Types of pipelines: gathering, feeder, transmission and distribution
When people talk about "pipelines" they usually mean the large lines that make the news. In fact, oil and natural gas pass through several different kinds of pipe between the well and the end user, and each kind is built, operated and regulated differently. Natural Resources Canada counts about 825,000 km of transmission, gathering and distribution pipelines in Canada.
The original page How do pipelines work? gives the three-step overview. This guide goes through each type in more detail.
At a glance
| Type | What it does | Typical size and pressure |
|---|---|---|
| Flowlines | Connect individual wells to nearby equipment | Small diameter, pressure depends on the well |
| Gathering lines | Collect oil and gas from many wells and carry it to processing plants, batteries or storage | Small to medium diameter |
| Feeder lines | Move processed products from plants and terminals into transmission systems | Medium diameter |
| Transmission lines | Carry crude oil, natural gas or refined products long distances | Large diameter, high pressure |
| Distribution lines | Deliver natural gas to homes and businesses | Small diameter, lower pressure |
Flowlines and gathering lines
Every oil or gas well needs a way to move what it produces. A flowline connects the wellhead to a battery or separator nearby, where water, oil and gas are separated. Gathering lines then collect production from many wells and carry it to processing plants, oil batteries or storage. They are most common in producing regions such as Alberta, Saskatchewan and northeastern British Columbia, where they form dense local networks.
Gathering systems can carry raw products, including sour gas that contains hydrogen sulphide, or mixtures of oil, gas and water. Because they lie within a single province, they are regulated provincially, for example by the Alberta Energy Regulator or the BC Energy Regulator.
Feeder lines
Once natural gas has been processed, or crude oil has been treated or blended, feeder pipelines move it to the start of a transmission system. Feeder lines are the link between producing areas and the long-distance network.
Transmission pipelines
Transmission pipelines are the energy highways. They are large-diameter steel lines operating at high pressure that move products across provinces and into the United States. Liquids transmission lines use pump stations to move crude oil and refined products; gas transmission lines use compressor stations to keep gas moving. Many carry products in batches, with different grades shipped one after another through the same pipe.
Transmission lines that cross a provincial or national border are regulated by the Canada Energy Regulator (CER). The CER regulates over 73,000 km of pipelines, including about 48,000 km of gas pipelines and 19,000 km of liquids pipelines. Our guide to oil pipelines in Canada covers the largest liquids systems, and the original pages on natural gas lines and liquids lines explain how each works.
Transmission pipelines run in dedicated rights-of-way. Within 30 metres of a federally regulated line, the CER's damage prevention rules require a locate and the company's consent before ground disturbance; see Click Before You Dig.
Distribution pipelines
Distribution pipelines are the final step for natural gas. Local gas utilities take gas from transmission lines at "gate" or regulating stations, reduce the pressure, add odorant, and send it through networks of mains under streets. From the mains, service lines run to the meter on each building.
Distribution systems are regulated provincially; in Ontario, for example, by the Ontario Energy Board and the Technical Standards and Safety Authority. Their pipe is smaller and operates at lower pressure than transmission pipe, but because it runs through neighbourhoods it is the type most often hit during digging. Our guides on how deep gas lines are buried and what natural gas smells like cover the safety side.
Pipelines by product
Pipelines can also be grouped by what they carry:
- Natural gas pipelines carry methane-rich gas, sometimes with natural gas liquids.
- Crude oil pipelines carry light, medium and heavy crude, including diluted bitumen from the oil sands.
- Refined products pipelines carry gasoline, diesel and jet fuel from refineries to terminals.
- Natural gas liquids (NGL) pipelines carry products such as ethane, propane and butane.
- Other pipelines carry carbon dioxide for enhanced oil recovery or storage, water, or, increasingly in pilot projects, hydrogen blends.
For an overview of products, see the original page What products do pipelines transport?
Why the differences matter
The type of pipeline determines how it is designed, how often it is inspected, which regulator oversees it, and what precautions apply near it. A homeowner planting a hedge is most likely to meet a distribution service line; a farmer tiling a field may cross a transmission line or a gathering line. In every case the first step is the same: request a locate before you dig, and read any pipeline markers nearby for the operator's emergency number.
Sources
- Natural Resources Canada, Pipeline safety regimes in Canada
- Canada Energy Regulator, Canada's Pipeline System 2021
- Canada Energy Regulator, Damage prevention
Frequently asked questions
What are the four main types of pipelines?
Gathering lines, feeder lines, transmission lines and distribution lines. Together they move oil and natural gas from wells to processing plants, then over long distances, and finally to homes and businesses.
What is the difference between a transmission and a distribution pipeline?
Transmission pipelines are large-diameter, high-pressure lines that move oil or gas long distances across provinces and countries. Distribution pipelines are the smaller, lower-pressure networks local gas utilities use to deliver natural gas to individual customers in towns and cities.
What is a flowline?
A flowline is a small pipe that connects a single well to nearby equipment such as a battery, separator or gathering system. Flowlines are the first step in moving oil and gas away from the wellhead.
Are all pipelines regulated the same way?
No. Pipelines that cross a provincial or national border are regulated by the Canada Energy Regulator. Pipelines that stay inside one province, including most gathering and distribution lines, are regulated by that province.