The boundary between stable and unstable shelf in Iraq as inferred from using ideal gravity to elevation ratio

Karadaghi

Abdullah

2020

eijs

Four hundred and seventy eight gravity base stations in Iraq were used to obtain a new local theoretical gravity equation. The obtained equation was used to construct a Bouguer anomaly map of Iraq depending on the available gravity base stations. This map was compared with the Bouguer map constructed for the same stations using the international formula (1930). Good similarity in shapes and locations of the anomaly were observed, while the gravity anomaly values in the new map were increased by about 30 mGal. The eastern zero gravity contour line of the new obtained gravity map coincides with the western boundary of the tectonic Mesopotamian zone, while the main negative gravity values coincide with the Mesopotamian area, which contains most oil fields in eastern Iraq. All negative gravity anomaly areas coincide with the deepest basement rocks (the sedimentary basins) in Iraq. The obtained results are very valuable in geological applications.

Section: The Bouguer Gravity Map Of Iraqsupporting

confidence: 84%

The Bouguer Anomaly Map of Iraq According to a New Local Theoretical Gravity Equation and Its Geological Importance

Karadaghi

Abdullah

2020

eijs

“…61, No. 11, pp: 3009-3016 3011 Tectonically, this area belongs to the Mesopotamian unstable subzone [11][12][13]. The Tertiary and Cretaceous stratigraphy columns in the study area are shown in Figures-(2) and 3…”

Section: Nassir Et Almentioning

confidence: 99%

Characteristics of the Oil Water Contact Zone of Nhar Umr and Mishrif Reservoirs in Kumait and Dujaila Oil Fields, Southern Iraq, Using Vp/Vs Ratio and Porosity Logs Data

Nassir

Al-Sharaa

2020

eijs

The detailed data of the Vp/Vs ratio and porosity logs were used to detect the Oil-Water Contact Zone (OWCZ) of Nahr Umr sandstone and Mishrif limestone reservoir formations in Kumiat (Kt) and Dujaila (Du) oil fields, southeastern Iraq. The results of OWC were confirmed using P-wave, Resistivity, and Water Saturation (Sw) logs of Kt-1 and Du-1 wells. It was found that the values of the oil-water contact zone thickness in Nahr Umr sandstone and Mishrif limestone were approximately one meter and eight meters, respectively. These results suggest that the OWCZ is possibly thicker in the carbonate rock than clastic rock formations. The thickness of OWCZ in the clastic rocks changed from one part to another, depending on several factors including mineral composition, grain size, porosity, pore shape, and fluid type.

“…This subzone runs west of Nasiriyah city in the eastern side and passing through Salman and Bussaya towns in the western side (Figure-2). Al-Banna et al [16] depends on the ratio of gravity to elevation value, which normalized to ideal ratio to obtained the zero line of complete compensation of Iraq, which represent the boundary between two different tectonic regions. This boundary line may be representing the boundary between the two platform regions.…”

Section: Review Of the Western Tectonic Boundary From Isostacy And Crmentioning

confidence: 99%

The Transition Tectonic Zone Between the Two Parts of the Platform in Iraq: A Review Study

Ali

2018

ijs

The changes of the tectonic boundary locations between the stable and unstable shelf on different version of the tectonic maps of Iraq is discussed. It is found that the location of the boundary varies due to philosophy and the type of the geological parameters. It is used the stratigraphic, geophysical, structural, geochemical, hydrological and others information in delineating the boundary. The deep crustal structures obtained by using gravity data show that the boundary shifted toward the west by about 100 km in southern Iraq. According to the review, and when taking in consideration all the geological and geophysical parameters from the lower crust to the earth surface, it is believed that the boundary is not a line but it is a tectonic crustal zone. This zone represents a transition zone between the main two regions of the platform in Iraq, and it is segmented to many subzones by transverse faults. In addition, it is believed that the data of the parameters of shallow geology confirm the eastern side of the main zone, while the lower crustal structures confirm the western side of the main zone.