History of Mittelplate oil production
Since October 1987, DEA Deutsche Erdoel AG as operator and Wintershall Holding GmbH as a partner, have been developing Germany’s most significant oil deposit off the western coast of Schleswig-Holstein - safely and in an environmentally compatible manner.
The chronology of the development of Germany’s biggest oil reservoir
Geologists see potential for oil reserves off the coast of Schleswig–Holstein.Initial seismic studies provide information on the conditions underground.
Further seismic studies confirm expectations for oil discovery in the Wadden Sea. The Büsum Dogger 1 well shows indications of oil but not in commercially exploitable quantities.
The initial high oil price creates a greater awareness of the importance of domestic sources of energy. The German oil industry intensifies efforts to boost domestic production.
Second wave of oil price increases hits the German public hard. The oil industry boosts investment in the exploration and production of domestic sources of energy.
The initial concept for exploratory drilling in the Mittelplate region is submitted to the State Mining Authority in Celle. The Mittelplate 1 well strikes oil in August. The oil deposits are located at a depth of 2,000 to 3,000 metres in porous Dogger sandstone formations.
Contracts are awarded for extensive feasibility studies to be carried out. The studies focus primarily on geotechnical investigations and the impact of ice flows and currents on drilling and production facilities. The ecological importance of the Wadden Sea tidelands has a considerable influence on development plans.
Additional wells sunk between May and September confirm the existence of oil reserves, now estimated at 75 million mt of crude. However, reservoir conditions prove difficult.
Possible solutions for a drilling and production island are examined, including a wharf-like construction, a protective circular dike or a sand island protected by sheet pile walls. Models provide valuable information on the safety and the environmental impact of the various designs. The most suitable solution turns out to be the island with sheet pile walls.
The Leichtweiß Institute at Braunschweig University and the Hamburg Ship Model Basin (HSVA) conduct a study of hydrographic and fluid dynamic conditions in the Mittelplate region. Long-term analyses of extreme storm, wave and ice-flow conditions provide information about the maximum forces any construction would be subjected to, as well as providing information relevant to the detailed design.
At the beginning of the year, the overall concept for the construction and crude oil transportation as well as detailed plans for the construction, drilling, production and transport operations are submitted to the relevant mining authorities and to the Ministry of Economics of the German federal state of Schleswig-Holstein. The general operating plan for the Mittelplate pilot project is submitted to the Mining Authority in Celle in October. The Schleswig-Holstein state government gives its agreement in principle for the pilot project to proceed in December.
The Mining Authority in Celle approves the general operating plan which is presented not only to the relevant authorities but also to nature conservation and environmental associations, the fishing industry and other potential stakeholders for comment. Construction work commences in June.
A drilling and production island measuring 70 x 95 metres is built on the Mittelplate tidal flats at the site of Mittelplate 1 well. The island is constructed in the form of a compact, leak-proof concrete-and-steel basin protected by sheet pile walls. The entire construction has only a small footprint within the expanse of the tidal flatlands, and it proves extremely resistant to the forces of nature, as was demonstrated in model tests.
Legislation to establish the Wattenmeer National Park is passed by Schleswig-Holstein’s parliament in July. As shown in the early drafts, Mittelplate is located in the so-called Category 3 Protection Zone, where some commercial exploitation is permitted and oil production within the Mittelplate region is explicitly allowed.
Construction of Mittelplate Drilling and Production Island is completed mid-year, all drilling equipment is in place and the facility is certified for operation by German mining authorities and Germanischer Lloyd.
In September, drilling begins on three extended-reach deviated wells to develop the field.
Completion and certification by Germanischer Lloyd of a double-hull tank barge constructed at Wewelsfleth shipyard. The barge is used to ferry crude from the island to the port of Brunsbüttel , and from there, it is piped to refineries.
October: start of the production test phase to obtain technical and commercial data required for the development of the field. The safety and environmental protection programs are to be tested.
A further well is drilled at the end of 1987 to determine the potential oil recovery rate through water injection.
Around 200,000 mt of crude are produced without incident by October 1988. The concept has proved to be successful in every respect. The initial findings of the environmental studies conducted in parallel with the general operating plan prove that oil production is possible without harming the environment, even in ecologically sensitive regions.
The last of six pilot wells approved as part of the pilot program is drilled successfully.
Mittelplate Island survives the spring storms Vivian and Wiebke, which cause devastation throughout Germany, without sustaining any damage.
Pilot phase completed. The project has proved to be entirely feasible in terms of environmental protection, production engineering, expected production rates and transport safety.
Continuation and expansion of oil production is governed by an extended operating plan approved by the authorities. New findings of the recent environmental studies show that, with the exception of the construction of the island itself, no lasting non-natural changes have occurred in the tidelands. By the end of the year, total crude production reaches 1 million mt.
A new state-of-the-art well is drilled: this one runs horizontally through the reservoir, which allows it to produce more oil as a result of taking a longer path through the oil-bearing sandstone.
The production rate at Mittelplate is to be doubled to around 1,750 mt per day starting in 1996. On the basis of a main operating plan approved by all relevant authorities, the extension measures required for this purpose are carried out on the existing island.
A second tank barge to transport the additional production is built and ready for commissioning by the end of the year.
A second gas turbine is installed on the island to further reduce emissions. Surplus petroleum gas is to be used in an environmentally compatible way by being converted into electricity. This will make the island self-sufficient in terms of its electricity supply. Surplus electricity will be fed into the mainland grid by means of a power cable, which is laid in the autumn.
The upgrade of the technical equipment on the island is completed on time. By mid-year, annual production is raised to 550,000 mt of crude.
Following official approval, additional seismic studies are carried out in the Meldorf Bay area in autumn in an effort to find out more about the deep underground structures in this region. The aim is to close the gaps in the existing, incomplete seismic data and provide valuable information on the exact location and the extent of Büsum salt diapir, the eastern reach of oil-bearing rock towards the coast, and the possibility of accessing more distant sections of the reservoir through extended-reach wells drilled from the mainland.
Findings from the previous year’s shallow-water seismic studies allow experienced drilling crews to drill the first onshore exploratory well during the summer. For this purpose, extensive environmental protection measures are put in place at the drilling site in Friedrichskoog.The Dieksand 1 well is drilled to explore the geological formations near the coast and to evaluate the production potential of onshore wells.
October marks the 10 year anniversary of the start of production on Mittelplate Drilling and Production Island and the operators can look back on a successful track record. More than 3 million mt of crude have been produced without a single incident.The drilling, production and transport concept developed specifically for this extremely sensitive tideland region has stood the test of time in all possible conditions.
Enhancements to the island’s production facilities and the expansion of transport capacities boost the annual production rate to 800,000 mt by year-end. Production continues from existing facilities. A third tank barge is built and joins the fleet transporting the crude produced on the Island.In October, 3-D seismic studies commissioned by the consortium are carried out to find out more about the geological formations in the oil reservoir.
In addition, the results of the Dieksand 1 well drilled from the mainland are evaluated, and preparations for a further well are under way. The drilling operations for the Dieksand 2 well start on schedule at the beginning of December and drilling is expected to take six months. The experts face enormous technological challenges to reach the target horizon at a depth of around 2,000 metres, the well must be deviated and drilled over a distance of almost 8,000 metres in a westward direction.Pioneering advances in engineering – the so-called extended-reach drilling technology – make this possible.
The Dieksand 2 production well is completed successfully in May. Sunk at Friedrichskoog, it reaches the oil-bearing Dogger sands in the eastern section of the Mittelplate field after total drilling length of 7,727 metres – one of the world’s longest extended-reach wells.
Two more wells are drilled in order to secure the field’s production potential. An environmental report presented at the end of the year confirms that drilling and production operations have had no significant impact on the environment.
Positive findings on the potential for exploiting the oil reserves from the mainland as well lead to the start of construction of onshore oil treatment facilities in Friedrichskoog in the spring, along with the construction of a pipeline to transport clean oil, associated gas and condensate to Brunsbüttel, for distribution to customers.
By the end of year, two more extended-reach wells, 8,284 and 8,367 metres in length, are successfully drilled into target formations. The primary aim of the Dieksand wells is to develop the highly productive eastern section of the Mittelplate oil field. The additional onshore production potential is around 1 million mt p.a. Production from the extensive western section of the reservoir, which is inaccessible from the mainland, continues from Mittelplate Island.
The total production from Mittelplate Island by the end of 1999 is nearly 4.9 million mt. Tidal restrictions on the transportation of crude from the island limit the annual production to around 800,000 mt. Schleswig-Holstein’s parliament passes new National Park legislation in October 1999. The operation on Mittelplate Island, now in a Category 2 Protection Zone, is still permitted.
An important new phase in the development of Mittelplate, Germany's biggest oil deposit, begins in June 2000. Onshore production begins in Friedrichskoog after a 15 month construction phase and on completion of a brief production test, bringing crude oil production from the field to optimum levels. By the end of the year, all operations at the Land Station and the oil pipeline run smoothly and incident-free. At the drilling site, the Dieksand 5 well is sunk.
Operations at the drilling and production island again show a positive track record by the end of the year. Over 800,000 mt of crude are produced from the offshore facility without incident. Six months of onshore operations produce 495,000 mt. Total production from the deposit since the start of operations is nearly 6.2 million mt. The latest estimates of reserves indicate at least 35 million mt of exploitable oil, significantly more than the 30 million mt previously calculated. Geologists do not rule out a further increase in the recoverable potential.
Supplementary 3-D seismic surveys are conducted in April to obtain more accurate data on the geological formations in the reservoir and to determine the possibilities of accessing new, more distant sections of the reservoir via extended-reach wells sunk from the mainland.
zoom Drilling teams successfully complete the Dieksand 5 onshore well. On reaching its target, with a drilling length of 8,995 meters, it is Germany’s longest ever extended-reach well and among the world’s top ten. Another extended-reach well sunk in the second half of the year aims to secure onshore operations.
The drilling program begun from Mittelplate Island in the year 2000 continues. Considerable sums are invested this year in renewing and upgrading drilling equipment. In addition, planning is under way to modernise operating facilities and living quarters. Work remains confined to the Island.
The evaluation of seismic surveys conducted the previous year and the results obtained from additional exploration wells have shown that the recoverable reserves from the Mittelplate oil field exceed earlier estimates by a significant margin. Using the existing production concept, the exploitation of this greater reserve potential would take several decades. This course of action would remain feasible under the relevant provisions of the Mining Act.
However, in light of the most recent evaluation of the deposit, new solutions are being developed that are designed to boost the rate of production. The new concept calls for a pipeline linking Mittelplate Drilling and Production Island to the treatment plant at the Dieksand Land Station at Friedrichskoog. Construction of such a pipeline would achieve a considerable boost in transport capacities from the offshore operation compared with the existing method of shipping the crude to the mainland by barge. The onshore production from the horizontal wells would remain unaffected by the pipeline.
Any short-term impact on the environment resulting from the planned construction of two pipelines of approx. 7.5 kilometres in length through the Wadden Sea tidelands and the laying of approx. 2.8 kilometres of pipeline on the mainland to reach the Land Station will be offset by the overall ecological benefits of the project - the pipeline would eliminate the need for about 2,000 shipments of crude using the specially built tug-and-barge units. The required documentation is prepared for submission as part of the prescribed assessment and approval procedures.
The entire annual production volume from the combined offshore and onshore development of the oil field exceeds 2 million mt of crude for the first time in 2002.
The onshore drilling campaign is concluded with the completion of seven high-tech production wells. The last extended-reach production well commissioned in February 2003 has a final drilling length of 8,672 metres and achieves a flow rate of about 400 mt per day.
Operations at the Dieksand Land Station proceed smoothly. The projected annual onshore production will be 1.1–1.2 million mt of crude.
The A16 production well on Mittelplate is also completed and commissioned. With a flow rate of approx. 300 mt per day, its production exceeds expectations.
In the company of guests from the political and business community, administration and the authorities, as well as representatives from the media, the production of the 10-millionth ton of crude from the Mittelplate oil field is celebrated at Friedrichskoog at the end of March. The drilling, production and transportation concept, developed and continually adapted to incorporate numerous innovations, has proven itself time and again. The project, which first and foremost needed to address the environmental aspects in the ecologically sensitive production region, has meanwhile become recognised as a model for similar projects throughout the world.
Following the successful transportation from the mainland and installation on site, the new living quarters and the associated facilities are commissioned in October and are in use. This means that 96 people (instead of the previous 69) can now be accommodated on the artificial Mittelplate Island. The new living quarters are of a much higher standard. The capital investment for the new facilities amounts to € 20 million.
In mid-October 2003, the State Mining Authority at Clausthal-Zellerfeld approves plans for the pipeline link between Mittelplate Drilling and Production Island and the Dieksand Land Station in Friedrichskoog. On expiry of the time limits for lodging objections, the approval becomes effective in December. This integrated offshore and onshore development has proven reliable and is already contributing to the more rapid exploitation of the oil field. The annual production volume increases to 2.22 million mt of crude, with total production to date exceeding 12 million mt.
At the end of March, the contract for the construction of a new drilling rig for the Mittelplate Drilling and Production Island is awarded. The replacement of the drilling rig becomes necessary to overcome the ever-more demanding engineering challenges posed by the continued planned development of the oil field. The new drilling rig is scheduled for installation on the island in the second half of 2005, with commissioning to follow at the end of 2005. The rig will be capable of drilling wells of up to 8,000 metres in length, in a radius of approx. 6 kilometres around Mittelplate Island. The contract is worth just under € 38 million. Meanwhile 17 of a possible 44 possible wells have been sunk from Mittelplate Island. The total volume of production to date exceeds 13 million mt of crude.
Following the conclusion of the planning approval process and the issuing of the licence by the State Mining Authority, preparatory work on the pipeline link commences in October. More than 700 individual pipe segments 18 metres in length will be welded together to form ten piping runs of up to 1,400 metres each by the end of February 2005.
At the same time as the land-based preparations are carried out at Friedrichskoog, the company Hafengesellschaft Brunsbüttel commences work at its own port facilities on the Elbe River on fitting out the twelve offshore work pontoons. These pontoons, up to 100 metres in length and more than 20 metres wide, will be moored in pairs at each of the six construction pits along the pipeline route and serve as working platforms for the construction and drilling operations.
In an effort to optimise the extraction of oil from the deposit, RWE Dea as operator and its partner Wintershall will invest a total of around € 150 million by the end of the year 2005 to implement the new concepts devised to further optimise development and production and to boost transport capacity. The centrepiece of the project is the pipeline link which alone requires a capital investment of around € 100 million. In addition, a large number of operational facilities in the offshore and onshore segments will be upgraded, optimised or replaced.
The date 10 May, 2005 marks an important milestone in the construction of the pipeline link - all twelve horizontal boreholes through the seabed, undertaken in sections and covering a total of 7.5 km, to link Mittelplate Drilling and Production Island to the mainland at Friedrichskoog-Spitze, have been successfully completed. Once the welding operations to link up the six sections of pipeline and the subsequent backfilling operations at the pits are completed, removal of the work pontoons and materials takes place in June. De-installation of the offshore pipeline transportation system and of the transport facilities at Friedrichskoog-Spitze is also completed.
zoom By June, a total of 15 million mt of crude have been produced from Mittelplate, Germany’s biggest oil deposit. The offshore production volume from the current 18 out of a possible 44 wells is 9.5 million mt of crude. The total onshore production volume to date amounts to approx. 5.5 million mt of crude oil.
In July, the ocean-side component of the construction work on the pipelines linking Mittelplate Drilling and Production Island to the crude oil treatment plant at the Dieksand Land Station is completed without incident. This brings the short-term intervention in the Wadden Sea tidelands to a close. The open-trench pipe-laying operation on the mainland to complete the link to the Dieksand Land Station is proceeding on schedule.
August/September: work on upgrading and modifying the facilities on Mittelplate Island as part of the continued optimisation of development and production is in full swing. Transportation on site, assembly and installation of the processing equipment needed to boost offshore production to an annual volume of 1.2 to 1.6 million mt of crude is proceeding on schedule and without incident. The same applies to the work involved to install and connect the equipment and systems required for the commissioning of the new pipeline link.
On Mittelplate Island, the existing drilling rig is replaced with a new, more powerful high-tech rig. The prefabricated components of the supporting structure weighing many tonnes are transported to the island on pontoons where they are unloaded and moved into position by the newly installed portal crane. The modular construction permits assembly using a minimal footprint. Installation of the rig with its superstructure rising up to 70 metres in height and incorporating drill pipe handling and lifting equipment is completed.
The necessary modifications and upgrades to the processing plant at the Dieksand Land Station are proceeding on schedule. The capacity of the treatment plant is increased from 1.2 million mt to 2.5 million mt of crude. Additional process fields, a machinery hall, a gas dehydration plant, a flat-bottom tank, a range of processing vessels and separators are built at the 55,000 m² site, and operations buildings are being expanded and upgraded.
28 October, 2005 - At an event attended by the Minister-President of the State of Schleswig-Holstein, Peter Harry Carstensen, and guests including politicians and representatives from business, public administration and government departments, RWE Dea AG as operator and partner Wintershall AG officially commission the new crude oil transport system.
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 Schleswig-Holstein’s Wadden Sea Tidelands National Park. The ecological benefits of the project are considerable. Around 2000 journeys by double-hulled barges transporting the crude will be eliminated. By the end of 2005, more than 16 million mt of crude have been produced from Germany's largest oil field without incident.
The pipeline link from Mittelplate Drilling and Production Island is performing to expectations. Each day, 2,700 mt of crude from Germany’s most productive oil field are transported to the mainland through the new stainless steel pipeline regardless of weather conditions. The short-term intervention required during the construction of the pipeline did not lead to any long-term impact on the ecology of the tidelands, as has been documented by the results of the monitoring programmes put in place during construction. External experts had been monitoring the project throughout the construction phase in order to observe its impact on seals and birds as well as on the fauna living on the seabed. The results show that the required environmental objectives have been achieved.
On completion of a short test phase, the newly installed high-tech drilling rig on Mittelplate Island has commenced its extensive drilling program. The T-150 rig, which cost approx. 50 million euros, has special equipment that allows it to operate in the ecologically sensitive Wadden Sea tidelands without harming the environment. With its large drilling radius of 6,000 metres around Mittelplate Island and total drilling lengths of approx. 8,000 metres, the drilling rig is capable of tapping the Mittelplate oilfield to an optimum degree.
Since May, the rig has been drilling the A20 well. At the end of June, a new logistics centre for the transport of cuttings from the drilling operations is officially opened in Cuxhaven. Part of the new waste disposal concept, the new facility allows these cuttings, which result from the rotating action of the drill bit, to be stored, transported and subjected to thermal processing, in compliance with strict environmental and safety standards.
Drilling and production operations run incident-free for the entire year. The combined volume from the offshore and onshore production for the year total approx. 2.15 million mt of crude.
The extensive investment program for the offshore and onshore operations launched in 2005 has been completed according to schedule. The drilling, production and transportation concept has been upgraded to incorporate state-of-the-art technologies and practices, and the sophisticated innovations put in place are setting new benchmarks for the industry around the world. Some 670 million euros have been invested to date. Substantial proportions of the sum invested are accounted for by the high standards of industrial safety and environmental protection.
Coinciding with the 20th anniversary, the 20-millionth mt of crude was produced from the reservoir in October 2007. The initial production rates of around 200,000 mt of crude annually have increased more than tenfold. Oil production in the sensitive Wadden Sea tidelands ecosystem has been incident-free throughout this period. The annual production volume meanwhile amounts to more than 2 million mt of crude.
The dynamic development of geophysical processes and drilling technology in recent years has opened up new horizons for efficient drilling and production methods, making it possible for oil production to be continually optimised. In addition to the 20 million mt of crude that have already been produced, based on the data currently available the deposit still holds some 30 to 35 million mt in recoverable reserves. As the remaining oil deposits in Germany are now largely depleted, the Mittelplate field has not only become Germany’s most productive oil field, but with just under 65 per cent of national crude oil reserves it is one of the few proven deposits with a viable future. More detailed evaluations of seismic tests meanwhile indicate that additional oil resources are likely to exist. The question as to whether more oil remains below the Wadden Sea tidelands, and how much of it there is, is to be resolved by drilling exploratory wells.
As Mittelplate’s new T-150 drilling rig for extended-reach wells requires more power, a specially designed machine lays two 20-KV cables at a depth of 6 to 10 metres during autumn. As the machine travels across the tidal flats, the cables are laid into small trenches which are filled in again immediately, in a continuous operation.
In November, the steel structure of the 70-metre drilling tower on Mittelplate Drilling and Production Island is clad in stainless-steel trapezoidal sheeting to reduce noise and light emissions in the ecologically sensitive Wadden Sea National Park region, and to shield the crews from wind and weather.
A new phase in the development of Mittelplate, Germany's biggest oil field, commences at the beginning of October with the drilling of the first multilateral well. The innovative multilateral drilling technology allows crude to be extracted from several reservoir sections simultaneously through a single well. Consequently, the high-tech A23 well only needs to drill through the 4,000 metres distance to the reservoir in the Dogger Beta sandstone once in order to reach three separate target horizons. The new technology will effectively help offset the oil field’s natural decline.
The development of Mittelplate also reaches a further milestone in the autumn - the 25-millionth mt of crude is produced from the deposit on 23 October, 2010. The production of a further 25 to 25 million mt of crude (i.e. a comparable volume) is considered to be technically and commercially feasible.
To reduce light emissions from Mittelplate, an optimised lighting concept is installed and commissioned. The new lighting system is designed to minimise the amount of scattered light falling on the surrounding area and thus prevent attracting birds flying at night. In addition to shielding the fauna around the island, the new lighting concept also contributes to energy efficiency while ensuring that crews can move about safely at night and benefit from optimum illumination of their workplace.
The production volume for the year is about 1.4 million mt of crude.
The official opening of the revamped Mittelplate Info Point in Friedrichskoog is marked in an event held at the end of March and attended by guests from the political and business communities, public administration and representatives of the media. Touch screens, digital games and multimedia partitions installed on the new premises now provide an even more immediate experience of Mittelplate. Since April, RWE Dea has also been hosting a lecture series at the Info Point, for which attendance is free. The lecture topics range from Mittelplate itself via the importance of oil as an energy source right through to fundamental issues relating to energy.
The logistics concept for Mittelplate is optimised both on land and at sea to boost efficiency and environmental compatibility. A new land base is commissioned at Cuxhaven at the beginning of July. Operated by the Cuxhaven-based company EnTec Industrial Services GmbH & Co. KG, the land base handles the transhipments of materials required on Germany’s only offshore oil drilling facility. The existing fleet of supply vessels servicing Mittelplate is also being upgraded, resulting in a reduction of contaminant emissions for each ship movement as well as a reduction in the number of ship movements overall.
The 25-year anniversary of production from Mittelplate is celebrated in October. 12 October 1987 was the day when the first test production test from this oil field was carried out. Oil production in the Wadden Sea tidelands off the coast of Schleswig-Holstein has been running smoothly and without incident for this entire time and it is making a substantial contribution to domestic oil production and hence towards securing the energy supply of the Federal Republic of Germany.
The new Mittelplate A24 well in the south-western part of the oil field has been producing about 300 cubic metres of petroleum per day since mid-February. Its length of 5,759 metres and the deviated well path in particular presented the engineers with considerable technical challenges during the installation.
As of June 2013, our crew members on Mittelplate Island have assumed the sponsorship for the grey seal Juris. The staff of the Holstein Production District support the seal rescue station in Friedrichskoog by paying for feed and for veterinary services.
The land-based wells Dieksand 5 and 7, among the longest deviated wells in the world, were refurbished and fitted with new pumps, allowing them to extract petroleum from an additional oil-bearing sandstone layer starting in February 2014.
At the beginning of March 2015, the sale of RWE Dea AG to the LetterOne Group was finalised. The long and successful tradition of the company will carry on and be developed further in the customary reliable manner under the old and new name DEA Deutsche Erdoel AG.
To ensure the continued high degree of availability of the processing plant, a fifth storey was installed at the Mittelplate living quarters in July 2015. The additional storey increased the height of the Mittelplate living quarters to 26 metres. It also resulted in an increase in the number of bunks from 96 to 106, ensuring that insufficient capacity in the living quarters is now a thing of the past.
Also in July, the dual lateral well A26 commenced production, with a current production volume of 540 cubic metres of crude oil per day. The A26 well consists of a main well measuring 6,100 metres in length, and a deviating branch extending 1,500 metres. In this latest well, the length of the perforated section is a record-breaking 2,461 metres. The success is due to the technical expertise, perseverance and circumspection of the DEA engineers.