Page 475 - Enhanced Oil Recovery in Shale and Tight Reservoirs

Air injection 439

Table 13.8 Reservoir and thermal parameters used in the lab scale
simulation model.
Parameter Value
Reference depth (cm) 0
Porosity (dimensionless) 0.41
Horizontal permeability (mD) 12,700
kv/kh (dimensionless) 1
Oil saturation (dimensionless) 0.882
Reference pressure (kPa) 4100
Original reservoir temperature ( C) 100

Rock volumetric heat capacity (J/(cm $ C)) 2.35
3
Rock thermal conductivity (J/(cm$min$ C)) 1

Water thermal conductivity (J/(cm$min$ C)) 0.36

Oil thermal conductivity (J/(cm$min$ C)) 0.077

Gas thermal conductivity (J/(cm$min$ C)) 0.083

Temperature of injected gas ( C) 100

can history-match TG/DSC experiments with limited experimental time
and heat loss. Using this history-matched model, slow reactions and
adiabatic conditions can be simulated, and the feasibility of spontaneous
ignition may be studied. A laboratory-scale model may be upscaled to a field
model so that spontaneous ignition in field can be studied.
Huang and Sheng (2018) built a 1D laboratory-scale base model of grids
of 36 1 1. The total grid block size was set at 5.08, 9.94, and 9.94 cm in
the x, y, z directions, respectively. Air is injected at block (36 1 1) and the
production end is at block (1 1 1). The main reservoir properties and thermal
properties were taken from Belgrave et al. (1993), presented in Table 13.8.
The kinetic parameters and the reaction scheme which contains three reac-
tions with 11 components are from Huang and Sheng (2017c), as presented
in Table 13.6. In the base laboratory-scale model, the over/underburden
volumetric heat capacity of 2.350 J/(cm $ C) and thermal conductivity of
3
formation adjacent to the reservoir of 1.038 J/(cm$min$ C) are used.

Fig. 13.22 shows the temperature profiles at grids (6 1 1), (18 1 1), and
(35 1 1) in the base case model and the adiabatic case (Huang and Sheng,
2018). The temperature increase from the original reservoir temperature
of 100 C is around 10 C in the base case and around 25 C in the adiabatic

case due to LTO reactions. Such temperature increases are close to those
reported by Jia et al. (2012a) and Abu-Khamsin et al. (2001). Such low
temperature may not lead to spontaneous ignition. Note that in the adiabatic
case, the temperatures near the production end (blocks (18 1 1) and (6 1 1))
maintain at the peak temperatures because of no heat loss, while the