An Integrated Approach for Downhole Leak Detection

Abstract Effective well integrity practices ensure the protection of people, facilities and the environment from the risk of uncontrolled release of formation fluids throughout the life cycle of a well, so petroleum engineers are always required to ensure well integrity. Part of well integrity is to make sure downhole equipment and barriers are in excellent condition. Identifying the downhole leak source of pressure communication between tubingcasing and casing-casing annuli in any well is a huge challenge for petroleum engineers. Detecting any leak at the early stage is an important key to well integrity management. Two objectives were set in this paper as follows: The first objective is to develop a method that can detect downhole leaks by utilizing only rigless data based on full interpretation and evaluation of different logs in the field: temperature, noise, and corrosion log in different scenarios. The first scenario is shut-in condition while the second scenario is in flowing condition. The flowing condition will be either after bleeding off Tubing-Casing-Annulus or Casing-Casing-Annulus. This approach was implemented in a specific operation order to ensure job success. Also, the corrosion log was run to evaluate the condition of tubing and casing separately. The second objective of this study is to compare rigless approach results with the conventional rig approach for downhole leak detection, which will be completed by statistically analyzing corrosion, temperature, and noise surveys. Moreover, guidelines were set in each step of these surveys to confirm leak occurrence. This objective was achieved through developing a method and program for leak detection. Based on the conducted temperature, noise, and corrosion surveys, the integrated approach identified the leakage zones through the developed module in this report. The obtained results from the rigless approach were almost similar to the rig approach. The only difference between both approaches is that the developed method is more accurate, compared to the rig approach, since it can identify any corrosion or leak depth, while the rig approach will identify only leak zones. The paper will discuss in details the development of this method and its successful implementation in a few selected offshore wells in the same field of the Arabian Gulf.