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

Autor: Tarik Saif, Qingyang Lin, Martin J. Blunt, Branko Bijeljic, Alan R. Butcher
Přispěvatelé: PETROLEO BRASILEIRO S. A. PETROBRAS, Chevron Energy Technology Company, Maersk Oil Research & Technology Centre, Kuwait Oil Company (KOC)
Rok vydání: 2017
Předmět:
Technology
Engineering
Chemical
Energy & Fuels
Scanning electron microscope
020209 energy
Mineralogy
02 engineering and technology
Management
Monitoring
Policy and Law
010502 geochemistry & geophysics
PORE-SPACE RECONSTRUCTION
01 natural sciences
Focused ion beam
09 Engineering
Engineering
MERCURY POROSIMETRY
0202 electrical engineering
electronic engineering
information engineering
Anisotropy
Microstructure
Quartz
KEROGEN PYROLYSIS
14 Economics
0105 earth and related environmental sciences
Oil shale
ELECTRON-MICROSCOPY
Science & Technology
Energy
NANOMETER-SCALE
Mechanical Engineering
Petrophysics
Building and Construction
Porosimetry
PARTICLE-SIZE
ORGANIC-MATTER
GREEN RIVER
General Energy
Multi-scale imaging
Organic matter
Pore structure
Pyrolysis
MULTIPLE-POINT STATISTICS
GEOLOGICAL-MATERIALS
Zdroj: Applied Energy. 202:628-647
ISSN: 0306-2619
DOI: 10.1016/j.apenergy.2017.05.039
Popis: 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.
Databáze: OpenAIRE
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