IIT Madras team tries to extract methane from ice-like cages

Chennai: Indian Institute of Technology Madras researchers are developing new techniques for extracting methane from natural gas hydrates. Methane is a lower cost option for people and businesses who need power and heat. Methane, in the form of natural gas, has several uses of immense industrial importance. Food processors, petroleum refineries, clay and glass industries, paper and pulp industries and fertilizer industries use natural gas for its various unit processes.

There has been worldwide interest in the development of techniques to extract methane gas trapped in 'Gas hydrates', present in shallow sediments along continental coastlines. (' gas hydrates' are water-based crystalline solids, resembling ice. Molecules of liquid or gas remain trapped within the gas hydrates).

Hydrates are particularly promising methane sources in India because nearly 1,900 trillion cubic meters of methane gas lie untapped in these cages within the waters of the Indian Exclusive Economic Zone. This is 1,500 times more than the country's present gas reserve. Krishna-Godavari basin and Andaman Basin has also large amounts of gas hydrates, according to the reports of The Ministry of Earth Sciences, Govt of India.This IIT Madras research towards developing techniques to extract methane from gas hydrates can enable the indigenous supply of natural gas and potentially lighten the nation's natural gas import burden. It is believed that the energy content of methane occurring in hydrate form is immense, possibly exceeding the combined energy content of all other known fossil fuels.

The research is being headed by Dr Jitendra Sangwai, professor (Petroleum Engineering), Department of Ocean Engineering, IIT Madras and includes research scholars Mr Pawan Gupta and Mr Vishnu C. His research is being funded by IIT Madras and Department of Science and Technology (DST), Govt. of India.

Speaking about the importance of this research, Dr Jitendra Sangwai said, "Research is underway around the world to develop methods to extract methane from gas hydrates from both clayey and sand-dominated reservoirs. The Krishna-Godavari basin is a clayey reservoir while the off-shore Indian peninsular ones are a mix of both clayey and sandy. As gas hydrates are comparatively immobile and impermeable, they need to be dissociated into their constituent gas and water before the methane recovery from hydrate reservoirs is possible."Four methods are being studied for this dissociation- thermal stimulation, depressurisation, chemical injection and carbon dioxide injection. While depressurisation is the most energy-efficient production approach for extracting gases from clayey hydrates, a combination of thermal stimulation and depressurization is more efficient to extract methane, than either of the methods individually, they noted. The team has also been researching extraction of methane from hydrates(compounds chemically combined with water). However, polymer flooding has not yet been applied to methane recovery from gas hydrates.