Quantitative Investigation of Microstructures within Porous Rocks by Using Very High Resolution X-ray Micro-CT Imaging

Today’s high-resolution X-ray CT lends itself naturally to geological and petrological applications. Those include the non-destructive interior examination and textural analysis of rocks and their permeability and porosity, the study of oil occurrences in reservoir lithologies, and the analysis of morphology and density distribution – to name only a few. Especially spatial distribution of pores, mineral phases and fractures are important for the evaluation of reservoir properties. All presented geological CT volume evaluations were performed with GE’s phoenix nanotom, a 180 kV/15W nanofocus CT system for extremely high-resolution.

In our first sample we will show a typical reservoir rock scanned with 1 µm voxel size to characterize the pore space and to extract information about the distribution of mineral components. The segmented in-situ porosity could be easily used for fluid flow modelling purposes, to predict permeability and complex flow processes within these structures.

Next, two very porous pyroclastic rock samples have been examined at a resolution of 1 and 5 µm. One data set has been analysed with the Avizo software tool XLab Hydro. Besides permeability tensor, porosity and pressure drop, the resulting velocity field of the fluid particles can be directly visualized whereas the colour mapping indicates the velocity’s magnitude.