Thermal history modelling
Thermal history modelling is an exercise undertaken during basin modelling to evaluate the temperature history of stratigraphic layers in a sedimentary basin.
The thermal history of a basin is usually calibrated using thermal indicator data, including vitrinite reflectance and fission tracks in the minerals apatite and zircon.
The temperatures undergone by rocks in a sedimentary basin are crucial when attempting to evaluate the quantity, nature and volume of hydrocarbons produced by diagenesis of kerogens.
Fourier's law provides a simplified one-dimensional description of the variation in heat flow Q as a function of thermal conductivity k and thermal gradient dT/''dz:
If the assumptions used to justify this simplified approximation are accepted, we define the simple 1-dimensional heat diffusion equation where temperature T'' at a depth z and time t is given by the equation:
where Tt0 is the surface temperature history, Qt is the heat flow history and k is thermal conductivity. The integral thus represents the integrated thermal conductivity history of a 1-dimensional column of rock.
Thermal history modelling attempts to describe the temperature history Tz,t and therefore requires a knowledge of the burial history of the stratigraphic layers which is obtained through the process of back-stripping.