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

              VOL. 26 NO. 6
FOR THE FACULTY AND STAFF OF THE UNIVERSITY OF MlAivîî
MARCH 1986
Study of the past aids search for oil
BY JACK McCUNTOCK
A SHORT WALK OUT INTO FLORIDA RAX 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 University’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 subtle 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 modem 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, “What we’re looking at here is lime muds. For a long time nobodyr 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" hav e 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 say s 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, “"tears ago, in East Texas, they-found oil in what’s now- called Quitman Reid. 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 modem sand grains, thought knowing about them might be useful.
“And he thought the reservoir in Quitman Reid 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 modem examples have a different direction—they- 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 w-as
Bob Ginsburg, director of the Comparatile Sedimentology Laboratory on Fisher Island, with a limestone formation. By understanding the formation of modern limestone, geologists may know ivhat to look for when searchingfor oil.
right. He told me later it saved the company- millions of dollars.”
Ginsburg smiled. “If it were always that simple, there’d be no problem finding oil. That one was partially' luck. But it did w ork”
Ginsburg conducts several such week-long seminars each year A thousand oil -exploration geologists from all over the 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 w-ho 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 Go. who supervises six exploration geologists.
“And then.” said Ginsburg, “if you drill in one place and
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