Multi-scale Image-Based Pore Space Characterisation and Pore Network Generation: Case Study of a North Sea Sandstone Reservoir

In this paper we examine the pore space geometry and topology of a North Sea sandstone reservoir rock based on multi-scale scanning electron microscopy (SEM). The reservoir was subjected to extensive diagenesis which has resulted in a complex pore space with a wide range in pore sizes. We quantify the pore size and pore coordination number distributions and we find that the mean and standard deviation of the coordination number are power law functions of pore radius, where the scaling exponent varies from 0.3 to 0.5. We present a 2D stochastic algorithm to generate a pore network based on statistical information. The algorithm incorporates the concept of a weighted planar stochastic lattice which is a construction that naturally leads to scale-free character with power law behaviour. We validate the algorithm against SEM imaging by showing that it can reproduce the observed clustering and a realistic spatial distribution of pore space elements. We also try to explore the relationship between fluid flow properties of reservoir rock and 2D pore image features.