Catalytic effect of clay rocks as natural catalysts on the combustion of heavy oil

Abstract

© 2020 Elsevier B.V. The catalytic effect of clay rocks as matrix for heavy oil combustion in in-situ combustion (ISC) process for enhanced oil recovery was investigated by thermogravimetric analyser coupled with Fourier Transform InfraRed spectroscopy (TG-FTIR) together with kinetic calculation using the Friedman, KAS, and Vyazovkin isoconversional methods. The results reveal that three types of clays show a good catalytic effect verified by a significant reduction in activation energy, mainly manifested as merging fuel deposition (FD) into high-temperature oxidation (HTO) and shifting the temperature peak of the low-temperature oxidation (LTO) and HTO into lower temperature. Mica-type clay shows the best catalytic activity among all the clay rocks. Clinochlore-talc-type clay shows a strong inhibition effect on the isomerization and decomposition reactions (in the later stage of the LTO) as well as the oxidative cracking reactions (in the FD stage), by which a bigger amount of unexpected coke is yielded, which thus significantly reduces combustion efficiency and shifts the HTO into a higher temperature range.