The debonding of casing/cement or cement/formation interfaces are the representative forms of wellbore integrity failure. In this paper, a 3D finite element model for simulating the growth of fluid-driven debonding fractures along the casing/cement and cement/formation interfaces during hydraulic fracturing treatment is established. The simulation results show that (1) it is easier for the debonding fracture to extend along the casing/cement interface, (2) the fluid invasion induced debonding fractures will not cover the whole circumference of the interfaces, (3) the extent of uncovered circumferential region neighboring the debonding fracture gradually increases with the growth of the fracture height.