Sedimentary elements, evolutions and controlling factors of the Miocene channel system: a case study of the deep-water Taranaki Basin in New Zealand

Deep-water channel systems are important petroleum reservoirs, and many have been discovered worldwide. Understanding deep-water channel sedimentary elements and evolution is helpful for deep-sea petroleum exploration and development. Based on high-resolution 3D seismic data, the Miocene channel system in the deep-water Taranaki Basin, New Zealand, was analyzed by using seismic interpretation techniques such as interlayer attribute extraction and strata slicing. The channel system was divided into five composite channels (CC-I to CC-V) according to four secondary level channel boundaries, and sedimentary elements such as channels, slump deposits, inner levees, mass transport deposits, and hemipelagic drape deposits were identified in the channel system. The morphological characteristics of several composite channels exhibited stark variances, and the overall morphology of the composite channels changed from relatively straight to highly sinuous to relatively straight. The evolution of the composite channels involved a gradual and repeated process of erosion and filling, and the composite channels could be divided into three evolutionary stages: initial erosion-filling, later erosion-filling (multistage), and channel abandonment. The middle Miocene channel system may have formed as a consequence of combined regional tectonic activity and global climatic change, and its intricate morphological alterations may have been influenced by the channel’s ability to self-regulate and gravity flow properties. When studying the sedimentary evolution of a large-scale deep-water channel system in the Taranaki Basin during the Oligocene-Miocene, which transitioned from a passive margin to plate convergence, it can be understood how tectonic activity affected the channel and can also provide a theoretical reference for the evolution of the deep-water channels in areas with similar tectonic conversion environments around the world.