Coralie Aichholzer

Etudiante en thèse

PhD thesis

Subject

Stratigraphic, sedimentary and structural approach to characterize the cover-basement interface in the Rhine Graben. Application to deep geothermal energy.

Scientific field

Geology, stratigraphy, sedimentology, geothermal energy

Abstract

Since the French new pricing of geothermal energy in 2010, Alsace became the most dynamic French region regarding the realization of deep geothermal drillings at high temperatures. Several geothermal doublets are scheduled in the coming years in the Strasbourg area but also in both, northern (Outre Forêts) and southern Alsace. The achievement of the Rittershoffen’s geothermal doublet which ended in 2014, enabled the establishment of a 3 kilometers complete stratigraphic/geological section from Quaternary formations down to the top of the granitic Paleozoic basement. This geological approach was essential to the achievement of the Rittershoffen’s drillings, and will be even more for the future geothermal projects. According to the relative ignorance of the deep basin of Strasbourg, the establishment of such heat operating system requires geological knowledge, and those for several reasons:  

Firstly, it is essential to know the nature and thickness of the geological formations, both for the location of the drilling shoes and for the continuous inventory of the formations down to the granitic basement. A good compilation of the geological knowledge is one of the prerequisites for the drilling operations.

Secondly, these good knowledge of the top and base of each formations and their thickness is a particularly reliable and effective tool in determining the faults, important for fluid circulations.

Thirdly, having a coherent global view of the rocks and the formations constituting the hot water reservoir (geothermal reservoir) located in the transition “Trias-basement” are essential in the understanding of this reservoir.

Today a major new challenge appears with all the deep geothermal projects planned in the “Strasbourg Eurométropole” area (Illkirch, Eckbolsheim, Reichstett). But if most of the sedimentary cover (without faults) is relatively well known, there is still many unknowns for the Strasbourg area:

actual thickness and nature of Tertiary, which could be almost twice thicker and locally more detritic than in the well-known Rittershoffen’s drillings,

nature and intensity of fracturing in Lias, because its nature mainly clayey-marly makes it particularly difficult to define the limits of each formations,

nature and thickness of the transition “cover-basement” (granite/Permian/Triassic). Indeed, it remains poorly documented because of the great diversity of facies, both for the basement (the presence or absence of a granitic basement, or metamorphic whose nature has a direct impact on the exploitation of the heat reservoir) and for the sedimentary cover (existence or absence of the sedimentary series of the Permian and nature of these pre-Triassic formations). Moreover, nothing is known of the actual thickness of these formations, the Cronenbourg’s drilling being stopped in the intra-Permian units without any further details.

This thesis aims to study the stratigraphic column and focus on geological complexes of “cover-basement” transition and to estimate the characteristics and side extensions.

Supervisor

Philippe Duringer (Université de Strasbourg, CNRS)

Industrial supervisor

Albert Genter (ES-Géothermie)

Fundings

The thesis is co-financed as follows: half scholarship and one half from LabEx G-EAU-THERMIE (Strasbourg).

Beginning and end of the contract

October 2016 – September 2019

Scientific contributions

- Publications: 

  • Aichholzer C.,Duringer Ph., Genter A. (in prep) Gamma-ray signature of each sedimentary formation in the Upper Rhine Graben from basement to the Quaternary. Geothermics.

  • Aichholzer C., Duringer Ph., Genter A. (submitted) Detailed descriptions of the lower-middle Triassic and Permian formations using cores and gamma-rays from the EPS-1 exploration geothermal borehole (Soultz-sous-Forêts, Upper Rhine Graben, France). Geothermal Energy Journal.

  • Duringer Ph., Aichholzer C., Orciani S., Genter A. (in press) The complete lithostratigraphic section of the geothermal wells at Rittershoffen (Upper Rhine Graben, eastern France): a key for future geothermal wells. Bull. Société Géol de France.

  • Harlé P., Kushnir A.R.L., Aichholzer C., Heap M.J., Hehn R., Maurer V., Baud P., Richard A., Genter A. and Duringer Ph. (submitted) Heat flow estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks. Scopus-listed SpringerOpen Journal Geothermal Energy.

  • Aichholzer C., Duringer Ph., Orciani S., Genter A. (2016) New stratigraphic interpretation of the Soultz-sous-Forêts thirty-year-old geothermal wells calibrated on the recent one from Rittershoffen (URG, France). Geothermal Energy Journal. 4:13 DOI : 10.1186/s40517-016-0055-7

- Extended Abstracts:

Oral presentation

  • Dalmais E., Baujard C., Genter A., Hehn R., Cuenot N., Maurer V., Richard A., Glaas C., Duringer P., Aichholzer C. (2020) Feedback after drilling a new geothermal well in Illkirch (Region of Strasbourg, France). World Geothermal Congress, 25th April-4th May 2020, Reykjavik, Iceland.
  • Maurer V., Aichholzer C., Richard A., Harlé P., Hehn R., Genter A., Duringer Ph. (2018) Geothermal reservoir temperature estimation derived from gradient wells in a continental rift context (Upper Rhine Graben). 43rd Workshop on Geothermal Reservoir Engineering, 12-14 February 2018, Stanford University, California, USA.
  • Aichholzer C., Duringer Ph., Orciani S., Genter A. (2016) New stratigraphic interpretation of the Soultz-sous-Forêts geothermal wells based on Rittershoffen (URG, France). European Geothermal Congress, 19-24 September 2016, Strasbourg, France.

 

- Abstracts:

Poster presentation

  • Dunn T.E., Zachwieja A.J., Schackelford L.L., Houng N.T.M., Duringer P., Ponche J.-L., Aichholzer C., Boesch Q., Patole-Edoumba E., Bacon A.-M., Sihana D., Sichanthongtip P., Sayavongkhamdy T., Demeter F. (2019) Preliminary results from a recently discovered Holocene burial site in Northern Laos, Tam Pa Ping. American Academy of PAs, May 18-22, 2019, Denver, Colorado, USA.
  • Aichholzer C., Duringer Ph., Genter A. (2018) From the field observations to the seismic lines: focus on the understanding of the Permian-basement transition, a potential geothermal resource? 26ème Réunion des Sciences de la Terre, 22-26 October 2018, Lille, France.
  • Aichholzer C., Duringer Ph., Orciani S., Genter A. (2017) The complete chrono-lithostratigraphic log of the geothermal well of Rittershoffen, Alsace (GRT-1): an example of cuttings and field analysis in order to establishe a very precise geological log. International Meeting of Sedimentology, 10-12 October 2017, Toulouse, France.
  • Aichholzer C., Duringer Ph., Orciani S., Genter A. (2017) How to establish a very precise chrono-lithostratigraphic log based on cuttings, core samples, gamma ray logs and analogues: application on the Soultz-sous-Forêts and the Rittershoffen geothermal wells (Rhine Graben, France). Image FP-7, 4-6 October 2017, Akureyri, Iceland.
  • Aichholzer C., Duringer Ph., Orciani S., Genter A. (2017) Stratigraphic, sedimentary and structural approach to characterize the cover-basement interface in the Strasbourg area for new geothermal wells. European Geothermal PhD Days, 1-3 March 2017, Bochum, Germany. 
  • Vidal J., Genter A., Duringer Ph., Aichholzer C., Schmittbuhl J. (2014). Permeable fractures in deep Triassic sediments of the Soultz geothermal wells (Alsace, France), Deep Geothermal Days, April 10 – 11 2014, Paris, France.

Oral presentation

  • Aichholzer C., Duringer Ph., Orciani S., Genter A. (2015) New stratigraphic interpretation of the twenty-eight-year old GPK-1 geothermal well of Soultz-sous-Forêts (URG, France). 4th European Geothermal Workshop, 19-20 October 2015, University of Strasbourg, France.

- Reports

  • Aichholzer C. (2015) Chronostratigraphic well-to-well correlation from the geothermal drilling data (Soultz-sous-Forêts/Rittershoffen). Master degree 2nd year Confidential report EOST-ESG, University of Strasbourg.
  • Aichholzer C., Wolff C., Duringer Ph. (2014) The Lower Triassic and the Permian sediments in the borehole EPS-1 (Soultz-Sous-Forêts), chronostratigraphic and photography of drill cores. Confidential report EOST-ESG.
  • Aichholzer C. (2014) Importance of logging methods in the recognition of the stratigraphic limits: application of the Rittershoffen geothermal wells. Master degree first year Confidential report EOST-ESG, University of Strasbourg.

Teaching experiences

2018/2019 :

  • Staff member for tectonic and sedimentologic field courses in the French southern Alps, L3 students, 15 days

2017/2018 :

  • Tectonic and rheology, L3 students, 36h
  • Staff member for tectonic and sedimentologic field courses in the French southern Alps, L3 students, 10 days

2016/2017 :

  • Introduction to geosciences, L1 students, 12h

  • Tectonic and rheology, L3 students, 18h

  • Staff member for tectonic and sedimentologic field courses in the French southern Alps, L3 students, 10 days

  • Staff member for geological and sedimentologic fieltrip in the Vosges (Alsace, France), L3 and M1 students, several days