This paper is devoted to a study of the characteristic features of the composition and structure of crude oils from terrigenous Devonian producing deposits in the Minnibaevskii section of the Romashkino and Pervomai fields. Using the SynOil program, we identified the features of the molecular weight distribution of n-paraffins, cyclohexanes, and monoalkylbenzenes associated with the formation and transformation conditions in the crude oil deposits.