Shale gas

Shale oil is an unconventional oil produced from oil shale rock fragments by pyrolysis, hydrogenation, or thermal dissolution. These processes convert the organic matter within the rock (kerogen) into synthetic oil and gas. The resulting oil can be used immediately as a fuel or upgraded to meet refinery feedstock specifications by adding hydrogen and removing impurities such as sulfur and nitrogen.

The refined products can be used for the same purposes as those derived from crude oil. Shale gas is natural gas that is found trapped within shale formations. Shale gas has become an increasingly important source of natural gas in the United States since the start of this century, and interest has spread to potential gas shales in the rest of the world.

In 2000 shale gas provided only 1% of U.S. natural gas production; by 2010 it was over 20% and the U.S. government's Energy Information Administration predicts that by 2035, 46% of the US natural gas supply will come from shale gas. China is estimated to have the world's largest shale gas reserves, according to Wikipedia.

Hydraulic fracturing (commonly called "fracking" or "hydrofracking") is a technique in which water, chemicals, andsand are pumped into the well to unlock the hydrocarbons trapped in shale formations by opening cracks (fractures) in the rock and allowing natural gas to flow from the shale into the well.

When used in conjunction with horizontal drilling, hydraulic fracturing enables gas producers to extract shale gas at reasonable cost. Without these techniques, natural gas does not flow to the well rapidly, and commercial quantities cannot be produced from shale, writes Geology.Com.

According to howstuffworks.com, the large amount of water needed to drill for shale can affect water availability for other uses, potentially impacting aquatic habitats. As a byproduct, fracking produces millions of gallons of wastewater. In the past, improperly treated wastewater has been found discharged into river basins, polluting the surrounding environment.

The potential also exists for fracking fluids to seep into aquifers if a well casing fails, posing a risk to ground water supplies. Drilling can disrupt lives, including heightened noise levels aided by the transportation of materials, construction of facilities and drilling process itself; deterioration of air quality with the rise of diesel fumes; and implications of potentially destroying communities' access to clean water etc.