Inventory and First Assessment of Oil and Gas Wells Conversion for Geothermal Heat Recovery in France

International audienceThe repurposing of oil and gas wells for geothermal energy production and resource assessment can provide sustainable solutions to meet the objectives of renewable energy balance targeted within 2030 by the French Parliament in the "energy transition law for a green growth" promulgated in August 2015. Approximately 12 500 wells have been drilled in France since the 19th century for hydrocarbon reservoir exploration and exploitation. Most of them are closed and abandoned or nearing the end of production due to the planned end of exploitation of hydrocarbons in France by 2040. Several sustainable cases of conversion for geothermal energy production have been reported in France and abroad, demonstrating the possibility of using former wells for heat extraction from aquifers or coaxial heat exchangers. This paper presents an overview of the wells drilled in France and the methodology proposed to identify and rank them according to the a priori feasibility of open and closed loop conversion. To this purpose, wells data, geological and hydrothermal information acquired by the BRGM (geometry and dynamic aquifer properties from models) and land occupation have been cross-referenced. The quantitative overview should be followed by a detailed analysis of selected wells to assess their conversion potential for geothermal energy production (possible use at surface, well drilling and abandonment reports, hydrodynamic properties of the reservoir, technology to be implemented, etc.)

The GRETA project: the contribution of near-surface geothermal energy for the energetic self-sufficiency of Alpine regions

The Alpine regions are deeply involved in the challenge set by climate change, which is a threat for their environment and for important economic activities such as tourism. The heating and cooling of buildings account for a major share of the total primary energy consumption in Europe, and hence the energy policies should focus on this sector to achieve the greenhouse gas reduction targets set by international agreements. Geothermal heat pump is one of the least carbon-intensive technologies for the heating and cooling of buildings. It exploits the heat stored within the ground, a local renewable energy source which is widely available across the Alpine territory. Nevertheless, it has been little considered by European policies and cooperation projects. GRETA (near-surface Geothermal REsources in the Territory of the Alpine space) is a cooperation project funded by the EU INTERREG-Alpine Space program, aiming at demonstrating the potential of shallow geothermal energy and to foster its integration into energy planning instruments. It started in December 2015 and will last three years, involving 12 partners from Italy, France, Switzerland, Germany, Austria, and Slovenia. In this paper, the project is presented, along with the results of the first year of work

Interprétation de tests de réponse thermique et dimensionnement de pieux géothermiques

International audienceThis paper presents a method for the interpretation of thermal response test (TRT) suitable for pile heat exchangers. As the thermal inertia of the pile is accounted for, the method increases the prediction of fluid temperature early in the test. Besides, in case of wide piles (here 60 cm diameter), achieving a complementary TRT on a narrow borehole makes it possible to decrease the duration of investigation (from 250 h to 70 h).Une méthode d'interprétation de TRT adaptée à des pieux géothermiques est présentée. En prenant en compte l'inertie thermique du pieu, elle améliore la prédiction de la température du fluide au début du test. Par ailleurs, dans le cas d'un pieu de grand diamètre (ici 60 cm), la réalisation d'un TRT complémentaire sur un forage de petit diamètre permet de réduire grandement la durée des investigations (de 250 h à 70 h)

Innovative Methodology to Compute the Temperature Evolution of Pile Heat Exchangers

International audienceEnergy geostructures such as heat exchanger piles couple the structural role of geostructures with heat and cold supply via shallow geothermal energy. This combination makes it possible to cut down the investment costs of ground heat exchangers (GHE). Thermal dynamic simulations require numerical models of pile heat exchangers to run over a reasonable amount of time. In this perspective semi-analytical models seem interesting. The paper presents an approach to semi-analytical modeling of pile heat exchangers. This approach relies on three elements: First, correlations are established to describe the evolution of wall pipe temperature under constant heat load in presence of underground water flow. These correlations take into account the underground water flow in the vicinity of the pile, allowing the computation of the temperature evolution over both the short and long terms. Second, a resistive-capacitive (RC) circuit is developed to account for the thermal inertia of the pile concrete without having to mesh its geometry. Third, the RC circuit is combined to a heat balance over the heat carrier fluid and to correlations to compute temperature evolution in the fluid. Predictions of this semi-analytical model are compared with those of a fully-discretized finite elements model. A good agreement between both models is reached. Acquisition of in-situ data is foreseen to validate both models

Implementation of Adapted Black Box Models for the Performance Characterization of Commercial Sorption Chillers

International audienc

Deployment of 5 th Generation District Heating and Cooling grids (5GDHC) in France: two case studies in Orleans and Strasbourg metropolises

International audienceBRGM is carrying out two opportunity studies on the Metropolises of Orléans and Strasbourg for the implementation of 5 th Generation District Heating and Cooling (5GDHC) grids. In Orléans, one considers supplying the extension of an economic activity zone with the 5GDHC powered by a combination of waste heat and shallow geothermal energy. A detailed energy model is being built in TRNSYS, and preliminary results related to the consumer stations are reported in this paper. In Strasbourg, the 5GDHC will supply new residential and tertiary buildings as well as a shopping centre by using the Rhine alluvial aquifer as the main energy source

Projet SunSTONE : réseaux de chaleur solaires intelligents avec stockage intersaisonnier

National audienc

Screening for national potential for UTES

The work carried out in this task comprise a screening of the national potential for UTES in the Netherlands, Switzerland, Germany, Denmark and France. Geological, hydrogeological, geochemical, etc. (sedimentary basins, mining basins, host rock formations) have been analysed to identify and characterize locations with more favorable conditions for different types of UTES systems. In the Netherlands, the three different types of subsurface potential maps illustrate a high subsurface potential at a regional scale for HT-ATES in the Netherlands, especially in the western part of the country, where, conveniently, heat demand likewise is high (metropolitan area, greenhouses, high geothermal potential). In Switzerland a spatial multi-criteria play-fairway framework was implemented focussing on the potential of implementation of HT-ATES systems in two main geologic units: the Cenzoic sediments (target of the Bern project) and the fractured Upper Mesozoic carbonates (target of the Geneva project). Subsurface data down to 2000m in depth as well as surface constraints have been combined to produce a set of favourability maps representing different potential scenarios. In Germany focus was directed to the Ruhr-area thanks to its significant amounts of former collieries and the biggest population density in Germany. This offers a big potential to include MTES to modern low-ex-heat grids. In France the ATES potential is evaluated according to available public data, by combining subsurface data (e.g. depth of the targeted geological formation, thickness, petrophysical parameters, temperature distribution at different depth, geochemistry of waters), surface data (e.g. location of district heating and cooling networks, land occupation) and energy data (e.g. heat demand, heat demand distribution in time, excess heat sources, excess heat supply in time, geographical distribution). The results show that HT-ATES could be implemented in the Dogger carbonate reservors, therefore can play a key role in increasing the share of waste heat onto DHN In Denmark targeted geological characterization was carried out in five selected sites based on the results of a survey of interest and subsequently dialog with several interested utilities. An important criterion in this work has been to cover different geological settings in the Danish subsurface and thereby cover cases of regional relevance for a wide group of stakeholders

The GRETA project: the contribution of near-surface geothermal energy for the energetic self-sufficiency of Alpine regions

The Alpine regions are deeply involved in the challenge set by climate change, which is a threat for their environment and for important economic activities such as tourism. The heating and cooling of buildings account for a major share of the total primary energy consumption in Europe, and hence the energy policies should focus on this sector to achieve the greenhouse gas reduction targets set by international agreements. Geothermal heat pump is one of the least carbon-intensive technologies for the heating and cooling of buildings. It exploits the heat stored within the ground, a local renewable energy source which is widely available across the Alpine territory. Nevertheless, it has been little considered by European policies and cooperation projects. GRETA (near-surface Geothermal REsources in the Territory of the Alpine space) is a cooperation project funded by the EU INTERREG-Alpine Space program, aiming at demonstrating the potential of shallow geothermal energy and to foster its integration into energy planning instruments. It started in December 2015 and will last three years, involving 12 partners from Italy, France, Switzerland, Germany, Austria, and Slovenia. In this paper, the project is presented, along with the results of the first year of work

Benchmark study of simulators for thermo-hydraulic modelling of low enthalpy geothermal processes

In order to assess the thermo-hydraulic modelling capabilities of various geothermal simulators, a comparative test suite was created, consisting of a set of cases designed with conditions relevant to the low-enthalpy range of geothermal operations within the European HEATSTORE research project. In an effort to increase confidence in the usage of each simulator, the suite was used as a benchmark by a set of 10 simulators of diverse origin, formulation, and licensing characteristics: COMSOL, MARTHE, ComPASS, Nexus-CSMP++, MOOSE, SEAWATv4, CODE_BRIGHT, Tough3, PFLOTRAN, and Eclipse 100. The synthetic test cases (TCs) consist of a transient pressure test verification (TC1), a well-test comparison (TC2), a thermal transport experiment validation (TC3), and a convection onset comparison (TC4), chosen to represent well-defined subsets of the coupled physical processes acting in subsurface geothermal operations. The results from the four test cases were compared among the participants, to known analytical solutions, and to experimental measurements where applicable, to establish them as reference expectations for future studies. A basic description, problem specification, and corresponding results are presented and discussed. Most participating simulators were able to perform most tests reliably at a level of accuracy that is considered sufficient for application to modelling tasks in real geothermal projects. Significant relative deviations from the reference solutions occurred where strong, sudden (e.g. initial) gradients affected the accuracy of the numerical discretization, but also due to sub-optimal model setup caused by simulator limitations (e.g. providing an equation of state for water properties).ISSN:0375-650