Mitigating Challenges in Resolving 7” Liner Leak- Case Study

An evaluation process was conducted in assessing various solutions towards remedial action to a 7” liner with an identified leak in a water injector well. The leak to the 7” liner was identified through pressure testing of the well. A comprehensive investigation and analysis was performed to identify the liner condition, exact leak location and the extent of the leak. It was accomplished by analyzing all previous activities performed during the life of the well and through running special pressure testing as well as logging the well with ultrasonic and physical logs. The problem identification and proposed solutions were focused on curing the leak and bringing the well back on injection with the least operational risk and highest possibility of success. Corrosion and cement bond logs were ran and showed a better picture in regards to the extent of the corroded section and the quality of cement behind it. A caliber log was also run in the open hole which showed a washed out area near the 7” liner shoe. Several solutions that could repair the 7” liner leak were assessed including: i) cement squeeze in the leak zone, ii) setting an off bottom 4.5” liner and iii) using a 5.5” expandable liner. The evaluation process included each solution’s impact on the future injectivity of the well, the effectiveness of each option, operational challenges and associated risks. Moreover, nodal analysis was performed to evaluate possible reduction of the injection rate associated with each solution. The final decision to repair the leak was to run an expandable liner and it was based on its advantages and deployment challenges. Lessons learned from this operation included the methods used to identify and assess the damage of the casing leak. Proper preparation and cleanout of the corroded section and the operation procedures performed to expand the liner are summarized in this paper.