InterPore2025

Dual Energy X-Ray CT for Improving the Characterization of Clay-Rich Sandstones

21 May 2025, 14:50

15m

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

Speaker

Cinar Turhan (The University of Texas at Austin)

Description

Dual-energy computed tomography (DECT), a non-destructive characterization method of geological samples, has been used for estimating the effective atomic number ($Z_{eff}$), and the density (ρ) of the components of a sample. These estimates require calibration using three materials with known intensities as well as air – typically surrounding the sample – within the scan range, resulting in four reference points at two different X-ray energies. This type of setup is not standard practice, but we argue that it should be.

CT data always contains noise. Incorporating a Monte Carlo (MC) approach into this method quantifies the uncertainty caused by the noisy nature of CT scans, and allows for finding a solution where noise would prevent finding an exact solution. A study by Victor et al. (2017) showed that this method can be used in carbonate samples to improve the estimation of petrophysical properties; however, its application remains untested in clay-bearing sandstones and other rock types. In this study, we validate the application of MC-based inversion of $Z_{eff}$ and ρ in clay-rich sandstones and assess its effectiveness. We focus in particular on improving the saturation estimates, which are often unreliable for clay-rich materials, as well as distinguishing clay types.