Krishna-Godavari basin: Search on for more gas hydrates located in sand zones

Syed Akbar
Hyderabad:: The Krishna-Godavari basin contains fairly large
quantities of gas hydrates that could serve the future energy needs of
the country. Teams of scientists and explorers from several research
organisations are now busy scouting the shallow waters of the Bay of
Bengal in the KG basin to pinpoint gas hydrates trapped in sand zones.

Gas hydrate is a type of natural gas, mostly methane, and hailed as
the fuel of the future, when naturally occurring oil and gas is
exhausted or turns low on reserves. Gas hydrates were discovered in
the clay zones of the KG basin a few years ago. The present search is,
however, for location of gas hydrates in sand zones. Exploitation of
gas hydrates in clay zones is a difficult and uneconomical task as of
now thanks to lack of technology, while it is relatively easier to tap
gas hydrates from sand zones.

Buoyed by the successful find of gas hydrates in clay zones, teams
from the National Institute of Oceanography, the National Geophysical
Research Institute, the Directorate-General of Hydrocarbons and the
Oil and Natural Gas Commission among others are now searching for gas
hydrates trapped in sand zones in the KG basin.

“Gas hydrate has been found in clay zone of the Krishna-Godavari basin
(site No. 10 NGHP). It is as much as 120 metres thick. The thickness
is, however, not uniform. A few metres away from the site, the
thickness was between 40 mtrs and 60 mtrs. More exploration need to be
done to estimate the exact quantity of gas hydrate in the KG basin.
But the present find is significant as one cubic metre of gas hydrate
yields nearly 164 cubic metres of pure methane gas and about 0.8 cubic
metres of fresh water. Since there’s no viable technology to utilise
gas hydrates in clay zones, scientists are looking for gas hydrates in
sandy zones,” said Dr T Ramprasad, senior geophysicist from the
National Institute of Oceanography, Goa.

He said India and US had through a joint programme demonstrated the
technology to tap gas hydrates in land. However, in the case of KG
basin the gas hydrates are trapped in water. “In future we will be
able to tap the gas hydrates trapped in clay zones in the ocean,” Dr
Ramprasad hoped, adding that India need to switch over to
non-conventional energy fuels like methane trapped in gas hydrate
deposit.

Though India has about 0.4 per cent of the world’s proven reserves of
crude oil and natural gas, the demand in the country is as high as 2.8
per cent of the global consumption. In this backdrop, the search for
more gas hydrate deposits in sand zones in the KG basin gains
significance.