North Sea well access restored through intelligent wireline intervention

Wellbore cleanup used an advanced magnet that withstands high temperatures without losing strength. Real-time feedback from instrumented active debris removal tool helped clear more than 400 L of formation debris, opening 335 m of obstructed wellbore.

Dropped coupon and debris obstructs wellbore

An operator offshore UK was faced with a major challenge when the lower coupon of a surface lubricator valve was not captured as planned by a third-party milling company and fell downhole into the well. The operator also suspected debris accumulation downhole. When the tubing becomes packed off with particles produced from the formation, it not only has a detrimental effect on production rates but can be a symptom of a larger issue. Removing this debris becomes imperative to a healthy well operation; leaving it too long will require a much more intrusive workover to restore production. To remedy the situation, the operator asked SLB Fishing Services to help retrieve the dropped valve coupon and remove any other debris from the well.

High-powered magnet provided a rapid solution

One important tool brought to the job was the High-Temperature, High-Strength Magnet, part of a large that can reduce operator downtime when unexpected events occur. Unlike conventional magnets, the magnetic insert is customizable with different sizes that can withstand prolonged exposure to very high downhole temperatures without losing effective strength. The uniquely powerful magnet has succeeded in removing unwanted ferrous objects in many difficult fishing scenarios, such as those encountered here. Rapid response from the planning and execution teams enabled the coupon retrieval to be conducted with minimal delay. The crew lowered the magnet into the hole and retrieved the coupon on the first try, thus preventing loss of the wellbore and enabling the intervention to continue as planned.

Active debris removal tool enabled real-time feedback on collection efforts

The second part of the solution involved the ReSOLVE™ instrumented wireline intervention service, which includes an active debris removal tool that maximizes the success and versatility of any cleanup operation. The active debris removal tool does not require additional pumping of fluid because localized well fluid circulation generated downhole collects debris into a bailer for capture.

Deploying the tool on instrumented wireline provides pinpoint depth control combined with surface readout of the tool status and positive indication when the bailers are full. Fine-tuning the active debris removal tool enables recovering a large range of particle sizes simultaneously, while real-time feedback ensures maximum debris collection for each run.

The data output to surface lets the operator know when the active debris removal tool is near capacity or is having plugging issues. A special control module enables the built-in progressive cavity pump  (PCP) to reverse direction and jet the plugged debris from the collection nozzle to loosen particles for easier collection. 

Following this method, the active debris removal tool was used on 24 consecutive runs retrieving more than 400 L of formation debris and opening 335 m [1,110 ft] of obstructed wellbore. It also provided samples for investigation into failure mechanisms. The success of the retrieval operations proved that both the fully instrumented ReSOLVE services and tool portfolio deliver excellent performance in extreme recovery situation.