Veritas, Vol. 26, No. 06, March 1986

              VOL26N0.6
FOR THE FACULTY AND STAFF OF THE UNIVERSITY OF NOAM
Study of the past
aids search for oil
BY JACK McCUNTOCK
A SHORT WALK OUT INTO FLORIDA BAY BE
tween the Florida Keys and the mainland. Bob
Ginsburg stood in saltwater up to his waist, talking
about limestone. Standing in the water with him in their
cut-offs, sneakers and T-shirts, were 18 oil-exploration
geologists from all over the world.
Limestone is being deposited in the Bay today,
Ginsburg tells them, just as it was being deposited during
the past two billion years all over the world If they listen
carefully and store away what they learn about these patterns and processes, someday it may help them discover
oil.
Ginsburg, who is director of the LTniversity's Comparative Sedimentology Laboratory on Fisher Island said,
"Most of the world's easy oil discoveries have already-
been made, such as the giant domes in Saudi Arabia that
are visible from the surface. Nowadays, exploration
geologists search for more subde traps, as they are called.
They can only be discovered by using all possible clues
from geology, geophysics, geochemistry and and the like.
"One clue in this is to understand more about the patterns of accumulation: the spatial arrangement of the
original deposits."
If a geologist can learn exactly how modern limestone
is being formed, then he or she may know what to look
for when exploring the ancient limestones. This is why
they- were all standing in the Bay listening to Ginsburg explain about lime muds and rocks.
Ginsburg sloshed a few feet farther in the Bay and said.
"WTiat we're looking at here is lime muds. For a long time
nobody thought these could become a reservoir for oil
and gas. but now research has shown that indeed when
they have the appropriate history, as they have had in
West Texas, they can be. More than half the world's oil
reserves are found in rocks like these in the Middle East.
Western Canada and West Texas."
Nobody says much about oil. What these geologists are
interested in is the limestones that will be formed from
these soft sediments. The process that was completed
millions of years ago in the Arabian peninsula or West
Texas, for example, is still underway here and can be studied by geologists today.
For instance, he said "\ears ago, in East Texas, they
found oil in what's now called Quitman Held The oil-
bearing limestone contained tiny lime-sand grains with a
distinctive, onionlike structure, called ooides. A geologist
there, remembering that we had studied similar modern
sand grains, thought knowing about them might be
useful.
"And he thought the reservoir in Quitman Held might
have been an ancient beach deposit and would be oriented east-west But when he came here and studied with
us in the Bahamas he learned that modern examples have
a different direction—rhey form at right angles to the
beach- They run north-south.
"He took this idea back to Texas and used it to guide
the drilling of additional wells, and lo and behold he was
Bob Ginsburg,
director cflbe
Comparative
Sedimentology
Laboratory on
Fisher Island,
with a limestone
formation. By
understanding
the formation of
modern lime-
Ginsburg smiled "If it were always that simple, there'd
be no problem finding oil. That one was partially luck-
But it did work."
Ginsburg conducts several such week-long seminars
each year A thousand oil-exploration geologists from all
over rhe world, representing every major oil company
have visited over the last dozen years to study the formation of limestone. Today, before long. Ginsburg would
have them wading through more waist-deep seawater
scooting along on their backsides in viscous mud plodding across a sweltering, mosquito-infested mangrove is
land and snorkeling in clear turquoise water
"Observing how limey sediments form is something
one can do in only a few places in the world today;" said
Andre Baumann. leaning on the railing of the rented diver
boat Baumann is a Dutch geologist who works for Shell
Netherlands.
"If you can look at how sediments are deposited today,
and how the deposits are shaped it can make your explorations more efficient" said David Hurd, a production
geologist for Shell Oil Co. who supervises six exploration
"And then." said Ginsburg. "if you drill in one place and
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