March 2017, Vol. 244, No. 3
Features
End-to-End Monitoring, Data Collection Increases Pipeline Safety
With more than 2.5 million miles of pipeline in the United States, proper maintenance and monitoring systems can be key factors in the success or failure of an oil and gas company.
When constructing pipelines, companies put considerable thought and effort into ensuring that health, safety, security, and environmental factors and concerns are fully addressed. However, as lines age and start to degrade over time, maintenance issues rise and monitoring lines and pumps becomes essential to avoiding malfunctions that put employees and the environment at risk.
Due to the differences between subsea and terrestrial pipelines, not to mention the differences between buried and aboveground pipelines, there is no “one size fits all” system for monitoring, but in both onshore and offshore sectors, companies monitor the internal and external workings of the line.
Terrestrial Pipelines
For aboveground pipelines, there are many options in monitoring and maintaining data. Drones, pipeline inspection gauges (pigs), and temperature and pressure sensors are a few of the methods used to ensure that a line is functioning correctly.
Drones are used to periodically survey the exterior of an aboveground pipeline and can cover great distances. Unfortunately, due to the distance a drone may cover and the amount of bandwidth required to send data back and forth, information gathered by a drone can only be retrieved once the drone has returned to offload its data, putting a lag in the time for reaction should a problem be found.
A more aggressive tactic for maintenance is the use of a pig. Like drones, pigs are used periodically to monitor pipelines. However, where drones monitor the exterior of a pipeline, pigs provide insight into the interior workings of a line and can be used in aboveground and buried pipelines.
Pigs are launched down a pipeline, taking ultrasounds of each section as it passes through. This gives a more realistic idea of what type of maintenance plans are needed as it provides companies with the ability to see where the line may have corroded over time or is experiencing a buildup from the hydrocarbons passing through it.
Like drones, communication cannot be maintained with the pig as it moves through the pipeline due to the distance it travels and the amount of data it collects. Also considered a self-contained system, pigs are passed through the line and then recovered, at which time the data is offloaded and sent through the corporate network where it is reviewed and analyzed. With the data collected, companies can create a 3-D map of the entire pipeline infrastructure.
This map helps create a common operating picture (COP) of the state of a pipeline, including identifying the high-risk areas. It allows companies to do preemptive maintenance vs. creating a maintenance schedule based on assumptions, or worse, waiting to do maintenance until something critical arises.
While companies cannot plan for everything, developing a COP can help them think critically when deciding how to mitigate environmental concerns, or even how to mitigate issues that could arise if a third party maliciously damages a pipeline for business or political reasons. Companies may also switch to a more tactical approach by only deploying systems like pigs and drones when a need is identified through the existing sensor system vs. a periodic maintenance cycle, further reducing costs.
Obtaining a real-time COP is the ultimate goal with an occasional augmentation to this with data from drones or pigs. This is where pressure, temperature and corrosion sensors come in. For day-to-day operations, monitoring a pipeline’s health in near real-time is made possible by installing intrinsic sensors regularly along the line.
With this setup, sensors are placed at stations or hubs where pressure, temperature, corrosion and flow rate are monitored. This enables companies to pull the data from that specific spot, aggregate it and send it out, allowing data to be analyzed for discrepancies and potential problems.
If a spike is noticed in one of the pressure monitors, it could suggest a clog in the section down the line from the sensor. Because data is collected from a specific position in the pipeline, engineers can easily and quickly locate the section of the line experiencing the problem and schedule maintenance to fix the issue. Alternatively, data showing a decrease in flow rate or pressure could indicate a leak.
When companies invest in sensors over longer periods of times, employees are able to begin recognizing the signs of a potential issue. Along with the prognostic capabilities of the system, employee recognition of these problems enables companies to modify operating schemes so that they are able to continue to function while using a failing part without it actually breaking, allowing time for the company to schedule maintenance and send someone out to fix or replace the part in question.
For instance, a SpeedCast customer was experiencing issues with a pump that was starting to vibrate. Due to the frequencies the pump was emitting, the customer could tell it was about to break down. To try to save the pump and decrease chances of a failure or spill, a decision was made to lower the pump’s output levels, decreasing the vibrations so that it would not fail until work could be done on it.
Because the issue was identified early, the pump continued to run while a maintenance plan was instituted. Though the company had to decrease the amount of oil it was sending through for a while, it would have lost even more time and money had the pump been left alone and allowed it to break.
There is a large amount of data available from sensors that companies may not receive as timely, if at all, with self-contained systems that need to be brought back for data offloading. With the near real-time data reporting, diagnostic and prognostic capabilities that come from this Internet of things (IoT) system, these tactics are being adopted more and more in the industry.
Subsea Pipelines
In the ocean, companies don’t have the opportunity for sensor integration as regularly as on land, so hub points become critical. Risks to pipelines also increase in the offshore sector and, similar to terrestrial pipelines, there are situations that you can’t monitor for or predict, including an anchor falling on the line.
Similar to the onshore arena, companies can launch pigs down the line to gather interior data for analysis. As with any self-contained system, these pigs must be retrieved before data can be offloaded. Where terrestrial pipelines use drones to periodically survey and collect data on the exterior of the line, subsea pipelines use autonomous underwater vehicles (AUVs).
AUVs are becoming more common in the oil and gas industry as the technology progresses. These vehicles require no operator intervention, allowing them to stay underwater for longer periods of time and travel farther distances. Like drones and pigs, these vehicles must return to their hub before data can be downloaded and processed.
Another underwater vehicle used to monitor and provide maintenance on subsea pipelines is a remotely operated vehicle (ROV). Unlike AUVs, ROVs are connected to a ship by a series of cables that allow the operator to send commands and signals to the hub. In addition to a video camera, lights and sonar systems, an ROV may have an articulating arm designed for retrieving objects, cutting lines and attaching hooks. They are often used as a temporary solution for issues surrounding environmental concerns of pipelines until a more permanent fix is found.
For incidents such as the Deepwater Horizon accident, an ROV can be deployed to monitor a damaged well with its video camera. These systems bring the data from the ocean floor back to the ship and then across a satellite link back to shore. Recently, SpeedCast and Oceaneering debuted a new system in which an ROV can be piloted from shore using satellite communications, further demonstrating how communications can remove costs from offshore operations.
Employee Safety
While real-time data monitoring and communication is essential to maintaining the health of a pipeline, it is also key to keeping employees safe on the worksite. Employees must be able to communicate with their home office in order to stay up-to-date on the situation if a pipeline is shut off or ready to be turned back on. This is made possible with satellite communications.
If there is an emergency, it is of the upmost importance employees be able to contact someone for help. For instance, if someone is injured while inspecting a pipeline, employees must be able to communicate in order to call for help or evacuate the area.
In addition to emergency communications, the enablement of communications and the use of drones, pigs, ROVs and AUVs mean that more data can be transferred and analyzed offsite, enabling companies to remove non-essential employees from rigs and other dangerous worksites. Increased monitoring leads to a reduction of long-term costs and an overall safer environment.
Author: Will Mudge is the Director of Engineering for SpeedCast. He has worked as a supplier to the oil and gas industry for more than 10 years on many onshore and offshore projects in the area of power and communication systems. He holds a BS degree in engineering physics from Embry-Riddle Aeronautical University and a U.S. patent for subsea high-voltage design.
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