Broadband laboratory measurements of dispersion in thermally cracked and fluid-saturated soda-lime-silica glass

• Published in: ASEG Extended Abstracts: 24th International Geophysical Conference and Exhibition - Geophysics and Geology Together for Discovery Vol. 2015; no. 1; pp. 1 - 4
• Main Authors: Li, Yang, David, Emmanuel C., Jackson, Ian, Schmitt, Douglas R.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.12.2015
• Subjects: dispersion; poroelasticity; rock physics; seismic properties; soda-lime-silica glass
• ISSN: 2202-0586
• DOI: 10.1071/ASEG2015ab028

To better understand the dispersion of seismic velocities arising from stress-induced fluid flow, broadband laboratory measurements have been conducted on a range of synthetic samples. Forced oscillation methods providing access to low frequencies (mHz - Hz) were combined with measurements at MHz frequencies with ultrasonic methods. Either fully dense soda-lime-silica glass or aggregates of sintered glass beads were subject to broadband tests before and after thermal cracking under dry, argon- and water-saturated conditions in sequence. Crack closure effects under pressure are observed on all samples. A systematic increase in shear modulus, attributed to the suppression of 'squirt' flow, has been monitored on the low-porosity (approximately 2%) cracked glass-bead specimen with both argon and water saturation at ultrasonic frequency. The use of samples with different porosities varying from 0 to 6% promises to distinguish the roles of pores and cracks in fluid-flow-induced dispersion.