Expansion of Resources for CO2 Storage on the Horda Platform

CCS is a fast-growing industry that is poised to make an important contribution to global climate action. Carbon-intensive sectors such as the process and waste management industries are increasingly looking to transport captured CO2 emissions to the North Sea for disposal in offshore underground aquifers. The Northern Lights project on the Horda Platform offshore Norway has a central and groundbreaking role in northern Europe's decarbonization efforts. However, the confirmed capacity of the first storage site Aurora is limited, and many more sites will need to be developed in the region to meet the growing demand for CO2 storage. Operators are facing new challenges in developing a portfolio of storage sites that are intricately interconnected, i.e. above ground through a common pipeline network and below ground through regional aquifers. New risks emerge such as loss of storage capacity and knock-on effects of declining hydrocarbon production in the region. Operators need to plan strategies for how to best manage their sites in a commercially viable way when faced with significant geologic and pressure uncertainty. For regulators, it is challenging to ensure optimal licensing of large regional aquifers that balances maximizing regional storage capacity with operator commercial interests. ExpReCCS supports these efforts through needed advancements in digital technology to tackle the interconnectedness of multiple storage sites over a wide region, meeting the needs of operators and regulators for efficient simulation tools with good predictive capacity. The project targets a set of open-access simulation tools to assess the regional impacts of multi-site storage that will provide three key advantages over existing tools: (1) expanding the capability of storage operators to account for regional pressure interference in a simple and effective way; (2) improved methods for assessing large-scale pressure communication in geologically complex regional aquifers; and (3) decision-making support for assessing the trade-off between regional storage capacity and project economics. Several research milestones and results have been achieved. First, a new prototype has been developed that links a coarse-scale regional dynamic model with individual license reservoir models (or site model). This technique allows individual operators to capture regional pressure dynamics in their site models by "inheriting" simulated regional pressure data along their local model boundaries in a relatively cheap and simple way. A variety of tests were used to design the most effective and accurate approach, and the resulting code is publicly available. Further work will extend the model to more complex geometries and geological heterogeneity. The project is also undertaking a detailed study of the Troll regional aquifer using data published by the Norwegian Offshore Directorate. This is a large regional aquifer that is the storage target for the Northern Lights, Luna and Smeaheia licenses. The Troll aquifer is a large 100 x 150 km2 system spanning two thick stratigraphic units, the Dunlin and Statfjord groups that are in pressure communication. Large regional faults bound and intersect the model. Dynamic pressure modeling of multiple sites injecting into highest reservoir quality zones of the northern portion of the aquifer show that pressure interference between different well groups could lead to higher than desired overpressure along the faults. A better utilization of the aquifer is likely possible, but further work is needed to optimize with respect to well locations and rates, a challenging task for such a large system. The project will work on more efficient static assessment and simulation workflow of regional systems that will be demonstrated on the Troll aquifer during the project period.

ExpReCCS targets needed improvements in digital technology to address the broad challenges of multi-site CO2 injection. Developments in digital workflows will support risk reduction activities for operators in site identification, capacity estimation, regional deployment scenarios, and large-scale pressure management strategies. Project results will be used to understand how to optimally develop the Horda Platform into a portfolio of interconnected storage reservoirs. WP1 will focus an open-access simulation concept that will provide a fast and reliable approach to coupling regional and site-scale simulations. WP2 will provide better decision support to operators by integrating models for socioeconomic uncertainty with regional storage simulation. WP3 will apply the new simulation tools to provide insight into optimal strategies for portfolio development and management on the Horda Platform. WP 4 will engage with user partners to gain the industrial experience and data needed to ensure the developed tools can be applied in a realistic setting. The ExpReCCS consortium will apply expertise in reservoir simulation, applied mathematics, geosciences and petrophysics to close gaps in regional storage assessment under uncertainty. ExpReCCS will educate a PhD student as part of an overall goal of increasing national competence in CCS. The project is committed to open and accessible science and will engage stakeholders to increase uptake of results beyond the project.