The study presents a seismic and geological characterization of the Meso-Cenozoic sedimentary cover of the Nadym–Pur interfluve area and discusses the morphology of the Jurassic and Aptian–Albian–Cenomanian sedimentary complexes, formation history of structures, and geologic processes responsible for the formation of Cenomanian gas accumulations.

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The Igol’sko-Talovoe oilfield is one of the largest oilfields in southeastern West Siberia, which provides reference for Upper Jurassic reservoirs of the area. The reported studies included integrated interpretation of seismic and well-log data, mapping of tectonic and paleotectonic patterns and sediment thicknesses, as well as seismic-geological and basin modeling. The results were used for tectonic analysis and allowed reconstructing the history of the Igol-Talovoe dome uplift that traps Upper Jurassic oil accumulations. Local uplifts on the Jurassic surface within the Igol-Talovoe dome originated in the Neocomian above basement uplifts produced by erosion and tectonic activity. The local domes merged into a large anticlinal trap as a result of regional-scale vertical crust movements in the Cenozoic. Analysis of the Upper Jurassic hydrocarbon system and basin modeling show that oil generation by the Bazhenov Formaton source rocks began in the Turonian, culminated in the Cenozoic, and continues at present. The process has led to complete filling of the anticlinal trap and formation of the large Igol’sko-Talovoe oilfield. Geological and geophysical data suggest the same scenario for all Upper Jurassic reservoirs in southeastern West Siberia.

The paper deals with the South Kara regional depression covering the southern part of the Kara Sea and presents a comparative analysis of the geologic structure of potential exploration targets in the offshore and onshore regions of the study area. Regional tectonic processes are considered, and the main stages of the formation of large tectonic elements are reconstructed. A comparison of the anticline traps in the onshore parts of the study area and offshore Kara Sea regions is made.

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