Fracture identification and quantification through digital rock analysis

There are huge geological reserves of oil and gas in the eastern South China Sea, and the reservoir rocks contain a large number of micro-fractures. The fracture density, geometry and connectivity are critical in the reserve evaluation and field development. There are two types of micro-fractures, one is unfilled, and the other is filled with minerals, mud, paleo soils and other debris, or asphaltenes. In this paper, a method for segmentation and quantitatively characterization of micro-fractures based on digital rock is proposed. (1) Firstly, two-dimensional micro-fracture images are obtained by micro-CT scan; (2) Extracting two-dimensional filled and unfilled micro-fractures to obtain the segmented images; (3) Reconstruct the three-dimensional model based on the two-dimensional segmented images; (4) Quantitative calculation of the fracture density, connectivity, filled and unfilled fracture porosity and etc. Digital analysis of igneous rock samples and quantitative characterization of filled and unfilled micro-fractures can greatly improve the evaluation of fractured reservoirs, which is critical for exploration and development of such field.