InterPore2026

4D Imaging Insights into Oil Pathway During Primary Drainage in Natural Porous Media

20 May 2026, 10:05

1h 30m

Poster Presentation (MS10) Advances in imaging porous media: techniques, software and case studies Poster

Speaker

Dr iara mantovani (LNLS/CNPEM)

Description

Understanding multiphase fluid flow in porous media is fundamental to managing subsurface resources (such as allocating pore space for carbon storage and freshwater protection) and ensuring energy security. This study presents preliminary results from a dynamic investigation of the primary drainage process within water-wet carbonate rock samples. The displacement of water by oil is governed by capillary forces, where the non-wetting phase preferentially enters the pores and throats with the lowest capillary entry pressure. According to the Young-Laplace equation, these correspond to the largest radii, producing a continuous pathway through the better-connected macroporous network of the rock. As local pressures or viscous forces rise, smaller pores and tighter throats are subsequently invaded. Specific challenges are posed by the heterogeneous, dual-porosity nature of carbonate rocks, which are prolific reservoir and storage formations worldwide but notoriously difficult to model. Consequently, high-resolution experimental data are essential for observing these complex displacement mechanisms. Traditional static measurements often fail to capture the transient nature of fluid displacement and the associated trapping mechanisms. Therefore, we employed advanced 4D imaging at the Mogno beamline of the Sirius facility (CNPEM, Brazil) to observe these processes in real-time. Recent studies (Singh et al., 2017; Bultreys et al., 2024; Wang et al., 2025) have highlighted that such displacements are highly heterogeneous and characterized by fast, intermittent invasion events (Haines jumps) governed by local capillary fluctuations. For this time-resolved experiment, a 2.5 mm diameter carbonate sample was placed in a fluid cell and then was fully saturated with high-salinity brine. The system was mounted at the nano tomography station of the MOGNO beamline for performing the in-situ experiment. Oil was injected at a constant slow flow rate to simulate reservoir drainage. The system was imaged continuously at a photon energy of 22keV, achieving a voxel size of 2.6 μm with a temporal resolution of 60 seconds between each image. Image datasets were processed using a non-local means edge-preserving filter (Buades, 2005) to facilitate the segmentation of the oil, brine, and rock phases. Our initial findings indicate: i) Oil preferentially invades high-radius pores and throats during early stages of drainage; ii) The formation of complex oil ganglions creates stable pathways through higher-permeability channels; iii) after the breakthrough, significant oil redistribution occurs, leading to the invasion of smaller pore structures.