Abstract:

Strata in sedimentary basins are characterized by remarkable multistage cyclicity,due to the control of multistage base-level cycles.Sedimentary cycles in different stages have certain self-similarities.Sequence stratigraphic analysis of large delta-turbidite systems in terrestrial basins indicates that self-similarity of sedimentary cycles would result in the self-similarity of sedimentary facies and reservoir distribution of sequences in different stages.Low-level fan of turbidity genesis,formed in the lowstand system tract and associated with large-scale progradation of delta,are generally adjacent to the lower boundary of long-term base-level cycle (third-order sequence).Within the long-term cycle,turbidite fans of certain scale also occur during the early rising of medium-term base-level cycle,and are distributed along the lower boundary of medium-term cycle (fourth-order sequence).The self-similarity of sequence stratigraphy leads to the self-similarity of distribution of turbidity sand bodies and lithologic reservoirs that are associated with large scale delta sedimentary systems.

Key words: high resolution sequence, sedimentary cycle, distribution of sandbody, distribution of oil reservoirs, self-similarity