Identifying the comprehensive pore structure characteristics of a rock from 3D images

Abstract

Characterization of pore structure in reservoirs plays a significant role in predicting properties of rocks and classifying the reservoirs. The focus is on determining comprehensive geometric and topological parameters of pore structure. X-ray computerized tomography scanning provides a 3D image of the pore structure. However, these images cannot directly generate pore structure parameters without numerical characterization of the images. A new method is developed to determine comprehensive geometric and topological parameters of pore structure from images. These parameters were determined by utilizing common mathematical morphology operations to segment the entire pore space into a series of space blocks of different radii, subsequently identifying these blocks as pores and throats based on the proposed morphological features of pore and throat. The parallel scheme was also studied to obtain the highest efficiency. Thereafter, the characteristics of pore structures and the performance of the method were assessed for various samples. The results were compared to the results calculated by other methods. Results showed that the method produced reliable pore structure characteristics for a wide variety of rocks. Additionally, in order to discuss whether our results can be used as the basic input data for other researches, an example about two-phase flow simulation was made and a comparison of simulation results and experimental data was made. Our results were a competent choice for other studies. Also, after proposing the detection criteria of pore and throat, the subsequent detecting procedure is without artificial adjustable parameters, making the method convenient to use. This method can comprehensively, efficiently, accurately, and conveniently characterize the pore structure based only on images.