order to meet the special conditions in this ecologically sensitive production area.
This year's sizeable capital spending represents an additional investment in the future, allowing crude oil production from Germany's biggest and highest-yielding oil field to be optimized on a sustained basis. In addition to the total volume of more than 15 million mt of crude already produced here, current estimates of commercially recoverable reserves remaining in the Mittelplate oil field run to a further 50 million mt of crude. With the remaining domestic oil deposits largely exhausted, the Mittelplate deposit, which accounts for just under 65 per cent of national crude oil reserves, continues to make an outstanding contribution to domestic oil production, and hence to the stability of the energy supply in the Federal Republic of Germany.
Most Popular Articles