Facies Architecture, Diagenesis and Paleoceanography of Mishrif (Late Cretaceous) in Selected Wells of West Qurna Oil Field, Southern Iraq

Abstract

Abstract The Cretacous is consider as very substantial period especially in middle and south of Iraq inasmuch of hydrocarbon content along his rock succession. In present work, the Mishrif Formation was studied in well 220 and well 280 of West Qurna oil field, Southern Iraq, the examination of the hand specimens of the formation rocks indicates recrystallized vuggy limestone in well 220 and recrystallized limestone in well 280. Twenty-four core samples distributed equally over the two wells were collected and prepared for microscope examination. Six main types of microfacies were found in both wells, these are: lime mudstone, wackestone, packstone, grainstone, rudstone and grapestone; and four submicrofacies these are: bioclast wackestone, benthic forams wackestone, bioclast packstone and peloidal packstone. The diagenetic processes include: cementation, dolomitization, compaction, dissolution and porosity. The microfacies examination reflect facies zone (7, 8 and 9A) which indicate deposition in the (evaporitic to the open marine) platform interior environment.