June 2021, Vol. 248, No. 6
Features
A Different Perspective on Pipeline Repairs
By Molly Laughlin Doran, Pipe Spring LLC
I am a proud, second-generation energy professional. I am Mom to an energetic toddler. I am a volunteer advisor to a (Generation Z) women’s organization on a large college campus. And, I truly love pipelines.
I love that our community literally keeps the world energized and moving. I love that throughout my career, I have been involved in making critical infrastructure safer. If you ask anyone who has worked with me over the years, they will tell you I really am that enthusiastic about our industry.
In my relatively short eight years working in the pipeline industry, I have had three amazing and wise female bosses. These incredible women, mothers and pipeline champions have helped me reach my goals, given me access to spaces that were once male-dominated, and were incredible stewards of my career.
I also have been mentored by some of the kindest and supportive male executives who have shared their talent and insight. They have provided me access to their industry resources with a simple ask.
Both of these groups of people eventually led me to own my own company, Pipe Spring LLC. In many circles, this female-influenced and male-supported career would be considered quite progressive and forward-thinking. If I were not writing this in Pipeline & Gas Journal, it could be mistaken as commentary about a newer, sexier, more woke industry rather than our pipeline industry.
The truth of the matter is pipelines keep our world functioning, and I have been lucky enough to experience the best our industry has to offer. It is with this enthusiasm and deep care for our industry that I am asking the pipeline community to look at pipeline repairs in a new light.
We have a chance to do more than just make repairs; we have an opportunity to truly enhance pipeline integrity or augment pipe. We have an opportunity to do more for stakeholders and the opportunity to change the perspective Generation Z has of our industry with the small decisions we make each day. Choosing a technically sound repair that offers an opportunity to sustainably augment pipe is one of those small decisions.
Background
For the past few decades, the industry has been repairing pipelines in the same fashion. Typically, either welded steel sleeves are used on our pipe, Type A or Type B, or composite materials such as E-glass, carbon fiber and Kevlar are used to repair defects. Both of these methods of repairing pipe have challenges and advantages.
Welded steel sleeves obviously require welding. Clearly, the safety of the repair could be maximized if welding near the fluids carried within pipelines could be eliminated. The preferred method’s design guidance of welding on pipe and pressure vessels, as well as cyclically loaded structures, strives to eliminate all partial penetration welds, use fillet welds only for shear applications, avoid striking arcs on the body of the weldment and use subsequent weld beads to refine grain size.
Welded steel sleeves for pipeline repair applications tend to violate some of these traditional best practices. In addition, the fit up to pipe is not always perfect. The result can be less than optimum performance. However, steel may be a proffered material because it will not degrade over time.
Composite repair options may eliminate the welding issues but introduce another set of challenges. For one thing, composites repairs will degrade over time. Both the strength and effective modulus of elasticity may degrade. Thicker repairs are required to handle the strength issue.
The modulus issue is not often addressed. The architecture of specific composite repairs can result in the requirement to have fibers straighten prior to sharing the stress from the pipe. The initial stress/strain response can display a significant delay. Some systems can require significant skill and care during installation. However, the elimination of welding can be preferential.
Several years ago, the inventor of Pipe Spring studied this feedback from pipeline operators and realized that, in general, pipeline operators preferred steel as a material for use on pipelines, but they often preferred the installation methods of composite repairs due to the elimination of welding. This sparked an idea, and the Pipe Spring system was born.
The System
This steel spring system combines the material properties of steel with the advantages of a composite installation style. Thin-layer steel is utilized, and a modern toughened methyl methacrylate adhesive system is used to create a laminated steel sleeve system. A two-component epoxy system is used as a filler material to fill any area of metal loss, or it is used around any weld or other protuberance on the pipe.
Test Program
The resultant steel sleeve provides reinforcement to the pipe and effectively mitigates various integrity threats. It can be used as a repair system. It also can be utilized to augment existing pipe for purposes of a change in design factor, class location change, pressure increase or to provide additional known properties so that your pipe can become traceable, verifiable and complete (TVC).
Full-scale testing of this system has been completed. ADV Integrity completed the burst testing on this system in 2019; since then, additional internal and external tests have been conducted. Complete and thorough literature on these tests is readily available.
It is true that repairs can be made on pipelines with a variety of technically sound options. What makes the steel spring system different from your average repair system is its nearly immediate stress/strain response time, the ideal material properties of steel and the cyclical performance of the adhesive system. These factors allow the steel spring system to augment pipe rather than simply repair it.
The engineering for the repair of pipe has long focused on the restoration on the theoretical hoop stress or pressure-containing ability of a repaired pipe section. This has been effective. However, a more holistic approach would include axial strength and other engineering parameters. With this system, we add material with the material property benefits of steel to the pipe.
Again, important characteristics of this system include isotropic properties and a modulus of elasticity matched to that of the pipe and the elimination of degradation of material properties during service.
The thin-layer-laminated design promotes conformity and fit up to the pipe, which benefits the immediate shared stress/strain response. The adhesive selected is toughened for maximum cyclical performance as well as resistance to shock and vibration loading. The advantages and implications for mitigation of strain-based concerns enable “Augmentation of Mechanical Properties of High-Pressure Pipe,” the title of U.S. Patent 10,830,383.
We can add strength not just in the hoop-stress direction but also in the axial direction. We can add toughness to the existing pipe and increase intrinsic mitigation of potential future outside force trauma. At this point, we can begin to make the pipe better than it was. The concept of augmentation of pipe does involve a change in our traditional thought pattern. It is time to think beyond repair.
A Hypothetical
A pipeline operator lacks information on the material properties of an older piece of pipe in his system. This section of pipe is not considered TVC; however, the pipeline operator does have a recent known safe operating pressure.
With this information, assuming it is Grade B pipe, we can add material to the pipe with known material properties. The hoop-strength calculation is straightforward and follows the industry’s standard Barlow equation method. The key to strain, concerning the axial strength component and toughness, is addressed by augmentation of the existing mechanical properties.
The newly augmented pipe segment behaves and operates as a single unit. The matched modulus of elasticity of the steel strength member with the pipe, and the elimination of delay-in-response, enables this extension of our traditional methods. Pipe that was once unknown can now have known material properties and can be documented in an appropriate way.
Sustainability
Another important component of this steel spring system is that it can be a tool to help pipeline operators meet the companies’ emissions reduction goals. For about two decades, the industry has recognized that the prudent use of repair methods could help eliminate the venting of greenhouse gases (GHGs).
With the prudent augmentation of pipe comes the ability to further minimize venting of GHGs. We also can minimize the need to cut out and replace sections of pipe. This obviously would eliminate GHG venting or emissions and eliminate the risks of unscheduled releases. It also would eliminate the carbon footprint of replacement pipe.
As an industry, we have not placed a significant focus on the carbon footprint of new pipe. A quick internet search indicates that other industries are focusing on emissions from steel production. One statistic found by such a search reveals that 1.8 tons of carbon per ton of steel is produced. A replacement joint of pipe may well be a few tons of steel with additional carbon emitted for transport and installation.
The future of our sustainability efforts may well include a thorough review of our practices and required changes to our traditional mindset.
System in Use
The Pipe Spring system is now in use on regulated pipelines in North America. Additionally, it has been added to multiple companies’ operating and maintenance language as an acceptable repair option. Our next step is to focus on the benefits of pipe augmentation rather than just repairs.
The skills of the field personnel and the variables of field installation are often a key component of effective repairs or mitigation of various concerns. The vast majority of reported problems or troubles with these mitigation efforts or composite repairs are traced back to poor installation.
The repair systems typically are designed well, but the installation in not always done well. Field training and various regulatory efforts have been focused on this issue. During the development of this laminated steel sleeve system, we concentrated specifically on the potential to simplify and reduce field variables, as compared to other existing technology options.
We made design selections to help minimize reliance on highly skilled personnel and to minimize installation variables. We also have used recent technology advancements in adhesive system performance and dispensing methods.
As mentioned, I spend a great deal of time with Generation Z, volunteering as an advisor to a collegiate women’s group. Over the past few years, I have watched young women I consider to be future leaders, business moguls and entrepreneurs passionately oppose pipeline projects.
I have watched them “check in” on social media platforms from Texas to protests in other parts of the country, hoping to confuse law enforcement. I have watched them post article after article online from enemies of the pipeline industry. This isn’t a majority of the women I volunteer with, but it is important to realize this is happening, even in the state of Texas that holds oil and gas so near and dear.
More Perspective
These women want the best for their future, and I do as well. I think the future has room for pipeline infrastructure and for technology that challenges us to move beyond just repairing pipelines toward augmenting them. As pipeline projects become more difficult to permit, augmentation and better repairs may be necessary tools to solve a tough problem.
As pipeline a pipeline professional, I have solicited feedback from thought leaders in the industry. Sometimes, I hear feedback that doesn’t have anything to do with technical substance, but instead points out that changing procedure and paperwork is difficult, bureaucracy is hard to move, culture takes time to change and dollars already have been spent on validating much older technology.
What do we think the Generation Z women I advise, and the general public for that matter, would say about these excuses? I know these women well, and I believe they would expect the stewards of the pipeline industry to make decisions based on technical ability and performance, rather than the fact it is a pain to edit operating and maintenance language.
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