Quantitative simulation on the retrogradational sequence stratigraphic pattern in intra-cratonic basins using physical tank experiment and numerical simulation

Abstract

A well studied intra-cratonic sedimentary sequence, the Lower Permian Shanxi Formation in the Ordos Basin, northern China, is characterized by a typical back-stepping or source-ward retrogradational stratigraphic stacking pattern and can be used to illustrate the conceptual sequence stratigraphic model developed for intra-cratonic siliciclastic sedimentary basins. Based on the basic geological parameters (initial topography, lake-level curve, and sediment supply) originated from the Lower Permian Shanxi Formation of the Ordos Basin, we simulated quantitatively and validated the source-ward retrogradational sequence stratigraphic pattern of intra-cartonic siliciclastic basin, and demonstrated the use of numerical simulation to replicate and extend a particular flume experiment. In Run 1 (SQ1) the result of numerical simulation was characterized by the fan-shaped distribution, Sequence SQ2 retrograded landwards and overlaid the deposits of Sequence SQ1 after Run 2, and Sequence SQ3 retrograded further landwards and overlaid the deposits of Sequence SQ2 after Run 3. The simulation results indicated that fan-shaped deposits of Sequences SQ1, SQ2, and SQ3 retrograded sequentially landwards. The sediment distribution of three sequences in the numerical simulation is in accordance with the deposits observed in the physical experiment. The simulated sequence stratigraphic pattern of three sequences also matches that from the geological model quite well. The proposed sequence stratigraphic pattern for the intra-cratonic basin should serve as a useful reference for the interpretation of sequence stratigraphic framework and stacking patterns, and the prediction of the distribution of potential reservoir sandbodies within such basins.