Turonian gas-bearing sediments (Kuznetsov suite) of Kharampurskoye oil field were formed in the environment of continuous post-Senomanian West Siberia transgression and can feature complicated chemogenic-terrigenous type of sedimentation. Considerable distance between the coast (around 300-400 km) and sediment sources allows predicting relatively deepwater sedimentation settings (around 150-200 m) below the storm wave base and predominantly pelitic sediment composition. However, the actual data of core (around 50 m) from the upper part of Kuznetsov suite (silty-clay composition, relics of wave structures and traces of rather intensive bioturbation of sediments) give evidence of shallow depths of sedimentation in the area of Kharampurskoye oil field. With great probability degree the depth of storm influence in flat epicontinental seas can be evaluated as 20-30 m. The results of topography paleoreconstruction and the analysis of regional tectonic trend also indicate the existence of the Kharampur arch during the Turonian period, with 150-180 m height relative to adjoining areas of the sea bottom. The amount of clastic material (fine silt) rhythmically thickens up the section. Swelling and non-swelling components of clays decrease. Layered carbonatization occurs in places. That all allows suggesting a local sea regression, increased eolian processes of clastic material transportation, and episodic invasion of fresh waters (cases of layered carbonatization) at the end of the Kuznetsov suite sedimentation process in Kharampurskoye oil field.
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