InterPore2026

Pore-Scale Quantification of Distributed Cement Dissolution in Sandstone as a Baseline for Multiphase Reactive Transport

19 May 2026, 15:05

1h 30m

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

Speaker

Justin Anthony Fink

Description

Reactive transport of CO₂-acidified fluids in sedimentary rocks induces pore-scale dissolution of cementing phases, leading to evolving porosity, connectivity, and flow pathways that critically influence injectivity and long-term storage performance in geological carbon storage. In siliciclastic reservoirs, carbonate pore cement is particularly susceptible to chemical alteration; however, experimentally constrained pore-scale data describing cement dissolution under controlled flow conditions remain scarce. This study establishes a quantitative single-phase reactive transport baseline designed to support the interpretation of subsequent multiphase experiments.
A series of time-resolved HCl–brine injection experiments was conducted on a moderately cemented sandstone containing approximately 10% carbonatic cement under fully water-saturated conditions. Cyclic acid slugs (~2 pore volumes per cycle) followed by brine flushing were applied at low and elevated Péclet numbers to capture transient dissolution dynamics and cycle-to-cycle evolution. To probe late-time behavior, the cyclic protocol was followed by a prolonged continuous acid flood reaching approximately 200 cumulative pore volumes. X-ray micro-computed tomography (µCT) imaging was performed repeatedly on a fixed region of interest located in the center of the sample, deliberately excluding inlet and outlet regions to minimize boundary-driven effects.
Pore-scale image analysis combining grayscale normalization, rigid registration, and solid-phase-restricted difference mapping enabled spatially resolved quantification of cement dissolution and porosity evolution. The experiments yield a mean dissolved solid fraction of approximately 18% relative to the initial solid volume. Axial dissolution profiles remain smooth and bounded along the analyzed length, with dissolution fractions ranging between approximately 16–20% and no monotonic inlet-to-outlet trend. Quantification using a participation ratio yields values close to unity, indicating axially distributed dissolution rather than localized reaction fronts. Three-dimensional connected-component analysis shows that more than 99.99% of all dissolved voxels belong to a single connected structure, while geometric analysis reveals a high surface-to-volume ratio and near-unity spatial extents across the sample cross-section. Together, these metrics demonstrate that cement dissolution proceeds via distributed, network-spanning pore-scale removal rather than instability-driven wormholing or inlet-dominated face dissolution.
The resulting dataset defines a well-constrained pore-scale reference state for chemically driven alteration in cemented sandstones. This baseline provides a necessary foundation for interpreting ongoing multiphase supercritical CO₂–brine experiments, where capillary forces and phase interference are expected to interact with chemically preconditioned pore geometries. By isolating chemical effects under single-phase conditions, the study supports more robust mechanistic interpretation and upscaling of reactive transport processes relevant to geological carbon storage.