Perpustakaan Digital ITB

The cement sheath is a vital component in maintaining well integrity. Failure of the cement sheath can occur in various forms, one of which is the formation of voids. Voids create zones of geometric discontinuity within the system that affect load transfer mechanisms, stress distribution, and stress concentration. This study aims to evaluate the effect of the presence of initial defects and their variations in the system, namely voids, on crack propagation in the cement sheath, as well as the influence of local conditions on the surrounding local points during the loading process. The evaluation was conducted through finite element simulations of a casing-cementformation model using nonlinear static numerical analysis with four variations of cement conditions, namely 100%, 80%, 60%, and 500/0filled coverage. The results show that under the final loading condition, the 100% quadrant had a local propagation value of 4.195 in, the 80% quadrant had 4. 641 in, the 60% quadrant had 4. 672 in, and the 50% quadrant had 4.863 in along the circumference. The influence of local conditions on the surrounding areas showed a stable trend in which propagation in each quadrant predominantly tended toward the quadrant with a lower coverage percentage. This study provides an understanding of the influence of cement sheath nonuniformity on its mechanical response as part of well integrity evaluation during injection loading operations.