Krishna-Godavari (KG) Basin

The methane hydrate deposit in this region is a rich supply of methane, a natural gas, that will assure adequate supplies. Methane is an environmentally friendly and cost-effective fuel. One cubic metre of methane hydrate is expected to contain 160-180 cubic metres of methane. Even the most conservative estimate of methane found in KG Basin methane hydrates is double that of all existing fossil fuel reserves globally.

Fire Ice

Clathrate of methane

Methane clathrate (CH45.5H2O) or (8CH446H2O), also known as methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, but rather gas hydrate, is a solid clathrate compound (more specifically, a clathrate hydrate) wherein a large amount of methane is trapped within such a crystal structure of water, forming a solid that resembles ice.

Originally assumed to only exist in the Solar System’s furthest reaches, where temperatures are cold and water ice is abundant, substantial amounts of methane clathrate have been discovered beneath sediments on Earth’s ocean bottoms. 

Methanogenic diversity in the KG basin

Researchers at the Agharkar Research Agency (ARI), an independent institute of the Department of Science and Technology of the Government of India, discovered that the methane hydrate deposits in the Krishna-Godavari (KG) basin are of biogenic origin, according to a recent study. 

The research was carried out as part of the DST-SERB young scientist project “Elucidating the community structure of methanogenic archaea in methane hydrate.” When hydrogen-bonded water and methane gas collide at high pressures and low temperatures in the ocean, methane hydrate is created.

Points to Remember

Methane generated by the metabolic activity of living organisms is known as biogenic methane. The methanogens that formed the biogenic methane locked as methane hydrate, which can be a substantial source of energy, have been discovered by the study team.

Microorganisms that create methane as a metabolic by-product under hypoxic (low oxygen) circumstances are known as methanogens.

The ARI team discovered that Methanosarcina is the most common genus in the KG basin, followed by Methanoculleus and Methanobacterium.

Hydrated Methane

A methane molecule is encircled by a cage of interlocking water molecules in methane hydrate, a crystalline solid.

Methane hydrate is a type of “ice” that only forms spontaneously in underground deposits with favourable temperature and pressure conditions.

Difficult to handle: Remove the ice from this temperature/pressure environment, and it becomes unstable. As a result, studying and working with methane hydrate deposits is challenging.

Because the pressure is dropped and the temperature rises when they are brought to the surface, they cannot be drilled and cored for examination like other subterranean materials.

As a result, the ice melts and the methane escapes.

Methane hydrate is also known by several other names. Methane clathrate, hydromethane, methane ice, fire ice, natural gas hydrate, and gas hydrate are examples of these.

Other hydrocarbon hydrates are found in minor concentrations in most methane hydrate deposits. Propane hydrate and ethane hydrate are two examples.

The study’s significance

Methane is an environmentally friendly and cost-effective fuel.

One cubic metre of methane hydrate is expected to contain 160-180 cubic metres of methane.

In comparison to the Andaman and Mahanadi basins, this study indicated the most methanogenic variety in the KG basin, which is one of the main reasons to believe it is the most severe source of biogenic methane.

Basin of the Krishna-Godavari

The Krishna-Godavari Basin is a huge deltaic plain produced by two big east coast rivers, the Krishna and Godavari, in the state of Andhra Pradesh, and the adjacent portions of the Bay of Bengal into which these rivers discharge their water.

The KG Basin is a vast continental margin basin located on India’s east coast.

Its land size is 15000 square kilometres.

The offshore section encompasses a total area of 25,000 square kilometres and extends up to a 1000 metre isobath.

The sediments in the basin are around 5 km thick, with multiple cycles of deposition dating from the Late Carboniferous to the Pleistocene.

Upland plains, coastal plains, recent flood plains, and delta plains are the basin’s principal geomorphological units.

The D-6 block is noted for having India’s largest natural gas reserves. ONGC made the first gas finding in 1983.

The Olive Ridley Sea Turtle makes its home in the basin (IUCN Status: Vulnerable).

Metabolic byproduct in hypoxic conditions

Microorganisms known as methanogens create methane as a metabolic byproduct in hypoxic environments. They belong to the Archaea domain and are prokaryotic.

Euryarchaeota in the archaeal phylum includes all known methanogens. Methanogens are found in wetlands, where they cause marsh gas, and in the digestive systems of animals such as ruminants and many people, where they cause ruminant belching and human flatulence.

The biological generation of methane, also known as methanogenesis, in marine sediments is usually limited to areas where sulphates are depleted, which is usually below the top layers. 

Furthermore, colonies of methanogenic archaea are critical in the treatment of anaerobic wastewater. 

Others are extremophiles, which may be found in extreme conditions like hot springs and submerged hydrothermal vents, as well as kilometres below the surface in the “solid” rock of Earth’s crust.

Conclusion

This region’s methane hydrate deposit is a rich source of methane, a natural gas, that will provide enough supplies. Methane is a cost-effective and ecologically beneficial fuel. Methane hydrate is estimated to contain 160-180 cubic metres of methane per cubic metre. Even the most cautious estimate of methane discovered in KG Basin methane hydrates exceeds all known world fossil fuel reserves.