Monday, July 19, 2010

Indian Sedimentary Basins And Shale Gas

Over the last few months, several articles and papers have emphasized the potential role shale gas will play in India's hunt for energy. Shale gas is natural gas trapped in fine grained sediment.

Update May 18 2011: [ See post India Basin-Wise Shale Gas Estimates for estimates of shale gas from various Indian sedimentary basins.] 

These articles did not have any graphics so I am putting up a map of Indian sedimentary basins and a graphic depicting shale gas geological reservoirs.

Indian Sedimentary Basins

 Source: Geotimes

The basins of interest in terms of shale gas potential are the mostly marine Mesozoic and Cenozoic basins in Rajasthan and Gujarath and the Cenozoic basins of Assam. The Gondwana basins of central and eastern India are continental interior rift basins and are coal rich and have associated coal bed methane which if tapped could also play an important role in India's energy mix.

Shale Gas Geological Reservoirs

Unlike gas reservoirs in coarser materials like sands, natural gas in shale is trapped in micro pores which may not be connected to each other i.e. they have low permeability and the gas is quite difficult to extract.

India's conventional natural gas reserves are growing with new discoveries mostly along the east coast Krishna Godavari offshore basins. Early estimates of these gas resources if proved correct may more than double in terms of energy equivalence India's proven reserves of about 5.6 billion barrels of oil. Unconventional resources like shale gas have the potential of adding substantially  more to these resources. Currently natural gas makes up a small portion of India's energy consumption pie (see fig on left) and the chance to move towards a cleaner emissions profile by substantially displacing coal in power generation (coal makes up about 70% of electricity generation) and eventually as fuel for transport makes these unconventional sources a critical energy resource of the future.

I don't know how much shale gas resources India has because there has not been a systematic evaluation of shale gas. India's current energy policy prohibits exploitation of shale gas and coal-bed methane. The sooner that policy changes the better for energy starved India.  

[Update Sept 3:] As a reader pointed out in the comments there is recent movement from the government on the exploitation of shale gas and coal bed methane. See this article. A policy on shale gas is likely to be out by next year, while the government has already auctioned of several blocks for exploration of CBM from various basins.

Still, there is one aspect of exploiting these resources that has not been touched upon by any of the articles I have come across and that is the environmental costs of extracting shale gas. Since this gas is locked up in impermeable layers one of the common methods of extracting it is by hydraulic fracturing of the rock. This involves injecting the shale with fluids and gels mixed with particulates like sand to keep the induced fractures open and enable migration of the gas along open fractures.

A new film "Gasland" discussed on Science Friday last month looks at some of the problems of hydraulic fracturing or "fracking" of the Marcellus shale that underlies large parts of Pennsylvania, New York and Ohio and West Virginia.  Chemicals used in the injecting fluid has been reported to contaminate groundwater in Pennsylvania. At least according to the film, the energy companies have been less than forthright about the chemical composition of the injecting fluids which the film claims includes carcinogens and neurotoxins.

All this should send warning signals about the way and means by which India goes about exploiting these shale gas resources.  Groundwater is as important a resource for India's economic development as is natural gas. Almost all drinking water needs in rural areas are met by groundwater. A significant majority, about 2/3, of arable area in India is irrigated by groundwater.  Contamination of large portions of the overlying aquifer will be nothing short of a catastrophe for farmers who have no other water supply but groundwater.

The exploitation of coal bed methane offers another avenue for social conflict. The Gondwana basins which are coal rich are forested regions and home to many tribal communities. There has been a long history in India of the government and private mineral companies riding roughshod over tribal rights. The current violent insurgency that is taking place along tribal regions of Chattisgarh, Maharashtra and Jharkhand has its roots in the rampant exploitation and callous indifference shown by the state and private companies towards tribal communities.

So, shale gas and coal bed methane offer a significantly large energy source but also open up the possibility of more environmental and social disruption.

Update May 18 2011: For latest estimates of shale gas see - India Basin-Wise Shale Gas Estimates.


  1. There is no prohibition for exploration of CBM & Shale gas in India. New energy policy of Govt of India encourages exploration and exploitation of non-conventional energy resources including Coal Bed Methane, shale gas and gas hydrate. Large number of CBM blocks have already been alloted by Director General Hydrocarbon (DGH), Govt. Of India through two rounds of international bidding.Few companies have already started production of CBM.DGH has already started contacting relevent agencies for assesing Shale gas potential in India.

  2. Mr. Suvrat, I saw Gasland recently and also came across articles in newspapers about India seriously thinking of exploiting shale gas. Do you think it is wise to exploit all resources that we humans can lay our hands on? Can we not let some things in nature be. As humans do we have to 'consume' everything. In the name of development we are eating into the earths natural wealth. What legacy are we leaving behind for our future generations. It is obvious that the path followed by the developed nations have not been wise, still why do we insist on following the 'ways of the west' (pardon the expression) as the best solutions to our problems.

  3. Swapan- thanks for the update. The source I relied on, Mr.Aiyar's article in the Times indicated that the government has yet to give a green signal. But you are right. I did some reading and there is movement on both shale gas and CBM. I have posted an update.

  4. i am updating THE status in matters of allotment of CBM blocks , up to Dec.2010. by Director General Hydrocarbon (DGH) of Govt. India has alloted 34 blocks out of proposed 70 blocks initialy, in total 4 (FOUR) rounds. the main Awardees are ONGC,OIL,GAIL,RIL,RNIL
    ON 26.01.2011 ONGC has struck a vast area of shale gas AT A DEPTH OF 1770 meters.THE Gas reserved spred over an area of1250 to 1300 the total gas reserves range between600 and2000 trilion cubic ft. is in damodar basin in the eastern region of Raniganj caol field . this is the 3rd. country in the world after USA And CANADA making it the focalpointin India's persuit of Green Energy.
    Mining Eng.of Total CBM Solutions India Pvt. Lt.

  5. Hello Deb- thanks for the update;

    I think the numbers you have put out 600 -2000 trillion cubic feet are Gas in Place estimates i.e total gas content of prospective formations and not proven reserves. extractable resource will be a fraction of this amount. These amounts are for India, not just the Damodar basin...

  6. I am really very ecstatic that we have found shale gas resources in India.Now without wasting any time we have to tap this potential to run our economy on cleaner and cheaper fuel.Just surprised by hearing the news recently that US had overtaken Russia to be be the largest producer of natural gas in the world.I feel shale gas production in US has a lot to do for this achievement.Remember China has already started shale gas auction process as they too have huge reserves we should'nt be late in this race.

  7. Shale gas resources seem to also be abundant within Marcellus and this is probably why companies buy Marcellus Shale Mineral Rights.

  8. India has enough resources. Is it a challenge to mix these with people and other resources to deliver an end-product that adds value to the people of India. This is quite different from letting US companies explore, produce and sell the resources under the lowest cost requirements.
    The issues (blackouts and brownouts) that arise are capacity issues rather than commodity challenges.
    Using the capacity challenges to speed up FDI by US and german companies is an attempt to mislead the public opinion.

  9. i think india should mainly focus on R&D technology in order to explore and exploit gas hydrates because india has huge potential of gas hydrates prognosticated to be 1895 TCM struck in rich deposits of fractured shales in the KG offshore area.

  10. Anjan-- thanks for that perspective..can you please give me a link to the source of the gas hydrate estimates in KG offshore? ..