Friday, October 2, 2015

Iceland: Report from the Deep Drilling Project

Drilling into magma: the future of electricity production from volcanic geothermal systems? (European Geosciences Union )

Citation: Scott, S., Driesner, T. & Weis, P. Geologic controls on supercritical geothermal resources above magmatic intrusions. Nature Communications. 6:7837 doi: 10.1038/ncomms8837 (2015)

Transparent, opalescent steam discharges from the IDDP-1 borehole
at the Krafla volcano in Iceland. (Image: Kristj√°n Einarsson/IDDP)
Electricity production from high-enthalpy geothermal systems typically involves drilling boreholes into permeable reservoirs at depths of 1-2 km and temperatures between 250-300 °C. The fluid that comes up the wellbore consists of a mixture of liquid and vapor, from which the vapor is separated and passed through a steam turbine to generate on average 3-5 MW per well.

The Iceland Deep Drilling Project (IDDP) was founded by a group of international scientists who sought to drill to deeper, hotter conditions where water is a single-phase, intermediate density, supercritical fluid. Basic thermodynamic considerations suggest that wells drilled into supercritical geothermal resources could potentially provide an order of magnitude more electricity than a conventional geothermal well. 

A plan was developed to drill a borehole to 4-5 km depth in the Krafla geothermal system, with the aim of discovering a reservoir at supercritical temperatures (>374 °C) and pressures (>220 bars).

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