Neotectonics for the Rumaila Oilfield, Southern Iraq, Using InSAR Techniques

The Rumaila oilfield is considered one of the largest, located in southern Iraq, within the administrative borders of Basrah Governorate. Production has continued there from the last quarter of the last century until the present day. The main goal of this research is to ascertain the spatial distribution and magnitude of deformation inside the Rumaila oilfield, located in the southern region of Iraq. Additionally, the study intends to investigate the potential linkage between these deformations and their underlying causes, specifically examining the influence of both tectonic and non-tectonic factors. This is achieved by the use of remote sensing methodologies, namely using microwave satellites, to validate the existence of deformations resulting from oil production activities or other reasons. This continuous production may be accompanied by surface or subsurface deformations, such as subsidence or uplift, in some areas of the oilfield, which may be a non-tectonic factor such as human activities or tectonic factors such as salt tectonics, basement rock faults, and activities resulting from the collision of the Arabian and Eurasian plates. The method of work was done using the Sentinel-1A satellite data downloaded from the ASF (Alaska Satellite Facility) website for the time period from June 2017 to December 2022 for the ascending and descending tracks, with a number of images of 75 and 74, respectively. The processing method was carried out using the SNAP software in the Windows operating system, followed by the Linux system with the StaMPS package, which uses MATLAB as its working environment. The process gave excellent results, and three deformation areas were diagnosed for the three culminations: the first is located in the north of the oilfield within the West Qurna area, where the Euphrates River is shifting to form a U-shape in the south, and the Takhadid-Al-Qurnah fault in the north. The amount of deformation was about -23 to 6.2 mm/year for ascending and the same for descending. The second area represents the North Rumaila oilfield, located between the Euphrates River in the north and the Basrah artificial water canal toward the Hammar fault in the south. It gave a rate of deformation from -33 to 9.9 mm/year ascending and from -25 to 11 mm/year descending, and the last area is the South Rumaila oilfield, located in the south of the Hammar fault and above the Basrah-Zubair fault. The rate of deformation is about -5.7 to 4.4 for ascending and -5.5 to 4.5 for descending. It is believed from the results of this study that the subsidence occurring in the north of the Rumaila oilfield is the result of non-tectonic causes, represented by human activity. In contrast, uplifts are considered results or reactions to tectonic factors. The good results obtained with very little distortion proved that the PS-InSAR method, which is usually used in urban areas, can give fairly good results for bare areas with cover. Mostly sandy, especially in the south of the oilfield.