Offshore seismic study of the northern UAE: Implications for rifting and collision tectonics

  • Guo Yi

Student thesis: Master's Thesis

Abstract

The United Arab Emirates (UAE) lies in the north-eastern part of the Arabian Plate between the Arabian Gulf and the Gulf of Oman. The country is heavily influenced by various tectonic movements. Although the surface geology of the UAE-Oman Mountains have been mapped and studied in detail, the structure of the eastern offshore of the UAE (Gulf of Oman) is still unknown. Geophysics, especially seismic, could provide an image of the subsurface and constrain the evolution of the basin and its sedimentary fill. This study used offshore seismic reflection data recently acquired in the northern UAE to determine the structure and sedimentation of this area. Nine 2D offshore seismic reflection lines of total length of almost 400 km were fully processed using SeisSpace ProMAX software. After carefully planning and testing the processing flow and processing parameters seismic interferences, multiples and other noises were attenuated. Seismic interferences were attenuated by transforming the seismic data into receiver domain. The multiples were attenuated using combination of Surface Related Multiple Elimination (SRME), predictive deconvolution in tau-p domain, and parabolic Radon transform. Both Post-stack Kirchhoff Time Migration and Pre-stack Kirchhoff Time Migration results were generated. However, the Pre-stack Kirchhoff Time Migration stacks were used to perform interpretation of the data. In this study, a new sedimentary basin in the eastern offshore of the UAE has been found. The basin generally deepens to the east, with interpreted basement reaching depths up to 3 seconds (TWT). This basin is thought to be mainly Tertiary in age and hence post-ophiolite obduction. This study also identified and described newly recognized high angle normal faults that may correspond to an uplift event in the UAE-Oman Mountains. These faults may be also related to far fields tensional stress associated with the subduction of the Arabian Plate under the Eurasian Plate. However, both the uplift event in the UAE-Oman Mountains and the subduction are caused by the continental-continental collision between the Arabian Plate and the Eurasian Plate. The basement structures of the basin are strongly controlled by normal faults and a number of these normal faults are associated with localized sedimentary depocentres. Furthermore, seismic stratigraphic interpretation of seismic reflection data was used to characterize the tectonic and sedimentary evolution of the basin. Four significant sequence stratigraphic boundaries and five distinct sedimentary packages were identified. These packages become progressively more pronounced and thicker towards the east. In addition, a series of very high-amplitude reflections were recognized throughout the seismic data, generally beneath the interpreted basement. These reflections may be related to fragments of ophiolite or hydrocarbons. Nevertheless, the aforementioned basin, Tertiary sediments and the possible ophiolite fragments are all overlying on the rifted continental margin, which laid the base structure for the later tectonic settings.
Date of Award2016
Original languageAmerican English
SupervisorMohammed Ali (Supervisor)

Keywords

  • Applied sciences
  • Collision tectonics
  • Ophiolite
  • Sediment thickness
  • Seismic stratigraphy
  • Petroleum engineering
  • 0765:Petroleum engineering

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