deep water seabed intervention - iploca · deep water seabed intervention jan vlak – operations...

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Deep Water Seabed InterventionJan Vlak – Operations Manager

Van Oord Offshore Offshore and EPC Contractors

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Subsea Rock Installation

Rock installation in deep and shallow water o Pre lay support for subsea pipelines, cables and

structureso Post lay support for the stabilization of subsea

pipelines and cableso Scour protection around structureso Ballasting

Equipment o Flexible Fall Pipe Vessels (FFPV)

For deep water installation up to 1500 meters o Side Stone Dumping Vessels (SSDV)

For shallow water installation to 30 meters

Offshore and EPC Contractors

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Deep water seabed intervention using excavation techniquesHow deep?Two projects: 1. Nothern Scarp Australia – 625m / 657m2. Polarled, Norway – 115m / 375m


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Northern Scarp Australia Scope of WorkPreparation of the Jansz Field pipeline route

ClientChevron Australia Pty Ltd

LocationAustralia, Gorgon/Jansz Field


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Northern Scarp Australia


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Profile of the northern scarp crossing project


8 m to be removed

-/- 657 m !!

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Northern Scarp AustraliaSoil conditionso CPT = 2.5 – 3.5 MPa.o Hard Silt o Su = 80 – 200 kPa


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Primary approach: o Flexible Fall Pipe Vessel Tertneso Equipped with FPROVo And High Pressure Jetting Device (Clay Cutter)


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Northern scarp Australia

Key elements of the Primary Approacho Pumps at deck levelo Composite coiled tubing in combination with Fall Pipe ROVo Higher accuracy of controlling excavation tools (Fall Pipe ROV)o Back up / alternative tool – Clamshell Grabo Option to install rock


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Primary approach: o Unfortunately, the “hose” failed.


And then????

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Primary approach:

o Flexible Fall Pipe Vessel Tertneso Equipped with FPROVo And High Pressure Jetting Device (Clay Cutter)

Alternative approach: o Clamshell Grab or

Deepwater Excavation System (DES)


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Northern Scarp project

Plan B – Deep Excavation System


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Northern Scarp project

Plan B – Deep Excavation System (movie)


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Project progress


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As built main trench


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Client satisfaction

“I would like to express my gratitude and admiration for the crew of the Tertnes that has done all the hard work.

It has been a bit of a difficult start, but with the grab as an add-on to the FPROV all of you have once again demonstrated the outstanding ability and agility of Van Oord and Tertnes to achieve the extraordinary.”


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Polarled Norway

Scope of WorkRemoval of high peaks on the Polarled Route by FFVP Tertnes in deep excavation mode at 115 – 375 m waterdepth

ClientStatoil

Location50 locations along the Polarled pipeline route Norway


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Polarled Norway


To be removed

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Polarled Norway

10,000 m3 of excavation saves 350,000 m3 of rock


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Polarled Norway

Soil conditionso Soft Clayo Su = 10 – 50 kPao Risk of some Hard Clay

and Cobbles/Boulders


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Polarled NorwayCorals


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Polarled Norway

Dedicated disposal area’s


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Polarled Norway


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Polarled Norway


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Polarled Norway


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Polarled Norway

Location


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DEEP EXCAVATION SYSTEM (DES)

Conclusions o Two projects have been very successfully executedo Two very happy clientso Combination of Grab with FPROV gives good positioning controlo Good control of deposited materialo Grab Excavation System gives very limited turbidity (Coral)o Van Oord has a patent on Deep Excavation System.


deep water seabed intervention - iploca · deep water seabed intervention jan vlak – operations...

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