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Multidisciplinary and multi-context demonstration of EGS exploration and Exploitation Techniques and potentials

Periodic Reporting for period 1 - MEET (Multidisciplinary and multi-context demonstration of EGS exploration and Exploitation Techniques and potentials)

Reporting period: 2018-05-01 to 2019-10-31

Europe is sleeping over a giant yet largely unused source of renewable energy: geothermal energy which can produce both heat and electricity. A part of this natural heat, namely Enhanced Geothermal System (EGS), is a new approach which generates great hopes in the world. The basic concept of the approach is to exploit the heat which is trapped in any geological settings with several configurations for rock composition, tectonic setting and stress field. To overcome several challenges, the MEET project goals are:
• To capitalize on the exploitation of the widest range of fluid temperature in EGS (Enhanced geothermal systems) plants and abandoned oil wells.
• To demonstrate the lower cost of small-scale production of electricity and heat in wider areas with various geological environments, in order to support a large increase of geothermal-based production sites in Europe in a near future.
• To demonstrate the viability and sustainability of EGS with electric and thermal power generation in all kinds of geological settings with 4 main types of rocks: granitic, volcanic, sedimentary and metamorphic with various degrees of tectonic overprint by faulting and folding
The MEET project has been started on May the 1st of 2018. The kick-off meeting (KOM) was done on 17 and 18th of May 2018 in Strasbourg, France. After 18 months of activities, many achievements have already been done according to the various geological conditions investigated for developing EGS in Europe. Some multi-disciplinary transversal items like modeling strategies, sampling strategies and relevant key parameter evaluation for economics have been studied. For sedimentary reservoirs, many achievements have been done related both to reservoir assessment and to existing oil well facilities. For the demonstration of heat production from oil wells, following actions have been done. Regarding the demonstration of electricity generation from oil wells, the first ORC test is nearly ready to start in Chaunoy. Finally, work has deeply progress to better understand deep Triassic reservoirs in Parisian Basin. In granitic rocks, several investigations were done from laboratory, field scale, modelling, drilling site and demosites. Regarding Soultz-sous-Forêts reservoirs understanding and its analogue in Noble Hills, a lot of work have been performed (innovative reinterpretation of borehole data, detailed analyses of fractures along Soultz and Basel wells, Work on Offset Vertical Seismic Profile (OVSP)…). For demonstration of additional energy valorisation on existing EGS plant, a series of operational work have been undertaken: 1)A first heat exchanger has been installed from January to April 2019 to test colder reinjection (40°C) in operational conditions on the Soultz geothermal site on 10% of flow rate. 2) In parallel of this test, design of the ORC that will be installed in Soultz-sous-Forêts site and the validation of the Soultz-sous-Forêts thermal data have been completed. Regarding the upscaling of EGS plants, MEET partners have work on transportation technologies for medium to high temperature brines over rather long distances. Both materials and connections technologies have been reviewed to prepare specifications for hot and “cold” transportation pipes. Tenders have been launched base on these specification and suppliers chosen.For chemical stimulation in Cornwall granitic site (United Downs Deep Geothermal Project), preparatory work has also well advanced: drilling activities of both wells are completed. In parallel, sampling and analyses strategies have been elaborated. For metamorphic rocks, field works have been starting for investigating the geothermal potential of poorly explored areas from basement rocks of Europe. For volcanics rocks, it is planned to run 2 mobile ORC units in Iceland to demonstrate small scale electricity generation in this geological setting.Thus various scientific tasks are well advanced like (1) inventory, review and analyses of literature, information and data from existing demo-sites, (2) new field data acquisition on demo-sites analogues including 3D mapping and sampling with (3) subsequent laboratory analyses and (4) reservoir modelling. On-site operations were launched with (5) heat exchanger test at Soultz and corrosion experiments at Cazaux, Reykjanes and Grásteinn were completed that lead to (6) chose appropriate metallurgies for ORC heat exchangers and (7) finalize 3 first ORCs designs and (8) start ORC manufacturing which should be ready for end of 2019. In parallel (9) mapping of heat resources and needs around oil facilities lead to (10) chose the demo-site for demonstration of heat production and (11) start detailed implementation study.To integrate all the results, the development of a decision-making tool has started including major influencing factors on EGS development.
Also, dissemination was quite intense with several participations to EU scientific events (conferences, workshop). A special focus was done on cross-over events where best practices between oil and gas industry and geothermal industry. MEET project has been presented as a whole in several events involv
The first reinjection test at 40°C done on Soultz-sous-Forêts power plant during 3 month in 2019 is thus a first achievement toward this objective. First analyses on scaling during this test don’t show any evidence of silica precipitation which was a major concern for opertor in Upper Rhine Graben. It also gives insights on metallurgies to recommend or to avoid while decreasing reinjection temperature int his geological setting. In term of temperature loss at production well, first hydrothermal modeling shows a few degrees impact over 30 years of exploitation, which seems reasonable compared to the energy gained.
Thermal power and low temperature-based electric power in sedimentary basin
Within MEET project, Vermilion inventorised and analysed thermal capacities of its whole portfolio in France. Thus a potential over 30 MWth has been assessed on wells and oil dépôts disseminated over Parisian and Aquitanian basins. A first review of end users around some of vermilion facilities lead to the emergence of 6 projects to valorize heat from oil facilities. A first demonstration project in Condorcet High School has been chosen as MEET demo-site to this evolution toward the coproduction of oil and geothermal energy. Indeed, in this case, heat provided by the oil field could replace up to 90% of current energy needs of this high school.
Demonstrate electric and thermal power generation in different geological settings
First in-situ tests by MEET partners lead to highlight what material are the most adequate for various geological conditions (sedimentalry oil fields, volcanic settings and granitic setting in Upper Rhine graben). Indeed these promising results and the adapatability of ENOGIA ORC technology convince ECOGI, the owner Rittershoffen heat plant (Alsace, France) to launch preliminary studies for the installation of such ORC units to valorise the heat still present in reinjected water (~80°C).
In adddition, the selection of second demosite on an rather isolated farm in Iceland should be a good way to promote this small scale technology in Iceland.