The primary type of reservoirs found in Oman is carbonate reservoirs, which can be easily altered by various processes, including diagenesis and tectonic events. These alterations can modify the original chemical composition of the reservoir by adding new ions, changing the rock fabric, and ultimately affecting the reservoir quality either positively or negatively. It is crucial to investigate and comprehend post-depositional alterations and connect them with the initial settings of the reservoir. Therefore, a study is conducted on the Mid-Cretaceous Natih Formation located in North Oman to comprehend the effect of diagenesis on the quality of the reservoir in terms of permeability and porosity. The study focused on two outcrops within Ad Dakhiliyah Government: Natih-E and D in Wadi Mu’aydin and Natih-E and A in Wadi Nakher at Al Hamara. Thirty-nine samples were collected from outcrops and sent to the lab for the core cutting process and to measure the porosity and permeability. Twenty-five samples are thin-sectioned for the petrographic study. The staining technique provides information about Fe-bearing cement and dolomite. Major, minor, and trace element analyses measure the concentration of elements such as Fe, Mn, and Sr. The common skeletal grains observed are foraminifers, algae, rudist, brachiopod, and echinoderm fragments. The microfacies comprise mudstone, wackestone, packstone, and grainstone. A majority of the thin sections are dolomitized. The results indicate that the reservoir is considered tight. The average porosity is 4%, and the permeability is 0.034 mD. Therefore, the reservoir quality is influenced by the diagenesis process (compaction or cementation). Microbial impact plays a vital role in forming full micritization, partial micritization, and micrite envelop features. Two generations of dissolution resulted in the formation of secondary porosity, such as vuggy and melodic porosities. Various types of cement can be determined. These types are isopaches, drusy, blocky, and syntaxial vi overgrowth of calcite cement. These cements act as fracture-filled and pore-filled. More than one generation of fractures is present. These fractures are filled with ferron and nonferron calcite and dolomite in some areas. The cement types have been validated using elemental analysis. The study suggests four main diagenetic process alterations influence the Natih Formation after a detailed analysis of the diagenesis features, including micritization, dolomitization, cementation, and compaction. Initially, the Natih Formation is affected by early meteoric and marine diagenesis, followed by shallow burial diagenesis, intermediate to deep burial diagenesis, and late meteoric diagenesis. Paragenesis sequences for NatihA, D, and E are constructed to reflect the impact of these diagenesis processes