Wellbore Integrity and Cement Sheath Debonding Analysis for Wells in the Eugene Island OPD, Gulf of Mexico

Abstract

The Gulf of Mexico (GoM) is home to more than 50,000 oil and gas wells with approximately 30,000 wells that are plugged and abandoned leading to concerns of oil and gas leakage where currently, little to no monitoring is performed. The cement used when completing and eventually plugging wells is subjected to harsh conditions leading to failure of the cement due to debonding of the cement to the formation and/or casing, shrinkage of the cement, and chemical degradation in the cement. The goal of this study is to identify and rank the contributing factors of stress development that influence the potential of debonding along the cement interfaces for wells in the Eugene Island OPD in the GoM using staged poro-elastic Finite Element Models (FEM). The results show that the setting stress and the pore pressure in the cement that develop during hydration cause the most potential for debonding whereas the geographic in-situ stress magnitudes and cement mechanical properties have minimal effect on the stress development.