Rüdiger Giese and colleagues (including myself) published a paper in the Geological Society, London, Special Publications entitled “The CHENILLE experiment: Monitoring of fault-heating and fluid-injection in shale rocks at the underground research facility Tournemire, Southern France”. The paper presents the results of the in situ experiment we introduced in an earlier post. CHENILLE studies how high temperatures affect shear zones and fault reactivation in shale formations. In the experiment, a strike-slip fault zone exposed in IRSN’s Tournemire Underground Research Laboratory was heated in a controlled way and then subjected to fluid injection. The goal is to understand how the mechanical, hydraulic, structural, and thermal properties of the fault zone evolve under thermal and hydraulic loading. The fault was heated from November 2023 to July 2024, with the temperature in the fault core kept at or below 40°C. Two series of injection tests with gas (nitrogen and argon) and water followed in June–July and October–November 2024, targeting both the fault core and the damage zone. The injections used monotonic, cyclic, and stepwise increasing flow rate protocols adapted to the Tournemire shale. The injection periods were accompanied by a clear increase in acoustic emission activity.
Reference:
Giese, R., A. Bonnelye, C. Boese, C. Cunow, P. Dick, R. Esefelder, T. Foerster, S. Fuchs, K. Jaksch, G. Kwiatek, S. Lüth, B. Norden, K. Plenkers, H. Richter, I. Sass, S. von Specht, A. Zang, and G. Zimmermann (2026). The CHENILLE experiment: Monitoring of fault-heating and fluid-injection in shale rocks at the underground research facility Tournemire, Southern France. Geological Society, London, Special Publications XXX, doi 10.1144/gslspecpub2025-42