PALEOGEOMORPHOLOGICAL FEATURES OF THE SRIBNENSKA DEPRESSION IN THE LOW CARBON TIME ASSOCIATED WITH OIL AND GAS

Abstract

The work is devoted to the study of geomorphological features of the marine paleobasin and adjacent territories in the Lower Carboniferous time. The object of the study was the Upper Cretaceous terrigenous-domanitic-clay complex deposits of the Dnieper­Donets avalanche. This complex is located within the Sribnenska Depression and its bordering areas. The geological study of this area, borehole data and the results of geophysical survey methods contributed to the possibility of paleogeomorphological modeling of the sedimentary basin. This made it possible to determine the basic criteria and regularities of hydrocarbon trap genesis. Based on the results of well core studies, lithological features of silty-sandy sediments and clayey rocks were established. The Upper Terrigenous-Domanicoid Clayey Complex is predominantly represented by dark-colored flichoidal clayey sediments of the depressive type. Sandstones comprising the terrigenous portion of the complex are characterized by a massive texture and multidirectional layering. Cement in the sandstones is represented by flake monoclinic kaolinite; admixture of degraded hydromica, less frequently calcite, ankerite, and siderite is also observed. Sediments of this type are typical of fluvial outcrops in a depressive, stagnant marine basin. sediments were deposited by submarine delta and turbid currents and contour currents. Paleogeological models reflecting the facies distribution patterns of the paleobasin during the Upper Thaw time have been created on the basis of the logging data. It is shown that structural relations in summer play the role of traps for hydrocarbons. The sedimentation and paleogeomorphological preconditions of oil and gas deposits formation in the terrigenous-domanicoid-clay complex are analyzed on the examples of the known fields and the areas favorable for formation of hydrocarbon deposits are singled out.