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Hydraulic fracturing: fracking

Fracking: Old technology, new controversy

24 October 2011

The economic transformation taking place in South Texas is the stuff of fantasy, but the drilling method that has made it possible – hydraulic fracturing, or ‘fracking’ – is immensely controversial. And now it is in the UK. Roz Wrottesley reports


‘Cuadrilla Resources is a UK company… focused on bringing together leading unconventional oil and gas explorers, developers and technologists to unlock untapped unconventional resource plays in selected parts of Europe. In the United Kingdom we are the first company to explore unconventional energy sources. We are currently working on two sites at the Bowland Shale near Blackpool in Lancashire, and we have permission to explore a further four nearby.’
Cuadrilla Resources website

That uncomfortable word ‘unconventional’ was explained when Cuadrilla Resources CEO Mark Miller appeared before the House of Commons Parliamentary Energy and Climate Change Committee’s Shale Gas enquiry in March: “We’re not really using unconventional technology,” he said. “Shale gas exploration techniques, including hydraulic fracture, are conventional and have been used across the oil and gas industry for many decades. It is the resources that are unconventional.”

Indeed, hydraulic fracturing was introduced in the US by the energy production company Halliburton in 1947, but has expanded dramatically recently thanks to new horizontal drilling methods. With oil and gas production in the US falling and hydrocarbons still the world’s leading source of energy, the company argues that fracking is essential, as well as being one of the most effective and safe methods available of stimulating production. In fact, according to both Halliburton and the Interstate Oil and Gas Compact Commission in the US, 90% of oil and gas sites in the US make use of fracking technology to improve production. By one estimate, shale gas will account for up to half the natural gas production in North America by 2020.

The process

Where oil- and gas-bearing rock formations are relatively impermeable and slow to release their reserves, large volumes of fluid (around 95% water, plus sand and chemicals) are pumped underground under pressure to fracture the reservoir rock and allow the oil or gas to escape at a much faster rate. While the sheer volume of liquid causes the fractures, the process is facilitated by the chemicals (usually including hydrochloric acid), which help to dissolve the rock and make it more porous. The sand – or in some cases, ceramic beads – is deposited in the cracks to keep them open. Other substances may be added to the mix to aid the flow of fluid, including gelling agents and nitrogen gas.

Much of the fracking fluid is removed to allow the flow of oil of gas, but some (as much as 20% and 40% by some estimates) remains trapped. The oil companies claim it cannot reach the surface or pollute water supplies, but opponents of the technology argue otherwise, claiming that the process is the likely culprit in a number of reported cases of deterioration in the quantity or quality of the water supply in the US.

As exploration for oil- and gas-bearing shale rock formations moves from the US to Canada, Australia, parts of Asia, South Africa, the UK and other European countries, such as the Netherlands and Poland, Greenpeace is a leading opponent of the technology and provides inspiration to local opposition groups. The environmental group lists its main concerns as pollution of underground water sources, depletion of water resources, a carbon footprint from fracking that exceeds that of coal, landscape degradation and noise pollution.

Such arguments are having great resonance in some areas: in the Canadian city of Quebec in June, 3,000 protesters joined a march against shale gas drilling; in South Africa, sustained public opposition to plans to drill for gas in the semi-arid Karoo area were put on hold in April while the true ecological consequences are explored; in France, the National Assembly voted to ban the practice in May and, at the time of writing, it remained to be seen whether the Senate would agree, making France the first country in the world to impose an outright ban.

Tremors in Lancashire

In the UK, the shale gas ‘find’ off the Lancashire coast near Blackpool – at a site known as Preese Hall 1 – in the middle of last year was hailed as the first significant find in Europe, with potential to make an important contribution to the UK’s gas resources.

Green Party objectors and a report funded by the The Co-operative Group and published in January called for a moratorium on fracking operations until the environmental impact had been fully assessed. The report, produced by the University of Manchester’s Tyndall Centre for Climate Change Research, referred to a temporary ban on fracking in New York State (now lifted) prompted by suspicions that shale gas extraction carried a risk of ground and surface-water contamination. It also suggested that exploiting unconventional gas and oil resources would only delay the development and adoption of renewable alternatives.

However, the Department of Energy and Climate Change (DECC) remains broadly supportive of shale gas exploration, and the Energy and Climate Change Committee’s enquiry earlier in the year dismissed fears about the safety of fracking and, in particular, the risk it might pose to underground water supplies.

Fracking duly began in March, but two minor earth tremors in the area in April and May have prompted Cuadrilla Resources to cease operations voluntarily while experts investigate whether they were caused by the drilling.

At the time, Brian Baptie of the British Geological Survey told The Independent newspaper, “It is well-established that drilling like this can trigger small earthquakes. We had a couple of instruments close to the site and they show that both events were close to the site and at a shallow depth,” he said.

“The timing of these two events, in conjunction with the ongoing fracking at the site, suggests that they may be related.”

An operations status report published by Cuadrilla on 28 June said the company was taking the ‘prudent and responsible’ course of suspending operations until the company could supply DECC with a detailed geomechanical report establishing whether or not there was a link between the tremors and the fracking operations.

The company went on to say:

“The intensity of the tremors is well below anything that could be realistically considered as an earthquake with any meaningful or tangible local impact. The tremors have not led to any recorded structural damage or physical injury and the British Geological Survey describes these tremors in a statement as ‘pretty insignificant even by UK standards’.

“Contrary to some misreporting in the media, drilling operations are not affected, as no link has been suggested between drilling and seismic activity. Therefore the Grange Hill site is still active. Plans to drill at a site near Becconsall, between Preston and Southport, are progressing and public consultation is already under way with the local community and officials. A community consultation event attended by over 100 local people took place on 6 June.

“Cuadrilla is investing in more seismic monitoring equipment for the operations, to enhance the coverage already supplied by the British Geological Survey, which was installed after the 1 April event at Cuadrilla’s request. Cuadrilla remains certain that its operations are completely safe for people, property and the environment.”

The report is also available as an Executive summary.

Further information

Related competencies include: T001, T049, T055