The article considers the results of 2D and 3D basin modeling of the pre-salt depositions in Kazakhstan's part of the Pre-Caspian basin. The initial data on the heat flow and geochemical parameters (total organic carbon content, hydrogen index, thickness and kinetic schemes of kerogen destruction) of the main source rocks are presented.
The performed work represents the influence of the salt diapirs on the temperature distribution in the sediments of the Pre-Caspian basin, expressed in uneven cooling of the pre-salt interval. Main hydrocarbon migration pathways and the large oil and gas accumulation zones were determined according to the results of 2D modeling. The main «kitchen» areas, level of the source rock organic matter catagenesis were determined due to the 3D modeling. As a part of the work, it was estimated which one of the source rocks contributes more to the total hydrocarbon potential of the region. The heterogeneity of the gaseous and liquid fluid saturation of the different flanks of the Pre-Caspian basin was reproduced. According to the work results, Visean-Bashkirian and Upper Devonian reservoirs contain more than 70% of all accumulated hydrocarbons predominantly one the flanks of the Pre-Caspian basin. Also, as part of the work the fluid composition and its variation vertically across the reef buildups were analyzed. In the article the prospects of the clastic intervals of Upper Carboniferous and Lower Permian alluvial fans were evaluated. The particular features of these potential reservoirs are the following: large occurrence depth, undetermined distribution and uncertain petrophysical parameters. The obtained results can be used for determination of the local prospect areas for future more detailed studies.
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