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

SUBSEA ASIA 11 th June 2008

Advances in Subsea and Deepwater Pipeline Pre-commissioning

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