Fuel fight: a look at the pros and cons controversial new drilling technique.
hydraulic fracturing Hydraulic fracturing is a method used to create fractures that extend from a borehole into rock formations, which are typically maintained by a proppant. The method is informally called fracing. to tap into our own country's fuel sources.
Like all extraction techniques, hydraulic fracturing, or fracking, has its pros and cons. So what is fracking, and why is it such a hot topic?
THE ENERGY DEBATE
Although researchers are working on ways to generate more energy from renewable sources like the sun, wind, and water, most of America's energy still comes from fossil fuels--oil, natural gas, and coal. New technologies like fracking are allowing oil and gas companies to access fossil fuel fossil fuel: see energy, sources of; fuel.
Any of a class of materials of biologic origin occurring within the Earth's crust that can be used as a source of energy. Fossil fuels include coal, petroleum, and natural gas. sources that used to be out of reach.
The U.S. imports nearly half of all the oil it uses. Canada, Mexico, and Venezuela supply most of this foreign oil. The rest comes from around the world, including politically unstable countries like Iraq.
In a time of rising gas prices and instability in the Middle East, there is general agreement that the U.S. should become more energy-independent. How we do that is a matter of debate.
The U.S. has vast oil and natural-gas reserves trapped in hard-to-reach places, but tapping into them could harm the environment.
FUEL FROM STONE
Deep underground, source-reservoir rocks hold oil and natural gas inside their pores the way sponges hold water. Traditionally, oil and gas drillers have tapped into rocks with high permeability, so oil and gas flow easily into wells and to the surface. "As soon as you tap it, it's like sticking a straw into a juice box For the record label, see .
The Juice Box is a low cost Mattel multimedia player with a small screen (2.7" / 240x160px). It was marketed as a portable media player for kids. The player only played a proprietary cartridge format. that's being squeezed," says Ronald Bishop Ronald Bishop may refer to:
Established in 1889 as a state normal school with the sole mission of training teachers, the College at Oneonta was a founding member of the State University of New York system in 1948. .
Fracking, however, taps into reservoirs in which oil and gas are locked in shale--a rock with low permeability. "That oil and gas don't flow fast and it doesn't flow far," says Jennifer Miskimins, a petroleum engineer at the Colorado School of Mines.
To get at that oil and gas, workers bore a deep vertical shaft, and then drill horizontally through the shale. Then they crack the shale by injecting millions of gallons of water, chemicals, and sand under high pressure into the well (see diagram, right). Oil and gas flow through the cracks and up the well. The U.S. has many shale formations, with the largest, called Marcellus Shale, stretching beneath much of the Northeast.
Hydraulic fracturing has created a natural-gas boom. Because of its potential to generate jobs, it's a hot topic in this year's presidential race. But it's also raised concern that leaks from well pipes could contaminate con·tam·i·nate
1. To make impure or unclean by contact or mixture.
2. To expose to or permeate with radioactivity.
con·tam·i·nant n. drinking water drinking water
supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. . Another problem is disposing of used fracturing fluid. "We now are generating much larger volumes over much shorter time frames than anybody seemed to be prepared for," says Bishop. Many water-treatment plants aren't equipped to handle fracturing fluids. Some companies reuse the fluid, but eventually it becomes too dirty. A common disposal method--injecting the wastewater back underground--is thought to have triggered a string of earthquakes in Ohio last year. Scientists suspect that the injected water lubricated lu·bri·cate
v. lu·bri·cat·ed, lu·bri·cat·ing, lu·bri·cates
1. To apply a lubricant to.
2. To make slippery or smooth.
To act as a lubricant. an existing fault, allowing the rocks to slide.
Engineers are researching better solutions, and the Environmental Protection Agency is investigating fracking's effects on drinking water. Fracking is on hold in New York New York, state, United States
New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of State until more is understood about its environmental impacts. Other states are also considering regulations.
When it comes to energy, there's no simple solution. Alternative sources have downsides--but so does foreign oil. As Miskimins says, "The unconventionals have opened up a whole new world of self-sufficiency."
HOW HYDRAULIC FRACTURING WORKS
Hydraulic fracturing, also called fracking, is a way to extract natural gas from rock. The idea is simple but controversial: A well is drilled deep underground to reach natural gas trapped in shale deposits. A series of small explosions are used to crack the rock, then chemicals and water are pumped down to widen the fissures so the gas can escape and be captured aboveground.
(1) A drill bit on the end of a drill pipe bores a hole into the ground.
(2) A wide pipe is inserted into the hole.
(3) Cement is pumped around the pipe to prevent gas leaks from contaminating underground water sources.
(4) PERFORATING AND FRACTURING
The horizontal portion of the well is drilled. A smaller-diameter pipe, called a production casing, is inserted.
A perforating gun containing explosive charges is inserted into the casing. It blasts small holes in the shale.
Water, sand, and lubricants are pumped into the well under high pressure, forcing the shale to fracture, or break up.
(5) Gas flows up the well to the surface.
* Diagram is schematic, not to scale.