I talk to a lot of people in the course of my job as Director of HR and IR/PR at my company. I love to explain the method of mining – in-situ recovery (ISR) – that my company does because it is technologically fascinating, environmentally friendly, and economical. Often when I’m explaining ISR, people wrinkle their noses – and sometimes sneer – at me and say that it sounds just like fracking. I have to explain to them its not but, as a big supporter of fracking (aka hydraulic fracturing), I consider it important to explain what fracking is when I get this reaction.
I’ve already written about ISR uranium mining here. Today, I’m going to explore fracking.
Fracking has actually been around since 1949 and estimates are that over one million wells have been hydraulically fractured since. The method is used primarily to extract natural gas and shale oil from shale formations that used to be economically impossible to develop. With the recent technology advances in horizontal drilling, fracking has made these formations economical and as started an oil and gas boom in the United States.
Today, fracking is being used in the Bakken Shale deposit in North Dakota and Montana, the Barnett Shale deposit in Texas, and the Marcellus Shale deposit in the northeast.
Here is how fracking works. A well is drilled straight down until a “kickoff” point is reached where the drillers start to arc off horizontally to reach the shale layer. The well is typically about 7,000 to 8,000 ft deep from the surface to the shale layer and is cased with cement to protect the water table which is at about 800 to 1,000 ft deep. Once the shale layer is reached, the horizontal drilling continues for about 3,000 to 4,000 ft. Production casing is inserted into the horizontal borehole and then surrounded by cement. Charges are then detonated inside a perforating gun that blasts small holes into the shale. At this point, a pressurized mixture of water, sand (proppant), and chemicals are pumped into the well at about 4000 gallons per minute. This action generates many small fissures in the shale which frees the trapped gas and oil allowing it to flow out of the well and to the surface where it piped to the market.
Its important to note that the water table is no more than 1,000 feet down and the fracking is occurring 7,000 to 8,000 feet down. I doubt the fissures are reaching the water table 6,000 to 7,000 feet away. I mention this because those who oppose fracking claim that the method contaminates drinking water by leaching the chemicals and methane into the water table.