摘要：Diagenetic processes are very important in forming and changing of the secondary porosity. Diagenetic minerals derived from these processes, play the most important role on the porosity, permeability and size variations of porethrout among the reservoir rocks porosities. In this paper, diagenetic minerals include different types of dolomites (Rd1, Rd2, Rd3, Cd1, and Cd2), anhydrites as diverse structure and textures (nodules structure and textures of needle, radial, fibrous, crystalline, amorphous, mixed, etc.), and calcites as cement (fiber/blade, equant, and poikilotopic). Due to the presence of gas within the reservoir rocks, amount and type of porosity and permeability of the rocks also is important. In the studied area, touching-vug porosities (intergranular, intercrystalline) increase the whole porosity and improve the permeability of the reservoir rock and separated-vug porosities (such as moldic, intraparticle and vuggy) increase the whole porosity but have not a large role in the extraction of gas (permeability). In this paper, the effect of diagenetic minerals on types of porosity has been studied based on the study of thin-sections prepared from cores
关键词：Diagenetic minerals; porosity; gas reservoirs; Dalan Formation; Persian Gulf.
