The Iceland Deep Drilling Project (IDDP) is a long term study of high-temperature hydrothermal systems in Iceland. The IDDP is a collaborative effort by a consortium of three Icelandic power companies (Hitaveita Sudurnesja (HS) (since 2008: HS Orka hf), Landsvirkjun (LV) and Orkuveita Reykjavíkur (OR)), and Orkustofnun (OS), the National Energy Authority of Iceland. and the Icelandic government, formed to determine if utilizing supercritical geothermal fluids would improve the economics of power productions from geothermal fields.
The IDDP expects to drill and test a series of boreholes that will penetrate supercritical zones believed to be present beneath three currently exploited geothermal fields in Iceland. One has been excecuted and the second will be activated in mid september 2016. A drilling to a depth of about 5 km will be required in order to reach hydrothermal fluids at temperatures ranging from 450°C to ~600°C.
A feasibility study completed in 2003 points at that in comparison to the output from conventional geothermal wells, which are 2.5 km deep, a ten-fold increase in power output per well could result if fluid is produced from reservoirs hotter than 450°C .
A typical 2.5 km-deep geothermal well in Iceland yields power to approximately 5 MWe. Assuming a similar volumetric inflow rate of steam, an IDDP well tapping a supercritical reservoir at temperatures above 450°C and at a pressure of 23-26 MPa may be expected to yield ~50 MWe.
The first IDDP drilling was performed in year 2009 in Krafla. The second drilling is scheduled mid september 2016 at the Reykjanes geothermal field. The aim is to drill 3 km deep. The drill Thor is powered by green energy produced by Reykjanes power plant.
The main benefits from deep geothermal drilling are as here below:
- Increased power output per well, assumed by an order of magnitude, and production of higher-value, high-pressure, high-temperature steam.
- Development of an environmentally benign, high-enthalpy energy source below currently producing geothermal fields.
- Extended lifetime of the exploited geothermal reservoirs and power generation facilities.
- Re-evaluation of the geothermal resource base.
- Industrial, educational, and economic spin-off.
- Knowledge of permeabilities within drillfields below 2 km depth.
- Knowledge of heat transfer from magma to water.
- Heat sweeping by injection of water into hot, deep wells.
- Advances in research on ocean floor hydrothermal systems.
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