For as long as he can remember, David
Houseknecht has wanted to work in
Alaska for its “appeal of the wilderness
and the frontier adventure.”
He would have been content helping
to build the Trans-Alaska Pipeline System
in the 1970s, but a professional career in
geology began to beckon, ultimately taking
him to the U.S. Geological Survey in 1992,
where he is currently a senior research
geologist.
Initially in charge of funding energy
research and resource assessments,
Houseknecht received a fateful telephone
call in 1995 from former USGS Research
Geologist Don Gautier, who asked him to
participate in a field session in Alaska.
“The word ‘yes’ came out of my mouth
before I could give it a second thought,”
Houseknecht recalled.
Gautier, working with a modest budget
to assess the North Slope’s petroleum
resources, wanted to show Houseknecht
that further research was essential
to rigorously and objectively evaluate
hydrocarbon potential.
Now, 26 years later, Houseknecht
has been awarded the Wallace E. Pratt
Memorial Award for the best AAPG Bulletin
article in 2019, which outlines a detailed
geological framework of the North Slope to
explain the geology of recent discoveries
and delineate the potential for future
discoveries.
Building the Framework
Since his first field season in Alaska
in 1995, Houseknecht has spent nearly
every summer on the North Slope mapping
and leading field parties, eventually being
named chief of the Alaska Petroleum
Systems Project – which serves to build a
robust geological framework of the North
Slope based on sequence stratigraphy
and basin evolution and provides resource
assessments. His work, which builds on the
research of his predecessors and peers in
state and federal government, has become
a foundation – and a trusted guiding light –
for the industry.
Over the last 20-plus years,
Houseknecht has meticulously linked
invaluable pieces of North Slope geology
that have helped lead to substantial
discoveries, including the 1.2-billion barrel
Pikka discovery in a stratigraphic trap in the
Nanushuk Formation by Armstrong Oil and
Gas in 2013.
“He was one of the first to recognize the
potential of the Nanushuk Formation,” said
AAPG Member Bill Armstrong, CEO and
president of Armstrong Oil and Gas. “His
field work and regional perspective were
extremely helpful to us in our exploration
efforts. The Nanushuk has evolved into one
of the best and most prolific exploration
plays in the world.”
The Pikka discovery prompted
Houseknecht to reassess resources in
the Cretaceous Nanushuk and Torok
formations, including the National
Petroleum Reserve – Alaska and adjacent
state lands and state waters. In 2017,
the updated assessment estimated a
mean value of undiscovered, technically
recoverable resources at 8.7 billion barrels
of oil and 25 TCF of natural gas.
The Pikka discovery also prompted
ConocoPhillips to return to its long-held
leases in NPRA and find up to 750 million
barrels of oil – also in stratigraphic traps in
the Nanushuk Formation in its 2016 Willow
discovery.
“No one thought these Nanushuk
stratigraphic traps could hold that much
oil,” Houseknecht explained. “Over 150
wells had penetrated the formation, going
down into deeper targets, before the
Pikka discovery was made. That is pretty
remarkable.”
Geological ‘Breadcrumbs’
The newly discovered potential on
the North Slope prompted Houseknecht
to write, “Petroleum systems framework
of significant new oil discoveries in a
giant Cretaceous (Aptian–Cenomanian)
clinothem in Arctic Alaska,” published in the
AAPG Bulletin in March 2019.
It is a regional synthesis of why the
Nanushuk play works and is based on
decades of work by Houseknecht and other
USGS and state researchers, including Ken
Bird, Tom Ahlbrandt, Curt Huffman, “K”
Molenaar and Dave LePain.
In his paper, Houseknecht points out the
geological “breadcrumbs” that led to recent
discoveries beginning with the U.S. Navy’s
exploration of the North Slope in the 1940s.
He explains that oil-rich source rocks
and the Cretaceous clinothem drape across
Alaska’s Barrow Arch – a structural hinge between the Colville foreland basin and the
Beaufort Sea rifted margin. Furthermore,
stratigraphic traps lie in a favorable thermal
maturity domain along multiple migration
pathways that span more than 10,000
square miles.
Sediment from the Chukotkan orogen
in Russia, which filled the western Colville
basin and spilled over the Beaufort rift
shoulder, formed east- and north-facing
shelf margins. Two stratigraphic trap types
can be inferred in Nanushuk basal topsets
in the eastern part of the clinothem – both
of which include stratigraphically isolated
sandstone sealed by mudstone.
In the Nanushuk and Torok formations,
Houseknecht believes that hundred-millionto
billion-barrel oil accumulations remain to
be discovered both in and outside of NPRA.
Greg Wilson, AAPG Member and a
former exploration manager of operations
and technology at ConocoPhillips
Alaska, said Houseknecht’s work is “a
comprehensive and definitive synthesis
of a play of contemporary significance to
industry.”
His sentiments are underscored by
AAPG Member and retired geoscience
adviser for ExxonMobil David Puls: “It is
unique … to see a government scientist
so committed to the quest of finding
hydrocarbons in the rocks of the North
Slope. He is an advocate for industry
progress, but balances that so well with the
desire for resource stewardship required of
government agency representatives.”
In 2018, the U.S. Department of the
Interior honored Houseknecht with a
Distinguished Service Award for his
accomplishments.
Renewed Interest in Alaska
The USGS’ updated assessment of the
Nanushuk and Torok formations combined
with recent significant discoveries have
brought about a resurgence of interest
in Alaska’s North Slope. A lease sale in
NPRA originally slated for early 2021
(and currently under a “pause and review”
process by the Biden administration) was
expected to be a land rush of sorts.
“We have been fortunate that the
industry, over the last decade or so, has
used the work we have published as
guidelines to explore the Nanushuk and
other formations,” Houseknecht said. “What
is rewarding to me is seeing this work
applied and acknowledged.”
Despite the administration’s
moratorium on lease sales on federal
land, Houseknecht believes the industry
will continue to thrive in Alaska for the
foreseeable future and that the USGS’s
work will be used by the Department of the
Interior and Bureau of Land Management in
reviewing oil potential across NPRA.
“I think there will continue to be
exploration and development in northern
Alaska and in Cook Inlet, for sure. There’s
no question that the other step is gas
exploration in northern Alaska in the
next decade if a gas marketing system
is developed,” he added. “Gas is a huge
resource there but all gas on the North
Slope is stranded. It makes sense that
a transition to gas exploration and
development would be a logical move
toward a more environmentally benign
hydrocarbon resource.”
As a recipient of the J.C. “Cam” Sproule
Award in 1987 for an AAPG Bulletin
paper on sandstone reservoir porosity,
Houseknecht views his two awards as
“bookends” in his career – quickly adding,
“not that I am quitting today.”
“I am thrilled with being awarded
the Pratt award,” he said. “To me, it is
acknowledgement that my work has been
worthwhile and a value to the industry.”