Natural gas hydrate is a new type of nonpolluting unconventional energy source. Accelerating its development and utilization is of great significance for both environmental protection and energy security. Drilling plays a vital role in hydrate exploration and development, directly impacting the accuracy of stratigraphic exploration and the stability of production operations. This study employs the TOUGH+HYDRATE numerical simulator to construct a hydrate stratigraphic model. We investigate the dynamic response of a hydrate reservoir subjected to drilling conditions, focusing specifically on the influence of mud parameters (density, temperature, salinity) and hydratebearing formation properties (porosity, absolute permeability, hydrate saturation) on mud intrusion. Our findings reveal that mud intrusion in hydratebearing formations is a complex, dynamic process characterized by coupled heat and mass transfer, accompanied by phase change behavior. During horizontal well drilling, pressure transfer precedes temperature transfer, resulting in the most significant downward mud intrusion. While pressure and temperature gradients stabilize within approximately one day of intrusion, hydrate decomposition persists. Increasing mud density, temperature, and salinity demonstrably exacerbates mud intrusion. Therefore, selecting appropriate mud density and using lower temperature and salinity mud, along with kinetic inhibitors or antipolymerization agents, is essential. Conversely, elevated formation porosity and hydrate saturation lead to increased hydrate decomposition and a reduced decomposition range. In addition, absolute permeability exerts a significant influence on mud intrusion depth. Our simulations demonstrate that for absolute permeabilities of 2. 9×10-4 m2, 2. 9×10-3 m , and 2. 9×10-2 μm2, the corresponding mud intrusion depths are 0. 2 m, 0. 5 m, and 2 m, respectively.