Conturites Are a New Object for Searching for Non-Structural Hydrocarbon Traps in the Lower Cretaceous Sediments of Western Siberia

Based on the results of 3D seismic exploration in the section of the Lower Cretaceous clinoform complex of Western Siberia, elongated bedform (sedimentary waves, ripples, ridge, conturite drifts) oriented along the underwater slope perpendicular to the direction of turbidite channels and lobes have been established. On spectral decomposition and amplitude maps, they resemble Aeolian relief shapes, the ridges can be either straight or sinuous with bifurcation. In seismic sections, conturites are diagnosed by the rugged and discontinuous shape of the recording with a variable amplitude of reflections or represent a “traveling wave”. It was found that in the Lower Cretaceous relatively deep-sea marine basin, high-intensity contour currents were constant, acting with different intensity (flow velocity) in different parts of the marine basin. They eroded and redeposited sedimentary sediments of turbidite genesis, thereby affecting the final morphology of the deep-sea fans of outflow. Under the influence of bottom currents, both mixed tidalite-conturite-turbidite systems and individual conturite drifts of various lithological composition were formed. The processing of sediments by bottom currents is indicated by characteristic sedimentary structures: double layers, bidirectional and unidirectional crossbedding, horizontal lamination, flaser and lenticular bedding, climbing-ripples cross-bedding, normal and reverse grading, as well as in places the intensive development of bioturbation processing of sediments, which are not typical for turbidite deposits. Sandy conturite drifts can serve as new objects for the extraction of non-structural hydrocarbon traps in the deep-sea marine basin of the West Siberian megabasin.