InterPore2025

OPTIMIZATION OF GEOLOGIC CARBON SEQUESTRATION: EFFECT OF FLOWRATE ON NONWETTING PHASE CONNECTIVITY.

19 May 2025, 15:05

1h 30m

Poster Presentation (MS26) Mechanisms Across Scales in Subsurface CO2 storage: A Special Session in Honor of Sally Benson Poster

Speaker

Daniel Enebe (Oregon State University)

Description

Reducing atmospheric carbon is essential in the global strategy to combat climate change. The International Panel on Climate Change's Fifth Assessment Report emphasizes the critical goal of keeping the rise in global temperatures to under 1.5°C compared to pre-industrial levels. The report highlights that achieving this temperature goal is unlikely without proper deployment of counteractive emission strategies such as carbon capture, utilization, sequestration, and storage (CCUS). Geological carbon sequestration, primarily via the residual trapping mechanism, is a workable approach for efficiently storing CO2 in subsurface formations over comparatively short geological periods. However, careful management of the trapping efficiency is crucial to provide optimal CO2 storage.

According to exploratory research of limited scope (Davis, 2021), reducing the topological connectivity of CO2 within subsurface formations may improve the effectiveness of residual trapping. These preliminary findings demonstrated a correlation between increased CO2 injection flow rates and a reduction in nonwetting phase connectivity, suggesting that higher flow rates may enhance capillary trapping. The purpose of this study was to further examine the effects of different drainage flow rates on nonwetting phase connectivity, which could optimize trapping efficiency, ultimately resulting in better CO2 retention. Proxy fluids represented nonwetting and wetting phases, with Soltrol 220® and water as the analogs for supercritical CO2 and subsurface brine. The study further focused on flow rate-dependent changes in fluid connectivity after injection to identify flow conditions that result in the most efficient residual trapping.

Experiments were conducted under variable drainage flow rates while using a sintered glass bead column, a widely recognized model for porous media. X-ray computed microtomography (micro-CT) was used to capture detailed three-dimensional images of fluid distributions. Imaging was performed at four critical stages: before fluid injection, after the primary imbibition, post-drainage, and after secondary imbibition. Image analysis then allowed for the extraction of connectivity metrics, precisely the Euler number, and phase saturations to evaluate the changes in fluid connectivity and trapping efficacy.

This work provides valuable insights into flow dynamics that could be used to fine-tune geologic carbon sequestration techniques, leading to improved CO2 storage strategies. Ultimately, optimizing CO2 trapping efficiency holds great potential for enhancing the overall effectiveness of CCUS, contributing to the multidisciplinary approach needed to combat climate change.