Umbilical test rig improves efficiency
of testing & commissioning
O
ff the west
coast of Africa
investment
in subsea oil
exploration is growing year
on year, which is driving
the development of more
and more subsea structures
as part of the production
infrastructure.
New fields require the
installation of umbilical
systems to connect the
structures together and in
order to ensure efficient
and reliable performance,
the umbilical system
needs to be tested
and cleaned at regular
intervals. This process
has been streamlined with
the introduction of a new
test rig developed by RMI
Pressure Systems and
delivered to Duco UK as part
of an initiative to improve
the speed and reliability of
the commissioning process.
As the known reserves
of oil and gas diminish,
companies involved in the
industry continue to search
for and exploit potential
new sites. However this
is an extremely expensive
process, requiring huge
levels of investment which
must deliver more efficient
methods and equipment
to ensure a return on
investment.
Angola is the second-largest
oil producer in Sub-Saharan
Africa behind Nigeria,
and recent exploration
suggests that Angola’s
reserves may be larger
than initially estimated.
Successful exploration in
Angola’s pre-salt formations
continues to drive optimistic
oil production forecasts
for the country, with
further exploration to be
undertaken in deep water,
1200m and beyond. One of
the major players will invest
US$3 billion per year to the
end of the decade in Angola
alone.
With this investment
comes the requirement for
more reliable and efficient
equipment to ensure that
the development of each
site is as cost effective
as possible. Duco UK, a
leading manufacturer of
bespoke umbilical products
based in Newcastle, UK,
found that using their own
test equipment, rather
than contracting the work
out, was not only more
cost effective but also
provided more flexibility for
customers.
Due to the critical nature
of the systems and valves
which are controlled by
the hydraulic umbilicals
throughout the subsea
networks, it is essential
that the hydraulic fluid be
cleaned to the required
specifications. The lines
and connections must also
be regularly checked for
leakage to ensure that they
operate correctly and with
the necessary reliability
and efficiency. In order
to carry out the cleansing
and checking procedures a
test rig is required which is
capable of flushing out the
entire umbilical length and
submitting it to a pressure
test.
Having already developed
a new test rig for use in
offshore applications, RMI
was approached by Duco
UK to develop a similar
rig for onshore use, to
be delivered to another
division operating in Angola.
Having previously delivered
a unit designed to meet
the stringent offshore
regulations, RMI was able
to use this design as a basis
for the new test rig, which
would incorporate its Trimax
S250 high pressure pump.
The new test rig had to be
enclosed in a custom steel
framework which would
fit inside a standard cargo
container and allow for
it to be lifted by a whilst
also acting as protection
from occasional knocks.
The design needed to
deliver a system capable
of producing pressures up
to 15,000 psi (1,035 bar)
with flows between 3 - 15
US gallons/ min. (11 - 56
litres/min). Achieving these
figures would reduce the
overall time required to fill,
flush and pressure test the
umbilical system, which
in turn would reduce the
cost of installation and
commissioning.
RMI Pressure Systems has
developed a new test
rig for onshore/offshore
use which allows for
streamlined cleansing and
pressure testing in-situ.
130
PECM ssue 15
The completed test rig
provided this facility with
a much more efficient
pump, providing substantial
savings in time and money
to complete the testing and
flushing operations
The Trimax range of
crankshaft-driven,
reciprocating pumps
provides high efficiency
pumping at pressures up
to 1380 bar and flows
up to 610 litres/min,
delivered by three piston,
crankshaft driven, positive
displacement pumps.
Controlled by a Danfoss
variable frequency drive
(VFD) and Omron PLC, the
characteristics of the RMI
test rig allows it to be used
for both the filling / flushing
operation as well as the
high pressure testing; which
immediately reduces the
overall testing time, thereby
reducing overall costs.
All of the pumps are
fitted with a robust, fully
supported crankshaft with
con-rods assembled with
lead bronze big and small
end bearings. Extremely
high wear-resistant solid
ceramic plungers, combined
with Kevlar fibre seals,
provide long-lasting,
high-pressure sealing. All
pumps undergo a rigorous
testing programme prior to
dispatch, which includes oil
temperature and pressure
checks plus vibration
monitoring, as well as
verifying the normal pump
performance criteria.
www.rmipsl.com