In order to explore the mechanisms of wellbore instability in fractured formations and investigate reinforcement methods, homogeneous algal limestone samples collected from surface exposures were used to investigate the effects of different fracture attributes and reinforcement materials. The results show that reinforcing rock samples with various fracture attributes results in significant differences, with fracture inclination being the primary controlling factor. Specifically, samples with 0° fractures exhibit the best reinforcement effect, while those with 60° fractures demonstrate the worst. Additionally, the roughness of the fracture surface influences the reinforcement outcome, with rougher surfaces performing better than smoother ones. Furthermore, the choice of reinforcement material also affects the reinforcement effect, with cement grout outperforming emulsions and AB adhesives. It is concluded that, during drilling operations, careful consideration of the interaction between fracture surface attributes and reinforcement materials is essential to ensure the safe and efficient progress of underground work. The findings of this study offer valuable insights for wellbore reinforcement and enhancing wellbore stability.