WHAT IS FRACKING?
"Fracking" is short for hydraulic fracturing — a process oil and gas drilling companies use to fracture rock formations deep in the earth to extract shale oil, natural gas or coalbed gas deposits that may be unavailable with conventional drilling. Oil shale uses a different extraction process than shale oil. oil-shale-shale-oil-shale.pdf
IMPORTANT NOTE: The oil and gas industry defines fracking as the moment underground fractures are split. The public generally considers fracking as the entire drilling process.
Some estimate fracking has increased US recoverable reserves of oil by at least 30% and of gas by 90%.
Fracking wells can be vertical or horizontal. Horizontal fracking is newer technology where the well is drilled vertically, then the drill bit is turned to drill horizontally into the appropriate layer of rock. This short video shows the process.
When drilling begins, a 3 to 5 acre pad of land is cleared and access roads are built. This typically takes two weeks. Next, the setup of the rig and the drilling of the well take approximately two to three weeks per well with operations running 24 hours a day, seven days a week.
The well is then drilled, similar to how a water well is drilled. A mixture of water and chemicals, called drilling muds, are pumped into the hole to cool the drill bit. Steel pipe is then inserted and encased by cement. Two extra layers of pipe and concrete are installed from the surface to at least 50' below the lowest drinking water aquifer.
The drilling rig is then removed. A perforated pipe and explosives are lowered into the bottom of the well. When the explosives are detonated, holes are blasted through the perforated pipe into the solid pipe, cement and rock creating mini-earthquakes.
Pumps then inject large quantities of fracking fluid under extremely high pressure (approximately 13,500 pounds of pressure per square inch) to further fracture the rock at the bottom of the well. Fracking fluid is typically 99 percent water and sand (or other granulated material) and approximately one percent chemicals.
Two to seven million gallons of water and 5,000 to 6,700 gallons of chemicals are used per frack. The sand in the fracking fluid props open the cracks so the gas or oil can be extracted.
Fracking chemicals are linked to bone, liver and breast cancers, gastrointestinal, circulatory, respiratory, developmental as well as brain and nervous system disorders. Fracking chemicals have polluted drinking water and air in Colorado and other states.
Approximately half of the fracking fluid flows back out of the well. It's stored in pits, steel tanks or injected into deep underground wells. It may be reused to frack more wells.
Large tanks or pipelines may be installed to hold or transport the oil or gas. Literally tons of gases escape from the tanks into the atmosphere and are also burned off through a stack, which is called "flaring." Oil and gas companies don't find it profitable to trap these gases.
After wells are completed, the oil & gas company regularly returns to monitor and maintain the site. At some wellsites, large tanker trucks return to transport oil or remove naturally occurring water, called "produced water," which is separated from oil or natural gas during the production process.
Produced water contains fracking chemicals, highly concentrated salts, oil, grease, heavy metals and naturally occurring radioactive material (NORM). Filtering out toxins in produced water is beyond the capabilities of normal water treatment facilities.
Produced water in Colorado is generally placed in deep injection wells or evaporation pits. It's also released into surface water and sprayed on dirt roads to reduce dust -- with the surface owner's consent. COGCC has rules regulating the amount of acceptable toxins, though doesn't seem to regulate the amount of naturally occurring radioactive material.
A gas well will just have a pipeline leading to market and some hardware and maybe a tank for incidental fluid that comes out of the gas well during production.
An oil well will have a rocking pump jack that actually runs off and on during the many years of the production phase plus a large tank to store the oil until it can be regularly emptied into trucks and taken to market. These extra regular incursions onto the surface owner's land make having an oil well on a surface owner's land much more intrusive.
The depth of the vertical portion of the well varies depending on the geology of the area. In the Niobrara formation, it's approximately 5000 feet below groundwater aquifers. Piceance Basin natural gas is produced from the Williams Fork formation from approximately 4,500 to 10,500 feet below the surface.
The horizontal portion of the well can extend up to 5000 feet. Multiple wells are sometimes drilled from a single padsite. It is now common to have from eight to as many as 40 frac stages in a single well. A well can have a 20 to 40 year life. An average oil derrick is 110 feet tall. The cost to drill one well is $750,000 to $4 million.
At the end of the well's useful life, all of the un-cemented metal casing is to be pulled from the well and the empty down hole spaces filled with clay and cement.
El Paso Oil and Gas Summit, August 16, 2011 http://gomarsha.org/info/niobrara_oil_gas.html
What is produced water? http://www.netl.doe.gov/technologies/pwmis/intropw/index.html
Pumps and Systems Affirming Gasland Affirming_Gasland_Sept_2010.pdf
Affirming Gasland Affirming_Gasland_Sept_2010.pdf
The rush to drill for natural gas: a public health cautionary tale.
The Health Implications of Hydrofracking http://psehealthyenergy.net
How a Gas Well Is Drilled Down Into the Ground, and What Can Go Wrong
How fracking is harmful
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