CONSTRUCTION OF SEISMIC VELOCITY MODEL USING ELECTROMAGNETIC DATA ON PERMAFROST LAYER
(Kaplan S.A. Sokolova E.Yu. Yakovlev D.V. Klokova V.P. Shpektorov A.L. Slinchuk G.E. )
Permafrost rocks, which cover about 60% of the territory of Russia, differ in their physical properties from thawed counterparts. Seismic velocities and electrical resistivity increase significantly in frozen rock. When building models of the depth distribution of seismic velocities, special consideration is needed for the distortions introduced by high-speed permafrost strata, which are also characterized by lateral heterogeneity (taliks) and variable thickness. Geoelectrical sections constructed along the lines of seismic profiles allow us to determine the variations in thickness of the permafrost layer. In addition, basing on known (regional, literary and well-logging data) and newly established correlation dependences between resistance and seismic velocities, it is possible to determine the initial velocities of the highest, unresolved, horizons for their usage in seismic modeling and inversion. The geophysical data obtained in the Eastern part of the Yenisei-Khatanga regional trough, located in the center of Taimyr peninsula, served as a ground material for elaboration of the methodology of the electrical exploration data on the structure of the permafrost implementation for the seismic exploration section construction. Regional geophysical work is currently being carried out in this area in order to identify oil and gas prospective zones.......