QUALITATIVE AND QUANTITATIVE INVESTIGATION OF MICROSTRUCTURES WITHIN POROUS ROCKS BY USING VERY HIGH RESOLUTION X-RAY MICRO-CT IMAGING

摘要

Today’s high-resolution X-ray CT with its powerful tubes and great detail detectability 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 in sediments – to name only a few. Especially spatial distribution of pores, mineral phases and fractures are important for the evaluation of reservoir properties. The possibility to visualize a whole plug volume in a non-destructive way is undoubtedly the most valuable feature of this type of rock analysis and is a new area for routine application of high resolution X-ray CT. All presented geological CT volume evaluations were performed with GE’s phoenix nanotom, a 180 kV/15 W nanofocus CT system tailored specifically for extremely high-resolution scans of samples weighing up to 3 kg with voxel-resolutions down to < 300 nm. 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.