Page 11 - Handbook Of Multiphase Flow Assurance

Examples of flow assurance problems 5

Flow assurance technology development also has its roots in PROCAP 1000, a technology
program executed by Petrobras from 1986 to 1991, comprised 109 multidisciplinary projects.
The cost of the program was 68 million USD. The projects developed under PROCAP 1000
gave rise to a significant part of the 251 patents obtained by Petrobras between 1987 and 1992.
It also allowed access to subsea oil fields in water deeper than 300 m which could not be ac-
cessed through diving, and the development of deepwater assets to a water depth of 1000 m,
which led to capital investment in fields such as Marlim and Albacora and multi-billion prof-
its from Petrobras' deepwater projects (Morais, 2013).

Examples of flow assurance problems

Solids such as hydrates shown in Fig. 1.2–1.4, wax or scale can form blockages and restrict
production. These solids can also affect mechanical integrity of a production system in mul-
tiple ways, such as erosion, rupture or collapse of pipelines. For example, hydrates can move
as projectiles. In a few instances offshore, a partly dissociated hydrate plug got launched from
a platform scraper receiver by gas pressurized behind the hydrate.
Ice blockages also can present a problem. In an onshore operation in Alaska, an ice block-
age formed in the smaller of the two flowlines operating in parallel due to differences in flow
distribution. Freezing caused a 24-in. long rupture as shown in Fig. 1.5 at the bottom of a
three-phase common line carrying a mixture of crude oil, produced water, and natural gas.
Corrosion caused a similar event in 2007 with imagery available at Alaska (2008). A 6-in.
long crack (about 1/8 in. wide at the center) formed in the flow line due to external corrosion.
Hydrates can also crush or collapse steel tubing such as a well production tubing as shown
in Fig. 1.6 in locations where water and gas accumulate at hydrate conditions in the same way
ice can crack an engine block if water is used as a coolant instead of an antifreeze.
A paraffin wax deposit can form when heavy hydrocarbon molecules with straight
chains of carbon atoms, also known as normal paraffins, precipitate on cold surfaces and

Fig. 1.2 Hydrate slush in a flowline after hydrate blockage was dissociated by depressurization in
an onshore Teapot Dome oil field.