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Title: Resolution dependence of petrophysical parameters derived from X-ray tomography of chalk

X-ray computed tomography data from chalk drill cuttings were taken over a series of voxel dimensions, ranging from 320 to 25 nm. From these data sets, standard petrophysical parameters (porosity, surface area, and permeability) were derived and we examined the effect of the voxel dimension (i.e., image resolution) on these properties. We found that for the higher voxel dimensions, they are severely over or underestimated, whereas for 50 and 25 nm voxel dimension, the resulting values (5%–30% porosity, 0.2–2 m{sup 2}/g specific surface area, and 0.06–0.34 mD permeability) are within the expected range for this type of rock. We compared our results to macroscopic measurements and in the case of surface area, also to measurements using the Brunauer-Emmett-Teller (BET) method and found that independent of the degree of compaction, the results from tomography amount to about 30% of the BET method. Finally, we concluded that at 25 nm voxel dimension, the essential features of the nanoscopic pore network in chalk are captured but better resolution is still needed to derive surface area.
Authors:
; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø (Denmark)
  2. European Synchrotron Research Facility, Grenoble (France)
  3. Nano-Science Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø (Denmark)
  4. Mærsk Oil and Gas A/S, Copenhagen K (Denmark)
Publication Date:
OSTI Identifier:
22311218
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CALCITE; CAPTURE; COMPUTERIZED TOMOGRAPHY; LIMESTONE; PERMEABILITY; POROSITY; RESOLUTION; SPECIFIC SURFACE AREA; SURFACE AREA; X RADIATION