Application of Avizo Fire image processing for substances investigation inside porous medium


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By Alexander N. Nadeev (Schlumberger Moscow Research)

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Application of Avizo Fire image processing for substances investigation inside porous medium

  1. 1. Application of Avizo Fire imageprocessing for substances investigation Schlumberger Publicinside porous medium A. Nadeev, I. Yakimchuk, D. Mikhailov, E. Chuvilin, D. Koroteev, D. Korobkov, V. Shako Schlumberger Moscow Research1 / 13 SMR
  2. 2. X-ray attenuation bases The value of linear attenuation coefficient (LAC) of every substance depends on chemical composition, material density and X-ray radiation energy:   m (E) Schlumberger Public μm – mass attenuation coefficient at given X-ray radiation (E) energy (cm2/g), ρ – material density (g/cm3) I  I 0e  l I – X-ray radiation intensity after l length propagation, I0 – initial X-ray radiation intensity, μ – linear attenuation coefficient (cm-1), l – length of radiation propagation (cm) The best solutions is application of X-ray contrast agents – chemical composition change!2 / 13 SMR
  3. 3. Aims Exciting micro-CT images Additional/new measurements • X-ray micro-CT based approach development for investigation of Schlumberger Public phases distribution inside porous space of rock samples • identification of possible ways to improve X-ray contrast of phases (ice, gas hydrate, clays and etc.) in porous medium: to avoid disturbance of distribution or phases properties change • application of X-ray contrast agents for distribution analysis of phases in 2D and 3D micro-CT images using Avizo Fire software3 / 13 SMR
  4. 4. Micro-CT experiment• SkyScan-1172 (Bruker micro-CT, Belgium) micro-CT scanner • Parameters of our experiments: • Source: 100 kV &100 A • Filter: built-in Al+Cu Sample Schlumberger Public • Pixel size resolution: 3.0-3.5 m • 1200-1800 angular projections (3600)• Modified Feldkamp reconstruction algorithm (Nrecon with InstaRecon engine, GPU base reconstruction)• Image processing and visualization: Avizo Fire 7.0.0, CTAn, CTVox• Special stages: SkyScan micro-CT cooling stage to investigate ice saturated samples SkyScan-1172 micro-CT scanner equipped by cooling stage• Artificial and natural sandstones: • Samples contains ice and/or clay phases 4 / 13 SMR
  5. 5. Method for contrast improvement: ice saturation with ions ofheavy metal Cooling chamber, T = - 6oC Sample Diffusion coefficient of Schlumberger Public Pb(NO3)2 in ice is 0.2×10-5 cm2/sec-1 (Fick’s Law) Ice which contains ions of heavy metal 1% Pb(NO3)2 Appropriate time for saturation of frozen sample with Pb2+ ions is about 1 week5 / 13 SMR
  6. 6. Influence of heavy metal ions on ice visualization  spatial resolution is 3.2 Schlumberger Public m/pixel  average grain size is 300 m Micro-CT images of ice contained sand samples without contrast agent (a) and saturated with lead ions (b)6 / 13 SMR
  7. 7. Influence of heavy elements on clay visualization a b Schlumberger Public A+B- +C+D- ToC  spatial resolution is A+1-xC+xB- 3.2 m/pixel A+B- – clay and C+D- – contrast agent compounds  5% water based clay solution Distribution of modified clay in dried (a) and wet sample (b)7 / 13 SMR
  8. 8. Application of Avizo Fire filters for reconstructed slice of sand sample Schlumberger Public Experimental data Non-Local Means Edge-Preserving 8 / 13 SMR
  9. 9. Image segmentation using Avizo Fire Schlumberger Public Non-Local Means Edge-preserving9 / 13 SMR
  10. 10. Avizo Fire permeability calculation (XLab Hydro application) “Experimental” permeability in z direction for the model 400x400x200 voxels: Schlumberger Public  Permeability of rock is 667 mD  Permeability of ice saturated rock is 83 mD10 / 13 SMR
  11. 11. Ice distribution analysis Cutting from 3D image of sample Schlumberger Public Sample length, µm Pore size distribution for two cases (15% of humidity): rock matrix porosity and remain porosity Ice content, % taking into account the pore iceCylinder height = 6 mm, diameter = 3 mm11 / 13 SMR
  12. 12. Clay distribution analysis 1 23 4 1 23 4 0.12 1 0.9 Concetration of clay 0.1 3 0.8 Void fraction, % 0.08 0.7 0.6 0.06 0.5 0.4 0.04 0.3 Schlumberger Public 0.02 0.2 0.1 0 0 0 1 2 3 4 5 6 0 1 2 3 4 5 6 Length of sample, mm Length from inlet, mm 1 2 3 4 Spatial resolution is 3.2 m/pixel  There is a damage in sample inlet 12 / 13 SMR
  13. 13. Summary• Special approaches for improvement X-ray contrast of phases inside rock porous medium were developed: clay contrasting is based on ions interchange/ adsorption reactions, for ice visualization is applied ions solid state diffusion Bruker micro-CT scanner SkyScan 1172 equipped with cooling stage can be used for Schlumberger Public• investigation unconsolidated or low consolidated reservoir rock, where ice in porous medium plays role of natural cement• Unconsolidated rock properties such as: porosity, pore size distribution, residual water saturation and, finally, building adequate 3D digital model can be achieved in case of correct matrix-ice segmentation due to Avizo Fire software application• XLab Hydro extension of Avizo Fire 7.0.0 can be applied for permeability calculation of phases invaded rock13 / 13 SMR