Multifractal analysis of the pore space of real and simulated sedimentary rocks

TL;DR

This study applies multifractal analysis to both real and simulated sedimentary rocks to understand pore space distribution and compares the realism of the simulation model with actual rock samples.

Contribution

It demonstrates that the Relaxed Bidisperse Ballistic Model can realistically simulate the multifractal pore structure of high porosity sedimentary rocks.

Findings

Both real and simulated rocks exhibit multifractal characteristics.

RBBDM effectively models high porosity sedimentary rock pore structures.

Real rocks show different multifractal spectra based on porosity levels.

Abstract

It is well known that sedimentary rocks having same porosity can have very different pore size distribution. The pore distribution determines many characteristics of the rock among which, its transport property is often the most useful. Multifractal analysis is a powerful tool that is increasingly used to characterize the pore space. In this study we have done multifractal analysis of pore distribution on sedimentary rocks simulated using the Relaxed Bidisperse Ballistic Model (RBBDM). The RBBDM can generate a $3-D$ structure of sedimentary rocks of variable porosity by tuning the fraction $p$ of particles of two different sizes. We have also done multifractal analysis on two samples of real sedimentary rock to compare with the simulation studies. One sample, an oolitic limestone is of high porosity (40%)while the other is a reefal carbonate of low porosity around 7%. $2-D$ sections of X-ray micro-tomographs of the real rocks were stacked sequentially to reconstruct the real rock specimens. Both samples show a multifractal character, but we show that RBBDM gives a very realistic representation of a typical high porosity sedimentary rock.