Figure 1: The Face of the Matanuska Glacier outside of
Palmer Alaska. The Matanuska is a good example of a
small retreating alpine glacier. Fractures in the glacier allow
meltwater to carry rock and sediment to the glaciers base.
Using LiDAR as an Oil and
Natural Gas Exploration Tool
D
oes the upward propagation of
faults, fractures and sub surface
features create an expression on
the surface of the earth? Faults, fractures
and sub surface features buried in
many cases thousands of feet below the
surface of the earth are very important
to the petroleum geologist. Faulting can
create porosity and confine petroleum;
sub surface structures also contain oil
and natural gas. LiDAR imagery can
BY CHUCK KNOX
accurately scan the earth’s surface and is
readily available to the petroleum geologist. Can the petroleum geologist use
LiDAR derived data to locate the upward
propagation of these expressions on the
surface in drift covered areas? and can
the petroleum geologist use the information to improve the odds of successfully
drilling oil and natural gas wells?
The question of does the sub surface
reflect on the surface has been asked
and debated since the birth of modern
petroleum geology. W.S. Blatchley, State
Geologist of Indiana in the early 1900’s,
noticed that most of the new drilling
for oil in the Selma-Parker oil field was
in the low lands and stream valleys.
Blatchley was one of the fathers of
modern petroleum geology and he was
very skeptical and even dismissive of the
drillers actions; he noted that there is no
known correlation between the surface
and the subsurface, questioning their
choices on locations. The drillers were
practical men who could care less about
the emerging science of petroleum
geology (much less Blatchleys opinion)
they saw a correlation between surface
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Figure 2: Standing on one of the terminal moraines of the Matanuska you can see the current location of the ice face and the debris field
left behind. The Matanuska has been retreating for 1000’s of years and is a fraction of its original size. Kames and Eskers formed under the
glacier and end moraines on the flanks have left a highly irregular and chaotic surface.
conditions and oil production and they
exploited that correlation.
Aerial photography was used as a tool
during WWII to detect enemy troop and
armament movements. After the war
the technology was successfully used
by geologists as a method of remote
sensing. Out of this came the first group
of photogeologists, these were bright and
talented scientists who saw that there
was a correlation between the surface
and the subsurface. Photographs of the
earth’s surface could now be examined
with stereoscopic lenses. Using this new
technology, the photogeologist could
easily see radiating stream patterns over
sub surface structural highs and long
lineaments over faults and fractures.
A great body of work was compiled by
this group from the late 1940’s to the
1970’s. With the advent of the computer
age and the rise of seismic surveys the
information photogeologists provided
in the exploration of oil and natural gas
diminished. Digital data was becoming
increasingly valuable, the observations of
the photogeologist was an interpretation
of the earth’s surface by an individual
which was not easily reduced into digital
form. By the early 1980’s photogeology
was used very little as an oil and gas
exploration tool.
That will change with the advent of
the modern LiDAR survey. The surface
of the earth can now be scanned and
the data placed into digital form. We
can use the principals designed and
developed by the photogeologists of
the 1940’s and 1950’s and apply these
principals to the modern LiDAR derived
data. No longer is the information
a result of an interpretation of an
individual it is digital data that can be
used for visualization or layered into
queries. We can now digitally see what
the drillers of the Selma-Parker field saw
in 1903; there is a correlation between
the surface and the sub surface.
Geomorphology is the study of the
earth’s surface and here in the upper
Midwest the surface of the earth was
sculpted by numerous advances and
retreats of the great continental glaciers.
Thick layers of drift were left behind as
the glaciers melted. Sub surface structures
along with faults and fractures did
influence the conditions controlling the
melting of the glaciers which affected the
resulting topography. Fractures in the ice
allowed meltwater to drain to the glaciers
base and create streams and channels
under the glacier. Kames and Eskers
developed under the ice. It is these features
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that we see today; erosional forces have
muted their appearance but they are still
there and we can model them with LiDAR.
What we are finding is the surface features
created by a retreating glacier can and
often do correlate to sub surface structures
that have produced oil and natural gas.
Case studies
The Illinois Basin has proved to be an
excellent area to correlate LiDAR derived
surface features with oil production.
The surface is drift covered from the
Wisconsin and Illinois glaciations and
oil development has continued since
the early 1900’s. The Illinois Height
Modernization Program (ILHMP) has
done a nice job of making the available
LiDAR data easily downloadable. Many
of the Illinois counties have LiDAR
surveys but regrettably some important
counties do not. Using LiDAR as an
exploration tool is in its infancy, but we
do have a basic set of principals available
which were developed by the photogeologists in the 1950’s and 1960’s. Most
of the original photogeology principals
applicable to LiDAR data use stream
flow. LiDAR derived digital elevation
models and flow accumulation maps
are much more precise than the aerial
photographs used by the photogeologist
of the past era.
Preliminary work with Indiana LiDAR
data has shown that sub surface faults
and fractures often manifest themselves
as areas of higher slope angles on the
surface. Measuring slope angles is
specific to modern LiDAR surveys and
was not used previously. After study of
the Illinois data the same correlation
does exist, higher slope angles are
evident over many areas of Silurian oil
production. The Kincaid and Cooks
Mills oil fields are a good example of the
Figure 3: The Kincaid oil field is a good example of the correlation of oil production and
higher slope angles. Silurian oil production correlates with the higher slope angles. A smaller
pool of Devonian oil production is from an area of lower slope angles.
“ hat we are finding is the surface features
W
created by a retreating glacier can and often
do correlate to sub surface structures that have
produced oil and natural gas.
correlation between higher slope angles
and oil production. Preliminary work
on sub surface structures in Indiana
has shown that differential compaction
over reef structures can and often
does extend to the surface and can be
modeled with digital elevation models
and flow accumulation models. The
Nashville and Elbridge oil fields are good
examples of these structures.
The Kincaid oil field is in Christian
County, Illinois. Christian County is
located on the southern flank of the
Sangamon arch and has had recent oil
development. Wells are mostly Silurian
”
in age with some Devonian production.
A LiDAR survey was flown between
12/2014 and 03/2015 by Digital Aerial
Solutions using a Leica ALS70. Slope
angle maps using ArcGis 10.3 were created from a terrain data set. 12 divisions
were used with quantile classification and
a green to red color ramp. Green is lower
slope and red is higher slope. Quantile
places an equal amount of data in each
division and results in a good signature
of the higher slope angles in relatively
low slope areas. Natural breaks or “Jenks”
classification is more appropriate for
areas of high slope angles. As evident in
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Figure 4: The Cooks Mills oil field is another example of the correlation
of higher slope angles and the production of oil in the Illinois Basin.
Figure 3 much of the Silurian oil wells
are in areas of red (higher slope).
The Cooks Mills oil field, Figure 4
is another good example where oil
production and higher slope angles
correlate. The Cooks Mills oil field is in
Douglas County, Illinois. The LiDAR
survey was flown by AeroMetric Inc.
using an Optec Gemini and Leica
ALS70 and was available 2012. A terrain
data set using ArcGis 10.3 was also used
for the Cooks Mills study with 10 divisions and the same green to red color
ramp and quantile classification as the
Kincaid study. Terrain datasets are very
useful due to their scalability and ease of
visualization of the Earth’s surface. The
triangulated surface of the slope angle
map is easy to interpret.
The Nashville oil field, Figure 5 is in
Washington County, Illinois. Surdex
Corp. flew this survey in 2015 using
a Leica ALS70-HP. Oil is produced
from Devonian sediments that are
draped over a Silurian reef. Differential
compaction has allowed sediments to
drape over the hard reef core. Sediments
on the flank of the reef are lower in
elevation than the same aged sediments
over the core of the reef. This elevation
change extends upwards through the
geologic column with structural changes
having a positive impact on the surface.
The Nashville oil pool is one of these
reefs that evidence of the differential
compaction can be modeled on the
surface. Over the history of the discovery
of the reefs in the Illinois reef trend a few
were discovered by locating drainage
radiating away from a central point. By
using LiDAR derived digital elevation
models and digitally created flow accumulation maps we can locate areas with
structural highs and radiating drainage
patterns. This DEM was created using a
green to red classified color ramp. The
raster is 65% transparent and overlies a
hill shaded raster giving a 3-dimensional
model. There is clearly an area of higher
elevation over the reef and the radial
drainage away from the reef is modeled
nicely by the flow accumulation map.
The Elbridge oil field is also a Silurian
reef with oil production from Devonian
sediments draped over the reef core.
The Digital elevation model and flow
accumulation on the surface correlate
nicely with the oil production. The
Elbridge oil field, Figure 6 is in Edgar
County, Illinois. The LiDAR survey was
flown by AeroMetric Inc in 2012 using
an Optec Gemini and Leica ALS70. The
Elbridge is the eastern most reef in the
Illinois reef trend and located under
the Westfield moraine. The Westfield
moraine is the terminal moraine of
the Wisconsin glaciation. To the south
west is Illinoisan glaciation and to the
northeast is Wisconsin glaciation. When
looking at the DEM of the Elbridge
you can see the influence it has on the
moraine, the Westfield moraine expands
southward and oil production lies
below this area of expansion. As in the
Nashville, flow accumulation data shows
stream flow radiating away from the area
above the reef core.
Conclusions
To correlate the surface and the sub
surface an intimate knowledge of the
sub surface is needed. Gathering this
information is much easier in areas that
have been developed by the oil and gas
industry. LiDAR derived surface models
when compared to known sub surface
structures will be powerful tools for any
oil and natural gas exploration program.
Large areas of the country can be looked
at quickly and easily and if one knows
what LiDAR models are more likely
to produce oil, much acreage can be
excluded. On a more localized program
the LiDAR surface models over a known
oil producing region can be used to
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expand into areas with the right criteria
that have not previously been drilled.
LiDAR is already being used in the
oil and gas industry to locate locations
suitable for placing pipelines and
drilling locations. Most digital elevation
models are using LiDAR data and thus
by default the industry is using LiDAR.
Using LiDAR as an exploration tool is
new to the oil industry.
One of the basics of petroleum
geology is to accurately locate the depth
of sub surface geologic formations.
Measurements derive from the surface
and an accurate survey derived from
LiDAR data will become the standard
for the industry. LiDAR derived surface
elevations will become the foundation for
all the petroleum geologists mapping. The
use of LiDAR derived slope angles, digital
elevation models and flow accumulation
models will become a valuable tool in the
exploration for oil and natural gas.
The more we learn about the correlations of the geomorphic conditions
on the surface of the Earth and the
geological conditions of the sub surface
the more valuable LiDAR data will
become as a tool in the exploration of oil
and natural gas. The photogeologists of
the 1950’s and 1960’s built a substantial
understanding of the correlation of
surface and sub surface. Modern digital
LiDAR data will allow us to take the
next step in understanding the processes
that shaped the surface of the Earth and
in turn use that understanding for the
continuing hunt for oil and natural gas.
Chuck Knox is the owner of Knox Geological
LLC. He is a graduate of Western Illinois
University and has spent most of his adult
life studying geology and the history of
petroleum exploration. He has been working
with LiDAR data sets and their relationships
to known oil and gas fields since 2011.
Figure 5: The Nashville oil field was discovered in 1975 and has produced over 4.5mmbo.
Oil is produced from Devonian sediments draped over a known Silurian reef, evidence of
the reef can be seen on the surface using LiDAR derived flow accumulation data and a
digital elevation model.
Figure 6: The Elbridge oil field produces oil from Devonian sediments draped over a Silurian
reef. The Elbridge lies under the Westfield moraine which is the terminal moraine of the
Wisconsin glaciation in Illinois. The Elbridge was discovered in 1949 and had produced
1.5 mmbo by 1972.
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