New Oil Discovery in Al Zahraa Brownfield Using New 3D Seismic Data, North Western Desert, Egypt

Abstract Al Zahraa oil field is located in the East Ras Qattara concession, northwest of the Kattaniya inversion, and to the south of the East Tiba basin, within the northeastern part of the Western Desert, Egypt. The new discovery is likely located within one of the existing Jurassic-Early Cretaceous basins. This paper aims to highlight this discovery in Al Zahraa brownfield that was characterized by previously developed areas and currently undergoing re-evaluation using newly acquired seismic data. Al Zahraa field is a highly structure-deformed area encompassing normal, reverse, and thrust faults due to the Kattaniya Inversion. The main producing reservoir is the Late Albian-Early Cenomanian Bahariya Formation. The field is divided into multi-compartments, with a stratigraphic element of lateral reservoir facies change, adding some risk to the trap and the reservoir presence. The production performance of the field suggests more oil in place than initially calculated. Accordingly, new high-resolution 3D seismic data was acquired using the blending seismic acquisition technique with denser source and receiver line increment compared with the legacy survey, and processed using the de-blending technique with highly dense parameters to delineate the structure and obtain high-resolution field outlines. Intensive and detailed horizons and faults interpretation and mapping were successfully employed for detecting and delineating the subtle traps of Al Zahraa oil field and hence building a new geological model that is defining more potential exploration compartments to be drilled in the future. After the high-resolution 3D seismic acquisition in this field, the old geological model has changed dramatically and showed an interesting potential in the southern part to drill an exploratory well that led to a new discovery in the area. The Al Zahraa case history demonstrated clearly how effectively new dense 3D seismic survey can be successfully exploited to detect hydrocarbons in geologically complex scenarios. The initial geological model for the brownfields derived from the legacy seismic data has limited capability to match the field production performance, suggesting to acquire an up-to-date high-resolution seismic acquisition with advanced processing techniques to unlock additional exploration potential and guidance for future development plans.