Electromagnetic sensing of materials
Creators: name: Kuznetcov, Ilia
Publisher: name: Schulich School of Engineering
Year: 2023
Subjects: subject: Dynamic electromagnetic sensing
subject: electric conductivity
subject: porous media
subject: electrode polarization
subject: frequency and time domain inversion
subject: nanosuspensions
subject: immiscible displacement
subject: dielectric spectroscopy
subject: impedance spectroscopy
subject: complex dielectric permittivity
subject: Geophysics
subject: FOS: Earth and related environmental sciences
subject: Remote Sensing
subject: Chemistry--Radiation
subject: Engineering--Chemical
subject: Engineering--Electronics and Electrical
subject: Materials Science
subject: Engineering--Petroleum

description: The ability to predict propagation of electromagnetic waves through matter is of great importance in various industries, that include medicine, food, geophysics, oil and gas and others. Polarizability and conductance, that may also be referred to as dielectric permittivity and electric conductivity, are the two most important properties that govern this phenomenon. These basic properties often depend on frequency of the excitation field, water content, concentrations of charged species, spatial distribution of inclusions and their sizes, surface charge etc. There has been an abundance of dielectric property measurements of various physicochemical systems reported in the literature. However, there has been a lack of measurements reported that would concern isolation of an electrode polarization effect, which manifests itself in a build up of charged species near electrodes at low frequencies. Also, there has been a shortage of studies performed in dynamic systems, that involve measurements of reflection and transmission scatter parameters, and dielectric properties at radio frequencies during immiscible displacement floods in porous media. Frequency broadband impedance measurements of 9 ferroelectric and magnetic nanosuspensions were performed. Relative dielectric constant and conductivity frequency spectra were extracted using a parallel resistor-capacitor equivalent circuit. Tikhonov’s regularization was used to fit the extracted dielectric spectra by the continuous relaxation Kramer-Krönig model. The electrode polarization effect was removed by zeroing out the two slowest peaks in the resulting time domain relaxation amplitude responses. The effective medium theory, the Gouy-Chapman-Stern-Graham model and zeta-potential measurements were used to validate the proposed electrode polarization removal method. Water saturation axial profiles and dielectric properties were monitored via electromagnetic sweeps during oil and water floods of confined sands. Breakthrough of advancing and trailing fronts and in-situ emulsification were captured during the imbibition (water) floods. Pressure distributions along sand packs and dynamic capillary pressure curves were calculated for some drainage and imbibition floods. Series, parallel and semi-disperse mixing models were fitted to the extracted dielectric spectra. In the present work, several applications of the novel electromagnetic sensing method have been demonstrated to dynamically monitor dielectric properties in nanosuspensions and their spatial distributions during immiscible displacements through saturated confined sand packs.