What is Shale Gas?
Natural gas (mainly methane) is generally classified under two heads:
- Conventional gas
- Unconventional gas.
Most of the natural gas that is produced globally comes under the category of conventional gas where, after drilling in a sedimentary basin that is rich in gas, the gas migrates through porous rocks into reservoirs and flows freely to the surface where it is collected, treated, and then piped to various users. Shale gas is an “unconventional” source of methane, like coal-bed gas (in coal seams), tight gas (trapped in rock formations) and gas hydrates (off shore frozen methane).
Shale gas is located in rocks of very low permeability and does not easily flow. Therefore, the technique for recovery of shale gas is quite different from that of conventional gas. The technology implied is a complex one and is just out of development phase. The main steps involved are:
- Shale rock is sometimes found 3,000 meters below the surface. Therefore, after deep vertical drilling, there are techniques to drill horizontally for considerable distances in various directions to extract the gas-rich shale.
- A mixture of water, chemicals, and sand is then injected into the well at very high pressures (8,000 psi) to create a number of fissures in the rock to release the gas. The process of using water for breaking up the rock is known as “hydro-fracturing” or “fracking”.
- The chemicals help in water and gas flow and tiny particles of sand enter the fissures to keep them open and allow the gas to flow to the surface. This injection has to be done several times over the life of the well.
Advantages of the shale gas technology
- Using gas as a fuel in itself is a big advantage because it is cheaper to generate electricity fromgas, and the process releases up to 50% less carbon dioxide than does coal.
- Shale gas can serve as a useful substituent for the fast depleting natural gas reserves.
- With the advances in exploration technology, large reserves have been discovered in USA, Europe and India till date. This paves way for the disconcentration of energy resources from the middle-east and the resulting political turmoil that engulfs the region.
- It shows promising potential for substituting future fuelling needs, especially for industries dependent on gas like power petrochemicals and fertilizers.
Disadvantages of the shale gas technology
- Gas in itself poses certain problems as a fuel including high cost of transportation and storage, liquefaction etc. Also gas prices vary around the globe regionally and it has no global price. (On a separate note, India and Japan, the two leading importers of LNG in Asia are working together to formulate a Uniform Gas pricing policy)
- Shale gas, in particular, involves more complex extraction technology for optimal exploitation of shale gas/oil which requires horizontal and multilateral wells and multistage hydraulic fracturing treatments and still awaits certain environmental clearances.
- High risk of investment as the technology is still infant and yet to show any significant returns.
- It poses threat to underground water resources and aquifiers from hydro-fracturing and fracturing fluid disposal.
- The water after hydraulic fracturing is flowed back to the surface and may have high content of Total Dissolved Solids (TDS) and other contaminants
What the world is doing?
The US is the technology leader in the exploration and extraction of shale gas. There are 34 states in the US, which have vast deposits of rocks rich in shale gas. Production of the gas has added about 20 per cent to domestic gas availability and over 20,000 wells have been drilled. From being an importer of LNG, the country is now self-sufficient and there are plans to export gas from the very terminals that were built for imports. It is being called The North American shale gas revolution.
Europe has not had the same success in exploiting shale gas as the US for several reasons. In the US, resources under the land belong to the land owner who is happy to allow drilling and get paid by the gas companies, whereas in Europe—as also in India— these resources belong to the government. Also, important tax benefits are given to companies in the US to drill and produce shale gas. In Europe, the geology of shale rock is different from that of the US and it is more likely to be found in places that are more densely populated. The NIMBY effect (“Not in My Back Yard”) is much more prevalent in Europe than in the US. France, Bulgaria, Luxembourg, the Czech Republic, and the Netherlands have either banned or put a moratorium on shale gas exploration.
What India is doing?
The Ministry of Petroleum and Natural Gas (MoPNG) has identified six basins as potentially shale gas bearing. These are Cambay, Assam-Arakan, Gondwana, Krishna-Godavari, Kaveri, and the Indo-Gangetic plain. In a study conducted by the United States Geological Survey (USGS), recoverable resources of 6.1 tcf(trillion cubic feet) have been estimated in 3 out of 26 sedimentary basins. According to the Oil and Natural Gas Corporation (ONGC), there are about 34 tcf of shale gas in the Damodar basin alone (compared to India’s total conventional gas reserves of 47 tcf) of which 8 tcf are recoverable.
The Government of India had also put out in 2012,a draft policy for the exploration and exploitation of shale gas, inviting suggestions from the general public, stakeholders, environmentalists, etc.
Indian Scenario: Roadblocks and how to move forward
As has been already mentioned above, India has a significant amount of recoverable and prospective estimates of shale gas reserves which overshadow the conventional gas reserves. These could totally change the game in the energy deficit crisis that India is facing today. Yet, we have a long way to go in identifying shale gas rich basins and acquiring the necessary technology and experience to extract shale gas.
Let us have an objective look at the major concerns which need to be addressed before banking upon such an alluring prospect:
- The number of wells to be drilled for shale gas far exceeds the number of wells required in the case of conventional gas and the land area required is a minimum of 80 to 160 acres. India has already been facing several cases regarding various projects running down because of inadequate land acquisition policies.
- The most egregious is the issue of water requirements. Shale gas procurement may require large volume of water 3-4 million gallons per well depending upon the well type and shale characteristics.These concerns need a second look in a country such as ours which is already a water-stressed country and is fast approaching the scarcity benchmark of 1,000 m3 per capita. In the next 12-15 years, the consumption of water will increase by 50% while the supply will increase by only 5 to 10%.
- The water after hydraulic fracturing is flowed back to the surface and may have high content of Total Dissolved Solids (TDS) and other contaminants. The possibility of contamination of aquifier (both surface and subsurface) from hydro-fracturing and fracturing fluid disposal is also persistent.
These are some of the concerns which have been raised since the prospect of shale gas as a potential fuel dawned upon India. But any new technology comes with a baggage of criticisms which are necessary in their own sense. However, it is evident that India needs to tap this energy source since its natural gas market continues to see a deficit. In 2012-13 natural gas consumption in India is expected to stand at 104.4 bcm against its production of 40.7 bcm.
- India needs to build strong service and infrastructure capabilities, along with a favourable regulatory regime.
- A framework policy which while addressing environmental and social concerns, can also promote exploration and production activities.
- A mandatory rain-water harvesting provision in the exploration area which trivializes the extent to which the water which will be utilized in extraction.
- As far as possible, river, rain or non-potable water should be used for fracking and appropriate investment should be made in technologies minimizing the water use and reuse and recycle of water.
- Adequate land acquisition policies and proper implementation of LARR Bill, 2013
Some Interesting Facts:
Interestingly, Reliance Industries Ltd (RIL) has made big investments (US$ 3.5 billion) in the largest unconventional gas field in the US which is one of the largest worldwide, with estimated net recoverable resources of 318 trillion cubic feet (tcf) (In comparison, the resources in RIL’s own D6 fields in the KG Basin were estimated to hold around 3.4 tcf in November 2012, dropping from 10.3 tcf in December 2006.(you know why!!)). Oil India Limited (OIL), Indian Oil Corporation (IOC), and GAIL India Limited have also made investments in shale gas production in the US.
The other interesting contribution to shale gas development in the US is the export of guar gum from India, which helps in improving the viscosity and flow of water in the fracking process. The gum is extracted from guar ki phalli, grown mainly by farmers in arid lands in Rajasthan and Haryana. Earlier, guar gum was used mainly as an additive in ice creams and sauces, but with the serendipitous discovery of its use in shale gas extraction, its production has risen enormously, earning almost US$ 5 billion during the period from April 2012 to January 2013.
Also, Nicaragua has expressed interest to invite propositions from Indian firms for a $40 billion project to connect the Pacific and the Atlantic Ocean by a mammoth canal. Its primary objective is to facilitate the passage of ultra large tankers carrying shale gas from US into the Asian and African markets which cannot be accommodated through the Panama Canal.