The article presents a geochemical interpretation of data on the physicochemical properties and individual composition of oils and condensates from the Bovanenkovo and East-Bovanenkovo fields (the distribution of light hydrocarbons (HC) C3-C8, n -alkanes, acyclic isoprenanes, steranes, terpanes, arenes). The main purpose of this study is the identification of the main sources of HC fluids, as well as geological and geochemical processes that have affected their composition and the formation of deposits. It is shown that the formation of naphthides from both fields occurred in several stages with the participation of the organic matter (OM) varying in genotype, in particular due to the widespread processes of secondary migration and reformation of primary deposits. Oils and condensates from the Jurassic deposits of the Bovanenkovo field were established to have a genetic relationship with the terrestrial OM of the Lower and Middle Jurassic strata, which was a source of both liquid and gaseous hydrocarbons and subsequently formed these oil and gas accumulations. It is assumed that the naphthides of the Neocomian part of the section are derivatives of the aquatic OM in the Bazhenov formation. These gas-condensate deposits during their formation were differently enriched with light components generated by the terrestrial OM of the Lower and Middle Jurassic strata. The effect of biodegradation processes on the composition of condensates of the Aptian and Albian-Cenomanian deposits was recorded. Their formation is considered having occurred due to the carbonaceous OM of the Cretaceous strata, which served as a source of primary "immature" condensates with terrestrial composition, which were mixed with secondary-migration HC fluids generated by: the aquatic OM of the Bazhenov formation in the case of gas condensates of the Aptian deposits; terrestrial OM of the Lower and Middle Jurassic strata in the case of the pools of the Albian-Cenomanian reservoir. In addition, the naphthides formed with the participation of aquatic OM are observed to be confined to the East-Bovanenkovo field and the southeastern part of the Bovanenkovo field.