Patent ID: 7889599

Claim:
Method of determining the velocity v and anellipticity η parameters for processing seismic traces obtained from seismic receivers in a common midpoint (CMP) gather including an anelliptic (Normal Move Out) NMO correction, comprising: a preliminary step to define a plurality of nodes (dtn, τ 0 ) in a CMP gather of a series of seismic traces, at least a portion of said traces corresponding to signals reflected by geological interfaces of a subsurface zone, said nodes being indicative of parameters dtn and τ 0 , wherein dtn represent the NMO correction for the maximum offset and τ 0 represent the zero offset travel time in hyperbolic coordinates, said preliminary step being followed by for each node (dtn, τ 0 ) defined in the preliminary step, the following steps: performing static NMO correction of traces in the CMP gather as a function of the values of the said parameters dtn, τ 0 at the node considered, and calculating the semblance function associated with the said NMO correction for the node considered; and for each picked time t 0 , determining the maximum semblance node (dtn (t 0 ), τ 0 (t 0 )), a step to convert the dtn (t 0 ) and τ 0 (t 0 ) parameters so as to obtain the velocity V (t 0 ) and anellipticity η (t 0 ) laws and a step of processing the seismic traces in view of the obtained velocity V (t 0 ) and anellipticity η (t 0 ) laws, the output of said processing used to represent the seismic traces in one or more images of at least a portion of the geological interfaces of said subsurface zone.