Environment

In a first, natural gas hydrates discovered in the Indian Ocean

"This is the first discovery of its kind in the Indian Ocean that has the potential to be producible," USGS said in a statement.

A large natural gas discovery has been made in the Indian Ocean following a joint expedition by India and the U.S., opening up a new resource to meet energy needs.

India’s Oil Ministry and the US Geological Survey made the discovery of large, highly enriched accumulations of natural gas hydrate — an icy form of the fuel — in the Bay of Bengal.

“This is the first discovery of its kind in the Indian Ocean that has the potential to be producible,” the US agency said in a statement.

India had in September 2014 agreed to collaborate to explore gas hydrates potential in the country and identify sites for pilot production testing.

What are gas hydrates?

Natural gas hydrates are a naturally occurring, ice-like combination of natural gas and water found in oceans and polar regions. The amount of gas within the world’s gas hydrate accumulations is estimated to greatly exceed the volume of all known conventional gas resources.

They are considered as vast resources of natural gas and are known to occur in marine sediments on continental shelf margins. Gas hydrate resources in India are estimated at 1,894 trillion cubic meters and these deposits occur in Western, Eastern and Andaman offshore areas.

“Advances like the Bay of Bengal discovery will help unlock the global energy resource potential of gas hydrates as well as help define the technology needed to safely produce them,” said Walter Guidroz, USGS Energy Resources Program coordinator.

‘Most comprehensive gas hydrate field venture in the world to date’

This discovery is the result of the most comprehensive gas hydrate field venture in the world to date, made up of scientists from India, Japan and the United States.

The discovery follows an exploration of the region from March to July of last year.

“The scientists conducted ocean drilling, conventional sediment coring, pressure coring, downhole logging and analytical activities to assess the geologic occurrence, regional context and characteristics of gas hydrate deposits in the offshore of India,” the statement said.

'Significant technical challenges'

The U.S. agency said although it is possible to produce natural gas from gas hydrates, there are significant technical challenges, depending on the location and type of formation.

Previous studies have shown that gas hydrate at high concentrations in sand reservoirs is the type of occurrence that can be most easily produced with existing technologies.

The gas hydrates discovered are located in coarse-grained sand-rich depositional systems in the Krishna-Godavari Basin and is made up of a sand-rich, gas-hydrate-bearing fan and channel-levee gas hydrate prospects.

The next steps for research will involve production testing in these sand reservoirs to determine if natural gas production is practical and economic.

“The results from this expedition mark a critical step forward to understanding the energy resource potential of gas hydrates,” said USGS Senior Scientist Tim Collett, who participated in the expedition.

The discovery of several of the largest and most concentrated gas hydrate accumulations yet found in the world will yield the geologic and engineering data needed to better understand the geologic controls on the occurrence of gas hydrate in nature and to assess the technologies needed to safely produce gas hydrates, he said.

The international team of scientists was led by state-owned Oil and Natural Gas Corporation (ONGC), in cooperation with the USGS, the Japanese Drilling Company, and the Japan Agency for Marine-Earth Science and Technology.

In addition, USGS is working closely with the National Institute of Advanced Industrial Science and Technology, Japan on the analysis of pressure core samples collected from sand reservoirs with high gas hydrate concentrations.

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Printable version | Aug 1, 2020 10:13:14 PM | https://www.thehindu.com/sci-tech/energy-and-environment/In-a-first-natural-gas-hydrates-discovered-in-the-Indian-Ocean/article14509657.ece

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