A numerical study on the feasibility of evaluating CO₂ injection wellbore integrity through casing deformation monitoring

Abstract

Abstract Distributed sensing technologies have been increasingly used for downhole monitoring in the oil field in recent years. A casing deformation monitoring system based on distributed strain sensors has been developed and proposed for wellbore integrity monitoring. However, due to the lack of field data on casing deformation induced by various exploration and development activities, the relationship between casing deformation and wellbore integrity remains unclear. To study the feasibility of evaluating short‐term CO 2 injection wellbore integrity through casing deformation monitoring, a staged finite element analysis is conducted for an existing well in the Weyburn field to study the relationship between casing deformation and wellbore integrity during CO 2 injection. The model is generated with Hypermesh TM and the analysis is conducted with Abaqus TM . The staged finite element model applies loads and materials in multiple steps to replicate the actual drilling process. The wellbore stress, casing strain, and interface gap distance change at the surface casing shoe and production casing shoe are calculated. A parametric study is also conducted to study the effect of various parameters on CO 2 injection wellbore integrity in the Weyburn field. The result shows that the casing deformation can be correlated to the wellbore integrity by cement expansion/shrinkage through its effect on the interface gap distance change and the stress difference between wellbore components induced by CO 2 injection. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.