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This content will become publicly available on November 6, 2018

Title: The effects of burial diagenesis on multiscale porosity in the St. Peter Sandstone: An imaging, small-angle, and ultra-small-angle neutron scattering analysis

To examine the effects of burial diagenesis on heirarchical pore structures in sandstone and compare those with the effects of overgrowth formation, we obtained samples of St. Peter Sandstone from drill cores obtained in the Illinois and Michigan Basins. The multiscale pore structure of rocks in sedimentary reservoirs and the mineralogy associated with those pores are critical factors for estimating reservoir properties, including fluid mass in place, permeability, and capillary pressures, as well as geochemical interactions between the rock and the fluid. The combination of small- and ultra-small-angle neutron scattering with backscattered electron or X ray-computed tomographic imaging, or both, provided a means by which pore structures were quantified at scales ranging from aproximately 1 nm to 1 cm—seven orders of magnitude. Larger scale (>10 µm) porosity showed the expected logarithmic decrease in porosity with depth, although there was significant variation in each sample group. However, small- and ultra-small-angle neutron scattering data showed that the proportion of small-scale porosity increased with depth. Porosity distributions were not continuous, but consisted of a series of log normal-like distributions at several distinct scales within these rocks. Fractal dimensions at larger scales decreased (surfaces smoothed) with increasing depth, and those at smaller scales increasedmore » (surfaces roughened) and pores become more isolated (higher lacunarity). Furthermore, data suggest that changes in pore-size distributions are controlled by both physical (compaction) and chemical effects (precipitation, cementation, dissolution).« less
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3] ;  [3] ;  [1] ;  [4] ; ORCiD logo [5]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of Illinois, Champaign, IL (United States); Ernst-Moritz-Arndt-Univ., Greifswald (Germany)
  3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  4. Forschungszentrum Julich GmbH, Garching (Germany)
  5. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Marine and Petroleum Geology
Additional Journal Information:
Journal Volume: 92; Journal Issue: C; Journal ID: ISSN 0264-8172
Publisher:
Elsevier
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES
OSTI Identifier:
1435954