Abstract: Water injection is needed in the middle and late development stages of the fractured-vuggy reservoirs in the Halahatang oilfield. The research on self-flow water injection in China is still in its preliminary stage, lacking a complete dumpflood flow model and a development effect optimization software. Starting from the key nodes such as partial perforated water layer, perforation hole, water valve and fracture-vug complex and so on, a flow model is established for fractured-vuggy water layer—fracture-vug complex unit. The software COMSOL is used to simulate the flow of these key nodes, the flow equations of each node are coupled to establish a system-wide flow coupling model, and the numerical simulation and verification are carried out by using Eclipse. The comparative verification results show that the dumpflood numerical simulation model proposed in this paper can be used to predict the self-flow water injection volume and formation pressure variation trend of fractured-vuggy reservoirs, which could provide references for dumpflood design optimization