Pipeline operators and contractors are focusing much of their attention on potentially game-changing technologies in the areas of continuous monitoring and inspection.
To some extent, they may focusing too much on detection solutions, contends David Edgar, vice-president of the pipeline business unit of Mustang Engineering LP, Houston.
“I believe that everyone is concentrating too much on detection and not prevention,” he said. “Of the possibilities listed, the only one that prevents failures is cathodic protection.”
On the other hand, cathodic protection isn’t a magic bullet for ensuring pipeline integrity, according to Essam Zaghloul, president and CEO of FOX-TEK Inc., Toronto.
“Cathodic protection is a trusted method of preventing corrosion, but there are always those exceptional areas where the CP system is not working perfectly,” he pointed out. “In addition, because the CP system does not measure the changes in the pipe, there is no direct way to see if it is working effectively.”
Edgar maintains that if the threat assessment has determined that the largest threat is external, the pipeline is not able to pass a smart tool and cannot be taken out of service: “I would look at a direct assessment program coupled with good cathodic protection.”
In-line inspection technologies
Today, the most significant contribution to pipeline integrity is being made by new technologies that operators can use to improve their continuous monitoring capabilities, Zaghloul contends.
[In-line inspection] is also a trusted tool, but the high cost of running these tools prohibits their use to once every 5-7 years,” he said. “A lot of changes in product and operating conditions can happen to a pipe in that time that may result in increased corrosion rates. To a lesser degree, the improvements in ILI technology between runs sometimes makes the comparison of data difficult. Leak detection is important, but it is a ‘reactive’ approach. A proactive method that finds or tracks problems before a leak occurs would be much more valuable.”
Edgar allows that ILI is a good tool with the potential to be a great tool.
“However, ILI is still not where it needs to be to identify some of the greatest concerns like SCC [stress corrosion cracking], seam defects, and cracks,” he said. “ILI can reliably detect gross defects but still does not have the capability of reliably detecting and locating smaller defects, such as corrosion pits.
“If the largest threat is internal and the system can be removed from service, I would tend to look at ILI technology. The ability for the equipment to locate smaller anomalies with very accurate X-Y coordinate data is good. ILI also has the ability to discriminate between internal and external anomalies. It is able to detect actual wall loss.”
However, there are some concerns with ILI, Edgar noted: “Some ILI tools are unable to see or resolve information inside of cased pipe. Anomaly orientation is still a problem. A decision must be made to look for anomalies oriented in the longitudinal direction or in the circumferential direction.
“Finally, the data need to be read and interpreted by a seasoned ILI technician. There are not enough highly skilled technicians to go around for the amount of work. The industry is going through a learning/growth mode at this time.”
Continuous monitoring systems
Advances in SCADA systems and software are making the most vital contribution to pipeline integrity assurance, contends Allen Leatt, chief technology office for Acergy SA (formerly Stolt Offshore), Sunbury-on-Thames, England.
“The ability to monitor, manage, and record real-time information offers enhanced pipeline integrity for pipeline owners,” he said. “Such systems enable integrity management decisions to be made on the understanding of the actual condition of the pipeline.”
He noted that several companies have recognized the benefit of real-time simulation for various uses, such as operator training and process controls (e.g., the expectation of slugs in a first-stage separator).
“Acergy has a team of flow assurance specialists that are fully capable of providing models as input of the integrated SCADA/real-time simulation system.”
While SCADA systems and flow modeling software help make the pipeline operations safer and help operators determine where problems might occur over a vast pipeline network, they’re not measuring the actual changes in the pipe, Zaghloul pointed out.
“New materials that greatly increase the corrosion resistance or the strength of the pipelines are necessary to ensure the integrity of planned pipelines, but the millions of miles of existing pipes are still at risk,” he said. “New technologies, such as FOX-TEK’s FT Sensor System, that can be installed on known problem areas on existing pipelines to continuously monitor changes in wall thickness, strain, or any deformation, promise to significantly increase the reliability of pipelines by allowing operators to know the state of the pipe at any time without having to reexcavate, visit the site, or suffer a loss of throughput.”
However, Leatt noted that while “the integration of fiber optic instrumentation along the pipeline will enable the real-time monitoring of the strain and temperature profile of a pipeline…only a limited number of pipelines can be cost-effectively equipped with such devices.”
Game-changers
New technologies that allow operators to determine ways to mitigate problems such as corrosion, SCC, and leaks will be groundbreaking, Zaghloul reckons.
“Today, most technologies react to problems by providing a snapshot of the condition of a pipeline. Continuous monitoring systems for corrosion [e.g., non-intrusive methods such as FOX-TEK’s FT Sensor System], pitting [e.g., field signature methods], and SCC [e.g., acoustic emission] would allow operators to gather and correlate pipeline condition data with operational conditions [pressure, temperature, product, inhibitor] and then develop strategies to stop the growth of the degradation and prevent it from occurring in other locations.”
In the onshore pipeline construction business, new strain-based pipeline designs are having an impact in the onshore pipelaying world, said Zaghloul.
“Pipeline design/construction companies now include some form of monitoring in the new pipeline specification; however, the future in this area will be dominated by systems that allow continuous, distributed detection of leaks or deformation,” he said.
“In new pipelines, corrosion and leaks from corrosion are almost a non-issue, but deformations from ground movement [frost heave, seismic] can put pipelines at risk,” Zaghloul added. “Being able to detect the precise location and severity of the deformation over distances of tens to hundreds of miles is the goal of these new technologies-many of them based on fiber optics.
Edgar expects to see more emphasis on improvements in detection devices utilizing magnetic fields, electrical current flow, or induced harmonics.
“However, the most significant advancements will more likely occur in improved efficiencies and effectiveness within respective pipeline integrity programs, resulting in model programs emerging and being adopted,” he said.
There is no single tool or technology that will ensure pipeline integrity, Edgar contends. “The area that we are currently concerned with is cased pipelines,” he said. “There is currently only one approved or acceptable tool to test or look at buried, cased crossings, and it is more of a screening tool. We are currently looking at the possibility of other complimentary tools or technologies to help review cased crossings.”
Another game-changing technology of tomorrow for Edgar is a system to identify the presence of excavators on a pipeline right-of-way in time to contact them before they start excavating.
“Such technology could include monitoring the right-of-way with satellites, the installation of sensing devices along the right-of-way, remote-controlled unmanned planes, or installing GPS locating devices in excavation and agriculture equipment.
Sub-One Technology, a small company based in Pleasanton, CA, thinks its new product represents just the kind of out-of-the-box thinking the industry needs-what it describes as a “revolutionary” means to coat the inside surfaces of pipes and parts used in oil production and transmission.
“The process lays down a thin, hard, anticorrosive coating that improves flow dynamics and reduces fouling,” explained Sub-One Pres. and CEO Andrew Tudhope. “The film bonds with the pipe at a molecular level, making it unlikely to detach, like some existing epoxy or plastic coatings. In the unlikely event of a failure, the film returns to a near microscopic size of harmless carbon particles that flow out with the oil.
“Sub-One’s technology still requires some development in order to coat the size parts required for oil transmission, but it should only be a matter of months.”
