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Energy companies are clear on the central role they must play to achieve net zero by 2050. Carbon capture and storage (CCS) offers significant potential in helping hard-to-abate sectors reduce their carbon footprint and is a major consideration in most countries’ efforts to meet Paris climate targets.
According to McKinsey, CCS activity will need to grow 120 times by 2050 before those net-zero commitments can be achieved. One major element which is often overlooked when considering CCS projects is the role that wells infrastructure, both legacy and new, play in successful project execution. Well engineering sits at the core of successful CCS projects and is an area that must be addressed at the earliest stages of CCS planning.
Hubs of CCS activity are beginning to appear around the world’s mature oil and gas regions. Detailed mapping of these reservoirs and existing energy infrastructure has helped to establish a pipeline of viable projects. Reservoirs will commonly have a stock of pre-existing wells intersecting them, leading both to challenges and opportunities. Legacy wells, even if decommissioned can present well integrity and leak path concerns. However, some may also be suitable for repurposing into wells for CO2 injection.
In major projects, new wells will also be required. Wells designed to support decades of future CO2 injection, constructed to modern well engineering standards.
Although the concept of carbon capture has been around for 40 years, CCS projects have often been viewed as too costly to be commercially viable, with the number of wells having a material effect on the project viability. However, in recent years there have been landmark changes in policy and regulation to drive and enable the CCS industry to scale.
For infrastructure in particular, the UK has introduced the concept of change of use relief (CoUR), which has the potential to encourage the transfer of suitable assets from oil and gas to CCS projects. This is an example where there may be advantages on both sides - transferring liabilities from oil and gas assets due for decommissioning to rapidly accelerate a CCS sector. In certain cases, this may reduce initial CAPEX for CCS and enable an early test of the reservoir for CO2 storage potential.
While existing oil and gas wells may provide an opportunity for repurposing, they also may present a challenge. In working with older wells there are a number of factors that can limit engineering integrity which must be carefully assessed such as improper cementation, improper plugging, overpressure or corrosion. To establish an accurate picture of existing infrastructure, and identify work required to successfully deliver a CCS project in these locations, a detailed understanding must be held of the existing wells infrastructure and the status of both closed (decommissioned) and open wells. This means projects that include older wells require robust planning and expert wells input to be viable long-term.
Early involvement of well engineering can ensure that project risks are addressed during the initial planning phases to ensure the project team understands how viable the existing wells infrastructure is for repurposing, what steps need to be taken to secure well integrity, and crucially identifying potential CO2 leak paths.
The Elemental Energies team recently supported INEOS’ Greensand development in the Danish North Sea. The existing wells were constructed at a time when carbon capture and storage was not a consideration. One of the team’s primary focuses was to recalculate the pressure limits of the well, verify the existing well barriers, and determine if additional well barriers were needed to minimise the risk of leakages.
Designing a programme for either repurposing existing wells or constructing new wells requires detailed integration between wells and subsurface teams. This integration is critical for the understanding of how existing wells infrastructure, new well construction, and the current subsurface environment will interact. The relationship between legacy and new wells together with the changing reservoir environment is critical, and the earlier the wells and subsurface teams can collaborate the more efficient projects will become. This collaboration between subsurface and wells teams is one that Elemental Energies believes is a critical success factor for CCS projects.
In the drive to net zero, delivering CCS relies upon industry capabilities to make projects happen and run them efficiently. Without this, it’s unlikely the industry will get close to achieving the estimated 6 to 10 gigatons of CO2 captured every year that is required by 2050. There are now more than 27 operational large-scale carbon capture and storage facilities around the world, but the potential of re-purposing oil and gas wells creates new opportunities to scale activity in a way that aligns with business goals and global low carbon objectives.
With a vast quantity of oil and gas fields now entering the decommissioning phase, smart CCS projects, led by expert well engineering, could provide substantial carbon-offsetting potential and a profitable avenue as part of the multi-faceted energy transition.
Following the recent acquisition of Norwell Engineering and Senergy Wells, Elemental Energies has more than 15 years of CCS experience. Its leading experts support the delivery of major CCS projects, through the provision of well planning, well integrity and detailed engineering support.
More information on CCS and other Low Carbon capabilities is available here.
By Julie Copland, Head of Production Technology and Decommissioning, Elemental Energies
First published by OGV Energy.
