DI-UMONS : Dépôt institutionnel de l’université de Mons

Recherche transversale
(titres de publication, de périodique et noms de colloque inclus)
2021-09-15 - Colloque/Présentation - communication orale - Anglais - 15 page(s)

Dupont Nicolas , Kaufmann Olivier , Baele Jean-Marc , "Delineation of inferred high-transmittivity zones in the Dinantian geothermal reservoir of Hainaut (SW Belgium)" in Geologica Belgica, 7th International Meeting, Tervuren, Belgium, 2021

  • Codes CREF : Sciences de l'ingénieur (DI2000), Prospection minière et pétrolière (DI2321), Géologie (DI1411), Ressources renouvelables et non-renouvelables (DI4383), Sciences de la terre et du cosmos (DI1400), Sondages géologiques (DI2322), Exploitation des mines et carrières (DI2320)
  • Unités de recherche UMONS : Géologie fondamentale et appliquée (F401)
  • Instituts UMONS : Institut de Recherche en Energétique (Energie)

Abstract(s) :

(Anglais) The Dinantian aquifer is currently the only reservoir used for deep geothermal applications in Belgium, especially in the Hainaut (SW Belgium). In this area, 3 deep wells drilled in the 1970-80s produce hot water (typically 67-73°C @ 100-150 m³/h) from breccia and/or dissolution levels located in the upper part of the reservoir. Despite the presumed high potential of this reservoir, the development of the resource is currently limited by significant geological uncertainties. These uncertainties are mainly related to the lack of knowledge about its structure and the heterogeneity of its properties (e.g., temperature and transmittivity). To mitigate these uncertainties, several sources of data were considered, especially 2D seismic imaging and mining maps from the coal industry. The integrated results of the Mons2012 and Hainaut2019 seismic surveys provided a crucial updated imaging of the Palaeozoic basement and its structures. Among these, an E-W synsedimentary structure including an en-echelon margin seems to accommodate most of the difference in sedimentary thickness between the northern part (cf. Saint-Ghislain) and the southern part (cf. Jeumont-Marpent) of the reservoir. The analysis of many coal mining maps contributed to highlight and to map some features linked to the dissolution and/or the migration of evaporites into the underlying Dinantian reservoir. Among these features, domes and centroclines including radial structures have been considered as linked to diapirs with various states of dissolution. Based on these results, the northern part of the Dinantian reservoir has been subdivided into several categories, in agreement with deep borehole data. These categories were defined according to the intensity of the deformations identified in the coal deposit, the presence of sinkholes and indications of halokinesis. Finally, some characteristics of the Dinantian reservoir were clarified. Its geometry has been modeled based on different hypotheses supported by deep borehole data, the structural framework derived from the interpretation of the seismic sections and the characterization of the deformation in the overlying coal deposit. The spatial distribution of high-transmittivity zones related to dissolved horizons such as breccias was mapped based on the degree of dissolution of the evaporites as suggested by both the structure of the coal measures and the spatial distribution of sinkholes.