Abstract: Through practices of litho-stratigraphic hydrocarbon exploration and development, the theory and technical method of seismic sedimentology can be effectively applied to build high-frequency stratigraphic frame and study the variation of depositional system in terrestrial rifted lake basin. Here, we present our study on the Wenchang formation of Paleogene strata of PY4 Sag using seismic sedimentology theory. Based on high-resolution processed seismic data and third-order sequence frame, system tract cycle is defined as a study unit. Combined with lithological data of drilled wells, six third-order sequences can be recognized, and the relationship between seismic polar and lithological attribute can be established by 90° phase-rotation, seismic slice and quantitative rock-physical technical. Key slices are chosen in SQ2 to reveal the depositional system variation of fan delta, nearshore subaqueous fan and braided river delta that prograde basinward from west and east of PY4 Sag.

Key words: Pearl River Mouth Basin, Panyu 4 Sag, seismic sedimentology, strata slicing, 90°, phase rotation