Evaluation of the Structural Framework of the Mishrif in the Area between the Garraf and Nasiriyah Oil Fields Using Multi-Scale 2D–3D Seismic Interpretation

This study assesses the structural framework of the Mishrif Formation between the Nasiriyah and Garraf oil fields in southeastern Iraq using integrated 2D and 3D post-stack seismic interpretation and well data from Ns-1. As the study area lacks drilled wells, well tops, check-shot data, sonic logs, and formation depths, well-to-seismic calibration was performed using data from the nearby Nasiriyah field. A synthetic seismogram for the Ns-1 well enabled the identification and correlation of the Top and Base Mishrif reflectors in the study area. The Top Mishrif reflector appears mainly as a zero-crossing event, while the Base Mishrif/Top Rumaila reflector is identified as a peak event. Two-Way Time, average velocity, depth, and isopach maps were developed to interpret the subsurface structure. The Two-Way Time and depth maps show structural deepening toward the east and northeast, while the isopach map indicates increased Mishrif thickness to the west and northwest. Several nose-like structural features were recognized, with the 3D model provides a clear illustration to them and may represent potential traps in the reservoir. The primary aim of the study is the combination of 2D and 3D seismic interpretation with well calibration to better explain the structural continuity, geometry, and trapping configuration of the Mishrif Formation.