Method intended to obtain reflection travel times from an interpretation of migrated cylindrical wave seismic data

A method for determining reflection travel times of seismic events picked on 3D records of seismic data corresponding to signals picked up by seismic receivers distributed along acquisition lines in response to an emission in a subsoil of waves from at least one source point, the data having been previously converted to a superposition of migrated cylindrical wave data and interpreted, comprising:

• a) defining a slowness vector ({right arrow over (p)}) whose component (px) in a direction parallel to the acquisition lines defines a slope of the cylindrical waves associated with the various acquisition lines;
• b) for a given seismic receiver situated at an abscissa (XR) on an acquisition line, seeking an abscissa (ξ) of at least one source point on the acquisition line such that a ray starting from the seismic receiver and reflecting on a picked event emerges at said at least one source point, with the slowness vector ({right arrow over (p)}) whose component in the direction of the acquisition line is (−px);
• c) determining a travel time (te(XR)) for the said at least one source point by adding to a value of travel time along said ray a time equal to a product of the slope of the cylindrical wave by an abscissa of the said at least one source point;
• d) repeating steps b) and c) for all the positions of the receivers for which a demigration result is wanted;
• and
• e) repeating steps a) to d) for all the acquisition lines for which a demigration result is wanted;
• and
• f) repeating steps a) to e) for all the values taken by parameter (Px) for which an event has been picked in the corresponding migrated data.