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.

Added Value:

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.
March, 2017