16 | Halliburton Landmark
suggestive of glacio-eustasy as the key driving
mechanism, even in episodes of Earth history,
such as the Cretaceous, often typified as having
“greenhouse” climates.
CONCLUSION
An understanding of eustasy is important
because it contributes to the sequence
stratigraphic organization of sedimentary
successions, and helps with understanding
the stratigraphic variability of the geological
record. However, the isolation of the eustatic
signal from the sedimentary record presents a
significant challenge, which may be overcome by
a synthesis of globally derived estimates of sea-
level change.
The analysis of short-term sea-level change
within intervals that have traditionally typified
“greenhouse” (Ray et al., 2019) and “icehouse”
(Rygel et al., 2008) worlds reveals new and
unexpected insight into the role of climate
and sea-level in governing the nature of the
stratigraphic record. Accurate estimates of sea-
level change are an important input for forward
stratigraphic modeling, and provide a means of
predicting reservoir-scale facies variability. They
also help to constrain the other contributing
factors, besides sea-level, to stratigraphic
architectures.
Robust limits to the magnitude of short-term sea-
level change allow more fundamental questions
to be addressed, such as, what is the relative
importance of aquifer-, thermo-, and glacio-
eustasy to the total amount of eustatic change?
Armed with a knowledge of the climate from
Earth systems science and the magnitude of
sea-level change, climate models can be used to
test preconceived ideas, such as “aquifer-eustasy
is the main driver of sea-level change during
greenhouse times”. Results from this study’s
Cretaceous climate models cast significant doubt
on the importance of aquifer-eustasy as the
dominate driver of short-term sea-level change,
and indicate that sea-level is mostly controlled by
the volume of icecaps (Davies et al., 2020).
For the majority of the Phanerozoic, no
synthesis of the magnitudes of short-term sea-
level changes has been made, in spite of the
availability of numerous well-reasoned estimates
Exploration Insights | 17
for many episodes of sea-level change (e.g.
Silurian — Johnson, 2006; Cenozoic — Miller et
al., 2020). Similarly, long-term sea-level change
remains to be addressed by means of a detailed
synthesis approach. Thus, while a robust method
for establishing eustasy has now been arrived at,
much work remains to be done to fully determine
the ups and downs of Phanerozoic sea-level.
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AUTHORS
Dr. David Ray, Stratigraphy Advisor, Halliburton
Landmark
David joined Neftex ® Insights in 2008, and
has had a number of roles, mostly focused on
biostratigraphy and the development of the Neftex Sequence
Stratigraphic Model. He holds a BSc degree in Geology with
Paleontology from Imperial College, U.K. and a PhD degree
in Event Stratigraphy from the University of Cincinnati, USA.
David is a Research Fellow at the University of Birmingham,
UK, and a member of the International Subcommission on
Silurian Stratigraphy.
Dr. Mike Simmons, Technology Fellow, Halliburton
Landmark
Mike is responsible for the investigation into
innovation in geoscience related to hydrocarbon
exploration. Previously, he was Earth Model Director at Neftex
and before that worked for BP, Aberdeen University, and
CASP at Cambridge University. His main interests are applied
stratigraphy and the geology of the Tethyan region. Mike
teaches at a number of universities, where he promotes the
value of sequence stratigraphy in the exploration process.
Dr. Frans van Buchem, Principal Advisor
Geoscience, Halliburton Landmark
Frans works as a G&G researcher with a focus
on the integration of Neftex ® geological insights
within the Landmark interpretation software suites. He has
30 years of industry experience, including various research
and management positions in Exploration and Production
at the French Petroleum Institute (IFP), Maersk Oil, and Elf-
Aquitaine. He is a specialist in sedimentology and sequence
stratigraphy, possessing in-depth knowledge of the carbonate
petroleum systems of the Arabian Plate. Frans holds MSc
degrees in Biology and Geology from Utrecht University,
Netherlands, and a PhD degree from Cambridge University,
UK.
Dr. Graham Baines, Manager of Assisted
Interpretation, Halliburton Landmark
Graham leads the Assisted Interpretation team
at Halliburton Landmark, which develops data-
driven tools to help geoscientists interpret the sub-surface.
Graham joined Neftex in 2011, and has had a number of roles,
including Geoscience Advisor, Geosolutions team lead, and
Geodynamics team lead. He was previously a postdoctoral
fellow at the University of Adelaide, Australia and has a
doctorate in Geophysics from the University of Wyoming,
USA.
Dr. Andrew Davies, Geoscience Advisor,
Halliburton Landmark
Andrew’s main role is to help develop the next
generation of geoscience tools for use in the oil
and gas industry. Previously, he held various roles at Neftex,
including senior research and development geoscientist, and
Head of Innovation, acting as part of the Neftex leadership
team. Andrew also holds the position of senior visiting
research fellow at the University of Leeds, UK.
Dr. Benjamin Gréselle, Product Owner of Earth
Systems Science, Halliburton Landmark
Benjamin is responsible for the development
and strategy of Neftex ® global-scale products.
These provide a global context for the prediction of
primary petroleum system elements, built on Earth system
modeling, including topography, drainage, source-to-sink, and
paleoclimate. Benjamin joined Neftex as a regional geologist.
Previously, he carried out research for Statoil on carbonate
field analogues in Mexico. Benjamin holds PhD and post-
doctorate degrees in Carbonate Sedimentology and Sequence
Stratigraphy from the University of Lyon in France.
Christopher Robson, Senior Geoscientist, Earth
Systems Science, Halliburton Landmark
Chris is a Senior Geoscientist on the Earth
Systems Science team at Neftex ® . He is
responsible for investigating, capturing, and applying
climatic proxy data. Chris has been at Neftex for 8 years, and
previously worked on the Biostratigraphy team and the Tethys
regional team. He has a Master’s degree in Geoscience from
Royal Holloway University of London, UK.
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