Rodney Stewart, age 11, of Bethlehem, Pa., for his question:
HOW DO SCIENTISTS KNOW WHERE TO LOOK FOR OIL?
The earth is a storehouse of many treasures. Gold, iron, copper, salt and hundreds of other substances buried beneath its surface are sought after and used by man. But few of these are as important to us today as is petroleum. Formed in the earth by plants and animals that lived more than a million years ago, petroleum and its byproducts are becoming increasingly important and, unfortunately, increasingly scarce.
The first commercially successful oil well in the United States was drilled in Titusville, Pa., in 1859. The man who planned and supervised the work was Edwin L. Drake. In those days searching for oil was a rather unscientific process, and the best places to find the precious liquid were in spots where it had seeped through the surface of the earth's crust. When attempts to collect the seepage proved unsuccessful, Drake proposed drilling a well for oil in much the same manner as you would drill for water.
Locating oil by guess and by gosh was a lot of work, and most of the time the drillers ended up with nothing for their labor. As time went on, however, oil hunters began keeping records of wells drilled. Information on each well was checked against other drillings. From these early records the science of petroleum geology was born. And oil hunters discovered that knowing something about the origin of oil and the rock layers it was found in could increase the chances of drilling a profitable well.
Prospecting for oil is a complex task. Even with the latest scientific knowledge and equipment, only about one out of nine wells drilled in a new area will produce oil. Geologists, photo geologists, geochemists, paleontologists and geophysicists are a few of the scientists and technicians needed to locate a prospective site.
Photo geologists study aerial photographs to find likely looking rock formations that may give clues to possible oil bearing structures below the surface. Ground based geologists make preliminary tests, and if the results look good more scientists loaded with sensitive instruments move in to make below surface tests. A gravimeter is used to measure the force of gravity. Another instrument, the magnetometer, measures the strength of a magnetic field. And the seismograph gathers information about man made mini earthquakes. Data from these and other instruments help paint a clear picture for modern oil¬ seekers but nothing is ever sure. Drilling is necessary to see if the picture is complete.
Before we were caught in the energy crunch, many oil fields were abandoned as exhausted, when actually only part of the oil had been removed. Conservation minded oil companies are now devising methods that will bring more oil out of old wells. They are also working on schemes that will help make new wells more productive.