Abstract
Deep-marine basin floor systems are promising candidates for geological CO₂ storage due to
their large capacity and complex stratigraphy. On the Norwegian Continental Shelf, several
exploration licenses for CO₂ storage target such systems, including complex fan systems
serving as a key stratigraphic trap. These systems consist of layers of sand deposited by
underwater channels and lobes that shifted over time; one example of this is the Frigg-
Heimdal reservoir system in the North Sea. Uncertainty in sedimentary architecture, facies
distribution, and connectivity poses challenges for predicting plume migration and trapping
efficiency, as well as in understanding how depositional heterogeneity influences CO₂
migration and trapping.
To address these uncertainties, we employ high-fidelity reservoir simulations using an
analogue model derived from the Karoo outcrop. This approach enables systematic
investigation of how depositional heterogeneity influences CO₂ migration and trapping. We
define scalable concepts to describe migration patterns and trapping efficiency and evaluate
simplified modeling approaches.
Our analysis demonstrates the important impact of depositional heterogeneity in CO₂
storage performance. Variations in facies properties and capillary behavior influence plume
migration, and the results highlight the relevance of fine-scale heterogeneity for predicting
migration patterns in complex fan systems. Through systematic evaluation of different configurations and parameter sensitivities, we identify relationships that can inform
simplified modeling approaches and accelerate simulation workflows.
This work provides insights into heterogeneity controls on CO₂ storage and establishes
concepts that support scalable modeling strategies for complex geological settings. The
findings contribute to improved uncertainty management and the development of robust
workflows for predicting storage security in deep-marine depositional systems.