EmPulse logging for workover planning
Corrosion has a dramatic impact on well completion integrity, HSE, productivity and economics.
The Corrosion Assessment Service of TGT’s Well Integrity Platform is designed for through-tubing thickness scanning of up to three pipe barriers using the EmPulse logging tool.
The well surveyed by TGT was drilled and completed in 2003 as a three-leg horizontal ESP oil producer. In September 2016, the Client planned to perform a workover for ESP replacement. Before the workover, the Client created a task force involving TGT to assess the tubing and casing condition, its reusability for installing a new ESP, and the condition of multiple strings in order to have a coherent workover plan.
A decision was made to carry out a rigless multi-string corrosion evaluation. TGT’s EmPulse* tool was employed to assess the condition of the 4-1/2″ tubing, 9-5/8″ production casing and 13-3/8″ casing for the subsequent development of the workover plan.
Logging was performed successfully, and the EmPulse* tool data showed that the 4-1/2″ tubing was parted (Zone 1 in the figure) and that significant tubing corrosion occurred above the ESP (Zone 2).
In addition to these findings, TGT’s electromagnetic tool detected up to 20% metal loss in some intervals of the 9-5/8″ production casing. The evaluation that was simultaneously performed on the 13-3/8″ casing did not show any significant metal loss.
A workover was scheduled and logistics arranged to replace the tubing only in intervals affected by corrosion rather than the full string. Additionally, a scab liner was mobilized to the location as a contingency plan in case the pressure test to be conducted for the 9-5/8″ casing, fails.
After the completion was pulled out of the hole during the workover, the presence of significant corrosion zones in the 4-½” tubing above the ESP was confirmed. Also, the ESP string was found parted in the depth interval indicated by the EmPulse* survey. Because of corrosion found in the 9-5/8” casing, the client proactively ran a 7” scab liner based on TGT’s findings to extend the life of the well despite positive pressure test results.
TGT’s well integrity team employed the EmPulse* state-of-the-art technology before a workover to assist the Client in
• Proper planning of operations, resources and contingencies
• Well life extension through proactive actions
• Minimization of operational time and costs
The resulting collaborative environment and the right use of the technology reduced operational unknowns, increased operational effectiveness, minimised costs and extended the well life.