To solve the prevention and control of hydrogen sulfide in the well block area, a comprehensive analysis was conducted using core samples, drilling data, logging data, well testing data, and seismic data. The quantile classification method was employed to assess the risk levels of hydrogen sulfide wells in the Bonan Sag. Using a 1:2:4:2:1 hundred-digit classification method, the study area was divided into five levels of hydrogen sulfide environmental zones, and the high-risk sulfur-containing area in the Bonan Sag was identified. Vertically, the concentration of hydrogen sulfide gradually increases with terrain from low to high. Horizontally, the source of hydrogen sulfide in the carbonate rocks of the upper Sha 4th member exhibits characteristics of “rich gypsum, rich limestone, hydrocarbon generation, and high pressure”, representing a typical “self-generated” type of hydrogen sulfide. The sag and slope areas lack material supply, but carbonate rocks are widely distributed. The coexistence of gypsum and limestone in the southern slope zone provides reservoir space for hydrogen sulfide, while fault development creates conditions for its migration, and high-pressure sealing ensures its preservation. Medium-low risk areas are distributed between high-risk and medium-high risk zones.