Lithological and stratigraphic correlation of Mesozoic and Cenozoic deposits of the Balkhash sedimentary basin for appraisal of hydrocarbon resources

Background: Development of a geological framework to substantiate and quantitatively evaluate the hydrocarbon potential of the Balkhash sedimentary basin cover. Aim: Identification of the key estimation parameters for potentially promising hydrocarbon plays (area, thickness, lithological composition) on a qualitatively new geological lithological and stratigraphic base for determining the hydrocarbon potential of the Balkhash sedimentary basin. Materials and methods: Correlation of lithological and stratigraphic sequences of Mesozoic (Triassic-Cretaceous) and Cenozoic (Paleogene-Neogene) deposits in accordance with the stratigraphic charts of the Phanerozoic of Kazakhstan based on the International Chronostratigraphic Scale from 2016 to 2021. Results: The paper investigates the geological structure, zoning, and platform cover of the Balkhash sedimentary basin (BB). During the study, two tectonic units were identified within the BB structure: the West Balkhash and East Balkhash (Lepsin) depressions. Lithological and stratigraphic charts of the Balkhash sedimentary basin have been created and refined to serve as a basis for appraising its hydrocarbon resources. Additionally, prospective hydrocarbon plays have been identified, and their thicknesses have been measured. Furthermore, the analysis of lithological and stratigraphic data has allowed for the determination of the thicknesses, distribution areas of these discoveries, and the organic carbon content within them. These parameters are critical for calculating predicted hydrocarbon resources. Data regarding the development areas of promising BB hydrocarbon plays were obtained from the results of constructing lithological and paleogeographic maps and sections. Conclusion: Based on the developed lithological and stratigraphic model, charts of the Balkhash basin have been drawn up allowing for appraisal of the hydrocarbon potential. The oil and gas potential of the region is estimated to be very low due to the characteristics of the sedimentary cover structure, tectonic activity, and types of possible traps. However, we have identified prospective gas plays that exhibit certain capacities, areas, and organic matter content.