Photo: karathepirate (Flickr)
What Is Hydraulic Fracturing?
Hydraulic fracturing is a drilling method used to obtain gas trapped in shale stone, the gas is known as shale gas.
Once a well has been drilled, “fracking fluid” (a mixture of water, sand, and chemicals) is pumped into the well.
The high pressure with which the fracking fluid is pumped into the well causes the shale rock to shatter. This allows shale gas to escape from the rock through millions of tiny cracks. This gas escapes into the pipeline where it can then be pumped to the surface.
Why Is Hydraulic Fracturing Controversial?
In 2004 the EPA declared fracking to be safe. But residents who live near natural gas wells that use fracking to access shale gas have complained of grease and debris in their drinking water. Initially, fracking fluids were blamed for the contamination.
However, recent studies on drinking water suggest that the real danger may be in methane contamination. Scientists testing well water have been looking for high levels of dangerous chemicals used in fracking fluid and radioactive materials from deep underground. What they have found instead are dangerously high levels of thermogenic methane or deep methane.
Since methane is a primary component of natural gas, it is released from shale rock when the rock is shattered by the hydraulic fracturing process. While the gasses should be trapped in the pipeline, the gasses can leak out of the metal casings that line the well hole. This leakage may be contaminating groundwater.
So What Is Thermogenic Methane And Is It Dangerous?
Methane is a gas that is made up of the chemical elements hydrogen and carbon and is an important component of natural gas. But did you know that there were different kinds of methane?
Thermogenic methane is methane found deep underground. It is the result of the break down of organic material by heat. Methane can also be formed when anaerobic bacteria digest organic material, but this type of methane, biogenic methane, is found at shallow depths and in our atmosphere as a greenhouse gas.
Unlike biogenic methane which is usually made up of only methane, thermogenic methane can contain methane with different carbon isotopes, ethane, and propane. While none of these substances are known to be toxic, they are all highly combustible.