When drilling an offshore well, an operator experienced a hardware failure that led to the accidental cementing of more than 500 meters of drill string. To try and recover the well, it was decided to remove the cemented drill string section by section, which required that it be cut in such a manner that would allow it to be pulled out one stand at a time.

Time was of the essence, and to assure that cutting could be performed safely and correctly – even in places with pipe in compression – the operator developed a plan with Welltec® to utilize Well Cutter® technology.

Within 24 hours of the urgent request, both Well Tractor® and Well Cutter solutions were mobilized to the rig. As the drill string was both in compression and stuck in cement, it was not possible to pull the drill string in tension, and thus the operator wished to proceed with the Well Cutter based on its track record and ability to cut in compression.

The 5” drill pipe with 3.5” minimum ID upset internally meant that the operation was performed with the Well Cutter 3 1/8 with machine arms.

On the first run, two cuts were made and the tool was pulled out of the hole to inspect the pad wear. Virtually no pad wear could be seen. At the surface, Welltec engineers could document that two successful cuts had been made, and it was decided to continue the operation but with more cuts to be made per run.

Accordingly, on the second run alone, the Well Cutter managed to perform seven cuts, confirming the crew’s anticipation and resulting in a new world record for the Well Cutter.

Over the course of all runs, a total of 24 successful cuts were made.

The mechanical cutting was performed in just two days and the entire operation was conducted in one week.

No other mechanical cutter would have been able to perform under such high compression, while explosive cutters would have meant one cut per run, as well as additional dressing, and runs on drill pipe for fishing i.e. 24 wireline runs and 24 extra dressing runs.

After the operation, the client was impressed with the tool’s abilities to cut in compression and perform multiple cuts in one run.