Are both related to rock characteristics and are two of the primary factors that control the movement and storage of fluids in rocks and sediments. The exploitation of petroleum is partially dependent on the properties of porosity and permeability. Porosity is the ratio of the volume of openings (voids) to the total volume of material. Porosity represents the storage capacity of the geologic material. Permeability is a measure of the ease with which fluids will flow though a porous rock, sediment or soil. Just as with porosity, the packing, shape, and sorting of granular materials control their permeability. Although a rock may be highly porous, if the voids are not interconnected, then fluids within the closed, isolated pores cannot move