Status Quo of Demonstration Sites
To demonstrate the DESTRESS concept, six different sites with access to a reservoir by means of geothermal wells have been chosen. About 9 month after the start of the project, we present here the first status quo report on the demonstration sites.
Klaipeda
Several visits at Klaipeda by the involved partners targeted the investigation of the continuing injectivity challenges in Klaipeda. Due to the manifold reasons for those challenges, they included laboratory experiments, the study of historical data and measurements in the field. Results show limitated impact of former reservoir treatments and therefore suggest to focus on subsurface hydrochemical, biogeochemical and hydraulical transport processes. For final evaluations and decision making about further reservoir treatments the team of GFZ met GTN and Geoterma in mid November. The planned soft stimulation treatment for Klaipeda site consists now of a combined chemical-mechanical conditioning. A detailed version of the strategy will be drafted by the end of the year and circulated for discussions between the partners in the beginning of 2017.
Pohang
Following the first hydraulic stimulation in PX-2 at a depth of 4.35 km early this year, NexGeo has recently successfully completed the side-tracking of PX-1 deep borehole in close consultation with GES for mud weight control and well completion. The second hydraulic stimulation in the PX-1 at >4.2 km (TVD) and will take place in December. Because of a large, natural earthquake (ML 5.8) occuring around 40 km away from the site last September, all the consortium members, especially from GFZ and GES, are making every effort to minimize the seismic hazard through the soft stimulation strategy. In the first half of 2017, complementary hydraulic stimulation on PX-2, and circulation test between PX-1 and PX-2 are planned with eventual installation of binary a power plant on site.
Rittershoffen
After the inauguration in June 2016, thermal, chemical and hydraulic reservoir treatments have been performed. The aim in DESTRESS is to interpret the hydraulic, thermal, logging and seismic data. In September 2016, more than 100 people visited the Rittershoffen site during the European Geothermal Congress. For the next six months, geothermal operations and technical maintenance are planned as well as continuous seismic monitoring.
Soultz-sous-Forêts
After an extensive renovation, Soultz has been reopened in September 2016. Three wells are targeting now crystalline rocks in 5 km depth. A new ORC (Organic Rankine Cycle) plant has been erected and produces 1.7 MWe gross power from a deep post-stimulated fractured granite. After the set up of the down-hole production pump in June 2016, the geothermal operations started successfully. To improve the poor injectivity of the GPK4 well, the reservoir will be treated by soft chemicals. During the European Geothermal Congress, more than 100 people visited the Soultz site. In the coming months, non-standard risk monitoring (WP3.4) will be implemented around the Soultz power plant in the framework of DESTRESS and a feasibility study for chemical treatments in at Soultz is due by the end of 2016.
Westland
As the feasibility of the project in the Triassic aquifer is unclear, a fall-back scenario to a shallower (approx. 2250 m) Cretaceous aquifer was developed. After drilling and testing the first Triassic well (NLW-GT-01), Trias Westland will decide about the drilling of the second Triassic well (NLW-GT-02) and decide if the second well will be completed and tested in the Lower Cretaceous (NLW-GT-03). In case of the completion of the Lower Cretaceous aquifer, the deep part of the first Triassic well (NLW-GT-01) will be plugged and perforated at the Lower Cretaceous depth. At this moment, the tender for the mining installation has been granted and the tender for the drilling, services and materials is currently on goging. The expected spud date for NLW-GT-01 is September 2017.
