What is Cold Root Rolling?

1/27/2019 | 5 min read

The oil and gas industry depends on well-built, reliable pipeline systems to transport materials safely and carry out efficient, smooth operations — from extraction and refinement to eventual delivery to the customer. Proper care and maintenance are critical for keeping this essential infrastructure in good working order, ensuring optimal worker safety and environmental friendliness while protecting the bottom line.

A failed connection in this industry can cost up to $250,000 per day, and on an offshore platform, mitigation is inherently more complicated, time-consuming, and costly. Therefore, any innovation that can increase the durability of the pipeline system and its components is a smart investment, which is where cold root rolling comes into play.

The Cold Root Rolling Process

Cold root rolling is employed to lengthen the lifetime and increase the durability of pipe thread connections, greatly reducing the effects of corrosives and the general wear and tear inevitable in high-pressure and high-saturation environments — such as those found in offshore drilling.

This advanced thread rolling process involves burnishing the root radius of a previously or newly cut thread; essentially, a roller is forced over the root to burnish it. The roller is made of hardened plastic that changes the structure of steel materials on an atomic level; the work-hardening effect changes the structure of the steel, replacing the crystalline structure with a dislocated, interlocked one. This process results in a stronger, more durable material able to resist cracking, tensile stress, corrosion, and other damaging effects that can lead to catastrophic failure.

The process also results in residual compressive stress, offsetting the tensile stress involved. This stress balance reduces the risk of overall pipe failure while allowing for a better chance of successful repairs when needed. Finally, cold root rolling smooths away scratches and imperfections, reducing the chance of chemical corrosion, which can eventually undermine the integrity of the pipe connection.

The Benefits of Cold Root Rolling

Since oil and gas pipelines are in constant use, all of the benefits discussed above can allow for significant cost savings. The tools and processes involved in cold root rolling are simple and intuitive, allowing it to be done virtually anywhere onsite, and under most conditions. Furthermore, cold root rolling tools adhere to API standards, which are relevant to nearly 90% of all pipe connections in the oil and gas industry.

To recap, below are some of the key benefits of cold root rolling:

Significant cost savings
Higher-strength, more durable steel
Better protection from harsh environments
Reduced risk of failure
More reliable, safer operations
Higher chance of successful repairs
Reduced chemical corrosion
Simple, intuitive process

And since extraction is increasingly done is harsh, hostile environments, cold root rolling has become critical for establishing the safest, most resilient setup possible. The extreme environments inherent in offshore sites, for instance, as well as extended-reach and complex lateral/horizontal well applications, necessitate the most reliable materials to ensure optimal profitability.

Cold root rolling can be applied just about anywhere, under any circumstances to reduce the chance of failure and extend the life of the materials in critical pipe connections. Not only do these benefits drastically cut down on the costs of service and repair, they also allow for a safer, more reliable system.

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