Page 438 - Enhanced Oil Recovery in Shale and Tight Reservoirs

406 Enhanced Oil Recovery in Shale and Tight Reservoirs

• Oxygen-sand ratio
• Apparent fuel consumption
• Compositions of produced fluids
• Peak combustion temperature

13.2.6 Accelerating rate calorimeter (ARC)
Accelerating rate calorimeter (ARC) introduced in petroleum literature in
1991 (Yannimaras and Tiffin, 1995) is the only instrument to determine
kinetics parameters at high pressure. The basic principle of an ARC is to
maintain a sample of oil and rock in an adiabatic condition, during an
exothermic reaction period; the adiabatic condition is achieved by maintain-
ing the temperature of the sample container same as that of the system
outside the container. The ARC is first heated to a desired temperature
and held for some time for thermal equilibrium. Check whether the heating
rate is less than a preset rate (e.g., 0.02 C/min). If it is, the ARC will

proceed to the preselected temperature step (5 C, e.g.,), following a

heat-wait-search (HWS) sequence, until a self-heat rate is greater than the
preset rate. By this time, the ARC is maintained at adiabatic conditions until
the experiment is completed, as shown in Fig. 13.4 (Townsend and Tou,
1980). The experimental data are presented as the log of exothermic
heat rate versus temperature. Kinetic parameters like activation energy,
preexponential factor, and order of reaction can be derived from ARC

Figure 13.4 Heat-wait-search process of an accelerating rate calorimeter (modified
from Townsend and Tou, 1980).