Computed tomography and 3D image analysis
Computed tomography nowadays is an important, non-destructive image processing technique to achieve a 3D analysis of the structural inventory of geological bodies such as drill cores or test plugs. It helps in the identification of structural features e.g. joints, fractures, folds and bedding planes. Therefore, CT-scanning is a powerful tool in modern drill core interpretation.
We apply the software package ImageJ for processing CT-scans taken with a Siemens Somatom Emotion X-ray tomograph. The software allows for measuring linear features as well as areas and volume in individual images or image stacks. Even the creation of 3D models from image sequences and the subsequent processing to animated movies is possible.
Pore space analysis based on micro-CT
With clinical CT yet a standard technique for quality control of core samples and plugs, micro-CT is in the act of becoming an even more important tool for the G&O industry. The very high resolution of the scans in the range of µm allows for the identification of mineral grains, pore space and phases. Micro-CT-scanning facilitates the determination of rock characteristics based on image data alone; a field nowadays known as “digital rock”. In particular for the characterisation of very soft and low consolidated reservoir rocks, where standard rock testing obviously is impossible, micro-CT is an indispensable tool.
We offer pore space investigations of micro-CT-scans from reservoir rocks. Our image analysis procedure allows for the identification of (interconnected) pore space and its 3D modelling. Using an Octave script the individual elements of the 3D model (pore space, wall, matrix) are discretised and finally the flow velocity field and the permeability within the interconnected pore space are calculated using a C++ script.
For the future we plan to broaden our scope offering also the determinatiuon of rock mechanical parameters such as Young's modulus and Poisson's ratio based on micro-CT data.