Getting to the root of complicated pipeline routes
Pipelines are the most efficient means of transporting large quantities of fuel, in part because of the careful consideration that goes into pipeline route planning.
The design phase of a pipeline route typically dictates that the pipeline follows the shortest route possible. As well as reducing the amount of time it takes to transport product from A to B locations, this also reduces the cost of materials and construction or the need for additional pumps or compressor stations. Additional considerations for pipeline routing include:
- Minimizing intersections with roads, railways and water sources
- Reducing the number of bends, or limiting the angle of bends to comply with region specific rulings
- Avoid densely populated areas where possible
- Utilizing existing utility infrastructure, such as pipeline right of way, for parallel routing
- Avoiding areas of environmental significance
- Avoiding hillsides
- Ensuring access to the pipeline is possible for transporting materials, construction accessibility, and maintenance and emergency response1
Newly available information from route surveys, protests from residents in the surrounding area and various other factors often mean it’s not always possible to achieve the above outcomes in a pipeline route. A recent example can be seen in Canada where a pipeline route’s expansion has been continually delayed and adjusted due to claims that its construction will result in environmental violations and disturb sacred indigenous land.2,3
It’s not uncommon to see pipelines in river crossings, urban areas, with significant elevation changes and various other complications in a pipeline route. For a multiproduct pipeline requiring batch tracking, this can create a range of challenges.
In this blog, Principal Simulation Engineer Giancarlo Milano discusses the challenges of batch tracking on difficult pipeline routes and how solutions like Atmos Batch are best placed to provide support in these scenarios.
What is batch tracking?
In a liquid pipeline there can be different types of products going to different locations with varying ownerships. There can also be varying qualities of the same product, all going to different customers. Each fixed volume of product contained with a start and end position within a pipeline can be described as a batch.
Batch tracking is the process of monitoring how much product volume is injected into the pipeline versus how much product is delivered out of the pipeline. It accurately forecasts where batches start and end, the size of batch volume and their Estimated Time of Arrival (ETA).
Atmos Batch is a module available within Atmos Simulation (SIM) Suite. Figure 1 shows an example of how the batch tracking process can be fulfilled.
Figure 1: Atmos Batch showing the progress of batches through the pipeline
With Atmos Batch, operators know for certain the head and tail location of every batch in a multiproduct pipeline and can prepare ahead of time to swing valves at the exact moment when a batch arrives at a station, delivering product to the right storage tank or to an end-customer with minimal contamination of products with different qualities.
Batches can be represented on a map via a graphical user interface (GUI), which connects to Atmos Batch’s simulation engine to provide real-time status for batches (see Figure 2).
Figure 2: Atmos Batch’s GUI representing batch locations on two separate pipelines. Each color inside the pipelines represents a different batch/product
Using the GUI operators can make changes on the go to modify batch details such as size, location, injection and delivery nomination, product information, creating reports and more.
Challenges can arise for a batch tracking system when a pipeline route faces large elevation changes caused by hilly or mountainous terrain. Without a batch tracking software that can take these variables into account, determining the head and tail location of a batch could quickly become a guessing game with an increased risk of inaccuracies in locations, and therefore ETAs.
Pipelines with elevation changes and slack
Areas with varying topography can impact the elevation profile of a pipeline, which can cause slack flow, also known as column separation. This occurs when the product experiences a change in density and the liquid’s pressure falls below its vapor pressure, causing a phase change in the fluid from liquid to gas. Here are some examples where we’ve overcome the challenge of elevation changes on pipeline route using Atmos batch tracking software.
Example pipeline 1: Mountain crossing pipeline in Canada
A pipeline traversing the Canadian Rockies transports crude oil and refined liquid products from one region in Canada to another.
Some sections of the pipeline are highly compressed, while others are in slack conditions. To accommodate for these conditions, Atmos Batch is used to calculate packing and unpacking in these sections. Atmos Batch is set up in the live environment to track the volume entering and leaving each section of the pipeline which resulted in an ETA error of +/- 15 minutes on the 1,150 km pipeline with drastic elevation changes.
This empirical approach to batch tracking negates the need for a full model of the liquid hydraulics of the pipeline.4
Figure 3: This empirical approach has proven successful as a feature of Atmos Batch that many batch pipeline operators prefer to use. The accumulated inflow and outflow is totalized as liquid volume into and out of a region (top) and that is used to deduce the empty volume (bottom) which is in reality occupied by vapor
Example pipeline 2: Compressible batches over mountains in Latin America
A liquid transportation network in Latin America transports around 25,000 barrels per day of reconstituted crude oil through a terminal in a neighboring country. It also supplies a remote region with liquefied petroleum gas, but to achieve this, compressible batches are pumped across mountainous terrain.
The presence of compressible batches in this pipeline leaves it vulnerable to column separation at many points throughout its route, which is when sections of the pipeline become blocked or isolated due to the formation of vapor pockets (see Figure 4). This behavior can disrupt the flow of product and makes batch tracking a challenge because it’s difficult to predict actual volumes of inline batches and where the gaps are.
In the event of column separation, batch detectors at stations along the pipeline’s route can provide batch tracking software like Atmos Batch with the necessary information to make accurate predictions of batch and pig arrival times.5
Figure 4: The head profile along this pipeline shows where the pressure has fallen below the vapor pressure of the fluid batch, so slack flow occurs starting at the top of the first big mountain peak and again at several smaller peaks downstream
Atmos Batch is best placed for decomplicating pipeline routes
A range of challenges are presented when a pipeline route has complications such as elevation changes or river crossings. Batch tracking software like Atmos Batch is an essential tool for running multi-product or multi-crude pipelines where a specific batch of a product type needs to be tracked down the line efficiently and cost effectively.
With an accurate visual display that reports batch details and other valuable information to the commercial department, Atmos Batch helps ensure the correct product goes to the right end user and isn’t contaminated in the process, helping optimize for sales revenue.
Learn more about Atmos Batch
References
1 https://epcmholdings.com/pipeline-routing-consideration/
2 https://westcoastnow.ca/2023/11/29/trans-mountain-pipeline-resumes-after-environmental-violations/
3 https://thenarwhal.ca/trans-mountain-launch-indigenous-rights/
4 https://www.atmosi.com/en/resources/books/the-atmos-book-of-pipeline-simulation-chapter-11/
5 https://www.atmosi.com/en/resources/books/the-atmos-book-of-pipeline-simulation-chapter-eight/