Spatially Distributed Wettability Characterization in Porous Media

TL;DR

This paper introduces an advanced geometric algorithm for precise pore-scale contact angle measurement from micro-CT images, revealing wettability heterogeneity and improving understanding of multiphase flow in porous media.

Contribution

It presents a novel, accurate method for spatially-resolved wettability mapping and open-source tools, addressing limitations of averaged metrics in heterogeneous porous materials.

Findings

Revealed significant wettability heterogeneity in porous samples.

Showed limitations of average contact angle metrics.

Enabled better prediction of multiphase flow behavior.

Abstract

An enhanced geometric algorithm for automated pore-by-pore contact angle measurement from micro-CT images, is presented that achieves superior accuracy compared to existing methods through robust fluid-fluid and solid-fluid interface extrapolation. Using this high resolution data, we generate spatially distributed contact angle maps that reveal previously hidden wettability heterogeneity. Our analysis of mixed-wet systems demonstrates the severe limitations of averaged metrics: a sample with a mean contact angle of 64.7 degrees, conventionally classified as uniformly weakly water-wet, exhibits 40% of its pore space in the intermediate-wetting regime (70-110 degrees). This heterogeneity explains the presence of minimal surface interfaces and fundamentally different pore-filling mechanisms operating within the same sample. By providing open-source tools for spatially-resolved wettability characterization, this work enables more accurate predictions of multiphase flow behavior in heterogeneous porous materials, essential for optimizing subsurface energy storage and recovery processes.