Research and Application of Coking Behavior of Heavy Oil at High Temperature

Coke is produced through high-temperature thermal conversion of crude oil. The physicochemical properties and production of coke determine the development effect of different thermal recovery technologies for heavy oil. The produced coke will block the pores in electric heating assisted SAGD, while produced coke is the most important fuel in in-situ combustion. Therefore, studying the coking behavior of heavy oil under different thermal recovery technologies, clarifying the coking mechanisms, and effectively controlling the formation of coke are of great significance for efficient exploitation of oil reservoirs. Through synchronous thermal analysis experiments, assisted by high-pressure closed coking experiments and component analysis experiments, the reaction process of heavy oil in the entire temperature range and the formation mechanisms of coke are studied. The determination methods of critical coking temperature are established for electric heating assisted thermal recovery and in-situ combustion. The coking mechanisms of heavy oil can be divided into two types: oxidation deposition coking mechanism and thermal cracking coking mechanism. The critical coking temperature of heavy oil in air atmosphere is about 130℃ lower than that in nitrogen atmosphere. The research can provide theoretical guidance for the design of electric heating temperature in electric heating assisted SAGD and ignition temperature in in-situ combustion.