Scour Protection Field Operations

8/18/2019 Scour Protection Field Operations

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Scour Protection Project

Field Operations

1st Phase 2nd Phase 3rd Phase


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1st Phase Pre-Installation Survey

• A survey line is run along the centre design

position of Monopile

•The DTM (Digital Terrain Model) of Presurvey is processed

•According with weather conditions a grid isdefined for rock dump operations


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2nd Phase Rock Installation

• Operations commence with rock installation rockalong the central line of the grid according with project

specs (~23m ø)

• he !essel is relocated " m awa# form central line androck is installed along that second line

• Rock installation contin$es e!er# "m spacing to co!erone half of the area speci%ed

• &$'se$entl# the second half is co!ered with the

same proced$re and spaces 'etween lines are %lled into '$ild $p the sco$r protection

• *$ring operations additional s$r!e#s are cond$ctedto !erif# the geometr# of sco$r protection $nderinstallation

• +ased on s$r!e# res$lts areas to 'e %ll in are

programmed to reach the %lter la#er specs


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,actors to take in co$ntfor &co$r Protection

Installation

• Water Depth. Shallow Watersafecting manoeuvrability o ROV

• Diameter o rock !" # $"% vs.

Vertical tolerance & to &.'m &" to()*"%

• Subsea currents

• Weather +on,itions Win,- Swellan, current%

• bove actors an, their combinationhave in/uence on the Subsea Rock0nstallation SR0%


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3rd Phase Post Installation&$r!e#

• s result o 1ost20nstallation Survey- the ,iferencean, pro3les chart generate,- allows to ,e3ne i

installe, rock ul3l the scour protection specs• Diferential colour chart contours is generate, by,epth ,iference between 1ost2survey pro3le an,minimum high re4uire, mo,el% or the scourprotection

• 5he mo,el is ,e3ne, by the 1re20nstallation Survey,epth results plus minimum high or the scour

protection

• scale o colour co,es elevations every &.)m or aeasy i,enti3cation o those areas out o speci3cation

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Post-Installation Pro%le

• +oloure, areas outsi,e the9!m : circle area calculate,base, in slope o mo,el.


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.ertical *at$m

• /ccording with OI0 anne 14 5he preferred !ertical dat$m for$se o6shore is 7owest /stronomical ide (7/)8

• 7/ 9ater 7e!el *at$m is 'ased on the lowest predicted tideepected to occ$r in a 1 #ear period calc$lated thro$gh theharmonic anal#sis of data collected d$ring a speci%c time

•7/ *at$m (:*) is completel# distinct from the 0eodetic *at$m(elipsoid) (90&;< or *==>2 ?O@cial .ertical Reference stem in0erman#-)

•o de%ne the relationship 'etween 7/ *at$m and 0eodetic *at$min a speci%c area it8s re$ired to esta'lish relationships 'etweendi6erent tidal stations referred to the 0eodetic *at$m

• / method to ha!e a proper !ertical control is the :o-idal charts ora RA 0P& correlated with a tide ga$ge at the speci%c site

• ,or p$rposes of this stage of the project !ertical control co$ld 'ecorrelated 'etween s$r!e# res$lts against 7/ *ata pro!ided '#&O9


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=ow *epths arecorrelatedB

• *O9 pro!ided 7/'ath#metric information foreach location

• Pre-Installations 'ath#metricres$lts are compared with*O9 data

• *ata from s$r!e# are not tidecorrected and a di6erence indepth is o'ser!ed

• +ath#metric data form Pre-s$r!e# are shifted to matchwith *O9 data

• aking as reference the shifted

data Pre C Post s$r!e#s arecompared to de%ne the

*O9 7/ *epth

Pre-s$r!e#*epth

*O9 *epth D Pre-s$r!e# *epth


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,I>/7 RE&F7&

• 1re20nstallations Survey +ontours

• 1ost20nstallation Survey +ontours

• Diferential D56 between 1ost2Surveyan, 6o,el

• +ross 1ro3les


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AS- BUILT

CHART


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References4• 9ilfried E77GER C Patrick 0O,,I>E 5idal :orrection Fsing 0P& - *eterminationof the :hart *at$m8 G$nich 0erman# Octo'er ;-13 2HH cons$lted on*ecem'er ;th 2H12 at

http4JJwww%gnetJp$'J%g2HHJpapersJtsHJtsHKH2KellmerKgo@netKH3

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Scour Protection Field Operations