Dynamic Fluid Ingress Detection in Geomaterials using K-band Frequency Modulated Continuous Wave Radar

Jamie Blanche, Helen Lewis, Gary Douglas Couples, Jim Buckman, Nicolas Lenoir, Alessandro Tengattini, David Flynn

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
44 Downloads (Pure)


Frequency modulated continuous wave (FMCW) radar in the K-band has been shown to be an effective detector of geomaterial physical properties being highly sensitive to rock characteristics, particularly mineral composition and, for porous rock, variations in liquid water content. This research demonstrates that contrasts in FMCW return signals with time correlate with changes in geomaterial water content. FMCW signal returns were acquired for porous sandstone samples subjected to controlled water injection while also in a neutron beam, taking advantage of the well-known, and well-calibrated, attenuation of neutrons by hydrogen atoms for the water-containing porous sandstone samples. The sequential neutron tomographic images clearly show water moving up the sample with time while the FMCW observations show increases in radar reflection coefficient as a function of water position in the field of view. The observed FMCW detection of flood-front position is corroborated by the synchronous neutron tomographic images. We also observe repeatable variations in the radar reflection coefficient as a function of sample orientation during fluid injection, verifying that FMCW sensing offers real-time insight into the interactions between fluid movement and sample heterogeneity, via non-contact and non-invasive flood-front tracking. This research demonstrates that FMCW has potential to be a more accessible and easily deployable sensing modality than neutron tomography, enabling dynamic geomaterial testing to be conducted outwith the confines of the highly controlled laboratory environment required for neutron investigation.
Original languageEnglish
Pages (from-to)111027-111041
Number of pages15
JournalIEEE Access
Early online date12 Jun 2020
Publication statusPublished - 2020


  • Geologic measurements
  • microwave propagation
  • neutron tomography
  • non-destructive testing
  • radar applications
  • radar measurements
  • rock porosity

ASJC Scopus subject areas

  • Computer Science(all)
  • Materials Science(all)
  • Engineering(all)


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