Ignition Delay Time in In-Situ Combustion Formula
Ignition Delay Time in In-Situ Combustion calculates ignition delay for waterflooding and eor workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (M_r, T_a, n_oxy, R, E_a, dh_a, phi, S_o, rho_o, A_c, P_O2) are known and the assumptions behind the cited waterflooding and eor relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, t_ig equals 9,604.862312 s.
35
900
1
1.986
20000
80
0.25
0.6
0.85
0.00001
50
Inputs
M_r
BTU/ft^3-KVolumetric Heat Capacity of Reservoir
T_a
KInitial Absolute Temperature
n_oxy
dimensionlessOxygen Pressure Exponent
R
BTU/lbmol-KGas Constant
E_a
BTU/lbmolActivation Energy
dh_a
BTUHeat Generated by Oxygen
phi
fractionPorosity
S_o
fractionOil Saturation
rho_o
g/ccOil Density
A_c
1/psi-KPre-Exponential Constant
P_O2
psiPartial Pressure of Oxygen
Outputs
t_ig
Ignition Delay
A_c
Pre-Exponential Constant
dh_a
Heat Generated by Oxygen
phi
Porosity
S_o
Oil Saturation
rho_o
Oil Density
P_O2
Partial Pressure of Oxygen
n_oxy
Oxygen Pressure Exponent
Source and review
reviewedThermal Recovery, Prats, M. (1986)
Prats, M. 1986. Thermal Recovery. Society of Petroleum Engineers, New York, Chapter 8, Page 95.
Source