Innovative soft geothermal reservoir stimulation project started in Pohang, Korea

Drilling rig on project site in Pohang/ South Korea (source: DESTRESS Project)

Alexander Richter 17 Dec 2016

This week, the first soft stimulation of a deep geothermal borehole in Pohang, Korea started.  This is the first stimulation done as part of the DESTRESS project started in March 2016, which is funded by the European Union, the Swiss Confederation and the National Research Foundation of Korea.  DESTRESS stands for Demonstration of soft stimulation treatments of geothermal reservoirs funded under the Horizon 2020 reasearch and innovation programme under grant agreement No.691728, with a total funding amount of around EUR 25 million.

The following is a statement by the project team.

DESTRESS focuses on soft stimulation techniques, which aim to achieve enhanced reservoir performance while minimizing environmental impacts including induced seismicity. It comprises methods such as cyclic or fatigue, multi-stage, chemical and thermal stimulation.

With its emphasis on soft stimulation, the primary objective of DESTRESS is to develop a comprehensive compilation of good practices for successful geothermal projects through demonstration and research. A strong cooperation between eight academic and eight industrial partners from Europe and South Korea within the project aspires to expand knowledge and to provide solutions for a more economical, sustainable and environmentally responsible exploitation of underground heat. The concepts developed within DESTRESS are based on experience in previous projects, on developments in other fields, mainly the oil and gas sector, and on scientific progress made on topics such as fluid-rock interaction enabling the application of a soft stimulation approach, more accurate determination of the stress field and the analysis of induced seismicity.

Besides Pohang, DESTRESS involves other geothermal sites: Haute-Sorne in Switzerland, Soultz-sous-Forêts and Rittershoffen in France, Klaipeda in Lithuania and Westland in the Netherlands. A wide range of laboratory experiments, drilling, monitoring and stimulation operations will be implemented case specific. The techniques applied at the DESTRESS demonstration sites are designed to be transferable to other geological settings, so that the concepts can become the basis for a standardised procedure in the development of EGS projects.

One aim of DESTRESS is to bring together social and economic challenges related to soft stimulation. An initial step for this task is to investigate possible risks: even though soft stimulation aspires to reduce the environmental impact of a reservoir enhancement, not every risk can be excluded. At an event held earlier this year in Karlsruhe/ Germany,  experts from various DESTRESS project partners identified and described 37 risks that were prioritized by conducting a worst case evaluation, in which different monetary and probability categories
were assigned. As one of the main results, a preliminary list of the top 10 risks is available now consisting of blow out, fluid-fluid interactions (thermal brine and chemicals), fluid-rock interactions, induced seismicity (with time delay after injection), induced seismicity exceeding threshold, lack of information, loss in hole (measuring tool), political instability, public acceptance and unwanted subsurface hydraulic connections. The risk assessment results will be further evaluated and serve to prioritize the research efforts in the years
to come.

The above map shows the project sites in Europe and South Korea.

If you are interested in staying informed, you can subscribe to the DESTRESS newsletter: www.destress-h2020.eu/stay-informed/newsletter/  or email at destress@sed.ethz.ch

Source: DESTRESS website