RESULTS OF A LABORATORY STUDY HIGHLIGHTING THE POTENTIAL OF INTEGRATED P-WAVE AND ELECTRICAL METHODS APPLICATION IN NEAR-SURFACE

Abstract

PreviousNext No AccessSymposium on the Application of Geophysics to Engineering and Environmental Problems 2014RESULTS OF A LABORATORY STUDY HIGHLIGHTING THE POTENTIAL OF INTEGRATED P-WAVE AND ELECTRICAL METHODS APPLICATION IN NEAR-SURFACEAuthors: Bilal HassanStephen ButtCharles HurichBilal HassanMemorial UniversitySearch for more papers by this author, Stephen ButtMemorial UniversitySearch for more papers by this author, and Charles HurichMemorial UniversitySearch for more papers by this authorhttps://doi.org/10.4133/SAGEEP.27-146 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Integrated near-surface geophysical surveys can improve shallow subsurface imaging. Inversion of joint P-wave and electrical resistivity data may offer a reliable tool for detailed near-subsurface mapping, especially for saturation effects. Findings/results of an integrated imaging laboratory study are reported. Monitoring/imaging of a controlled immiscible fluid-displacement through a porous medium was simulated at lab scale. The core/analogue for unconsolidated sediment was 0.5mm spherical glass bead-pack in 45cm section of a vertical transparent PVC tube with 5.09cm inner diameter circular section, i.e. a flow-cell system. Eight electrode pairs were attached along the flow-cell, spaced equally, with a 1MHz P-wave ultrasonic source/receiver sensor pair at midspan between electrode/channel 4 and 5, where channels are numbered 1-8 upward. DC resistance and ultrasonic P-wave data were acquired simultaneously for all channels as oil was displaced with brine against gravity, at constant head conditions, until after breakthrough. Three experiments with different initial/invading flow rates (fast, intermediate and slow) were performed. Ultrasonic P-wave arrival-time/velocity, instantaneous/integrated amplitudes and logarithmic values of electrical resistance were plotted against elapsed time for inferring/correlation. Apart from pure saturations, spatially and temporally localizable distinct interface/mixed-zone and associated fluid fronts were identified by juxtaposing ultrasonograms and electrical resistance variation data, consistently in all experiments. Velocity increased in the mixed-zone, compared to velocities measured in oil, but remained slower than that of the brine saturated zone. Lowest amplitudes were observed in the mixed-zone but amplitudes of brine were higher than those of oil. For higher invading fluid flow rates an early breakthrough was also deducible by observation of viscous fingering. Sensitivity of interfacial stability/degree of mixing to flow velocity/regime with interface evolving in time was evident. Efficient displacement with stable interface was observed and/or expected for slower flow rate. Inevitably, findings confirm integrated/innovative geophysical surveys more reliably map heterogeneous near-subsurface for addressing engineering/environmental problems i.e. monitoring infrastructure health, subsurface hydrogeology/EOR process, and industrial/oil spills, and in assisting/improving unconventional depth surveys/exploration. Keywords: Integrated-Methods, Electrical Imaging, Immiscible EOR, Oil Spills, Hydrological/Process monitoringPermalink: https://doi.org/10.4133/SAGEEP.27-146FiguresReferencesRelatedDetails Symposium on the Application of Geophysics to Engineering and Environmental Problems 2014ISSN (online):1554-8015Copyright: 2014 Pages: 559 publication data© 2014 Published in electronic format with permission by the Society of Exploration Geophysicists and Environment and Engineering Geophysical SocietyPublisher:Environmental & Engineering Geophysical Society HistoryPublished Online: 25 Aug 2014 CITATION INFORMATION Bilal Hassan, Stephen Butt, and Charles Hurich, (2014), "RESULTS OF A LABORATORY STUDY HIGHLIGHTING THE POTENTIAL OF INTEGRATED P-WAVE AND ELECTRICAL METHODS APPLICATION IN NEAR-SURFACE," Symposium on the Application of Geophysics to Engineering and Environmental Problems Proceedings : 422-433. https://doi.org/10.4133/SAGEEP.27-146 Plain-Language Summary KeywordsIntegrated-MethodsElectrical ImagingImmiscible EOROil SpillsHydrological/Process monitoringPDF DownloadLoading ...