InterPore2026

Unveiling the Implications of Reservoir Rock Wettability on the Efficiency of Carbon Dioxide Residual Trapping: Insights from Advanced NMR Core-Flooding

21 May 2026, 10:05

1h 30m

Poster Presentation (MS06) Interfacial phenomena across scales Poster

Speaker

Amer Alanazi

Description

Objective (25-75 words)
Carbon geo-sequestration (CGS) is a key strategy for mitigating anthropogenic CO₂ emissions and addressing global climate change. A critical factor influencing the effectiveness of CO₂ storage in subsurface reservoirs is rock wettability, which governs trapping mechanisms and long-term containment security. However, significant uncertainties remain in predicting CO₂–rock wettability behavior under realistic reservoir conditions at micro-meso-macro pore scales, particularly in the presence of organic compounds.
Methods (75-100 words)
To address these challenges, we conducted a series of in-situ Nuclear Magnetic Resonance (NMR) core-flooding experiments on both water-wet and oil-wet Bentheimer sandstone samples under representative reservoir conditions (8 MPa, 333 K). These experiments enabled us to assess dynamic wettability changes and their impact on CO₂ residual trapping. Wettability evolution was quantified using wettability indices (WI), derived from NMR T1–T2 2D maps and T1/T2 ratios at each experimental stage. Additionally, CO₂ saturation and trapping efficiency were evaluated in the oil-wet sample to determine the influence of organic phases on storage capacity. Capillary pressure and relative permeability curves were also generated and validated against existing literature.
Results (100-200 words)
Our results show that exposure to supercritical CO₂ (scCO₂) significantly alters the wettability of initially water-wet sandstone, reducing its hydrophilicity from a strong water-wet state (WI = 1) to a weakly water-wet condition (WI = 0.22). This shift is attributed to the protonation of quartz surface silanol groups. NMR T2 distributions indicate that scCO₂ preferentially displaces water in larger pores (r > 1 µm), with minimal impact observed in smaller pores (r < 1 µm).
In comparison, the oil-wet sample exhibited a notably lower CO₂ trapping efficiency (18%) than the water-wet counterpart (31%), likely due to macroscopic flow channeling that facilitates CO₂ desaturation. Furthermore, while CO₂ trapping in oil-wet rock was predominantly in meso- and micropores, water-wet rock showed trapping mainly in macropores.
Additive Information (25-75 words)
This study provides a high-resolution dataset linking pore-scale wettability evolution and organic influence to CO₂ trapping capacity. These insights are crucial for improving predictive models and enhancing the reliability and scalability of industrial CGS operations in sandstone reservoirs.
Keywords: Carbon geo-sequestration; CO₂ wettability; Residual CO₂ trapping; NMR core-flooding; Wettability alteration, Capillary pressure, Relative permeability.