Natural gas is mostly a mixture of methane, ethane, and propane, with methane making up 73% to 95% of the total. Often found when drilling for oil, natural gas was once considered mainly a bother. When there were no uses or markets to sell natural gas, it was simply flared (burned off) at the wellhead. Major flaring sites were sometimes the brightest areas visible in nighttime satellite images. Today, however, the gas is mostly injected back into the ground for later use and to encourage greater oil production
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