Well type
Test well - Ullrig, Norway
Deviation
27°
Depth of operations
545 and 557 mRKB
Plug and abandonment (P&A) operations present numerous challenges, from managing time and cost efficiency to ensuring regulatory compliance and long-term environmental protection. Wells completed with control lines on the outside of the production tubing introduce additional complexity, as these lines must be properly addressed to prevent creating potential leak paths (micro-annuli) that could compromise the integrity of cement barriers.
Axter is a future-ready electro-mechanical solution designed to significantly expedite such P&A operations by optimizing the control line retrieval process into three stages in a single run: scan, mill, cut and retrieve. This technique eliminates the need to remove the production tubing, leaves the completion ready for cementing as the primary well plug, and for all intents and purposes facilitates rigless plug and abandonment operations.
To validate this transformative solution with the endorsement of a globally leading operator, Welltec and Axter conducted a full-scale system integration test at Ullrig in Norway — a premier piloting center for drilling and well technology, systems, and methods.
A full-scale integration test of the Axter system was conducted in Well U-08 at the Ullrigg test facility, targeting the retrieval of control line(s) from a 4-1/2" (12.6 ppf, L80) tubing set inside 9-5/8" casing. All actions were performed at two target locations 545 and 557 mRKB, with a deviation of approximately 27° at that interval.
While the full Axter solution typically begins with real-time acoustic scanning to locate control lines within the annulus, this step was omitted in the test environment due to the pre-characterized well configuration.
Stage 1 - Axter Lateral Miller – Axter Line Cutter
The Axter toolstring was run in hole to a depth of 557 mRKB. At this depth, a 200 mm (7.9") lateral window was milled into the tubing to access the external control line, which was then cut using the integrated Axter Line Cutter.
The toolstring was then repositioned to 545 mRKB for the upper cut. A second window was milled, and the control line was again accessed, cut, but this time retained in the Axter Line Cutter and retrieved to surface – completing this part of the sequence.
Stage 2 – Cast/Sleeve installation – NTS (additional run?)
Following retrieval, two Axter Cast sleeves were installed to seal the milled windows and restore tubing integrity — a critical step for preparing the completion for permanent abandonment.
These operations validated the ability of the Axter solution to execute both precision retrieval and post-intervention sealing under representative downhole conditions.
The Ullrigg test successfully validated the Axter method as a viable, efficient, and field-ready solution for the plug and abandonment of wells with control lines on the outside of the production tubing.
By executing a complete cut-and-retrieve sequence followed by precision sealing of milled windows, Axter demonstrated its capability to simplify one of the most complex P&A challenges — without the need to pull production tubing.
This outcome affirms Axter’s readiness for field deployment, particularly in wells/fields where control lines have historically imposed high cost, complexity, and rig dependency during abandonment.
