Multi-scale multi-dimensional microstructure imaging of oil shale pyrolysis using X-ray micro-tomography, automated ultra-high resolution SEM, MAPS Mineralogy and FIB-SEM

Title: Multi-scale multi-dimensional microstructure imaging of oil shale pyrolysis using X-ray micro-tomography, automated ultra-high resolution SEM, MAPS Mineralogy and FIB-SEM
Authors: Saif, T
Lin, Q
Butcher, AR
Bijeljic, B
Blunt, MJ
Item Type: Journal Article
Abstract: The complexity of unconventional rock systems is expressed both in the compositional variance of the microstructure and the extensive heterogeneity of the pore space. Visualizing and quantifying the microstructure of oil shale before and after pyrolysis permits a more accurate determination of petrophysical properties which are important in modeling hydrocarbon production potential. We characterize the microstructural heterogeneity of oil shale using X-ray micro-tomography (µCT), automated ultra-high resolution scanning electron microscopy (SEM), MAPS Mineralogy (Modular Automated Processing System) and Focused Ion Beam Scanning Electron Microscopy (FIB-SEM). The organic-rich Eocene Green River (Mahogany zone) oil shale is characterized using a multi-scale multi-dimensional workflow both before and after pyrolysis. Observations in 2-D and 3-D and across nm-µm-mm length scales demonstrate both heterogeneity and anisotropy at every scale. Image acquisition and analysis using µCT and SEM reveal a microstructure of alternating kerogen-rich laminations interbedded with layers of fine-grained inorganic minerals. MAPS Mineralogy combined with ultrafast measurements reveal mineralogic textures dominated by dolomite, calcite, K-feldspar, quartz, pyrite and illitic clays along with their spatial distribution, augmenting conventional mineral analysis. From high resolution Backscattered electron (BSE) images, intra-organic, inter-organic-mineral, intra- and inter-mineral pores are observed with varying sizes and geometries. By using FIB milling and SEM imaging sequentially and repetitively, 3-D data sets were reconstructed. By setting 3-D gradient and marker-based watershed transforms, the organic matter, minerals and pore phases (including pore-back artifacts) were segmented and visualized and the pore-size distribution was computed. Following pyrolysis, fractures from the mm-to-µm scales were observed with preferential propagation along the kerogen-rich laminations and coalescence leading to an interconnected fracture network. The application of these techniques to worldwide oil shale deposits will allow significant insights into estimating mechanical and chemical proprieties of oil shale formations for modeling and designing oil shale pyrolysis processes.
Issue Date: 20-Jun-2017
Date of Acceptance: 4-May-2017
URI: http://hdl.handle.net/10044/1/53192
DOI: https://dx.doi.org/10.1016/j.apenergy.2017.05.039
ISSN: 0306-2619
Publisher: Elsevier
Start Page: 628
End Page: 647
Journal / Book Title: Applied Energy
Volume: 202
Copyright Statement: © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Sponsor/Funder: PETROLEO BRASILEIRO S. A. PETROBRAS
Chevron Energy Technology Company
Maersk Oil Research & Technology Centre
Kuwait Oil Company (KOC)
Funder's Grant Number: N/A
N/A
Contract C- 8600003656
15051073
Keywords: Science & Technology
Technology
Energy & Fuels
Engineering, Chemical
Engineering
Oil shale
Pyrolysis
Multi-scale imaging
Microstructure
Organic matter
Pore structure
MULTIPLE-POINT STATISTICS
PORE-SPACE RECONSTRUCTION
GREEN RIVER
GEOLOGICAL-MATERIALS
MERCURY POROSIMETRY
ELECTRON-MICROSCOPY
KEROGEN PYROLYSIS
NANOMETER-SCALE
ORGANIC-MATTER
PARTICLE-SIZE
09 Engineering
14 Economics
Energy
Publication Status: Published
Open Access location: http://ac.els-cdn.com/S0306261917305512/1-s2.0-S0306261917305512-main.pdf?_tid=c85e57da-67ab-11e7-99ba-00000aacb362&acdnat=1499937495_bfddfea3f86b2c66e30552d32828f6a9
Appears in Collections:Earth Science and Engineering



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