An experimental investigation was implemented to explore the mechanical parameters of the Odenwald reservoir granitoids. The specimen within this research project was the Odenwald Granodiorite (ODG) which was extracted from the quarry on Bergstrasse in Heppenheim, Germany. The study enfolds fundamental mechanical features from intact cylindrical rock specimens.
The ODG was extracted from an active quarry and the extracted blocks were drilled into cylindrical samples. Thereafter, the samples were operated on the Mechanical Testing System (MTS) from the GFZ in Potsdam. This offers the possibility to test the rock strength, including tensile and compressive strength values, of different kind of rock materials.
Fundamental mechanical analysis including Brazilian Disk Test (BD), Uniaxial Compressive Strength Test (UCS) and Triaxial Compression Strength Test (Triax) were part of this experimental investigation. Firstly, the BD was executed to achieve the tensile strength (T0) at different loading rates (0.001 mm/s and 0.0003 mm/s) as well as the fracture toughness mode I (KIC) after Guo from 1993. These samples have a size of 50 mm in diameter and 25 mm in length. Secondly, the UCS resulted in the Poisson’s ratio (ѵ), the static Young’s modulus (E) and the maximum uniaxial compressive strength (Co). Thirdly, the Triax was done under saturated and dry conditions. Hereby, the maximum compressive strength (σ1), the compressibility (C) and the Biot coefficient were calculated from raw data. The Triax experiments have four different setups. Three different confining pressure were executed at different specimens, 20 MPa, 40 MPa and 60 MPa. Additionally, a multiple failure test was executed including all three confining pressure steps. Both experimental setups, UCS and Triax, have samples of the size of 50 mm in diameter and 100 mm in length. All these samples were dried at 60°C for at least 24h and only some Triax experiments were done under saturated conditions.
The data publication includes the raw data files from the experiment as well as files with calculated results for the above mentioned different mechanical parameters. These files are either given as DAT files or Microsoft Excel sheets summarized in a Zip folder. For further details, the full description of the data and methods is provided in the data description file. The samples used in this data publication are assigned with International Generic Sample Numbers (IGSN). These IGSN numbers can be resolved with https://igsn.org/[igsn_number] and link to the sample description in the internet.
Hydrocarbon or groundwater production from sandstone reservoirs can result in surface subsidence and induced seismicity. Subsidence results from combined elastic and inelastic compaction of the reservoir due to a change in the effective stress state upon fluid extraction. The magnitude of elastic compaction can be accurately described using poroelasticity theory. However inelastic or time-dependent compaction is poorly constrained. We use sandstones recovered by the field operator (NAM) from the Slochteren gas reservoir (Groningen, NE Netherlands) to study the importance of elastic versus inelastic deformation processes upon simulated pore pressure depletion. We conducted conventional triaxial tests under true in-situ conditions of pressure and temperature. To investigate the effect of applied differential stress (σ1 – σ3 = 0 - 50 MPa) and initial sample porosity (φi = 12 – 25%) on instantaneous and time-dependent inelastic deformation, we imposed multiple stages of axial loading and relaxation.The obtained data include:1) Mechanical data obtained in conventional triaxial compression experiments performed on reservoir sandstone. In these experiments, we imposed multiple stages of active loading, each followed by 24 hours of stress relaxation.2) Microstructural data obtained on undeformed and deformed samples.