The Zubair Formation is one of the major reservoirs of high production in the Rumaila oilfield, southern Iraq. The petrophysical properties analysis of the Upper Sand Member (Main Pay) of the Zubair Formation was conducted. The study includes results analysis of four wells distributed along the South Rumaila oilfield. Using a set of open well-logs, the main pay was divided into three main pay (AB, DJ and LN) units separated by two insulating shale units (C and K). The unit DJ was subdivided into three secondary reservoir units: D, F, H and the LN unit, which is split into L, M, and N. The research also includes the statistical analysis of the petrophysical properties, the calculation of the heterogeneity of the reservoir, and the cluster analysis of the upper sand member. The results indicated that the petrophysical specifications are good. Whereas, the results of the statistical analysis showed that the study wells were heterogeneous reservoirs that could be and were divided into four facies (Sand, Shaly Sand, Sandy Shale and Shale) depending on the log data.
