A Technical Moment with David Parramore

Jun 4, 2021

TSC Subsea
TSC Subsea

A Technical Moment with David Parramore, Operations Director of TSC Subsea UK

  1. What brought you to TSC Subsea?

    I had already worked with the TSC Subsea founder/management team during my research days at University College London. When TSC Subsea changed focus from writing technical software to producing NDT instrumentation, the chairman approached me about starting the electronics and instrumentation department. I had a keen interest in the electronics of NDT instrumentation, so it was a really good fit for me.
  1. ACFM® is rather well known in the market, what is actually ACFM and how is it different from other technologies?

    ACFM is an electromagnetic NDT technique born out of the ACPD technique. ACPD is a direct contact, voltage measuring technique and great for sizing defects. Unfortunately, it has a couple of drawbacks — when scanning to detect defects, namely contact bounce and the requirement for extreme cleaning.

    ACFM was invented to overcome these limitations, while retaining the advantages gained in using a theoretical approach to modeling current flow in metals. ACFM uses induction to introduce a uniform electrical current in the test piece surface, and sense coils to measure the small AC magnetic field. Thus, removing the need for such good cleaning.

    The measurements can be related to field theory similar to that used in ACPD so crack sizing is possible without needing a calibration test piece. The technique was developed for the energy industry, and probes take advantage of uniform field features. These advantages include an insensitivity to lift-off, so the technique works well through coatings or residual marine growth. The technique can also determine crack depth over a wide range, so that crack penetration depth can be estimated is accurate even if the defect is nearly through wall. This is a clear advantage, particularly in the offshore energy sector and underwater, where lift-off is difficult to control due to residual marine growth and coatings and structural material thickness can be 30mm or more.
  1. What major market trend shifts have you noticed during your career?

    The majority of subsea inspection is performed by divers, but the drive for lower costs and improved safety has seen the market shift toward remote methods.
    For the last 10 years, TSC Subsea has specialised in providing remote-deployed inspection solutions for the offshore industry. The growth in this area is very significant with most major operators now dedicated to performing all offshore subsea operations without divers if at all possible. TSC Subsea have overcome the challenges in performing many remote inspection applications. The NodeScanner ™ tool developed by TSC Subsea is recognised as the world’s leading technology for inspection of tubular welded jacket nodes. Using this tool, the inspection process has become routine with many offshore inspection campaigns completed annually.
  2. How is TSC Subsea technology different from another supplier?

    TSC Subsea is the inventor of the ACFM technique, so it possesses the skill and experience to achieve success with these tools. Direct influence over the instrumentation specification has made the NDT equipment appropriate for the job. TSC Subsea have added many technologies to the inspection toolbox and now offers ACFM and Acoustic Resonance Technology systems together with suitable remote-controlled scanners and robots.

    TSC Subsea has the support of the Eddyfi NDT group and can field a dynamic research and development team to help solve the many challenges involved in subsea inspection tasks. Its development engineers are embedded in offshore teams — which not only helps ensure that jobs run smoothly — but also captures essential feedback that allows the company to make continuous improvements to the technology.
TSC Subsea ACFM MAGCRAWLER
MagCrawler™
  1. How significant a role does subsea robotics play in current and future markets?

    Most offshore asset owners are look for safer, more cost-effective methods for conducting their business. They demand that the inspection process is performed remotely where possible.

    Robotic systems have now come of age and are delivering on these key metrics. Oil and gas are ever-increasingly being extracted from deeper waters as the resource becomes more scare. The transition from diver-deployed to remote robotic deployment is poised to increase dramatically in the coming years. Part of the reason is that the technology has proven itself in successfully completed projects. TSC Subsea has positioned itself to capture a significant portion of this growing market opportunity.
  1. Are there any notable projects that you’d like to highlight?

    There have been many interesting projects during my time at TSC Subsea. A notable Norwegian company were early adopters of the ACFM technology. They operated with the strict goal of keeping divers out of the water. One application involved obtaining access to the leg support of a rig structure through a 300mm diameter aperture. No tooling was available that would suit this challenge.

    The NDT was scheduled on the internal structure, several meters away from the access aperture. The company pulled together a team involving several companies and TSC Subsea. Jointly TSC Subsea developed a technique that allowed it to send the tool through the access hole, navigate to the inspection site and then perform a detailed inspection looking for small surface-breaking fatigue cracks. The system involved the use of micro ROVs equipped with ACFM sensors; so, the whole package could fit through the 300mm hole and operate successfully on the other side.

    DNV were heavily involved in assessing the quality and reliability of the inspection with detailed factory acceptance testing performed successfully before the offshore work began. The first job was completed successfully — a real tribute to the personalities and drive of the personnel involved. One of the requirements was to monitor the structural integrity of the structure going forward, so TSC Subsea returned many times over a six-year period, often with new tooling and an expanded scope of work. The company developed the ACFM MagCrawler™ as part of this work. It’s now become a regular tool for offshore ACFM inspections.

    The structure of the asset has now been modified to eliminate safety concerns. TSC Subsea were a key part of this process and is recognised for saving substantial costs for its client. It has been a really rewarding project and some of the techniques learnt are very much in use today.

    Recently, TSC Subsea has completed a really challenging, tight access node inspection around the riser support structure of a rig in the UK sector of the North Sea. The tooling design took just six weeks and the work was completed successfully offshore.

    This project really demonstrates the fact the TSC Subsea can respond very quickly to solve inspection challenges in the subsea sector. The company’s drive to deliver outstanding service to its customers not only produces great feedback for the company but also for its delivery team, who remain focused and enthusiastic about their work.

    Dave Parramore is the Operations Director at TSC Subsea. He’s been with the company for over 30 years and specializes in ACFM, and other electromagnetic measurement and inspection systems. He’s also experienced in underwater and topside inspections within the oil and gas, nuclear and power generation sectors.

    For more information about TSC Subsea, visit www.tscsubsea.com

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