Using X-ray microtomographic imaging to conduct fluid flow simulations on porous media

Abstract

In recent years, X-ray micro-computed tomography (μCT) has become an important and useful tool for characterizing the 3-D internal microstructure of porous media. Although the materials used in different fields of study will have varying compositions, the methods and techniques utilized in μCT are very similar. The aim of this presentation is to identify these similarities by comparing a master's thesis study dealing with the permeability of a sample composed of FeS melt and solid silicate to studies done in the petroleum industry on reservoir rocks.

The purpose of the master's thesis study was to test the hypothesis that shear deformation enhances the connectivity and permeability of Fe-S melt within a solid silicate (olivine) matrix. A 250 ton hydraulic press was used to heat and torsionally deform the sample through six steps of 180° rotation, while μCT was used to obtain in-situ 3-dimensional images of the sample at each step. The resulting digital volumes were processed and permeability simulations utilizing the lattice Boltzmann method were performed to determine the effect of shear deformation on connectivity and permeability within the sample.

The image acquisition, image processing, and data analysis techniques utilized in this study are very similar to those used in the petroleum industry. The major image processing technique performed on the digital volumes in this work was binarization, wherein the melt (fluid) and non-melt (matrix) are identified and segmented (i.e. separated). This same process of segmentation is conducted on digital volumes of reservoir rocks obtained via μCT, although the phases are different (e.g. cement, oil, gas, brine, and/or open pore space). Also similar to this work is that μCT images of reservoir rocks can be used to determine the porosity, pore connectivity, and permeability of a sample via fluid flow simulations, with quantitative results that can be obtained utilizing techniques such as the lattice Boltzmann method. The main goal of μCT use in the petroleum industry is to aid in predicting the producibility of a reservoir pay zone. μCT has proven to be a valuable tool for determining the properties of porous media, no matter the composition or end goal.

AAPG Datapages/Search and Discovery © 2014 Pacific Section AAPG, SPE and SEPM Joint Technical Conference, Bakersfield, California, April 27-30, 2014