Wave-equation time migration

Step 1. Time migration velocity analysis

Automatic velocity analysis in the process of time migration can be accomplished either by scanning a set of different velocities (Yilmaz et al., 2001) or by wave extrapolation in the image-velocity space (Fomel, 2003). It is also possible to estimate time-migration velocity after stack or from limited-offset data by separating and imaging seismic diffractions (Burnett and Fomel, 2011; Dell and Gajewski, 2011; Coimbra et al., 2013; Decker et al., 2017; Harlan et al., 1984; Fomel et al., 2007). Alternatively, time-migration velocity can be estimated directly from prestack data as a data attribute controlled by local slopes of reflection events (Fomel, 2007b; Cooke et al., 2009). Other work on time-migration velocity analysis includes Gelius and Tygel (2015); Santos et al. (2015); Glöckner et al. (2016).