The choice of location for the platform takes into account other uses. ONE-Dyas is aware of the effects the project may have on the environment and wants to be a reliable partner and good neighbour. This is achieved, among other things, by ensuring that the activities fit in as well as possible with the (other activities in the) surroundings. All this is done in the safest and most responsible way for both people and nature. ONE-Dyas is committed to proactively seeking dialogue and possible cooperation with stakeholders.
Cumulation test
The research in the cumulation test shows that there are no significant effects due to cumulation of effects of the intended activity N05-A with the effects of other activities that (may) take place in the future. To prevent cumulative effects with future projects of ONE-Dyas itself, ONE-Dyas will ensure that no cumulation of underwater noise occurs during the (simultaneous) implementation of the projects.
After gas production ends, the decommissioning phase follows. When all connected gas fields have been produced empty, the wells are shut down. The dismantling of the installations present depends on the regulations and insights then in force. For this purpose, ONE-Dyas first writes a work plan that must be approved by the State Supervision of Mines. ONE-Dyas has experience in dismantling platforms. For example, ONE-Dyas removed satellite platform P11-E from the North Sea in autumn 2023.
There are two possibilities for closing the wells:
- suspend – the borehole is closed off with a valve.
- abandonment – putting mechanical and cement plugs at various heights in the borehole. Then the plugs and the conductor are cut off and removed 6 metres below the seabed. This ensures that no fishing gear can get stuck behind them.
Gas extraction and nature development need not be mutually exclusive. No other activity may take place within 500 metres surrounding a drilling platform. This means, for example, that no shipping or (trawl) fishing is allowed. This allows marine life to develop undisturbed. The platform provides a hard substrate on which flora and fauna (including shellfish) can develop. Together with nature organisations, ONE-Dyas wants to draw up a monitoring proposal for new research.
ONE-Dyas wants to limit the occurrence and duration of flaring as much as possible. ONE-Dyas, therefore, wants to use the treatment process as much as possible to test newly drilled gas fields after drilling. If flaring is necessary, a birdwatcher is called in to advise on the appropriate time for flaring. Flaring is, as much as possible, done during the day. This protocol is applied by ONE-Dyas by default and so far there have been no incidents with birds.
The effects are investigated in the Nature Assessment.
Construction phase
The driving of the anchoring piles to install the production platform is the main source of underwater noise. This takes approximately two days.
The driving of the anchor piles requires mitigating measures. To mitigate the effects of underwater noise on marine animals, a bubble screen is installed around the platform during the pile driving. This will lead to a considerable reduction of the underwater noise by 7 to 11 decibels. The noise pollution therefore remains within the Dutch and German standards. ONE-Dyas will keep the option open to apply other noise-reduction techniques, as long as these can reduce the noise by a sufficient number of decibels.
Drilling phase
The most significant noise emissions in the drilling phase are caused by the driving of the conductors (maximum of twelve). The driving of each conductor takes approximately twelve hours. The driving of the conductors comply with the legal standards.
Oil-based drilling fluid is always transported and processed on land. Drilling cuttings and water-based drilling mud will also transported. The production water is post-treated with an active carbon filter.
Platform N05-A will be the first offshore gas production platform in the North Sea to run entirely on wind energy. The electrification of platform N05-A with the help of wind energy means a considerable reduction in emissions of methane, nitrogen and CO2 . Emissions from the production platform will be zero, and for the entire project we are talking about an 85% reduction.
