Well type
Oil, cased hole
Max. temperature
Above 150-175°C / 300-350°F
Pressure
Below 12 kpsi / 830 bar
Offshore North Sea, a client needed to perform a temporary plug and abandonment on a subsea well. The client contracted Welltec to cut the 7” tubing using the Well Cutter®. The operation would be carried out via a lightweight intervention vessel several months prior to rigging up and ultimately pulling the tubing.
The client needed enough flow through the cut to ensure that the well could be killed. The operator anticipated the tubing cut to be performed in compression, potentially making flow through the cut more difficult. An explosive puncher was arranged as a contingency solution. The client planned for Welltec to make the tubing cut with the Well Cutter which can cut pipe in compression and then pull out of hole to determine if the flow through the cut was sufficient. This process would result in an extra run in case the flow had to be increased.
To avoid the potential use of an explosive cutter, Welltec proposed to combine the Well Cutter with the Welltec Puncher® in the same run. A non-explosive tool, the Welltec Puncher equalizes the pressures between tubular strings and can create several holes in the tubing at selected depths.
The tool string included a customized standoff to ensure that the orientation of the Welltec Puncher was at either 90° or 270° from the horizontal well axis. Additionally, a Well Hardware Scanner was also used in combination with the Well Cutter and Welltec Puncher to confirm the puncher’s orientation.
During the run, the Well Cutter cut the 7” tubing, and the Welltec Puncher drilled six holes with a 12 mm drill. Drilling took only 30 seconds per hole and achieved enough flow to meet the client’s objectives. The customized standoff oriented the puncher to the lateral side of the tubing, and the Well Hardware Scanner (WHS) confirmed that the orientation was at 270°.
This successful operation was the first time the Welltec Puncher was used. It worked in combination with the Well Cutter to cut the 7” tubing and ensure that the flow through the cut was sufficient to kill the well, all in one run. Sufficient flow was achieved after the puncher drilled six holes. Moreover, the WHS ensured correct orientation, thereby protecting the casing and also confirmed there was no casing damage. The combined use of these tools resulted in an accurate and safe operation.
By choosing the combined Well Cutter and Welltec Puncher for this operation, the client did not need to mobilize explosive cutters or punchers. This reduced the amount of required deck space on the vessel. It also reduced the risk to both personnel and equipment by avoiding explosives handling. Finally, the client saved critical time by successfully completing two tasks during the same run. This consolidation saved the client over 12 hours in operational time while also reducing total cost.
