Beschreibung
Drilling of IDDP-1
The first full scale IDDP-1 well was meant to be completed to 4.5 km depth late summer 2009 and the first flow test to be performed some months later. However, that drilling operation was abruptly terminated by late June at 2.1 km depth when drilling penetrated molten rock. Rapidly quenched magma of rhyolitic composition was returned to the surface in the form of quenched obsidian glass that plugged the lowest 20 m of the hole. Fortunately, due to earlier drilling problems, the well had been cased down to 1958 m depth, and was completed with a slotted liner down to 2080 m depth. This was in preparation for a flow test of the superheated regime just above a magma chamber, which should be performed autumn 2009. The flow test began in March 2010, and by July 2010 the well was producing some 30 kg/s of 330°C hot superheated steam at 16,5 bar-g pressure, and is still heating. This corresponds to some 20 MW of electric power.
ICDP Status Report 2017
The Iceland Deep Drilling Project (IDDP) is a long-term program by an industry-science-government consortium aimed at investigating very high temperature, supercritical geothermal systems as a way of improving the economics of geothermal energy production. A feasibility study indicated that a well tapping naturally occurring supercritical fluids would produce a power output an order of magnitude greater than that from a 300 °C geothermal well. However reaching a supercritical geothermal reservoir requires drilling to depths of 4 to 5 km, with temperatures in the range of 450-600 °C. In 2009 the well IDDP-1 was drilled to test this concept at Krafla in NE Iceland, planned to reach 4.5 km depth. Drilling had to be terminated at only 2.1 km depth when 900 °C rhyolitic magma was encountered. The borehole was completed as a subcritical well producing steam from the contact zone of the intrusion but casing and cementation were too unstable to maintain the well open for a power production.
IDDP-2 well drilling for supercritical fluids from at least 4.5 km depth started in August 2016 on the Reykjanes Peninsula in SW Iceland on the landward extension of the Mid-Atlantic Ridge and lasted until January 2017. The hydrothermal fluid in the Reykjanes geothermal field is modified seawater, thus this deep well will be the first opportunity worldwide to sample the root zone of a magma-hydrothermal system similar to those that are the sources of the black smokers on the planet-encircling mid-ocean ridges. The hole reached a depth of 4626 m and nine coring runs have been performed producing four drill cores for research. High-temperature geophysical downhole logging confirmed the presence of supercritical fluids with bottom hole temperature of 427 °C and fluid pressure of 34 MPa.