Effect of pressure on the isoconversional in situ combustion kinetic analysis of Bati Raman crude oil

Knowledge of the chemical kinetics of an oil is critical for the success of an in situ combustion (ISC) project. Chemical kinetics studies help to formulate reaction schemes which help to understand the various reactions and conditions that favor the propagation and sustainability of combustion front in crude oil oxidation. The objective of this study is to investigate the effect of pressure on the kinetic analysis of in situ combustion and to understand the kinetics of Bati Raman crude oil, a 12° API crude from the Southeastern part of Turkey. In this study, ramped temperature oxidation (RTO) experiments with effluent gas analysis (EGA) are conducted at various pressures of 690, 1034, 1380, and 1724 kPag on Bati Raman crude oil. The experiments are conducted with clean non-reactive sandstone; crushed and sieved at a certain size. The isoconversional method generates an isoconversional fingerprint which shows changing reaction mechanisms on a plot of activation energy versus conversion or average temperature. Activation energies are evaluated from the fingerprints generated at the various pressures. In addition, reaction schemes are formulated for each operating pressure with associated stoichiometric coefficients and activation energy values. The results indicate that estimated activation energy values in the HTO region are increasing with increasing pressure. On the other hand, there is not a clear trend in low temperature oxidation (LTO) region. LTO activation energy values stay fairly constant with increasing pressure. Reaction schemes were proposed for Bati Raman crude oil at different operating pressures using the various regions of reaction mechanisms deconvolved on the generated isoconversional fingerprints. There is a close proximity of the stoichiometry of the reactions at different pressures which may be indicative of a good trend of consistency in the reaction schemes. Importantly, this work illustrates the effect of pressure on the isoconversional kinetic analysis of Bati Raman crude oil as well as kinetic schemes, generated based on the experiments, to be used in simulation studies.