Well Cutter® 238 cuts 3-1/2" tubing in seven minutes

March 2017, North Sea. To facilitate the frac stimulation for an offshore well the 3 ½” completion needed to be cut and then removed, and a 4 ½” frac string installed in its place. Initially, explosive cutters and even coiled tubing cutters were considered. However, being aware of the high level of success with non-explosive cutting, the client contacted Welltec®.

Welltec has a strong track record using the larger Well Cutter 358, and had recently debuted the smaller Well Cutter 238. The client chose the new Well Cutter 238 for the job based on recent successes and the time and accuracy advantages offered by e-line over coil. The client also preferred the smooth, beveled cut that the mechanical cutter creates, which would make it easier to stab back onto the 4 ½” tubing.

A test cut was performed onshore with a sample of the tubing to be cut – 3 ½” 9.2# Cr13 L80. The cut was completed in six minutes. The client then simulated the next stage of the operation, using the overshot to be run-in-hole, on the stump left by the WCC cut. It was an easy fit, demonstrating that no dressing of the stump would be needed. The tools were then mobilized offshore to perform the operation.

The Well Cutter was run-in-hole with a Well Tractor® 218, in case conveyance was required to reach the depth required. The Well Cutter made a perfect cut in seven minutes. Additionally, during subsequent operations, the Well Cutter was used twice, to cut the tail pipe when the bridge plug could not be pulled by coil. In all, three cuts in the 3 ½” tubing were made throughout the operation. The cutter performed flawlessly each time, much to the customer’s satisfaction.

Welltec successfully met the client’s objective by cutting the 3 ½” tubing to re-complete into the 4 ½” frac string. The primary cut took seven minutes. Additionally, the Well Cutter exceeded client expectations by performing two additional cuts in the tail pipe to drop away stuck plugs.

Welltec’s e-line cutter reduced risk due to the non-explosive nature of the tool and the smaller equipment footprint on the rig when compared to heavier methods such as coil. In addition, the Well Cutter saved the client one to two days by rigging up on e-line instead of the full coil spread.

The client is now considering other new techniques, including those offered by Welltec, for completing and working over wells, owing to the potential time and money savings as well as the reduction in risk offered by light interventions.