Stratigraphy Analysis of the Nahr Umr Formation in Zubair oil field, Southern Iraq

The Nahr Umr Formation is considered one of the main reservoirs produced in southern Iraq. It important siliciclastic deposits Cretaceous sequence Iraq oilfields. Zubair oil fields ZB-190 and ZB-047 were chosen to study areas. This depends on available core cutting samples determine facies analysis, depositional environments, petrographic characteristics diagenesis processes. Based description borehole, six types distinguished Formation, resulting an intercalated sandstone shale with a thin layer siltstone. clastic part showed that composed mainly quartz arenite. Diagenesis processes affecting are two compaction cementation sedimentary environment was represented by deltaic fluvial environments. These environments appear central southwestern parts area. Sequence stratigraphy beginning boundary type (SB1) (SB2) appeared upper formation. other surfaces end deposition emergence transgressive ravinement surface (TRS) within system tract (TST)and maximum flooding (MFS) middle formation each these has lateral extension along section.