Exploration Insights | 13
WHAT ’ S NEW IN NEFTEX ® INSIGHTS
EVOLUTION OF SOURCE-TO-SINK MAPS
We have updated 24 of the 52 time slices currently available , and added two new ones in the Cretaceous . These new time slices are also delivered unreconstructed to present-day geography , in order to integrate source‐to‐sink in your workflows .
The hydrocarbon potential of the Late Cretaceous , post-rift stratigraphy on the Equatorial and South Atlantic Margins of Brazil is often overlooked , because discoveries to date are focused in syn-rift , pre-salt plays . To assess the temporal and spatial variation of Late Cretaceous coarse-grained siliciclastic rocks along the South American margin , we employed Neftex ® understanding of Cretaceous paleoclimate and paleodrainage .
Exploration Handbook | 25
By: Andrew Davies
WHAT ARE PALEOCLIMATE MODELS?
Climate models are 4-dimensional computer simulators capable of reproducing the Earth system,
including the atmosphere (e.g. wind strength), hydrosphere (e.g. ocean currents), biosphere (e.g. land
plant productivity), cryosphere (e.g. sea ice concentration), and lithosphere (e.g. soils) (Figure 1). They
do this by identifying and solving equations that describe the basic physical laws that govern how the
Earth system behaves. The resulting climate simulations have a high degree of reliability and accuracy
(Figure 2).
Climate models were originally developed to predict the weather and the impact of future climate
change, but they can also be used to simulate past conditions. In this context, they are known as
paleoclimate models, even though the underlying climate simulator is the same.
Paleoclimate models have revolutionized our understanding of the Earth system (Haywood et al.,
2019). When applied to exploration, they allow us to use a robust, physics-based approach to test our
conceptual exploration models (e.g. Barron, 1985). This is because climate has a strong influence on
sedimentary systems and, in turn, many aspects of petroleum
systems. The information paleoclimate models provide can,
therefore, be used to predict whether source rocks, reservoirs,
and seals are likely to have been deposited at a given location
and time. As an example, consider oolitic limestones; these
comprise some of the world’s most important reservoirs
and only form in shallow, tropical waters where clastic input
is limited. Paleoclimate models can tell us where these
conditions occurred back through geological time (e.g. Davies
et al., 2019; Michel et al., 2019) (Figure 3).
To generate a climate simulation, climate models need to be
given a set of input data, also known as boundary conditions.
The most important are the bathymetry of the seas and
oceans, the topography of the land, and the position of the
coastline. Climate models also require information on the
location of major lakes, the routes of major river systems,
the concentration of CO 2 in the atmosphere, and the level of
incoming solar radiation (Figure 1). For paleoclimate studies,
the generation of reliable boundary conditions requires
significant effort, involving the compilation and interpretation
of large sets of diverse data to develop a plate tectonic model,
paleogeographic maps, and paleo digital elevation models.
Luckily, this is what Neftex ® has been undertaking for the past
two decades!
Shortwave radiation
There are many different types of climate models. The
simplest models are only able to simulate a single aspect
of the climate system. For example, atmospheric general
Longwave
radiation
Definitions
Paleoclimate simulations
are the outputs of climate
models.
Observed Versus Simulated Mean Annual
Sea Surface Temperature
Atmosphere
Above> An example paleoclimate
simulation — as shown under the tear.
These can be used to better understand
exploration potential.
Paleoclimate models
are numerical simulators
capable of reproducing the
climate.
PALEOCLIMATE MODELING CONCEPTS
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Sea Ice
e
h
e S
n
tio
eta
g
Ve
et
Ic
Soil
Paleoclimate Models in Exploration
R 2 = 0.9847
20
15
10
5
Heat & Gas
Exchange
© 2020 Halliburton
0
Ocean
-5
0
-5
Lithosphere
©
20
20
n
to
ur
llib
Ha
Figure 1> Diagrammatic representation of a fully coupled atmosphere and ocean general circulation model. Modified from Dippe et
al., 2018.
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10
15
20
25
30
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Observed SST (°C)
Figure 2> Comparison between observed sea surface temperatures (SST)
in the modern ocean and those simulated by the climate model HadCM3.
Although there are discrepancies, overall, the model is doing an excellent job of
reproducing the ocean temperature. (n=41088).
Boundary conditions are
the inputs prescribed by
the modeler. Examples
include bathymetry,
elevation, incoming solar
radiation, and composition
of the atmosphere.
24 | Halliburton Landmark