Nanometer-scale imaging and pore-scale fluid flow modeling inchalk Page: 5 of 16
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
50 Pixel value
Figure 5. Histogram displaying a high pore/grain contrast. Pore pixel values in 0-50 interval.
The sample studied, courtesy of ConocoPhillips, was a 1 in diameter Ekofisk plug with 29% He porosity and
permeability of 4 md. The sample was CT scanned using a Somatom HiQ medical CT scanner(Imm thick
slices, 133 kV, 120 mA) and a porosity distribution was determined. As seen in the four representative
crossections shown in Figure 6, the sample has a uniform porosity, except for a few mm-scale low porosity
regions apparent both on CT and visually. The mean CT measured porosity is 29% and in the low porosity
regions is 25%. The 6x4x2 mm sample selected for imaging was from a region with 29% porosity. The sample
was epoxy impregnated under vacuum, followed by up to 1400 psi pressure. It was polished following standard
thin section preparation techniques using up to 1 pm size diamond polishing disk. The chalk sample presented
a good contrast between the epoxy-filled pore space and the matrix, which allowed for secondary electron
imaging (SED detector) at 5 kV electron energy by using a 12 s scan, with minimal charging taking place (Fig.
7). The pixel resolution was 0.05 pm. The sections imaged were spaced 0.1 pm apart. To create 0.05 pm
cubic voxels, the number of 2D images was doubled by using interpolation between consecutive layers by a
spline-based algorithm TransformJ (Meijering, 2001). The good contrast allowed for direct thresholding of the
layers to generate a 3D binary image using ImageJ package. A 3D reconstruction of a subset of the binary data
is shown in Figure 8.
20 Porosity (%) 33
Figure 6. CT derived porosity crossections of chalk plug
Here’s what’s next.
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Tomutsa, Liviu; Silin, Dmitriy & Radmilovich, Velimir. Nanometer-scale imaging and pore-scale fluid flow modeling inchalk, article, August 23, 2005; Berkeley, California. (https://digital.library.unt.edu/ark:/67531/metadc893671/m1/5/: accessed May 22, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.