The University of Southampton
University of Southampton Institutional Repository

Observations of fluid-dependent shear-wave splitting in synthetic porous rocks with aligned penny-shaped fractures

Tillotson, Philip, Chapman, Mark, Best, Angus Ian, Sothcott, Jeremy, McCann, Clive, Shangxu, Wang and Li, Xiang-Yang (2011) Observations of fluid-dependent shear-wave splitting in synthetic porous rocks with aligned penny-shaped fractures Geophysical Prospecting, 59, (1), pp. 111-119. (doi:10.1111/j.1365-2478.2010.00903.x).

Record type: Article

Abstract

P- and S-wave velocity and attenuation coefficients (accurate to ±0.3% and ±0.2 dB/cm, respectively) were measured in synthetic porous rocks with aligned, penny-shaped fractures using the laboratory ultrasonic pulse-echo method. Shearwave splitting was observed by rotating the S-wave transducer and noting the maximum and minimum velocities relative to the fracture direction. A block of synthetic porous rock of fracture density 0.0201 ± 0.0068 and fracture size 3.6 ± 0.38 mm (measured from image analysis of X-ray CT scans) was sub-sampled into three 20–30 mm long, 50 mm diameter core plugs oriented at 0?, 45? and 90? to the fracture normal (transversely isotropic symmetry axis). Full waveform data were collected over the frequency range 500–1000 kHz for both water and glycerin saturated cores to observe the effect of pore fluid viscosity at 1 cP and 100 cP, respectively. The shear-wave splitting observed in the 90? core was 2.15 ± 0.02% for water saturated and 2.39 ± 0.02% for glycerin saturated, in agreement with the theory that suggests that the percentage splitting should be 100 times the fracture density and independent of the saturating fluid. In the 45? core, by contrast, splitting was 0.00 ± 0.02% for water saturation and ?0.77 ± 0.02% for glycerin saturation. This dependence on fracture orientation and pore fluid viscosity is consistent with the poro-visco-elastic theory for aligned, meso-scale fractures in porous rocks. The results suggest the possible use of shear- or converted-wave data to discriminate between fluids on the basis of viscosity variations.

Full text not available from this repository.

More information

Published date: 2011
Organisations: Marine Geoscience

Identifiers

Local EPrints ID: 170217
URI: http://eprints.soton.ac.uk/id/eprint/170217
ISSN: 0016-8025
PURE UUID: 66d76039-0a87-43bc-a5ee-66a68daa7988

Catalogue record

Date deposited: 04 Jan 2011 14:16
Last modified: 18 Jul 2017 12:18

Export record

Altmetrics

Contributors

Author: Philip Tillotson
Author: Mark Chapman
Author: Angus Ian Best
Author: Jeremy Sothcott
Author: Clive McCann
Author: Wang Shangxu
Author: Xiang-Yang Li

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×