Comparison of nonhyperbolic travel-time equations of multicomponent seismic data using different optimization algorithms

Multicomponent seismic data processing is a challenge concerning the velocity analysis for offshore surveys, and the difficulty increases when OBN (Ocean Bottom Nodes) technology is used. The ray tracing asymmetry caused by wave conversion from P-wave (compressional wave) to S-wave (shearing wave), and the difference of depth between source and receiver generate a nonhyperbolicity in the travel-times of a reflection event of a seismic wave. Large offsets between source and receivers and the complexity of pre-salt structures from Santos Basin also contribute to the event being strongly nonhyperbolic. Aiming to solve this problem, three nonhyperbolic multiparametric equations are used to characterize this behaviour. Since the equations have many variables, the study was treated as an inverse problem according an optimization criterion. Three optimization algorithms were used to accomplish the curve fitting. To understand the behaviour of each equation, the complexity analysis of the objective function topography using L1-norm and L2-norm was performed. Hence, it was possible to determine which combination of equation and optimization algorithm showed the best results and the lower processing time for the studied structure.