InternationalAssociationofol&Gas

producers

ipieca

REPORT

594

SEPTEMBER2025

SourceControlEmergencyResponsePlanningGuideforSubseaWells

I4

SourceControlEmergencyResponsePlanningGuideforSubseaWells

Contents

Scope

7

Foreword

8

Part1:OverviewofSourceControlEmergencyResponse

11

1.1SourcecontrolIncidentManagementTeamstructure

11

1.1.1ReliefWellGroup

13

1.1.2SimultaneousOperationsGroup

13

1.1.3WellCappingGroup

13

1.1.4EngineeringServicesGroup

14

1.1.5SubseaSurveyTaskGroup

14

1.1.6BlowoutPreventerInterventionTaskGroup

14

1.1.7DebrisClearanceTaskGroup

14

1.1.8SubseaDispersantTaskGroup

15

1.1.9CappingOperationsTaskGroup

15

1.1.10WellContainment(Flowback)Group

15

1.1.11OffsetInstallation(Non-VerticalAccess)TaskGroup

15

1.2Sourcecontrolkeyevents

16

1.3EmergencyResponsePreparedness

16

1.4Responseplanimplementation

18

Part2:EngineeringActivitiestoSupportSCERPPlanning19

2.1Summaryoftasks19

2.2WorstCaseDischarge22

2.3CasingdesignforWorstCaseDischargeanddisplacementtohydrocarbon(blowoutloadcase)22

2.4Wellintegrityandsourcecontrolselection22

2.5ConsiderationsonBlowoutPreventerintervention23

2.6Structuralintegrity23

2.7Plumeevaluation24

2.8ComputationalFluidDynamics/upliftforces25

2.9Locationspecificconsiderations25

2.10Dispersantuseandapproval26

2.10.1Regulatoryapproval26

2.10.2Quantitiesandreplenishment27

2.10.3Watercolumnmonitoring27

2.10.4Dispersantdelivery28

2.11Cappingconsiderations29

2.12Reliefwellplanningandinterfacingwithsourcecontrol29

2.13Mutualaid29

SourceControlEmergencyResponsePlanningGuideforSubseaWells

I5

Part3:CappingStackPlanningandInstallation

3.1Cappingconsiderations

3.1.1General

3.1.2Cappingselection

3.1.3Mobilizationoptionsandpre-deploymenthandling

3.1.4RemotelyOperatedVehiclesinterfacepoints

3.1.5Cappingstackactuation

3.1.6Alternativeinstallationmethods

3.1.7Connectioninterfacepointsandclashchecks

3.1.8Handlingtoolsandmethods

3.1.9Considerationsfortransitioningfromcaptocapandcontain

3.2Cappingstackoptions

3.3Toolingandspares

3.4Landinganalysisandlandingplan

3.4.1Non-verticalaccessplan

3.4.2Inclinedwellhead

30

31

31

31

31

32

32

32

32

33

33

33

34

34

34

34

Part4:LogisticsPlanning36

4.1Logisticssurvey38

4.2Airfieldlocation38

4.3Groundtransportation39

4.4Customsclearanceformobilizationofoilspillresponseequipment39

4.5Quaysidecapabilities39

4.6Cranes,lifting,andrigging39

4.7Bulkreplenishmentandtransfer39

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Appendix1:ContainmentPlanning

40

A1.1Wellcontainmentoverview

40

A1.2Capandcontainmentplanningprocess

44

A1.3Wellcontainmentsystemmodellingandanalysis

45

A1.4Fieldlayoutdefinition

46

A1.4.1Keyoperationaltasksforsystemdeployment

47

Appendix2:SCERPGroupDescriptors

49

A2.1Subseasitesurveyandinitialassessment

49

A2.2BlowoutPreventerintervention

50

A2.3Debrisclearance

51

A2.4Subseadispersantapplication

52

A2.5Capping

54

A2.6Capture,contain,andflowtosurface

56

A2.7SimultaneousOperationsplanning

57

A2.8Decontaminationanddemobilization

58

Appendix3:2025GlobalCappingStackResourceLocations

59

Appendix4:AnOverviewoftheCappingStackInstallationProcess

63

Appendix5:Examplesof2Dand3DEngineeringDrawings

64

Appendix6:CappingandContainmentPlanChecklist

70

Glossary

74

Acronyms

75

References76

I7

Scope

ThisreporthasbeendevelopedtoguideoperatingCompaniesintheplanningandpreparationofaneffectivesubseasourcecontrolemergencyresponseplan.

Thescopecoversbasicemergencyresponseorganizationalformat,rolesandresponsibilities,

welldesignconsiderations,sourcecontrolresponseoptionsandrecommendationstoconsiderforimplementation.ThisdocumentintendstoassistoperatingCompaniesinthedevelopmentoftheiremergencyresponseplansandprovidenon-technicalstakeholdersaninsightintowhatisinvolvedinasubseasourcecontrolresponse.

Topicsaddressedinthisdocumentinclude:

?Overviewofasubseawellsourcecontrolresponse.

?Elementsofasourcecontrolresponse.

?Emergencyresponseframework.

?Welldesignconsiderationsforsupportingsourcecontrolequipment.

?Subseawellsourcecontrolresponseplanning.

?Cappingstackequipmentandpreparation.

?Flowcontainmentequipmentoptionsandpreparation.

Topicsthatarerelatedtoaspectsofsourcecontrolandmaybementionedthroughoutthisdocumentbutdonotformpartofthisdocument’scorebodyinclude:

?Preventionofwellcontrolincidents.

?Surfaceoilspillresponse.

?Surfaceordrytreewellresponse.

?IncidentCommandSystems(ICS)indetailorformalICSstructures.

?Continualtrackingofcappingstacksystems.

?Regulatorycompliance.

?Reliefwellplanning,drilling,andincidentwellkilloperations.

I8

Foreword

Itisnotpossibletoeliminateallrisksofablowout,butwherepossible,subseawellscanbedesignedtosurviveawellblowout,becapped,andeitherrestrictormitigatethedischargeofhydrocarbonstotheenvironment.

WhiletheIOGPWellsExpertCommittee(WEC)believesthatthefocusoftheindustryshould

primarilybeonpreventingblowouts,theyacknowledgethattheoilandgasindustrymustalsobepreparedtoadequatelyandefficientlyrespondtoamajorlossofcontainmentfromasubseawellsystematicallyandwithastandardmethodology.

WellSourceControlisagenerictermforallactivitiesrelatedtothedirectinterventionofawellthathasexperiencedlossofcontainmentwiththeintenttohaltorcontrolthereleaseofhydrocarbonstotheenvironment.

Wellsourcecontrolresponseoperationshavebeenaroundforsometimeandinthehistorical

contextofsubseaoperations,theprimarymethodtoestablishwellcontrolwasbydrillingareliefwell.Reliefwelloperationsareaneffectivebutatime-consumingmethodandcanhavesignificantenvironmentalconsequences.Historically,subsearemedialsourcecontrolresponseoptions

werelimitedduetolackofspecializedequipmenttailoredforthedemandingenvironment.Theevolutionofsubseacappingstacktechnologyandassociatedcontainmentequipmenttechnologydevelopmentshasenabledchangesandprovidedadditionaloptionstoaddresssuchevents.

Theabilityofthecappingstacktoisolateandstopflowinarelativelyshortperiodoftimewasakeyimprovementinsourcecontrolresponsecapability.Incertaincircumstances,itmaynotbepossibletosafelyshutinawellwithacappingstack.Inthiscase,containmentmethodsmaybechosen

whichmaylimittheenvironmentalimpactswhileareliefwellisbeingdrilled.

Asdeepwaterwellshavegrownincomplexityandarebeingdrilledfurtherbelowthemudlineinto

higherflowpotentialreservoirs,theindustryhasrecognizedthathavingappropriatesubseasourcecontrolequipmentavailableandhavingvalidresponseplansinplacetorapidlyinterveneandshutinanincidentwellareparamounttominimizeenvironmentalimpacts.Aspartofthatlearning,IOGP’sGIRGreport,IOGPReport463-Deepwaterwells-GlobalIndustryResponseGrouprecommendations

waspublishedamongothers,whichrecommendedthatoperatingCompanieshaveaSourceControlEmergencyResponsePlan(SCERP).1TheSCERPcontainsinformationonmanagementsystems

andresponseplans.Managementsystemsaretypically,organizationalstructures,keydocuments,readypreparedAuthorizationsforExpenditure(AFEs),andcommunicationprotocols.Plansare

theactivitiesthatmustbeperformedtosomedegreeineverysubseasourcecontrolincidentandareneededtoensurethatcertainequipmentrequirementsaremet,proceduresaredefinedandunderstood,andrequisiteresponsepersonnelaretrainedandavailable.

1Note:TheGIRGreportswillnotberevisedbecausetheywereproducedasrecommendationsandareintendedtoremainunchanged.

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SourcecontrolmethodsincludeBlowoutPreventer(BOP)activationthroughsecondarycontrol

systems,capping,andcontainmentandreliefwelldrilling.BOPactivationinvolvestryingtoclose

theBOPusingaRemotelyOperatedUnderwaterVehicle(ROV)andassistanceofsubseapumpingsystems(e.g.,interventionskid,enhancedROVpumping,etc.).Subseacappinginvolvesinstalling

acappingstackontotheincidentwellandthenclosingittoshutoffflow.Subseacontainment

involvesinstallingsubseaproductionequipmenttodivertflowinghydrocarbonsbacktosurface

forsurfacecapturethroughoneofseveralmeansthatarebeyondthescopeofthisdocument.

Containmentmaybeaninterimphaseortacticalresponsewhenwellintegrityconcernsprohibit

thesafeshutinofaflowingwell.2Forallintentsandpurposes,thecappingstackportionofboth

conceptsisthesame.Toavoidconfusion,reliefwellactivitiesshouldbeunderwayinparallelto

cappingactivities.Reliefwellplanningisbeyondthescopeofthisdocument.(Formoreinformationonreliefwellplanning,IOGPReport598Reliefwellplanningforsubseaapplications).

WellCappingandWellContainmentarecomplex,cross-functionalactivitieswithsignificant

logisticsandSimultaneousOperations(SIMOPS)considerations.Theactivitiesrequirethe

deploymentofequipmentnotnormallyundercontracttotheoperatorandrequiresspecificdetailedplans,investments,contracts,andmutualaidagreementsnotspecificallyrelatedtonormaldrillingandcompletionoperations.Furthermore,operatorinvestmentoftimeandresourcesforplanning,preparedness,andthedevelopmentofresponseorganizationalcapabilityisnecessarytoeffectivelyintegratetheoperatorsresponseequipmentandincidentresponsecapabilities.Overall,the

operatingcompanyneedstoowntheplanandensureallassumedinterfacepointsarerobust.

Subseacappingequipmentisavailableindustry-widethroughmembership,subscription,ordirectpurchasefrommanufacturers.Containmentsystemsareconsiderablymorecomplexandrequireextensiveadditionalresourcestodeveloparobustresponseplan.

TheobjectiveofthisdocumentistopromoteastandardapproachintheplanningandimplementationofaSCERP,providepracticalguidance,anddescribewhatneedstobeconsideredaswellasits

relevance.

Mostofthisdocumentfocusesoncapping,asthistypicallywillbethemosteffectiveresponseandtoavoidconfusion,contentthatrelatestocontainmentislocatedinAppendix1.

2Note:WithinthecontextofSourceControl,therearesomedifferencesinlanguageusedintheU.S.andinternationally.SomeexamplesoflanguagedifferencesincludetheU.S.termCapandContain,whichinternationallymeansCapping,andCapandFlowwhich

internationallymeansContainment.Thisdocumentfollowsinternationallanguageconventions.

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UnderstandingCappingandContainmentResponses

Thelevelofsourcecontrolemergencypreparednessshouldbeatechnical,risk-baseddecision.It

shouldconsiderwellfactors,industryandlocalcapability,andregulatoryrequirements.Ifawellcanbecappedandsafelycontainreservoirfluids,cappingshouldbetheprimaryresponse.However,

cappingisscenariospecificandactualincidentevents,seabedequipmentconditions,andwellborecharacteristicsmaypreventacappingstackfrombeinginstalled.

Cappingpreparednessrequiresaccesstoacappingstackandaplanningprocesstoverifycappingfeasibility.Operatorownedequipmentmaybeneededfortherelatedcappingactivities.Muchofthisworkissimilartoblowoutcontingencyplanning,butwiththeneedforspecialequipment(especiallyifverticalaccesstothewellischallenging).

Whenevaluatingwhethertoprepareforcappingorcappingpluscontainment,animportantfactortoconsideristhattheseactivitiesmaybelimitedbythesurfacepressurecontrolequipmentor

downholewellintegrityandcouldrequiresignificanttimefordeploymentandcommissioning(ifapplicable).Thetimeandcomplexityinvolvedwithinstallingandcommissioningacontainmentsystemshouldbeevaluatedrelativetothetimerequiredtodrillareliefwell.

Containmentisaresponseoptionthatfollowsfromcappingandis,essentially,theconstructing

andcommissioningofaminisubseaproductionandoffloadingsystem.Preparednessrequires

specialistexpertise,comprehensiveengineeringactivities,andaccesstoequipmentthroughserviceagreementsorprocurement.Containmentequipmentincludessubseainfrastructureandcontrol

components,productionrisers,surfaceproductionvessels,andoffloading/disposalsystems.A

notableconsiderationfactoristhatsomeequipmentsuchassuitablydesignedmobileorfloatingtemporaryproductionsystemsarenotreadilyavailableinallpartsoftheworld.

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Part1:OverviewofSourceControlEmergencyResponse

ThedevelopmentofarobustSourceControlEmergencyResponsePlan(SCERP)willbespecifictoeachcompany’sIncidentManagementSystem.Whetherdirectlyorindirectly,manyoperatingcompaniesandgovernmentsfollowtheprinciplesoftheIncident

CommandSystem(ICS)asdefinedbytheUSNationalIncidentManagementSystem

(NIMS).ICSprovidesastandardizedprocessformanagingemergencyresponsesof

varyingdegreesofcomplexity.Tohelpcommunicateclearlyinthisdocument,asimilarorganizationalstructureresponseisadopted.

Thefigurebelowdisplaysthefirstlevelframeworkfortheincidentcommandsystem.AsformallydefinedbytheICSsystem,sourcecontrolwouldresidewithintheoperations

section.However,duetothecriticalityofsourcecontrolduringablowoutresponse,someoperatorsandresponsenetworksplacesourcecontrolasadirectreporttoincident

command.

Figure1-Firstlevelframeworkforanincidentcommandsystemmodel.

1.1SourcecontrolIncidentManagementTeamstructure

TheSourceControlIncidentManagementTeam(IMT)structureismodularandwillbe

specifictoeachoperatingcompanyorresponsenetwork,andtothenatureoftheevent

requiringaresponse.Theunderlyingpremiseisthatthereare5mainareasoffocus:reliefwellplanning,SimultaneousOperations(SIMOPS),wellcapping,wellcontainment,and

engineering.Thesefivefocusareascanbeorganizedintogroups,withinwhichspecifictasksareidentifiedandstructuredintotaskgroups.

Differingphasesoftheresponsewillneeddifferentresourcinginthegroups,andnot

allpositionsneedtobefilledduringallstagesoftheresponse.Inaddition,individual

resourcesmaycovermultiplepositionsatdifferentstagesoftheresponse.Theincident

ownercanalsosupplementtheorganizationwithvendor,thirdparty,contractor,and

mutualaidresources.IOGPReport591-GuidanceforSubseaSourceControlCompetency

andSkills,offersanideaofthecompetenciesthatareoftenrecommendedtofillroles

withinthesourcecontrolorganization.AnexamplemodelforafullsourcecontrolbranchisshowninFigure2.Thereisno“definedstructure”,andthedesignvariesfromoperatorto

operatorandpotentiallyregulatoryframework.WhatisessentialisthattheSCERPdetailsastructurethatadequatelyaddressesthepotentialneedsofasourcecontrolresponse.

SourceControlEmergencyResponsePlanningGuideforSubseaWells

12

Additionalsourcecontroltasksthatshouldbeconsideredare:

?Subseasitesurvey:Inspectionandmappingoftheareaaroundtheincidentwell.

?BOPintervention:ThetaskofstoppingorattemptingtostoptheflowusingtheexistingBOP.

?Debrisclearance:ProvidingaccesstotheBOPcappingstackattachmentpoint,ifobstructed.

?Subseadispersant:Deliveringdispersanttotheflowpathtoreducetheamountof

volatilehydrocarbonsandrestoreworkingconditionsoverthewelltotheresponders.

?Capping:Mobilizingandinstallingthecappingstack.

?Offsetinstallation:Non-verticalaccessoftheincidentwellmayrequireanoffsetinstallationstrategy.

Legend

RelatedtoCapping,ReliefWellandWellKill

RelatedtoOffsetInstallationandContainmentActivities

SourceControlBranchDirector

DeputySourceControlBranchDirector

SIMOPSSupervisor

WellControlLeader(Contractor

ReliefWellGroupSupervisor

WellConstructionUnitLeader

WellInterceptionUnitLeader

CappingGroupSupervisor

EngineeringGroupSupervisor

GeosciencesUnitLeader

DrillingEngineeringUnitLeader

WellInterventionGroupSupervisor

WellInterceptionUnitLeader

OperationsUnitLeader

ContainmentGroupSupervisor

SubseaSurveyUnitLeader

BOPInterventionUnitLeader

SubseaDispersantUnitLeader

DebrisClearanceUnitLeader

CappingOperationsUnitLeader

OffsetInstallationUnitLeader

SubseaLayoutUnitLeader

SubseaFoundationsUnitLeader

ROV

UnitLeader

WellKill

UnitLeader

HydrateInhibitionUnitLeader

RigOperationsUnitLeader

FlowAssuranceUnitLeader

SubseaFlowlinesUnitLeader

Marine

UnitLeader

RiserSystemUnitLeader

CaptureVesselUnitLeader

ContainmentOps.

UnitLeader

Figure2-Aconceptualorganizationalmodelforasourcecontrolresponsebranch.Dependingontheoperatingcompanies’overallIMTstructure,thismodelmaytakesomedifferentformsthoughtheunderlyingtaskgroupsshouldnotchangemuch.Ifwellcontainment(flowback)wererequired,thatgroupwouldformaseparatetreeasshowntotheright.Containment(flowback)groupshouldnotberequiredforacappingonlyresponse.

SourceControlEmergencyResponsePlanningGuideforSubseaWells

13

1.1.1ReliefWellGroup

TheReliefWellGroupisresponsibleforthemanagementandcoordinationofreliefwell

designandoperations.TheReliefWellGroupcoordinatesthedevelopmentofthedrillingplansandprocedures,securesresources,andmanagesreliefwelloperationstoensure

thereliefwellsuccessfullyinterceptsitstarget.Reliefwelloperationsbeginearlyinthe

sourcecontrolprocessandcontinueconcurrentlywithallothersourcecontrolefforts

untiltheincidentwellisinterceptedandpermanentlykilled.Thisgroupwritesproceduresthatinvolvetheuseofdrillingequipmentandoffshorerigsandplansaninterceptwiththesourcewellusingintercepttechniquesandrelatedequipment.Reliefwellproceduresandplansshouldbeapprovedaccordingtoregulatoryagencyrequirementsandcoordinated

throughtheSIMOPSgroup.

1.1.2SimultaneousOperationsGroup

TheSimultaneousOperations(SIMOPS)Groupprimaryresponsibilityistocoordinate

multiplehigh-riskoperationsinvolvingvesseltrafficsuchasROVoperations,subsea

dispersantinjection,debrisremoval,wellcapping,containmentoperations,andreliefwelldrilling.TheSIMOPSGroupworksunderthedirectionofthesourcecontrolbranchdirectorandcollaboratescloselywiththereliefwellandcontainmentteams,subseaoperations,

flowengineering,environmentalunit,andlogistics.

TheSIMOPSGroupworkscloselywiththeLogisticsGroupandcoordinatesthemultiple

marineandlogisticsactivitiesassociatedwithasourcecontrolresponse.Numeroussupplyvessels,MobileOffshoreDrillingUnits(MODUs),andROVsworksimultaneouslyduring

aresponse,anditistheprimaryfunctionoftheSIMOPSGrouptoensuretheseactivitiescanoccurconcurrentlywithoutoperationalconflictorsafetycompromisebymaintainingexclusionzonesandsituationalawareness.TheSIMOPSGroupissuesandregularly

updatestheSIMOPSplanandcoordinatescommunicationsaroundit.TheyalsomaintainalignmentwiththeIncidentActionPlanandsupportreal-timedecision-makingtoensuresafe,efficient,andsynchronizedexecutionofsourcecontrolstrategies.

Dependingonthenatureoftheincidentandcompanyresponseplans,theSIMOPSGroupmayalsoassumeresponsibilitiesforcoordinatingsurfaceoilspillresponseorothertasks.Inthiscase,SIMOPSmaybecomeasubgrouptoabroaderSIMOPSfunction.Forthe

purposesofthisdocument,theunderlyingpointisthattheyarethelinktoco-ordinatethein-fieldresponseactivities.

1.1.3WellCappingGroup

ThefunctionoftheCappingGroupistofacilitatethetesting,installation,andmonitoringofacappingdeviceandtocontrolorstoptheflowofhydrocarbonsintotheenvironment.TheCappingGroupsourcesanddirectsthedeploymentofallnecessaryequipment(e.g.,connectiondevices,debrisclearanceequipment,flex-jointalignmentandrestrainttools,cappingequipment,valves)tofacilitatewellcapping.Inaddition,theCappingGroupis

responsiblefordevelopingincidentspecificproceduresforalloperationalstepsleadingtosafewellcapping.

14

Toachievethisinpractice,itissuggestedtobreakdowntasks,knownasmissions,into

smallersubgroupsasshownintheorganizationaldiagram,inFigure2,andexpandedoninthefollowingsubheadings.

1.1.4EngineeringServicesGroup

TheEngineeringServicesGroupprovidesarangeoftechnical,engineering,andscientificservicestotheotherresponsegroupsrelatedtotheengineeringissuesassociated

withsourcecontrol,wellintegrity,andreservoir.Someoftheservicesprovidedbythe

EngineeringServicesGroupareincludedbelow.TheEngineeringServicesGroupmayhaveexpertisethatareembeddedinothergroups.Thisincludes:

?EngineeringAssurance(e.g.,designreviewssourcedmainlybysegmentengineeringtechnicalauthorities,localtechnicalauthorities,orseniorspecialist/discipline

engineers).Assessesthestatusofvariouswellborebarrierelementsontheincidentwell.

?Re-validationofplumeorothermodelsthatmayaffectsourcecontrolactivities.

?Safety(e.g.,HazardIdentification(HAZID)orHazardandOperability[HAZOP]facilitationandactiontracking).

?Liaisonwiththirdpartysciencegroups.

?Organizationalcapabilityandresourcing(e.g.,assistothergroupsinfindingrequiredengineering/specialistresources,e.g.,porepressureprediction).

?Specializedgraphicartsandtechnicalwritingskills(e.g.,toassistwithdevelopingpresentationsandstoryboardsforSIMOPSandengineeringplans).

1.1.5SubseaSurveyTaskGroup

TheSurveyTaskGroupisresponsibleforthemanagementandcoordinationofsurveyingthesitesubsea.Theteamhelpsgatherdataforallothersourcecontroleffortstoassistinthedevelopmentoftheoperationalplansandprocedures.ThisgroupconductsoperationsutilizingsurfacevesselsandROVs.

1.1.6BlowoutPreventerInterventionTaskGroup

TheBlowoutPreventer(BOP)InterventionTaskGroupisresponsibleforthemanagementandcoordinationofaninterventionontheBOPoftheincidentwell.ThisTaskGroupmay

alsoberesponsibleformethanolinjectiontopreventorremediatehydrateformation

duringoperations.Basedontheinitialsubseasurveyresults,thetaskgroupassessesthesituationanddevelopstheBOPinterventionplansandprocedures,securesresources,andmanagesBOPinterventionoperationswiththeobjectiveofclosingtheBOP.IftheexistingBOPcanbesuccessfullyclosedtosealthewell,thefocuscanshifttowellkilloperations.

1.1.7DebrisClearanceTaskGroup

TheDebrisCleara