Understanding Pipeline Integrity
Pipeline integrity is all about keeping pipelines operating properly throughout their life cycle. From design and construction to maintenance and inspection to decommissioning and retirement, pipeline integrity engineers work to ensure pipelines and their related components are reliable, sustainable, and safe throughout their service life.
Pipeline integrity can be maintained using a variety of different technologies and practices, and different pipeline integrity engineers will have their own specific procedures. In the end, though, the goal remains the same—to deliver reliable energy to market as efficiently and as safely as possible.
Planning and Building Pipelines
Focusing on Safety
Planning a pipeline route requires environmental consultants, engineers, and hundreds of others working in unison to find a route that is both environmentally safe and economically efficient. Many different factors, particularly the pipeline’s planned right-of-way and nearby environment, contribute to the pipeline route. Waterways and other vulnerable environmental features that need to be protected are identified and prepared for. Engineering assessments, valve placement, and how to protect and monitor for pipeline corrosion are also major considerations for pipeline design.
Corrosion Monitoring and Prevention
One of the largest threats to pipeline integrity is corrosion, making corrosion protection a critical aspect of pipeline planning, construction, and maintenance.
There are two primary processes for preventing pipeline corrosion that pipeline integrity engineers can consider when planning pipelines: protective coatings or cathodic protection. Protective coatings applied to the pipeline’s exterior can create a robust barrier to help prevent corrosion. Cathodic protection, on the other hand, uses an electrostatic current along the length of the pipeline to counter the corrosion reaction.
Pipeline Geohazard Management
Design, operation, and management of pipeline integrity is a complicated process. When you include the complex challenges arising from difficult terrain and geologic conditions into the mix, the consequences and associated risks are generally higher for geohazards. Regulatory bodies recognize these are very serious and complex challenges with recent bulletins published by the Pipeline and Hazardous Materials Safety Administration [PHMSA] and the Alberta Energy Regulator [AER] on the topic outlining new and more comprehensive practices.
As critical pipeline infrastructure ages, its strain capacity can diminish due to cracking and corrosion. With global expansion of pipelines into more difficult terrains, along with the unpredictable environmental conditions created by climate change, the potential exists for failure events to significantly increase. Proactive geohazard management through monitoring and intervention has become essential and forward-thinking organizations are adopting new technologies becoming available.
Gas Transmission Integrity Management Programs (IMP) that include geohazard considerations have become more standard in within the past 5 to 10 years. Regulators also now require that programs address geohazards considering weather and outside forces. But the regulations do not provide details on program designs, and operators are highly variable in how they address the geohards threat to pipeline integrity.
Geohazards are natural processes of a geologic, geomorphologic, or hydrogeologic nature – they naturally vary in a myriad of ways based on regional terrain.
|Regional Terrain||Common Geohazards|
Peatlands and Organic
Landslides, slope creep, karst, subsidence, mining
Vertical scour, lateral scour, channel migration, flooding
Headcuts, downcutting, ROW backfill, erodible soils
Faults, liquefaction, lateral spreading, tsunami
Once a pipeline is constructed and in use, it becomes essential to monitor it for geohazards, corrosion and leaks. There are plenty of monitoring practices available to pipeline operators, with most organizations deploying multiple approaches and systems to monitor the entire pipeline and meet regulatory requirements.
Geohazard Remote Monitoring Systems
A significant potential risk exists when critical pipeline projects are constructed in environmentally sensitive areas where geotechnical or seismic hazards are present. Having direct pipeline structural integrity data available to the operator on an ongoing basis provides an unparalleled understanding of the ongoing health of the asset being monitored. Geohazard monitoring systems and sensors have historically been a serious challenge to include in programs due to the extremely high cost to deploy as well as maintain. Today there are much more accessible options with remote monitoring interfaces that can be tailored to the specific application requirements, allowing for monitoring of localised conditions on new or existing lines or monitor an entire pipeline network. The data can be delivered wirelessly in a cost effective manner to multiple stakeholders in near real-time, minimizing the risk of events spiraling out of control. Data can then be interpreted, analyzed, and visualized to ensure that appropriate responses can be developed in a timely manner.
The most basic form of monitoring, external evaluation is exactly what it sounds like; maintenance and inspection crews patrol the pipeline performing visual inspections of the pipeline route. These ground-based crews may be supplemented by low-flying aircraft and drones that can evaluate pipelines from above. Video surveillance is another option, and cameras fitted with temperature sensors that can watch for evidence of leaking pipelines is another common monitoring option.
Hydrocarbon Vapour Detection
Hydrocarbon vapour detection is a monitoring option that uses specialized cameras to detect the unique hyperspectral signature of evaporating hydrocarbons. These specialized cameras can be fitted to aerial vehicles such as drones, or permanently deployed to river crossings and other crucial remote sites. They are capable of detecting miniscule amounts of evaporated hydrocarbons up to two kilometers away, meaning hyperspectral cameras can locate even the tiniest pipeline leak.
Fiber Optic Monitoring
When pipelines leak, they often cause unexpected fluctuations in the temperature of the surrounding soil. Fiber optic monitoring involves placing fiber optic cables (capable of transmitting information at up to 300,000 km/second) along the pipeline to sense these changes. Fiber optic cables can also detect the acoustic vibrations created by leaking pipes, triggering alarms in the control room when detecting those vibrations or any unexpected or dramatic changes in soil temperature.
The “Pressure Wave” Method
When a pipeline begins losing pressure unexpectedly, the pressure loss is often caused by a leak. A leaking pipeline produces a rarefaction wave kind of like the ripples made when tossing a pebble into a pond. Sensors capable of detecting these “pressure waves” can be used to trigger alarms when pipeline pressure drops, alerting control room operators to the potential problem.
Maintenance and Inspection
Proper monitoring and maintenance of a pipeline involves tracking the integrity of the entire length of the pipeline. Modern technology, wireless sensing platforms, and powerful software have made pipeline monitoring and inspections significantly easier, and even small leaks or changes in conditions can be quickly detected. These programs track each pipeline segment’s pressure, temperature, and flow rate performance during normal use, then use that information to create a profile. The pipeline can then be inspected or, if necessary, shut down when sensors inside the pipeline detect a change in any of those parameters.
An Essential Process
Ensuring the integrity of pipelines has always been an essential aspect of pipeline operations. Regular monitoring and inspections not only help ensure energy is delivered safely and efficiently around the world, but also help protect the environment and the operator from damaging spills or costly leaks. While monitoring options were limited and expensive in the past, the advancement of technology and new processes has given operators more choices than ever to keep their pipelines in optimal operating condition.