Our novel procedure of injecting oil after reactive transport has revealed previously unidentified (ghost) regions of partially-dissolved grains of carbonate rock. X-ray micro-tomography and FIB-SEM techniques were used to identify and resolve these ghost regions in three-dimensions at the nm- to µm-scale. Considering the solid part of the ghost regions as macro (bulk) pore space can result in the overestimation of porosity and permeability predicted from segmented X-ray tomographic images.
How Amira-Avizo Software is used
The tomograms were reconstructed using proprietary software provided by Zeiss and processed using Avizo 9 software unless otherwise specified. The tomograms were pre-processed to remove distorted outer regions. The stitched image (5 µm voxel size) of the dry rock sample was filtered using a non-local means edge preserving filter. This was then segmented into two phases (solid and pore space) using a seeded watershed algorithm based on the gray-scale gradient and gray-scale intensity of each voxel.