Drilling Complete on Australian Hot Dry Rock
Project
EERE Network News - 2/23/08
The first commercial attempt to create a commercial geothermal power plant
using hot dry rock technology reached a crucial milestone on Tuesday, when a
production well successfully reached its target depth. Hot dry rock
technology was invented to draw energy from deep underground areas where
geothermal heat is abundant, but no water exists to carry the heat to the
surface. To tap the energy in this hot dry rock, a well is drilled into it
and water is injected at high pressure, forming fissures in the rock to
create a geothermal "reservoir" consisting of water-impregnated fractured
rock. At least one "production" well is then drilled into the reservoir to
draw the hot water back to the surface. A completed facility would direct
the hot fluid from the production well to a power plant, which would extract
the heat from it to produce power, after which the cooled fluid would be
injected back into the ground.
Geodynamics has been trying for years to establish a geothermal reservoir
deep below the surface of the Australian outback. The company successfully
completed its first well, Habanero 1, back in 2003 and established a
reservoir late that year, but suffered multiple problems drilling its first
production well, Habanero 2, which was eventually abandoned. The company
began drilling its new production well, Habanero 3, in mid-August, 2007, but
encountered problems by late October and suspended drilling. Drilling
resumed in late November and proceeded until the drilling was finished
yesterday. The well first intersected the fracture zone at a depth of 13,716
feet, at which time a hydraulic connection was established between Habanero
1 and 3. Drilling then continued to the target depth of 13,850 feet.
The well should be completed within the next week, as all that remains to do
is to insert a liner into the well to maintain its integrity, and then add
the valves and piping needed to control the well. At that point, the company
will be able to perform flow testing on the reservoir to confirm that the
two wells can produce hot geothermal fluid at the temperature and flow rate
needed to sustain a geothermal power plant.
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