Fracking - IELTS Reading Answers & Explanations

Read the article below and answer Questions 26–40.

Fracking

Fracking refers to a technique for extracting natural gas from shale deep within the earth. Fracking is shorthand for 'hydraulic fracturing' and refers to how shale rock is fractured apart by injecting a mixture of water and chemicals into it at very high pressure. Fracking for shale gas has become big business in the United States, where the search for energy is one of the country's main concerns. However, the procedure is controversial and has as many opponents as supporters.

Fracking is not a new technique. It was first used in the 1860s, and then used industrially in 1949. However, as the oil reserves in America decreased and energy sources from abroad became more expensive, gas trapped in shale became an attractive commercial proposition. Shale gas is natural gas, or methane, trapped in tiny pockets in shale rock formations. Shale rock is a form of mudstone formed between 252 and 66 million years ago. It is distinguishable because it is laminated (made up of thin layers) and fissile (it can be split into thin layers). For the energy industry, black shale is important because it is the source rock for many of the world's most important oil and gas reserves. Black shale gets its colour from organic matter that was deposited along with the mud from which the shale formed. As the mud was compressed and warmed within the earth, the organic material was transformed into oil and natural gas.

In order to extract shale gas, a shaft, or well, is drilled to over one mile deep into the earth and then horizontally into the shale rock. The vertical well is then encased in steel and/or cement. After that, water needs to be delivered to the site: this can be up to 200 tanker trucks. The water is mixed with sand and chemicals and a pumper truck injects this hydraulic fluid into the shaft at high pressure, causing the shale to crack, or fracture. The sand in the mixture keeps the cracks open, allowing gas to flow to the surface into storage tanks. The gas is then piped to users. Meanwhile, water recovered from the shaft is stored in open pits before being taken to a treatment plant for recycling and eventual reuse. After all the gas has been collected, the shaft is sealed off with concrete to make sure that the injected hydraulic fluid cannot escape into water supplies.

An estimated 250 billion cubic metres of natural gas were brought to the surface using this method in the US in 2013. Since the US government gave out licenses to companies, its carbon emissions have gone down. Indeed, fracking has quite a few things going for it. This is because natural gas is far cleaner to burn than oil or coal in power stations. Furthermore, the area occupied by a fracking well is much smaller than a conventional oil well. So the question is, if fracking is so simple, clean and efficient, why are people concerned about it?

The problem is in the method used to get the gas out. The chemicals in the hydraulic fluid are toxic, consisting of a mixture of lubricants, poisons to stop bacteria growing in the pipes, and hydrochloric acid to dissolve unwanted cement in the pipes. This chemical mix finds its way to the surface through accidents at well-heads, fluids flowing back to the surface and leaks in the system. There is also the economical and environmental cost of transporting and using water – between three and five million gallons of water are needed to fracture a seam.

Furthermore, some experts think that fracking may be linked to the occurrence of earthquakes – earthquakes of magnitude 2.7 on the Richter scale have been increasing near Oklahoma City, an area where gas has been extracted using the technique. But perhaps the most persuasive argument is that fracking simply prolongs our over-reliance on carbon-based fuels, when we should be moving to technologies that do not produce carbon emissions or that are not harmful to the environment, such as solar energy, wind or wave power. In effect, fracking does not deal with the real issue of how we can produce energy without harming the environment. However, many people think fracking could be America's bridge between the carbon-based energy systems of the past and a cleaner way of producing energy in the future.