Abu Dhabi Structural Evolution and Its Implications for Exploration

Abstract

Abstract ADNOC and Shell are currently joining efforts to rejuvenate the exploration portfolio of Abu Dhabi. A country-wide integrated petroleum system study is being carried out to identify new play concepts and opportunities. One of the foundations of this study is the understanding of the structural evolution and its impact on prospectivity. A structural evolution model has been developed using 2D and 3D seismic data and the country has been divided into structural domains. The extent and quality of the seismic dataset provided a unique opportunity to investigate the country wide structural evolution. Special care has been taken to generate seismic attribute volumes that enhance sedimentary features and fault visualization. This allowed the detailed assessment of fault displacement. In addition, mapping of the edge of carbonate platforms through time at the country scale allowed the identification of long wavelength tilts of the Arabian plate in Abu Dhabi. These observations have been linked to the regional phases of deformations. The most important phases of deformation that affected the trap formation are the Jurassic rifting, the Late Cretaceous transtension, and mid Tertiary compression. The country has been divided into specific structural domains using existing structural features. These structural elements comprise NS and NW-SE striking basement features, forced folds associated with basement features, drape folds associated with salt domes, and NW-SE and NNW-SSE conjugate sets of transtensional faults zones associated with pop-up structures. With the help of sandbox experiment analogue models as well as field analogues from Oman, we propose that the Late Cretaceous transtensional faults are decoupled from basement and do not root into any deep basement faults. We also propose a series of conceptual 3D fracture diagrams per structural domain.