In ancient seas, hydrocarbons of coal, crude oil and natural gas were deposited in sedimentary shale rock. Over the last century, the ‘conventional’ shallow reservoirs of these fossil fuels, are being depleted and now hydraulic fracking is used to extract deeper ‘unconventional’ natural gas deposits. Like the tar sands extraction, fracking is raising new ethical concerns.
What is fracking? A vertical well, reinforced with concrete, is drilled miles beneath the earth’s surface.