|Alaska North Slope:
Constraining the Timing,
Magnitude and Distribution
of Multiple Thermal Events
Geotrack International Pty Ltd (Melbourne, Australia),
Micropaleo Consultants, Inc. (Encinitas, California)
timing and intensity of geological events across the North Slope of
Alaska is of fundamental importance to finding oil and gas in the region.
One way to constrain these events is to measure the thermal history
of rock units. Such constraints provide the necessary framework with
which the structural evolution and prospectivity of the region can be
practically assessed for exploration. Without firm constraints on timing
and magnitude of paleo-thermal events, the exercise of describing and
ranking prospective petroleum plays becomes strongly dependent on assumptions,
which may be wildly inaccurate. By basing assessment on measured data,
costs and risks of exploration can be significantly decreased.
Central to the
concept of the Petroleum System is knowing the Relative and Absolute
Timing of events. Those regions where the main phase of hydrocarbon
generation took place after structures were formed are likely to be
most prospective at the present day. The main objective of this study
is to provide direct (measured) constraints on the thermal history in
the region, which can be used to reconstruct the history of hydrocarbon
generation and structural development across the region. This provides
a coherent framework for defining the most prospective areas.
track analysis (AFTA®), combined with VR (vitrinite reflectance)
data, has been used to directly measure the timing, intensity and regional
variation of multiple paleo-thermal events across northern Alaska in
this study. AFTA provides direct measurement of the timing and magnitude
of the paleo-thermal episodes responsible for maturity development and
hydrocarbon generation, while VR data also provide control on the maximum
paleotemperature. The paleotemperature estimates derived from AFTA and
VR also provide quantitative constraints on paleogeothermal gradients,
paleo-heat flow and amounts of section removed during exhumation. Knowing
these variables through direct measurement necessarily reduces exploration
risk, particularly by removing the guesswork associated with determining
the time at which source rocks cooled from their maximum paleotemperatures,
and how this varies across the region. Since this effectively datest
he time at which hydrocarbon generation effectively ceases, knowledge
of this key aspect of the petroleum system can result in significant
reduction in exploration risk.
Scope of study
AFTA data from
approximately 60 outcrop samples will be included in the study.
Of these AFTA outcrop samples, ~10 will be newly collected and analyzed,
~20 will be re-processed and ~30 others from published results will
be included and reviewed in the context of the new results. This sampling
program and data review ensure good regional coverage, and full and
consistent assessment of all relevant publicly available data.
the new outcrop samples will be combined with results from well
samples (AFTA and VR) from about 11 wells. Some of the re-processed
AFTA analyses will include data released to Geotrack by previous Geotrack
clients and companies participating in the study. Thus in summary, the
study will consist of approximately 110 AFTA samples and 100 VR samples
The final report
- A comprehensive tabulation
and presentation of all analytical data derived for AFTA - i.e.,
measured grain ages, lengths and chlorine content - and for VR
- i.e., mean reflectances, histograms, and detailed maceral descriptions
for any new analyses.
- Thermal history interpretations
and justifications for all new and re-processed AFTA data.
- Maximum paleotemperature
determinations from all new and reliable VR data, together with
an assessement of WHEN these maturities developed, in light of
the AFTA results.
- A comprehensive review
of all available and existing VR data from the region that can
accessed for this study. Contributions of maturity data from participating
companies are invited.
- Discussion and estimates
of the cause of heating, eroded section, paleogeothermal gradient
and maturity history for each of the wells selected for THR.
- Answers, where possible,
to the questions posed in Section 4 of this proposal, and discussion
of the results in terms of the implications for various petroleum
systems in the region (e.g. reservoir quality of the Brookian
- A discussion of overall
results in terms of consequences for future exploration programs.
The report is now available. Contact
us for details of prices. A detailed proposal is available on request,
containing further details on well names, sample locations, the investigators
and their experience in the region. Group escalations are available.
For further information
|Geotrack International Pty
Dr Paul Green
37 Melville Rd
Brunswick West, VIC 3055
|Micropaleo Consultants Inc
Dr. Michael Mickey
Dr. Allan Byrnes (Geocore)
329 Chapalita Dr.
Encinitas, CA 92024