Triaxial compression test accompanied by ultrasonic and permeability measurements
A specimen of the low permeability and low porosity Dethlingen Sandstone (k: 0.04 mD, φ: 4.5%) was exposed to a low confining pressure of 10 MPa and a peak axial stress of 250 MPa. The test run is displayed in the graph below. While the stress-strain curve (in green) still takes an apparently linear course, the shear wave velocity (red crosses) is the first to exceed a maximum and subsequently slows down. This reflects the beginning of micro crack formation, and the resulting inner destruction of the sample cylinder. As soon as the micro cracks start to connect, P waves (pink triangles) also decelerate and permeability (to gas ; blue curve) increases instantaneously. From the relationship of the velocity changes between the P and S wave it can be inferred that fracturing follows the main compressive stress σ1 and that the micro cracks are oriented perpendicular to the least principle stress σ3 (for details see (Braun & Jahns 1998).
News
With the recent acquisition of the state-of-the-art DIL 502 Expedis® Select thermal dilatometer from Netzsch, we are expanding our capabilities for the precise analysis of the thermal properties of rocks and mineral materials. We are now able to determine the coefficient of thermal expansion in accordance with DIN EN 14581:2004, ASTM D4535-13e1. (2013) or using a measurement program specifically tailored to the customer’s needs (for more information, see Thermal Dilatometer).
The project, which was funded by the Free State of Thuringia, was co-financed by the European Union through the European Regional Development Fund (EFRE).
This year’s EAGE GET Conference and Exhibition is taking place in Germany:
Gesteinslabor Dr. Eberhard Jahns will again be taking part as an exhibitor this year. From 2 to 6 November 2026, you can find us at Stand 31 at the HCC in Hannover.
We would be delighted to welcome you to our stand.
Gesteinslabor Dr. Eberhard Jahns is project and research partner within the HENRI (Hydrogen Energy Reservoir) project.
Our main focus is on determining the impact of H2 on the cap rock. Besides other parameters, we measure the capillary threshold pressure using various gases and gas mixtures of hydrogen and methane.
Results were presented at the third HENRI conference in Bratislava in September 2025
We are pleased to be part of the Dutch subsurface research for geothermal heat SCAN.
Further information can be found on the official homepage:
https://scanaardwarmte.nl/english/
