How C-FER is Addressing Key Pipeline Engineering Challenges
The Canadian pipeline industry works together to address key industry challenges through industry-led organizations such as Energy Connections Canada and the Canadian Gas Association.
In the USA, similar pipeline organizations include Pipeline Research Council International, Interstate Natural Gas Association of America, and American Gas Association. Internationally, the European Pipeline Research Group and Australia’s Future Fuels CRC fill these roles.
The Challenges
Geohazards
Geohazards are a type of pipeline integrity threat in which ground movement induces stresses and strains on a pipeline. In many geohazard scenarios, the ground movement can be sufficient to permanently deform (or yield) the pipe. This can lead to loss of containment or loss of serviceability.
Typical geohazards include:
Unstable slopes in mountainous areas or in river valleys
Ground freeze/thaw cycles and permafrost regions
Bank erosion at river crossings
Earthquakes and tectonic fault movements
Helping understand the impact of ground movements
C-FER is working with industry to estimate the impact of ground movements on pipeline performance. We use advanced structural modelling techniques that consider the properties of the pipe and the surrounding soil, and the interaction between the two.
Traditional pipeline design methods that limit the stress on the pipe cannot be used for assessing geohazards. In these instances, the pipeline design is governed by how much the soil moves, and how much strain it causes in the pipe. This is termed the strain demand.
Geohazard characteristics, such as soil movement patterns, soil movement rates, and soil properties, are uncertain and vary depending on the location along the pipeline and over time.
We can combine site-specific data, such as inertial measurement unit (IMU) data, soil properties (e.g. borehole logs), inclinometers, and LiDAR, with available structural modelling methods to predict present and future strain demand on the pipeline.
Strain demand predictions can then be combined with appropriate strain capacity models and relevant pipeline attributes to evaluate the integrity and safety of the pipeline under various geohazard conditions.
C-FER can help understand the impact of these geohazards by applying probabilistic design methods to account for the various sources of parameter uncertainty and estimate a probability of failure.
Leak Dectection
Pipeline systems all use precision monitoring systems to detect leaks. Computational pipeline monitoring (CPM) systems measure the flow rate, pressure, and temperature at multiple points along a pipeline. These systems compare the measurements to fluid dynamics models of the flow to identify any discrepancies that might be due to a leak.
The CPM model is extremely complex. Models have to consider transient flow conditions with compressible fluid and, where batching different products, different fluid properties, which makes it difficult to precisely know what the pressure, temperature, and flow conditions should be at any specific time.
In addition, the instrumentation system can only measure the operating conditions to a specific level of accuracy and precision, introducing more uncertainties into the fluid dynamics model results.
Consequently, CPM systems may not be able to detect small leaks in some of the more complex pipeline systems.
To augment CPM leak detection systems, a variety of other leak detection technologies can be installed on or near the pipeline including:
Distributed Temperature System (DTS): uses a fibre optic cable buried adjacent to the pipe to monitor temperature changes along the pipeline, such as reduced temperature on gas lines caused by cooling as the released gas expands or increased temperature where warm liquid petroleum products leak into the cooler surrounding soil
Distributed Acoustic System (DAS): uses a fibre optic cable buried adjacent to the pipeline to monitor for sounds associated with gas or liquid leaking from small corrosion holes or cracks in the pipeline
Vapour Sensing Systems: collect air samples around the pipeline and analyze the sample to determine if any hydrocarbon products are present
Hydrocarbon Sensing Cables and Sensors: buried with the pipeline and signal when they come into contact with a hydrocarbon
Negative Pressure Wave Systems: detect a pressure pulse that travels along a pipeline when a leak starts
Encapsulated Instruments: flow freely with the liquid in the pipeline and measure changes in pressure, temperature, flow velocity, and acoustic signals that are associated with leaks
Airborne or Satellite-based Systems: use air sampling, laser absorption, hyperspectral imaging (including infrared) to detect leaks
C-FER Yourself
C-FER operates the ELDER system, a liquid pipeline leak simulator that replicates liquid hydrocarbon leaks into soil at full-scale.
This system was used to assess over 20 different external leak detection technologies through a Joint Industry Project.
This work led to C-FER working with the US pipeline regulator PHMSA to develop a guideline for how to assess the performance of external pipeline systems
Calibration and verification of these leak detection systems are difficult since actual pipeline leaks are rare, so there is little historical data available.
Also, environmental regulations do not allow releases of hydrocarbon liquids into the environment
C-FER Yourself
C-FER assembles Joint Industry Projects to test the performance of various leak detection systems using real products in controlled testing conditions. These projects are typically funded by the pipeline operators with additional funding support through provincial and federal grants. These projects help:
- Pipeline operators to find the best available technologies for their application
- Equipment vendors to improve their product using the raw data they collect during the controlled releases
- Engineering and construction companies to develop best practices for deploying the technologies
- Regulators to establish guidelines for how to demonstrate the effectiveness and reliability of proposed leak detection systems
Integrity Management
Like any other asset, pipelines need to be regularly monitored, inspected, and repaired to ensure reliable and safe operation. Operators use sophisticated inline inspection (ILI) tools to survey the pipeline for defects such as cracks, dents, gouges, buckles, and corrosion wall loss that could reduce the pressure capacity of the pipeline.
C-FER helps operators use probabilistic analysis methods to estimate how defects affect the remaining burst strength of the pipe. Integrity management software such as C-FER’s PIRAMID account for the accuracy and resolution of the ILI tool, as well as uncertainties in the pipe material properties and wall thickness. The result is a robust estimate of the probability of failure of the pipeline under normal operating conditions.
Considering other threats
Integrity assessments also consider other threats as defined in ASME/ANSI B31.8S Gas Transmission and Distribution Piping Systems that could impact pipeline performance.
The probability of failure for each of these threats is matched with models that estimate the consequences of the specific failure type in terms of the impact on life safety, environmental damage and economic impacts of interrupted operation and lost product.
C-FER uses a quantitative risk assessment approach that combines pipeline failure consequences and probabilities of failure to estimate the risk at different points along the pipeline. This information can be used to prioritize further inspection and maintenance activities to ensure the safe and reliable operation of the pipeline.
When warranted, defects are inspected further by conducting an integrity dig to expose the pipe. In-ditch measurements during the integrity dig such as ultrasonic inspection or physical measurements are used to determine if the defect can be repaired or if the segment of pipe needs to be replaced. Various methods are used for repairing defects, including non-welded external sleeves that are installed to strengthen the pipe and restore its pressure carrying capacity.
C-FER Yourself
PIRAMID can assist you in all aspects of evaluating and managing pipeline integrity, including:
- Assessing pipeline risk
- Evaluating factors that impact pipeline risk
- Managing defects and planning mitigation activities
- Communicating risk results to stakeholders
C-FER Yourself
C-FER, in partnership with four major pipeline operators, is working to identify and evaluate the best composite or hybrid repair technologies for restoring circumferential cracks on pipelines.
For example, C-FER has conducted full-scale laboratory tests to assess the performance of non-welded sleeves to repair circumferential cracks in girth welds.
C-FER Yourself
C-FER is working closely with oil and gas pipeline operators to independently validate technologies for inspecting and repairing high-pressure pipelines and wells.
We offer side-by-side comparisons of inspection tool performance in controlled, full-scale tests.
Spill Preparedness
The leading cause of leaks from transmission pipelines is damage caused by third parties that inadvertently hit the pipeline while doing other work, such as farming and construction. Consequently, pipeline operators must be prepared to respond to leaks resulting in spills of liquid hydrocarbons to the environment.
In Canada, pipeline operators ensure that they have access to a collection of spill response equipment by forming spill response co-ops such as Western Canadian Spill Services, Eastern Canada Response Corporation (ECRC), and Western Canada Marine Response Corporation.
Responding to spills on inland waterways poses significant challenges due to the difficulty in accessing remote areas and the huge variability in spill conditions, such as river flow rates during floods, spills in ice-covered water, changes in spilled oil properties in cold temperature, interaction of spilled hydrocarbons with suspended solids in the water, and with plants along shorelines and riverbanks.
C-FER has constructed the Inland Waterway Simulator (IWS) to help equipment vendors and pipeline operators assess and improve the performance of spill response technologies, including:
- Oil detection technologies for both floating and submerged/sunk oil in flowing water
- Spill containment technologies such as booms and bubble curtains
- Oil recovery technologies such as skimmers and adsorbers
C-FER Yourself
C-FER’s Inland Waterway Simulator is a large-scale river channel testing facility capable of simulating spills of various products under realistic flow conditions.
Tests in the Inland Waterway Simulator will support the development and improvement of new and existing technologies used to monitor or manage inland waterways.
Want to learn more about the Canadian Pipeline industry?
Contributor
Brian Wagg, MSc, PEng.
Director, Testing Services
With over 35 years with C-FER, Brian Wagg’s current focus is on applying C-FER’s analytical and full-scale testing capabilities to projects in clean energy including CCUS, hydrogen, geothermal and small modular nuclear reactors.
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