Oil and gas platform during sunrise or sunset

Article   |   Julie Copland   |   11.10.2021

Why sustainable decommissioning of oil and gas wells is crucial for addressing environmental concerns and the knock-on effect it has on local communities

With growing concern around climate change, increased scrutiny is being placed on the energy industry’s carbon emissions. The oil and gas industry accounts for 42% of global emissions¹, and although the transition to more sustainable forms of energy production has begun, oil and gas will still play a vital role in the global energy mix for many decades. Emphasis must be placed upon legacy and late life operations, and the sustainable decommissioning of both onshore and offshore assets to ensure an environmentally-driven solution. There are estimated to be more than 29 million orphaned wells globally, contributing up to 2.5 million tonnes of methane per year². The detrimental impacts of these assets are stark, yet the plugging and sustainable abandonment of these wells could cut emissions by up to 99%.

Julie Copland, head of production technology & decommissioning at Vysus Group, explores ways sustainable decommissioning is reducing the carbon footprint of the oil and gas industry, and its importance in an eco-conscious world.

Repurposing assets

It is possible that some wells can be sustainably decommissioned through the repurposing of the associated assets and infrastructure, reusing the technology and infrastructure for more sustainable operations within the energy industry. However, this relies on effective asset integrity management and ongoing maintenance, throughout an asset’s lifetime. Many orphaned or end-of-life wells have been active since the 1970s and their structures have been situated in inhospitable locations, in acidic soils or offshore with waves and a highly saliferous environment breaking down coatings. Effective asset management is crucial to ensuring facilities are in an acceptable condition, for future use.

Carbon capture and sequestration

One way to repurpose wells is to use the technology in place for carbon capture operations but there are numerous prerequisites that must be met beforehand. Differences in operating criteria often means the metallurgical properties of the pipeline being unsuited to conveying ‘neat’ carbon dioxide. Moreover, there can be complications with shared pipelines. Legacy systems, such as the Forties Pipeline System in the North Sea (169km long), are often highly interconnected and configured for resource extraction. Carbon capture technology relies on inserting gas, which isn’t always feasible in joint pipelines. However, it is an eco-conscious solution that should be considered in the planning process during decommissioning.

Hydrogen repurposing

Another alternative is redeploying existing structures for hydrogen production. This is relevant to offshore facilities which have greater access to the water needed for electrolysis. Through the reorientation of existing technology and distribution infrastructure, it can be used for greener forms of energy. By adopting a sustainable approach, we can ensure less energy is expended on creating new assets, that are themselves carbon intensive in construction, and instead maximise the potential of existing structures.

Desalination in California

As global warming intensifies extreme weather affecting different parts of the world, droughts in areas such as California have become increasingly common. Creating desalination plants from abandoned oil and gas wells potentially represents an innovative production method of freshwater streams. The number of orphaned wells in the region creates a suitable environment to repurpose the wider facilities. Although the well itself cannot be reused, the infrastructure and technology around it can be. There are advanced talks on this issue.

However, there are numerous factors to consider when analysing any potential repurposing projects. Many abandoned oil wells are decades old and have not always been kept in the best of condition through lack of effective maintenance and general erosion. Consequently, it’s sometimes untenable for assets to be repurposed. With effective consultancy, you can analyse the capabilities of existing facilities and the potential for repurposing projects.

Reefing

Legacy offshore assets have been in the sea for so many years, many have become intrinsic to local ecosystems and biodiversity. As they become increasingly ecologically important artificial reefs, supporting a variety of marine life, the removal of the steel jackets as part of a decommissioning process can be environmentally destructive. Sustainable measures can be put in place to remove the topside of wells and relocate the steel jackets onto the seabed. This has been evident in Louisiana where the Vermillian 376 oil platform has been reefed, and designated a national park, supporting local and commercial fishing ventures. One such example saw the population of an endangered fish that fell to just one percent of historic levels, making a reintroduction, where now, year on year their growth is at five percent.

Green decommissioning

When repurposing isn’t viable, other forms of sustainable decommissioning can occur. Just because the existing structure can’t be reused, doesn’t mean that the technology, materials, and equipment can’t be recycled for other projects. For example, there are instances where GT power generators from the 1980s have undergone refurbishment to remain functioning 30 years later. Furthermore, the same helidecks have had many uses from FPSOs to oil wells.

John Cox, global decommissioning director at Worley, a decommissioning consortium partner of Vysus Group, identified many technologies that should be recycled such as gas turbines, valves, and vessels. He estimates only 2% of a decommissioning project should end up as ‘waste’ and should follow stringent regulations to ensure that it’s ethically and environmentally disposed of. All other materials used, such as steel and copper, can be recycled. Embracing this greener decommissioning process reduces emissions because fewer resources will need to be extracted from the ground for other projects. This approach is applicable to a whole range of processes and resources, reducing overall carbon footprint and making the decommissioning process more sustainable.

Transferability of skills

Beyond resources, the expertise of consultants and engineers are equally as transferable to plug and abandonment engineering. Many of Vysus Group’s decommissioning engineers come from drilling or rig completion backgrounds, yet their experience in the industry has equipped them with the skills and technical expertise required. A lot of the equipment used to install the rigs is the same as is used to remove it. This provides another paradigm of sustainable decommissioning. Being able to maintain jobs within the oil and gas industry provides social sustainability to a lot of people who are specialists in this field. Although environmental concerns are at the forefront, being able to address the socioeconomic dimensions, ensures that communities and stakeholders invested in the wells are considered.

Decommissioning as a service

Well decommissioning management is one of the highest cost areas in a well’s lifecycle, comprising about 60% of the total decommissioning cost. Unexpected changes in projects can lead to additional expenditure or delays. There are many complexities with decommissioning and efforts must be made to reduce costs, improve efficiency, reduce environmental risk, and safely abandon wells.

To do this, consultants should evaluate, prepare, and execute well decommissioning plans for single or multi-well scenarios globally. The key is to carefully select a tailored approach to decommissioning and assessing the numerous options discussed to minimise costs yet address environmental concerns and the knock-on effect upon local communities.

Every aspect from cessation of production (CoP) preparation, planning and surveys, to plug and abandonment, waste management and monitoring can all be considered with an environmental lens. Actions must be taken now to ensure the legacy of the oil and gas industry is not stained by increasing numbers of abandoned wells.

References:
1 https://www.mckinsey.com/industries/oil-and-gas/our-insights/the-future-is-now-how-oil-and-gas-companies-can-decarbonize
2 https://www.reuters.com/article/us-usa-drilling-abandoned-specialreport-idUSKBN23N1NL
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