In areas where that is not an option, it may be treated and reused or processed by a wastewater treatment facility and then discharged to surface water. Hydraulic fracturing is a technique used in "unconventional" gas production.
This is often because the gas is highly dispersed in the rock, rather than occurring in a concentrated underground location. Extracting unconventional gas is relatively new. Coalbed methane production began in the s; shale gas extraction is even more recent. The main enabling technologies, hydraulic fracturing and horizontal drilling, have opened up new areas for oil and gas development, with particular focus on natural gas reservoirs such as shale, coalbed and tight sands.
Shale Gas Extraction. Shale rock formations have become an important source of natural gas in the United States. Shale gas is present in many locations in the contiguous United States, including some areas where oil or gas production has never occurred before. Production of Coalbed Methane.
Coalbed methane CBM was first extracted from coal mines as a safety measure to reduce the explosion hazard posed by methane gas in the mines. Today the methane is captured and used as a source of energy. This is natural gas trapped in formations that are generally not permeable and porous.
They are trapped in reservoirs with permeability in the Milli Darcy range. In addition to the above three major types of unconventional gas resources, Coal-to-Gas produced by destructive distillation of coal and methane hydrates formed from mixture of water and natural gas in permafrost and deep marine sediments are often referred to as unconventional gas resource.
As mentioned earlier, unconventional gas resources are found in unusual geological locations and therefore require special extraction technologies. Notwithstanding this, the combination of two independent technologies of horizontal drilling and hydraulic fracturing cracking of rock by pumping in highly pressurized liquid made their exploitation possible. They are more than 4 kilometres below the surface, making it really difficult to produce them.
Shale gas has the same composition as natural gas. Every shale gas is a natural gas, the difference between the types of gases are the locations of the reservoirs.
Natural gas can be found in big amounts, while shale gas is trapped inside the microcracks of a rock. They can also be liquefied and stored efficiently.
Read more about liquefied natural gas. Natural gas is transported through pipelines or shipped in a liquified state. There are four types of natural gas extraction methods:.
Because of the tough layer of shale, shale gas can only be extracted with hydraulic fracturing or even acidizing. With high-pressure streams of water, sand, and chemicals it breaks up the formation of rocks. Acidizing happens most of the time with fracking. This way, the acid is dissolving the rocks that may be on the way of the shale gas, so the gas can go upwards into the streamline.
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