Safaniya Jacket Removal, KSA

Utilising its innovative ultra-high pressure (UHP) abrasive water jet internal cutting system, James Fisher Offshore (JFO) has successfully completed a slipover jacket removal as part of a wider decommissioning programme on one of the world’s largest offshore oilfields.

Project scope specified use of an internal cutting system with capability to cut the piles to a minimum of 1.5mtr below seabed level. Each pile was estimated at 19mm WT and 23mtr in length. JFO created immediate cost and time savings for the client by mobilising from its base in KSA, deploying its UHP abrasive water jet internal cutting system capable of delivering speed, reliability
and accuracy.

JFO’s knowledge and experience were ably demonstrated during first deployment with an unforeseen protrusion within the pile at 9mtr. Mitigating risk, avoiding delay and associated cost, the JFO team
drifted to guarantee clearance of the downhole cutting head (DCH), performing the first cut at 1.5mtr above the seabed.

Excavation was then launched on the soil plug inside the pile utilising JFO’s bespoke Airlift tool to provide clearance for the DCH to perform the clients requirement of severance 1.5mtr below the seabed.

The unique airflow of the JFO cutting system negates the need to de-water, minimising the equipment requirement and delivering an impressive 60% reduction in overall cutting time.In parallel, the cut verification system ensures complete operator and customer certainty,
reducing the risk of stitching and, ultimately, reducing risk of over-run on high cost projects.

All jacket legs were successfully cut ahead of schedule, using the cut monitoring and advanced control system to perform the cuts without damaging the adjacent live risers.

The combination of the JFO teams’ experience, the advanced control system and cut monitoring, enabled the onsite adjustment of cutting speed to ensure successful cut. On this occasion, this resulted in variation from the client’s original stipulation of 19mm pile WT to the recorded 70mm pile WT upon completion of jacket removal.

Each pile took in the range of 6-8 minutes to excavate with the bespoke airlift tool. The cut timings for 70mm WT piles was a very efficient 16 minutes.

“The JFO team have been nothing but
helpful and professional throughout this job.
Nothing was too much trouble and their knowledge
and expertise of the cutting system was invaluable”

Client ROV supervisor

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