Accounting for medium anisotropy in time seismic data processing on the example of one of the areas of Rosneft Oil Company

UDK: 550.834.017
DOI: 10.24887/0028-2448-2023-9-102-106
Key words: azimuthal processing of seismic data, observed data approximation, seismic wave hodograph, non-hyperbolic hodograph, vertical transverse isotropy (VTI), Eta moveout correction, horizontal transverse isotropy (HTI), fast velocity, slow velocity, azimuth of fast velocity, azimuthally varying velocity attributes
Authors: L.A. Ushakov (RN-KrasnoyarskNIPIneft LLC, RF, Krasnoyarsk), D.K. Dmitrachkov(Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the RAS, RF, Novosibirsk), A.A. Meretskiy (RN-KrasnoyarskNIPIneft LLC, RF, Krasnoyarsk), G.V. Ivanov (RN-KrasnoyarskNIPIneft LLC, RF, Krasnoyarsk), M.A. Samarkin (Rosneft Oil Company, RF, Moscow)

In this article is considered an integrated approach to the study of anisotropy (vertical (VTI) and horizontal (HTI) transverse isotropy) of the medium at one of the areas of Rosneft Oil Company. The completed production cycle of the azimuthal processing of seismic data, in which the values of the azimuths of the shot point (SP) – receiver point (RP) pairs in the trace headers were saved, allows performing the azimuthal velocity analysis and further study of the resulting anisotropic (HTI) attributes. Improvement the efficiency of processing and interpretation of seismic data is one of the priority objectives of Rosneft Oil Company, therefore, today seismic exploration involves the use of a high-tech production complex. By the testing and application of advanced technologies during execution of production project, implementation of knowledge-intensive approaches to data processing, and by the uniqueness of the geological conditions during the survey related to the territory of Eastern Siberia, the realization of such a project can be confidently attributed to the promising development trends of the Company. To provide the possibility of an integrated approach to the study of medium currently actively uses wide-azimuth 3D-CDPM seismic surveys. In the case when the azimuthal processing flow is structured in advance and subsequently completely executed, when the values of the azimuths of the SP-RP pairs were stored in the data, and of course, when isotropic velocity characteristics of the medium were defined in detail, it seems possible, using mathematical complication of the parameters of the medium model, to analyze the anisotropic properties. The paper considers the types of anisotropy of the elastic medium, and shows the actual results of the works on accounting for anisotropy, performed as part of a production project at one of territory of Eastern Siberia. Among them: the results of a three-term approximation of velocities to account for VTI-anisotropy, results of pre-stack Kirchhoff time anisotropic migration, results of an elliptic approximation of velocities within the context of account HTI-anisotropy and subsequent computation the azimuthally varying velocity attributes. The article illustrates changes in the wave field after applying the procedures of accounting for anisotropy on the examples of seismograms and line of seismic cube.

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