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Data from the German Continental Deep Drilling Project (KTB, Kontinentale Tiefbohrung)

This data collection provides digital access to data and publications of the KTB (German Continental Deep Drilling Program) project. KTB was a very detailed, long-term Earth science investigation on the structure, dynamics and formation of the Central European crust in Northeastern Bavaria, Germany (Harms, Kück 2016). With geophysical sounding and ultra-deep drilling it elucidated a crustal block at the border of a micro-continental collision zones amalgamated during the Caledonian and Variscan orogenies. Major research themes were: i) the nature of geophysical structures and phenomena, ii) the crustal stress field and the brittle-ductile transition, iii) the thermal structure of the crust, iv) crustal fluids and transport processes, and v) structure and evolution of the central European Variscan basement. KTB started in 1982 with pre-site selection studies and scientific objective definition followed in 1985 by site selection studies including shallow boreholes. From 1987 to 1990 a pilot borehole of 4000 m depth was drilled and fluid tests and borehole studies were conducted. In 1990 started drilling of a so-called superdeep main borehole of 9101 m depth that was reached in 1994. Again, the final drilling phase was concluded with large-scale fluid and seismic experiments. The rocks drilled comprise metamorphic series of mafic volcanic, volcano-clastics as well as minor gabbroic to ultramafic rocks that are intercalated with leucocratic meta-sedimentary gneisses. They represent most likely a deeply subducted accretionary wedge mélange with a complex P-T-t history. The undisturbed bottom hole temperature is ~265°C. Among the outstanding results are the following: (1) A continuous profile of the complete stress tensor was obtained. (2) Several lines of evidence indicate that KTB reached the present-day brittle-ductile transition. (3) The drilled crustal segment is distinguished by large amounts of free fluids down to mid-crustal levels. (4) The role of post-orogenic brittle deformation had been grossly underestimated. (5) Steep-angle seismic reflection surveys depict the deformation pattern of the upper crust. (6) High-resolution seismic images of the crust can be obtained with a newly developed technique of true-amplitude prestack depth migration. (7) The electrical behavior of the crust is determined by secondary graphite (+/-sulfides) in shear zones. (after Emmermann und Lauterjung (1997)

Multi-method petrophysical laboratory data set for crushed carbonates and sandstone

The data set comprises petrophysical laboratory data for four carbonate rocks and one sandstone – both in solid rock and crushed state. Rock plugs and particle packings of intentionally crushed and sieved material are investigated. Thereby, eight particle size classes with a mean diameter between 0.032 and 9.66 mm are investigated. The data set includes complex electrical conductivity (from Spectral Induced Polarization – SIP), specific surface (from nitrogen adsorption) and porosity (from mercury intrusion MIP). Further analyses include e.g. particle geometry, Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), Computer Tomography (μCT), uniaxial compression strength and mineralogical composition (chemical analysis, XRD).

Anisotropic broadband spectral induced polarization (SIP) data of black shale and mudstone from the Moffat Shale Group (Ireland)

This data set includes broadband (1e-4 to 1e5 Hz) frequency-dependent, complex electrical conductivity data, which have been measured in the laboratory by means of the spectral induced polarization (SIP) method on 28 oriented black shale and mudstone samples. Porosity, density and plug images are provided as accompanying information. The rock material originates from the Moffat Shale Group sampled from two shallow boreholes in Monaghan County, Ireland. Among the plug samples, 9 oriented pairs are used to derive anisotropy information of the frequency-dependent, complex electrical conductivity. The data have been processed by means of a Debye decomposition approach. The anisotropy is then determined by utilizing the foliation dip angle assuming tilted transverse isotropic conditions.

AnyPetro - Universal parameter fitting tool for petrophysical laboratory data

AnyPetro is a Matlab-based, GUI-controlled software for adjusting the parameters of arbitrary and non-linear petrophysical models to laboratory data. A Gauss-Newton scheme is applied for the minimization of a damped least-squares objective function. Thereby the Jacobian matrix is calculated explicitely with the perturbation method. Data weighting, model parameter transformations and different regularizations are provided. The petrophysical model resp. the forward operator is introduced by the user in the form of a short text file. Example data files and forward operators as well as Matlab App and standalone installers are provided. The software tool has been developed for and successfully applied to the fitting of various petrophysical data sets (e.g. porosity, specific surface, electrical conductivity, spectral induced polarization) from fluid, unconsolidated, solid and crushed samples to non-linear, multi-parameter models (e.g. electrical CO2-water interaction, Debye Decomposition, crushed rock conductivity).

Randomized rock microstructures - Collection of raster data, properties, and finite element simulation package

This collection contains 10500 computationally generated, randomised 2D microstructures, their geometrical and electrical properties, and the Matlab software package used to calculate these properties. The two-phase microstructures (mineral matrix, pore space) represent three different pore space types (microfracture networks, intergranular pore space, oomoldic pore space) and are organised into 35 ensembles - with common modelling parameters - of 100 individual microstructure realisations each. For all realisations, several geometrical properties (percolation, total porosity, connected porosity, isolated porosity, surface area, fractal dimension) and physical properties (formation factor from electrical resistivity, electrical tortuosity) are given. The collection also includes a Matlab-based finite element simulation package derived from the FEMALY library, which can be used to compute the properties of any given 2D raster microstructure.

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