Full text loading...
-
Q Extraction from Full-waveform Acoustic Logs with Optimized Statistical Averaging Method
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
Estimating intrinsic attenuation from sonic waveforms recorded in boreholes has been recognized for a long time as a source of information that can be used in subsequent rock physics analyses. The statistical averaging (SA) method is currently considered as the most advanced attenuation extraction method. In this paper, we synthesize all the advantages of previous different implementations of SA method and apply this optimized workflow to a real borehole data set from an exploration well called Harvey-1 in Australia. Our workflow includes a proper correction for the elastic amplitude changing effects, and the correction is quantified through an elastic simulation of monopole sonic logging with real axis integration method. We emphasize the point that intrinsic attenuation cannot be accurately obtained with SA method without correction for the elastic amplitude changing effects. The P-wave attenuation extracted with our SA workflow is stable, and the result after correction is more consistent with laboratory measurements. Since P-wave attenuation is sensitive to the presence of gas, our results indicate that sonic attenuation can be used to monitor CO2 migration after injection.