Stacking Patterns in Submarine Fan System of Linked Rifting Grabens: Insights From Integrated Numerical Stratigraphy Modelling

Abstract

Sedimentary-tectonic interactions significantly influence the development and characteristics of sediment stacking patterns and reservoir architecture in the rift basins along the northwest continental margin of Saudi Arabia. Rifting deformation and strike-slip faulting modified the paleobathymetric geometries in the basin during the mid-Miocene, which formed two step-wised linked grabens. Therefore, it is crucial to investigate the controlling factors on the development of sedimentary systems, refine the delineation of the graben fills, develop a sediment dispersal model, identify sediment sources, and characterize potential reservoirs at higher resolution for hydrocarbon exploration in this area.

In this study, we adopted an integrated methodology, which combines qualitative reservoir architecture studies and quantitative stratigraphic modelling, to characterize mid-Miocene submarine fan systems in the basin along the Northwestern continental margin of Saudi Arabia. A conceptual reservoir architecture model is first established, based on seismic and well log interpretation, and core descriptions. This model indicates that submarine fan systems developed near the highlands (the sediment source area) located in the lower and larger graben. Subsequently, the detailed internal architecture of sedimentary units is modeled by forward stratigraphic simulation. A reasonably good match between the observed thickness from seismic and lithological trends from the well data has been achieved in a calibrated model. Modeling results indicate that submarine fan systems display a stacking pattern of progradation, aggradation and retrogradation. Sediment supply and fault-controlled graben subsidence are identified as the key factors in controlling this submarine fan system. The derived high-resolution facies model described reservoir facies and provided a quantitative insight into reservoir fairway prediction and quality control in the prospect area without well control.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018