Sedimentary filling characteristics and the main controlling factors during the Early-Middle Miocene in the deep-water area of Shuangfengnan Slope in the northern South China Sea

Deep-water deposition on the slope has become one of the major issues in China's offshore oil and gas exploration in recent years.We studied the seismic facies of the Shuangfengnan Slope in the northern South China Sea during the Early-Middle Miocene by combining external form and inner structure based on 2D multi-channel seismic and drilling data.Four typical seismic facies were recognized, including "S" type progradational seismic facies, mound type progradational seismic facies, parallel chaotic seismic facies, and parallel seismic facies. The paleogeographic evolution of the study area and the tectonic-sedimentary evolution of its adjacent area during the same period showed that three typical sedimentary systems (shelf-margin delta, slope fans, and slump deposits) were developed under the control of relative sea level change, provenance and the tectonic movement. The delta system with sources from South China and the Pearl River is the most important factor affecting the development of slope depositional system, and is the material basis of the depositional system. Tectonic movement and relative sea level change provided accommodation for the slope sedimentary system development.