To drill and complete a well bottomed at molten magma seems to be a mad scientist-type cliché, but if it could be done, it would be the holy grail of geothermal power development. A new drilling project in Iceland, the Krafla Magma Testbed, is taking on the challenge.
Journey to Krafla
In 1975, Iceland planned to build a geothermal power plant at Krafla, a 10-kilometer-wide volcanic caldera in the country’s northeast. One of the wells drilled, K-4, experienced an uncontrollable blowout that lasted several months prior to the well’s collapse. Many at the time thought the well had hit acidic steam that corroded the casing. Later, researchers realized that the well had actually hit active magma. Seismic activity associated with Krafla’s volcanic eruptions from 1975 to 1984 enabled scientists to map the magma chamber beneath the volcano.
Iceland’s national power company, Landsvirkjun, installed the first turbine in the Krafla Geothermal Station in 1985 with 30 megawatts of capacity. It built the second turbine 14 years later with the same electricity generation capacity.
Between 2006 and 2009, Landsvirkjun attempted to expand the Krafla Geothermal Field, drilling four new wells, one of which hit acidic flow at 2,500 meters deep. In 2009, the Iceland Deep Drilling Project drilled a well at Krafka. The well design anticipated hitting magma at 4,500 meters, but the drill bit broke off at 2,094 meters. Two side-track wells met the same fate. Like KJ-39, the IDDP-1 boreholes had intersected rhyolitic magma.
The IDDP-1 drill and a few other drills at Krafla indicate that the well encountered two types of quenched volcanic silicic glass while drilling into a hot lava flow:
- Clear glass and felsite that is lower degree partial melt and flushed out of the well first
- Brown glass that is higher degree partial melt and lies beneath the clear glass
These two glasses indicate separate magma differentiation and quenching processes that were triggered by decompression-induced degassing as the borehole intersected magma. The glass particles had dissolved water contents from 1.3 to 2 weight percent. The IDDP-1 observation was a small-scale natural experiment of much larger decompressional melting of magma that occurs in mid-ocean ridges.
Krafla Magma Testbed
The new project, KMT, builds upon the IDDP experience. “The IDDP-1 well,” according to Björn Þór Guðmundsson, CEO at KMT, “was flow tested on and off for almost two years and turned out to be ten times more powerful than an average geothermal well.” Water becomes a superheated steam at temperatures above 374 degrees Celsius, which carries more thermal energy to turn turbines.
“KMT’s primary funding agencies include the International Continental Scientific Drilling Program, Iceland’s Ministry of the Environment, Energy and Climate, Landsvirkjun, Reykjavik Energy and the Iceland Drilling Company,” Guðmundsson said. The project will collaborate with more than 15 universities, research institutes and corporations.
Drilling is scheduled to begin in 2027 and plans to reach a depth of 2,100 meters. KMT is addressing challenges around drilling into extremely hot and pressurized environments: 500 degrees Celsius and 15 megapascal. “The main challenges,” Guðmundsson said, “are well integrity issues, thermal stress, corrosion, cement and cementing techniques, and also measurements that we plan to do in the wells.”
KMT has been dubbed the first “magma observatory.” It will not only extend geothermal power development deeper but also “offer unique opportunities to enhance volcanic monitoring by directly accessing and instrumenting magma systems,” according to Guðmundsson. Drilling into magma has just begun.