Application of wave impedance inversion to organic-rich rocks in Zhu III depression, Pearl River Mouth Basin, South China Sea

Wave impedance is widely applied in hydrocarbon seismic research, whereas integrated geophysical–geochemical understanding of organic-rich rocks remains insufficient for marginal marine basins. This study conducts a typical geological case investigation in the Pearl River Mouth Basin, using 48 core samples from ten wells and 3D seismic data. Geochemical analyses reveal favorable hydrocarbon generation potential, mature thermal evolution, and strong heterogeneity controlled by sedimentary facies in target source rocks. With well-log constraints, wave impedance data assist in characterizing the spatial distribution of organic-rich rock thickness and regional TOC variation across different sags. It clarifies the geochemical heterogeneity and source-rock distribution of the Pearl River Mouth Basin, demonstrates how core geochemical results can be reasonably extended to the regional scale via seismic constraints, and provides robust geological evidence for future hydrocarbon resource evaluation and strategic exploration deployment in this petroliferous basin.