After reaching the end of their life, oil and gas wells are usually left abandoned or plugged up with concrete. A new initiative in the UK is proposing a different approach to them – old oil and gas wells to be transformed into test CO2 storage sites.
The initiative is called the Net Zero Rise project and suggests exhausted deep boreholes to be used as test bed sites for carbon capture and storage (CCS), along with geothermal and hydrogen technology. Net Zero RISE is an academic/ industry consortium that brings together Newcastle, Oxford and Durham Universities with industry players – the energy companies Third Energy and IGas.
Relevant: Can Oil Wells Be Reused For CO2 Storage?
The consortium wants to repurpose the existing onshore oil and gas infrastructure (deep wells) as test sites with the purpose of examining the challenges and opportunities for subsurface technologies to meet the UK’s net zero target.
According to the RISE team, onshore test sites would offer a safer and less expensive route to test the carbon storage tech compared to reservoirs under the North Sea. It has also identified around 20 potential wells, mainly in Yorkshire and the Midlands. According to the group’s estimates, one test site would bury around 1,000 tons of CO2, at 1-3km depth. The cost of repurposing a well including monitoring would come to around $6.7 million (£5 million).
The team also proposed the UK to establish its own hub for carbon capture and storage testing, that could not only test CO2 sequestration but also hydrogen storage and geothermal energy. Right now, the proposal awaits funding to take it to the next stage.
“CO2 storage in the North Sea is probably going to be very important, but we need an onshore capability, a national asset, so we can do testing and look at what monitoring is adequate to understand where the CO2 has gone… If we don’t do this soon, we will lose an opportunity to use this infrastructure… These assets are already there, while drilling [new] boreholes is very expensive and adds a certain amount of risk,” said the leader of the project, Prof Richard Davies, at the University of Newcastle.
Hydrogen is also attracting interest as a low-carbon energy solution. Storing it underground would help ensure a secure energy supply. Exploring test sites would also allow scientists to study different rock types that are best suited to trap hydrogen – so far large rock salt formations have been identified as such, even though the UK has few such deposits.
Transforming abandoned oil and gas wells into CO2 storage sites could be a huge leverage for the industry as it would save costs for companies from drilling new boreholes for carbon sequestration. As the industry is growing, potential cost savers that would support its at-scale deployment are critical to be identified at this stage.