Advances in Computed Tomography for Geomaterials: GeoX 2010

Residual CO₂ Saturation Distributions in Rock Samples Measured by X-ray CT

H. Okabe¹ — Y. Tsuchiya¹ — C. H. Pentland² — S. Iglauer² — M. J. Blunt²

¹Japan Oil, Gas and Metals National Corporation1-2-2 Hamada, Mihama-ku, Chiba, 261-0025, [e-mail]

 

² Department of Earth Science and Engineering, Imperial College LondonPrince Consort Road, SW7 2BP, United [e-mail]

ABSTRACT. Understanding multiphase flow and trapping mechanisms in porous rocks at the laboratory-scale is required to design carbon dioxide (CO₂) geological sequestration at the field-scale. Coreflood laboratory experiments on sandstones and carbonate rocks using supercritical CO₂ and brine were conducted with in-situ saturation monitoring by X-ray Computed Tomography (CT). The residual CO₂ saturation obtained by capillary trapping is evaluated experimentally. Supercritical CO₂ is injected into a brine saturated core followed by injection of CO₂-saturated brine. This prevents the dissolution of carbon dioxide into the brine and the amount of CO₂ residual trapping in the rock can be measured. The experimental results show the trapped CO₂ saturation ranging from 0.2 to 0.4 for the rocks with permeability ranging from 6 to 220 md. The proposed method with in-situ saturation monitoring reveals piston-like displacement inside homogeneous sandstone, while heterogeneous flow behaviour is observed on a ...