Depositional System of Submarine Fan of Well LW3-1-1, Zhujiang Formation

LW3-1-1 located in Baiyun sag of Zhujiang River mouth basin is a potential area for oil and gas submarine Fan based on a detailed study of petrologic and paleontological assemblage characteristics. The fan have developed granular flow, sandy debris flow, low -density turbidity flow and other gravity currents along the slope. Sandy debris flow is the mainly sedimentary type of channel sand bodies of the deepwater fans, and there are also reverse grading, positive grading, parallel bedding and horizontal bedding. In addition, many liquefaction and fluidization structures and biological escape trace in graded bedding as well as abundant burrow pores and bioturbation in horizontal bedding are observed. Based on analysing sedimentary facies, the depositional model of sandy grain flow-debris flow of proximal of marine turbidity fan under the background of initial transgression is proposed for the Zhujiang Formation.