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Integrated Methods for Advanced Geothermal Exploration

Final Report Summary - IMAGE (Integrated Methods for Advanced Geothermal Exploration)

Executive Summary:
IMAGE (Integrated Methods for Advanced Geothermal Exploration), received a grant of over €10 million by the European Commission within the 7th Framework Programme for Research and Technological Development (FP7). The project was co-funded for four years (2013-2017) and was completed in October 2017. IMAGE involved 20 partners from 9 different countries.

IMAGE main aim has been to develop exploration methods for an extended resource base, including supercritical and deep basement/sedimentary geothermal reservoirs. IMAGE aimed at the enhancement of relatively low TRL exploration technologies moving from TRL 3-4 to TRL 5-6, such that exploration wells can be sited with greater accuracy. A multidisciplinary geothermal exploration approach, based on state-of-the-art scientific methods and integrated in industry workflows, has been key to advancement. To this end, IMAGE developed a range of exploration and assessment methods for critical exploration parameters in geothermal reservoirs (e.g. temperature, flow rate, sustainability of flow) using an interdisciplinary and integrated approach based on three general pillars:
• Understanding the processes and properties that control the spatial distribution of critical exploration parameters at different scales
• Radically improving well established exploration techniques for imaging, detection and testing of novel geological, geophysical and geochemical methods to provide reliable information on critical subsurface exploration parameters
• Field integration to demonstrate the added value of an integrated and multidisciplinary approach for site characterization and well siting.

The methods have been tested extensively and validated at new and existing geothermal sites owned by the industry partners, both in high temperature magmatic, including supercritical, and in basement/deep sedimentary systems. Application of the methods as part of exploration in newly developed fields provides a means of direct transfer from the research to the demonstration stage.
A number of tests have been performed at existing sites (brown field) where the reservoir was already sited or targeted structures and parameters already known from other sources. This allowed to validate the novel techniques. Subsequently the methods have been applied to new sites (green fields) and used to complement ongoing exploration activity.
Tests have been performed in Iceland and Italy for magmatic settings in well-known subsurface structures, whereas tests in basement/sedimentary settings benefitted largely from existing wells and data available from oil and gas exploration and production.

The achievements of IMAGE are summarized as:
• >20 novel geological, geochemical and geophysical exploration methods and techniques, of high relevance to industrial workflows;
• >5 best practice documents, catalogues and databases to be used for guidance in exploration workflows and constraints for models;
• >200 publications in peer reviewed journals (>20) and conference proceedings;
• >50 reported deliverables;
Project Context and Objectives:
In November 2013, the four year project IMAGE (Integrated Methods for Advanced Geothermal Exploration) has been launched, harnessing research power of key research institutes in Europe and industrial players to develop novel exploration techniques for geothermal power.

The rationale behind the IMAGE project is the application of cutting edge research based on a solid understanding of the subsurface processes and properties to significantly enhance the potential of geothermal energy in the energy mix. The uncertainty about the resource at depth, however, has been defined as one of the main bottlenecks for a more widespread use of geothermal energy. For the various countries without magmatic resources, geothermal power production from basement and sedimentary contexts is a valuable local source of energy, produced near the consumers who may also be interested in the co-produced heat. In addition, resources with a lower temperature can now be valorised with a better energy efficiency than before, thanks to the improvement of binary cycles.
Main targets for an extended resource base are:
• Fracture dominated fluid pathways with no surface manifestations.
• Hot systems with insufficient natural permeability suitable for the development of reliable Enhanced Geothermal Systems (EGS).
• Very high temperature (400°C) “supercritical” geothermal systems marked by much higher subsurface pressure, which can result in a significant increase of geothermal development in magmatic areas. No supercritical system has been successfully explored until today.

The barriers in the utilization of these resources are primarily connected to the financial risk of drilling a non-exploitable well. The risk for such a failure is related to pre-drill uncertainty.
The objective is to develop new methods to scrutinize and appraise geothermal systems in such a way that exploration wells can be sited with greater accuracy than before, thereby maximizing the success rate and reducing the cost of drilling associated with geothermal projects. In addition, such precision wells would reduce any potential environmental impact.

The IMAGE project will develop a reliable science based exploration and assessment method to “IMAGE” geothermal reservoirs using an interdisciplinary approach based on three general pillars:
1. Understanding the processes and properties that control the spatial distribution of critical exploration parameters at European to local scales. The focus will be on the prediction of temperatures, in-situ stresses, fracture permeability and hazards, which can be deduced from field analogues, public datasets, predictive models and remote constraints. It provides rock property catalogues for 2 and 3.
2. Radically improving well established exploration techniques for imaging, detection and testing of novel geological, geophysical and geochemical methods to provide reliable information on critical subsurface exploration parameters. Methods include: a. Geophysical techniques such as ambient seismic noise correlation and magnetotellurics with improved noise filtering, b. Fibre-optic down-hole logging tools to assess subsurface structure, temperature and physical rock properties, c. The development of new tracers and geothermometers for very high temperatures and supercritical conditions.
3. Demonstration of the added value of an integrated and multidisciplinary approach for site characterization and well-siting, based on conceptual advances, improved models/parameters and exploration techniques developed in 1 and 2. Further, it provides recommendations for a standardized European protocol for resource assessment and supporting models.

New research methods will be tested in well-known geothermal systems, both in continental sedimentary systems in Europe and in high-temperature systems related to volcanism where one might expect supercritical fluids, as in magmatic areas, such as in Iceland and Italy.
Project Results:
The achievements of IMAGE are summarized as:
• >20 novel geological, geochemical and geophysical exploration methods and techniques, of high relevance to industrial workflows;
• >5 best practice documents, catalogues and databases to be used for guidance in exploration workflows and constraints for models;
• >200 publications in peer reviewed journals (>20) and conference proceedings;
• >50 reported deliverables;

IMAGE results have been achieved three pillars
• Processes and parameters (WP3 – magmatic /WP6 – basement-sedimentary)
• Exploration techniques (WP4– magmatic /WP7– basement-sedimentary)
• Field integration (WP5– magmatic /WP8– basement-sedimentary)

Understanding processes and parameters (WP3 magmatic / WP6 - basement sedimentary):
WP3: analogue magmatic sites have been studied in Iceland and Italy, over 100m of cores, over 75 samples have been collected to measure physical properties for exploration techniques of supercritical systems, over 700 structural data have been collected in Iceland. Extensive field work has been performed in Elba island in Italy. First results for both areas indicate a strong structural control on magma emplacement and delineation of geothermal prospectivity. Autoclave experiments has shed light on relevant rock/fluid interactions at geological timescales affecting prospectivity for supercritical systems. The measurement of geo-mechanical, electrical and hydraulic properties has been successfully completed, providing key novel insights.
WP6: IMAGE developed an outline of reference physics-based models, and properties, boundary conditions at EU scale for temperature, stress and seismogenic characterization, in conjunction with required (supplementations in) data constraints and properties to improve the robustness of explorative models, and a set of catalogues to populate models with correct parameters. To this end, a rock property database and template property methods have been developed. Regional (geological) models have been made of the Molasse Basin, Rhine Graben and Netherlands areas. European reference catalogues for geothermal temperature and stress have been completed.

Exploration techniques (WP4 magmatic / WP7 – basement sedimentary):
WP4 : An extensive passive seismic network has been laid out in and surrounding the Reykjanes area, including Ocean Bottom Seismometers and is operational from April 2014. Data analysis shed light on deep structure of the Reykjanes area, of significant value for IDDP-2. A VSP survey has been performed and processed.
The apparatus for measuring temperatures larger than 380°C using synthetic fluid inclusion was completed and new data has been acquired in Iceland.
Deep electrical resistivity distribution was measured in Larderello by a new MT survey and a novel DC electric methodology named Surface-boreHole Deep Electrical Resistivity Tomography (SHDERT). Crustal stress and fracture permeability has been assessed through integrated studies.
WP7: Active seismic processing techniques for geothermal exploration and scope for adaption has been reported. A passive seismic acquisition has been performed in basement sedimentary environments. A CSEM test has been performed in Litoměřice test site.

Field Integration (WP5 magmatic / WP8 – basement sedimentary):
WP5: Analogue models demonstrate that-dipping annular reverse faults typically occur near the edge of the magma intrusions and are most likely pathways for mineral-bearing hydrothermal fluids sourced from shallow magma intrusions. Integrative local models and conceptual models for (supercritical) magmatic systems have been developed for Krafla (Iceland), Larderello (Italy) and Pico Alto (Azores, Portugal). A Supercritical resource database has been developed for Europe, and IMAGE contributed to the successful supercritical well design in Reykjanes. MT-inversion methods have been developed and tested for various sites allowing for external constraints based on complementary information. Furthermore best practice workflows have been developed for the integrated workflows in magmatic systems.
WP8: Local models have been developed for the Rhine Graben, and the Netherlands. Promising novel exploration methods developed in IMAGE such as passive seismic and reprocessing . Integrated models have been integrated in geothermal exploration in the Rhine Graben and Netherlands. In addition, coupled model approaches and combination and integration of both explorative and model techniques has been adopted to enhance explorative approaches. A best practice recommendation for the exploration workflow in basement-sedimentary settings has been developed.
Potential Impact:
IMAGE was the framework for testing more than 20 novel geological, geochemical and geophysical exploration methods and techniques of direct relevance to industry workflows. More than 5 best practice documents, catalogues and databases were produced for guidance in exploration workflows and as constraints for models. More than 200 publications have been generated in peer reviewed journals and conference proceedings, more than 50 deliverables were reported. Furthermore, IMAGE has contributed to the geothermal knowledge network between universities, knowledge organizations, and geothermal industry.

A large number of methods and technologies of IMAGE have shown their practical value in industry workflows such as new processing techniques of vintage seismic in the Bavaria Basin, Controlled Source Electro Magnetic (CSEM) studies, Surface-to-Hole Deep Electrical Tomography (SHDERT), VSP studies in Iceland and continental Europe. On the other hand, many technologies need to be further developed, but have great potential such as time lapse passive seismic.

IMAGE demonstrates rapid and radical advances, including borehole fibre-optic, passive seismic and resistivity imaging and modelling at high temperature conditions. These have been dedicated to the major challenges at hand in geothermal exploration, with major breakthroughs in a relative short time span of four years.
IMAGE allowed to implement a reliable workflow at different scales to help industries in their choices for deep geothermal exploration. This workflow developed for basement/sedimentary contexts can be applied for supercritical reservoirs and faraway magmatic fields. This includes a robust geomodel as starting point based on geological and geophysical data. This static model representing the geological structures is the skeleton of the physical and dynamic models, like thermal, mechanical and groundwater flow models, which help industries to determine the location of hidden deep reservoirs.
IMAGE contributed significantly to exploration success in IDDP-2 in Iceland, encountering supercritical fluids, and to the drilling and monitoring design of the DESCRAMBLE project, which is going to demonstrate its efficacy, as well providing key technological and conceptual breakthroughs for understanding the distribution of deep geothermal resources and prospectivity in basement/sedimentary settings such as in the Rhine Graben, Molasse Basin and in the Netherlands. For example, the results of IMAGE in the Netherlands have been instrumental for the initiative to a public private partnership for Ultra Deep Geothermal exploration (4- 8km depth) including 7 industrial consortia with a budget €28 million.
The development of exploration technologies does not end with IMAGE. On the contrary, the development of geothermal exploration for the extended resource base is at an embryonic stage. Enabling technologies are marked by a rapid grow path. Think of growing capabilities of sensor and data collection technologies (e.g. fibre-optics, wireless and remote sensing data collection), processing power and deep learning algorithms extracting relevant information.
Particularly important for further development is to work together in multidisciplinary science and industry teams with the challenges at hand. This role model of IMAGE has been successfully prolonged in the H2020 GEMex, DEEPEGS and DESCRAMBLE projects, and will most likely see further follow up in future funding by the EU.
Dissemination of data, reference models, concepts and methods has been facilitated by dedicated industrial workshops engaging end-users and stakeholders, as well as a mid-term and final conference. Furthermore, IMAGE has contributed to the geothermal knowledge network between universities, knowledge organizations, and geothermal industry.
In addition, the IMAGE website, including all newsletters public, deliverables and in particular Deliverable 2.05 presenting the main achievements in an easy accessible and informative format, forms a key portal for exploitation of key results of IMAGE.
List of Websites:
The public website address is: www.image-fp7.eu
After 2017.12.31 the website address will change to: www.image-fp7.fr