Shale Gas is methane trapped underground in shale rock. The rock is very hard and must be cracked to free the gas, hence the need for ‘hydraulic fracturing’.
Hydraulic fracturing uses pressurised fluid to free trapped gas. Wells are drilled and the fracking fluid injected into them under high pressure to crack the rock. The fracking fluid consists of water, sand and a lot of toxic chemicals. Millions of gallons of water are used to frack a well. While the technique itself is not particularly new it has only come into widespread use during the explosion in shale gas extraction over the last few years in the US, which now has 400-600,000 fracking wells.
There are 12 licenses to frack for shale gas in the UK, five of which are held by Cuadrilla Resources in Lancashire. Cuadrilla is also beginning exploratory drilling in Balcombe, West Sussex, UK.
Academic articles about ‘fracking’, including studies into its safety, is available on the External Research page.