Cold tap

US researchers are developing technologies to tap potentially huge reserves of natural gas locked underground in frozen inhospitable permafrost regions.

According to the US Department of Energy, global volumes of methane hydrate – a compound of water and methane that forms under pressure at cold temperatures – are estimated to be far higher than conventional natural gas resources.

The Hot Ice No. 1 project, a two-year partnership, with costs shared between the US Office of Fossil Energy, Anadarko Petroleum, Maurer Technology and Noble Engineering and Development, is now reaching an end. Although its wells in northern Alaska did not yield commercial quantities of gas hydrates, technological advances made have given cause for celebration.

The project’s Arctic Drilling Platform, a mobile hydrate core analysis laboratory, performed measurements on both the whole core retrieved from the well and on one-inch plugs taken from the full-sized core.

The laboratory, developed at the University of Oklahoma, allows the core to be analysed close to the drill site, and at a reduced temperature. This is important as methane hydrate quickly separates into methane gas and water when warmed. A CAT scan developed by Lawrence Berkeley Laboratory was used to detect concentrations of methane hydrate within cores as they were retrieved from the well.The well also produced a high- resolution 3D vertical seismic profile survey that should help researchers pinpoint the geological strata that identify the presence of hydrate in the area.

The researchers had expected to find gas hydrates during the project. The compound exists beneath large portions of the world’s arctic permafrost, as well as within deep-sea sediments. ‘The sands were there just as expected but we found free gas and water rather than hydrate,’ said Tom Williams, vice-president of Maurer Technology.

‘Clearly, the model for distribution of methane hydrate on Alaska’s North Slope may be more complex than we thought.’

In this first attempt at continuously coring permafrost to detect methane hydrate, the well was cored from a depth of 82ft to 2,300ft, with 93 per cent of the core recovered. The researchers believe that a huge amount of knowledge will be gained for future hydrate exploration through analysis of the collected data.