Structural geology and petrophysics analysis to Injection wells of Mishrif Formation in Shuaiba Dome – Zubair Oil Field

Abstract

Mishrif formation is the one of the most important reservoir in Southern – Iraq and the injection water important to support the reservoir pressure. The current study combined the interpretations of PLT, structural geology and petro-physics to understand the distribution of the injection rate for nine injection wells to the Mishrif Formation in Shuaiba Dome (or culmination) - Zubair Oil Field. PLT analysis calculated injection rate for Mishrif Formation, structural analysis included geometric and genetic analysis, whereas petrophysics analysis used open hole logs interpretation and core data for the injection wells to determine the petro-physics characteristics (especially the distribution of porosity and permeability). The current study concluded that the injection rate, porosity and permeability of Mishrif Formation distributed unequally across it. This variation is almost regular, whereas the Upper Mishrif more than Lower Mishrif, while Middle Mishrif get the least value. The thickness of Lower Mishrif more than Upper Mishrif. This may affected by a folding mechanism due to tectonic activity (reactivated basement faults and Hormuz salt structures).

Characterization of Structural Geology of Faihaa Oilfield, Southern Iraq

“…Integration between geometric and genetic analysis results referred to that the study area may be controlled by tectonic activities. These results confirmed that the study area formed by same geological conditions of surrounding oilfields [22]- [25], [27], but with less intensity. The tectonic history of the study area passed through geological periods; Cretaceous, Paleogene, and Neogene Periods, and these have significant events, as shown in (Table 3).…”

“…There is no interpretation for gravity and magnetic geophysical data of the study area, but depending on the results of adjacent Oilfields and structures within the Zubair subzone (like Nahr Umr and Zubair Oilfields) the salt structures of Hormuz salt and basement faults has been indicated [11], [13], [14]. These geophysical results are linked with the oilfields' structural pictures and folding mechanisms (bending and buckle) [23]- [25]. Therefore, the bending mechanism could be attributed to the influence of salt structure-activity of Hormuz salt and/or reactivated basement faults as vertical force, while buckling mechanism to the collision between Arabian Plate and Eurasian Plate as a parallel force.…”

“…Oilfield [23]- [25]West Qurna Oilfield [27]. The fold axis of the study area has almost 3⁰ from center to south, and for north part approximately ≈ 30⁰ for Lower Cretaceous, ≈ 45⁰ from Lower Cretaceous to Miocene, and ≈ 60⁰ for early and middle Miocene.…”