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Characterization of dispersion, attenuation, and anisotropy at the Buena Vista Hills field, California

Geophysics
By: , , , and 
https://doi.org/10.1190/1.1444926

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Abstract

We create a log of intrinsic dispersion and attenuation for the Antelope Shale formation of the Buena Vista Hills field, San Joaquin Valley, California. High dispersion (or low Q) values correlate with thin sand and carbonate beds within the Antelope Shale. These beds are at least ten times as permeable as the host shale formation, so this effect provides a possible avenue for seismic prediction of permeability. The dispersion log is formed through comparison of crosswell seismic velocities (measured at approximately 1 kHz) and sonic log velocities (measured at approximately 10 kHz). In order to provide a proper basis for comparison, the sonic log must first be adjusted for field anisotropy, scaling effects, and resolution of measurement. We estimate a local shale anisotropy of about 20% based on correlations generated from published measurements of other shale fields. We apply resolution enhancement to capture the thin sand and carbonate beds, and windowed Backus averaging to match the measurement scales. A modeling study verifies the technique, and shows that beds of thickness greater than 30 cm have a measurable signature. The actual resolution is on the order of the crosswell Fresnel length, or about 7 m for the model study.

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Publication type Article
Publication Subtype Journal Article
Title Characterization of dispersion, attenuation, and anisotropy at the Buena Vista Hills field, California
Series title Geophysics
DOI 10.1190/1.1444926
Volume 66
Issue 1
Year Published 2001
Language English
Publisher Society of Exploration Geophysicists
Description 7 p.
First page 90
Last page 96
Country United States
State California
Other Geospatial Buena Vista Hills field, San Joaquin Valley
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