Rigless recovery of 30 multi-string conductors using a time-saving solution

PROJECT OVERVIEW

Aker BP was seeking a strategic partner to perform a conductor removal on their Valhall drilling platform (DP) decommissioning project.

The Valhall field is in the southern part of the Norwegian sector in the North Sea, and although the field has been in production for several decades, Aker BP sees enormous potential in the area. The work of modernising Valhall is well underway and involves removing old platforms, plugging old wells, investing in new wells, and supporting facilities.

THE CHALLENGE

Due to the tight schedule of the project, Acteon’s Cutting and Decommissioning business segment needed to find an innovative way to reduce the multi-string conductor recovery time.

CUSTOMER GOAL

To remove 30 multi-string conductors (30” conductor/ 20” casing and 24” conductor /18 5/8” casing and 1 x 26” conductor) on time and safely, within budget and without using a jack-up rig or platform-based drilling derrick, whilst reducing the drill, pin and cut time during conductor recovery operations from 2.5 hours per sequence.

OUR SOLUTION AND ITS COMMERCIAL BENEFITS

Market-leading services and integrated solutions

• We used our in-house design engineering capabilities to develop DPC-E; a new electrically operated system that can automatically drill, pin and sever casing and conductors in a single operation, whilst maintaining a data link onshore via WiFi/ethernet connection for problem solving and reporting purposes.
• The full-service package was provided including rigless recovery system, bespoke equipment, ancillary tooling and localised multi-skilled crew to perform operations.
• We integrated products and services including WellRaizer®, DPC-E, marine growth removal tool and lay down bucket to form a decommissioning package all operated by the same multi-skilled crew.
• We utilised market-leading technology that resulted in considerably improved operational timings and therefore increased value creation over existing equipment.
• All equipment supplied for the campaign was certified to NORSOK Z-15, which ensures adequate safety, value-adding and cost-effectiveness for the operation.

Operational bases across the world

• Equipment was shipped from our Great Yarmouth base to Norway, providing proximity to the client.
• The WellRaizer build and testing took place in-region at our Claxton AS Forus facility.

Work at scale with a proven track record for delivery

• We have an extensive global track record of conductor cutting and recovery; 200+ wells cut in Europe, 1000+ wells cut in the USA and 80+ wells cut in the Far East and applied this recovery experience to the Valhall project to optimise recovery operations, integrated the best tooling package for the job and ensured that the customer’s goal to markedly reduce the 2.5 hours cut time per sequence was met.

Optimise the project to increase the commercial value

• Conducting a rigless operation can save money on expensive rig mobilisation and day-rate hire.
• The conductor recovery time was significantly reduced using the DPC-E, meaning less time was spent completing the operation.
• The compact profile of the WellRaizer system means it has a smaller footprint; a time-saving benefit when it comes to mobilisation and set-up.
• By supporting the ongoing modernisation/decommissioning of the area, we contributed to Aker BP’s goal to reduce overall decommissioning cost for the existing Valhall installation.

Minimise the environmental impact

• Multi-skilled crews, local bases and supply chain, reduced personnel mobilisations and kept project carbon emissions to a minimum.
• Eliminating the use of a jack-up rig or platform-based drilling derrick and replacing it with the smaller WellRaizer modular lightweight recovery system reduced mobilisation and operational carbon emissions.
• DPC-E was specifically designed with reducing CO2 emissions as a primary objective – as the system can be powered by the platform/rig supply, there is no need for diesel generators or similar.
• The development of Claxton’s bespoke equipment contributed to faster, safer, and more sustainable plugging and removal of wells.

PRODUCTS USED

• WellRaizer modular lightweight recovery system for rigless multi-string conductor recovery.
• DPC-E; a newly developed electrically operated system that drills, pins, and severs casing/conductor in a single operation.
• DPC-H; a hydraulic combined drill, pin sever machine as a backup to the DPC-E. (Designed, built and delivered but not used. DPC-E was used for the whole project.)
• Landing/pulling string for the 24”, 26” and 30” conductors.
• Laydown system for cut conductors, eliminating the need for manual handling.
• Prime Mover to move the DPC-E in and out of the well centre by remote operation on WellRaizer.
• MGRT for high pressure jetting/blasting of marine growth for safe setting of slips during recovery operations.

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