High pressure-elevated temperature x-ray micro-computed tomography for subsurface applications.

Area of Science:

• Geosciences and Engineering
• Pore-scale physics and chemistry
• Subsurface process modeling

Background:

• Subsurface processes like fluid flow and mineral interactions occur at the micrometer scale.
• Traditional 2D experiments provide limited insights into these complex 3D phenomena.
• Subsurface conditions involve high pressures and elevated temperatures (HPET) that significantly alter physical and chemical processes.

Purpose of the Study:

• To describe the workflow, equipment, and apparatus design for HPET-μCT experiments.
• To review existing literature on HPET-μCT applications in subsurface science.
• To provide a guideline for setting up HPET-μCT experiments and understanding their capabilities.

Main Methods:

• Utilizing X-ray micro-computed tomography (μCT) to visualize micrometer-scale pore structures in 3D.
• Applying high-pressure and elevated temperature (HPET) conditions to μCT experiments to simulate subsurface environments.
• Analyzing experimental data to understand physical, chemical, and mechanical processes at the pore scale.

Main Results:

• HPET-μCT overcomes the limitations of 2D experiments by providing realistic 3D observations of pore-scale phenomena.
• HPET conditions significantly influence processes such as gas density, wettability, and reaction kinetics.
• The study reviews applications including CO2 geo-sequestration, oil recovery, gas hydrate formation, and hydrothermal deposition.

Conclusions:

• HPET-μCT is an indispensable tool for investigating subsurface micrometer-scaled processes under realistic conditions.
• The technique yields vital data for accurate large-scale reservoir models.
• The use of HPET-μCT is expected to expand rapidly in subsurface engineering and sciences.