Patent ID: 8139441

Claim:
A method of determining 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, the method comprising: defining a plurality of nodes (dtn, τ 0 ) in the 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 represents the NMO correction for the maximum offset and τ 0 represents a zero offset travel time in hyperbolic coordinates; at a node (dtn, τ 0 ), performing static NMO correction of traces in the CMP gather as a function of the values of said parameters dtn, τ 0 at the node considered; calculating a semblance function associated with said NMO correction for the node considered; for each picked time t 0 , determining a node (dtn (t 0 ), τ 0 (t 0 )) having a maximum semblance; converting the dtn (t 0 ) and τ 0 (t 0 ) parameters of the node having the maximum semblance so as to obtain velocity V (t 0 ) and anellipticity η(t 0 ) laws; and processing, on a processor, 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.