Monitoring is the means of assessing and analysing a situation. In the case of Brent, monitoring will be used to assess and analyse the seabed around the Brent structures before decommissioning operations begin, and again after they have been completed, to verify that any impacts on the environment are in line with our expectations.
Under current legislation, Shell and its joint venture partner Esso Exploration and Production UK Ltd (Esso) will remain liable for any remaining facilities after completion of the decommissioning operations under the duly approved Decommissioning Programmes.
What monitoring has been completed so far?
In 2007, we completed a pre-decommissioning baseline environmental survey – this was used to provide essential information for two of the supporting documents in the Decommissioning Programme. A further survey was completed in 2015. Together, the data from these surveys provides a detailed assessment of the status of the seabed around each structure before offshore decommissioning operations begin.
What monitoring will be carried out after decommissioning?
A post-decommissioning environmental survey will be conducted when all offshore work has been completed, oil and gas debris removed, and a debris sweep carried out. The survey will re-visit the areas previously assessed in the two pre-decommissioning baseline surveys to obtain a directly comparable set of data which will allow us to determine with a high degree of confidence whether the offshore operations have had any impacts on the local environment.
We plan to conduct a second post-decommissioning environmental survey at a later date based on the findings of the first post-decommissioning survey, again re-visiting the previous sampling areas. This would be the fourth in a series of comprehensive and comparable surveys, and should provide a good assessment of the extent of any disturbance caused by the offshore operations, as well as more data on the general character and state of the seabed and its recovery following cessation of production and the subsequent decommissioning activities.
In line with Decommissioning Guidelines, a future monitoring programme will be discussed and agreed with the Department for Business, Energy and Industrial Strategy (BEIS) once the Decommissioning Programme has been approved. Technology to conduct this future monitoring is being assessed at present and is expected to be finalised at the time of execution.