Shale gas is the natural gas that is found trapped between shale formations. Shale is a fine-grained sedimentary rock that is often a good source of petroleum and natural gas. Sedimentary rocks are found by addition of sediments subjected to pressure from above deposited material over ages. Shale, limestone and sandstone rocks are common examples of sedimentary rocks.
The permeability of shale rocks is often lower, which means they have less pores and so the flow of gas is hampered through the rock, this makes production of gas a costly affair. Although, it has been known that shale gas could serve as an energy source for a very long time, the technology to recover gas was not an economic proposition until recently.
Shale gas has over the years has become a significant source of natural gas in the United States and confirmed the belief that a net importer energy country can become energy surplus driven largely by energy from shale. In India, as per GAIL website, “GAIL is preparing itself to participate actively in the Shale Gas Bidding Round which is expected to be launched by Government of India. GAIL is a member of Multi Organisation Team (MOT) along with DGH (Directorate General of Hydrocarbons), ONGC and Oil India Limited (OIL).”1
Shale gas was very difficult to recover earlier but advancement in fracking technology has made it easier and economically viable option. Usually a combination of drilling and fracking is used for extraction. Chemically-treated water at high pressure is injected into the ground, this results in the gas being released. Fracking is just a part of the entire process and not the complete method of extraction in itself which also include construction of a well, use of hydraulics for injecting water and finally, production of the gas.
India for its part has a draft shale gas exploration policy seeks to correct the imbalance of energy demand and supply in the country.
“Demand of natural gas in India was 179 MMSCMD during the year 2010-11 and it is projected to be 473 MMSCMD in 2016-171. As against this, the total production of natural gas from indigenous sources was 146 MMSCMD during the year 2010-112.”
The Shale gas policy recognises the environmental impacts of such explorations and recommends a series of measures such as mandatory rain water harvesting, use of river or non-potable water for drilling purposes, provision of multi-well pad based drilling etc.
Environmentalists have expressed concerns about the water pollution issue surrounding shale gas exploration. There is also fear that drinking water sources can be polluted from the leakages from the well.
Another bigger area of concern for a water stressed country like India is the large supply of water that shale gas exploration requires. When you don’t have enough water to drink, is it a wise idea to make use of a technology where you just pump in water to extract gas? Can a water stressed country like India afford to waste precious water?
Given the uncertainty over the pollution caused by the chemically treated water injected into the earth that has the potential to cause ground water pollution, nations like France and Bulgaria3 have banned it.4
“USGS scientists have found that at some locations the increase in seismicity coincides with the injection of wastewater in deep disposal wells5.” Each frack cycle consumes about 3 to 5 million gallons of water6.
In conclusion, it can be said that India is no doubt an energy deficit country and needs all the power that it can derive but at the same time it is also water stressed country and is steadily marching towards becoming a water scare country. Therefore, unless some more technological advancements can limit the use of water r do away with the need of wasting water for deriving shale gas, it doesn’t make much sense to pursue it. Furthermore, all the available shale gas deposits in the country need to be identified first.