Assessment of Wellbore Integrity of Offshore Drilling in Well Testing and Production

In this paper, a mechanical model and analysis method have been established to analyze the characteristics of casing-cement-formation of offshore wells in testing and production. The model, which can be simplified to a plane strain problem, has considered the combined actions of temperature and nonuniform in-situ stress with appropriate boundary conditions. Subsequently, the corresponding equations have been deduced to obtain the mechanical responses of the model under the two kinds of actions mentioned previously. Then, a finite-element analysis has been carried out in ABAQUS framework to verify the correctness and accuracy of the theoretical derivation. Meanwhile, the specific stress distribution and its degree of nonuniformity, as well the casing safety factor, have been obtained through a case study. On this basis, the influences of cement elastic modulus, Poisson’s ratio, casing grade, and wellbore temperature on the mechanical properties have been presented. Finally, some significant conclusions have been drawn based on the discussion mentioned previously.