Speaker
Description
High-resolution X-ray Computed Tomography (XRCT) is a powerful tool for investigating phase differences in rock samples, such as pores and solids. Despite significant differences in bulk density or porosity between calcite and dolomite, their similar X-ray absorption coefficients lead to comparable gray-scale intensities, making phase differentiation challenging. Overcoming this limitation is essential for interpreting mineralogical transitions in geochemical experiments within a location-dependent volume.
This study addresses the challenge of visualizing and segmenting calcite and dolomite phase differences under hydrothermal experimental conditions by combining high-resolution XRCT and spectral tomography.
Dolomitization was replicated in laboratory conditions using hydrothermal reactors at 200°C with a Mg- and Zn-enriched reactive fluid. The fluid composition included MgCl2, CaCl2, ZnCl2, and NaCl, mimicking natural hydrothermal environments. Samples were treated for two weeks in static conditions with a high fluid-to-rock ratio, ensuring the reaction was not fluid-limited. Conventional XRCT workflows, which record the total intensity of the incident beam, were unable to differentiate calcite and dolomite due to their similar absorption properties. By integrating spectral tomography, which detects the energy of each photon separately, we were able to overcome these limitations and achieve clear differentiation between the two phases.
Using the combined approach of high-resolution XRCT and spectral tomography, we successfully distinguished phase differences between calcite and dolomite, which were undetectable with standard imaging methods. This approach enabled visualization of subtle mineralogical changes induced by hydrothermal treatment.
The successful application of this combined workflow results in the current state of sophisticated multiphase segmentation in four different reservoir rocks, enabling the evaluation of changes in key physical properties—such as elastic, hydraulic, thermal, and electrical properties—during hydrothermal experiments.
This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 101005611 for Transnational Access conducted at DMEX-UPPA-FRANCE.
| Country | Germany |
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