Submitted by Proserv
Proserv’s Multi-String Cutting (MSC) tooling was efficiently integrated with the drill pipe and recovery operations were optimised to allow the recovered wellheads to be removed from Proserv’s tool string without disconnecting the control lines or the tooling from the drill pipe. This minimised the time between deployments to the time required to skid between the wells.
Through the deployment of Proserv’s MSC tool the operator was able to achieve a smooth frictionless cut through multiple casing strings, cemented or not, in one trip. The rigidity and control of the drill pipe coupled with the sealing mechanism on the Proserv MSC decreased cutting times by around 25 per cent. This ultimately contributed to the successful, safe abandonment of the eight wells, well ahead of schedule.
The use of abrasives cutting technology, as part of a plugging and abandonment campaign from a semi-sub drilling rig, is believed to be an industry first in the North Sea.
Description of Best Practice
Proserv was contracted by a North Sea operator to abandon eight Category 1 subsea wells from a semi-sub drilling rig using our Multi-String Cutting (MSC) tooling, which uses abrasive water cutting technology. This tooling has an established track record in the Gulf of Mexico from vessels and platforms, and was introduced into the North Sea in 2014. Proserv has a successful track record in the North Sea of abandoning more than 20 Category 1 wells for multiple operators from light well intervention vessels. For this work scope, Proserv’s MSC tooling was deployed from a semi-sub rig using drill pipe. The MSC assembly was integrated with a wellhead retrieval tool that latches into the profile of the camhub wellheads. This allowed the cut and recovery of the wellhead to be carried out in a single trip regardless of casing configuration.
Over the course of nine operational days including recovery of the wells to deck and skidding the rig, Proserv successfully abandoned all eight wells. The well architectures had a variety of casing designs ranging from 10.75 inch through to 30 inch conductors.