Shale gas reserve in India, source of clean energy
THE HANS INDIA |
Dec 02,2018 , 03:42 AM IST
Shale gas has abundant reserves around the world, which may be sufficient to meet the demand of clean energy for many years to come. Shale gas is found in unconventional reservoirs typically trapped in shale rock, having low permeability, originally deposited as clay and silt.
This makes it more difficult and more expensive to extract because of high upfront costs. Shale gas is generally found at 2000 to 5000 meters below the earth’s surface unlike conventional natural gas – trapped in sandstone rock having high permeability and can be easily assessed to be produced by traditional vertical drilling, found at 1500 meters. The technique used for shale gas production requires first drilling a vertical well to the targeted rock followed by horizontal drilling exposing the well to more of producing shale.
This process is called Hydraulic Fracturing or Fracking, in which water, chemicals and sand are pumped at high pressure into the well to unlock the gas trapped in shale rocks by opening cracks or fractures in the rock and allowing gas to flow from shale into the well and onto the surface. Shale gas is cleaner burning than coal and crude oil. The combustion of shale gas emits significantly lower levels of key pollutants including carbon dioxide, nitrogen oxide and sulphur dioxide than the combustion of coal and oil.
Looking at the reserves of shale gas, the Energy Information Administration (EIA) Agency of the US, Department of Energy, has listed eleven countries where in technically recoverable shale gas reserves are there namely Argentina, Algeria, Australia, Brazil, Canada, China, India, Mexico, Russia, South Africa and US. Out of these, the US, Canada and China have shown capabilities in shale gas production.
The United States of America
United States is the pioneer country in shale gas production. Technically recoverable shale gas in the US is 665 trillion cubic feet. The first gas well was dug during 1821, near Fredonia, New York. The rapid rise in shale gas production in the US has led to renewed interest in unconventional natural gas sources globally. Till 2000, there has been almost nil shale gas production in the United States and it reached 34 percent of all the natural gas production in 2011 and EIA report of 2015 has projected 50 percent of shale gas production of the total natural gas production by 2040. Further it may be supplemented by other unconventional natural gas sources viz Coal Bed Methane and Tight Gas accounting for 70 percent of total natural gas supply from unconventional gas sources by 2040 in the US.
The US EIA has estimated that 573 TCF of Canada shale gas is technically recoverable. Canada has got short history of development and production of shale gas, but its full potential of resources is not yet known. The Federal and Provincial governments are still in the process of developing a comprehensive and standardized approach in evaluating Canada’s unconventional resources. In 2012, shale gas accounted for 15 percent of the total natural gas production in Canada. A recent report by the Canadian National Energy Board estimates that shale gas will account 28 percent of Canada’s total natural gas production by 2035. Despite this, Canada’s shale gas production is still in nascent stages compared to the US.
The US EIA estimated China’s recoverable shale gas reserves as 1115 TCF, the largest of any country in the world. China is turning to natural gas as a way to decrease pollution created by burning coal. Shale gas in China is seen as a way to reduce dependence of imported gas. During 2017, China shale gas production was 9 billion cubic meter and is likely to increase to 17 bcm by 2020.
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 Oil and Natural Gas Corporation has drilled the first exploratory shale gas well in Jambusar near Vadodara, Gujarat, in Cambay basin during October 2013. It is estimated that from this basin around 20 TCF shale gas is recoverable.
In addition to shale gas, India has got reserves of other unconventional natural gases like Coal Bed Methane, Coal Mine Methane, and Tight Gas which are in the different stages of development/production. The country has 9.9 trillion cubic feet of recoverable Coal Bed Methane (CBM). The CBM is extracted from virgin coal mines. At present CBM is produced from four blocks - Jharia in Jharkhand, Raniganj East and South in West Bengal and Sohagpur West in Madhya Pradesh.
It is estimated that India may produce about 5.5 million standard cubic meters of CBM by the end of this year which could be about 5 percent of the total natural gas production in the country. At present Coal Mine Methane is not trapped and is blown out of coal mines. Tight Gas reservoirs in Eocene formations in Gujarat and Northeast India have been discovered. As per the study by the US, Oil Field Services Company, total reserves of tight gas at Cambay amount to 0.55 TCF, production of which at present is not economically viable but with the new technologies in place these reserves may be trapped in future.
In production of shale gas, all countries have more or less same challenges like availability of land, availability of sufficient water and treatment of flowback water, seismic threat and methane emissions etc. The requirement of water, sometimes, increases substantially in the successive production years as experienced in the US. This may affect requirement of water for drinking and agriculture etc all around the area. In Fracking process one fourth to one half of fluid mixture comes back to the surface as wastewater/flowback water, which contains high levels of dissolved solids and sometimes naturally occurring radioactive materials.
This waste water requires treatment at the surface. Another challenge is the availability of land. The Indian government can authorise shale gas exploitation by granting licenses at its level but disincentive to the occupier of the land becomes a stumbling block. Nevertheless, the vast population cover and agriculture pursuit in Indian condition may pose a challenge in shale gas production.
India’s opportunities and prospects
It is necessary that the country should, initially, have base line water data about stock and its characteristics for all the exploration/exploitation sites, which may require a lot of capacity building in manpower resources at states and districts level.
The Union government should allow all major companies - ONGC, OIL, GAIL & RIL etc to explore shale gas on pilot project basis in different basins so as to understand the properties and behaviour of different shale formations in different Indian basins. The Centre needs to issue regulations so that the State governments may enforce these regulations as land and water being state issues. India’s shale gas production will reduce coal consumption and will help to mitigate emission of Green House Gases.
Some observers suggest that potential of shale gas is enormous, and this energy can become a ‘game changer’ in the global energy market where conventional supplies are already on decline and demand of energy is on rise.
Looking at the impact on Indian economy with respect to import dependence on crude oil and natural gas – India’s oil import dependence was more than 81 percent of its total consumption requirement in 2016-17 which rose to about 83 percent in 2017-18 and may rise in the current year according to the Oil Ministry’s Petroleum Planning & Analysis Cell.
Therefore, in this scenario where India’s energy needs are growing and with the advent of new technologies, this is the right time to explore and exploit shale gas and other unconventional natural gases on equal priority to crude oil duly having proper plan for redressal of challenges.
(Tej Singh Kardam - The writer is retired IFS officer and former Deputy Director, Institute of Reservoir Studies, Oil and Natural
Gas Commission, Ahmedabad)