Prospects of unconventional oil and gas potential of the Southern zone of Dnieper-Donetsk Depression

Based on the analysis of numerous works and publications, the studying of core samples, the interpretation of well-logging data, the studying of geochemical features and the degree of thermal processing of oil and gas strata, the prospects for unconventional oil and gas potential of geological structures and formations of the Zachepiliv-Liventsivsk shaft of the southern zone of the Dnieper-Donetsk Depression (DDD) are determined, which corresponds to the Rudenkivsko-Proletarsky oil and gas region. Based on the studies, it is proved that the thermal maturity of the rocks of the southern zone within the Zachepiliv-Liventsivsk shaft is extremely uneven both in area and in section and only in certain areas (Bagatoyska-25, Kernosivska-2 wells), or at depths greater than 1500 m (well Zachepilsvska-100) or even 2700 m (well Ulyanivska-18), reaches favorable values sufficient for gas generation. Therefore, despite the rather high content of TOC, which, as a rule, significantly exceeds 1–2 %, the prospects of this section of the southern zone of the DDD with respect to the discovery of shale gas or gas of tight rocks are very problematic. According to the set of indicators characterizing potentially gas-containing shale rocks, the most promising section of this part of the southern zone is the well area. Bagatoyska-25 and Kernosivska-2. Predicted shale gas resources of this section can be preliminary estimated at 40–50 billion m3. This should be taken into account when planning further exploration for shale gas. From the data analysis, one can distinguish depth intervals at which rocks enriched with organic matter can generate oil – from 900 to 3100 m, fatty gas with condensate – from 2100 to 4000 m and dry gas – from 2300 to deeper than 4000 m.