The impact of gradational contact at the reservoir-seal interface on geological CO2 storage capacity and security

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11 Citations (Scopus)
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Abstract

The implementation of CO2 storage in sub-surface sedimentary formations can involve decision making using relevant numerical modelling. These models are often represented by 2D or 3D grids that show an abrupt boundary between the reservoir and the seal lithologies. However, in an actual geological formation, an abrupt contact does not always exist at the interface between distinct clastic lithologies such as sandstone and shale. This article presents a numerical investigation of the effect of sediment-size variation on CO2 transport processes in saline aquifers. Using the Triassic Bunter Sandstone Formation (BSF) of the Southern North Sea (SNS), this study investigates the impact a gradation change at the reservoir-seal interface on CO2 sequestration. This is of great interest due to the importance of enhanced geological detail in reservoir models used to predict CO2 plume migration and the integrity of trapping mechanisms within the storage formation. The simplified strategy was to apply the Van Genutchen formulation to establish constitutive relationships for pore geometric properties, which include capillary pressure (Pc) and relative permeability (kr), as a function of brine saturation in the porous media. The results show that the existence of sediment gradation at the reservoir-seal interface and within the reservoir has an important effect on CO2 migration and pressure diffusion in the formation. The modelling exercise shows that these features can lead to an increase in residual gas trapping in the reservoir and localised pore pressures at the caprock’s injection point.
Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalInternational Journal of Greenhouse Gas Control
Volume72
Early online date19 Mar 2018
DOIs
Publication statusPublished - 19 Mar 2018

Keywords

  • CO2 Sequestration
  • Relative Permeability
  • Capillary Pressure
  • Clastic Sediments
  • Reservoir Modeling & Simulation

ASJC Scopus subject areas

  • Energy (miscellaneous)
  • Engineering (miscellaneous)
  • Earth and Planetary Sciences (miscellaneous)

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