Improving marine growth estimates using 3D photogrammetry

Lead Research Organisation: Scottish Association For Marine Science
Department Name: Contracts Office


Offshore infrastructure, including oil and gas and renewables installations, are rapidly colonised by a diverse range of animals and plants (seaweeds), here referred to as 'marine growth'. The nature and extent of marine growth has both engineering and ecological consequences for the performance and integrity of offshore infrastructure. From an engineering perspective, marine growth changes critical structure characteristics affecting performance at both the operational (e.g. drag and loading forces) and decommissioning phases (e.g. jacket lifting/towing). From an ecological perspective, marine growth is the basis for the 'reef-effect' offered by offshore structures; marine growth provides ecosystem services such as water filtration, food provision and shelter (e.g. for commerical fish species).

The scale of offshore energy, and the associated installation and removal of structures, is considerable and includes the commissioning of new wind-farms (up to 50,000 wind-turbines are projected by 2050 in Europe) and decommissioning of oil and gas structures (>20% of North Sea assets to be decommissioned within 10 years).

Industry needs to monitor four aspects of the marine growth (MG) on their installations. These aspects are marine growth type (e.g. mussels, coral, anemones) mass, volume and surface roughness. Accurate estimation of these aspects is required in order to (1) inform engineering decisions that account for effects of marine growth, (2) optimise cleaning regimes and planning, (3) inform lifting operations at decommissioning and (4) organise disposal of the marine growth. Marine growth estimates are also required to understand the ecosystem-services offered by offshore structures and thus the environmental consequences of installing and removing infrastructure. This information is also required by regulators and policy-makers as an evidence base to optimise decision-making with respect to consenting offshore activities.

Currently, industry employs a simple algorithm to estimate marine growth thickness and mass on their structures. This algorithm frequently results in substantial overestimates (up to a factor of 20) between predicted and reported MG mass. The current poor MG estimates result in a high degree of uncertainty, for example in the equipment necessary to lift a structure, and this uncertainty incurs considerable costs.

Our project will build on on-going research to assess the feasibility of generating, and analysing, 3D images derived from video footage obtained using remotely operated vehicles (ROV). We will calibrate the MG volume estimated from the ROV-3D images against different MG categories (seaweed, hard-growth, such as mussels, and soft-growth, such as sponges and anemones). We will then take ROV footage gathered around oil and gas structures that have subsequently been decommissioning, and cleaned, and compare our new MG estimates against those recorded by the decommissioning yard. This feasibility assessment will culminate in the production of best-practice guidelines to industry for optimal methods to generate and use 3D images in assessing MG. The knowledge embedded in end-users organisations, as result of this project, will steer adoption of 3D imaging as a novel marine growth assessment tool.

Planned Impact

The expected outcomes of the project are:
1. A best-practice guide to industry/consultancies with detailed methodology for optimising the collection of new ROV footage to meet existing engineering requirements and new marine growth assessments. The guide will include recommendations for subsequent data analysis.
2. An assessment of the feasibility of applying of SfMP techniques to existing ROV footage to generate 3D images of marine growth.
3. Embedding knowledge of the technique with regulators, industry and consultants through production of trade-journal publications and dissemination through industry bodies (via conference presentations, Tethys Annex IV database for renewables).

The benefits of these outcome for project partners, and the wider industry sector and policy makers are listed below:
Benefit 1: Improved mass estimates represent an avenue for significant cost reduction to industry and the government (liable for up to 70% of decommissioning costs and currently subsidising the offshore wind industry). This will result from (1) more informed selection of marine growth removal strategies and lifting/vessel technology during decommissioning, (2) optimising cleaning regimes to minimise disruption to energy generation and (3) informing the design of new infrastructure to account for the damaging consequences of marine growth (abrasion, component wear).
Benefit 2: Involvement of regulators will ensure that the developed technique and outputs are tailored to end-user needs in assessing environmental interactions (e.g. during the decommissioning comparative assessment process) and in relation to waste disposal.
Benefit 3: Utilisation of existing or routinely collected industry data (i.e. ROV footage) for marine growth characterisation will provide operators with additional value and return from pre-existing investments in integrity monitoring.


10 25 50
Description We optimised the generation of 3D images (models) for key marine-growth taxa. Our test sites hosted contrasting marine growth communities (anemone v. mussel) and we successfully generated 3D images from both and determined, from the images, biovolumes of key taxa. We then compared the 3D-model-based volume with the actual volume and constructed statistical models to predict biomass from 3D-model-based predicted volume. We are transferring the skills and knowledge gained from 3D Marg to estimate biovolumes associated with offshore platforms due for decommissioning that are located in Gulf of Thailand. We are working on publication(s) as part of knowledge dissemination.
Exploitation Route Our optimised ROV strategy, biovolume estimation methodology and the taxon-specific conversion of biovolumes to biomasses will be published in due course. This approach will be applicable to any ROV footage (of sufficent quality and overlap) to move between the raw ROV footage, to biovolume and biomass estimates. Publications detailing the approach optimisation and calibration curves are in preparation.
Sectors Aerospace, Defence and Marine,Energy,Environment,Government, Democracy and Justice,Transport

Description We have generated 3D models of oil production platforms in the Gulf of Thailand. Our models will form part of the evidence base used in the assessment of the impact on marine growth (and associated communities) that occur following relocation. Our 3D Marg project was the pilot study that supported our successful NERC Insite Phase II North Sea 3D project which starts in April 2021.
Sector Aerospace, Defence and Marine,Energy,Environment,Government, Democracy and Justice
Impact Types Societal,Economic,Policy & public services

Description Application of novel 3D imaging techniques to quantify biomass and secondary production associated with North Sea artificial structures.
Amount £565,753 (GBP)
Funding ID NE/T010665/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 04/2021 
End 09/2025
Description Auto 3D: Automated marine growth identification Funding Award
Amount £32,303 (GBP)
Organisation The Datalab 
Sector Charity/Non Profit
Start 02/2021 
End 01/2022
Description UHI Energy Hub Knowledge Exchange Grant
Amount £3,000 (GBP)
Organisation University of the Highlands and Islands 
Sector Academic/University
Country United Kingdom
Start 11/2019 
End 12/2019
Description BP 
Organisation BP (British Petroleum)
Country United Kingdom 
Sector Private 
PI Contribution The 3D Marg project has developed methods to create 3D images of marine growth attached to offshore energy infrastructure, which can be used to derive marine growth volume and mass estimates. Assessments of marine growth are essential to enable offshore energy operators to optimise infrastructure design, cleaning and maintenance operations and decommissioning.
Collaborator Contribution Supply of ROV footage
Impact Development of novel 3D marine growth image techniques
Start Year 2018
Description Partnership with University of Western Australia and Australian Institute of Marine Science 
Organisation University of Western Australia
Country Australia 
Sector Academic/University 
PI Contribution We hosted an exchange visit from two researchers from Australia in November 2019. The researchers are looking to apply 3D marine growth assessment to man made structures in Australia and visited SAMS to learn about the techniques that we have developed
Collaborator Contribution Providing skills training to Australia researchers
Impact Two research proposal have been developed and submitted from this partnership, involving UK and Australian reserahc partners 1. NERC INSITE 2. NDRI Australia
Start Year 2019
Description Presentation at Marine Alliance for Science and Technology Scotland's Annual Science Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Presentation on 3D Marg project in the "Understanding the Influence of Man-made Structures in the Ecosystem - Progressing the Science" special session at the MASTS ASM. This led to discussion and collaboration with scientists from the University of Western Australia on applying the technique to offshore energy in NW Australia
Year(s) Of Engagement Activity 2018
Description Presentation at the Structures in the Marine Environment Conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact ~ 100 Academics, stakeholders, industry and government reps, stakeholders and interested parties attended the Structures in the Marine Environment Conference for a day of talks and discussion about manmade structures already within the marine ecosystem (such as O&G platforms and pipelines),and any new infrastructures that may be put in place over the coming decades (e.g. renewable energy structures).
Year(s) Of Engagement Activity 2019