Caracterización de muestras geológicas y su influencia en la capacidad de almacenamiento de CO2 en un medio poroso a escala métrica

Abstract

CONDITION FOR PUBLICATION OF PROJECT. Carbon dioxide (𝐶𝑂2) emissions currently make a significant contribution to global warming, and one of the major challenges in geological storage lies in ensuring their long-term permanence within the subsurface. Several factors—including grain shape, roundness, sphericity, and grainsize distribution—directly influence the petrophysical properties of a porous medium and therefore its suitability for 𝐶𝑂2 retention. This study aims to evaluate the influence of these physical characteristics in sediment samples, specifically comparing river–beach sands with supermature quartz sands. To achieve this, laboratory-scale models were constructed to analyze 𝐶𝑂2 storage capacity under controlled conditions. The research followed a methodology structured in five stages, beginning with the collection of field samples, followed by granulometric classification through sieving and morphological characterization of particles. Subsequently, tests of physical properties such as specific gravity, porosity, and permeability were performed, culminating in CO₂ injection experiments. The results show that the morphology of GCS sands (coarse supermature quartz) was characterized by subrounded grains with an average sphericity of 74.25% and a proportion of ultra-spherical grains of 16.75%. These sands exhibited porosity and permeability values of Φ = 0.31 ± 0.01 and k = 4.80 ± 1.90 D, respectively. In contrast, GRP sands (coarse river–beach) contained 59% subrounded grains with high sphericity, 12.25% subrounded particles with ultra-sphericity, and 27.25% subrounded grains with medium sphericity. Their measured properties were Φ = 0.39 ± 0.02 and k = 1.29 ± 0.16 D. Overall, the GRP sands displayed higher porosity, while the GCS sands exhibited better pore connectivity, allowing for more efficient utilization of pore space. Under slow injection conditions, the GRP sands achieved greater total storage capacity due to their higher porosity; however, the GCS sands demonstrated greater efficiency in filling the available pore space. These findings suggest that GRP sands provide a larger storage volume, albeit with reduced accessibility due to lower permeability, whereas GCS sands offer a smaller storage capacity but allow the fluid to take greater advantage of the available pore network. Keywords: miniFluidFlower, roundness, sphericity, petrophysical properties