Quotation from Neil Addison, Subsea Operations Manager
“Halfwave have delivered an exceptional quality pipeline inspection within a challenging schedule target. I have been impressed with the level of customer focus, problem solving attitude and both the quality and speed of final deliverable submission. The technology we used enhances inspection quality, reduces offshore execution time and therefore reduces overall risk. I look forward to working with the Halfwave team again.”
It is Halfwave's focus to deliver high quality and efficient inspection services to all our clients. Therefore, we are very pleased to hear the positive feedback from AkerBP with regards to the recently completed inspection of Valhall 20" Oil Export Pipeline Inspection. For more information of the project, please see case study provided by AkerBP to Halfwave AS as below. Halfwave look forward to continue supporting AkerBP in the future.
Successful first use of pipeline inspection technology
In November 2017, a number of external wall loss defects were identified on the Valhall 20” Oil Export Pipeline. The defects were revealed by an ultrasonic in line inspection between Valhall PH and Ekofisk, which is part of a risk based integrity management programme.
All of the defects were found within a 50” bundle, which runs subsea for around 150 meters on the East side of the Valhall facility. The bundle contains four separate pipelines – 20” Oil Export, 10” Flank North production, 10” Flank south production and 12” Hod production, which his currently out of service and preserved.
The damage could soon consume pipeline corrosion allowance and if left unmitigated could result in loss of containment or reduced lifetime. Repair or replacement would be extremely expensive. The finding was placed high on the asset risk management register to communicate the issue and prioritise multi-disciplinary attention.
Neil Addison, Subsea Operations Manager, adds: “We held a series of engineering reviews to understand the risk, determine what the inspection revealed and what the potential causes could be. Although we could shortlist a few more likely failure modes like uniform corrosion, microbial induced corrosion or mechanical wear, we couldn’t be sure what was happening. We therefore couldn’t recommend a way to stop the problem.”
Anita Rimereit, Riser and Pipelines Engineer, continues, “With Aker BP’s focus on new technology we receive a number of technology based presentations. One of these was from Halfwave where they showed us some new acoustic inspection tools. One of these would be able to see through the oil export pipeline wall, and reveal if there was any mechanical contact with the pipeline, potentially causing surface damage.”
Typically, in line inspection of the oil export pipeline has needed thorough wax removal before accurate results can be achieved. This requires four separate cleaning pig runs, driving an offshore campaign of about 20 days.
After deciding to progress with the Halfwave ART Scan, the team worked through the Easter period to plan, risk assess and execute the inspection – a technology first for Aker BP. The tool was sent from PH on 5th April as part of a 6 day offshore campaign, and received at Ekofisk 36 hours later.
After downloading data at Ekofisk and processing information at Halfwave’s Oslo headquarters, results from the inspection were with Aker BP within 2 months of the technology presentation.
The inspection confirmed damage seen previously. It also revealed that although there was expected mechanical contact between the oil export pipeline and structural supports every 4 meters, the damage sites were not related to this contact. One failure mode has been eliminated and an upcoming vessel intervention campaign will focus on the remaining possibilities.
Christian Tangen, Asset Operations Manager concludes: “This is a great example of Engineering, Asset and Halfwave working effectively together to deliver fast and accurate results. Although we have a lot of work in front of us to diagnose and mitigate the risk, this inspection puts us in a better position to do so. In addition, the inspection took 6 offshore days compared with 20 for a traditional inspection. This should reduce inspection costs and execution risk on all Aker BP assets going forward.”
Figure 1: An image from the 20” pipeline. The light blue section is 0.1mm thinner than the dark blue sections. The yellow and red patches are external damage.
Figure 2: Offshore team in action loading the ILI tool at PH (photo: Christian Rott)