Non-destructive leak testing can improve pipeline sustainability
A leaking pipeline can cause an inordinate amount of legal, safety and environmental risks, which is why oil and gas companies delegate a large percentage of their time and resources toward detecting and preventing leaks. While operators look to put more miles of pipelines into production, some face regulatory hurdles in certain regions, which forces companies to rely on aging infrastructure that is many decades old.
In both instances, advanced non-destructive leak testing has become a primary component of overall operational pipeline performance, and companies are doing more to prevent spills in a more efficient manner.
According to The Associated Press, the number of accidents on oil and petroleum pipelines has increased 60 percent since 2009. This is largely due to the vast expansion of pipeline throughput, but also because leak testing measures were not as widely implemented as they could have been. For instance, operators that utilize traditional methods of leak detection may face longer downtime, effectively ceding efficiency at critical moments. Since service technicians often must turn off pipeline valves and cut into the walls of the production asset to identify or correct a given problem, operators essentially stood at a standstill while their infrastructure was tested.
“Leaks can be located using non-invasive methods, which puts pipelines back into production more quickly.”
However, with non-destructive testing, leaks can be located using non-invasive methods, which puts pipelines back into production much more quickly.
Benefits of NDT
Leaks can go undetected for undue periods of time if the right measures are not taken. During this timeframe, not only do operators suffer the loss of valuable resources, but the surrounding environment also faces risks from spills and waste chemicals.
To reduce the chance of this occurring, non-destructive testing techniques, such as burst, valve and certification testing, may be employed. Additionally, engineers can use tracers, currents or transients to specifically locate the portion of the asset that is weakened.
These procedures do not require the destruction of pipeline components to gain an accurate calculation, which protects operators’ assets. Similarly, on-stream leak methods can be customized to assess the condition of a pipeline during its pre- and post-commissioning.
Whether it’s during the initial construction process, prior to final commissioning or when the pipeline is in full production, NDT serves a vital role to the total mechanical capacity of the asset.
The immediate and long-term benefit of this type of methodology is that pipelines are deemed more sustainable and will suffer from fewer incidents of mechanical failure.
Common leak testing procedures
Many pipeline operators make use of pressure, ultrasonic and radiography testing, all common NDT techniques.
The Pipeline & Hazardous Materials Safety Administration stipulates routine integrity assessments of pipelines through pressure testing. In this instance, service technicians would insert a high-pressure gas into the pipeline’s normal flow. The goal is to increase the amount of pressure that is beyond what the pipeline operates under during standard operation. By holding this elevated pressure level for several hours, operators can gauge how well pipelines hold up under adverse or potentially risky conditions.
“Operators can gauge how well pipelines hold up under adverse or potentially risky conditions.”
Additionally, through the use of high-frequency sound, engineers can assess the thickness, strength and condition of pipeline components. This non-invasive ultrasonic test has superior Probability of Detection (PoD) results and enables operators to obtain a more specific inspection of their assets, thus facilitating a greater chance for full regulatory compliance.
Radiography testing is a real-time scan that produces images of the walls of the pipeline, exposing flaws and the presence of corrosion. The information of this scan is stored digitally and can be compiled with data from other assessments to form a complete calculation of the pipeline.
These NDT procedures not only provide operators with the information they need to prevent leaks, but also to protect their assets from coming under duress in the future. An AP examination of federal data indicated two-thirds of pipeline failures occur due to corrosion and equipment failures. However, these issues are preventable. During a standard leak testing, other malformations may also be uncovered, giving operators a clear sign of the type of structural improvements they need to make to ensure asset integrity.
As more companies onboard the latest NDT technologies, the nation’s entire pipeline network will become safer and more resistant to harsh or corrosive elements.