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. The reflection seismic method is extremely important for the hydrocarbon exploration. With more complex geological structures, as the pre-salt from Santos Basin, the reservoir exploration becomes more challenging and the multicomponent seismic investigation improves its mapping and characterization. To obtain multicomponent seismic data of an offshore survey it is necessary to use the OBN (Ocean Bottom Nodes) technology. The converted wave behavior, the large offsets and the difference of datum between source and receptors for layered media, results in strong nonhyperbolic travel-time events. Furthermore, the complexity and peculiarities of some unconventional reservoirs found in the pre-salt also increase the difficulty to perform the velocity analysis. For these reasons, it is necessary to use nonhyperbolic multiparametric travel-time approximations to control the nonhyperbolicity. Here we perform the comparison of nonhyperbolic travel-time approximations of seismic reflection events derived from geological models. The numerical study was considered as an inverse problem and it was treated according to an optimization criterion. The complexity analysis was performed in order to understand the behavior of each approximation concerning the unicity. After the computation of the relative errors between the observed curve and the calculated curve for each nonhyperbolic approximation, it was possible to find out the one with the highest accuracy for the events tested here. Keywords:  multicomponent, OBN, nonhyperbolic. RESUMO. Ometodo sismico de reflexao e extremamente importante para a exploracao de hidrocarbonetos. Comestruturas geologicasmais complexas, como o pre-sal da Bacia de Santos, a exploracao de reservatorios se tornamais desafiadora e a utilizacao da sismica multicomponente promove o mapeamento e caracterizacao estrutural. Para obter-se dados de sismica multicomponente em um levantamento offshore e necessario utilizar a tecnologia OBN ( Ocean Bottom Nodes ). O comportamento de ondas convertidas, longos afastamentos e diferenca de datum entre fonte e receptor pra meios estratificados resultam em uma forte nao-hiperbolicidade dos eventos de tempos de trânsito. Alem disso, a complexidade e peculiaridades, de alguns reservatorios nao convencionais encontrados no pre-sal, tambem aumentam a dificuldade em realizar a analise de velocidades. Por estes motivos, e necessario usar aproximacoes nao-hiperbolicas multiparametricas de tempos de trânsito para controlar os efeitos da nao-hiperbolicidade. No presente trabalho, foi realizada a comparacao de aproximacoes nao-hiperbolicas de tempos de trânsito de eventos sismicos de reflexao provenientes de modelos geologicos. O estudo numerico foi considerado como um problema inverso e foi tratado de acordo com um criterio de otimizacao. A analise de complexidade foi realizada para compreender o comportamento de cada aproximacao com respeito a unicidade. Apos computar os erros relativos entre a curva observada e as calculadas com cada aproximacao, foi possivel descobrir a aproximacao que apresentou maior precisao para os testes realizado. Palavras-chave : multicomponente, OBN, nao-hiperbolicas.

COMPARISON OF TRAVEL-TIME APPROXIMATIONS FOR UNCONVENTIONAL RESERVOIRS FROM SANTOS BASIN, BRAZIL