Base-Level Fluctuation Controls on Migration of Delta Lobes: A Case Study from the Paleogene Shahejie Formation in the Huimin Depression, Bohai Bay Basin, NE China

Sandbody distribution patterns and controls are the most important foundation for petroleum exploration development, particularly in a lacustrine basin with rapid changes sedimentary environment. To provide sedimentologists geologists around world an analogue sandstone reservoir prediction, facies of fourth member Shahejie Formation (Sha-4 Member) Huimin Depression Bohai Bay Basin were analyzed, sequence stratigraphic framework was established based on characteristics spontaneous potential logs lithology. According to findings this study, Sha-4 Member’s environment dominated by delta front shallow lake facies. Delta sandbodies discovered retrograde before prograding again throughout profile. The Member is divided into third-order (LSC1), which can be further four fourth-order sequences (MSC1 MSC4), corresponding sub-members (S4-1 S4-4). During development MSC1 MSC4 sequences, depositional scale first decreased then increased changing base level. maximum flooding surface developed within MSC3 sequence. model reveals that deltas study area exhibit self-similarity, primarily MSC1, MSC2, MSC4, whereas mudstone largely MSC3.