Separation of pp‐ and ps‐wave reflected seismic data using 2d finite offset common‐reflection‐surface traveltime approximation

ABSTRACT Recently, the interest in PS‐converted waves has increased for several applications, such as sub‐basalt layer imaging, impedance estimates and amplitude‐versus‐offset analysis. In this study, we consider the problem of separation of PP‐ and PS‐waves from pre‐stacked multicomponent seismic data in two‐dimensional isotropic medium. We aim to demonstrate that the finite‐offset common‐reflection‐surface traveltime approximation is a good alternative for separating PP‐ and PS‐converted waves in common‐offset and common shot configurations by considering a two‐dimensional isotropic medium. The five parameters of the finite‐offset common‐reflection‐surface are firstly estimated through the inversion methodology called very fast simulated annealing, which estimates all parameters simultaneously. Next, the emergence angle, one of the inverted parameters, is used to build an analytical separation function of PP and PS reflection separation based on the wave polarization equations. Once the PP‐ and PS‐converted waves were separated, the sections are stacked to increase the signal‐to‐noise ratio using the special curves derived from finite‐offset common‐reflection‐surface approximation. We applied this methodology to a synthetic dataset from simple‐layered to complex‐structured media. The numerical results showed that the inverted parameters of the finite offset common‐reflection‐surface and the separation function yield good results for separating PP‐ and PS‐converted waves in noisy common‐offset and common shot gathers.