Autonomous Techniques for anthropogenic Structure Ecological Assessment (AT-SEA)

Lead Research Organisation: National Oceanography Centre (WEF011019)
Department Name: Science and Technology

Abstract

Thousands of Oil & Gas industry structures in the sea are approaching the end of their lives. At this time, they typically need to be removed and the environment returned to a safe state. This process is known as decommissioning. As many of these sites are old (typically 20+ years) and originally were drilled before the current environmental regulations existed, there has often been some contamination of the seabed around these sites. To ensure that no harmful effects will occur, decommissioning operations need to be supported by an environmental assessment and subsequent monitoring. Monitoring may be required over many years after decommissioning, especially if some structures are left in place. Monitoring surveys in the offshore environment are expensive and time-consuming, requiring ships and many specialist seagoing personnel. This requirement, although vital, will have a considerable cost for industry and the public.
Ocean robots, which use computer systems to carry out survey missions by themselves, are regularly used in detailed scientific assessments of the environment. As they collect very high-quality data quickly, such robots have recently been adopted for some tasks by industry but these still require an expensive support ship as they are not capable of long-range missions. Recent technological developments have cut the cost and expanded the range of these robots to thousands of kilometres, making it possible for long-range assessments of multiple sites to be undertaken with a robot launched from the shore. This would have many advantages, improving the quality and quantity of environmental information while cutting the costly requirement for a survey ship and crew. We will carry out the first fully autonomous environmental assessment of multiple decommissioning sites. The Autosub long-range ocean robot submarine ("Boaty McBoatface") will be launched from the shore in Shetland, visit and carry out an environmental assessment at three decommissioning sites in the northern North Sea, before returning around 10 days later with the detailed survey information onboard. The robot will take photographs of the seabed, and these will be automatically stitched together to make a map of the seafloor, structures present, and the animals that live there. Established sensor systems will measure a range of properties of the water, including the presence of oil and gas. As well as the decommissioned sites, the robot will visit a special marine protected area where we know there are natural leaks of gas, to check the robot can reliably detect a leak if it did occur.
On return to shore, the project will examine all the data obtained and compare it to that gathered using standard survey ship methods. We will test if the same environmental trends can be identified from both datasets to determine if the automated approach would be a suitable replacement for standard survey ship operations. The project will also produce a fully documented case study, which includes detailed information on the costs and benefits, practical information on deployments and approaches to reduce the risks and improve the efficiency of operations. This will be used by industry, scientists and government regulators, to demonstrate the techniques and will provide the necessary information to potential users to aid in their adoption. The overall goal of the project is to improve the environmental protection of the North Sea at a reduced cost and to demonstrate how this leading UK robotic technology could be used worldwide.

Planned Impact

Collecting environmental status and monitoring data is critical to gain approval for decommissioning operations, other hydrocarbon industry work and offshore renewable activities. These data are already regularly collected, but work will increase as more industry assets reach the end of their life. As well as the requirement for monitoring in UK waters, companies will have a similar requirement in global operations. Such data are essential to reduce the risk to the environment and are usually a legal requirement. Conventional survey and monitoring rely on equipment lowered from attendant vessels. This results, typically, in physically small, single point samples, and measurements of environmental status. Such survey designs are often sub-optimal, and infrequent sampling in space and time limits the reliability of the resultant analyses, interpretation, and prediction. Such surveys routinely cost millions of pounds. Marine autonomy offers the prospect of substantial efficiency gains over current practice, greater spatial and temporal coverage, higher quality data, and significant cost savings. This will greatly benefit the companies who need these data and may serve as a model for environmental assessment in other applications, beyond decommissioning. In addition, lower costs mean that more frequent monitoring is achievable, reducing the risk of environmental impacts from decommissioning sites going undetected and unmitigated. As an additional impact, vessel operations, which could be greatly reduced by increased use of autonomy, account for significant greenhouse gas emissions and a large proportion of health and safety incidents.
Through the innovative use of autonomous vehicles, the UK government, its regulators, and the relevant authorities, will have access to increased volumes of high quality and directly comparable background data than previously possible. This will allow bodies such as the Department for Business, Energy and Industrial Strategy (BEIS), the Department for Environment, Food & Rural Affairs (DEFRA), and their statutory advisor the Joint Nature Conservation Committee (JNCC), to gain a better understanding of conditions at decommissioning sites and reference sites around the UK. This will enhance the scientific evidence base to support future environmental management strategies at site and regional level. In addition, JNCC will be able to use or access this approach to tackle a parallel challenge, evaluating the environmental status of the UK's large network of marine protected areas (MPAs). As well as demonstrating the approach, this project will contribute directly, with data from the Braemar Pockmarks Special Area of Conservation being provided to JNCC to help evaluate this approach directly.
The project outputs will enhance UK marine capability. Autonomous robotic vehicles are becoming more prominent in marine applications. Developing the Autosub Long Range vehicle and demonstrating its enhanced capability, will provide significant impetus for other companies developing such systems. Increased use of autonomy, with the UK a global centre of excellence, will provide economic benefits for technology and service companies as well as end-users. In addition, it provides a low-cost, high-quality solution for marine survey activities overseas, which could be developed as part of UK government's official development assistance activities.
The large number of offshore installations reaching the end of their life cycle, and the lack of global consensus on how best to tackle the issue of decommissioning, is of great public interest, particularly as it will come at a significant cost to the taxpayer. There is public interest in ensuring that the role of structures, for example as artificial reefs, and impacts of decommissioning are understood to prevent potential ecological impacts during operations. There is also a broad public interest in the marine environment, its status and approaches to monitor it.

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