Sedpak — A Qualitative Computer Simulation for Understanding Sequence Stratigraphy Modeling Concepts and Parameters

Moore, Phil; Kendall, Christopher G.; Viparelli, Enrica

Sedpak, a sedimentary computer simulation developed at the University of South Carolina, assumes clastic transport based on slopes and carbonate production based on water depth. Output geometries display a sequence stratigraphic framework of erosional and depositional surfaces of the simulated section. Sedpak extends interpretation of depositional setting and predictions of lithofacies geometries away from the studied areas. It aids prediction of facies likely to contain both hydrocarbon and water resources and their characteristic fabrics.

Redesign of Sedpak incorporates open source software applications and tools. New design continues to provide a platform for understanding how different geometries are produced by varying sea-level, sedimentation, and subsidence.

Computer modeling of sedimentary geometries that match interpreted sections is a repetitive exercise in parameter estimation, viewing of resulting geometries and adjusting of parameters to converge on a best match. Intuitive model parameters based on physical processes, including rates of clastic sediment accumulation and transport distance down slope in a two dimensional simulation space, offer valuable insight into a more quantitative modeling approach. Further information on the fabrics of the deposits can be obtained by means of coupling computer models of sedimentary geometries with physically based submodels that describe the spatial and temporal evolution of relatively small portions of the entire system. The origins of sediment geometries and facies are interpreted by comparison with observations of similar features in modern sedimentary systems and their processes and then the interpretations are tested with the Sedpak simulation. The question is: do input parameters match those inferred from current field observations parameters set to create basic sequences stratigraphic systems tracts, including prograding low-stand and high stand systems tracts, and retrogradational transgressive systems tracts? The same applies to in-situ carbonate accumulation. Are the depth-production rates reasonable?

Sedpak provides a work setting to tune initial conditions and model parameters producing 2-D sedimentary geometries that intuitively 'make sense' to new and experienced stratigraphic modelers. A new open source design will eliminate collaboration barriers and offer easier access to model data and depositional algorithms.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013