Interview with Ben van Bilderbeek - Focus Reports

Featured in Focus Reports Special Supplement

Published June 2014

Plexus is primarily known for its POS-GRIP® technology, but when this technology first emerged, what advantages did it have over conventional 'slip and seal' techniques and the subsequent unitized 'mandrel hanger' systems? 

The technology is a new method of engineering for wellheads, which Plexus invented more than a decade ago. The original patents have a few years left to run, although importantly the company has many continuations and new patents that have emerged over the years which extend the unique rights Plexus holds with regard to the technology. In particular developments in relation to bringing the technology subsea has resulted in strong new IP that will extend protection for the technology a further 20 years.

POS-GRIP wellheads are capable of delivering the considerable and measured force required to engage sealing and load bearing parts together without having to remove the well control equipment (blow out preventer) located on top. Wellheads are an essential part of a long equipment chain that is required before a well can be put into production. As the proprietor of this unique technology Plexus is keenly focused on the most safety critical part of this chain for all applications, but particularly offshore where the cost of operations are the highest and the risk of failure is the most severe!

The most critical aspect of wellhead technology is the ability to deliver the force necessary to hold components together, as pressures and temperatures vary considerably and on a cyclical basis. Movement as a result destroys the integrity of seals over time, as is the case with conventional wellhead designs. The destructive conditions in production wells are significant at any pressure but particularly dangerous in high pressure high temperature (HPHT) applications where gas pressures of up to 20,000 psi are involved.

The capacity to deal with temperature and pressure induced forces that occur over a very long period of time need to be an integral part of a wellhead design, and the systemic deficiencies of conventional technologies render these systems unsuitable for high pressure and temperature applications.

We hear about Plexus doing from the outside-in what the industry has for a century done from the inside-out?

Traditional slip and seal and unitized mandrel hanger technologies rely on being able to do everything from the ‘inside-out’, whereas the friction-grip method of engineering on which POS-GRIP is based simply squeezes the outer body of the wellhead against an inner casing hanger body from ‘the outside-in’, thereby gripping adjoining parts together as if they are ‘cold welded’ together for eternity. The procedure is conducted within the elastic range of material, and therefor remains releasable, whilst being immovable to any force encountered in the well bore.

HPHT technology is however not the only part of wellhead design that requires reconsideration, as gas at any pressure can be dangerous. For Plexus wellheads follow the ‘golden rule’ that assembly is such that Blow Out Preventers (BOPs) remain on the well throughout the drilling programme.
Additionally annular seals are designed so that integrity is maintained throughout the life cycle of a well rather than just during assembly testing, without the need for maintenance, as is the case with conventional systems.

Why is the lifting of BOPs so dangerous?

When casing is installed in the ground cement is displaced to seal this metal barrier into the formation. During the process cement slurry is pumped into the annulus between the ground and the casing, providing a perfect hydrostatic seal as it displaces drilling fluid in the hole. Once the cement hardens, which takes valuable time, the seal mechanism in the annulus changes from a hydrostatic effect to a mechanical bond between the casing and the ground.

As the only barrier in the system, the mechanical seal in the wellhead serves as a second barrier as is the convention in the industry.
Safe well control practice dictates that before a barrier in the well is removed the replacing barrier should first be put in place and that is precisely what does not happen when BOPs are lifted to terminate casing in a conventional wellhead system.

As a result a freshly cemented well is left open to the environment when the BOPs are removed with just the cement in the annulus as a single barrier to keep the well under control.

Today most systems still require that BOPs are lifted before casing can be suspended in the wellhead and its continued use is often justified by the need to deliver clamping force to the hanger to wellhead interface which can be readily achieved with these systems, but requires moving BOPs.

With the introduction of its patented friction-grip technology, Plexus has devised a solution where installation of casing can be conducted with the BOPs remaining on the well, whilst also delivering a measured and controlled gripping force to the casing or tubing hanger interface, thereby providing the best of both worlds.

The technology is based on a system where load rings are hydraulically squeezed together on the outside of the wellhead housing and using a tapered ring to constrict the outer body until it grips the inner hanger on which casing is suspended and where multiple metal- to-metal Hertzian Contact Stress seals are energised, all in a single action.

You write about the importance of delivering force to the wellhead. What is the issue?

In order to be safe for HPHT applications wellheads must provide metal-to-metal sealing across the casing annuli.

The only system we know of that can achieve this in the wellhead environment are seals designed and installed in accordance with Hertzian Contact Stress principles.

POS-GRIP® technology is a convenient and simple method of automatically delivering precise force within Hertzian Contact Stress design limits, so that seal integrity is guaranteed under high pressure and temperature cycling, with casing forces retained throughout the life of a well.

One essential element of Plexus’ effort to improve operations around the world is their focus on elevating qualification test standards for wellheads so that they match those for the other connectors in a well, such as the casing and tubing couplings. For too long the industry has lived by the mantra that the least common denominator should do and certainly in HPHT applications only the best available and safest technology (BAST) should become the benchmark standard.

We spoke of the need to make wellheads the “Strong Link” in the well chain, and what is all this talk about instant casing lock-down?

Current qualification standards as promoted by API and ISO are in Plexus’ opinion inadequate for HPHT applications and we have therefore set the goal to only supply wellheads qualified as the “strong link” for any well under any condition.

Particularly in subsea applications there are no differences between the function of a casing hanger as compared to a casing coupling. Both must hold pressure from two directions and suspend the weight of a long casing string, where incidentally the casing hanger is located at the most upper point. Therefore the massive gap between the qualification standards required for casing hangers and casing couplings makes no sense and Plexus has done something about that, by testing our casing hangers as if they were casing couplings – therefore no weak links in the well chain!

On the issue of casing hanger lock-down much work needs to be done by our industry. In a recent paper we analysed the various lock-down methods currently in use around the world in subsea and surface wellheads. Without exception all systems currently available lack the lock-down capacity required for safe use under HPHT conditions and most worryingly, current suppliers all claim to provide metal sealing capability without ensuring that casing hangers are fully locked in place under all operating conditions.

In the USA instant casing hanger lock-down, as soon as cement is displayed, is in in the new drilling rules as a result of the Deepwater Horizon incident, but in the UK, which claims to operate under the best regulated system, this decision is still up to the operators, as if it can ever be safe to ship fizzy cola without crimping the caps to the bottle necks.

We learned that ITF in the UK put out a call to the industry for casing annulus pressure management solutions. Is Plexus working on this?

The ability to set multiple annular seals in series inside a subsea wellhead bore is one of the special features that can be provided with POS-GRIP technology. When ITF came out with their recent call for solutions to deal with sustained casing pressure (SCP) situations in subsea wells, we immediately responded with clearly articulated solutions. Sadly the industry response has to date been negative with the major objection cited that such information and response capability in subsea wells will lead to complex and expensive modifications in subsea production systems down the line.

Undeterred Plexus will continue the R&D on this subject and will as part of our “HGSS” subsea wellhead JIP demonstrate how uniquely easy it is to provide annulus monitoring, bleed-off capability and remedial access using POS-GRIP technology.

Beyond the technical capacities of your technology, what commercial incentives do companies have to adopt your new subsea technologies?

We called our seal technology “HG”. This stands for ‘Hot Gas’ service. Privately we muse that “HG” represent a Holy Grail solution for wellhead seals, as the friction-grip method of engineering enables Hertzian Contacts Stress principles to be applied in remote subsea applications, where competing technologies have a difficult time delivering force to the hanger to wellhead interface.

To Plexus Hertzian Contact Stress Seals are the only technical and effective solution for metal sealing in wellhead applications and we are able to deliver this critical technology for HPHT applications with a system that requires fewer components and which is assembled in such a simple way, that installation time savings render the technology cost negative.

Had the industry embraced POS-GRIP technology earlier and assisted Plexus with its development then our efforts could by now have been directed to many other applications, including tanker mooring systems and tie-back connector’s.

Our mission for years has been to persuade the industry to recognise and accept the safety and operational benefits of POS-GRIP technology, in the hope that eventually other manufacturers would adopt the friction-grip method and develop their own versions of the technology under license for the greater benefit of the industry.

Patents: your R&D budget increased by 22 percent last year - what projects are under development and what is the next POS-GRIP technology?

We were initially able to attract customers by making sure they were exposed to POS-GRIP systems on temporary surface applications, such as exploration wells drilled from jack-up-rigs. This was the easiest option for us, as we can rent equipment to clients for the short term, whereas production wellheads can be in the field for 20 years or longer.

Following the Deepwater Horizon incident some of our customers were looking to apply our proven surface technology subsea. The Macondo well had raised questions about the conventional methods of locking down casing hangers and many experts have speculated that better devices for keeping casing hangers from moving in the wellhead bore would be of benefit for the safety of future operations. In the event Plexus’ was invited to take its technology subsea - resulting in the “HGSS” JIP coming into being.

Although the project is firmly focussed on instant and reversible lock-down of casing and tubing hangers in the remote environment of subsea wells, a number of additional targets were identified, and these have become areas of application into which we are expanding. Of particular interest is the reduction of the installation trips required to assemble a subsea wellhead system. As a small company with a disruptive technology we are in no doubt that in addition to improving technology we also have to provide economic benefits before operators will switch to new way of doing things.

The elimination of wearbushings, annular seals, lock-ring, and lock-down sleeves in subsea wellheads will all add up to the obviation of numerous subsea installation trips resulting in savings of many million dollars per well depending on water depth!

Senergy recently joined the JIP - what benefit do they and the other parties bring to the venture?

Senergy do a great deal of well design, planning and equipment specification around the world, and have been a partner with Plexus for some time on jack-up-applications for mutual customers. As a client, they benefit from technologies which save time - reducing the number of trips that wellhead equipment must make, and therefore the cost of their operation, which goes straight to the bottom line. Senergy knows that Plexus delivers better technology and savings on the surface and have experienced good results with our technology over a number of years. Now they want to help make the same happen subsea, which is the reason why they are entering into this unique partnership. Because of their late entry it was agreed that Senergy will provide useful cost comparison analysis against conventional subsea designs based on their extensive and varied worldwide experience in planning the drilling of wells of huge variety.

Plexus has previously had a North-Sea focus - how important is this market to you still, and how important is international expansion to your strategy?

The Scottish and Norwegian North Sea territories continue to be important for us although as has been widely reported a slowing down of investment has resulted in a reduction in exploration investment and activity. However sales in this region still account for circa 30% of our revenue. Following the recent report by Sir Ian Wood on the future of the North Sea, combined with a range of tax incentives for HPHT drilling, and bearing in mind increasing political uncertainty around the world, the Plexus Board is confident that recent trends will reverse and that the North Sea sector can once again become the vibrant and growing industry it used to be.

Our company recently opened business in Singapore and we are in the process of expanding this operation by keeping an inventory of exploration wellhead equipment ready for short term deployment, whilst building a team of sales and administrative personnel. We also are currently operating in Africa, Middle East and Far East, and recent contracts in China and Australia continue to extend our reach.

Where does Plexus find the balance between wanting this technology to be the new industry standard, and developing the technologies within the company?

Plexus definitely wants the technology to be adopted as a new and superior standard, and does not see itself as the sole purveyor of the technology. It would be far beyond our company’s capabilities and ambitions to develop all the potential applications of the friction-grip method of engineering. We clearly think that wellheads can be designed much better and safer using POS-GRIP technology and as our industry moves deeper and at higher pressure and temperatures, better and safer technology is essential. We are concerned that asset impairment issues can obscure opportunity for advancement and we see it as our task, as the inventors, to prove the technical viability, commercial impact and safety benefits of the technology, application by application. We genuinely believe friction-grip engineering to be BAST (best available and safest technology) for wellheads and since the technology has managed to unite superior performance with cost reduction and safety benefits, its application makes sense across the application spectrum.

To expand this business, we will have to demonstrate the capabilities of our technology to a standard beyond what is customary. Additionally we are discussing with our “HGSS” partners how to solicit customer support in pulling the technology into the market place.

At some stage regulators will play their part as there are areas of subsea technology that have not yet been developed, but which will feature in future project. Subsea casing annulus pressure management, which to date was considered not technically feasible, will within the next decades become common practice and friction-grip technology provides a practical solution which will be part of the final deliverables of the joint venture.

What are the barriers to spreading this technology?

The main barrier is the usual ‘not invented here’ syndrome, combined with disruption of the natural order which affects suppliers and their customers. Asset impairment issues are caused when new and superior methods of engineering are introduced in critical applications. In response Plexus is prepared to make POS-GRIP technology available on equitable terms, such as a RAND (reasonable and non-discriminatory) licence, so that in theory all wellhead companies and operators can have access to it on equal terms. Such an approach has been proven to work well in other industries, as it tailors royalty expectation to volume of sales.

If friction-grip technology had been invented by for example, GE, that company would have by now strangled the market with its potential. As a small company, we neither have the capacity or the will to do this, and we look forward to the day the industry at large joins us in the application of this far better and safer method of engineering for wellheads.

Plexus was born as an innovative company, but what is the business doing to keep this value – innovation - at the heart of the enterprise?

We have an active corporate engineering and research and development (R&D) program going, trying to capture the IP for other applications. Plexus knows the recipe, and is aware that the secret of a technology is out when you patent it. For this reason, there is a great deal of engineering skill and know-how that we like to keep ‘close to our chests’- particularly with regard to static friction and how to deploy it effectively. Historically, this form of connection had been used to connect aeroplane propellers to the aircraft, for example, but the load was far lower - Plexus conversely is working above 20,000 psi with proof loads at 30,000 psi across an 18 inch pipe for example. This generates pressure end loads of 7,000,000 lbf or over 3,500 tons. This is, to use the aeroplane analogy, the weight of 10 jumbo jets.

In our interview with Professor Von Prondzynski of RGU he mentioned that Scotland still needs to move further towards pursuing innovation as a means of enhancing its industrial capabilities. As an engineer who has invested time and effort to create a successful business here in Aberdeen, what would you say the relative health of entrepreneurial spirit was here in Scotland?

Every day, Plexus’ activities are centred on innovation, so the spirit of innovation is certainly alive here. In the wider oil and gas industry, there is often a tendency to swallow up innovation in larger organisations, and sometimes as a result it gets ‘strangled’. There is a great deal of innovation that is unseen, and goes on in large oilfield services companies, so progress is harder to evaluate in the round. Companies like Plexus however, are the evidence that innovation goes on all the time, and we fully intend to continue to demonstrate this ability.