The paper presents a generalization and analysis of available geochemical data characterizing gas composition and properties, dispersed Organic Matter, and bitumen from underexplored Cretaceous deposits. The authors conclude that gas occurrences within the Cretaceous series are mainly related to hydrocarbon fluid inflow from the productive Upper Jurassic sequence, which resulted from both vertical and lateral migration along fault zones and through permeable reservoir rocks. Chemical and bitumenological analyses show that higher contents of chloroform-extractable bitumen in Lower Cretaceous rocks, irrespective of Total Organic Carbon (TOC) values, is indicative of the secondary nature of bituminous matter and possible hydrocarbon migration processes. However, the genetic origin of hydrocarbons involved in forming the Cretaceous reservoirs of the Chardzhou flat remains controversial and poorly understood. In particular, it remains unclear whether these accumulations originated from Jurassic hydrocarbons or from an independent Cretaceous source. This uncertainty is primarily because of the limited scope of bituminological, organic geochemical, and other specialized studies in the Cretaceous deposits of the region. A reliable assessment of Jurassic hydrocarbons contribution to the formation of accumulations in the Cretaceous deposits of the Chardzhou flat requires an expansion and deepening of geochemical research program. These studies should include the TOC determination, quantitative and qualitative analysis of chloroform bitumen, Rock-Eval pyrolysis, and a mandatory investigation of the molecular composition of hydrocarbon components in kerogen of dispersed Organic Matter using modern organic geochemistry techniques. Implementing this comprehensive research program will allow clarifying the hydrocarbon genesis, their generation sources and migration pathways, as well as improving the validity of petroleum potential predictions for the Cretaceous deposits of the region.

Nilufar M. Akramova
Candidate of Geological and Mineralogical Sciences,
Head of Laboratory
Institute of Geology and Exploration
of Oil and Gas Deposits,
64, ul. Olimlar, Tashkent, 100164, Uzbekistan
e-mail: nilushhon@mail.ru

Mukhiddin S. Sunnatov  ORCiD
Doctor of Philosophy of Geological and Mineralogical Sciences,
Senior Scientific Researcher,
Deputy Chairman of the Board
JSC “O‘ZLITINEFTGAZ”,
2, ul. Taras Shevchenko, Tashkent, 100029, Uzbekistan
e-mail: muxiddin_99@mail.ru

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