Small-scale capillary heterogeneity linked to rapid plume migration during CO2 storage

Abstract

Unpredicted, rapid plume elongation has been observed at subsurface CO2 storage projects worldwide, exemplified by the Sleipner project. We show that conventionally ignored centimetre-metre scale heterogeneity in capillary pressure characteristics can manifest as rapid field-scale, decametre-kilometre, plume migration. We analyse the effect in the Goldeneye Field, UK, a proposed storage site with a unique combination of sample/data accessibility and generality as an archetype sandstone reservoir. We overcome previous barriers by characterising in greater detail over larger scales - the 65m reservoir height at cm-m resolution - and through use of an upscaling scheme which resolves small-scale heterogeneity impacts in field-scale simulations. These models reveal that significant early time retardation of buoyantly rising CO2 plumes is followed by rapid migration under the caprock in the presence of anisotropic, layered heterogeneities. Lateral migration speeds can be enhanced by 200%, placing first order controls on fluid flow and providing a mechanistic explanation for field observations.

Heterogeneous multiphase flow properties of volcanic rocks and implications for noble gas transport from underground nuclear explosions

“…Inasmuch as the previous work does not use direct measurement of multiphase flow properties from UNE sites, the assumption of immobile water is by itself not justified by these studies. Variability in multiphase flow properties within and between lithofacies and fracture systems affects the potentially time‐dependent redistribution of water or gas‐filled pathways—recent multiphase CO 2 sequestration fluid flow studies indicate centimeter‐to‐meter‐scale heterogeneity in capillary pressure affects rapid CO 2 plume migration (Jackson & Krevor, 2020).…”

Observations of the Impacts of Millimeter‐ to Centimeter‐Scale Heterogeneities on Relative Permeability and Trapping in Carbonate Rocks

“…They have also shown that the CO 2 –brine system is sensitive to small‐scale heterogeneity in the capillary pressure characteristics of the rock. These, alongside modeling studies showing the upscaled impacts of small‐scale heterogeneity, show that the laboratory characterization of flow properties using approaches that incorporate the impacts of heterogeneity is key for accurate reservoir modeling (Gershenzon et al., 2017; Jackson & Krevor, 2020; Trevisan et al., 2017; Q. Zhou et al., 2020).…”

“…It is heterogeneity in multiphase flow characteristics that have a particularly significant impact when upscaled from submeter to field scales (Jackson & Krevor, 2020). Small‐scale heterogeneity in the pore structure results in variation in capillary pressure characteristics which results in saturation heterogeneity, and thus, relative permeability heterogeneity (Chaouche et al., 1994; Egermann & Lenormand, 2005; Huang et al., 1995; Krause & Benson, 2015; Krause et al., 2013; Perrin & Benson, 2010).…”

Two-phase gravity currents in layered porous media

“…Heterogeneities in rock properties at the scales substantially amplify and complicate the effect of variations in pore-scale capillary forces, and are manifest in the large-scale saturation distributions within the current. Hence, in order to ensure safe and efficient sequestration, it is imperative to be able to model how small-scale heterogeneities, which are ubiquitous in all subsurface reservoirs, affect spreading rates at the macroscale (Jackson & Krevor 2020; Benham, Bickle & Neufeld 2021).…”

“…2013). Recently, Jackson & Krevor (2020) showed that small-scale capillary heterogeneities can significantly modify the large-scale migration of a buoyant plume within an aquifer. However, their numerical approach is both computationally intensive, and does not provide general scalings for different types of heterogeneity.…”