Gas hydrates have captivated extensive concentration from scholars all over the world as potential alternative energy sources. In 2017, the Guangzhou Marine Geological Survey (GMGS) carried out a successful gas hydrate production test in the Shenhu area, which was of considerable significance to the study of gas hydrates in China. Several studies describing gas chimneys as the primary vertical gas migration pathways in the Shenhu area were mainly based on two-dimensional (2D) seismic data. In this research, on the basis of high-resolution three-dimensional (3D) seismic data newly acquired in 2018, combined with well logging data acquired during the 2007 and 2015 expeditions, the contribution of gas chimneys to gas hydrate accumulation was determined. As a result, four types of gas chimneys with various top shapes were identified, and their internal seismic reflection characteristics were predominantly chaotic, acoustic blanking, and high-amplitude reflection from bottom to top. Moreover, thick hydrate layers were discovered above some of the gas chimneys. Further analyses on the hydrocarbon generation and tectono-sedimentary evolution in the Baiyun Sag indicated the evolution of gas chimneys could be divided into five stages. Furthermore, as the primary vertical gas migration pathways in the Shenhu area, gas chimneys could be sourced from the Wenchang formation and Enping formation and could pierce into the Quaternary gas hydrate reservoirs. This resulted in deep thermogenic gas directly migrating upward into the gas hydrate stability zone (GHSZ) and accumulating into thick hydrate layers on or above the top of gas chimneys.