Accurate interval Q-factor estimation from VSP data

Abstract

Inelastic attenuation, quantified by [Formula: see text], the seismic quality factor, has considerable impact on surface seismic reflection data. A new method for interval [Formula: see text]-factor estimation using near-offset VSP data was based on an objective function minimization measuring the difference between cumulative [Formula: see text] estimates and those calculated through interval [Formula: see text]. To calculate interval [Formula: see text], we used all receiver pairs that provided reasonable [Formula: see text] values. To estimate [Formula: see text] between two receiver levels, we used the equation that links amplitudes at different levels and could provide more accurate [Formula: see text] values than the spectral-ratio method. To improve interval [Formula: see text] estimates, which rely on traveltimes, we used a high-accuracy approach in the frequency domain to determine time shifts. Application of this method to real data demonstrated reasonable correspondence between [Formula: see text] estimates and log data.

Estimation of quality factor based on peak frequency-shift method and redatuming operator: Application in real data set

“…Tonn (1991), using different numerical methods (among them spectral modeling and spectral ratio [Bath, 1974]), estimates the quality factor Q from vertical seismic profile (VSP) data. Blias (2012) also modifies the spectral-ratio method of Bath (1974) for Q determination from near-offset VSP data. From an improvement and update of Dasgupta and Clark's (1998) method, Reine et al (2012) develop a robust method for measuring attenuation from prestack surface seismic gathers.…”

Anisotropic frequency-dependent spreading of seismic waves from first-arrival vertical seismic profile data analysis

“…He also gives a notable discussion of the possibility of negative Q (i.e., κ < 0 in equation 5) and an approach to inversion ensuring κ > 0. Recently, Blias (2012) used an amplitude model similar to our equations 3 and 5, in which the constant term (γ) was inverted for implicitly and used to derive weights for more accurate determination of the spectral-ratio Q-factors. Comparisons to the above methods show that measurement of γ is generally required for accurate measurement of Q −1 ∝ κ.…”

Seismic Wave Dispersion Effects and Inverse Q‐Filter Phase Compensation

“…Futterman (1962) and Kjartansson (1979) have proposed the expression of amplitude attenuation and phase velocity dispersion for description of the earth Q-filter. In order to remove the effect of the earth Qfilter, scholars have developed many methods for Q value inversion using VSP data (Hauge, 1981;Stainsby and Worthington, 1985;Badri and Mooney, 1987;Tonn, 1991;Xu C and R Stewart, 2006;Gao and Yang, 2007;Gao et al, 2008;Blias, 2012) or surface seismic data (Yan and Liu, 2009;Wang, 2011;Zhao et al, 2013), and then use it for inverse Q-filter (Hargreaves and Calvert 1991;Wang, 2002Wang, , 2003Wang, , 2006Yao et al, 2003;Liu et al, 2013;Chen et al, 2014) with amplitude and phase compensation. Inverse Q-filter amplitude compensation for seismic resolution enhancement is widely recognized and applied by the industry, and lots of papers have been published to share the good result for actual seismic data; while the effect of inverse Q-filter phase compensation (Bano, 1996) for velocity dispersion correction to actual seismic data is rarely published.…”