Smith, Ru1, Pete Burgess2
(1) EPT-AEN SEM TRT, Rijswijk, Netherlands
(2) SIEP (Shell), Rijswijk, Netherlands
ABSTRACT: Sequence Stratigraphy and the Deep-Water Record
External controls on reservoir architecture in deep-water settings can be separated into 1) Source controls (relative sea-level history, character of sediment supply to coastlines, storage capacity of shelves) and 2) Slope and basin topographic modifiers, including the effects of complex topography on the sequestration of sand and the locations of zones of erosion and of deposition. Changes in the nature of these controls occur across a wide range of time scales. With higher bulk sediment accumulation rates in basinal settings the higher will be the potential for stratigraphic packeting (e.g. reservoir-seal pairs or intra-reservoir compartments) resulting from variations in the source parameters.
It can be important to realize that the source controls can be very different on different segments of supply margin to a deep-water basin. For example relative sea-level lowstand on one supply margin segment can coexist laterally with relative sea-level rise on an adjacent segment (due to different subsidence/uplift histories). Such variations in supply margin history and character are particularly important in active margin, failed rift and pre-drift passive margin settings.
Although hierarchy in reservoir architecture is a widely observed phenomenon important in representing heterogeneity in reservoir models, rigid hierarchical classification schemes can not be globally applied, since actual hierarchies depend on a) variability in sediment supply histories and b) position within a branching distributary system. Here it is suggested that case-specific hierarchies are established from plots of horizontal and vertical length scales of sediment bodies observed (or inferred) in a given dataset.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.