Comparison of Numerical Methods That Predict Wellbore Cement Sheath Integrity

Abstract Wellbore leakage is a concern for abandoned oil and gas wells due to greenhouse gas emissions. The leakage mechanisms and resulting integrity are not well understood. Therefore, researchers have used analytical and numerical models to investigate wellbore integrity. An analytical solution, a finite element model without failure mechanisms, and a finite element model with failure criteria were developed and compared. The benefits and shortcomings of each model were discussed, and the different models were compared with three case study wells. The results of this work show that all three numerical models predict debonding between the cement sheath and the casing. However, including the failure criteria in the models proved to be critical in predicting correct stress distributions.