This paper presents findings from a comprehensive assessment aimed at identifying deep geological storage formations suitable for the secure isolation of chemically active gases, including anthropogenic CO₂. Although Kazakhstan currently lacks operational industrial-scale CO₂ storage sites, high annual emissions exceeding 2 million tonnes are concentrated in its southern region, specifically Almaty city and the surrounding Almaty Region. Despite this pressing need, the precise location, availability, and capacity of potential storage sites in this area remain poorly understood. By synthesizing legacy geological, geophysical, and hydrogeological datasets compiled within the eastern Ili Depression, this study evaluates regional deep saline aquifers for potential CO₂ geological storage under favorable techno-economic conditions. It must be clearly emphasized that this study focuses exclusively on deep groundwater aquifers (saline aquifers). Leveraging historical seismic, drilling, and well-logging data originally acquired for petroleum and water resource exploration, we constrain the stratigraphic architecture and structural framework of prospective storage units. The lithostratigraphic framework of the sedimentary cover in the Ili Basin is established, identifying key reservoir intervals and effective sealing formations. The results indicate that the eastern Ili Depression offers highly favorable conditions for geologic storage, with Permian, Triassic, and Jurassic sedimentary successions reaching thicknesses of up to 1200 m. Reservoir intervals are identified across major stratigraphic units, with potential storage formations accounting for up to 60% of the stratigraphic volume. Specifically, the Miocene–Paleogene and Jurassic intervals host sandstone reservoirs exceeding 10 m in thickness, with porosities reaching up to 30%. Upper Jurassic clayey successions function as effective intraformational seals for Middle Jurassic reservoirs, while Upper Cretaceous clay sequences provide regional caprock integrity for the overlying Neogene–Paleogene sandy intervals. These geological settings satisfy rigorous containment criteria required for secure gas sequestration. These insights into the deep architecture of the Ili Depression elucidate key geological controls governing prospective storage sites, paving the way for future carbon capture and storage (CCS) initiatives in one of Kazakhstan’s most vital economic regions.

This paper presents the results of research aimed at identifying deep-seated natural sealed reservoirs for the isolation of chemically active gases, including CO₂. A comprehensive analysis of geological, geophysical, and hydrogeological data was conducted to identify potential structures within the aquifers of Almaty and the Almaty region (Southern Kazakhstan) capable of capturing and storing carbon dioxide under geographically favorable and economically viable conditions. The study utilizes seismic survey results and drilling data from the eastern part of the Ili Basin, demonstrating the efficacy of seismic exploration in identifying stratigraphic horizons and their structural-tectonic settings. Based on an integrated analysis of available geo-physic information, the lithological and stratigraphic characteristics of the sedimentary cover in the Ili Basin are substantiated. Key caprock sequences and reservoir units for potential storage sites are identified, and recommendations for further geological exploration are provided. Five reflecting horizons were identified within the geological section of the troughs. It was established that the Miocene-Paleogene and Jurassic horizons contain sandstone reservoirs with a thickness exceeding 10 m and enhanced filtration properties. Clay complexes are prevalent in the Upper Jurassic deposits, which can serve as a caprock for these reservoir rocks. Furthermore, the Upper Cretaceous clay sequence may act as a fluid seal for the Neogene-Paleogene sandy horizons. Such conditions meet the requirements for sealed reservoirs for the isolation of chemically active gases, including CO₂. According to hydrogeological studies, seven aquifer complexes are distinguished: Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene and Quaternary. The novelty and practical significance of this research lie in obtaining new information on the geological structure of deep horizons in poorly studied areas of the Ili Basin and establishing favorable geological factors for identifying potential sites suitable for carbon dioxide sequestration.

This paper presents the results of research evaluating the potential of the Zharkent Depression in Southern Kazakhstan as a promising geological structure for identifying natural reservoirs within aquifer formations for long-term underground CO₂ storage. Based on seismic and well data integrated with modern geographic information sys-tems (GIS), digital surface models of reflecting horizons correlated with structur-al-stratigraphic complexes were constructed. Structural, lithological, and petrophysical modeling was performed, providing three-dimensional distributions of lithology and porosity, as well as reservoir saturation forecasts. The geological reservoir model was developed using geostatistical analysis principles. The three-dimensional geo-hydrodynamic model is based on numerical methods for estimating reservoir hydrodynamic parameters. The injection dynamics and under-ground gas storage models, including an economic efficiency assessment, were calcu-lated for a long-term period. It was established that the Jurassic aquifers, characterized by thick sandstone sequences with enhanced reservoir properties (porosity and permeability), represent the most favorable environment for carbon dioxide injection and storage. Simulation of the in-jection and storage processes yielded predictive saturation cubes and quantitative characterization of CO₂ volume and distribution within the trap under specified injec-tion conditions. The potential volume of injected gas was calculated, and an optimal CO₂ storage strategy in the aquifer was determined through the year 2126. The findings indicate that the storage reservoirs in the Zharkent Depression possess a CO₂ seques-tration potential comparable to existing global large-scale carbon capture and storage projects.