APATITE FISSION TRACK ANALYSIS
and Thermal History Reconstruction
methods of Thermal History Reconstruction using AFTA and VR allow you
significant paleo-thermal episodes - i.e. heating episodes in the past
in which rocks reached paleo-temperatures which were higher than their
the effects of these paleo-thermal episodes. - what were the maximum
paleo-temperatures in individual samples and when did cooling occur?
the episodes - by defining the way paleotemperatures vary with depth,
we can assess the mechanisms of heating and cooling in each episode.
maturation and burial/uplift histories within a consistent framework,
constrained by measured data, allowing rigorous evaluation of likely
hydrocarbon generation scenarios - Constrained
Thermal history in hydrocarbon exploration
Maturity development and hydrocarbon generation
are kinetic processes, controlled by temperature and time. Detailed
understanding of the thermal history of potential source rocks is therefore
crucial in understanding hydrocarbon prospectivity.
Timing of oil generation - a vital component of the
In any prospect evaluation or exploration program,
it is vital to establish not only the presence of mature source rocks
but also to determine when maximum maturity levels were reached and
when hydrocarbon generation took place. Structures will only be prospective
if they were in place when hydrocarbons were generated. Where traps
formed after the hydrocarbon charge, prospects will be dry.
Fission Track Analysis (AFTA®)
situations, the time at which source rocks reached maximum maturity
levels cannot be reconstructed from conventional information. From analysis
of radiation-damage features in detrital apatite grains, AFTA®
provides direct determination of the timing of paleo-thermal episode,
as well as the paleotemperatures reached by individual samples. It can
therefore be used to determine the timing of hydrocarbon charge with
respect to structure formation, and to estimate source rock maturity.
is unique in this ability to produce direct timing information
importance of measured thermal history parameters
histories of potential source rock horizons within prospective sedimentary
basins are controlled chiefly by depth of burial, basal heat flow and
lateral influx of heat due to fluid movements. Changes in these parameters
through time can exert critical controls on the history of hydrocarbon
generation, but can only be detected by application of analytical techniques
which measure their effects. Without such data, serious errors can occur
in assessment of regional hydrocarbon prospectivity.
quantifying and characterising the important episodes of heating and
cooling which have affected a source rock sequence, the explorationist
can proceed to evaluate likely hydrocarbon generation scenarios within
a firm framework, constrained by measured data. Many hours of modelling
using non-viable options can be eliminated, allowing work to be quickly
and efficiently focussed on more realistic, data-constrained solutions.
A user's perspective
... "Why I use THR"
An example of the application
of THR: Anglesea-1
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