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UNIT 6
OIL AND GAS COLLECTIONING AND
PREPATION SYSYTEMS
STORAGE, DISTRIBUTION AND PROCESSING OF OIL
AND GAS

The oil and gas process is the process equipment that takes
the product from the wellhead manifolds and delivers stabilized
marketable products, in the form of Crude Oil, Condensate or Gas.
Components of the process also exist to test products and clean
waste products such as produced water.
Our example process, for the Norsk Hydro Njord floater is
shown on the next page. This is a medium size platform with one
production train and a production of 40- 45.000 barrels per day
(bpd). This is actual production, after separation of water and gas.
The associated gas and is used for on board power generation and
gas reinjection. There is only one separation and gas compression
train. The water is treated and released (it could also have been
reinjected). This process is quite representative for hundreds of
similar size installations, and only more complete gas treatment
and gas export is missing to form a complete gas production
facility, Njord sends the oil via a short pipeline to a nearby storage
floater. On gravity base platforms, FPSO (Floating Production and
Storage Operations) and onshore plants this storage will be a part
of the main installation if the oil is not piped out directly [16].

Pipelines and Risers
This facility uses Subsea production wells. The typical
High Pressure (HP) wellhead at the bottom right, with its
Christmas tree and choke, is located on the sea bottom. A
production riser (offshore) or gathering line (onshore) brings the
well flow into the manifolds. As the reservoir is produced, wells
may fall in pressure and become Low Pressure (LP) wells.
This line may include several check valves. The choke,
master and wing valves are relatively slow, therefore in case of
production shutdown, pressure before the first closed sectioning
valve will rise to the maximum wellhead pressure before these

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