Deep-water channel system is an important part of the "Source-to-Sink" system from continental slope to deep-sea basin

and also a critical reservoir type in international deep-water petroleum exploration.The study of sedimentary characteristics

filling processes and controlling factors of the Miocene deep-water channels in Lower Congo Basin is of great help to deepen the understanding of basin dynamics and improve the prediction accuracy of deep-water reservoirs.Based on the integrated analysis of 3D seismic and logging data

we carried out in-depth study on the evolution of the Miocene high-resolution sequence stratigraphic framework

deep-water sedimentary units

types of deep-water channels

and the initiation

development

decline and extinction of channel complex systems

as well as the controlling factors in Lower Congo Basin.The technical means in terms of sequence stratigraphy

seismic stratigraphy and seismic geomorphology were resorted to in this study.The Miocene strata in the Lower Congo Basin can be divided into 14 fourth-order sequences with the maximum regression surface and the initial transgression surface serving as the sequence boundary.Among others

the fourth-order sequences SQ1L

SQ2L

SQ3L

SQ4L

SQ5L

SQ6L and SQ7L embody the major stages of deep-water channel development.Seven types of deep-water sedimentary units were identified

namely the erosional surface

channel filling

inner levee

outer levee

terminal lobe

pelagic deposit and slump block.And the channel filling and terminal lobe are arenaceous sedimentary units.The deep-water channels in the study area can be divided into four basic types

namely the single incised-channel

single aggradation channel

vertical aggradation channel complex and lateral migration channel complex.And the vertical aggradation and lateral migration channel complexes occur simultaneously in the fourth-order sequence SQ7L

indicating the controls of "autocyclicity" on channel filling processes.In conclusion

tectonic uplifting is a driving force for the formation of deep-water sand-rich channel systems

and the eustatic fluctuation in West Africa controls the development of third-order sequences and the scale of deep-water channel complex.The alternating climate change between greenhouse and icehouse controls the occurrence of deep-water arenaceous gravity flow deposits and deep-water argillaceous deposits in the fourth-order sequences.