Energy & Fuels, Vol.33, No.6, 5538-5543, 2019
Evaluation of Kinetics and Energetics of Thermochemical Fluids for Enhanced Recovery of Heavy Oil and Liquid Condensate
An innovative approach in enhancing oil and gas recovery is the in situ heat generation through exothermic chemical reactions using thermochemical fluids. This study presents the kinetics and energetic analysis of typical thermochemical fluids (NH4Cl and NaNO2) and preliminary evaluation of performance in recovery of heavy oil and gas condensate. As a committed step toward understanding the performance of the fluids, the reactions between the fluids (with and without hydrocarbon fluids-heavy oil or liquid condensate) were monitored in a microreactor under different operating temperatures (T-r approximate to 20, 40, 55, and 75 degrees C) in a close system. The data obtained were used in evaluating the kinetic behavior of the system. Core flooding experiments were also conducted for evaluating the recovery of the gas condensate and heavy oil. Analysis of kinetics and energetics of the system shows that the change in temperature Delta T and the enthalpy change Delta H of the system due to heat generation were approximate to 188 C and approximate to 369 kJ mol(-1), respectively, regardless of the operating temperatures T-r. However, the time to reach peak conversion during the reactions was observed to reduce from 1064 to 382 s as the operating temperature increased from 20 to 75 C. Accordingly, the rate constant K-r (s(-1)) increased from 0.0013 s(-1) under ambient conditions to 0.0156 s(-1) at T-r = 75 degrees C. The reactions were all first order and have been estimated to have the activation energy E-a approximate to 35.5 kJ mol(-1) within the operating temperatures. Moreover, basic applicability of the chemical in condensate recovery (63% at injected PV of 2.1) as well as in the recovery of heavy oil (72% recovery, by injecting 1PV of the chemical) has been confirmed.