Guðmundur Ómar Friðleifsson,
HS Orka, Svartsengi, 240 Grindavik, Iceland.
Abstract for GeoEnergi 2017
Significant milestone has been reached in the Iceland Deep Drilling Project at the Reykjanes Peninsula in Iceland when drilling of the IDDP-2 well was completed on the 25th of January at 4,659 meters depth. All of the initial targets were reached. These targets were to drill deep, extract drill cores, measure the temperature and search for permeability. Temperature at the bottom of the well has already been measured at 427°C, with fluid pressure of 340 bars, drill cores were retrieved, and the rocks appear to be permeable at depth. It´s clear that the bottom of the well reached fluids at supercritical conditions, so that the main drilling phase objective of the project has been achieved. The drilling operation took 168 days since we began the drilling operation 11th August 2016.
The depths beneath the production zone of the geothermal field at Reykjanes have never before been explored. The IDDP-2 well took advantage of HS Orka´s well RN-15 at which was a 2,500 meter deep production well. The first phase of the IDDP-2 project was to deepen the RN-15 well to 3,000 meters and cement a steel casing firmly into the surrounding formations. The deepest existing geothermal wells at Reykjanes are about 3,000 meters deep so the IDDP-2 has the deepest casing in any well in Iceland. From there the well was deepened to its final depth of 4,650 m.
If the best outcome of the project is achieved that the well can be used for highly efficient energy production, it would open new dimensions in geothermal utilization. This is because a supercritical fluid has a much higher energy content than conventional high-temperature geothermal steam. Potential utilization will not be known until the end of year 2018 when all research, including substantial well stimulation and flow testing, but first indications are positive. If deep supercritical wells, here and elsewhere in the world, can produce more power than conventional geothermal wells, fewer wells would be needed to produce the same power output, leading to less environmental impact and improved economics. Another option would be to use the IDDP2 for deep injection to enhance the performance of the overlying current production zone of the Reykjanes geothermal field.