Papers by Keyword: Digital Core

Abstract: Pore reflects fluid storage capacity of the rock, while the shape and size of the throat, together with the pore throat ratio, control the permeability and fluid reservoir capacity. There are mainly two aspects in microscopic pore structure characteristics evaluation at present: experiment and theoretical modeling. In this paper, several experimental methods and modeling methods that currently exist were compared and analyzed. The analysis shows that in the aspect of experiments, the domestic basic research in the field of three-dimensional pore structure model reconstruction technique is still relatively weak under limited conditions of equipment and technology, while in the aspect of models, the current domestic research is still relatively rare. A conclusion is drawn that the main problems in the study of microscopic pore structure at home are still the degree of improvement in the accuracy of the experiment and the model upgrade.

Abstract: In this paper, firstly, the X-ray micro computed tomography (micro-CT) is used for the analysis of internal structure of sand-packed beds. Binary data which are able to describe the pore structures of these beds were obtained from a series of imaging processing of rescaling, media filtering, and thresholding. Then a Maximal Ball (MB) algorithm is applied to these binary data to extract the equivalent pore networks. The parameters of the pore networks, such as radius, coordination number and shape factors of pore and throat are computed. The results demonstrate that the MB method can extract reasonable and faithful pore network of the different sand packed samples. Finally, the relative permeability and capillary pressure of drainage and imbibition cycle of water and oil are predicated. The numerical simulation results demonstrated good accordance with that of the experiments. Pore network simulation shows good results for two phase flow in porous media.

Abstract: Advances in micro-CT imaging of porous materials provide the opportunity to extract representative networks from the images. This improves the predictive capability of pore scale network models to predict multiphase flow transport properties. However, all these predictions need to be validated with laboratory experimental data. The experimental data for such validation may either be from the literature or newly conducted laboratory experiments on same outcrops. This paper presents the review of some of the available Pc – Sw experimental data available in the literature for validating the predictions made by network models.

Abstract: This paper presents comparisons between drainage capillary pressure curves computed directly from 3D micro-tomographic images (micro-CT) and laboratory measurements conducted on the same core samples. It is now possible to calculate a wide range of petrophysical and transport properties directly from micro-CT images or from equivalent network models extracted from these images. Capillary pressure is sensitive to rock microstructure and the comparisons presented are the first direct validation of image based computations. The measured data include centrifuge and mercury injection drainage capillary pressure for fired Berea, Bentheimer and Obernkirchner sandstones and unfired Mount Gambier carbonate. The measurements cover a wide range of porosities and permeabilities. The measurements were made on core samples with different diameters (2.5 cm, 1.5 cm, 1 cm and 0.5 cm) to assess the effect of up-scaling on capillary pressure measurements. The smallest diameter samples were also used to obtain the 3D micro-CT images. Good agreement was obtained between the experimental measurements and direct computations on 3D micro-CT images.