Temperature prediction via reaction heat calculation of burned pseudo-components during in-situ combustion

This work proposes a novel method of temperature prediction during heavy oil in-situ combustion according to the fuel availability (FA) of true boiling point fractions, which is also called pseudo-components. Six kinds of n-alkanes with different carbon number and three crude oil samples from Karamay oil field were used and each oil sample was chosen to get seven true boiling point (TBP) fractions respectively. Kinetic cell experiment with ramped temperature oxidation (RTO) was conducted on each n-alkane and pseudo-component to get the total mole amount of CO and CO2. Combustion tube (CT) experiment was performed to obtain the deviation between the calculated value and measured result, which can be used to validate the accuracy of the new method. The results revealed that the FA of n-alkanes presented linear relationship to the carbon number and the average carbon number for different pseudo-components as well as heavy crude oil could be figured out based on this standard curve. Then the reaction heat for pseudo-components and the whole oil could be calculated and used to predict the temperature of fire front in CT experiment. There is a deviation below 50 °C between the calculation and the thermocouples measurement during the CT experiment, which can be acceptable in reservoir temperature prediction.