Hypothesis Testing Using Fuzzy Logic Simulations to Constrain the Domains of the Stratigraphic Variables that Control Reservoir Distribution and Character

Bartek, Louis R.¹, Jeffery D. Warren² (1) University of North Carolina at Chapel Hill, Chapel Hlll, NC (2) University of North Carolina, Chapel Hill, Chapel Hill, NC

Development of continental margin stratigraphic architecture for systems with extremely wide shelf, low gradient and deep shelf edge and depositional conditions that include variable, but relatively high sediment input, variable rates and amplitudes of eustatic change, and variable rates of subsidence were simulated using Fuzzy Logic. This type of system is rare today, but mimics conditions found in ramp settings such foreland basins and other epicontinental seas, which were widespread in the past and comprise a significant component of the stratigraphic record. The output of the Stratigraphic Fuzzy Logic models is geometric. Rather than directly simulating the actual flow processes responsible for the sediment distribution, the model distributes sediments beneath profiles of equilibrium across the continental margin based on empirical or observational data to approximate the results of sedimentation as geometries, which in turn creates a stratigraphic framework of reservoirs.

This is an appropriate tool to use to delineate relationships between depositional processes, eustatic change, tectonic activity and stratal architecture (geometries) when one is attempting to understand which processes exert the most control in producing the stratigraphic architecture seen in remotely sensed data such as seismic profiles. Seismic profiles are a composite of geometries in which there is often limited insight into the role of the processes that created the geometries. When combined with seismic profiles and limited lithofacies and chronostratigraphic data from core, Fuzzy Logic simulations provide an opportunity test hypotheses about how variables exert control on the stratigraphic geometries that influence reservoir characteristics. An example of application of this approach is presented using seismic and core data from the East China Sea.