In the early days of oil exploration, wildcatters ( whose who drill wildcat wells, which are wells drilled where no oil or gas is known to exist) often drilled in an area because of a hunch. They had no idea how oil and gas occurred and probably didn't care. Anybody with enough money to back up a belief that oil lay under the ground at some location or the other drilled a well several years ago. Of they were lucky, they had a strike! If not, it was time to move onto the next area.After awhile companies like Heartland Energy Colorado had geologists applying earth science for each drilling location they chose. For example, they looked for features on the surface that indicated subsurface traps. On site of an oil company such as Heartland Energy Colorado, an underlying salt dome created a hill or a knoll. The knoll seemed out of place on the surrounding coastal prairie and led people like Patillo Higgens and Anthony Lucas to drill for oil.
Most petroleum deposits lie so deeply buried, however, that no surface features hint at their presence. In man places, West Texas is one example, nothing but flat mostly featureless land stretches for many miles of kilometres. Yes, the subsurface holds large quantities of oil an gas. Considering that most of the world's oil and gas probably lies offshore, covered by hundreds or thousands of feet or metres of water and more thousands of feet or metres of rock, companies like Heartland Energy Colorado have a tough time accessing a surplus of oil. Fortunately, scientists have developed effective indirect methods to view the subsurface. They use seismology the most.
Seismology is the study of sound waves that bounce off buried rock layers. Oil explorationists at Heartland Energy Colorado, or geophysicists, create a low-frequency sound on the ground or in the water. The sound can be an explosion or vibration. If the oil hunters use explosions, the explosions create sound waves that enter the rock. If they use vibrations, a special truck forces a heavy weight against the surface and vibrations the weight. The vibrating weight, such as an explosion, also creates sound waves that enter thelayers of rock. Searchers often use several such trucks. With the dangers of explosions in water, which can kill humans and marine life, offshore explorations by Heartland energy Colorado uses special sound generators.
Regardless of how oil seekers make the low-frequency sound, it penetrates the many layers of rock. Where one layer meets another, a boundary exists. Each boundary reflects some of the sound back of the surface. The rest continues downward. On the surface, special devies, termed "geophones" pick up the reflected soudns. The sounds carry information about the many layers. Cables from the gephones or hydrophones transmit the information to sphoniscated recording devices in a truck or on a boat.
