The first iceland deep drilling project well to be drilled this year in Krafla, NE-Iceland
|Location||International Geological Congress,oslo 2008|
|Author||Fridleifsson, Gudmundur O۱; Elders, Wilfred A.۲|
|Holding Date||08 October 2008|
In August 2008, the drilling of the first Iceland Deep Drilling Project (IDDP) drillhole will commence in the Krafla geothermal field, NE-Iceland, operated by Landsvirkjun, a leading Icelandic energy company. This is part of the IDDP programme to investigate whether it is technically and economically feasible to produce geothermal energy from systems at supercritical conditions. This will require drilling to depths of 4 to 5 km in order to reach temperatures of 400 to 600°C. It is estimated that producing steam from such a well could generate 40 to 50 MW electric. If the IDDP’s test of this concept proves successful, it could lead to major improvements in the economics of high-temperature geothermal resources in Iceland and elsewhere. However, deep drilling for high pressure, high temperature and potentially chemically hostile fluids calls for careful drillhole design and engineering. Similarly, dealing with supercritical hydrous fluids of unknown chemical composition involves technical challenges that will require sophisticated solutions and extensive fluid testing before large scale power generation can be realized.. In order to describe the status of the IDDP in some detail at this congress we decided to make a series of contributions, one dealing with the general concept and the scientific interest in IDDP (Elders and Fridleifsson, this volume); the second dealing with the geology and hydrothermal conditions in the Krafla high temperature field (this abstract), the third dealing with the fluid chemistry and the plan to handle and evaluate the hostile fluid (Armannsson et al, this volume), and the fourth describing the drilling and coring technology (Thorhallsson et al., this volume). Funding for drilling and fluid testing of the first IDDP well at Krafla is already secured and this drilling is expected to take some 4-5 months. The well will then be flow tested in 2009.
The geology and hydrothermal alteration of the Krafla Central Volcano (KCV) is well known from detailed geological mapping, and by extensive exploratory and production drilling since 1971. During 1975-1984, a volcanic episode was experienced within the Krafla volcano, involving 9 volcanic eruptions and some 15 subsidence and uplifting events. The volcanic activity severely affected some of the Krafla drill fields, which could not be used for the following decade, but at the same time a huge magma chamber at 3-7 km depth was detected by S-wave attenuation within the centre of the Krafla caldera, obviously the heat source of the presently active geothermal system. A recent MT-survey has confirmed the existence of a low resistivity bodies at shallow depths within the volcano. Thus the selection of the first drill site for the IDDP well is based on a wealth of geological, geophysical and geochemical data that will be described at this congress.