THE REGIONAL FEATURES AND SUBSTANTIATION OF A GENERALIZED SEISMIC MODEL OF A CLINOFORM COMPLEX IN THE SHAIM-KRASNOLENINSK REGION AND THE MIDDLE OB AREA

N. M. Belkin

The paper deals with an urgent and poorly studied problem of developing a generalized seismic model of a clinoform complex in the Shaim-Krasnoleninsk and Middle Ob regions which calls for further investigations. As a key proof of this problem solving the author implement a frame network of composite seismic lines, regional and areal seismic survey data. A sequence of reflecting horizons was stratified and traced in the wave field of the Jurassic-Cretaceous interval of the geologic section. The author analyzed peculiar features of the wave pattern. Special attention was paid to the Neocomian-Lower Aptian sedimentary complex in the B and М reflecting horizons interval and its clinoform structure. For the first time the analysis showed a change of submeridional direction of the axial area of the Neocomian-Barremian paleobasin to the sublatitudinal one in the southern portion of the region. West of the axial area of the paleobasin a western boundary is identified at which the Bystrinskaya argillaceous member and НА7 bed as well as НА8 and НА10 sedimentary complexes are adjacent to the Bazhenovskaya Formation top. Inside the B1–B interval closed zones are mapped. They conditionally correspond to sedimentary complexes of the Priobskaya member of clays and НА11–12 beds as well as to the Pimskaya member of clays and НВ1 bed which fill Upper Jurassic paleorelief ruggedness. Such a view will be interesting to specialists in the field of geology and geophysics. A generalized seismic model of Upper Jurassic-Lower Cretaceous sediments was developed on the basis of the carried out studies. It makes possible to specify conditions of sedimentation and distribution of sandy-siltstone-argillaceous material in the Neocomian interval of the section, to forecast presence of oil and gas in the territory under study, and also to outline possibilities for refinement of stratigraphic charts and types of geologic sections.

Key words: reflecting horizon, wave pattern, Neocomian sediments, pinch-out, seismic model.

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