Stratigraphic Simulation of Sedimentary Basins: Concepts and Calibration (1)

Abstract

A two-dimensional stratigraphic simulation program based on semiempirical algorithms has been successfully applied to clastic, carbonate, and mixed clastic/carbonate depositional regimes. The program may be used to predict reservoir distribution, to constrain interpretations of well and seismic data, to test exploration scenarios in frontier basins, and to evaluate the fundamental controls on basin stratigraphy. Applications to seismic and well-log data sets from Main Pass (U.S. Gulf Coast), offshore Sarawak (Malaysia), and the Baltimore Canyon (U.S. East Coast) demonstrate that the program simulates stratigraphy on a basin-wide scale as well as on the scale of individual prospects. The Main Pass section is an offlapping sequence of Neogene clastics. The model simulates 17 m.y. of geologic history at a 200,000-yr resolution and reproduces gross basin geometry, major sequence boundaries, depth and location of nearshore marine sands, intervals of sediment bypass into deep water, shelf margin positions, and paleobathymetry. Three Neogene carbonate buildups of central Luconia, offshore Sarawak (Malaysia), were simulated using a sea level history optimized to reproduce the carbonate growth anatomy. The model reproduced observed seismic reflection geometries and transgressive, aggradational, progradational, retrogradational, and subaerial exposure phases. The program has also simulated Jurassic-Pleistocene basin and stratigraphic sequence geometries and mixed clastic/carbonate facies distribution along a 300-km regional dip line of the Baltimore Canyon Trough. Modeled features of interest include a progradational Middle Jurassic carbonate margin punctuated by clastic deposition during sea level lowstands and a Late Jurassic-Early Cretaceous aggradational carbonate margin culminating in the development and subsequent drowning of isolated carbonate buildups. Simulated bathymetries, facies relations, and subaerial exposure surfaces for the Early Cretaceous aggradation margin are consistent with detailed petrographic, paleontologic, and seismic stratigraphic interpretations.