Petroleum Prospecting and Technology

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PETROLEUM PROSPECTING AND TECHNOLOGY

PETROLEUM PROSPECTING AND TECHNOLOGY. Residents of North America knew what oil was and where to find it long before they had enough uses to make extracting it a viable concern. Evidence suggests Native Americans and early European settlers skimmed oil seeps, where oil surfaces of its own accord, and used the viscous liquid for medicinal purposes as a purge and balm, for lamp fuel, and for machinery lubrication. Spanish explorers used it to water proof their boats and boots.

Not until 1859, near Titusville, Pennsylvania, did oil extraction become economically feasible, launching an industrial explosion. Area residents already knew how to collect oil from a seep by damming the nearby stream and skimming the resulting pool. The largest operation produced twenty to thirty barrels of oil in a season, not enough to be cost effective.

Principals of the Seneca Oil Company believed that oil, if extracted in enough quantity, could be sold primarily as a high-quality illuminant. Edwin Drake, hired by Seneca to extract the oil, borrowed the concept of drilling from salt drillers. To get through the unconsolidated gravel in the flats around Oil Creek, he invented the drive pipe, made of cast iron with ten-foot joints that protected the upper hole as it was created. Tools could then be lowered through the pipe to work on the shale bedrock. Drake's well came in on 27 August 1859, and this discovery of the means by which to extract large quantities of oil touched off the first oil boom.

Through the latter half of the nineteenth century, the search for oil expanded. However, the primary method of finding oil required locating surface evidence, including oil seeps, paraffin dirt (soil with petroleum elements), and sulfurous gases. People drilling for salt and water also occasionally discovered oil.

Despite growth in the number of wells and some drilling enhancements, the oil industry did not really burgeon until the early 1900s. The invention of the automobile catapulted gasoline into the industry's leading seller. Ships and trains that had previously run on coal began to switch to oil. The Santa Fe Railroad went from one oil-driven locomotive in 1901 to 227 in 1904. Petroleum also served as the fuel source for airplanes. By then, many of the obvious oil locations had been drilled and finding oil had become more difficult. Oil prospectors had to develop prospecting methods beyond the obvious. At the turn of the century, Patillo Higgins was convinced that a salt dome, Spindletop, near Beaumont, Texas, harbored crude oil beneath it. Higgins' recognition that a specific geological structure may harbor oil was one of the first geologic contributions to prospecting. Higgins was proved correct about salt domes when Spindletop began producing oil in 1901 in what was then the single largest producing well. Despite his success, however, geology still played a limited role in petroleum prospecting. The first geologist was not hired by an oil company until 1911. It wasn't until 1913, when Charles Gould of the Oklahoma Geological Survey wrote a paper outlining the

relationship between rock structure and oil and gas, that petroleum prospecting began to really explore the uses of geology. By 1915 oil companies were hiring most of the geology graduates at the University of Oklahoma.

Geologists began determining likely deposit areas based on surface ground and underlying rock. The search for salt domes saw the introduction of the torsion balance, one of the earliest geophysical instruments used in petroleum prospecting. The torsion balance measures the density of rock beneath the earth's surface by measuring the gravitational field. The gravitational force varies according to differences in mass distribution at the earth's surface. Salt domes are associated with light gravity. The Nash Dome, in Brazoria County, Texas, discovered with a torsion balance in 1924, hosted the first oil uncovered by geophysical means. Pendulums were also used to record variations in the earth's gravity. Gravity meters superceded pendulums, although those were not very effective until the mid-1930s.

Geology is the driving force in petroleum prospecting. Geologists gather information above ground to determine what lies underneath. They look for evidence of source rock, reservoir rock, and structural traps. Oil typically exists in nonmagnetic rock, near salt, and in faults and folds in the earth's crust. Geologists trail magnetometers during aerial surveys to measure magnetism over a large area. Field balances are used in the surface to measure magnetism in a specific location. Geologists also use sophisticated equipment to send sound waves into the earth, analyzing the wave return to determine the type and depth of different rock layers. This allows them to locate the porous rock strata in which petroleum most likely resides. "Sniffers, " high-tech devices that act like a "nose" are also used to detect traces of hydrocarbon gases that escape from below-surface oil deposits. To analyze the rock fragments brought to the surface with the mud during drilling, geologists create "mud logs."

Despite technological advances in prospecting, drilling is still the only method to confirm oil's existence. The search for oil is still speculative. Wells drilled more than a mile from existing production, known as wildcat wells, have a one in ten chance of success. Wells drilled in un-proven frontiers, "rank wildcat wells, " have a one in forty chance of success.

BIBLIOGRAPHY

Conoway, Charles F. The Petroleum Industry: A Non-Technical Guide. Tulsa, Okla.:PennWell, 1999.

Economides, Michael, and Oligney, Ronald. The Color of Oil: The History, the Money, and the Politics of the World's Biggest Business. Katy, Texas: Round Oak, 2000.

Owen, Edgar Wesley. Trek of the Oil Finders: A History of Exploration for Petroleum. Tulsa, Okla.: American Association of Petroleum Geologists, 1975.

Stoneley, Robert. Introduction to Petroleum Exploration for Non-Geologists. New York: Oxford University Press, 1995.

TerriLivermore

T. L.Livermore