The film Gasland purported to show how communities are adversely affected by hydraulic fracturing (also known as “fracing”). This film was full of inaccuracies and half-truths, and was apparently intended to incite opposition to fracing by masquerading as a “scientific” documentary. Environmentalists and politicians with a specific anti-energy agenda use films like this one to promote their own cynical goals. This campaign against a decades-old drilling practice continues despite numerous scientific studies and solid evidence disproving fracing’s naysayers.We can now add another study to that growing list. A effort by scientists and researchers at Durham University, Cardiff University (both in the UK) and the University of Tromsø (in Norway) has found that fracing at least 2,000 feet below an aquifer minimizes chances of water contamination in the United States. Their study was published at the end of April, 2012 in the journal Marine and Petroleum Geology. Of particular interest to Texans, it examined the Barnett and Eagle Ford Shales in Texas, as well as the Marcellus Shale in Pennsylvania, the Niobrara Shale in Colorado, and the Woodford Shale in Oklahoma.
One of the authors of the study, Richard Davies, said: “[T]he Earth has a number of safety mechanisms which stop natural hydraulic fractures from going on forever.” The study explains how hydraulic fractures can happen naturally, as rocks embedded with water deep underground get pressurized over millions of years. The liquid can cause the rock to crack, and the crack will continue until it hits another type of rock, and then it stops. What happens with man-induced hydraulic fracturing is very similar, as pressurized water is pumped into the rock to crack the shale and release the trapped natural gas. People worry that these cracks will go so far vertically as to connect the wells to the aquifers.
The study authors looked at thousands of natural and man-induced fractures all over the world. In particular, the authors looked at data from five natural gas shale reservoirs around the United States (those listed above). They found that the longest vertical crack was 2,000 feet long. That sounds like quite a long distance, but in reality these natural gas wells are usually fraced below 7,000 feet and the water aquifers generally exist above 1,000 feet. The study also points out that the chance of a crack being longer than 1,500 feet is less than one percent. The longest such crack anywhere in the world is 3,600 feet in Namibia. That crack apparently took billions of gallons of water and millions of years to reach that length. Even that fracture is not close enough to affect the aquifers at stake here-they are at least 6,000 feet away from the fractured area.
This is one of a handful of studies to take a scientific approach and could be a starting point for a scientific-based discussion on a minimum distance between fracing and aquifers. The research team and authors hope more data continues to become available and the study of these fractures can continue, but this is certainly a good starting point for a rational analysis. As a Texas oil and gas attorney, I strongly support these scientific advances and welcome new research on the topic. More science and less unfounded hysteria is definitely called for.
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