The Loss of Primary barrier: An Integrated Approach of Downhole LeakLocation and Quantification. Case Study

摘要

Failure of the primary barrier in most cases results in observable sustained annulus pressure. For other suchcases, sustained annulus pressure may not result, and leak associated fluid movement remains confined todeeper intervals, for example as cross flows. This manuscript introduces a comprehensive approach to assess the current status of primary andsecondary barriers and, for this case of integrity loss, to quantify the downhole leaks rates. The assessmentincludes: 1. Determining individual pipe wall thickness of first two concentric metal barriers usingelectromagnetic pulse logging technique 2. Spectral Noise Logging to locate the active leaks and to verify the sealing integrity of cementbarriers 3. High Precision Temperature logging for downhole leak rate quantification utilizing temperaturemodeling The paper contains the physics of measurement, lab and field tests of the barrier assessment technologies,followed with a case study: A single string gas producer, with sustained A-annulus pressure. Additionalsurvey findings allowed the identification and quantification of a crossflow resulting from leaks.