US 2006/0133208 A1Published application

Method of determining specular information after prestack seismic imaging

AssigneeInstitut Francais du Petrole

InventorsKarine Broto, Laurence Nicoletis, Hery Rakotoarisoa

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Abstract

A method of determining the specular source/receiver pairs associated with seismic images produced from a transformation of multi-offset seismic wave records as a function of time in the depth domain is disclosed which as subsoil seismic imaging applications. When using a prestack depth migration algorithm of Kirchhoff type, one also calculates and saves, in addition to the necessary traveltimes of the rays from the sources and receivers of the acquisition device to the image points of the image to be migrated, the line parameters of these rays and the desired quantities to be reached in fine. Then, once the prestack migrated volume produced, the local slopes of seismic events of interest for the image points considered are extracted. Comparison between line parameters saved during migration and the normal to the local slopes at the image points considered shows which ray is specular among those for which information has been saved, and allows to produce then the required quantity, which is then referred to as specular quantity.

Claims27

Dependent claims

1) A method for determining a specular source/receiver pairs associated with image points obtained from images of an underground formation resulting from multi-offset records, as a function of time, of seismic waves emitted and picked up by an acquisition device comprising seismic sources and seismic receivers coupled at the surface with the underground formation, the seismic waves being reflected by geologic interfaces of the formation, the method comprising:

a) defining a selection of image points of the images of the formation comprising at least one image point and adjacent points;
b) carrying out a prestack depth migration for the selection of image points wherein data relative to the sources and receivers of the acquisition device, line parameters of rays defined between any source/image point pair and the line parameters of rays defined between any receiver/image point pair are determined and stored;
and, for at least one image point of the selection:
c) determining, for the at least one image point, a local slope of at least one seismic event corresponding to reflections impacting one of the geologic interfaces of the formation;
and
d) determining specular source/receiver pairs associated with the image point, by comparing the local slope associated with the image point with line parameters associated with the image point.

3 more elements

Dependencies are inferred from the claim text.