To establish a sequence stratigraphy in lacustrine rift basin: A 3D seismic case study from paleogene Baxian Sag in Bohai Bay Basin, China

摘要

The varied range usually corresponds to different levels of sequence boundaries in the lacustrine basin. The correspondence between the unconformity of the Paleogene and the sequence boundaries are studied in this article, based on an integrated analysis of 3D seismic reflections, wire logs and cores. Fifteen third-order sequence boundaries are identified and the Paleogene of Baxian sag can be divided into one first-order sequence, 3 s-order sequences and fourteen third-order sequences. Four types of sequence architectures are identified: fault slope break type, fault bench-slope break type, weak fault slope-bend slope type, fault steep slope-gentle slope type. We try to set ideas and processes suitable for the study of the sequence of lacustrine rift basins. It is believed that the sequence boundaries and orders in the continental fault lacustrine basin are comprehensive responses to tectonic activities and time. The tectonic activity is not only the main contributor to the accommodation, but also control the difference of spatial and temporal inheritance characteristics and fault spatial combination, thus controlling the combination of the depositional systems under the sequence frame and adjust the spatial dispersion characteristics of the sediment. Therefore, the sequence stratigraphic units of the lacustrine rift basin are highly consistent with tectonic evolution, stratigraphic and sedimentary cycles.