Keeping pipelines online with affordably priced wear management
Tom Santos, Weartech™ International (a Lincoln Electric Company), discusses advances in coating technologies that provide affordably priced wear management.
Thousands of miles of oil and gas pipelines crisscross the globe today, providing an immense backbone of a network that ultimately connects the entire system, from the drill pipes in the oil fields to the end users. But like the proverbial strength of any chain, maintaining pipeline integrity relies on continually bolstering up potential 'weak links.' Fortunately, the industry’s growth spurt, which has been ongoing since the mid-20th century, has benefited from a myriad of scientific advances, including huge strides forward in coating technologies.
Today, highly specialised materials and processes afford protection to many of the critical pipeline components at the highest risk of premature deterioration. While numerous approaches have been developed that effectively combat corrosion induced by environmental and other factors, erosion of pipeline components poses an increasing risk. This increase comes as a result of downhole drilling in newer, more challenging environments where penetration through unconsolidated sandstone is challenging but necessary to tap into the oil-rich reservoirs.
Traditional solutions for dealing with high-abrasion conditions, such as tungsten carbide, have been used for years in critical applications. However, such solutions can be prohibitively expensive for widespread deployment on most oil and gas pipelines. That’s the niche market today being filled by newer materials and methods, ones developed specifically to offer appropriately increased levels of erosion protection at a price that makes economic sense.
Newer, less costly abrasion-resistant techniques and materials can be used to clad and protect the actual pipeline, valves, drill bits, pistons, pumps and many other critical components. The materials and application processes offer the capability for internal and external cladding, as well as cladding for high-precision components in need of protection in unique areas with specific surface finishing requirements.
One example of OD protection is hardfacing on drill pipes, referred to in the industry as hardbanding. In this application, hardbanding is applied to the tool joint section of drill pipe to protect the vulnerable joint as well as the ID of the casing it abrades with during downhole drilling.
One of the most challenging unconsolidated oil reservoirs in the world is in Venezuela. A local drilling contractor approached us to provide a longer lasting hardband to exceed the current 1-month tool joint wear life they were achieving. We provided a hardbanding solution that extended that historical performance by 300 - 400%. Use of the same hardbanding solution in other environments has shown a performance increase of 600%, and in some cases up to 800%.
Part of that success, though, hinged on using exactly the right alloy for the hardbanding. Protection of the joint from the rock and sand pumped through the casing is critical to mitigate extreme joint wear and breakage, which could result in pipe replacement and loss of oil. Proper hardbanding on the tool joint also reduces the risk of excessive wear or a blowout to the casing. Because the drill pipe bounces around inside the casing as the drilling progresses, using the wrong kind of alloy will destroy the casing even as it protects the drill pipe.
We chose an alloy with a specific and highly controlled chemistry that results in an extremely refined hardbanding material with a coefficient of friction low enough that it does not damage the casing. Our hardbanding is also compatible with other industry hardbands, making it ideal and easy to use over other materials in both field and shop applications. The result of such careful selection and material matching resulted in a win-win solution for the casing and the drill pipe.
Another interesting example of OD protection involves a large oil company that contacted us asking if we could coat the outside of its pipe, essentially with hardfacing-type material. The problem they were facing was oil theft, which turns out to be fairly widespread. In many places where oil pipelines are above ground, people drill into the pipeline and steal the oil. We were able to provide OD cladding with an alloy that provides an excellent solution, because once it has been applied, the only way to get through it is by using a torch.
Pumping abrasive materials is typically what necessitates ID cladding. Unlike the OD cladding, which is applied in specific locations as needed, ID cladding is generally applied to the full internal section of a component.
The ability to accurately predict wear life is a significant benefit for the companies drilling in the oil sands of Canada, for example. Typically they managed pipeline erosion by periodically rotating the pipe, but that is no small undertaking with the 24 in. to 48 in. pipes in use there. It can take a whole day for workers to remove one side of the bolted flange, after which they rotate the pipe from 12 o’clock to 3 o’clock one time, then from 3 to 6 the next, and so on. Like much preventative maintenance, this type of rotation has been done on an elapsed time basis, and after the standard sequence of rotations, the pipe was replaced regardless of its condition.
Our approach was to coat the entire inside of the pipe with materials we provide, which we refer to as nanoalloys. With a grain structure finer than a microstructure, which refers to micrometers that are 10-6 of a meter, the grain size in these alloys approaches 10-9. With pipe that has its ID coated with nanoalloys, wear life is uniform, predictable and longer-lasting than many industry alternatives, thanks to its refined grain structure. Because this is an engineered solution, those responsible for preventive maintenance on the pipeline now know exactly when to rotate the pipe.
Abrasion beyond the pipe
Another part of our business consists of manufacturing wear-resistant components for pumps and valves using primarily nickel- and cobalt-based alloys. With performance characteristics that go beyond the iron-based nanoalloys used for hardfacing and hardbanding, nickel- and cobalt-based alloys maintain their wear resistance at very high temperatures.
In some cases, we make entire assemblies of wear-resistant material. But, because of the flexibility and expertise we have developed in applying coatings, we also can provide cladding for pump housings and other auxiliary pipeline equipment that offers nearly the same performance at a much lower cost.
On a recent project, we were approached to see if we could extend the life of a fracking pump. The proppant being blended to pump down the well consists of sand, water and chemicals that make the pump’s internal section a highly abrasive environment. The sacrificial pumps were lasting only one week in the field prior to change out. That meant maintaining maximum parts inventory and labor on hand for change outs and maintenance cycles.
Our engineered solution provided an ID-clad pump housing delivering a performance value greater than 700% lifetime increase. Cladding all the exposed metal inside the housing not only extended its usable life, but also took the guesswork out of the maintenance schedule. That, in turn, permitted a reduction in inventory and a lot less headaches all around.
Form and function
How is this ID or OD cladding applied? This question has a number of answers, but the key point is that it is the chemistry, rather than the method of application, that is at the heart of any successful application. Equipment and techniques have been developed that apply these alloys in the form of rods, electrodes, wires and powder. Their application requires a high degree of equipment control supported by engineering expertise.
Highly sophisticated power supplies, such as those available from our affiliated company, the Lincoln Electric Company, are excellent at providing the control and feedback capabilities necessary for these operations. Beyond that, the broad technical support available from Lincoln Electric is also a significant asset. Whereas the Weartech part of the family specialises in providing solutions for extreme conditions, other entities within the Lincoln Electric companies offer proven solutions that work well in concert with those extreme solutions.
We’ve also fine-tuned the chemistries in our alloys to make life easier for the end user, specifically to ensure easy weldability in almost any environment. Our alloys can easily be welded onto other base materials, including our other alloys. To make things easier, no shielding gas has to be used when welding our alloys. That greatly simplifies field applications, such as in oil fields in the middle of the Venezuelan jungle or an African desert where it’s tough to carry gas cylinders.
We have facilities in Anaheim, California and in Wales where we produce the components and assemblies, starting with highly controlled master melt in our own foundries. Coating and hardfacing services, both ID and OD, can be applied at many of our application facilities throughout the world or in the field. Numerous service providers and applicators use our materials, and often do so as a value-add to give them an advantage against the competition. The long and short of it is that ours is truly a customer-driven world.
Considering the variety of solutions and services that we offer, it’s gratifying to say that we hit the entire value stream when it comes to oil and gas applications. From digging the hole, to transporting the raw and finished materials, to the high temperature challenges in refineries, we offer solutions to keep the process going forward and manage the points of extreme demand.
Adapted by Louise Mulhall