| Title | Production history modelling of a low enthalpy geothermal reservoir used for district heating: example of the Paris sedimentary basin |
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| Authors | J. Popineau, T. Renaud, J. OSullivan, J.G. Dorado |
| Year | 2022 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Deep sedimentary basin, geothermal modelling, district heating, production history matching, Dogger, Waiwera |
| Abstract | Exploitation of the geothermal energy in the Paris sedimentary basin started in the early 1970’s, accessing the hot brine contained in the mid Jurassic carbonate rocks series, the Dogger. More than a hundred wells have been drilled to depths ranging from 1400 to 2000 meters, often using the doublet or triplet technology. Decades of production and reinjection have resulted in variations of the aquifer pressure and temperature in some areas. The characterization of the Dogger heterogeneities and the understanding of potential interconnections between the doublets areas of influence are essential to define sustainable management plans for current and future geothermal developments. While the integration of a full-scale refined geological model into a reservoir model needs heavy computational resources, a simplified model gathering the main productive areas into one or two layers surrounded by sealed formations can be used to efficiently investigate the aquifer characteristics in a zone operating one or several doublets. Due to the high density of geothermal operations in the Paris sedimentary basin, regional numerical approaches are needed to assess potential interactions between doublets. With this aim, the modelling of 13 doublets and 1 triplet intersecting the Dogger reservoir in the South part of Paris (Cachan/Orly) is performed, using a conventional double layer approach to simulate the natural state and production history of the area with the numerical simulator Waiwera from the University of Auckland in New-Zealand. The history matching to available production data is used to capture variations of the reservoir behaviour caused by natural and anthropogenic fluid flows in the heterogeneous Dogger reservoir. The geothermal reservoir properties and the production timeline are investigated during the calibration process, which uses a robust modelling workflow and a fast simulation to handle complex production history data. Modelling a large scale geothermal field is valuable for understanding the pressure and temperature response in the productive areas, to suggest better monitoring of the geothermal resources, and to define future strategies for operating the reservoir in a sustainable way. |