As oil and gas company Cuadrilla has been given the green light on 12 October to begin fracking immediately at a site in Preston New Road, Lancashire, many people will be wondering what the shale gas extraction process involves. Dan Robinson looks at the question - what is fracking?

Fracking rig

A fracking rig

It’s one of the most contentious issues among environmental campaigners and isn’t going away anytime soon – but what is fracking?

The complex engineering process for extracting shale gas is long established in countries like the United States but has been banned by countries including Ireland, France, Germany and the Netherlands.

It had also been neglected by the UK until now.

A number of oil and gas companies have been given licences by the government to explore for the fossil fuel deep underground, and now the country’s first frack appears to be imminent.

UK firm Cuadrilla was granted permission by the High Court today (12 October) to begin fracking at a site in Preston New Road, within the parish of Westby-with-Plumptons, after a last-ditch attempt to stop it was turned down.

Other counties bracing themselves for fracking – short for hydraulic fracturing – include North Yorkshire, South Yorkshire, Nottinghamshire, Derbyshire, Lincolnshire and Cheshire.

What is fracking, how fracking works
A diagram of how fracking works

Cuadrilla isn’t the only business taking firm steps towards shale gas extraction, with the likes of Ineos Shale, IGas and Osprey Oil and Gas among those holding similar exploration licences.

Fracking supporters say it will create a new industry that brings investment, jobs and energy assets to the UK, but environmentalists heavily oppose it due to concerns it could contaminate the water supply, cause earthquakes and destroy natural landscapes.

For the wider public, though, the unconventional drilling method being pursued in England is a complex engineering process that many don’t fully understand.

Here, we break down what fracking involves.

A drilling rig used for fracking in the USA

What is fracking? Explaining hydraulic fracturing

Fracking is a type of drilling technique that involves fracturing rock deep underground in order to extract shale gas – a natural fuel that is trapped within shale formations.

Energy firms will drill at first vertically down into the ground at between 6,000ft and 10,000ft, and then horizontally by more than a mile.

Hairline cracks with a radius of about 300ft are then opened up in the rock by pumping in water, sand and some chemicals, allowing gas to flow into the pipes.


What is fracking? Permission is needed to begin shale gas extraction

Oil and gas companies that hope to explore for shale gas must first obtain a Petroleum Exploration and Development Licence (PEDL) from the government’s Oil and Gas Authority.

This allows a company to pursue a range of oil and gas exploration activities, subject to necessary drilling and development consents, and planning permission from the local authority.

Once a company has negotiated the lease of land on which it wishes to frack, it must seek planning permission for pre-fracking research.

This includes seismic surveys, which provide 3D images of the underground resources, and a vertical drilling to obtain examples of the rock.

Should the firm decide there are sufficient shale gas reserves, it must seek further planning permission.


How a fracking site looks

The three stages of shale gas extraction

There are three stages to fracking, with the final phase lasting decades.

Drilling contractors will typically create up to 30 wells over a five-week period, using a 180ft sub-structure similar in appearance to those used on offshore oil rigs.

A fracking team will then take over the site for about two weeks to open up the fissures in the rock and collect the shale gas through pipes.

Once this work has been completed, a production unit will create a small well pad of pumps feeding into green containers to extract the gas over many years.

The containers are connected to the national grid supply system for the lifespan of the well.


The dangers of fracking

Opponents believe fracking carries a significant risk of contamination with hazardous chemicals, not least the water supply – where there have been numerous complaints of tap water being discoloured, causing illnesses and even flammable in the US.

Fracking rig

There are those who argue it contributes to global climate change and destabilises underground rock formations to induce earthquakes.

They also question the economic sustainability of fracking, saying it would require thousands of wells that would transform the countryside, where natural landscapes would be destroyed and organic farmers would be under threat.


What is fracking? Benefits of shale gas

Fracking companies contend that water supplies should not be affected because the piping structure should protect gas from leaking into the aquifer, the underground layer of rock from which groundwater can be extracted using a water well.

Pipes have up to seven layers, each reinforced by concrete, as they pass through the aquifer and are reduced to one layer of steel at about 3km deep.

Supporters also claim that fracking has helped to revolutionise the energy industry in the USA and that the UK could become a net exporter of gas, rather than spending money exporting from other countries.

They also believe the industry could create tens of thousands of jobs and attract billions in investment in communities that were once dependent on mining.

A well pad in Pennsylvania in the final phase of the fracking process

What is fracking? The UK government’s position

Believing shale gas has the potential to provide the UK with greater energy security, economic growth and jobs, the government is encouraging its exploration to determine the potential.

It cites research by the British Geological Survey, which says there are 1,300 trillion cubic feet of gas reserves in northern England, and has handed out PEDLs to numerous energy firms to carry out surveys.

In terms of why gas is needed, it cites how it is used in every aspect of our lives – for heating homes, transport and in industry – and how natural gas accounted for just over a third of the UK’s energy usage in 2015.

But the government has also pledged to have strong regulations to ensure safety on site and prevent any negative environmental impact.

In May, it announced plans to accelerate fracking development by changing the planning process so decisions could be made “faster and fairer”.

It also proposed a £1.6m shale support fund for local authorities and a consultation on whether exploration wells could be drilled without seeking planning permission.