Oregon enhanced geothermal well project nears

A field test of a technology known as enhanced geothermal systems could take place in mid-2012 at the inactive Newberry volcanic site in Deschutes County, Ore., 20 miles south of Bend.

Project operator AltaRock Energy Inc., Seattle, would intermittently inject 24 million gal of cold water into an already drilled 10,600-ft well at Newberry.

The water is expected to create fractures, starting about 6,000 ft deep, in a microseismicity process called hydroshear, similar to hydraulic fracturing, after which biodegradable plastic particles are dropped to seal the fractures temporarily.

Then more cold water is dumped, ostensibly creating successive fracture systems as deep as the bottom of the well and as far as 3,000 ft in diameter. After the plastic disintegrates, water could be circulated to create steam to generate electricity at the surface.

How large a fracture system could be created and how much steam it would return at what temperature are unknown. The technology’s likelihood of inducing earthquakes is also a concern.

The US Department of Energy is funding about half of the project’s $43 million cost. The other contributors include AltaRock, Davenport Newberry Holdings LLC, Stamford, Conn., and Google. The US Bureau of Land Management is accepting public comments on the project.

Developing a commercial project is considered to be at least a decade away. A few generating projects exist worldwide in known geothermal resource areas, but AltaRock maintains that if the fractures can be created artificially projects could be sited almost anywhere hot rocks exist near the surface for conventional rigs to drill multiple production wells.