Rajya Sabha TV In Depth Exploring Shale Oil
On August 1, 2018 Union Cabinet of India allowed simultaneous exploitation of unconventional hydrocarbon resources like coal-bed methane, shale and unconventional oil and natural gas. The decision is expected to boost domestic output and spur investments by different firms.
Diagram showing types of oil and gas wells
- A vertical well – Producing conventional oil and gas
- A vertical coalbed methane well
- A horizontal well producing from a shale formation
- A well producing from a tight sand formation
- Growing population and industrialisation are impacting every aspects of human life. The available resources on Earth are constantly decreasing due to the manner in which they are being exploited.
- Era of 1970s saw a revolution in crude oil production. Crude oil is a fossil fuel and it can be separated into various products (petrol, kerosene, diesel oil, fuel oil, lubricating oil, etc) by fractional distillation.
- The Gulf countries (Iraq, Saudi Arabia, Kuwait, etc in the neighbourhood of Persian Gulf), identified as energy centres, have provided the crude oil continuously over the past few decades.
- Five nations (Iran, Iraq, Kuwait, Saudi Arabia and Venezuela) formed The Organization of Petroleum Exporting Countries (OPEC) in 1960 in Baghdad. The multinational organization in 2018 has 15 members and accounts for 5% of world’s “proven” oil reserves. It has a major influence on global oil prices.
Map showing OPEC member nations marked in Blue colour
- But the capacity of these crude oil reserves is depleting as the resources are limited.
- This has led nations to find out new sources of energy. Shale Oil, which is being focussed by many countries like United States and India, is one such option. But its production is challenging and expensive.
- Unconventional oilis petroleum produced or extracted using techniques other than the conventional (oil well) method.
- Shale oil is an unconventional oil produced from oil shale rock fragments by pyrolysis, hydrogenation, or thermal dissolution. These processes produce synthetic oil and gas which can be used as a fuel or upgraded refinery feedstock
- Shale oil also refers to crude oil produced from shales of very low permeability formations, called as “tight oil”.
- Shale oil is formed by accumulation of mud, silt and organic wastes and, heat & pressure being applied on these biological wastes for millions of years.
- Shale is a fine sedimentary rock that contains high amount of organic matter which can produce a hydrocarbon. But the shale does not have permeability required to extract oil from it. So, processes are required to create fracturing on these rocks to get the gas to the surface.
- Shale oil extraction methods:
- Mined shale oils are transported to the processing plants, heated to 500OC, and oil comes out from these rocks.
- Situ technique: Oil shale is broken by explosion and Kerogen comes out like crude oil from these rocks.
Illustration of Hydraulic Fracturing
- India, third largest consumer of energy after China and USA, relies heavily on imports to service energy needs which drains fiscal resources due to volatile energy prices. So, efforts are required to increase domestic production of energy and thus, pushing towards unconventional oil sources along with renewable sources of energy are important for India.
- Many national and international organizations are estimating Shale Gas resources in India. As per ONGC estimates, it is 187.5 Trillion Cubic Feet (TCF) in Cambay, KG, Cauvery, Ganga and Assam basins. CMPDI has estimated 45.8 TCF of such reserves in the Gondwana basin.
- Table showing EIA Report, 2013 about estimated recoverable Shale Gas resources:
|Country||Trillion Cubic Feet|
Structural basins of shale (Source: US EIA)
USA is already extracting Shale Gas meeting about 20% of its domestic energy needs. India is at a very initial stage of estimating its available Shale Gas reserves. Its extraction is a big challenge and India needs to acquire complex technologies which involve fracturing, addition of required chemicals, applying pressure and horizontal drilling. Also, the hydraulic fracturing has potential to cause fugitive methane emissions, air and noise pollution, and water contamination which need to be taken care of to protect the environment. But, transition from extracting energy from crude oil and coal reserves to unconventional oil sources and renewables energies is required to serve its large energy needs.