Geostatistical spectral inversion: The thin layer study using spectral inversion method with geostatistical information

2014 ◽  
Author(s):  
Donghong Zhou* ◽  
Bo Wang ◽  
Zhanghong Shen ◽  
Gang Peng
Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. R57-R67 ◽  
Author(s):  
J. Germán Rubino ◽  
Danilo R. Velis

We studied the seismic attenuation and velocity dispersion effects produced by wave-induced fluid flow in weakly consolidated sandstones containing patchy carbon dioxide [Formula: see text]-brine distributions. The analysis also focuses on the velocity pushdown because of the presence of this gas, as well as on the role of the wave-induced fluid flow (mesoscopic) effects on the amplitude variation with angle (AVA) seismic response of thin layers containing [Formula: see text], such as those found at the Utsira Sand, Sleipner field, offshore Norway. We found that this loss mechanism may play a key role on conventional surface seismic data, suggesting that further data analysis may provide useful information on the characteristics of the fluid distributions in these environments. Numerical experiments let us observe that although mesoscopic effects can be very significant in this kind of media, the seismic response of a given isolated thin layer computed considering such effects is very similar to that of a homogeneous elastic thin layer with a compressional velocity equal to that of the original porous rock averaged in the effective data bandwidth. This suggests that the thin-bed prestack spectral inversion method published by the authors could be used to estimate representative compressional velocities and layer thicknesses in these environments. In effect, results using realistic synthetic prestack seismic data show that isolated [Formula: see text]-bearing thin beds can be characterized in terms of their thicknesses and representative compressional velocities. This information can be qualitatively related to [Formula: see text] saturations and volumes; thus, the prestack spectral inversion method could find application in the monitoring of the evolution of [Formula: see text] plumes at injection sites similar to that at the Sleipner field.


2017 ◽  
Author(s):  
Zhang Qiu* ◽  
Junhua Zhang ◽  
Zhang Xiao Hui ◽  
Hu Wen ◽  
Liu Lei

2014 ◽  
Author(s):  
Qisheng Cai ◽  
Xiangli Bin ◽  
Shusong Du

2013 ◽  
Vol 8 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Selene Quispe ◽  
◽  
Hiroaki Yamanaka ◽  
Zenon Aguilar ◽  
Fernando Lazares ◽  
...  

Effects of local site, propagation path and source in ground motion records observed in Lima, Peru, were separated by the spectral inversion method proposed by Iwata and Irikura (1986 [1], 1988 [2]) to examine the relation between local subsurface conditions and local site amplifications in a frequency range from 0.5 to 20 Hz. S-wave portions of accelerograms in horizontal components observed at 5 stations for 11 events along the Pacific coast of Lima city, Peru, were analyzed. The Q factor was obtained from our inversion results as frequency-dependent functionQS( f )= 80.4f0.63. In terms of local site effects, stations located on alluvial gravel deposits were likely to suffer amplification at frequencies larger than 4 Hz, while one station (CAL site) located on soft soil sediment has different behavior of amplification. We also compared our results with 1-D theoretical computation, observed standard spectral ratio and observed H/V spectra in previous studies, finding that site responses determined by different methods are similar. In addition, we analyzed the relationship between average S-wave velocity in the top 10 meters and the average site amplification factor in a frequency range between 0.5 Hz and 10.0 Hz, showing a good correlation between the two parameters. We also calculated the average transfer function (AvTF) to compare it with the existing amplification map for Lima city, and found that our calculations differed from this map.


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