Print this pageAPPENDIX II: THE HUNT et al (1991) KINETIC MODEL
The Arrhenius equation can be expressed as
| k = A exp | -E | (1) |
| RT |
where k is the reaction rate constant (1/m.y.), A is the pre-exponential or frequency factor (1/m.y.), E is the activation energy (kJ/mol), R is the ideal gas constant, and T is temperature in kelvins (degrees C + 273).
A time-temperature index (TTI) based on the Arrhenius equation is:
| TTIARR = | A(tn+1 - tn) | {[ | RT²n+1 | exp( | -E | )]-[ | RT²n | exp( | -E | )]} *100 | (2) |
| Tn+1 - Tn | E + 2RTn+1 | RTn+1 | E + 2RTn | RTn |
where t[n] and t[n+1] are, respectively, the time (m.y.) and T[n] and T [n+1] are, respectively, the absolute temperature (degrees C + 273) at the start and end of a 10 degree C interval. R, E, and A are the same as in the Arrhenius equation (1) previously described.
| X% =[1 - exp ( | -STTIARR | )] * 100 | (3) |
| 100 |
Despite different values for the kinetic parameters, E and A, for different source rock types (Table 1), the (summation) TTI [ARR] values are related to the same percentage of oil generated (X%) by the expression: