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The Shale Gas Revolution (I)

Shale gas drilling rig in Pennsylvania

During the past few years, the development of new technology has allowed access to large reserves of natural gas. A revolution that is having a great impact on global energy markets has just begun. Have you ever heard about shale gas? This article presents some fundamental aspects of shale gas including the origins of shale gas industry and the prospects for the future.

What is shale gas?

Shale gas is natural gas trapped within shale formations. The main difference between shale gas and conventional natural gas is that shale gas is more difficult to extract. Conventional natural gas reservoirs are trapped within high permeability rocks. As a result, a conventional gas well is drilled and the gas flows in large quantities. On the contrary, due to the low permeability of shale formations, drilling is not enough to generate significant flow.

How is shale gas produced?

Shale gas extraction

Shale gas is extracted by horizontal drilling and hydraulic fracturing or “fracking”:

Horizontal drilling provides greater access to the gas trapped deep in the shale formation. First, a vertical well is drilled, and then the drill bit is turned to drill a horizontal well. The surface area in contact with the shale is substantially increased by drilling horizontal lengths up to 3000 metres.

Hydraulic fracturing or fracking is a technique in which water, chemicals and sand are pumped into the well to release the natural gas trapped in shale formations by opening fractures in the rock and allowing the gas to flow into the well.

Why is shale gas important? What would be the consequences of the shale gas revolution?

It is estimated that there are huge reserves of  shale gas in the world. It accounts for a considerable part of the global natural gas resources. Producing shale gas from most shale formations was not considered to be economically feasible just a few years ago. However, the development of the two key technologies involved in the shale gas extraction has enormously increased productivity and reduced costs.  If the estimations of the level of recoverable shale gas resources are accurate, shale gas could potentially provide abundant supplies of cheap natural gas.

An important point to consider is that combustion of natural gas emits significantly lower levels of pollutants than other fossil fuels such as oil or coal. Increasing the gas production and substituting oil and coal for gas will help to reduce greenhouse emissions and could provide a transition to a lower carbon economy.

On the other hand, there is growing concern about the negative environmental consequences of hydraulic fracturing. It produces large amounts of wastewater  which contains chemicals and that could contaminate the surroundings of the well, including land and aquifers. Moreover, there is a growing fear that shale gas may substitute not for other fossil fuels, but for renewable energy.

The revolution has already started. Is it likely to continue? Where?

The shale gas revolution is already happening in the United States. Shale gas rose from less than 1% of domestic gas production in 2000 to over 20% by 2010. The second part of the article presents how this revolution has been possible and what are the prospects for the future of shale gas in the United States. Another key question is discussed in the third part of the article: is it possible to replicate this revolution in Europe?

In WLT (Coming soon)| The Shale Gas Revolution (II)The Shale Gas Revolution (III)

Sources and More information| Are we entering a golden age of gas?The ‘Shale Gas Revolution’: Developments and ChangesShale gas fracking – Q&AWhat is shale gas and why is it important?

Picture| Shale gas drilling rig in PennsylvaniaShale Gas Extraction

 

Author Spotlight

Sergio de la Torre

Current Position:

Engineer at BPP-TECH. London, United Kingdom.

Associate Member of the Institution of Mechanical Engineers (IMechE).

Education:

Mechanical Engineer. Escuela Técnica Superior de Ingenieros, University of Sevilla, Spain.

MSc in Advanced Mechanical Engineering. Cranfield University, United Kingdom.

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