Abstract: The pore is the space in porous medium where gas and liquid can exchange materials. The porous properties are mainly controlled by the morphology of the constituent particles, which determines the permeability of the medium. Due to the special formation mechanism, the coral sand has irregular particle shape and special pore properties. In this paper, the coral sand and terrestrial quartz sand are established as the control group, and the difference mechanism of their pore properties is studied from the microscopic point of view. The essential factors of the permeability difference are compared between the two sand samples. The results show that the pore properties of the coral sand can be described comprehensively by using pore radius, pore shape factor, throat radius, throat length, coordination number and pore to throat ratio. The permeability of the coral sand is affected by the properties of porosity and the particle surface. Among which, the pore connectivity and the pore throat size have the greatest influence on the permeability, followed by the pore shape. The surface properties of particles also influence the permeability, but this effect is more obvious in the range of fine particle size.

Key words: Coral Sands, Quartz Sands, Pore, Permeability, Microscopic View