From Pore Structure to Mixing and Relative Permeability in Carbonates
Martin J. Blunt, Branko Bijeljic, Oussama Gharbi, and Peyman Mostaghimi
Department of Earth Science and Engineering, Imperial College London, UK
We have used synchrotron radiation to generate three-dimensional images of a variety of carbonate samples. A selection of the samples studied are shown in Figure 1: the image resolution is approximately 8 mm, while the samples have a diameter of approximately 5 mm. The images are first binarized into pore and grain. We employ a network extraction algorithm (Dong and Blunt, 2009) to determine topological properties of the pore space, such as average coordination number, as well as to produce a network for two-phase pore-scale modelling.
The study has some major limitations, of which the most significant is ignoring micro-porosity. The images do not presently have sufficient resolution to capture much of the pore space: either a higher resolution scan, or a different method (such as FIB/SEM) is required. The network analysis needs to account for flow in both the larger pores and micro-porosity, which should enable a more convincing prediction of the water relative permeability (the micro-porosity is likely to be largely or completely water filled during a displacement). To validate this approach we should compare network predictions with measurements on the same core samples.
AAPG Search and Discovery Article #120034©2012 AAPG Hedberg Conference Fundamental Controls on Flow in Carbonates, Saint-Cyr Sur Mer, Provence, France, July 8-13, 2012