Extensional wave attenuation and velocity in partially-saturated sand in the sonic frequency range
Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1 - 9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presence of the gas (QE dropped from 300 for the dry sand to 30 for the partially-saturated sand), with larger attenuation at a given saturation resulting from heterogeneous gas distributions. The extensional wave velocities are in agreement with Gassmann theory for the test with near-homogeneous gas saturation and with a patchy saturation model for the test with heterogeneous gas saturation. These results show that partially-saturated sands under moderate confining pressure can produce strong intrinsic attenuation for extensional waves.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Energy Research. Office of Basic Energy Sciences, Assistant Secretary of Fossil Energy. National Petroleum Office (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 831097
- Report Number(s):
- LBNL-50831; R&D Project: 468106; TRN: US200429%%1468
- Resource Relation:
- Conference: 38th American Rock Mechanics Symposium, Washington DC (US), 07/08/2002--07/10/2002; Other Information: PBD: 17 Jun 2002
- Country of Publication:
- United States
- Language:
- English
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