Task 2.7

Strenghtening the knowledge base in geothermal energy studies

Task 2.7:Strengthening the knowledge base in geothermal energy and Aquifer/Borehole Thermal EnergyStorage (ATES/ BTES) studies

Task lead: GEUS
Partners: GTK, UKRI


This task will develop capabilities within EGT to assess Estonian geothermal potential and the possibility for heat storage, carrying out integrated interpretations and correlations of seismic and well data, 3D reservoir modelling and establishment of reliable geological models. EGT researchers will participate in lectures and training using local analogues and other data.

Action 2.7.1: Introduction to geothermal energy and aquifer thermal energy storage (ATES) in sedimentary rocks.

Training at GEUS The action will introduce the concept of geothermal energy exploitation and heat storage for shallow and middepth  reservoirs, and covers the various aspects of geothermal and ATES systems, including: planning and design considerationsforshallow (0 – 300 m) to mid-depth (300 – 3000 m) geothermal energy and heatstorage, characterisation of aquifers (aquifer rock petrological characteristics, physical properties – permeability and porosity measurements, groundwater chemical properties, pumping tests to characterise aquifer hydraulic parameters), drilling techniques, environmental considerations, reservoir management optimisation, capital cost calculations of ATES. In addition, learnings and challenges from current ATES plants in Denmark will be shared, and a visit to an active ATES facility will be arranged (ATES A/S). Two weeks will be spent at GEUS in Aarhus and one week at GEUS in Copenhagen.

Action 2.7.2: Interpretation of geophysical and petrophysical data in sedimentary deposits for geothermal and ATES systems.

Training at GEUS This action aims at providing EGT researchers an overview (1 day) of data and methods used in geothermal exploration and exploitation, and includes seismic data acquisition, inversion, and interpretation, petrophysical logging techniques, sedimentology, and (seismic &) sequence stratigraphy. This is followed by obtaining hands-on experience with the interpretation and integration of seismic and petrophysical data within sedimentary rock successions using PETREL software, in preparation for reservoir modelling workflows aiding the design of ATES systems (8 days). It will also include 5 days of fieldwork training on analogues of the Upper Oligocene – Lower Miocene succession of alternating shoreface and fluvial deposits in Denmark which are relevant for the main geothermal reservoir target in Estonia.

Action 2.7.3: Introduction to advanced reservoir modelling within siliciclastic deposits within the context of geothermal energy.

Training at GEUS Over a 12-day period, the action will include introductory lectures in reservoir geology and principles for reservoir modelling in connection to Action 2.7.2, and hands-on training constructing simple static reservoir models within PETREL on Danish siliciclastic examples. The static model will then be upscaled to a dynamic flow model, where geothermal energy extraction scenarios are simulated in order to provide estimates of reservoir temperature through time. After this course, EGT researchers will have a fundamental knowledge of reservoir modelling which can be applied within an Estonian context with support from GEUS researchers.

Action 2.7.4: Borehole thermal energy systems (BTES) in crystalline basement rocks (GTK).

This training course at GTK is designed into three blocks include the following topics: (a) BTES design considerations, thermogeological parameters (petrophysics, thermal conductivity, radiogenic heat production, geothermal heat flux and geothermal gradient), testing methods, heat supply calculation and modelling. (b) Techno-economical characteristics of successful application in Finland and abroad. (c) Overview of geothermal energy field-work and laboratory techniques such as TRT (Thermal Response Test) and DTS (Distributed Temperature Sensing) applied for geothermal characterisation of rocks and monitoring production geoenergy boreholes.

Action 2.7.5: Geological-geophysical characterisation and thermal power prospective modelling of medium deep (500– 1000 m) geothermal systems.

Researcher exchange GTK-EGT (GTK: 3 persons, EGT 1-2 persons). One month in Finland and one month in Estonia. Observations of fractured crystalline reservoirs across Finland. Comparison of the Muhos Formation (Northern Ostrobothnia, Finland) geothermal energy case study with first results from geothermal energy exploration in Estonia.

Action 2.7.6: Multilevel groundwater monitoring for optimised designing of ATES systems and the feasibility of using groundwater heat pumps in shallow urban aquifers.

Training at UKRI (Keyworth) with field visits to the Geoenergy Observatories in Glasgow and Cardiff. This 5-day training course will include an introduction to all aspects of geothermal heat pumps, together with tours of the UKGEOS observatories in Glasgow and Cardiff, where it will be possible to demonstrate the monitoring methods (FO DTS, profiling, ERT, geochemistry) and principles of heat pump performance and monitoring.