By Gerhard Zacher (GE Sensing & Inspection Technologies)

1. Evaluation of Rock Properties and Rock
Structures in the µ-range with sub-µ X-ray
Computed Tomography
Avizo Meeting, Bordeaux, May 31, 2012
Gerhard Zacher1, Matthias Halisch², Thomas Mayer1
1) GE Sensing & Inspection Technologies, Wunstorf, Germany
²) Leibniz Institute for Applied Geophysics, Hannover, Germany

2. Content
1. Introduction & Fundamentals
2. nanotom CT / resolution comparison
3. Scan results for geological samples
4. Conclusion & Outlook
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3. Introduction & Fundamentals
X-ray tubes Microfocus - nanofocus
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4. Introduction & Fundamentals
Requirements
Geometry and Resolution
M=FDD/FOD
U=(M-1)F (on the detector)
Vx=P/M
detector pixel P<< U
F predominates resolution
detector pixel P >> U
Pixel- / Voxelsize predominates resolution
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5. Introduction & Fundamentals
Resolution and Detail Detectability
Detail detectability of the nanofocus tube
Conclusion:
detail detectability
is no measure 5 µm 5 µm
for sharpness
500 nm 500 nm
Focal Spot ≈2.5 µm ≈ 0.8 µm
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6. Introduction & Fundamentals
Resolution and Detail Detectability
Resolution
Focal spot size influence:
≈2.5 µm ∅ ≈1.5 µm ∅ ≈0.8 µm ∅
2 µm bars 2 µm bars 0.6 µm bars
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7. Content
1. Introduction & Fundamentals
2. nanotom CT / resolution comparison
3. Scan results for geological samples
4. Conclusion & Outlook
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8. Nanotom CT / resolution comparison
nanotom m
ultra-high resolution
nanoCT system
X-ray tube:
nanofocus < 800 nm spot size
180 kV / 15 W, tube cooling
X-ray detector:
Cooled flat panel, 7.4 Mpixel,
11 Mpixel virtual detector
100 µm pixel size
Manipulator:
5 axis stepper motors,
granite-based,
high-precision air bearing
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9. Nanotom CT / resolution comparison
Principle of CT
Acquisition
of projections
during step-by-step
rotation by 360°
Steps < 1°
The acquisition of radiographic data is the
elementary measuring process in CT
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10. nanotom CT / resolution comparison
Principle of CT: Reconstruction Method
Example: spark plug
projection inversion log + filter line back-projection
profile
Acquisition of 600 projections 600 back projections 3D visualization
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11. Nanotom CT / resolution comparison
microfocus nanoCT microCT
CT
vs.
nanofocus
CT
of a dried
fern
Image resolution:
nanoCT: < 1 µm microCT: ≈4 µm 11 /
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12. Nanotom CT / resolution comparison
nanofocus
CT
of a dried
fern
• Example for resolving smallest features
≤ 1µm 12 /
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13. Content
1. Introduction & Fundamentals
2. nanotom CT / resolution comparison
3. Scan results for geological samples
4. Conclusion & Outlook
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14. Scan data of geological samples
Bentheimer Bentheimer sandstone
sandstone
(Ø 5 mm)
Vx = 1 µm
A
A
B
B
1 mm
3D volume of CT scan. Quartz (grey), (A) clay (brown),
(B) feldspar (blue) and high absorbing minerals (red). 14 /
Right: pore space is separated (green) GE /

15. Scan data of geological samples
Bentheimer Bentheimer sandstone
sandstone
(Ø 5 mm)
Vx = 1 µm
Electron microscope images of clay aggregation (left)
and highly weathered feldspar (right) 15 /
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16. Scan data of geological samples
Bentheimer Bentheimer sandstone
sandstone
(Ø 5 mm)
Vx = 1 µm
feldspar
1 mm
Comparison of CT result (left) and thin section (right).
Histogram shows several peaks for different phases 16 /
(air, clay (Illite), quartz, feldspar, denser minerals. GE /

17. Scan data of geological samples
Bentheimer Bentheimer sandstone
sandstone Increasing inhomogeneity of samples
(Ø 5 mm)
Vx = 1 µm
Representative?
Scale
1 mm
problem?
For different sandstones (Bentheimer, Oberkirchener
and Flechtinger) porosity has been evaluated by 17 /
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different methods. Range differs a lot.

18. Scan data of geological samples
Bentheimer Bentheimer sandstone
sandstone Bentheimer Sandstone Flechtingen Sandstone
(Ø 5 mm)
Vx = 1 µm
1 mm
Mittlere Porosität: ~ 22.5 % Mittlere Porosität: ~ 7 %
Repräsentatives Scan-Volumen: Repräsentatives Scan-Volumen:
1000x1000x1000 Voxel > 1750x1750x1750 Voxel
Porosity (CT) with respect to volume size for different 18 /
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sandstones

19. Scan data of geological samples
Bentheimer Bentheimer sandstone
sandstone outlook
(Ø 5 mm)
• Further linking CT informationen to rock physik:
• inner surface
Vx = 1 µm • pore size distribution / NMR
Avizo • Preparation of CT data for modelling (pore scale)
fluid flow
simulation
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20. Scan data of geological samples
Bentheimer Bentheimer sandstone
sandstone video
(Ø 5 mm)
Vx = 1 µm
Avizo
fluid flow
simulation
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21. Scan data of geological samples
pyroclastic
rock
(Ø 1 mm)
zoomed
Vx = 1 µm area
yz-slice
1 mm
3mm
yz-slice with different grains with high porosity or
fractures and bigger pores
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22. Scan data of geological samples
pyroclastic
rock
(Ø 1 mm)
Vx = 1 µm
yz-slice
1 mm
3mm
Zoom into yz-slice with measurement of thin wall: 1.8 µm
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23. Scan data of geological samples
Etna
pyroclastic
rock
(fresh’11)
(Ø 10 mm)
Vx = 5 µm
xy-slice
1 mm
3mm
xy-slice through 5x5x5mm cube used later for flow
simulation
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24. Scan data of geological samples
Etna Etna pyroclastic rock
pyroclastic
rock
(fresh’11)
(Ø 10 mm)
Vx = 5 µm
3D volume
1 mm
3mm
The surface is composed of 18 Mio. faces and
represents the stone matrix. Shadows enhance the 24 /
spatial impression. GE /

25. Scan data of geological samples
Etna Etna pyroclastic rock
pyroclastic
rock
(fresh’11)
(Ø 10 mm)
Vx = 5 µm
Avizo
fluid flow
simulation
1 mm
3mm
The colored volume rendering shows the velocity’s
magnitude within the pore space. The particle plot 25 /
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shows the actual vector field using cones.

26. Scan data of geological samples
Etna Etna pyroclastic rock
pyroclastic
rock
(fresh’11)
(Ø 10 mm)
Vx = 5 µm
Avizo
wall
thickness
1 mm
3mm
The pore space is visualized with volume rendering.
The matrix’ thickness has been calculated and is 26 /
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visualized on the surface.

27. Scan data of geological samples
Etna Etna pyroclastic rock
pyroclastic
rock
(fresh’11)
(Ø 10 mm)
Vx = 5 µm
Avizo
fluid flow
simulation
1 mm
3mm
The color slice intersects the velocity field calculated
with XLab Hydro and visualizes the vector field. 27 /
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Colors give the velocity’s magnitude.

28. Scan data of geological samples
3D view of a
Nummulite
Lower Eocene
53 million
years old
(Ø 2 mm)
Courtesy of
R. Speijer, K.U.
Leuven, Belgium
Vx = 1 µm
1 mm
3mm
Transparent 3D view
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29. Scan data of geological samples
3D view of a
Nummulite
Lower Eocene
53 million
years old
(Ø 2 mm)
Courtesy of
R. Speijer, K.U.
Leuven, Belgium
Vx = 1 µm
1 mm
Sliced 3D view to show the delicate internal structures
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30. Scan data of geological samples
Slice view of a zoomed
Nummulite area
Lower Eocene
53 million
years old
(Ø 2 mm)
Courtesy of
R. Speijer, K.U.
Leuven, Belgium
Vx = 1 µm
1 mm
Xy slice through center plain
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31. Scan data of geological samples
Slice view of a
Nummulite
Lower Eocene
53 million
years old
(Ø 2 mm)
Courtesy of
R. Speijer, K.U.
Leuven, Belgium
Vx = 1 µm
1 mm
3mm
Zoomed xy slice through center plain with measured pore
2.3 µm
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32. Content
1. Introduction & Fundamentals
2. nanotom CT / resolution comparison
3. Scan results for geological samples
4. Conclusion & Outlook
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33. Conclusions
• State of the art high resolution tube based X-ray CT with
the phoenix nanotom offers
• Comparable (or higher) spatial resolution to SRµCT
setups due to nanofocus tube (ease of use, lower cost
and faster analysis)
• Wide variety of geological samples can be analysed
• Data of a whole 3D volume offers numerous qualitative
AND quantitative interpretations
• New insights in rock materials for geo science
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34. Outlook
• More quantitative data analysis (like permeability, particle
size distribution, density distribution, …)
• More input from geoscientists to better generate the
potential of nanofocus X-ray CT
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35. Contact and further information:
www.phoenix-xray.com
or
www.ge-mcs.com/phoenix
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