| Abstract |
The Iceland Deep Drilling Project (IDDP) is being carried out by an international industry-government consortium in Iceland, in order to investigate the economic feasibility of producing electricity from supercritical geothermal reservoirs. Modeling suggests that producing superheated steam from a supercritical reservoir could potentially increase power output of geothermal wells by an order of magnitude. To test this concept, the consortium planned to drill a deep well in each of three different geothermal fields in Iceland, namely, Krafla, and at the Hengill and Reykjanes fields in SW-Iceland. In 2009 the drilling of the first deep well, IDDP-1, was attempted in the active central volcano at Krafla in NE Iceland. However the drilling had to be terminated at 2.1 km depth when 900°C rhyolite magma was intersected. The well, IDDP-1, was highly productive, capable of producing some 25 MWe from 380°C superheated steam during a flow test undertaken in 2010. The well was shut in August 2010, to allow the wellhead and surface equipment to be modified to withstand corrosive fluids. Starting in May 2011 flow-testing, wet and dry scrubbing of the steam and a test of a heat exchange system will be conducted. This flow test is expected to last through the rest of 2011. Preliminary results from these tests should be available to report at the GRC Annual Meeting in October 2011. The second deep IDDP well, IDDP-2, could possibly be drilled to 4-5 km depth as early as 2012-2013, into the saline Reykjanes high-temperature field in SW-Iceland. The design of the IDDP-2 well will benefit from lessons learned during drilling of the IDDP-1 at Krafla. Here we review the geological and geophysical characteristics of the Reykjanes field, based on pre-existing and very recent data. According to both 1 dimensional and 3 dimensional interpretations of the new magnetotelluric (MT) data, the IDDP-2 site is located above a major heat source occurring at some 10 km depth. |