Pore structure and its effect on acoustic velocity and permeability of reef-shoal carbonates in the Tarim Basin, Northwest China

Abstract

Abstract Experiment and numerical simulation are integrated to investigate the effects of pore structure on physical properties in reef-shoal carbonate samples from the Tarim Basin. The results show three correlation trends between pore structure parameters and physical properties, which closely depend on the pore structure type. The acoustic velocity of the fractured-vuggy type (Structure I) is mainly affected by porosity and pore shape, whereas the fractured and tight types (Structures II and III) are controlled by the pore connection and fractures, respectively. For permeability, the main controlling factor of Structures I and III is porosity, whereas that of Structure II is the volume fraction of fractures. From the pore structure classification, combining pore structure parameters and porosity significantly improves the predictions of acoustic velocity and permeability, confirming that pore structure classification should be prioritized and determining the main controlling factors is critical for the improvement of acoustic velocity and permeability predictions. These results allow better exploration and development of reef-shoal carbonate reservoirs using seismic and acoustic log data.