July 26, 2017 (LBO) – The U.S. Geological Survey (USGS) says it has assisted the Government of India in the discovery of large, highly enriched accumulations of natural gas hydrate in the Bay of Bengal.
“Advances like the Bay of Bengal discovery will help unlock the global energy resource potential of gas hydrates as well help define the technology needed to safely produce them,” said Walter Guidroz, USGS Energy Resources Program coordinator.
Natural gas hydrates are a naturally occurring, ice-like combination of natural gas and water found in the world’s 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.
The research is the result of a partnership between the Government of India, the Government of Japan, and U.S. scientists, USGS said in a statement.
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.
This research expedition, called the Indian National Gas Hydrate Program Expedition 02, is the second joint exploration for gas hydrate potential in the Indian Ocean. The first expedition, also a partnership between scientists from India and the United States, discovered gas hydrate accumulations, but in formations that are currently unlikely to be producible.
The development of Natural Gas industry in India started in 1960s with discovery of gas fields in Assam and Gujarat.
After discovery of South Basin fields by ONGC in 1970s, Natural Gas assumed importance. Later, discoveries were made in Gujarat, KG basin, Cauvery basin, Tripura, Assam etc, according to India’s Ministry of Petroleum and Natural Gas.
In 2004, liquefied Natural Gas was imported from Qatar and LNG terminal was set up at Dahej of 5 MMTPA capacity.
Although it is possible to produce natural gas from gas hydrates, there are significant technical challenges, depending on the location and type of formation, USGS said. 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.
As such, the second expedition focused the exploration and discovery of highly concentrated gas hydrate occurrences in sand reservoirs.
The gas hydrate discovered during the second expedition 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 what we believe to be 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.”
The international team of scientists was led by the Oil and Natural Gas Corporation Limited of India on behalf of the Ministry of Petroleum and Natural Gas India, 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.
The USGS has a globally recognized research program studying natural gas hydrates in deepwater and permafrost settings worldwide. USGS researchers focus on the potential of gas hydrates as an energy resource, the impact of climate change on gas hydrates, and seafloor stability issues. More information can be found about the study and other USGS energy research here.