BP 2010 Annual Report Download - page 37

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Businessreview
Business review
Subsea
SubseainterventionactivitieswereinitiatedbyBPimmediatelyfollowing
theexplosion.Initialattemptstostoptheowofoilfocusedonattempting
toactuatethefailedBOPwithremotelyoperatedvehicles(ROVs).Atthe
sametime,planningalsobeganfortworeliefwells.Attemptstostopthe
owofoilbyactivatingthevariouscomponentsoftheBOPcontinueduntil
5May,whileplansandtoolsforpotentialcontainmentoptionswerebeing
developedinparallel.
From5MayBPattemptedtocontaintheowofoilusinganumber
ofdifferentstrategies.Firstly,oneofthethreeleakpointswasplugged
withtheinstallationofadrillpipeovershotandpack-offdevice,reducing
thecomplexityoftheseabedsituation.Followingafailedattemptto
containtheowofoilusingacontainmentdome,ariserinserttubetool
wassuccessfullydeployedintheendoftheriseron16May.Thisallowed
roughly3,000barrelsofoilperday(b/d)tobecapturedandreturnedtothe
surfaceforprocessingonthedrillshipDiscovererEnterprise.Anattempt
wasalsomadeto‘topkill’thewellbypumpingheavydrillingmudintothe
wellathighratesbutthiseffortwasunsuccessful.Byshearingand
removingadamagedsectionofriserfromthelowermarineriserpackage
(LMRP)ontopoftheBOPstack,itwaspossibletoattachanew
containmentsystem(sometimesreferredtoasatophat).Thissystem
allowedforupto15,000b/dofoiltobeproducedthroughthisnon-sealing
LMRPcapviaarisertotheDiscovererEnterpriseforprocessing.
Containmentcapacitywaseventuallyenhancedtoover40,000b/dofoil.In
total,approximately827,000barrelsofcrudeoilwererecoveredusingthe
variouscontainmentsystems.On10July,thetop-hatcontainmentcapwas
removedfromtheLMRPtoallowtheinstallationofathree-ramcapping
stack,whichwascompletedon12July.
TheowofoilintotheGulfofMexicowasnallystoppedon
15July.Afterverifyingintegrityofthecappingstack,astatic-killprocedure
wasexecuted.Followingaseriesoftestsandthepumpingofheavydrilling
mud,staticconditionswereachievedintheMacondowellon3Augustand
cementwaspumpedintwodayslater.On2September,afterasuccessful
testofthecementplug,thecappingstackwasremovedfromthetopof
theBOP.
On3September,theBOPwasremovedfromtheMacondo
wellheadtobereplacedbytheBOPstackfromtheDevelopmentDrillerII.
TheDeepwaterHorizonBOPwassubsequentlyrecoveredtosurface,
preservedandshippedtotheNASAMichoudFacilityinLouisianafor
examinationbytheUSgovernmentandotherparties.
Progressonthetworeliefwellscontinuedinparallelwiththe
containmentoperationsoutlinedabove.Therstreliefwellwasdelayedon
severaloccasionsduetoadverseweatherandwhilecriticaltestingand
operationswereconductedontheMacondowell.On16September,the
rstreliefwellsuccessfullyintersectedtheMacondowellbore.On
19September,aftercementingoperationsonthereliefwellwere
complete,theMacondowellwasofciallydeclaredkilled.
TheP&AoftherstreliefwellwascompletedbytheDevelopment
DrillerIIIrigon30September.P&AoftheMacondowellwasconcludedon
8NovemberbytheDevelopmentDrillerII,andtheP&Aofthesecondrelief
wellisinprogressandisexpectedtocompleteinearlyMarch2011.
Worktorecoverandsecurethesubseainfrastructureusedforthe
variouscontainmentsystemscommencedfollowingcompletionofthe
MacondowellP&Aprogrammeandwascompletedon8January2011.
Duringthelatterstagesoftheresponse,workcommencedtorestoreand
decontaminatethemanyvesselsinvolvedintheincident.Thisislargely
complete,withtheremaining25vesselsexpectedtobecompletedbythe
endofApril2011.
TheonlyoutstandingworkassociatedwiththeMacondositeisthe
seabedandseismicsurveysofthearea.Inconsiderationof,andsubjectto,
theweatherconditions,itisanticipatedthattheseabedandseismic
surveyswilltakeplaceattheendofrstquarterof2011.
Shorelineandsurface
Theprioritiesfortheshorelineandsurfaceresponsewereremovingoil
fromthesurfaceoftheGulf,preventingoilfromreachingtheshorelineand
cleaningupanyoilthatdidreachtheshores.Theresponsestrategy
includedaerialsurveillancetounderstandwhereconcentrationsofoilwere
located,mechanicalskimming,controlledsurfaceburning,applicationof
dispersants,andmultiplein-waterandonshoreboomingtechniques.
Onshore,multipletechniquesforcleaningandremovingoilfrommarshes,
wetlands,andbeachesweredeployed.BPworkedwithlocalorganizations
toreneexistingareacontingencyplanstoenablethemosteffective
responsetothespill.
Extensivesurfaceskimmingactivitiestookplace,rangingfrom
large-scaleoffshoreskimmerstoinlandandshallowwaterequipment.The
UACalsoleverageditsVesselsofOpportunity(VoO)programmetoassist
withthisandtosupporttheshandwildlife,ShorelineClean-up
AssessmentTeam(SCAT),andRapidAssessmentTeam.
Controlledinsituburningofoilonthesurfaceofthewaterwas
conductedwhereconcentrationsofoilwithsuitablecharacteristicscould
beidentied.Approximately400controlledburnswereperformed,which
intotalremovedanestimated265,450barrelsofoilaccordingtotheUAC.
Chemicaldispersantsweredeployedundertheclosesupervisionof
theUAC.Dispersantsaremixturesofsolvents,surfactantsandother
additivesthatbreakupthesurfacetensionofanoilslickorsheenand
makeoilmoresolubleinwater.Onthesurface,dispersantshelpbreakoil
downintomicroscopicdropletsthatcanbedispersedthroughthe
seawaterandmoreeasilydegradedbyoil-eatingbacteria.Subsea
applicationofdispersantswasusedtobreaktheoilintosmallparticlesthat
dispersethroughoutthewatercolumn,formingamorediluteoil-and-water
solutionthatdegradesmoreeasily.
BPworkedcloselywithstateandlocalofcials,seekingtoprevent
shorelineoiling.Theeffortinvolvedsignicantdeploymentofboom.BP
workedcloselywithexpertsfromtheUSCoastGuard,theUSFish&
WildlifeService,theNationalOceanicandAtmosphericAdministration
(NOAA),theNationalParkService,aswellasstateagenciestoidentifythe
mostsensitivewildlifehabitatsandprioritizeappropriatespill
countermeasures.Thesemeasuresincludedboomingwildliferefugesand
usingmethodstodeterwildlifefromenteringoiledareas.BPalso
establishedanimaltreatmentfacilities,withsignicantcapacitytotreat
birds,mammalsandturtles.
BPAnnualReportandForm20-F2010 35