Elastic Properties Estimation of Carbonate Samples Using X-ray Computed Tomography Images

Abstract

Predicting the elastic properties of carbonate rocks is crucial for the oil industry. However, the standard models that estimate effective elastic properties in porous media present many limitations in carbonate rocks. One of the main possible reasons is the presence of heterogeneous pore space structures. Recently, image acquisition systems based on X-ray computed tomography have been developed and allowed describing grains and pores geometries at high resolutions. Numerical simulations can then be conducted to predict the elastic properties. In this paper, we apply a new automatic image segmentation technique based on bi-level thresholding in order to separate grains and pores. Then we assess the ability of a commonly used numerical simulation technique on sandstones, based on a static method, to estimate the elastic properties of carbonate core plug samples from a Middle East reservoir under different fluid saturation conditions. Thirty three samples were available and four of them could be used to predict elastic properties. Results show that a good agreement was found in relatively homogeneous samples whereas a mismatch was revealed for heterogeneous ones. Mismatches were due to a lack of representativity related to a partial image acquisition and to a misdetection of microporosity related to the acquisition resolution.