What is hydraulic fracturing (fracking)?
Hydraulic fracturing, or fracking as it is commonly known, is a technique used to extract unconventional gases like shale gas, which are trapped underground in rocks with low permeability. As an unconventional gas, shale gas cannot flow easily through rocks, which is why horizontal drilling and fracturing are used for extraction.
Deep holes are drilled down into the shale rock, followed by horizontal drilling to access more of the gas reserves – as shale reserves are typically distributed horizontally rather than vertically.
Fracking fluids, containing a mix of sand, water and chemicals are then pumped at high pressure into the drilled holes, to open up fractures in the shale rock. This enables the trapped gas to flow through the fractures into collection wells, where it can then be piped away for commercial use.
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