Abstract
Operating and maintaining a healthy well is a demanding task for every energy producer worldwide. The loss of production and emerging environmental issues due to leaks is a concerning event and needs an immediate solution. Surface and downhole leaks on any well indicate a loss of well integrity barrier. The utilization of high-performance chemical sealant to reinstate the well barrier is evaluated during a non-routine well integrity campaign.
The approach was to gather and analyse the well leaked info data for each leak case. A methodology was then developed to properly design the diagnostic and rectification plan. Various leak-sealing principles were investigated during this stage. Several system integrity tests (SIT) were performed to demonstrate and approve the leak-sealing concept on a laboratory scale. Combinations of Pressure-activated sealant (PAS) and time-activated sealant (TAS), either polymer and epoxy resin-based, provide a wide range of leak-sealing opportunities for surface and downhole leaks.
A total of 10 well barrier elements (WBE) on different wells were diagnosed and rectified using high-pressure sealant, which includes downhole packer, surface wellhead component, sub-surface control line, and conductor casing. Most of the WBE reported experiencing unique leaks during diagnostic, and the correct sealant was deployed according to the design methodology and procedure. Acceptance criteria of well barrier enveloped were followed to qualify the rectification works. Ultimately, all 10 WBE managed to be rectified riglessly during the campaign.
The paper delineates the process of choosing a leak-sealing methodology and sealant working principle for each individual well integrity rectification, while also emphasizing the various factors that must be considered during the engineering study, diagnostic, and rectification activities, and the deployment strategy. Additionally, the paper shares the experiences and lessons learned during the execution phase. Finally, the paper also summarizes the post-monitoring result after one year of leak sealing application.