Natural gas before the natural gas can be transported. Natural gas extracted from oil wells is called casinghead gas (whether or not truly produced up the annulus and through a casinghead outlet) or associated gas. The natural gas industry is extracting an increasing quantity of gas from challenging resource types: sour gas, tight gas, shale gas, and coalbed methane. There is some disagreement on which country has the largest proven gas reserves. Sources that consider that Russia has by far the largest proven reserves include the US CIA (47 600 km³), the US Energy Information Administration (47 800 km³), and OPEC (48
Natural Gas Choice feet of natural gas, respectively. Ohio has had Natural Gas Choice since 1997. More than 40 percent of the state's residential natural gas customers were participating in choice programs as of September 2008. Several major Ohio natural gas utilities in Ohio have plans to exit the function of supplying natural gas to customers, leaving the gas supply function to independent natural gas supply companies. In 2007, Ohio had 3,273,791 residential, 272,548 commercial, and 6,865 industrial customers. They consumed approximately 300, 159, and 295 billion cubic feet of natural gas, respectively. Currently, Ohio has 35 natural gas suppliers certified to participate