Oil and gas bearing potential of crystalline basement in Dnieper-Donets Basin – unbiased view

Abstract

Purpose. Based on the analysis of existing information on the exertions of oil and gas in crystalline rocks of the Dnieper-Donets Basin (DDB), assess the presence of hydrocarbon deposits in certain fields and assess the prospects for the discovery of new ones. Methodology. The study on oil and gas bearing capacity of the crystalline basement was based on the analysis of stock material on oil and gas fields of the Dnieper-Donets Basin, the study on petrographic composition of rocks in sections, analysis of results of well logging, petrophysical studies on rock samples from promising intervals of wells. The peculiarities of the structure of structural-tectonic models of hydrocarbon deposits with oil and gas exertions in the upper parts of the crystalline basement were also taken into account. Findings. A significant number of drilling and well testing results, lithological-petrographic and petrophysical studies were analyzed, which allowed making objective conclusions about the existence of independent oil or gas deposits in the weathering crust of the crystalline basement at already known deposits. The conclusions also concerned the assessment of the industrial (commercial) attractiveness of the discovered deposits or oil and gas exertions in the upper parts of the crystalline basement of the DDB fields. Originality. At the current level of study, it can be argued that within the Eastern Ukrainian oil and gas basin in the Archean-Proterozoic traps apart from the basal horizons of the cover, oil deposits were found in only three fields: Yuliivske, Ulianivske and Hannivske. Undoubtedly, there are hydrocarbon deposits in the Precambrian formations of DDB, but the most extensive discoveries in this direction of exploration and involvement in the development of already discovered accumulations seem to be still ahead. The geological situation should be realistically assessed for the presence of potential areas where the existence of common hydrocarbon deposits in the weathering crust of the foundation and the lower horizons of the sedimentary cover in the DDB is possible. Practical value. The main value of this study is the real assessment of the existence of industrial accumulations of hydrocarbons in already discovered oil and gas fields in DDB. The myth of the presence of many oil and gas deposits in DDB in crystalline rocks of the crystalline basement, which without proper justification has repeatedly been found in the professional literature and in scientific reports at specialized conferences of various levels, has been debunked. Certain prospects for the discovery of oil and gas deposits in the crystalline basement of the Dnieper-Donets Basin are unmarked.