Contact line friction and surface tension effects on seismic attenuation and effective bulk moduli in rock with a partially saturated crack
| Autor: | Andreas Bauer, Alexander Y. Rozhko |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010504 meteorology & atmospheric sciences
Capillary action Attenuation Mechanics 010502 geochemistry & geophysics 01 natural sciences Seismic wave Physics::Geophysics Stress (mechanics) Contact angle Surface tension Hysteresis Geophysics Geochemistry and Petrology Wetting 0105 earth and related environmental sciences |
| Zdroj: | Geophysical Prospecting. 67:913-934 |
| ISSN: | 1365-2478 0016-8025 |
| DOI: | 10.1111/1365-2478.12653 |
| Popis: | The effect of surface phenomena occurring at the interfaces between immiscible fluids and a solid on the seismic attributes of partially saturated rocks has not yet been fully studied. Meanwhile, over the past two decades considerable progress has been made in the physics of wetting to understand effects such as contact line friction, contact line pinning, contact angle hysteresis, and equilibrium contact angle. In this paper, we developed a new rock physics model considering the aforementioned effects on seismic properties of the rock with a partially saturated plane-strain crack. We demonstrated that for small wave-induced stress perturbations, the contact line of the interface meniscus will remain pinned, while the meniscus will bulge and change its shape through the change of the contact angles. When the stress perturbation is larger than a critical value, the contact line will move with advancing or receding contact angle depending on the direction of contact line motion. A critical stress perturbation predicted by our model can be in the range of 102−104 Pa, that is typical for linear seismic waves. Our model predicts strong seismic attenuation in the case when the contact line is moving. When the contact line is pinned, the attenuation is negligibly small. Seismic attenuation is associated with the hysteresis of loading and unloading bulk moduli, predicted by our model. The hysteresis is large when the contact line is moving and negligibly small when the contact line is pinned. Furthermore, we demonstrate that the bulk modulus of the rock with a partially saturated crack depends also on the surface tension and on the contact angle hysteresis. These parameters are typically neglected during calculation of the effecting fluid moduli by applying different averaging techniques. We demonstrate that contact line friction may be a dominant seismic attenuation mechanism in the low frequency limit ( |
| Databáze: | OpenAIRE |
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