TWO PHASE GAS-LIQUID PIPELINE DESIGN

Pipelines are the most common way of transporting oil or gas in oil and gas industry.
A pipeline is all parts of the physical facility through which liquids or gases such as
crude oil and natural gas are moved, usually over long distances between a producing
region and a local distribution system. A pipeline is like any other flowline. The
main differences are that pipelines are long and continuously welded, they have a
minimum number of curves, they have no sharp bends, and they are most often either
buried or otherwise inaccessible due to their location over the majority of their
length. These differences mean that small sections of pipeline are not easily removed
for maintenance and consequently great care is taken to prevent problems arising in
the first place. A pipeline is extremely expensive to lay, and in the case of offshore
pipelines, costs in the order of several million pounds per subsea mile have been
encountered. Maintenance on pipelines is also expensive but this expenditure is
necessary since, regardless of the expense, pipelines frequently form the most
efficient and cost-effective method of transporting the quantifies of oil or gas
produced. Multi-phase transportation is currently receiving much attention troughout
the oil and gas industry. The combined transport of hydrocarbon liquids and gases
can offer significant economic savings over conventional, local, platform based
separation facilities. Much of fluid data used to design two-phase pipeline have been
determined experimentally and through test made in operationg two-phase pipelines.
Two-phase pipeline design is a subject on which research and testing continue, and
sophisticated computer programs can predict flow conditions and pressure drop more
accurately. A number of different correlations have been developed for two-phase
pipeline design. Pipe tlow simulation is used to optimize and verify design and to
throw light on various operational issues and also for training engineers and
operators. This paper is an approach to minimize the operation and maintenance cost
by selecting the optimum pipeline size and sizing a slug catcher between the outlet of
the pipeline and the processing equipment. PIPESIM is used to run the simulation
and compute the complex calculation involved in designing the pipeline size and
sizing the slug catcher.