Numerical Simulation on the Dynamic Damage Evolution Law of Wellbore Bonding Interfaces During Perforating Operation

During perforation operations, high-speed jet penetration into the casing-cement sheath-formation assembly damages the bonding interfaces, resulting in fluid flow along these interfaces within the wellbore. This can compromise the wellbore seal integrity and shorten the lifespan of the oil and gas well. To address this, a numerical model was developed using fluid-solid coupling algorithms, combined with a cohesive zone damage model and the ALE algorithm. The model was employed to analyze the dynamic damage evolution of the bonding interfaces during the jet penetration process and quantify the effects of the cement sheath’s mechanical parameters (shear modulus and compressive strength) and geological stress on the axial damage length and area. The results indicate that both the casing-cement sheath and cement sheath-formation interfaces exhibit significant damage, with the former showing a larger damage area under identical mechanical conditions; as the cement sheath’s shear modulus increases, the damaged area at the casing-cement sheath interface expands, while that at the cement sheath-formation interface reduces. Conversely, an increase in the cement sheath’s compressive strength reduces the damage extent at both interfaces, as does elevated geological stress. Based on engineering cases, different cement slurry types were compared to minimize perforation-induced interface damage. This study provides theoretical and practical guidance for optimizing cement selection and assessing bonding interface integrity during perforation.