IIT-M working on extracting methane from gas hydrates

As there has been worldwide interest in the development of techniques to extract methane gas trapped in ice-like crystalline cages called ‘Gas hydrates,’ which are present in shallow sediments along continental coastlines, the IIT Madras research towards developing techniques to extract methane from gas hydrates can enable indigenous supply of natural gas and potentially lighten the nation’s natural gas import burden.

Hydrates are particularly promising methane sources in the country since 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 country’s present gas reserve”, researchers at IIT Madras said on Tuesday.

The research is being headed by Dr Jitendra Sangwai, professor (petroleum engineering), Department of Ocean Engineering, IIT Madras, who studies state-of-art processes used to recover crude oil from offshore reservoirs in India.

The Ministry of Earth Sciences reports that Krishna-Godhavari basin and Andaman Basin have large amounts of gas hydrates.

Stating that the Krishna-Godhavari basin is a clayey (clay rocks) reservoir while the off-shore Indian peninsular ones are a mix of both clayey and sandy, Dr Sangwai said 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.

He said the IIT Madras research team has also studied polymer flooding, the synthetic component, for the extraction of methane from hydrates.

“This method is already used for oil recovery from matured crude oil fields,” he said, and added “polymer flooding helps in establishing a stable waterfront at the water-oil interface and improves the sweep efficiency of the reservoir”.

Controlled extraction of methane from gas hydrates can not only meet the enormous demand for energy all over the world, but can also reduce detrimental geological release of greenhouse gas into the environment from these sources, according to theresearch team.