Potential for Re-use of Oil and Gas Infrastructure on the Norwegian Continental Shelf

Abstract

Re-use of existing oil and gas infrastructure (pipelines, installations, wells) is often mentioned as an option to reduce the costs associated to Carbon Capture and Storage (CCS) deployment. The re-use of infrastructure entails, however, some challenges (e.g. infrastructure availability, capacity limitation, state). Total E&P Norge, together with Carbon Limits and NORCE, have looked more in detail at this topic in the 2nd Life CO2 project presented here. The aim of the 2nd Life CO2 project was to study, at a high level and not on a specific case-basis, the potential for re-use of offshore oil and gas pipelines, platforms and wells for CO2 transport throughout the North Sea in general, and the specific storage potential on the Norwegian Continental Shelf based on The Norwegian CO2 Storage Atlas developed by the Norwegian Petroleum Directorate. Alongside, an assessment of the economic and environmental benefits of such re-use was performed, and knowledge and data gaps were identified. In some cases, these gaps will require further de-risking to set up successful CCS projects involving re-use of infrastructure. For pipelines, open data sources from various countries (Norway, United Kingdom, Germany, Denmark and the Netherlands) were used in the project. Several tasks of the project had to be done in an automated way considering the high number of data points. This approach entails some limitations. Examples include specific aspects of the infrastructure, such as flow direction and to what extent pipelines are linked, which have an important impact on availability. The core idea of the approach was to estimate the year in which hydrocarbon fields are depleted (referred to its ‘end of life’) to determine the time at which the connected infrastructure is available. The end of life of each field was estimated based on resource depletion rather than economic cash-flow evaluations. The collected data set of remaining producible hydrocarbon volume was divided by data of current yearly production rate to estimates how long the fields could operate under current conditions. The assumption is that after this time the connected infrastructure (platform, wells and pipelines) becomes available. The corresponding infrastructure was classified and mapped, and only those available in the upcoming 20 years were studied further. Based on the availability mapping exercise, focus was put on the pipelines that link existing CO2 sources / potential hubs and CO2 storages. Both deep saline aquifers and depleted hydrocarbon fields were considered for CO2 storage. The storage potential for relevant storage sites in the vicinity of the reusable infrastructure was evaluated based on results from The Norwegian CO2 Storage Atlas and specific logs in the considered area. The results from this project displayed that overall, the Norwegian Continental Shelf (NCS) showed less infrastructure re-use potential in the coming 20 years compared to the UK continental shelf and offshore Netherlands. This finding was mainly related to the larger and less mature oil and gas fields on NCS. Thus, overall, the Netherlands and the UK seem more suited for smaller-scale re-use projects in a nearer future such as the Acorn project, whilst the Norwegian Continental Shelf seems more suited for larger-scale infrastructure re-use projects in more distant time-horizons. Some interesting cases on the Norwegian Continental Shelf were, however, singled out to be timely available of pipelines linking potential CO2 storage areas to shore. Given the limited number of large emitters in Norway in the vicinity of those pipelines, the best way to re-use those facilities would likely be to build an onshore hub that could import CO2 from large European emitters with an easy access to waterways or seaports. A few relevant cases were selected for economic and environmental assessment to compare the cost and environmental impact of re-use of oil and gas infrastructure for CCS with new built. The results of these assessments are presented in this article. Before launching CCS projects that make use of existing oil and gas infrastructure in the North Sea, there are, however, still significant data and technological uncertainties which need to be resolved. To ensure a satisfactory state of the re-used infrastructure as well as its availability, future re-use projects are recommended to align with decommissioning plans for oil and gas fields and related infrastructure.