Methane hydrates represent a potential future energy resource. They contain an estimated 53% of all fossil fuel reserves on Earth in the form of methane gas trapped within crystalline structures of water under high pressure and low temperatures. While abundant in marine and Arctic sediments, recovering the methane requires techniques unlike conventional gas extraction due to methane hydrates' solid structure. Methods under investigation include thermal injection to raise temperatures above the dissociation point, depressurization to convert hydrates to gas and water, and slurry mining. Tapping this vast resource could help reduce greenhouse gas emissions compared to other fossil fuels if recovered safely without releasing methane into the atmosphere.

1. Methane Hydrates :
The future saviour of energy
PRESENTED BY,
JITENDRA KUMAR PRADHAN
DEPT. OF GEOTECHNICAL ENGINEERING
NIT JAMSHEDPUR

2. Background Study:
 Gas hydrates are crystalline solids that form from mixtures of water and
light natural gases such as CO2, methane, ethane, propane, butane. They
are of considerable interest for their potential as an energy resource and for
their potential role in global climate change.
 From an energy resource point of view, the enormous amounts of methane
hydrate under the ocean and beneath arctic permafrost represent an
estimated 53% of all fossil fuel (coal, oil, natural gas) reserves on earth,
about 10,000 gigatons.

3. Objective:
To study the exploration and recovery of this gas hydrates as it is not
amenable to conventional gas and oil recovery techniques.

4. Methodology :
 Gas hydrates are crystalline molecular complexes formed by the physical combination of
water and low molecular weight gases at high P and low T and having general formula
Mn(H2O)p.
 Clathrates are the lattice like structures in which molecules of one substance are
completely enclosed within the crystal structure of another.
 Methane hydrates, which form structure I gas hydrate, store immense amount of methane
and occur in abundance in marine and Arctic sediments. One unit volume of methane
hydrates can contain over 160 volumes of gas and less than one unit of water at standard
conditions.
 Methane is a less carbon-intensive fuel than coal or oil. Methane from hydrates produces
only half as much carbon dioxide as coal per unit of combustion products.
2Coal(CH) + 2
1
2
O2 → 2CO2 + H2O
CH4 + 2O2 → CO2 + 2H2O

5. ( Unit cell of a gas hydrate of structure II )
( Methane
hydrate sample )
( Burning of the
solid methane
hydrate sample )

6. Map of world Gas hydrates:

7. Results:
Various methods for the recovery of the gas hydrates are :
 Thermal injection:
Heated at constant P until the system temp. increases the dissociation temp.
 Depressurization:
Pressure reduces to the adjacent zone of hydrates; at dissociation pressure gas
hydrates convert into gas and water.
 Slurry mining
 Replacement of Methane hydrate with Carbon dioxide hydrate (recent
technique)

8. Conclusion:
 Methane is an excellent fuel as it produces less carbon dioxide per mole
than any other fossil fuel. Thus, it can reduce the amount of
anthropogenic emissions of carbon dioxide gas, which may cause the
greenhouse effect.
 The amount of fossil fuel in hydrate form is approximately twice as
large as in all other fossil fuels combined.
As per its abundance in the earth it can be treated as a potentially new
source of energy.

9. Comments:
Methane hydrate is present abundantly as solid form in earth. If they are
recovered in well manner then its will be the saviour of the energy sources; as
day by day the decay of natural resources (fossil fuels) are going
exponentially. But any disputes during the recovery process like leakage of
methane gas into the atmosphere may affect the aquatic life and also can be a
potential threat to the environment.