As the infrastructure of a subsea pipeline system ages operators may run into serious structural problems, making integrity management a significant priority over the lifetime of the system. Sensor technology and advanced analytical metrics are critical to the development of an efficient integrity management system, an expert said.
In a presentation held at the 2016 SPE Delta Section Deepwater Technical Symposium in New Orleans, Partha Sharma discussed the application of sensors and analytics in pipeline integrity management systems. Sharma is a research and development program manager and leads the risers and flowlines section at DNV GL.
He said a strong management program begins at the highest levels of management, with executives who are willing to issue a mandate emphasizing pipeline integrity. A proper organizational structure should support that mandate, as clear lines of communication and clearly defined contingency plans, operational, and management procedures help avoid confusion in implementing the program.
Most importantly, Sharma said pipeline integrity management programs should be focused on the management of information from various sources like inspection reports, monitoring results, or an owner’s design specifications.
“As these assets age, and we have a transfer of assets between companies, information tends to be lost. That creates problems down the line if you are going to manage the integrity of a pipeline,” Sharma said.
In addition to the different streams of information, a strong management program must incorporate the various concerns that operators, regulators, engineers, and integrity managers may have when inspecting a pipeline. Sharma said these concerns may not be in complete alignment.
For instance, regulators need to ensure compliance with government standards, so their primary objective is to understand and oversee any high-risk elements of a management system. Operators often seek to minimize costs while achieving an acceptable level of system integrity. The integrity managers are often fitting their work scope within the constraints of the owner’s budgetary and schedule demands. Engineers must assess integrity based on information that may not be readily available, incomplete, or insufficient
“You may have to make quite a lot of assumptions in your assessment, and those assumptions can have significant bearing on the conclusions that you write,” Sharma said. “Therefore, it is essential for the engineers to have all the information handy.”
Sharma said sensor- and analytics-based integrity management systems provide continuous monitoring, which helps develop trends over an extended period of time. These trends allow operators to understand previously unknown loading conditions that may affect long-term pipeline health, and additional information can help them prioritize inspection locations and frequency.
A probabilistic risk model based on a Bayesian network can take into account various failure mechanisms, such as internal and external corrosion and vibration, to give an overall picture of the pipeline system, informing operators of potential high-risk areas. Physical inspections—in-line inspections, cathodic protection surveys, mechanical damage inspections, and coating breakdowns—are still necessary, but sensor-based systems help reduce the number of inspections needed, thereby lowering operational costs.
“We want to optimize the physical inspections based on our digital equipment, which is a numerical model with different elements backed up by sensors,” Sharma said.
Among the sensors Sharma discussed were fiber-optics sensor and acoustic emission sensors. Fiber-optic sensors can measure pressure, temperature, and leaks and acoustic emission sensors can be used for leak detection, erosion, and corrosion monitoring.