Systematic multiscale characterization and statistical analysis of mudrock microstructures by scanning SAXS and WAXS microscopy

Marine Geoscience and Energy Resources, vol. 193, pp. 207834

Abstract

We establish a multiscale characterization workflow enabling accurate representations of mudrock microstructures by combining spatially resolved synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) microscopy with statistical analysis. High-throughput spatially resolved SAXS and WAXS measurements were performed on a 25 μm thick section of a mudrock sample from the Eagle Ford formation. A high (microscopic, μm 2 ) scanning resolution was achieved, and performing thousands of consecutive measurements a representative ( mm 2 ) sample area was systematically probed. We quantified key microstructural parameters including the mineralogy, nano pore (6 – 202 nm) porosity, pore orientation and their spatial variation, finding a heterogeneous microstructure. Performing hierarchical clustering we demonstrate that the SAXS data can be clustered macroscopically into 4 microstructural groups each exhibiting statistically significantly different properties: fossils and grains, nodules, matrix, and veins. We then used image analysis to characterize the shape, size, and distribution characteristics of the 4 groups. To facilitate further use of the dataset, generic distribution functions were fitted to all the parameters obtained, potentially allowing easy incorporation into pore-scale models in future research.

Authors 11

1. L. Leu

   Imperial College London · Delft University of Technology

   Affiliation as printed

   Department of Earth Science and Engineering, Imperial College London, UK

   Reactor Institute Delft, Delft University of Technology, Mekelweg 15, Delft, The Netherlands

2. Peiter Bertier
   Affiliation as printed

   Dynchem Scientific Instruments, Kronprinzenstrasse 5, Aachen, Germany

3. H. Claes Aachen Clay and Interface Mineralogy (CIM)

   RWTH Aachen University

   Affiliation as printed

   Clay and Interface Mineralogy, RWTH Aachen, Germany

4. A. Busch

   Heriot-Watt University

   Affiliation as printed

   Lyell Centre for Marine and Earth Science and Technology, Heriot-Watt University, UK

5. A. Georgiadis

   Imperial College London · Shell (Netherlands)

   Affiliation as printed

   Department of Chemical Engineering, Imperial College London, UK

   Shell Global Solutions International B.V., Kessler Park 1, 2288 GS Rijswijk, the Netherlands

6. A. Diaz

   Paul Scherrer Institute

   Affiliation as printed

   PSI Center for Photon Science, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland

7. V. Luetz-Bueno
8. H. Ott

   Montanuniversität Leoben · Imperial College London

   Affiliation as printed

   Department Geoenergy, Montanuniversität Leoben, 8700 Leoben Austria

   Department of Chemical Engineering, Imperial College London, UK

9. J. Klaver Aachen Map – Microstructure and Pores GmbH

   Microstructure and Pores

   Affiliation as printed

   MaP - Microstructure and Pores GmbH, Lochnerstrasse, Aachen, Germany

10. J. Schmatz Aachen Map – Microstructure and Pores GmbH

    Microstructure and Pores

    Affiliation as printed

    MaP - Microstructure and Pores GmbH, Lochnerstrasse, Aachen, Germany

11. M.J. Blunt

    Imperial College London

    Affiliation as printed

    Department of Earth Science and Engineering, Imperial College London, UK