Visualization of Soil Particle Pore after Infiltration of Slurry with Different Properties using X-ray Micro-CT

This study aims to reveal the mechanism of mud film formation when bentonite-based slurry and polymer-based slurry infiltrate into soil pore spaces by comparing the infiltration characteristics of both slurry with different properties. While most of the previous drilling slurry research has focused on macroscopic phenomena, it is important to closely observe microscopic phenomena in mud film formation to truly achieve the objective. Therefore, this research group succeeded in visualizing and quantifying the bentonite inside the specimen, which could not be seen by previous SEM studies, by a bentonite-based slurry infiltration test, X-ray CT imaging, and image analysis. In this study, a polymer-based slurry, which had not been investigated before, was also used. The results suggest that the total volume of bentonite may be smaller and the ratio of smaller clusters may increase with more viscous drilling slurry with higher CMC concentrations. In addition, while bentonite-based slurry reduces permeability through mud film and clusters inside the specimen, polymer-based slurry does not form a clear mud film and reduce permeability mainly through viscosity.