NEW RELEASE TOOL FOR PREMIUM PACKERS ENABLES P&A IN NORTH SEA

Welltec® Releasing premium packer

Background

An operator in the North Sea needed to plug and abandon the main wellbore in order to drill a sidetrack. To prepare the well, the operator needed Welltec to shift and release a premium packer. However, the design of the premium packer created some unique challenges for latching. The shifting profile incorporated angles of 45°, much lower than other designs. The lower the angle of the mating elements, the higher the required pad pressure from the Well Key® in order to grip and move without slipping out of the profile. Further, the Well Key normally performs an ‘active search’ for the shifting profile while being pulled back on the wireline winch. But this very high pad pressure required to remain latched once the pads are located is actually sufficient to lock the tool in place, preventing the tool for locating and latching as normal. Therefore, operations on premium packers require extremely precise depth control and the use of a NO-GO solution.

Searching for a better approach, Welltec used both its own observational data as well as experience gained from a previous intervention with this same packer model to design a new solution. The result is a new hydraulic shifting tool, the Well Key® 318 Lock Grip. The release tool was designed to search for the shifting profile using a new 360°, six-arm profile. This enables the efficient active search mode approach. When the tool engages the correct inner diameter, it mechanically locks in place and instantly latches to the profile. Once latched, it has sufficient contact to allow the Well Stroker® to pull maximum force immediately upon its first stroke.

OPERATION

Prior to this operation, two SITs confirmed that the new release tool could latch and stroke in the premium packer profile and that the tool could provide enough force to shift the premium packer. Welltec brought the newly released tools to the North Sea in June 2016 to perform the shift to release intervention.

Well Key 318 Lock Grip was run into the well with the rest of the toolstring. Once at depth, the toolstring was accurately correlated and put into active search mode. The release tool locked onto the premium packer profile, creating an immediate overpull on the winch. The Well Stroker was activated to anchor and then pull up, shearing the packer. Technicians on surface knew the packer had been released when a 1.85-cm shift occurred. The Well Key and Well Stroker were deactivated and the toolstring recovered back to surface. During the second and final run, the Well Cutter® cut the tubing at 1,830 m measured depth.

ACHIEVEMENTS

Consistently innovating on our unique portfolio of intervention technologies, Welltec® created a solution to improve efficiency and accuracy for operators using premium packers with the newly designed release tool. Welltec successfully shifted the premium packer used in this well with 100% operational efficiency enabling the operator to carry-on with the P&A and subsequent sidetrack operations.