Integrated Approach to Leak Detection Using High-Definition Electromagnetic Technology, Production Logging, and Ultrasonic Logs – A Case Study

The importance of well integrity cannot be over-emphasized due to the environmental and economic implications of the associated challenges. The integrity of oil and gas wells is of utmost significance throughout their lifecycle from drilling to abandonment. Various subsurface events could lead to the deterioration of the integrity of wells over time. Corrosion of the tubulars is a major well integrity challenge in the oil and gas industry as it causes metal losses and this in turn could lead to pressure communication/ fluid leakage across damaged zones. Hence, a comprehensive understanding of the source of leaks becomes very important in order to plan appropriate remedial actions and also to evaluate the general tubular conditions to avoid future well integrity issues. To perform such investigations, more often the companies prefer to use solutions without retrieving any completion thus making it essential to have advanced technologies that work in through-tubing logging scenarios. This work focuses on an integrated approach in the successful diagnosis of tubular leaks by combining high-definition electromagnetic technology with production log data and ultrasonic logs. The first part of the well integrity assessment was carried out without having to pull any completions as the electromagnetic tool was deployed through the tubing. The capability of the high-definition electromagnetic technology in resolving metal loss in up to five concentric strings is the first critical piece of the solution. Later production logs and ultrasonic logs were run and integrated with the electromagnetic data to provide a complete understanding of the identified leak zones. For the presented case study, the primary objective of the well integrity evaluation was to determine the leak point between the 9-5/8” and 13-3/8” casings by running through the existing completions, as pressure communication was observed on surface between the respective annuli. From the analysis of the acquired data, significant metal loss was observed in the second string (9-5/8” pipe) and this was corroborated later by the ultrasonic data and production logs. In addition, considerable metal loss was observed in the third string of pipe (13-3/8” pipe) near the 20” casing shoe (4th string) with a corresponding diagnosis observed from the acquired temperature log. The successful determination of the leak points has helped the operator plan the appropriate remedial actions to fix the annuli in communication and also the unanticipated 13-3/8” pipe damage.