Comment: 00:40 - 02:00 (01:20)
Source: Annenberg/CPB Resources - Earth Revealed - 3. Earth's Interior
Keywords: introduction, "oil well", "James Sadd", "Soviet Union", drilling, oil, well, "Earth's interior"
Our transcription: Each of these oil wells is producing about 100 barrels of oil every day.
Oil from wells like these has fueled the engines and economies of the industrialized world for over a century; but for geologists, oil wells serve an equally important function.
They act as vital windows to the Earth's interior.
There are limits, however, to how far these windows allow us to see.
These wells are about a kilometer and a half deep, and the deepest oil and gas wells penetrate the Earth's crust to about 8 kilometers.
The world's deepest well is now being drilled in the Soviet Union.
Designed a scientific laboratory, it has a planned depth of 15 kilometers which seems like a long way down until we consider that this is only one quarter of one percent of the distance to the center of the Earth.
Also, drilling deep wells involves a technological complexity that rivals space exploration.
The deep Soviet well, for example, penetrates rocks at pressures 5,000 times that of the Earth's surface and at temperatures of 300 degrees centigrade.
Although progress is being made, there are tremendous technical obstacles that must be overcome before wells like this can be extended and offer geologists a direct view of the Earth's interior.
Geology School Keywords