Objectives of the service
The decommissioning of energy assets entails a chain of complex decisions on environmental impact risks, logistics and worker safety. Operations are strongly affected by several environmental influences such as tides, currents, waves, winds, sea temperature and salinity. Today’s decision-making is typically based on metocean data analyses, assessing for example how many days in a given months or looking a week ahead that the significant wave height is less than a certain threshold. Actual decision drivers, such as heavy lift vessel motions, drag on an underwater ROV by currents, scour holes around the legs of jack-up vessels, are not directly addressed. This approach leads to either unnecessary conservativism or risk underestimation. Cost-efficiency is thus sub-optimal.
DHI MOOD Decom will help decommissioning industry and operators in Oil & Gas and Offshore Wind with:
- High-quality metocean information with quantified uncertainties
- Integration of metocean data with probabilistic measures of workability
- Near-real-time environmental variables for impact monitoring
The high quality of metocean data (forecast and hindcast) will be obtained by assimilation and fusion of satellite data into state-of-the-art oceanographic models.
Accuracy of metocean information and the translation into practical risk measures will be the keys for more trustworthy workability assessments, enabling more cost-effective, safer and compliant operations.
Information on the emergence of e.g. oil spills and sediment plumes will be derived from satellite data.
Users and their needs
MOOD Decom will target two user groups, i.e., consultants and contractors, operating in decommissioning of Oil &Gas and Offshore Wind assets in the North Sea. Consultants support and advice energy asset owners during the tendering phase of a project and operations at sea on cost-estimation, planning optimization, and safety compliance. Contractors execute the operations, providing engineering, vessels and personnel.
From interviews with representatives from the two groups these main needs have been identified:
- Transparent information on weather-related workability for not-interruptible operations
- Maximize efficiency of planning for cost reduction
- Minimize risks related to worker safety and environmental impact
- Trustworthy cost estimation of weather-dependent operations
The main challenges to meet these needs are:
- Reluctancy of the industry to openly discuss business and technical critical information
- Deep-rooted conservativism in planning and execution of operations
- Convincing decision makers on the actual added value of MOOD Decom.
In the feasibility study we focus on the North Sea, but the services can be upscaled globally.
Service/ system concept
MOOD Decom will be an operational web cloud system providing high-quality metocean information for supporting decommissioning activities. Metocean data will be obtained by combining oceanographic modelling with near-real-time ingestion of satellite altimetry and scatterometer data, through assimilation and fusion techniques.
MOOD Decom will deliver the following products:
- EO-enriched metocean data as such, for direct use of customers (forecast and hindcast)
- EO-enriched metocean data integrated with probabilistic measures of actual workability
- Direct access to EO-monitoring of structures at sea in near-real-time
Users will access the products through an intuitive and user-friendly Graphical User Interface which will offer agile workflows for ease and transparent use of the service.
MOOD Decom will be operational 24/7 as a service utilising scheduled processes for continuous ingestion and update of data from external data providers and continuous forecast model executions with extraction of forecast model results. Relevant data will be stored in the central data storage, which will be optimized for large datasets and fast query capabilities.
Space Added Value
The space assets involved in the proposed service are summarized in the figure below
Data from Sentinel 1 will be used for monitoring extent and origin of pollution, e.g. thin films of floating oil. Optical Sentinel 2 data will be used for water quality monitoring, such as turbidity plumes. Furthermore, the succession plan of the Sentinels will guarantee the monitoring required in post-decommissioning.
ESA and NASA altimetry missions like Cryosat-2, Sentinel-3A/B and -6 and Jason-2 & -3 will be assimilated through the data portal to provide near real time ocean currents, wind speed and wave height. Scatterometer missions like ESA ASCAT on board the Metop fleet will be used to provide measurements of the wind direction and wind speed above the sea surface.
Dataflow/parameter extraction and quality control will be established, and the information will be assimilated into existing oceanographic information on i.e., wind, pressure and temperature used to drive the hydrographic forecasting models. The assimilation methods for EO data will be optimised throughout the project and two forecast models (existing) will run in parallel. Using two independent models is fundamental to enable us to establish error/reliability quantification of the service. The extensive validation of the new long-term modelled datasets is based on multiple buoys and satellite data (altimeters and scatterometers), securing accuracy and high quality.
Based on the user needs we gathered during the last months from interviews with regulators, operators and consultants working in decommissioning of Oil&Gas and Offshore Wind assets, we have tailored the business model of the service and designed the high-level technical architecture of the MOOD Decom system.
The interviews helped us to better understand the complexities of a decommissioning project. We learned:
- how the interaction amongst the different stakeholders works during a decommissioning project
- how planning optimization, worker safety and environmental impact monitoring are carried out and what are the associated challenges for the users
- which support tools users currently employ and what are their weakness and strength
- how and in which planning and operational situations our service can be potentially used
We have just completed the Business Case Review and will now enter the last phase of the feasibility study which includes a plan for a follow-on demonstration project. The feasibility study will be concluded in January 2022.