Abstarct: The well logging data are used in the reservoir studies in some cases. Using of the electrical well log helps to known the hydrocarbon reservoir respect to identify porosity type and estimate the electro Facies of the reservoir. The velocity deviation log baxsed on the neutron and sonic log is used to determine the types of formation porosity. The multi resolution graph baxsed clustering (MRGC) method is the one of the popular methods of the clustering due to special properties. Because, the MRGC doesn’t need to know the number of clusters or initial parameters. The Sarvak oil formation that placed in southwest of the Iran is one of the important oil field. Therefore, understanding the petrophysicsl properties of this oil reservoir is very useful. In the present study, the petrophysicsl properties of this oil reservoir are estimated by using well log data and Geolog well logging interpretation software. This property is including porosity, water saturation, lithology, types of porosity and types of electrical Facies. The results of lithological analysis using cross plot from neutron-density, neutron-sonic and sonic-density show the formation have sandstone and limestone. Also, the shale is presented in formation in form of laxyers and diffused form. More than, the results show that porosity of formation is located in interval of 2 to 15 present. Also, water saturation was estimated using Archi method that show it was located in interval of 0 to 100 percent where 100% water saturation was located in shale laxyers. The results show the formation have 15% average water saturation. On the other hand, the velocity deviation log show that porosity type was Moldic, intra fossil and intra particle type. The MRGC method was used to estimate the electro Facies using log data from density, neutron, sonic and gamma ray. The results show there are dive types of electro Facies. The results show the electro Facies number five and four have best reservoir quality respect porosity and shale volume and electro Facies number 1 and 2 have the worst reservoir quality. Therefore, the reservoir quality was changed from electro Facies number 5 to 1 from best to lowest reservoir quality.