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DEEP OFFSHORE TECHNOLOGY INTERNATIONAL
Advances in Subsea and Deepwater Pipeline Pre-commissioning
John Grover
BJ Process & Pipeline Services

Introduction
The increasing number of subsea and deepwater developments brings new
challenges where there are no surface connections to the pipeline available
for pipeline testing and pre-commissioning.
Once constructed / installed such subsea and deepwater systems still have
to undergo certain pre-commissioning and commissioning operations, from
initial flooding, gauging & testing up to final start up.

Global Market Overview
Offshore pipeline installation forecasts show significant growth in both water
depth and length, however shallow water lines still dominant
• Significant growth in WD of 100m+
• Growth in NPS 16 to 24 range reflects subsea developments
• Regional growth in Australia, Indonesia, Malaysia and India
• Growing trend of smaller finds in deeper waters
• Develop several smaller discoveries together
Source – Infield Systems Ltd

Objective
• Flooding and pigging subsea pipelines using a
Remote Flooding Module
• Pressurisation using subsea hydrotest oump
• Use of smart gauge tools (SGT) to gauge
pipelines – allows the gauging of lines with
reduced bore & testing without pig recovery.
• Use of subsea data loggers to record
pressures and temperatures
• Use of systems to transmit this data to surface
real-time during the test period
• A look at the next generation of technologies
for deepwater pipeline pre-commissioning
Whilst the provision of such services in shallow water and topside-to-topside
developments is routinely achieved, providing the same services at water depths in
excess of 1,000m poses many challenges. In this paper we shall review the unique
challenges in providing such services deepwater, and then review current / planned
technologies including:

Oil Pipeline Pre-commissioning
Fill line with
treated &
filtered water
Run sufficient
cleaning pigs to meet
agreed cleanliness
Prove internal bore
by running a gauge
pig of caliper tool
Perform
hydrostatic
strength test
Optional
caliper survey
/ OOS survey
Line ready for
commissioning
/ lay up
1 2 3
4 5 6

Gas Pipeline Pre-commissioning
Steps 1 to 4 as
for oil pipelines
– line tested
Dewater & swab line
to remove bulk water
– run desal slug
Dry line to an
agreed “dewpoint”
using dry air or
vacuum
Optional
caliper survey
/ OOS survey
Line ready for
commissioning
/ lay up
1 2 3
4 5 6Purge & pack
the line with
nitrogen gas
April 4th, 2003 BP Equipment Presentation Andy Barden
April 4th, 2003 BP Equipment Presentation Andy Barden

Challenges in Deepwater Environment
Hydrotesting is a common requirement for all deepwater pipelines &
flexibles – here we review the unique challenge this brings subsea:
1. Large diameter line from surface vessel to deepwater PLET
needed to flood the line with filtered, treated water
2. Long duration for water temperature to stabilise if surface water
(say 25degC) used to flood line at 1000m WD (say 4degC)
3. Recovery of gauging tool to surface to verify mechanical
condition prior to pressure testing

Challenges in Deepwater Environment
Hydrotesting is a common requirement for all deepwater pipelines &
flexibles – here we review the unique challenge this brings subsea:
1. Large diameter line from surface vessel to deepwater PLET
needed to flood the line with filtered, treated water – use of RFM
eliminates the need for large diameter subsea downlines. Also
SHP allows line to go straight in to hydrotest again saving time
and reducing risk
2. Long duration for water temperature to stabilise if surface water
(say 25degC) used to flood line at 1000m WD (say 4degC) – the
RFM floods the line using ambient temperature water meaning
no stabilisation time
3. Recovery of gauging tool to surface to verify mechanical
condition prior to pressure testing – the SGT (Smart Gauge Tool)
allows results of gauging survey to be annunciated via a pinger
and can then be left in for the test saving 1 recovery run

RFM Overview

RFM Overview
• Small, compact, light 4.2m x 3.2m x 2.5 / 6,000kg
• Fully meets specifications
• Chemicals on board, introduced by venturi
• Filtration on board
• Instrumentation onboard
• Range of pipeline sizes, set to desired
flowrate/pig speed
• Additional hydro-test capability if desired
• Particularly beneficial in deepwater
• ROV friendly - ROV Engineers Involved in Design

SHP Overview
• BJ designed hydraulically driven test pump
operated by ROV
• Various flows and pressures available,
determined by available ROV power but
circa 35 litres/minute to 600 Barg
• Eliminates the need for and downline
• Can be fitted to RFM Boost Pump skid or
stand alone skid
• Saves time vs. down-line deployment
Pipeline
Nomial
bore
(inches)
Length
(metres)
Vol/bar
(litres)
Bar/min ex SHP
Test Pressure
(bar)
Vol to test
pressure
(litres)
Time to test
pressure
(hours)
TS-WI-FL-01 12 9553 31.83 0.94 431 114523 7.62
TS-P-FL-01 10 9577 21.71 1.38 431 9921 5.20
TS-P-FL-02 10 9248 20.96 1.43 431 9580 5.02
TS-T-FL-01 8 9553 13.57 2.21 431 6210 3.25
TS-GL-FL-01 8 9479 13.47 2.23 431 6162 3.23

SGT Overview
Developed using patented sensor / pressure vessel unit. Uses a
segmented urethane disc to supplement the existing aluminium
gauge plate. by recording the number of deformations beyond the
given tolerance. For deepwater pipelines this means the following:
• Smart gauge is run at flooding stage
prior to hydrotest and is received in
laydown head
• ROV / surface hydrophone picks up the
signal and immediately confirms the
success of the gauging run
• Hydrotest can then proceed without
removal of the laydown head to
inspect the gauge plate
• Fixed gauge plate is then rechecked
upon final removal of the laydown head

Subsea Data-logger Overview
• Can be connected to 4 lines
at once saving time
• Monitors pipelines during
hydrostatic test
• Records pressure and
temperature
• Allows vessels to carry out
other work
• Recovered and downloaded
when convenient
• Deployed and recovered by
ROV
• Can be linked to surface via
BJ Update™ system
Video

Subsea Operation
V

Future Developments
DEVELOPMENT
• Remote closing of valves at
discharge end of pipeline under
test
• Improved pig detection for both
launch and receive
• Real time transmission of test
data to surface using acoustic
telemetry
BENEFIT
Saves 1 vessel move and 1 ROV
deployment = $ and time saving
Removes need to “over-pump”
during any subsea pigging
operation = $ saving &
environmental benefit
Already under field trials (BJ
Update™) and soon operational –
means vessel can work elsewhere
during test = $ saving & improved
vessel utilisation

Summary & Conclusions
1. System design has a major impact on how a line can be tested and
commissioned – in the Asia Pacific Region we are seeing many using
complete subsea architecture with few permanent surface connections
2. The biggest risk in deepwater pipeline operations is making and maintaining
the connection between the vessel and subsea connection
3. The cost of any support vessel required to support subsea pre-commissioning
far outweighs the cost of the subsea pre-commissioning spread
4. Today it is possible to flood, gauge and hydrotest a deepwater pipeline
without the use of any down-line – at BJ Services alone this technique has
been successful employed on over 100 pipelines
5. As ROV size and hydraulic power increases it will be possible to run larger
pumps improving flooding and testing time
6. Combining remote valve closing, remote data transmission and guaranteed
pig location we can further reduce the risk whilst improving the efficiency of
deepwater pipeline pre-commissioning

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