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 prices above shale deposits compared to the rest of the US, highlighting that natural gas markets have become less integrated due to pipeline capacity constraints. Prices of natural gas for end-consumers vary greatly throughout Europe. One of the main objectives of the projected single EU energy market is a common pricing structure for gas products. A recent study suggests that the expansion of shale gas production in the U.S. has caused prices to drop relative to other countries, especially Europe and Asia, leaving natural gas in the U.S. cheaper by a factor of three. It is expected that the TTIP trade