The ambition of the ground breaking DEEPEGS project, is to explore the possibilities of producing energy from deep geothermal systems which are enhanced following drilling to depths of 4-5 km.
EU-Horizon 2020 Grant
The DEEPEGS project, funded by the European Union Horizon 2020 research and innovation program (grant agreement No. 690771), provided funding of about twenty million euros for research and development of geothermal energy from significant depths (>3 km) in Reykjanes and in France. This is by far the largest grant for a project under Icelandic control by Horizon 2020, and 45% of the grant is allocated to various research in relation to the drilling and testing operations at the demonstration site in Reykjanes.
IDDP – Icelandic Deep Drilling Project
The Icelandic Deep Drilling Project (IDDP) is supported by the Icelandic energy companies (Landsvirkjun, HS Orka and Reykjavik Energy), together with the National Energy Authority. When the first deep well, IDDP-1, was drilled at Krafla in 2008-2009, it encountered molten magma at 900°C, at a depth of 2.1 km, and so drilling had to be terminated. However, the project demonstrated that it was possible to utilize vast amount of energy from superheated steam in rocks just above the magma. Theoretical models suggest that extracted energy from deep geothermal systems may be as much as ten times more powerful than from traditional drilling methods at shallower levels.
Operations began in early August 2016, and a critical milestone was reached on January 25th, 2017, when drilling of IDDP-2 at Reykjanes was concluded at 4659 m depth. HS Orka led the project, with the involvement of ÍSOR and several European (www.deepegs.eu) and American institutes (www.iddp.is). Iceland Drilling Company was in charge of the drilling.
Role of ÍSOR
ÍSORs´ involvement consisted mainly of well design, drilling preparation, consulting, lithological analysis and borehole loggings. In addition, ÍSOR conducted seismic risk assessment associated with the drilling and stimulation of the well. The composition of fluids from the geothermal system down to 5 km depth had to be evaluated because of potential environmental impacts. A new three-dimensional resistivity model for the geothermal system, extending from Reykjanes to Eldvörp, was developed to better understand the distribution of geothermal heat with depth. Furthermore, the conceptual model of the area was updated by adding newly acquired data sets. Numerous projects remain to be carried out in the near future, in cooperation with domestic and international bodies, including petrological and geochemical studies and the evaluation of geothermal system response to enhancement and production. A large part of the DEEPEGS project is to explore and develop materials used in casings suitable for use at very high temperatures (> 400°C), in addition to casing design, which will aid production wells at such temperatures and improve their life span.
The principle objective of this challenging drilling operation was to drill deep into the extreme temperatures and pressures, retrieve drill cores that allow the study of the nature of the rocks and to determine the permeability, if present, at such great depths.
Results: Successful Operations and Unexpected discoveries
All of objectives were achieved. The temperature at the bottom of the well was 426°C but the alteration mineralogy suggests that it is not less than 500°C and hydraulic pressure was 340 bars. At such temperature and pressure, the rocks become metamorphic, i.e. they are partly recrystallized, as evidenced by drill cores, and fluids are superheated (supercritical state). An unexpected discovery was that permeability was present at the most extreme depths.
New door to explore active geothermal systems in Iceland and Worldwide
For the first time ever, scientists have had the opportunity to investigate the roots of an active geothermal system. A door has been opened allowing us access to deep geothermal systems, which contain superheated liquid or steam. This means that it will be possible to harness significantly more energy, with fewer boreholes whilst at the same time, being environmentally friendly and financially attractive. In addition it will be possible to inject wastewater associated with geothermal utilization, back down to 4-5 km depth in order to expand production in geothermal systems at shallower depths and maintain their pressure.
It is clear that the drilling of IDDP-2 will have a significant impact on the development and utilization of geothermal systems, not only in Iceland but throughout the world. Extensive knowledge and experience was gained during the drilling, and further research will continue in the coming years. Finally, the main results of the various technical and financial aspects of the project will be completed by the end of 2019.