Oil and gas production handbook An introduction to oil ... - ABB Group

5.4 Pipelines
Pipeline installations consist of driving compressors and pumps, valve
stations, pig receive/launch facilities, where the pig is used for cleaning or
inspecting the pipeline. A pipeline SCADA system and pipeline management
system is required to control and operate the pipeline.
5.4.1 Pipeline terminal
Pipelines transport gas or
liquid, and are fed from the
high pressure compressors or
pumps.
The pipeline terminal includes
termination systems for the
pipeline. A pig launcher and
receiver is a minimum
requirement, allowing insertion
of a pipeline pigging device
used to clean or inspect the
pipeline on the inside. Essentially, it is a large chamber that can be
pressurized and purged to insert and remove the pig or scraper without
depressurizing the pipeline.
The pig is often driven by pipeline flow, either directly or through a pump or
turbine arrangement that also drives wheels that roll against the walls and
mechanisms to rotate brushes and other scraping mechanisms. Intelligent
pigs also contain instrumentation for remote control and cameras, etc.
5.4.2 Gas Pipelines, compressor and valve stations
One or more compressor stations are needed to keep the required gas flow
in the pipeline. Internal friction will cause a pressure drop along the pipeline
that increases with flow. Thus, the starting pressure must be high enough to
maintain design capacity flow up to the final terminal. If this is not practically
possible, additional compressor stations are needed along the total length.
Typical starting pressure is about 150-250 bar (15-25 MPa). The final
pressure can be as low as 50 bar (5 MPa) at the pipeline terminal end.
The compressors are driven in the same way as explained in the
compressor chapter under production (see Chapter 4.3.3).
67