Exploration Insights September 2020 | Page 9

Exploration Insights | 9
Petroleum System Index
Number of reservoirs
Simpson
Bone Springs
0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85
way, higher risk petroleum systems can be easily
identified, and a preliminary understanding of
their limitations can be revealed.
Intra-Basinal Variability
© 2020 Halliburton
Petroleum System Index
Cisuralian
Mississippian
Late Devonian
Late Ordovician
Exceptional
>50,000 MMBOE
Figure 5> A cross plot of the holistic petroleum system
index score and the number of reservoirs charged by studied
petroleum systems in the Permian Basin.
The schema can easily identify variability within
the petroleum systems of a given basin.
Early Permian, Early Carboniferous, Late
Devonian, and Ordovician petroleum systems
occur in the Permian Basin (Figure 2).
Collectively, these systems result in one of the
most prolific oil producing regions on Earth. It
is no surprise that three of these petroleum
systems (the Early Permian Wolfcamp, the Late
Devonian Woodford, and the Early Carboniferous
Barnett) have excellent qualities. They also have
excellent holistic petroleum system index scores
(Figure 5).
These excellent scores are not replicated in
the Cisuralian (early Permian) Bone Springs
and Ordovician Simpson petroleum systems,
which are of significantly lower quality (Figure 5).
This example highlights the ability of the index
to discriminate between different petroleum
systems within a basin, and identify the truly
exceptional ones, and the ones with greater
associated risk.
Comparing the Qualities of Petroleum
Systems Globally
Unique insights into the nature of petroleum
systems can be gained through this global
database of petroleum systems, and by utilizing
the hierarchical index that we have defined.
Three groupings of petroleum systems were
defined when the average scores of petroleum
system processes were plotted against the
average scores of petroleum system elements,
globally (Figure 6).
1
0.95
Element Enhanced
High Quality
Process Enhanced
0.9
0.85
Petroleum System Process Index
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
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0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Petroleum System Element Index
Figure 6> A cross plot of the petroleum system element index score against the petroleum system process index score for the global
population of basins. This plot is divided into three domains: those where elements enhance the index score; those where processes
enhance the index score; and those where both are of high quality.