By Dept of Petrophysics and Borehole Geophysics, Leibniz Institute for Applied Geophysics (LIAG) - Matthias Halisch, Cornelia Müller, Wiete Hübner and Thomas Wonik.
The department of Petrophysics and Borehole Geophysics at the Leibniz Institute for Applied Geophysics (LIAG) conducts fundamental and applied research in process-focused petrophysical characterizations of natural rocks. Besides standard petrophysical core analysis (CAL), special rock core investigations (SCAL) are carried out to understand complex petrophysical processes and to improve the assessment and characterization of porous reservoir rocks. Results are directly linked to improve recent and develop new methodologies, devices and techniques for paleo-climatic research, geochronology, general reservoir characterization, geothermal energy usage as well as CO2 sequestration and storage (CCS).
A significant strength of this department is the close linkage of in-situ measurements in boreholes with detailed and complex lab scale experiments, which greatly enhances the knowledge of physical processes on different scales.
An important part of modern petrophysical research is recently formed by numerical modeling – so called “digital rock physics” (DRP) – which is getting an increasing focus of interest. Recent developments of new and versatile imaging techniques and auspicious computational hardware have greatly increased the possibilities for complex and interdisciplinary rock characterization.
The department of Petrophysics and Borehole Geophysics uses a high resolution micro-CT (nanotom 180, from GE Sensing & Inspection Technologies – phoenix|x-ray) to derive non-destructively high quality 3D imaging data sets of conventional reservoir and highly complex porous rocks. With this compact lab scale imaging device, voxel resolutions within the sub-micron range (600 – 800 nm) are feasible. These high-resolution data sets are used for qualitative and quantitative petrophysical investigations and for numerical modeling purposes at the pore scale.
In this respect, Avizo® Fire software offers great functionality and a wide range of possibilities for visualization and complex rock sample characterization. Generally, the workflow starts with basic visualization and identification of the different mineral phases within the rock sample. Then, pore space can be segmented from this data in different ways: either by means of total porosity evaluation or by segmenting effective – i.e. interconnected – porosity only. The so-derived pore network can be further investigated to get access to even smaller scale pore space topology and geometry by using the skeletonization module of Avizo. Additionally, a variety of quantification tools allow even more complex research, e.g. the determination of small-scale porosity inhomogeneities, determination of representative elementary modeling volumes, pore space tortuosity and many more.
Once this image-based rock characterization is performed, imaging data can be prepared for numerical modeling purposes. Not only computational fluid dynamics (CFD), but also modeling of complex electrical properties and nuclear magnetic resonance effects at the pore scale can be conducted. Avizo’s “Wind” module offers a versatile toolbox for the visualization of these results, which greatly increases the knowledge of petrophysical rock properties.
About LIAG
The Leibniz Institute for Applied Geophysics (LIAG) is a federal, non-university research institute that uses methods of applied geophysics to research and solve geoscientific problems, which are addressed to the needs of the society. Focus lies in the exploration of structures and processes in the subsurface, and in the development of new methods and techniques for geophysics, geohydraulics, geothermics, and geochronology.
More information: www.liag-hannover.de
About Avizo
Avizo® software is a powerful, multifaceted tool for visualizing, manipulating, and understanding scientific and industrial data. Wherever three-dimensional data sets need to be processed, in materials science, geosciences, environmental science or engineering applications, Avizo offers abundant state-of-the-art features within an intuitive workflow and easy-to-use graphical user interface.
More information: www.avizo3d.com
Related testimonial (published Nov. 20, 2011 on VSG website)
"Visualization of pore networks and fluid flow in porous rocks", by LIAG (S5) - Matthias Halisch, Cornelia Müller, Wiete Hübner and Thomas Wonik.
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