Unconventional gas resources in the U.S.A.

Unconventional gas accounts for more than 40% of U.S. domestic gas production and more than 10% of world output. The amount of resources available is still uncertain and estimates vary to a large degree. In this paper, unconventional gas resources within the United States will be examined. This paper will take a brief look at all types of unconventional gas resources (there have been 6 identified) but will concentrate on shale gas and coal-bed methane, as they are the resources receiving the most attention. This paper will also delve into the technology in unconventional gas production and exploration, including recent innovations in the industry. Finally, environmental concerns unique to unconventional gas production will be addressed. Natural gas refers to naturally occurring hydrocarbons found trapped underground. It occurs as mixtures of hydrocarbons of various molecular weights (methane, butane, etc.) and was formed millions of years ago from fossilized organic matter. Natural gas can be used as a cleaner burning alternative to other fossil fuels for power generation. It produces half the amount of carbon dioxide as coal and roughly 25 percent less carbon dioxide than gasoline. Consequently, it is becoming more popular in today's environmentally conscious world. Worldwide demand is expected to increase at twice the rate of oil until at least 2030. Interest in natural gas is at an all-time high in the United States. Only recently have we learned about the vast unconventional resources that exist within our borders. The implications for reduced dependence on foreign sources of gas are promising for the future of this country. There may be sufficient resources within the United States to allow this energy source to thrive for many years to come. Natural gas can be divided into two categories: 1) Conventional gas which is found in reservoirs where the gas has been trapped by a layer of rock. Usually conventional gas refers to that which exists on top of crude oil reservoirs. Conventional gas is relatively easy to extract because once a well is drilled, the gas will naturally flow to the surface. 2) Unconventional gas which is referred to gas trapped in formations where it cannot easily flow such as in shale formations; or, gas that is tightly attached to the surface of the surrounding rock such as in coal-bed seams. Unconventional gas is more difficult to extract because it often requires fracturing the rock formation to allow the gas to accumulate in sufficient quantities and flow out of the well. There are six types of unconventional gas resources: shale gas, coal-bed methane, deep gas, tight gas, geopressurized zones, and methane hydrates. Each of these unconventional gas resources within the United States will be examined with a focus on their development and the unique challenges facing them. [ABSTRACT FROM AUTHOR]