Drilling for the ultimate thermopower
The Deep Drilling Project might lead to boreholes that could ultimately yield 10 times as much geothermal power as any previous geothermal project.
In December 2007 a well was drilled close to the future IDDP site at Krafla that had a wellhead pressure of 128 bar, the well being full of superheated steam. (Photo: Crestock)
The Iceland Deep Drilling Project (IDDP) plans to drill boreholes deep enough to penetrate the supercritical zones believed to exist beneath three geothermal systems that are already in use. The main aim is to produce much higher enthalpy fluids for power production than are currently being used.
"Shallow" wells
High temperature geothermal resources in Iceland, at the major volcanic centres, have been tapped for steam and water to generate electric power and heat for district heating. Over 200 high-temperature wells have been drilled to depths of two to three kilometres where the temperature is above 300°C.
Deep wells
Since 2002, preparations have been under way to drill wells that are four to five kilometres deep in order to investige the root of the geothermal systems. The aim is to find out if it is economically feasible to extract energy and chemicals where the temperature and pressure may be above the critical point for fresh water. By circulating large quantities of cold water during the drilling, the temperature inside the well might sink below 250°C, allowing the use of conventional drilling tools and practices.
Superheated steam - corrosive gases
In December 2007 a well was drilled close to the future IDDP site at Krafla that had a wellhead pressure of 128 bar, the well being full of superheated steam. The steam had corrosive acid gases and thus the bottom of the well was plugged with cement. It is expected that hydrocloric acid will also be found in the deep well, but by keeping the steam from condensing or coming in contact with water inside the well, such corrosion on the steel casing can be avoided. On the 25th of November 2008 a very successful spot coring test was performed at 2800 metres depth in the production well RN-17 B at Reykjanes.
The IDDP is being funded by Deep Vision, a consortium of Icelandic energy companies.
Further reading:
Drilling plans of the Iceland Deep Drilling Project (National Geological congress Oslo)
Iceland Drilling Project (International Continental Scientific Drilling Program)
Iceland Deep Drilling Project
The main purpose of the IDDP project is to find out if it is economically feasible to extract energy and chemicals from hydrothermal systems at supercritical conditions. To study the supercritical hydrous fluid, an advanced drilling technology needs to be applied and a novel fluid handling and evaluation system designed.
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