| Abstract |
The Iceland Deep Drilling Project (IDDP) is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs. Modelling 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 intends to drill 4-5 km deep wells in three different high–temperature geothermal fields in Iceland, Krafla, Hengill and Reykjanes. The drilling of the IDDP -1 took place at Krafla in 2009, but had to be terminated at 2.1 km depth when the borehole drilled into more than 900°C molten rhyolitic magma. The borehole was completed as a production well and proved to be highly productive, estimated to be capable of generating 25-35 MWe from dry superheated steam, produced from a contact zone above the magma intrusion. With a wellhead flowing temperature of 450°C and enthalpy around 3200 kJ/kg, it holds claim to be the hottest producing geothermal well in the world. In July 2012 flow testing to optimize utilization had to be temporarily terminated for repair of the flowline valves after more than 2 years of testing. P lans are underway to drill a new 4-5 km deep well at the Reykjanes field in 2014-2015. An international IDDP - ICDP Workshop was conducted in Iceland, September 2012, in order to discuss and evaluate the IDDP -1 situation and plan ahead for IDDP -2. No issues were identified that should rule out attempting the drilling, sampling and testing of the proposed IDDP -2 well. The consensus of the workshop was that the drilling of such a hot, deep well, and producing from potentially hostile, supercritical or superheated fluids, although technically very challenging, is possible but requires careful contingency planning. |