The Role of Fault Interaction and Linkage in Controlling Synrift Stratigraphic Sequences: Late Jurassic, Statfjord East Area, Northern North Sea1

Abstract

Examination of well-constrained three-dimensional seismic data demonstrates the role of fault interaction and linkage in controlling the nature of synrift sequences on the hanging wall of the Statfjord East fault, a typical Late Jurassic structure in the northern North Sea Brent province. Al though now a single fault, the Statfjord East fault originally consisted of several en echelon segments, each of which defined individual subbasins. Structural and stratigraphic evidence, both along and across fault strike, indicates that the fault resulted from segment propagation, interaction, and linkage. Facies architecture, thickness variations, and the internal character of synrift formations are temporally and spatially related to the subbasin geometry. Variations in displacement along the fault segments exhibit characteristics of interacting en echelon faults, including anomalous displacement gradients in regions of segment overlap. We attribute the observed shifts in depocenters to local enhancement of displacement rates, resulting from the interaction of neighboring fault segments. The results have far-reaching consequences for synrift plays in the northern North Sea because they imply that only from the perspective of fault growth and linkage can the Late Jurassic structure and stratigraphy be fully understood.