Structure Trap Characterization in the Eastern Arabian Basin

Mesbah H. Khalil* and Mohammed J. Al-Mahmoud
Saudi Aramco
*[email protected]

Basement fabric and stress phase are interpreted to be the main factors controlling location, size and orientation of structural traps in the eastern Arabian Basin. Surface and subsurface investigations supported with 2-D and 3-D seismic, gravity, magnetic and satellite images in selected areas were used to achieve this interpretation. This study unraveled a wide range of diversified structures; compressional, extensional and strike-slip-related. Major north-south and east-west faults, and their related folds, represent the main hydrocarbon trap styles in the eastern Arabian Basin. These major structures are associated with smaller structures including north-south reverse faults, E-W strike-slip faults, and en-echelon E-W faults and folds. Other associated structures that were observed in the surface, and possibly exist in the subsurface, include folds related to releasing and restraining fault bends, tight detachment folds and key-stone grabens. The basement fabric, that controlled the location, size, and orientation of the structural traps, was established during the late Neoproterozoic compressional phase during the accretion of the Arabian Plate. The hydrocarbon structural traps were formed through two major compressional phases. The first phase spanned from Late Devonian to Mid-Permian. Some structural traps were developed over the pre-Devonian reservoirs. The second phase spanned from the Late Mesozoic to Recent. The majority of the structural traps were formed during this phase primarily through the reactivation along the structures that were formed in the first phase. Also, in the second phase, all structural traps were rotated eastward in response to the tilting of the Arabian Plate due to thermal uplifting of its western part.

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain