Q.1. Highlight the differences between ‘conventional’ and ‘unconventional’ hydrocarbons. What are the challenges faced by India in the extraction of unconventional hydrocarbons? – 250 words.
Q.2. Elucidate upon the nature and features of ‘shale gas’. How far has India been successful in its shale gas exploration and extraction efforts? – 150 words.
Q.3. Account for the effects of the process of ‘shale gas extraction’ on India’s ground water reserves. – 150 words.
Q.4. Shale gas exploration in India can prove to be beneficial for the energy requirements for the country but would prove to be a challenging process. Comment – 250 words.
Why in news recently: In August, 2018, the Central government approved a policy that allows private and government players to explore and exploit unconventional hydrocarbons (including shale gas) in contract areas that were primarily allocated for extracting conventional hydrocarbons.
Conventional vs. Unconventional hydrocarbons:
Conventional Oil and Gas are the resources obtained using traditional way to drill for raw natural gas, crude oil, and petroleum. In such process, after a well is drilled, oil and gas is extracted by the natural pressure from the wells and pumping operations. Over time, the production in the well may decrease. After the decrease in production, a conventional well will use an artificial lift or water and gas injections to help increase production. After production gets to a point where the profits of oil are not enough to cover expenses, the well will usually stop production.
If methods beyond an artificial lift or classic methods are used to increase production of oil and gas, then it would be classified at unconventional oil and gas (or unconventional hydrocarbons). Unconventional procurement is a method that allows to drill down, drill horizontally, and fracking (read more about fracking here) occurs. This allows oil and gas to be retrieved from sources that could not be retrieve with conventional methods of drilling.
What is shale gas and how is it extracted?
Shale gas refers to natural gas that is trapped within shale formations. Shales are fine-grained sedimentary rocks that can be rich sources of petroleum and natural gas.
Unlike conventional hydrocarbons that can be sponged out of permeable rocks easily, shale gas is trapped under low permeable rocks. Therefore, a mixture of ‘pressurised water, chemicals, and sand’ (shale fluid) is required to break low permeable rocks in order to unlock the shale gas reserves.
Source: The Hindu
Shale Gas Extraction and challenge to India’s freshwater reserves:
Huge volume of water required: The process to unlock the shale gas reserves requires around 5 to 9 million litres of water per extraction activity, posing a daunting challenge to India’s fresh water resources where both households and irrigation is hugely dependent on groundwater. Over a period of time, the usage of water dramatically increases for extracting the same amount of shale gas from a well. Such activities are likely to deplete water sources.
Groundwater contamination: Shale rocks are usually adjacent to rocks containing useable/ drinking water known as ‘aquifers’. While fracking, the shale fluid could possibly penetrate aquifers leading to methane poisoning of groundwater used for drinking and irrigational purposes.
Water cycle in a typical fracking process is different than other conventional hydrocarbon production activities. When shale fluid is injected underground at high pressure to fracture the rock, 5-50% (depending on the local geology) of the fluid returns to the surface, known as ‘flowback water’. Return flows continue as oil and gas is pumped from the well. The flowback water is usually methane-contaminated, and therefore it poses different recycling and leakage issues than usual wastewater.
- Environmental Impact Assessment (EIA) – There is a need to differentiate between conventional and unconventional hydrocarbons for the purposes of EIA so that different and more appropriate measures can be taken for the extraction of unconventional hydrocarbons which lead to depletion of more freshwater. No such differentiation exists currently. a sector-specific EIA manual on exploration and production of unconventional hydrocarbon resources is required.
- A consultative ‘water usage policy’, is required to prevent various issues including water stress, contamination of groundwater, and related health hazards.
Source: The Hindu
Shale gas as an energy resource for India:
No commercial discovery of shale gas reserves has been made in India as of July, 2018.
The government had announced policy guidelines for exploration and exploitation of shale gas and oil by national oil companies in October 2013 but the results in pursuance of this policy have not been encouraging. According to ONGC’s annual report of 2016-17, it has shelved various shale gas exploration phases due to limited success.
Shale gas exploration is important for India as India is looking to cut crude imports by 10 percent by 2022 by enhancing domestic production and tapping alternative sources.
Challenges to shale gas exploration in India:
- Non-availability of huge water resources needed for shale gas exploration. Most of our fresh water resources are heavily over-burdened.
- The challenge of land acquisition and displacement of people as large tracts of land is required for fracking. This is not an issue is countries like United States and Canada as these countries have less population density compared to India. Indian government may consider options like obtaining land on lease as is the case in the United States.
- The threat of contamination of groundwater and adverse affect on agricultural activities.
- Lower gas realizations by the companies engaged in exploration activities. The amount of gas found is not enough for commercial exploitation.
Some scientist have also suggested that large scale fracking activities can cause induced earthquakes however, more research is required on this contention.