Oil pipelines are made from steel or plastic tubes with inner diameter typically from 0,1 m to 1,2 m (about 4 to 48 inches). Most pipelines are buried at a typical depth of about 2 m. Pump stations along the pipeline keep the oil in motion with a flow speed of about 1 to 6 m/s.Multi-product pipelines are used to transport two or more different products in sequence in the same pipeline. Usually there is no physical separation between these different products in multi-product pipelines.
Crude oil contains varying amounts of wax or paraffin, and in colder climates a wax buildup may occur within a pipeline. Often these pipelines are inspected and cleaned using inspection gauges pigs, also known as 'Go-devils'. These devices are launched from pig-launcher stations and travel through the pipeline to be recieved at any other station down-stream, cleaning wax deposits and material that may have accumulated inside the line.
The main elements of a pipeline system are: Initial injection station, compressor stations, partial delivery stations, block valve station, regulator station and the final delivery station. Typical types of pipelines are:
- Gathering pipelines
- Transportation pipelines
- Distribution pipelines