Effects of Contaminated Fluids on Complex Moduli in Porous Rocks; Lab and Field.
Abstract
The interaction between fluids and porous rocks has been measured in the laboratory and in a controlled field experiment. In the laboratory we measured the static and dynamic effect of various contaminated fluids on the wettability, capillary pressure and other flow properties on geometrically simple surfaces. The characteristics of the menisci were quantified by measuring the forces required to deform and move them. Rate dependent surface tension and contact angles describe the hysteresis of the contact line motion. Finally we used geometrically complex surfaces, i.e. real rocks, and observed similar behavior. Then we did a field experiment where we could controllably irrigate a test volume and observe changes in deformation. At low deformation rates, where viscous deformation of the fluid is negligible, the dynamic hystereses of menisci deformation become the dominant mechanism for changes in complex moduli of partially fluid saturated rocks. In the laboratory for contaminated samples we observe attenuation increasing from below 1 Hz to 1 mHz, the limit of our patience in making these measurements. In the field we used microseisms and solid Earth tides as low frequency deformation sources. In the case of the tides we compare changes in observed tilt with theoretical site specific tidal tilts. Preliminary theoretical modeling suggests that indeed small changes in the moduli should be observable in changes in tilt response. In this paper we present our laboratory results and the field data and analysis to date.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.H42B..02S
- Keywords:
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- 1855 Remote sensing (1640);
- 1858 Rocks: chemical properties;
- 1859 Rocks: physical properties;
- 1875 Vadose zone;
- 1895 Instruments and techniques: monitoring