Abstract Objectives/Scope Well integrity monitoring is one of the critical processes in oil and gas wells to prevent unintended fluid movement or loss of containment to the environment. In this case study, there was continuous gas leakage to surface at high pressure through annulus "B" of an oil well in East Kuwait area. The detection and securing of the gas leak in this well was essential not only for securing the well and restoring production, but also for environmental considerations due to the sensitive geographical location. This paper presents an innovative logging combination for total well integrity assessment, including spectral noise, high-resolution temperature, multi-barrier corrosion evaluation, and fluid type identification for downhole gas leak detection. The paper also presents remedial actions taken to secure well integrity after assessing and evaluating diagnostic logs at each stage with a workover rig.
Methods, Procedures, Process Innovative combination of different measurements for total well integrity assessment including spectral noise, high-resolution temperature, multi-barrier corrosion evaluation, and fluid type identification logs have been used to detect the downhole source(s) of this gas leak. Multiple cement squeezing across single and multiple casings were designed and performed based on the logging results to stop the leak and secure the well. After completing each cement squeezing job, surface pressure in annulus "B" was being monitored and downhole logging surveys were being performed to check if there was still downhole gas flow.
Results, Observations, Conclusions The different logging results showed strong indications for multiple sources of this gas flow in annulus "B" across different formations around the well. The poor primary cementing job allowed formation fluids (e.g. gas, oil and water) to migrate to shallow reservoirs and surface. The remedial cement squeezing jobs have been successfully performed and achieved a solid hydraulic vertical barrier to stop the gas flow activity. The gas flow stopped, surface pressure in annulus "B" disappeared and restored production of 700 bopd from the well.
It is a case story of a successful well integrity workover in a very challenging well that ended by fixing the gas leak, restoring the well production, protecting the surrounding wells and environment, and saving the cost of either sidetracking the well or P&A (plug and abandonment).
Novel/Additive Information The innovative well integrity logs in combination with conventional cementing remedial jobs, allowed us to achieve complete well integrity. The use of advanced well integrity logs (e.g. spectral noise, high-resolution temperature, multi-barrier corrosion evaluation, and fluid type identification) were beneficial to determine the exact depths of the leak points and determine the exact location of the remedial jobs (e.g. remedial cement jobs) to stop the migration of gas from the formation to shallow reservoirs and surface.