Well Integrity Management Based on New Operating Limits - A New Method for Extending the Well Lifespan and Changes in Operating Conditions

Abstract

Abstract This paper proposes to explore the application of new operational limits for wells under a life extension in mature fields and wells subjected to changes in production parameters caused by several factors. In this context, physical tests, and finite element analysis (FEA) were performed for a better understanding of its new engineering limits. The establishment of new operational limits was based on a meticulous study of loadings, considering their frequencies of occurrence and magnitudes. Additionally, a comprehensive evaluation of the casing and packoff strengths was conducted from a limit state design perspective. The integration of these factors resulted in the determination of the design limit. The design limit allowed for the definition of a supplementary region to the operational envelope, resulting in a significant reduction of false alarms and incident reports to the Brazilian regulatory agency. Furthermore, to ensure the accurate implementation of the new design limit, a corrosion analysis of the production casing was conducted using computational fluid dynamics (CFD). This analysis aimed to evaluate the potential consequences of tubing failure on the remaining wall thickness of the production casing. The analysis has demonstrated that in certain situations, it is crucial to ensure the tubing string remains intact to prevent the corrosion from compromising the strength of the production casing. The new implemented limits (Operational Envelope and Design Limit) were established within an integrity management system that aims to provide advanced real-time production data analysis, resulting in the continuous generation of well safety factors. Following the establishment of these concepts, a case study was conducted, demonstrating a significant reduction in the number of reports submitted to the Brazilian regulatory agency due to the definition of the design limit in addition to the operational envelope.