Porosity and permeability of carbonate rocks are controlled by (1) sedimentation conditions, which determine primary textural features, and (2) secondary postsedimentation processes. Bioclastic carbonates, with small amounts of cement and without any appreciable amounts of secondary minerals, form the best carbonate reservoir rocks.

Postsedimentation processes appreciably alter the primary textures and thus affect the reservoir rock properties. Such processes as solution and formation of fractures and stylolites considerably improve porosity and permeability of carbonate rocks. Processes of sulfatization, calcitization, and silicification, resulting in filling and sealing of pores, cavities, and fractures, adversely affect reservoir properties.

Processes of secondary mineral formation, however, indirectly improve the flow capacity of rocks by creating heterogeneous texture, which favors the formation of fractures and solution cavities. The development of carbonate rock porosity is very complex because of the alteration by solution and secondary mineral-formation processes.

Porosity and permeability of carbonate reservoirs were found to be related closely, with the correlation factor ranging from 0.7 to 0.8.