From UPSC perspective, the following things are important :
Prelims level : Shale Gas and Oil, Fracking processes
Mains level : Shale gas potential of India
Cairn Oil & Gas has announced that it is partnering US-based Halliburton to start shale exploration in the Lower Barmer Hill formation, Western Rajasthan.
What is Shale oil?
- Shale oil is an unconventional oil produced from oil shale rock fragments by pyrolysis, hydrogenation, or thermal dissolution.
- These processes convert the organic matter within the rock (kerogen) into synthetic oil and gas.
- The refined products can be used for the same purposes as those derived from crude oil.
How does it differ from conventional crude oil?
- The key difference between shale oil and conventional crude is that the former, also called ‘tight oil’, is found in smaller batches, and deeper than conventional crude deposits.
- Its extraction requires creation of fractures in oil and gas rich shale to release hydrocarbons through a process called hydraulic fracking.
What is fracking?
- Fracking is the process of drilling down into the earth before a high-pressure water mixture is directed at the rock to release the gas inside.
- Water, sand and chemicals are injected into the rock at high pressure which allows the gas to flow out to the head of the well.
- The process can be carried out vertically or, more commonly, by drilling horizontally to the rock layer, which can create new pathways to release gas or used to extend existing channels.
- The term fracking refers to how the rock is fractured apart by the high-pressure mixture.
Shale production in the world
- Russia and the US are among the largest shale oil producers in the world.
- With a surge in shale oil production in the US, it has played a key role in turning the country from an importer of crude to a net exporter in 2019.
Shale reserves in India
- As per the US EIA 2015 report, India has got technically recoverable shale gas of 96 trillion cubic feet.
- The recoverable reserves are identified in Cambay, Krishna – Godavari, Cauvery, Damodar Valley, Upper Assam, Pranahita – Godavari, Rajasthan and Vindhya Basins.
- The ONGC has drilled the first exploratory shale gas well in Jambusar near Vadodara, Gujarat, in Cambay basin during October 2013.
What are the prospects of shale oil exploration in India?
- Currently, there is no large-scale commercial production of shale oil and gas in India.
- Shale oil and gas exploration faces several challenges other than environmental concerns around massive water requirements for fracking and potential for ground water contamination.
- State-owned ONGC had, in 2013, started exploration and, by the end of FY21, assessed shale oil and gas potential in 25 nomination blocks.
- But it has reduced investments over the past few years after only getting limited success in shale exploration efforts.