The IDDP was founded in the year 2000 by a consortium of three Icelandic energy companies: (Hitaveita Sudurnesja (HS) (since 2008: HS Orka hf), Landsvirkjun (LV) and Orkuveita Reykjavíkur (OR)), and Orkustofnun (OS), the National Energy Authority of Iceland. The consortium began by preparing the drilling of a 4-5 km deep drill hole into one of its high-temperature hydrothermal system in order to reach 400-600°C hot supercritical hydrous fluid at a rifted plate margin on a mid-ocean ridge. A feasibility report was completed in 2003. The IDDP is a long term research and development project which will take a decade or two to conclude. As yet, IDDP is therefore not an alternative solution to meet energy demand in the near or intermediate future.
ICDP (International Continental Scientific Drilling Program) granted financial supports to organize the scientific program. A start-up meeting was held in Reykjavík in June 2001, and two workshops were held at Nesjavellir in 2002, the earlier on drilling technology in March, the latter in October on science. As a result of this IDDP received approximately 60 research proposals from the international scientific community, which ranged from petrology and petrophysics to fluid chemistry, water rock reactions, surface and borehole geophysics and reservoir modelling. More than half of these proposals require drill core samples.
In 2003 a decision was reached to drill the first IDDP candidate well at Reykjanes. The first IDDP candidate well, RN-17, was drilled at Reykjanes in 2004-2005 down to 3082 m depth by HS. In 2005 funding for drilling the first IDDP well to 5 km depth at Reykjanes was secured by the energy consortium, together with ICDP and the US National Science Foundation (NSF) which will participate in funding core drilling for scientific research. Unfortunately, this 3 km deep well of opportunity at Reykjanes became blocked during a production test in November 2005, and after attempts failed to recondition it, the well had to be abandoned in February 2006. Later the same year IDDP decided to move to the Krafla high temperature field in NE-Iceland, to attempt drilling a full size IDDP well into supercritical conditions, a well that was later identified as well IDDP-1. Alcoa Inc, an international aluminum company, joined IDDP consortium as funding partner in 2007, and StatoilHydro ASA (now Statoil), a Norwegian oil company, joined the consortium in 2008. For historical review until 2010 see: 3902 Fridleifsson et al.
The main purpose of the IDDP project is to find out if it is economically feasible to extract energy and chemicals out of 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. The improvement of this basic idea by the IDDP is to drill deep enough into the roots of a conventional high temperature hydrothermal system to produce water at supercritical conditions and bring it to the surface as 400-600°C superheated steam, at subcritical pressures (<220 bar). In the case of low permeability systems, by injecting cold fluid into the hot rocks, fractures can be induced to complete the thermal mining cycle.
The main result of the feasibility study
The first step was to design the project in a feasibility report, extending from the geo-scientific background and site selection to drilling technology and fluid handling and evaluation. The main results of the feasibility study were the following: (i) It is possible to drill the IDDP well to 5 km, (ii) It is possible to deal with a 400-600°C hot fluid, (iii) it is not possible to predict the chemical composition of the fluid prior to drilling, (iv) Some 12 potential drill sites for IDDP wells were selected, (v) Estimated cost of a full scale IDDP well: U$ 14-16 millions, (vi) Estimated cost of 5 km deep production well: US$ 8-9 millions, (vii) Estimated cost of coring to 4 km depth in “wells of opportunity”: US $ 6 millions, (viii) Estimated cost of fluid handling and evaluation by using the “pipe”: US $ 5,5 millions. (ix) The IDDP wells should also be considered for fluid injection tests in order to gain experience in heat sweeping (enhanced geothermal systems (EGS)), (x) The knowledge gained by the IDDP experiment will be beneficial to the energy company holding the geothermal field, irrespective of the result to meet the IDDP primary goal of tapping supercritical fluid from a geothermal system.
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. For closer details on the drilling and the flow test of IDDP-1 see this webpage from 27 May and 7 July 2010.
Future IDDP Drilling and production testing
Despite the fact that the primary goal of IDDP-1 to drill down to and test a hydrothermal system at supercritical condition was not met by the first IDDP well at Krafla in 2009, the IDDP program intends to move forward . IDDP plans to drill wells IDDP-2 and IDDP-3 in 2011-2015, at the Hengill and the Reykjanes geothermal systems in SW-Iceland. Additional funding for completing both these wells to target depths and subsequent flow and production testing is required – an opportunity for further international collaborations in IDDP.
Potential Benefits of the IDDP:
- Increased power output per well, perhaps 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.
- Possible extraction of valuable chemical products?
- Advances in research on ocean floor hydrothermal systems.