Study on heavy oil components transformation path based on core analysis during in-situ combustion process

Coke combustion makes the temperature of heavy oil higher to achieve lower viscosity during in-situ combustion process. The conversion of heavy oil components into coke is significant for the start-up of combustion, but most of the current research results come from laboratory experiments. To further study the conversion of crude oil components in oilfield pilot, this paper divides the reactions of heavy oil into oxidation reaction and thermal reaction, and the reaction mechanism and characteristics are analyzed deeply. Then, the oxidation stages of different sections are determined by analyzing the data of coring wells in the oilfield. Furthermore, the infrared spectra and GC-MS of crude oil in different oxidation stages are analyzed to observe the changes of components and functional groups of heavy oil in this process. Combined core analysis results and the reaction mechanism of heavy oil, the conversional sequence of different components is obtained, and then a systematic heavy oil component conversion path is formed. The above studies validate and improve the conclusions of laboratory experiments and deepen the understanding of the conversion of heavy oil components and the formation of fuel in fire flooding process.