Porosity estimation method by X-ray computed tomography

In X-ray computed tomography imaging, the approaches used to determine the porosity of the rock from a single computed tomography scan are based on image segmentation techniques. When these techniques are applied to the same data, different results emerge and a threshold is needed at some level of the process. Consequently, the implication is that there is an uncertainty in the porosity measurement. Because of these sensibilities, a new method, called here the grey level method, is developed avoiding the use of these techniques. Considering the computed tomography image as a surface, the volumes required in porosity estimation are obtained by means of integrating this surface with simple operations applied to the image histogram. A porosity distribution which can reflect the properties of the studied rocks is developed given the value of the estimated porosity. The method is compared to two segmentation methods and is evaluated by a conventional one. A close agreement with the conventional method is found. (c) 2005 Elsevier B.V. All rights reserved.