Natural gas is found underground, although sometimes it leaks to the surface.
Oil and gas are often found together in underground "traps". Oil floats on water. And, natural gas floats on oil. Because of these density contrasts, oil and gas rise in a reservoir until they are trapped at the highest point. When the trap is a fold like the one on the right, it can create a commercial accumulation underground.
In a case like this, it is possible to produce the oil and/or gas without producing any water, which is good for a variety of reasons. It is rare to find oil without gas, but it is not rare to find natural gas without oil.
Since 1978, the industry has learned how to produce natural gas from coals. This is called coalbed methane production, or CBM. Today, about 40% of our natural gas production in Colorado is from CBM.
Below is an example of natural gas leaking to the surface under the Little Snake River in northern Colorado.