Page 23 - Petroleum Production Engineering, A Computer-Assisted Approach

Guo, Boyun / Computer Assited Petroleum Production Engg 0750682701_chap01 Final Proof page 11 4.1.2007 6:12pm Compositor Name: SJoearun

PETROLEUM PRODUCTION SYSTEM 1/11
gal compressor consists of a housing with flow passages, a most economical means of large-scale overland transpor-
rotating shaft on which the impeller is mounted, bearings, tation for crude oil, natural gas, and their products, clearly
and seals to prevent gas from escaping along the shaft. superior to rail and truck transportation over competing
Centrifugal compressors have few moving parts because routes, given large quantities to be moved on a regular
only the impeller and shaft rotate. Thus, its efficiency is basis. Transporting petroleum fluids with pipelines is
high and lubrication oil consumption and maintenance a continuous and reliable operation. Pipelines have
costs are low. Cooling water is normally unnecessary be- demonstrated an ability to adapt to a wide variety of
cause of lower compression ratio and less friction loss. environments including remote areas and hostile environ-
Compression rates of centrifugal compressors are lower ments. With very minor exceptions, largely due to local
because of the absence of positive displacement. Centrifu- peculiarities, most refineries are served by one or more
gal compressors compress gas using centrifugal force. In pipelines, because of their superior flexibility to the
this type of compressor, work is done on the gas by an alternatives.
impeller. Gas is then discharged at a high velocity into a Figure 1.16 shows applications of pipelines in offshore
diffuser where the velocity is reduced and its kinetic energy operations. It indicates flowlines transporting oil and/or
is converted to static pressure. Unlike reciprocating com- gas from satellite subsea wells to subsea manifolds, flow-
pressors, all this is done without confinement and physical lines transporting oil and/or gas from subsea manifolds to
squeezing. Centrifugal compressors with relatively unre- production facility platforms, infield flowlines transport-
stricted passages and continuous flow are inherently high- ing oil and/or gas from between production facility plat-
capacity, low-pressure ratio machines that adapt easily to forms, and export pipelines transporting oil and/or gas
series arrangements within a station. In this way, each from production facility platforms to shore.
compressor is required to develop only part of the station The pipelines are sized to handle the expected pressure
compression ratio. Typically, the volume is more than and fluid flow. To ensure desired flow rate of product,
100,000 cfm and discharge pressure is up to 100 psig. pipeline size varies significantly from project to project. To
More information about different types of compressors is contain the pressures, wall thicknesses of the pipelines
3
1
provided in Chapter 11. range from ⁄ 8 inch to 1 ⁄ 2 inch. More information about
pipelines is provided in Chapter 11.
1.7 Pipelines
1.8 Safety Control System
The first pipeline was built in the United States in 1859
to transport crude oil (Wolbert, 1952). Through the one The purpose of safety systems is to protect personnel, the
and half century of pipeline operating practice, the petro- environment, and the facility. The major objective of the
leum industry has proven that pipelines are by far the safety system is to prevent the release of hydrocarbons

Expansion
Tie-in
Spoolpiece
Existing
Line
Pipeline To Shore
Crossing

Infield
Flowline
Riser
Satellite
Subsea
Wells
Tie-in
Subsea Manifold Export Pipeline

Flowlines
(several can be
bundled)

Flowlines
Figure 1.16 Uses of offshore pipelines. (Guo et al., 2005.)