The petroleum industry relies heavily on drill strings— i.e., a series of pipes and piping components that are threaded together. These assemblies are highly complex, involving many critical parts, each of which must be adequately maintained to ensure proper function. However, as drill strings are often used in extremely harsh environments, performing the required maintenance can be challenging, prompting rising demand for connections with greater durability and longer service lives.
Cold root rolling serves as a preventative measure to failed connections. The process involves burnishing connections within the structure, which can extend the lifespan of drilling equipment by up to three to five times. Failed connections threaten efficiency, sustainability, and profit (up to six-figure losses due to downtime each day). In a single week, offshore operations can lose millions of dollars based on the integrity of a single string connection. With such high stakes, cold root rolling is a sound investment that promises to safeguard equipment and maximize its working life.
What Is Cold Root Rolling?
CJWinter, a Rochester-based company, is the industry leader of this innovative technology. The cold root rolling process changes the molecular structure of steel to enhance its durability under harsh working conditions. To accomplish this, qualified technicians burnish the root radius of threads in rotary-shouldered connections throughout the piping, altering the steel’s crystalline structure to yield dislocated, interlocked steel. The result is a work-hardened surface that is far less susceptible to damage, structural flaws, or shallow cracking.
Impact on the Oil & Gas Industry
Cold root rolling process was engineered with the needs of the gas and oil industry in mind. It yields clear benefits, such as:
- Improved drill string strength. Drill string components must withstand significant stress under increasing performance demands, whether they’re part of an offshore, extended-reach drilling, multi-later well, or horizontal well application. Cold rolled (remove Burnished) steel is stronger and better able to withstand the routine demands of all of these applications.
- Increased resistance to thread root stress. Cold root rolling produces residual compressive stress, which offsets tensile stress in integral regions of the root thread. Balancing these forces reduces failure rates and increases the chance that a damaged component can be repaired successfully.
- Reduced corrosion. One of the main risk factors for corrosion is scratches or imperfections in the steel’s surface. The process of cold root rolling smooths away surface damage, reducing the chance of chemicals accessing and corroding the metal.
- More in-house work. The cold root rolling process is simple and accessible for all oil and gas operations. New technicians find it easy to learn the intuitive tools, minimizing the time and labor investment required to take advantage of the technology.
The collective sum of these benefits is increased joint durability and, consequently, reduced downtime due to the lower risk of failures. These benefits also translate to:
- Cost reductions in many areas, including equipment replacement, maintenance, repair, and spill cleanup
- Increases in employee safety due to the decreased potential for malfunction
- Decreases in the company’s environmental footprint due to fewer spills from equipment failure
Experience the Benefits of Cold Root Rolling With CJWinter
Although cold root rolling generally finds use in offshore drilling applications, the greater durability of equipment components afforded by the process also benefits onshore drilling applications. With the growing ubiquity of extended-reach drilling, multi-lateral wells, and horizontal wells, the amount of stress—and the consequent damage—placed on onshore threaded connections has increased. Cold root rolling can mitigate this trend.
Cold root rolling is suitable for all thread types, not just standard API (American Petroleum Institute) thread forms. The co-inventor of the cold root rolling process has reported success with many proprietary thread forms, resulting in considerable and quantifiable improvement in the fatigue life of connections with non-standard configurations.
At CJWinter, our groundbreaking cold root rolling technology has improved the lifespan of thousands of drill string connections across diverse applications. Your operation could be next. To learn more about cold root rolling technology, contact us today. If you’re ready to invest in more durable drill strings and less downtime, request a quote.