Characterising along- and across-fault fluid flow properties for assessing flow rates and overburden fluid migration along faults - A case study from the North Sea

The article highlights the importance of understanding the permeability of fault zones as fluid migration pathways, with an example from the Vette Fault Zone in the North Sea. The study characterizes the hydraulic properties of the fault zone by mixing host rock lithologies into the fault zone and deriving the fault width from empirical relationships. A parametric study with 1125 model realizations was conducted to understand the sensitivity related to uncertainties in overburden lithologies and fault width correlations. The study found that the fault zone significantly alters the flow-field compared to a model that only considers lithological juxtaposition. The most significant hydraulic communication in the Vette Fault Zone is downwards from the storage reservoir where sand is mixed into the fault zone. The models highlight the potential for downward hydraulic communication along the fault for brine and CO 2 capillary sealing towards the overburden. Thematic collection: This article is part of the Fault and top seals collection available at: www.lyellcollection.org/topic/collections/fault-and-top-seals-2022