3D prestack depth migration with compensation for frequency dependent absorption and dispersion

Abstract

Spatial variations in the transmission properties of the overburden cause seismic amplitude attenuation, wavelet phase distortion and seismic resolution reduction on deeper horizons. This poses problems for the seismic interpretation, tying of migration images with well-log data and AVO analysis. We developed a prestack depth Q migration approach to compensate for the frequency dependent dissipation effects in the migration process. A 3D tomographic amplitude inversion approach may be used for the estimation of absorption model. Examples show that the method can mitigate these frequency dependent dissipation effects caused by transmission anomalies and should be considered as one of the processes for amplitude preserving processing that is important for AVO analysis when transmission anomalies are present.

Attenuation compensation in multicomponent Gaussian beam prestack depth migration

“…According to Xie et al (2009), wave propagation in a viscoelastic medium can be treated as wave propagation in an elastic medium with complex velocity. The complex velocity is given in terms of the (real) elastic velocities V P and V S , where Q P and Q S are the quality factors for the P and S waves, respectively.…”

“…For Kirchhoff Q migration, Traynin et al (2008) used the Kirchhoff prestack depth Q migration method to perform amplitude and bandwidth recovery beneath gas zones. Xie et al (2009) developed a prestack Kirchhoff Q migration method that calculated the absorption effects along rays using ray tracing and compensated for each frequency band in the migration. For the Q waveequation migration method, Zhang et al (2010) derived a viscoacoustic wave equation in the time domain and proposed the Q reverse-time migration (RTM) method to compensate for the energy absorption in prestack time migration.…”

Wave-equation Q tomography

“…For example, Xin et al (2008) and Xie et al (2009) compensate for the attenuation loss by ray-tracing methods. For 3D Kirchhoff migration, Traynin et al (2008) replace the conventional acoustic traveltime expression with a frequency-dependent complex traveltime expression containing three terms.…”

Skeletonized wave-equation inversion for Q

“…For example, Xin et al (2008) and Xie et al (2009) compensated for the attenuation loss by ray-tracing methods. Dai and West (1994), Yu et al (2002), Wang (2008) and Valenciano et al (2011) used one-way wave-equation migration in the frequency domain for attenuation compensation.…”