Maersk Oil has developed the STAR platform which by its simple and flexible design easily can be adapted for different applications and load bearing capacities.
When upgrading the Dan and Tyra production centre facilities, costs have been minimized and additional deck space for production equipment created by establishing bridge connections between an existing platform and a new STAR platform.
Maersk Oil has installed several unmanned STAR platforms, especially on smaller satellite fields. Unmanned platforms are cheaper and reduce operating costs and safety hazards. Another advantage of the STAR platform is that it is re-usable and therefore suitable to be installed on small marginal fields with rapid production decline.
The combination of horizontal wells and STAR platforms has reduced development costs considerably in Maersk Oil operated fields.
The Danish fields produce from predominantly chalk reservoirs which are characterized by high porosity, but very low matrix permeability, mechanical weakness and weak aquifers.
The difficult marginal reservoirs have required Maersk Oil to continuously develop and/or deploy new efficient technologies. On several occasions Maersk Oil has been on the forefront. Recently Maersk Oil has developed and implemented new techniques to improve the water flooding process by the so-called Fracture Aligned Sweep Technology (FAST), by which the reservoir section is being fractured in long continuous and parallel fractures, establishing a near perfect linear sweep between alternating producers and injectors 600 feet apart. This technology was implemented in the development of the Halfdan oil field from the very beginning. Gas reinjection was initially employed in the Gorm oil field for resource conservation and pressure maintenance, and dry gas recycling is ongoing in the Tyra gas-condensate field to increase and accelerate condensate recovery.
Following pilot trials, a full field water flood scheme involving mainly horizontal or highly deviated injectors has been implemented in the Gorm and Skjold oil fields. A similar scheme has been implemented in the Dan Field, where the introduction of horizontal producers doubled the projected recovery from 6 to 12%, and the implementation of water flooding redoubled the expected recovery from 12 to 24%. It was with this fractured horizontal well water injection scheme that Maersk Oil achieved what is believed to be the first true line-drive water flood.
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