New energy source could reduce US dependence on foreign natural gas supplies

In the past, deposits of ‘gas hydrates’, which consist of pressurised methane trapped in a cage of ice found in many places, including the continental shelves near Japan, Europe, India, the Gulf of Mexico, the US western seaboard and Alaska, have been considered as hazards by geologists and petroleum engineers because of the tremendous pressure under which they are stored. Inadvertent drilling into a gas hydrate deposit releases the pressure, which can blow the pipe out of the well, creating a methane firestorm – particularly hazardous for offshore rigs where workers have nowhere to escape to.

However, researchers at the University of Arizona (UA) have been given a four year, US$2.5 million grant from the US Department of Energy in order to develop a detailed understanding of gas hydrate reservoir characteristics and the geological conditions that cause these deposits to be formed.

The researchers will also be estimating the amount of gas hydrate on the Alaskan North Slope, and pinpointing the deposits. Such estimates currently vary from 6.7 trillion to 66.8 trillion cubic metres, says Department Head of Mining and Geological Engineering (MGE) at UA. “If we want to develop this resource, we have to more accurately determine how much is there and pinpoint the location of the deposits,” she said.

Part of the search includes examining data taken by seismic reflection gathered since the 1970s from explorations for deep oil reserves, although gas hydrate deposits occur within 2,000 feet of the surface – much higher than deep oil reserves.

The UA team is part of a bigger project which is being led by BP Exploration and the Department of Energy. “Some of the attraction of this project for us is not just the geological challenge,” said geosciences Professor Roy Johnson at UA. “While that is tremendously exciting, this project also gives us the opportunity to contribute to better energy resources for the country and the world. We hope that the end result will be cleaner, more plentiful and cheaper energy.”