WHY AFTA® ?
Since the timing of maximum paleotemperatures within
sequences containing prospective hydrocarbon source rocks generally
coincides with maximum hydrocarbon generation, good control on the timing
is a critical factor in assessing regional hydrocarbon prospectivity.
Areas where the main phase of hydrocarbon generation occurred after
structures were formed will clearly be more prospective than areas where
structures post-date hydrocarbon generation.
AFTA thermal history reconstructions provide direct
determination of the timing (as well as the magnitude) of maximum paleotemperatures.
When combined with conventional maturity indicators, particularly vitrinite
reflectance (VR), this approach allows identification and characterisation
of the major episodes of heating and cooling which have affected a sedimentary
sequence. Specifically, the Geotrack methodology of Thermal History
Reconstruction provides the following information:
- magnitude of maximum paleotemperatures in individual samples
- timing of cooling from maximum paleotemperatures
- the style of cooling from maximum paleotemperatures (fast; slow)
- characterisation of mechanisms of heating and cooling
- measurement of paleogeothermal gradients and determination of paleo-heat
- determination of section removed by uplift and erosion (where appropriate)
- reconstructed thermal and burial/uplift histories based on these
Using this information the thermal history of likely
hydrocarbon source rocks can be reconstructed with confidence, on the
basis of measured parameters, rather than relying on modelled results
which often have little rigorous basis. The resulting improvements in
assessment of hydrocarbon prospectivity is clearly beneficial in reducing
The technical basis of Apatite Fission
Track Analysis - details.