Nearly all pathways identified by the Intergovernmental Panel on Climate Change that limit climate-change induced temperature rise to less than 2^oC rely on large-scale diversion of carbon emissions away from the atmosphere and instead into permanent storage.

Geologic carbon sequestration involves the capture of emitted carbon dioxide (CO₂) from point source emitters (or potentially, directly from the atmosphere) followed by injection into porous rocks deep underground. In order to be able to predict where the CO₂ will go once it’s been injected– and to design safe strategies to prevent the buoyant CO₂ from bubbling back up to the surface– we need to understand how the fluid CO₂ moves through the tortuous pore spaces of the rocks, on length scales ranging from the size of individual bubbles to the size of geologic formations.

At the ANU National Laboratory for X-ray MicroComputed Tomography (CTLab), we use X-ray microscopy to map mineral and fluid distributions in three dimensions during high-pressure injections of CO₂ into rock cores. I will provide an overview of this X-ray imaging technology, as well as what we have learned about multiphase fluid dynamics from our experiments, and how we can use this knowledge to help design safe and efficient CO₂ injection and storage strategies.