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Fracking earthquakes...

There has been a lot of talk in the national news about fracking, and we aren't talking about "special time" for “Battle Star Galactica” geeks. Hydraulic fracturing (or fracking for short) is a process used in oil or gas drilling where water and other components are injected deep underground to fracture subterranian formations allowing natural gas to come to the surface. According to researchers from the U.S. Geological Survey, there has been a significant increase in earthquakes in the middle of the United States compared to previous years.
 
The U.S. Geological Survey reports that for the three decades until the year 2000, seismic events across the middle of the nation averaged only 21 per year. Then in 2009 events jumps to 50 per year, in 2010 they increased to 87 per year, and then in 2011 there were 134 reported seismic events. Some are pointing to fracking as the reason for the increase in seismic events across the middle of the United States, which historically has very few seismic events. However, scientists believe that these seismic events are perhaps more related to wastewater disposal underground than fracking.
 
“Our scientists cite a series of examples for which an uptick in seismic activity is observed in areas where the disposal of wastewater through deep-well injection increased significantly,” David Hayes, the deputy secretary of the U.S. Department of Interior, said in a blog post yesterday, describing research by scientists at the U.S. Geological Survey.
 
According to Haynes, the seismic events across the middle United States are generally "very small" and rarely cause damage. He also notes that not all instances of fracking or wastewater injection cause seismic issues. Fracking injects contents such as water and some chemicals, into the shale formations within the earth. The point is to break apart underground formations and free natural gas trapped there.

Hayes added, "We also find that there is no evidence to suggest that hydraulic fracturing itself is the cause of the increased rate of earthquakes."
 
Bloomberg reports that much of that wastewater comes back to the surface and has to be disposed of. This is where the difference between hydraulically fractured wells and disposal injection wells comes into play. Disposal injection is taking the wastewater created from fracking and injecting it back underground.
 
Daniel Whitten, a spokesman for the America’s Natural Gas Alliance, told Bloomberg, "[There is] a difference between disposal injection wells and hydraulically fractured wells. There are over 140,000 disposal wells in America, with only a handful potentially linked to seismic activity."
 
However, he did point out that the industry is committed to monitoring the issue and working with authorities when there's a concern about seismic activity in an area. 

Source: Bloomberg



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RE: Good thing?
By mars2k on 4/13/2012 1:52:31 PM , Rating: 2
Fracking creates fissures across the rock strata and the methane trapped flows out. There is no way to control where the fissures open. If they propagate where the water table is then what happens to the water?
There a lots of places where oil wells were drilled. These wells were sunk thousands of feet deep and many crossed though water bearing rock strata. The oil depleted and the wells get capped but the holes are still there and the pipe casing for the well has long since rusted out. Residual oil, gas, and salt water now contaminate the fresh underground water.
So if you had a choice between methane or the only source of water available which would you choose?
We keep making long term decisions for short term solutions. Once the ground water is ruined it stays ruined even if the gas is depleted


RE: Good thing?
By Solandri on 4/13/2012 4:23:32 PM , Rating: 5
quote:
The oil depleted and the wells get capped but the holes are still there and the pipe casing for the well has long since rusted out. Residual oil, gas, and salt water now contaminate the fresh underground water.

While I agree with you that contamination from the fracking itself is an issue, you have a lot to learn about oil wells. You do not just sink a pipe into a ground.

An oil well is probably best described as a straw within a straw. The outer straw is made of metal casing held in place against the surrounding rock by cement. The inner straw is a metal pipe. When drilling, you send the bore and lubricants down the inner straw, and the dirt and muck come up the outer straw (the lubricant is cleaned and recycled because it's a helluva lot more expensive than oil). Later, oil comes up the outer straw. Only the very bottom part of the well lacks this cement and metal outer straw.
http://en.wikipedia.org/wiki/Casing_%28borehole%29

Permanently "capping" a depleted oil well doesn't mean you just put a lid on it. It means you remove the inner straw, and fill the outer straw with mud and cement plugs (or sometimes cement all the way). The hole is not there anymore. The plug is not metal with a hole as you imply. It is cement - metal - cement with no hole.

The pressure differentials make it way too dangerous to leave any hole in a well you don't plan to use later. A well is like the weight of miles of dirt sitting atop a waterbed, pressurizing the water. If you drill a hole through that dirt and poke a hole in the bed, the water will squirt up through your hole. And you get the Deepwater Horizon blowout we had a couple years ago. They had oil coming up both the inner and outer straws, meaning they could not send heavy mud and fluid down the inner straw to repressurize the oil and stop its flow.


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