Natural Gas
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Oil wells themselves are a source of natural gas, for there is some gas in every oil field. Before World War II, the price of natural gas was so low that much of the gas produced with oil ("associated" or "casinghead" gas) was burned in the fields to get rid of it. As recently as 2005 Saudi Arabia flared 7 billion cubic feet of gas. This is still done in Nigeria, which does not have the necessary facilities to capture and use the gas. Most U.S. natural gas comes from wells that produce only gas. Natural gas is believed to have been formed under conditions similar to those that create oil, but the organic matter continued to change into lighter hydrocarbons, chiefly methane. When burned, natural gas has high heat content and produces fewer pollutants and less carbon dioxide than oil or coal. |
Figure 8 |
