Revised Outer Continental Shelf Lease Exploration Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. May 2011 

## Appendix K

Ice Management PlanRevised Outer Continental Shelf Lease Exploration Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. May 2011 

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### Shell Gulf of Mexico Inc. 3601 C Street, Suite 1000 Anchorage, AK 99503



## ICE MANAGEMENT PLAN
Chukchi Sea

Submitted to:

U. S. Department of the Interior Bureau of Ocean Energy Management, Regulation and
Enforcement
Alaska OCS Re g ion

Submitted by:
Shell Gulf of Mexico Inc.

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. i May 2011 

## Table of Contents

I. INTRODUCTION .................................................................................................................. ....................... 1

II. DEFINITIONS ................................................................................................................... ........................... 2

A. R OLES AND R ESPONSIBILITIES ........................................................................................................... 2

B. D EFINITIONS AND A BBREVIATIONS ................................................................................................... 2

III. VESSELS COVERED BY IMP ........................................................................................................ ........... 4

IV. SHELL ICE AND WEATHER ADVISORY CENTER ............................................................................ 6

V. ICE ALERT LEVELS AND PROCEDURES ............................................................................................ 8

VI. ICE MANAGEMENT PHILOSOPHY ..................................................................................................... 11

VII. WELL SUSPENSION PROCEDURES. ................................................................................................... 13

A. W ELL S USPENSION O PTIONS ........................................................................................................... 13

VIII. MOORING SYSTEM RELEASE/ RECOVERY .................................................................................... 15

A. C ONDITIONS P RESENT TO I NITIATE M OORING S YSTEM R ELEASE AND R ECOVERY .......................... 15

B. R ELEASE O PTIONS ........................................................................................................................... 15

IX. MOVING ONTO OR RETURNING TO THE DRILL SITE ................................................................. 15

X. TRAINING ...................................................................................................................... ............................ 16

XI. ATTACHMENTS ................................................................................................................... .................... 17

A TTACHMENT 1

– E XTRACT FROM C RITICAL O PERATIONS C URTAILMENT P LAN .......................................... 19
A TTACHMENT 2

- V ESSEL D ESCRIPTIONS ..................................................................................................... 21
A TTACHMENT 3

– S HELL I CE AND W EATHER A DVISORY C ENTER ................................................................. 29
A TTACHMENT 4

– W ELL SUSPENSION O PTIONS AND C ONTINGENCIES ........................................................... 31

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### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 1 May 2011 I. INTRODUCTION

SCOPE

A Critical Operations and Curtailment Plan (COCP) will be in place for the Shell Gulf of Mexico Inc. (Shell) Chukchi Sea Exploration Drilling Pr ogram. As part of the COCP, this Ice Management Plan (IMP) has been developed. The description of notification of curtailment (an excerpt from the COCP) is presented in Attachment 1.

The IMP addresses the following activities:

• Vessels

• Shell Ice and Weather Advisory Center (SIWAC)

• Ice Alerts and Procedures

• Ice Management Philosophy

• Well Suspension Procedures

• Mooring System Recovery and Release

• Moving onto the Drill Site

• Training

The IMP:

• Defines Roles and Responsibilities

• Establishes Alert Levels; and

• Establishes Responses to Alert Levels.

The IMP facilitates appropria te decision-making and responses to the threat of hazardous ice and procedures set forth in the IMP prevent damage or harm to personnel, assets, or the environment.

Nothing in this document takes away the auth ority and accountability of the Master(s) of the vessels for the safety of their personnel and ve ssels and for protection of the environment.

This plan is not a substitute for good judgment.

Guidance Note: This document is not intended to contain detailed pro cedures. Detailed procedures are contained within the vessel-specific operating manuals.

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 2 May 2011 II. DEFINITIONS

A. Roles and Responsibilities

Responsibilities have been defined for key personnel in section V. In addition to the defined personnel, the following positions have a role in IMP,

Chief Officer /Second
Officer/Third Officer In addition to regular duties will assist the Ice Advisor (IA)

Shell Drilling Superintendent Shell’s Drilling Superintendent is the senior Shell shore-based manager responsible for all Shell well operations offshore Alaska. Noble Drilling Superintendent The senior shore-ba sed manager (Alaska). Liaising with the Shell Drilling Superintendent.



### B. Definitions and Abbreviations

AHTS Anchor Handling Tug Supply
API American Petroleum Institute
BOEMRE Bureau of Ocean Energy Mana gement, Regulation and Enforcement
BOP blowout preventer CFR Code of Federal Regulations
COCP Critical Operations and Curtailment Plan cm centimeter(s)

Discoverer Turret-moored Drillship Motor Vessel (M/V) Noble Discoverer

DNV Det Norske Veritas

Fennica
ft M/V Fennica
foot/feet

FTP file transfer protocol

FY First-year ice. Sea ice of not more than one winter’s growth, developing from young ice; 12 inches (in.) (30 centimeters [cm]) or greater. It may be subdivided into thin FY – sometimes referred to as white ice, medium FY and thick FY.
GFS Global Forecast System
GIS Geographic Information System
Hazardous Ice Ice, which due to its size, stage of development, concentration, set and drift is considered to be a threat to the safety of personnel, the drilling vessel and well operations. Close proximity of an ice feature regardless of its set and drift may be determined to be
hazardous ice. Guidance Note: Sea state as well as visibility may influence what is categorized as hazardous ice. HOS hang-off sub

HT Hazard Time. The estimated time it will take for hazardous ice to
reach the drill site.
IA Ice Advisor
IMO International Maritime Organization

IMP Ice Management Plan

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 3 May 2011 IMV Ice management vessel. Any ice class vessel tasked with ice management duties in support of the drilling vessel. This includes the primary ice management vessel (IMV) and the ice class Anchor Handling Tug Supply (AHTS) in. inch(es)
Kulluk conical drilling unit Kulluk

LMRP Lower Marine Riser Package m meter(s)
MODU Mobile Offshore Drilling Unit

MT Move-off Time. The time required to clear decks on the anchor handler recover all anchors conventionally and move off the drill site in an orderly fashion.
M/V Motor Vessel

MY Multi-year ice. OI which has survived at least two summers’ melt.
Hummocks are smoother than on SY and the ice is almost salt-free. Where bare, this ice is usually blue in color. The melt pattern consists of large interconnecting, irregular puddles and a well developed drainage system.
NOAA National Oceanic and Atmospheric Administration
OI Old ice. Sea ice which has survived at least one summer’s melt. Topographic features generally are smoother than FY. It may be subdivided into SY and multiyear ice.
OSR Oil Spill Response
OSV Offshore Supply Vessel
PIC Person in Charge
RP Recommended Practice

SAR Synthetic Aperture Radar

Shell Shell Gulf of Mexico Inc.
SIWAC Shell Ice and Weather Advisory Center located in Anchorage. The center develops forecasts from various sources, and disseminates

same. Support Vessels Includes all vessels defined in this plan (IMV/OSR/AHTS/OSV).
SY Second-year ice. OI which has survived only one summer’s melt. Thicker than FY, it stands higher out of the water. In contrast to MY, summer melting produces a regular pattern of numerous small puddles. Bare patches and puddles are usually greenish-blue.
ST Secure Time. The time required to secure the well, disconnect the Lower Marine Riser Package (LMRP) from the blowout preventer (BOP), recover and secure the riser.
TD total depth
T-Time Total Time. The sum of ST + MT. Tor Viking
U.S. M/V Tor Viking
United States
USCG United States Coast Guard

VMT Vessel Management Team. This team is headed by the Vessel Master and includes the Shell Drilling Foreman, Noble Drilling Superintendent, Drilling Vessel IA and the Chief Engineer.

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 4 May 2011 III. VESSELS COVERED BY IMP

• Drillship - Motor Vessel (M/V) Noble Discoverer (Discoverer)

• Primary Ice Management Vessel (IMV) - the M/V Fennica (or similar)

• Secondary Ice Management Vessel and Anchor Handler – the M/V Tor Viking (or similar) –

Drillship Discoverer

The Discoverer is a true, self-contained drillship. St ation keeping is accomplished using the turret-moored, 8-point anchor system. The unde rwater fairleads prevent ice fouling of the anchor lines. Turret mooring allows orientation of vessel’s bow into the prevailing ice drift direction to present minimum hull exposure to dr ifting ice. The vessel is rotated around the turret by hydraulic jacks. Rotation can be augmented by the use of the fitted bow and stern
thrusters.

The hull has been strengthened for ice resist ance. Ice-strengthened sponsons have been retrofitted to the ship’s hull.

The Discoverer is classed by Det Norske Veritas (DNV) as a Mobile Offshore Drilling Unit (MODU) for worldwide service. It is a “1A1 Ship-Shaped Drilling Unit l” and is capable of performing drilling operations offshore Alaska. The Discoverer has been issued with a DNV Appendix to Class stating:

“ the structural strength and material qua lity of the ‘Ice Belt’ formed by the sponsons below the 8950mm A/B level, have been reviewed against the requirements for the DNV ICE-05 Additional Class Notation and found to meet those requirements (as contained in DNV Rules for Classification of Ships, Pt 5 Ch 1, July 2006) for a design temperature of -15 degrees C .”

The Discoverer will comply with the requirements of 30 CFR Part 250.417, the IMO, the USCG and DNV. All drilling operations will be conducted under the provisions of 30 CFR Part 250 Subpart D, API RP 53, 65 Part 2 and 75 and othe r applicable regulations and notices including those regarding the avoidance of potential drilling hazards and safety and pollution control.
Such measures as inflow detection and well c ontrol, monitoring for loss of circulation and seepage loss, and casing design will be the primary safety measures. Primary pollution prevention measures are the contaminated and non-contaminated drain systems, the mud drain system, and the oily water processing system.

Structurally, this is comparable to Canmar drillships used safely and successfully in exploration campaigns in the Beaufort a nd Chukchi Seas into the 1990s.

Additional specifications on the drillship are provided in Attachment 2.

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 5 May 2011 Drillship Principal Dimensions

Dimension Discoverer

Length Overall 514 ft 156.7 m

Draft 27 ft 8.2 m

Width 85 ft 26 m



### Ice Management Vessels

Ice management support to the dr illship will be provided by the Fennica (or similar) and Tor Viking (or similar). The drillship will be supported by these IMVs from the beginning of the campaign until the vessel departs the area. A description of these vessels is provided in
Attachment 2.

Ice Management Vessel Principal Dimensions

Dimension Fennica Tor Viking

Length Overall 380 ft (116 m) 275 ft (83.7 m)

Draft 27 ft (8.4 m) 20 ft (6.0 m)

Width 85 ft (26 m) 59 ft (18.0 m)



### Primary Ice Management Vessel

The Fennica (or similar vessel) is designated as the primary IMV. The Fennica is classed by the DNV as +1A1. Designed for the management, maintenance and service of offshore oil wells, the 380-ft (116-m) Fennica is a multipurpose vessel specialized in marine construction and icebreaking. Fennica is equipped with dies el-electric propulsion syst ems and their innovative combination of capabilities, based on extensive design and engineering work, facilitates use of these systems in arctic conditions.

Secondary Ice Management Vessel / Anchor Handler

Tor Viking is designated as the secondary IMV and anchor handler. Designed for the management, anchor handling, and maintenance and service of offshore oil wells, the 275-ft (83.7-m) Tor Viking is a multipurpose vessel specialized in ma rine construction and icebreaking.

Guidance Note: IMVs supporting the drilling vessel may be deployed to assist other vessels, as operations and ice conditions di ctate. Diverting ice management resources away from the drilling vessel may require a curtailment of activities. This decision shall be made jointly by the Shell Drilling Foremen and the Master on the drilling vessel. The onshore Shell Drilling Superintendent (in consultation with the Noble Drilling Superinte ndent) will endorse the plan or set priorities if agreement cannot be reached at the field level.

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 6 May 2011 IV. SHELL ICE AND WEATHER ADVISORY CENTER

SIWAC is an integrated forecasting service st affed 24/7 by industry-leading specialists under Shell contract in Anchorage, Alaska. SIWAC’ s primary function is to provide current and
forecast ice and weather conditions directly to field operations a nd planning managers during the operational season. SIWAC provides information to decision makers and field principals to help them minimize risks when operating in the presence of ice. To provide quality and accurate information, SIWAC depends on skilled forecasters , subscription and pub lic satellite imagery, numerical models, field observati ons, Geographic Information System (GIS) software tools, and
a robust communication network.

SIWAC ICE DATA INPUTS

Ice forecasts are developed and issued daily. The Lead Ice Analyst compiles available data from subscription, specialized, and public services in ArcMAP (GIS Software) such as:

• MDA RadarSat 2 imagery

• MODIS satellite

• Canadian Ice Services

• National Ice Center

• Contract weather services

• Field observations

• IceNav images

Data Transmission

Effective communication of SIWAC ice and weather guidance and reciprocal feedback and field observations requires a robust and capable data network. The drilling vessel and IMVs are equipped with high-speed data and voice satellite service that has been proven to perform well in
the U.S. Chukchi and Beaufort Seas.

Data, including satellite imagery and observations, are relayed through a file transfer protocol (FTP) site between SIWAC and the field vessels us ing automated processes. This keeps both the field and forecasters continuously refreshed with the latest information. In addition, SIWAC maintains a secure website that allows direct, on demand access to all forecast reports and data products.

Additional information about SIWAC is in Attachment 3.

Ice Information Flow Chart

NOTE: The following graphic, Ice Manageme nt Communications Flow Chart, depicts the constant two-way communication that would o ccur between the various components of the
system.

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 7 May 2011 NOAA = National Oceanic and Atmospheric Administration BOEMRE = Bureau of Ocean Energy Management, Regulation and Enforcement



### Guidance Note: Additional information regarding ice may be requested by the Master of the drilling vessel. Any means appropriate to the circumstances shall be used to provide this
information. Where this information is to be obtained by aerial reconnaissance, the Shell Drilling Foreman will liaise with Shell Logistics to provide the appropriate resources. Ice Management Communications Flow Chart

Drilling Vessel SIWAC

Noble Drilling Superintendent Shell Drilling Superintendent BOEMRE National Weather Service

Climate Studies

Satellite Images NOAA + Canadian Ice Service

Fennica (or similar) Tor Viking (or similar)

IceNav

Drill site communications

Shore to drill site communications

Shore to shore- b ased communications

### Ice Management Plan Chukchi Sea, Alaska

Shell Gulf of Mexico Inc. 8 May 2011 V. ICE ALERT LEVELS AND PROCEDURES

These procedures define five Alert Levels that are linked to the time that hazardous ice is forecast to be at the drilling vessel location, a nd the time required to secure the well and move the drilling vessel off location if it becomes n ecessary. Roles, respon sibilities and actions required are specified according to the Alert Level.

Ice Alert Levels



### ALERT
LEVEL TIME CALCULATION STATUS

Green (HT – T-Time) is greater than 24 hours Normal operations

Blue (HT – T-Time) is greater than 12 hours and
less than 24 hours Initiate risk assessment. Validate
secure times and move times.

Yellow (HT – T-Time) is greater than 6 hours and
less than 12 hours Limited well operations in line with COCP. Commence securing
well.

Red (HT – MT) is less than 6 hours Well-Securing Operations Completed. Commence anchor recovery operations.

Black Drill site evacuated Move drilling vessel to a safe
location.

HT = Hazard Time
MT = Move-off Time
T-Time = Total Time

Guidance Note: If HT becomes greater than T-Time at any time, well securement and drill site evacuation contingency plans will be implemented.Ice Management PlanChukchi Sea, AlaskaShell Gulf of Mexico Inc.9May 2011Ice Alert Roles and ResponsibilitiesThe following table summarizes roles, responsibilitiesand actions required for each Ice Alert Level.AlertDrilling Vessel MasterDrilling Vessel IAIMV IA(Shell)IMV MasterNoble DrillingSuperintendentShell Drilling ForemanROLES ANDRESPONSIBILITIESFORALL ALERTLEVELSThe Drilling Vessel Master isthe person in charge (PIC) ofthe drilling vessel. He is thefinal authority in regards tosafety of the vessel, crew andcomplement. All changes ofAlert level are issued by theMaster. The responsibility toevacuate the drill site inresponse to a hazard rests withthe MasterEvaluates information fromSIWAC, IAs and VesselManagement Team (VMT)Establishes Ice Alert Leveland directs ice managementoperations.Establishes MTs inconjunction with the IMVMasters.Ensure Alert Level status isbroadcast to fleet andinternally throughout drillingvessel at intervals dependenton Alert Level or at change ofalert LevelCollates and evaluatesinformation from the SIWAC,IMV IAs and VMTAdvises Master in establishingIce Alert Level.Correlates Secure Time (ST)with information from rigoperations.Establishes HT and MT inconjunction with IMVs anddrilling vessel and advisesMaster and VMT.Works in conjunction with IAson IMVs to develop andestablish effective icemanagement strategies andadvises Drilling Vessel Master.Ensures current ice drift isbroadcast to fleet and liaiseswith SIWACThe IA is Shell’s representativeonboard the IMVs and is theprimary contact for allcommunications with the DrillingVessel Master. He advises the IMVMaster in executing the icemanagement strategies.Works in conjunction with Masterof IMVs to determine the local iceconditions and hazardous ice.Works in conjunction with DrillingVessel IA and Master of IMVs todevelop and implement effective icemanagement strategies.Provides feedback on effectivenessof strategyand reports anyanomalies pertaining to ice.The Master is the PIC of theIMVs. He is the final authority inregards to safety of the vessel,crew and complement.Evaluates advice from the SIWACand IA (drilling vessel & IMVs).Works in conjunction with IA ondrilling vessel and IA of IMVs todevelop and execute effective icemanagement strategies within thecapability of the vessel.Provides feedback on effectivenessof the strategy to the IA on theIMVs.Reports to IMVs IA any conditionwhich inhibits vessel performanceThe Noble DrillingSuperintendent is the on-sitesupervisor responsible for allrig functions and drillingrelated operations aboard thedrilling vessel.Establishes ST & informs VMTof ST and well conditions.Validates drilling team is awareof their duties under present IceAlert Level.Validates well securecontingency plansThe Drilling Foreman is the senioron-site Shell supervisor withresponsibility for overseeingdrilling and well operations and forinitiating spill response as the Onsite Incident Commander for spillsoriginating from the well site.Validates well ST in conjunctionwith the Rig Superintendent.Informs Drilling Vessel Masterand Noble Drilling Superintendentregarding ongoing & upcomingcritical operations and curtailmentplans.Communicates status of well andIce Alert level to Shell shore-basedmanagementUnder the authority of the ShellDrilling Superintendent the ShellDrilling Foreman may raise the IceAlert Level at any time, He mayorder the suspension of drillingoperations, securing of the well.Ice Management PlanChukchi Sea, AlaskaShell Gulf of Mexico Inc.10May 2011AlertConditionVMTCommsFrequencyDrilling Vessel MasterDrilling Vessel IAIMV IA(Shell)IMV MasterNoble DrillingSuperintendentShell Drilling ForemanGreen(HT – TTime) isgreater than24 hoursEvery 24hours, ormorefrequently asneededDischarges duties as peraccountabilitiesDischarges duties as peraccountabilitiesDischarges duties as peraccountabilitiesDischarges duties as peraccountabilitiesDischarges duties as peraccountabilitiesDischarges duties as peraccountabilitiesBlue(HT – TTime) isgreater than12 hours andless than 24hoursEvery 12hours, ormorefrequently asneededEnsures readiness to executecontingency plans.Ensures primary IMV is available toexecute Ice Management strategies forthe given ice regime.Ensures anchor handling tug supply(AHTS) IMV readiness to manage iceand anchor handling operations.Establish Ice Management Strategiesin conjunction with IMVs and IAonboard IMVs.Establishes Ice ManagementStrategies in conjunction with IMVMaster and Drilling Vessel IAValidate readiness of IMV toexecute ice management strategyExecutes Ice Management Strategiesin conjunction with IA on IMVsEstablishes and states readiness ofIMV to execute ice managementstrategyEstablishes ST and assessesupcoming well operationsfor changes to STInforms VMT of ST andwell conditionsValidates securingcontingency plansEvaluates ongoing &upcoming stage of drillingprogram with regard to STand COCPValidates ST in conjunctionwith the Rig SuperintendentInforms Drilling VesselMaster and Noble DrillingSuperintendent regardingongoing & upcoming COCPReports Alert changes toShell shore-basedmanagementYellow(HT – TTime) isgreater than 6hours and lessthan 12 hoursEvery 6hours, ormorefrequently asneededDirects ice management operationsEstablishes and Validates MTEstablishes departure strategyEnsures Alert status is broadcast tofleet and internally at 1-hour intervalsor at change of Alert LevelEstablishes HT & advises Master &VMTWorks in conjunction with IA onIMVs to initiate ice managementstrategiesEnsures current ice drift is broadcastto fleetImplements ice managementstrategies as directed by DrillingVessel Master in conjunction withIMV MasterProvides feedback on effectivenessof strategyExecutes ice management strategiesas directed by Drilling Vessel Masterand IA on IMVProvides feedback on effectivenessof the strategyCommences securing wellin accordance with agreedupon plan, informs VMT ofprogressMonitors Well SecuringOperations andeffectiveness of icemanagement operationsCommunicates overalldrilling vessel status to Shellshore managementRed(HT – MT) isless than 6hoursEvery hour Initiates departure plans followingconfirmation from Rig Superintendentthat lower marine riser package(LMRP) has been retrieved and securedand guide wires are releasedEnsures Alert Level status is broadcastto fleet and internallyDirects IMV and AHTS activitiesAssess effectiveness of IceManagement Strategy in line withongoing operations,Assist Drilling Vessel Master asneededEnsures current ice drift is broadcastto fleet during anchor recoveryoperationsContinues to implement icemanagement strategies in supportof drilling vessel and anchorrecovery operationsExecutes ice management strategiesand or activities associated withreleasing the drilling vessel frommoorings as directed by DrillingVessel Master and IMV IAConfirms well is securedand that LMRP isdisconnected, retrieved &securedCommences securing drillfloor for departure from siteMonitors rig securingoperations and departureplanCommunicates status toShell shore managementOrganizes additionalsupport as needed for sitedeparture operations (forexample logistics)BlackDrill siteevacuatedAs needed Directs IMV support operations leadingto safe departure from drill site to preagreed safe areaComplies with all regulatory reportingrequirements (internal and external)Works with VMT and IA and IMVs toestablish further course of actionContinues to monitor ice conditions.Works in conjunction with IA onIMVs during transitProvides Master of Drilling Vesseland VMT with information to aidfurther decision makingAdvises IMV Master on operationsleading to safe transit from drillsite to pre-agreed safe areaProvides information to DrillingVessel Master to aid furtherdecision makingWorks under direction of the DrillingVessel Master and IMV IA duringtransitConfirms drill floor andassociated areas are securedand ready to depart drill siteProvides information toMaster and VMT to aidfurther decision makingInforms Shell shoremanagement of evacuationComplies with all regulatoryreporting requirements(internal and external)Provides information toMaster and VMT to aidfurther decision makingIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 11 May 2011 VI. ICE MANAGEMENT PHILOSOPHY

An effective IMP is designed to enable execution of the exploration program, with the appropriate barriers in place to ma nage and mitigate against risks that are specific to exploration drilling operation in offshore Alaska (in this case, threat of ice). Additionally, the IMP identifies the “top” event caused by the failure of barriers and addresses the procedures to deal with consequences of escalation.

The “top” event, for the purpose of the IMP, is a yellow alert level that triggers the commencement of well suspension operations. This section addresses the activities associated with ice management as a barrier to the top event.

The strategy to prevent the top event is to have the following elements as effective barriers:

• proper equipment,

• skilled people,

• appropriate in formation, and

• work processes.

The key elements identified above are discussed herein.

Proper Equipment

• The IMVs will be capable IMVs, with the appropriate ice strengthening, and have been contracted to support the exploration campaign.

• IceNav: The drilling vessel and IMVs will be outfitted with IceNav Equipment (Enhanced radar imaging of ice)

• Tor Viking (or similar vessel) is a high specification anchor handling vessel and will be the primary anchor handling vessel.

• Fennica (or similar vessel) designated as the primary IMV has anchor handling capability and could be used to supplement Tor Viking if needed.

Skilled People

• The drilling vessel and IMVs will carry specialist IA, in addition to the regular crew complement.

• The drilling vessel and the Fennica (or similar vessel) w ill have two IAs onboard providing 24/7 coverage.

• The IAs supporting the exploration campaign will have documented experience of having performed ice management activities associat ed with supporting exploration activities.

• SIWAC will be staffed with world-class i ndustry-acknowledged experts in weather, satellite and Ice Synoptic analysis.

• IMVs will have crews with ice management experience.Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 12 May 2011 Appropriate Information

A multi-layered, systematic approach is taken to provide relevant information from SIWAC with a feedback loop from the vessels using:

• Wide Area Satellite Imagery

• High Resolution Satellite Imagery

• Meteorological Buoys

• Field Observation

• Numerical Models

• Local Radar

• Vessels are outfitted with Fit-for-Purpose Data and Communications link.

Work Processes

A systematic approach for risk mitigation is adopt ed by developing effective work processes.

• Development of effective ice management strategies based on available information (global and local)

• Deployment of assets to deliver strategy

o Threat sectors identified

o Assess manageability of ice feature

o Appropriate management of ice feature ( breaking/deflecting)

o Primary IMV deployed at an effective perimeter to reduce floes to manageable
size in advance of HT

• Scheduled VMT meetings (frequency dictated by Alert levels)

• Planning/Coordination meetings with specific focus on Ice Alert LevelsIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 13 May 2011 VII. WELL SUSPENSION PROCEDURES.

Effectiveness of the IMP depends on accurately establishing HT, ST and MT. Secure Time is time taken to secure the well, di sconnect and retrieve the LMRP.

As part of securing the well, well suspension procedures will be established. These procedures will supplement the detailed well securing proce dures that will be contained within the Rig Operations Procedures and will be specific to securing the well in response to the threat of
hazardous ice.

Return to the drill site following exit due to the th reat of hazardous ice is covered in Section IX.

Examples of well suspension options and pro cedures are presented in Attachment 4.

A. Well Suspension Options

Securing and suspending the well can be accomplished by several means. The base case is to suspend the well by plugging, (mechanical or cement). The chosen option or combination thereof will be dependent upon well conditions, environmental conditions, and (or) equipment limitations. Shell will employ the most effe ctive suspension procedure under the specific
circumstances at the time.

Relevant information associated with well suspension will be documented in the daily drilling reports. The BOEMRE field representative will be apprised, and relevant records will be
submitted to BOEMRE.

Potential well suspension options are listed in the following table.Ice Management PlanChukchi Sea, AlaskaShell Gulf of Mexico Inc.14May 2011Mechanical PluggingDrillpipe Hang-offPull Out of HoleShearing Drill PipeDropping StringTime Required /PreferenceRequires most time. Is thebase case procedure forsecurement.Less time than plugging Potentially less timedepending upon positionin hole.Least amount of time;Stuck pipecontingencyComparable toshearing drillpipe.Contingency to copewith mechanicalhoisting failureProvides WellboreIsolationYes Yes (blind/shears closed) Yes (blind/shears closed) Yes (blind/shearsclosed)Yes (blind/shearsclosed)Hang-off Sub(HOS) RequiredNo Yes (Emergency Drill PipeHang-off Tool)No No NoPackers / BridgePlug RequiredYes No No No NoPotential to LeaveString in HoleYes, if suspended belowpacker.Yes No Yes, but access topump through shearedstring is questionable.String in hole butrequires fishing tripand overshot tocirculateRemarksMechanical plugs are preferredmethod in cased hole.In this case no downholeplugging has been assumed.This method is acceptablein situations where casinghas been run andcemented, but not drilledout yet. Pipe can bepulled and blind/shearsclosed without furthercontainment.Contingency for stuckpipe situationContingency to copewith mechanicalhoisting failureAdvantages Provides complete wellboreisolation. Equipment readilyavailable.Provides wellbore isolationvia blind/shear rams.Equipment readily available.Can be done in a timelymanner. Leaves kill string inplace for potential wellcontrol requirements.Requires less time insituations where casinghas been run but notdrilled out, or if already outof the hole as notedabove, for logging orchanging BHA.Quickest way tosecure the well andprepare for move-offNext to shearing,quickest way toprepare rig for moveoff. Also leaves thetop of the string in thehole undamaged andready for recovery orcirculating via overshotand packoffDisadvantages Takes longer. Packers requireadditional tripping. Cementingrequires mixing / pumping timeand introduces potential forcontamination.No downhole wellboreisolation.Not a preferred methodwith open hole conditionsbecause no pipe is left inthe hole for potential wellcontrol methods. Nodownhole wellboreisolation.Potential to leave adeformed pipe profilecomplicating fishingand circulatingoperationsNo downhole isolationis accomplished.Requires fishing trip toreestablish downholecirculationIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 15 May 2011 VIII. MOORING SYSTEM RELEASE/ RECOVERY

A. Conditions Present to Initiate Mooring System Release and Recovery

This section addresses mooring system release an d recovery if ice conditions have triggered an Ice Alert Level of yellow and escalated to a red. The following discussion assumes the well has
been secured and all recoverable well-re lated equipment has been retrieved.

B. Release Options

Mooring system release /recovery can be accomplished by several means. The base case is to recover moorings in the conventi onal manner. The selection of a specific release option and the execution of the procedures rest with the Drilling Vessel Master who informs the VMT. Potential options are listed in the table below.

Mooring System Release/ Recovery

Conventional Anchor
Retrieval Rig Anchor Release (RAR) Running off Wires

Time Required /
Preference Requires most time. Is the base case procedure for retrieval Less time than conventional

recovery Contingency plan if RARs
fail to activate.

Advantages System is intact. Ready for redeployment Reduced MT None

Disadvantages None Increased redeployment time. Requires back up equipment. Potential loss of buoys. Relies on activation by
acoustic release. Complicates redeployment. High potential for seabed fouling. Potential to compromise system.



### IX. MOVING ONTO OR RETURNING TO THE DRILL SITE

The authority to move on to or return to the drill site will be issued by the Shell Drilling Superintendent with the concurrence of the Rig Manager. Relevant regulatory authorities will be notified in accordance with the requirements.

Upon authorization, the final decision to move on to or return to the dri ll site is dependent upon the Drilling Vessel Master and the VMT who are able to assess the various parameters properly with input from the IMV Masters and IA to determine the practicality of the decision.Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 16 May 2011 X. TRAINING

All personnel will be made aware of their role s and responsibilities within this IMP through a training session on each vessel. This training will include a table-top exercise, which will be executed prior to beginning operations to pr ovide exposure to and test communications and procedures of the COCP and the IMP. Participants at the table-top exercise will include:

• Shell and Drilling leadership

• Rig Crews (both Drilling and Marine Operations staff)

• Oil Spill Response (OSR) representative

• SIWAC representatives

• BOEMRE operations representatives

• IMVs

• IAs

• Alaska Logistics (Marine and Aviation) Representatives

Observations from the table-top exercise will be documented.Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 17 May 2011 XI. ATTACHMENTSIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 18 May 2011 

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### Shell Gulf of Mexico Inc. 19 May 2011 Attachment 1 – Extract from Crit ical Operations Curtailment Plan

Per Section 10 of the COCP:

Notification of the decision for curtailments re quiring the rig to disconnect from the well and depart location will be made as soon as practical, but not to inte rfere with the safety of the crew, environment, or vessel. This notification will be made either verbally to a representative on site or by telephone to a BOEMRE representative on duty; the notification may also be made in written form through the use of fax or email.

All operations curtailment decisions will be documented on the Shell Daily Operations Report. This information will be conveyed to BOEMRE on a weekly basis via the Well Activity Report and at the end of the well operations as part of the End of Operations Report.

The following flow chart depicts notifications in the event of curtailment.Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 20 May 2011 Curtailment Notification Flow Ch art (Attachment 1 continued)

USCG Shell Drilling Superintendent BOEMRE

Shell Ice
Weather Advisory Center Rig Manager

Shell Drilling

Foreman BOEMRE Representative

Master Drilling
Vessel Noble Drilling Superintendent Shell Drilling Engineers

Drilling Vessel

Ice Advisor

Fennica ( or similar ) Tor Viking ( or similar ) Support VesselsIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 21 May 2011 

## Attachment 2 - Vessel DescriptionsIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 22 May 2011 

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### Shell Gulf of Mexico Inc. 23 May 2011 Discoverer Specifications

DISCOVERER OPERATING WATER DEPTH

MAX WATER DEPTH 1,000 ft (305 m) with present equipment (can be outfitted to 2,500 ft [762 m])

MAX DRILLING DEPTH 20,000 ft 6,098 m DISCOVERER SPECIFICATIONS

TYPE-DESIGN Drillship - Sonat Offshore Drilling Discoverer Class

SHAPE Monohull with sponsons added for ice-resistance 1

SHIP BUILDERS & YEAR Namura Zonshno Shipyard, Osaka, Japan - hull number 355

YEAR OF HULL CONSTRUCTION 1965

YEAR OF CONVERSION 1976

DATE OF LAST DRY-DOCKING 2010

DISCOVERER DIMENSIONS

LENGTH 514 ft 156.7 m
LENGTH BETWEEN PERPINDICULARS (LBP) 486 ft 148.2 m

WIDTH 85 ft 26 m
MAXIMUM (MAX) HEIGHT (ABOVE KEEL) 274 ft 83.7 m

HEIGHT OF DERRICK ABOVE RIG FLOOR 175 ft 53.3 m

DISCOVERE R

MOORING EQUIPMENT
Anchor pattern symmetric 8 points system. The unit is fitted with Sonat Offshore Drilling patented roller turret mooring system giving the unit the ability to maintain favorable head ing without an interruption of the drilling operations

ANCHORS Stevpris New Generation 7,000 kilograms (kg) each (ea) 15,400 pounds (lb) ea

ANCHOR LINES Chain Wire Combination

SIZE/GRADE 2.75-in. wire 3-in. ORQ Chain

LENGTH 2,750 ft (838 m) wire + 1,150 ft (351 m) chain (useable) per anchorIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 24 May 2011 Table 1.c-2 Discovere r Specifications (continued)

DRAW WORKS EMSCO E-2,100 - 1,600 horsepower (hp)

ROTARY National C-495 with 49 1⁄2 -in. opening

MUD PUMPS 2 ea. Continental Emsco Model FB-1600 Triplex Mud Pumps

DERRICK Pyramid 170 ft. with 1,300,000 lb nominal capacity

PIPE RACKING BJ 3-arm system

DRILL STING COMPENSATOR Shaffer 400,000 lb with 18-ft (5.5 m) stroke

RISER TENSIONS 8 ea. 80,000 lb Shaffer 50-ft (15.2 m) stroke tensioners

CROWN BLOCK Pyramid with 9 ea. 60-in. (1.5 m) diameter sheaves rated at 1,330,000 lb

TRAVELING BLOCK Continental - Emsco RA60-6

BLOWOUT PREVENTOR (BOP) Cameron Type U 18 3⁄4 -in. (48 cm) x 10,000 pounds per square in. (psi)

RISER Cameron RCK type, 21-in. (53 cm)

TOP DRIVE Varco TDS-3S, with GE-752 motor, 500 ton

BOP HANDLING Hydraulic skid based system, drill floor

1 Sponsons designed and constructed to meet requirements of Det Norske Veritas (DNV) Additional Class Notation ICE-05. DISCOVERER DISPLACEMENT

FULL LOAD 20,253 metric tons (mt)

DRILLING 18,780 mt (Drilling, max load, deep hole, deep water)

DISCOVERER DRAUGHT

DRAFT AT LOAD LINE 27 ft 8.20 m

TRANSIT 27 ft (fully loaded, operating , departure) 8.20 m

DRILLING 25.16 ft 7.67 m

DISCOVERER HELIDECK

MAXIMUM HELICOPTER SIZE Sikorsky 92N

FUEL STORAGE 2 ea. 720-gallon tanks

DISCOVERER ACCOMODATIONS

NUMBER OF BEDS 140

SEWAGE TREATMENT UNIT Hamworthy ST-10

DISCOVERER PROPULSION EQUIPMENT

PROPELLER 1 ea 15 ft 7-in. (4.8 m) diameter, fixed blade

PROPULSION DRIVE UNIT Marine Diesel, 6 cylinder, 2 cycle, Crosshead type

HORSEPOWER 7,200 hp @ 135 revolutions per minute (RPM)

TRANSIT SPEED 8 knots

GENERAL STORAGE CAPACITIES

SACK STORAGE AREA 934 cubic meters (m3)

BULK STORAGE

Bentonite / Barite 180 m3 - 4 tanks

Bulk Cement 180 m3 - 4 tanks LIQUID MUD

Active 1,200 barrels (bbl)

Reserve 1,200 bbl

Total 2,400 bbl

POTABLE WATER 1,670 bbl / 265.5 m3 (aft peak can be used as add. pot water tank)

DRILL WATER 5,798 bbl / 921.7 m3

FUEL OIL 6,497 bbl / 1,033 m3Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 25 May 2011 Fennica SpecificationsIce Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 26 May 2011Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 27 May 2011 Tor Viking Specifications

AHTS/Icebreaker Tor Viking II- Main Characteristics Design: KMAR 808 AHTS/ ICEBREAKER (Now; MOSSMAR) Classification: DnV,+1A1, SUPPLY, SF, TUG ICEBREAKER ICE-10, DK(+) EO HELDK-SH DYNPOS-AUTR HL(2,8) W1-OC Built / Delivered: Havyard Leirvik, Norway - 03/2000 Registered / Flag: Skärhamn, Sweden

Dimensions Length Over All (LOA): 83.70 metres Length between p.p.: 75.20 metres Breadth, moulded: 18.00 metres Depth, moulded: 8.50 metres Draught (scantling): 7.20 metres Draught (design): 6.00 metres Freeboard (design): 2.50 metres Dead Weight: 2,528 tonnes Light Ship: 4,289 tonnes Gross: 3,382 tonnes Net: 1,145 tonnes

Capacities Dry Bulk: 283 m 3 in 4 tanks - totalling 10,000 ft 3
Pot Water: 724 m 3 Drill Water / Ballast: 1,205 m 3 Brine: 400 m 3 – SG 2.5 Oil Based Mud: 612 m 3 – SG 2.8 Base Oil: 242 m 3 Fuel Oil: 1,190 m 3 Marine Gas Oil (Diesel)
Urea: 94 m 3 Diesel Overflow: 21 m 3 with alarm Diesel Service / Settling: 2 x 20 m 3 Deck Load: Abt 1,350 ts Deck Area: 603 m 2 / 40.20 m x 15.0 m All products in dedicated tanks – no dual purpose tanks

Propulsion Main Engine: MAK 18,300 BHP - 4 eng (father/son) 2 x 3,840 kW + 2 x 2,880 kW = 13,440 kW Thrusters: Bow 1,200 BHP in tunnel (Electr) + 1,200 BHP 360 deg retractable = 2,400 BHP: Stern 1,200 BHP in tunnel Bollard Pull: Bollard Pull: 202 continuous (DnV certified) / Abt. 210 max pull Speed/Consumption: 16 knots – Abt. 42.7 MT / 24 hrs at 6.0 metres draught , 12 knots – Abt. 25.0 MT

Towing & Anchorhandling Equipment AHT Winch: Brattvaag towing/anchorhandling winch 400 ts pull / 550 ts brake holding caps AHT Drum: One of 1,400 mm dia. x 3,750 dia x (1,250 mm + 1,250 mm) length Wire Capacity: 2 x 1,900 metres of 77 mm wire or 2 x 1,650 metres of 83 mm wire AH Drum: One of 1,400 mm dia. x 3,750 mm dia. x 3,000 mm length Wire Capacity: 4,100 metres of 83 mm wire Winch Control: TOWCON 2000 Automatic Control with printer
Pennant Reels : One off 2 x 1,500 m of 77 mm wire or 2 x 1,300 m of 83 mm wire capacity : One off 3,400 m of 77 mm wire or 1 x 3,100 m of 83 mm wire capacity Large Reel Inner Core: 1,500 mm dia Cable Lifters: 2 x 76 mm and 2 x 84 mm onboard Chain Lockers: 2 x 129 m 3 / giving abt 2 x 6,000 ft of 3 inch chain Shark Jaws: 2 pairs of Karm Forks arranged for chain up to 165 mm dia / 750 ts SWL Inserts for handling of 65, 75, 85, 100, and 120 mm dia. wire/chain Stern Roller: One of 3,5 metres dia. x 6.0 metres length – SWL 500 ts Guide Pins: 2 pairs Karm Fork Hydraulic pins – SWL 170 ts

Deck Equipment Capstans: 2 x 15 ts pull Tugger Winches: 2 x 15 ts pull Smit Brackets: One bracket on B Deck Forward – SWL 250 ts Cranes: 1 hydraulic crane on fore cargo deck giving 6 / 12 ts at 20/10 m arm (360 degr) : 1 telescopic crane on aft cargo deck giving 1.5 / 3 ts at 15/10 m arm (360 degr) : 1 hydraulic crane on for-castle deck for stores etc Windlass: 1 hydraulic windlass / mooring winch. 2 declutch-able drums 46 mm K3 chain

Accommodation: Accommodation of a total of 23 persons, including crew. All accommodation equipped with air-condition and humidification facilities.

Dynamic Positioning The vessel is equipped with Kongsberg Simrad SDP 21 Redundant DP System – GreenDPIce Management Plan Chukchi Sea, Alaska



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### Shell Gulf of Mexico Inc. 29 May 2011 

## Attachment 3 – Shell Ice and Weather Advisory Center

Operational Support Overview

Safe and efficient offshore operations in the Arctic are contingent upon quality and timely ice and weather forecasts. Using state-of-the art sate llite technology, large areas of the Beaufort and Chukchi Seas are monitored remotely by the SI WAC to track and forecast movement of ice and make estimates of ice ty pe and concentration.

Synthetic Aperture Radar (SAR) instruments on board the RADARSAT 2 satellite are contracted to acquire necessary images of sea ice over area s of interest several times per week. These images are transmitted to ground st ations, processed, and made av ailable for analysis within hours of acquisition. Interpretation of the ice ed ge and features are performed by experienced specialists using powerful mapping software to pr oduce ice charts that are considerably more
detailed than those available from national ice centers. These charts are then distributed to operational personnel and planning managers.

Knowing the location and composition of the ice at any given moment is a valuable tool. However, it is important to forecast how the ice may change over time. A complementary component of ice forecasting is quality weather information. Weather conditions in the Arctic are among the most severe on the planet and can change dramatically over a short time. The National Weather Service does not provide measurem ents and forecasts that sufficiently resolve the conditions over small areas or short time spans in the Arctic offshore. Therefore, dedicated meteorologists with Arctic forecasting experi ence are employed full time to produce accurate snapshots of the current conditions and reliable forecasts of weather conditions into the future.

Using the Global Forecast System (GFS) numerical weather model as a starting point, the meteorologists produce a high resolution grid in proprietary modeling software of weather parameters, such as atmospheric pressure, wind speed, and wave heig ht that have been corrected
based on local observations and weather inst rumentation from Shell’s vessels at sea, meteorological buoys, and coastal weather stations . The result is a model that accurately reflects
current and forecast weather conditions over shor t distances in the Beau fort and Chukchi Seas, making marine operations and ve ssel transits safer and more responsible. Without this innovative forecast effort, weather products from ot her sources tend to describe the average or general conditions that one could expect over large areas, such as the entire U.S. Beaufort Sea, which results in reports of local conditions rarely matching what is forecast for the specific areas of operations.

The wind vectors, a set of points indicating the sp eed and direction of the wind distributed over the Beaufort and Chukchi Seas, and other output from the weather model are applied to the ice charts in the mapping software. This allows the ice analyst to assess the effect of wind and weather systems on the future movement and development of the ice.Ice Management Plan Chukchi Sea, Alaska



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### Shell Gulf of Mexico Inc. 31 May 2011 

## Attachment 4 – Well suspension Options and Contingencies

In all the following well suspension scenarios, the assumption is that a determination has been made by the Shell Drilling Superintendent, the Shell Drilling Foreman, the Drilling Superintendent, the Drilling Vessel Master and the VMT that a hazard exists and the well should be suspended. The Shell Drilling Foreman and the Drilling Superintendent in conjunction with the Shell Drilling Engineer and the Shell Drilling Superintendent will have analyzed the trip time, borehole stability, well control issues, oper ational parameters, depth of hole, and time available to decide upon the contingency step s most appropriate for well securement, and a detailed procedure will have been worked up. The Shell Drilling Foreman then presents the procedure to the BOEMRE Field Representative aboard the drilling vessel for comment and

concurrence.

Well Suspension Scenario 1 – Mechanical Plugging

1. After determining that the well should be suspended under the assumptions described above, the Shell Drilling Forema n orders the Noble Drilling Superintendent to stop all normal drilling operations and to commence circulating the hole.

2. The driller completes circulating at minimum a full “bottoms up.”

3. The drilling assembly is pulled out of the hole and a mechanical packer suitable to the last casing or liner size is made up on the bottom of the drill string.

4. The packer is tripped in the hole, set approximately 200 ft above the last casing or liner shoe depth and pressure tested.

5. Depending on actual water depth, sufficient pipe is pulled to enable having the end of the string 200 ft above the top of the packer wh en hung off in the wellhead via the hang-off sub (HOS).

6. A full-opening safety valve and an inside blowout preventer (BOP) are made up in the top of the drill pipe, and one additional joint is added above these valves. The HOS is installed in the top of this joint. (The full opening safety valve is left in the open position.)

7. The HOS assembly is run in the hole on drill pipe to land the HOS in the wellhead bowl.

8. The proper hydraulic fluid volume to actuate the BOP stack is confirmed by the Subsea Engineer and the system operating pressure is checked. Pipe rams in the BOP are closed on the HOS profile. The drill pipe is backed out from the HOS and the landing string is pulled from the riser. The blind/shear rams are closed and locked above the HOS. BOP failsafe valves are all left in the closed position.

9. The master bushings are removed and the riser spider is installed.

10. The diverter handling tool is made up a nd the diverter assembly is laid down.

11. The riser landing joint is made up into the slip joint inner barrel. The slip joint inner barrel is collapsed and the inner barrel is locked.

12. BOP stack functions are blocked, and the LMRP connector is unlocked.Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 32 May 2011 13. The LMRP is pulled off the top of the BOP with the block motion compensator and riser
tensioners.

14. Once the Shell Drilling Foreman has ascertained that the LMRP is released from the BOP, he advises the Drilling Vessel Master that he is free to initiate (or continue) mooring recovery and departure procedures.

15. The drill crew and Subsea Engineer pull the landi ng joint to surface. The landing joint, slip joint and riser are then layed down and the LMRP is secured on deck.

16. The Drilling Vessel Master confirms with the IA that the Ice Alert Level has reached “red” status (ice hazard is due to arrive w ithin 6 hours of completing anticipated mooring recovery time). The Drilling Vessel Master advises the Drilling Superintendent to have the Subsea Engineer shear guidelines loose from the top of the BOP guideposts and to
retrieve the lines to surface.

17. The drill floor and moonpool area are cleared an d inspected in preparation for mobilizing the drilling vessel.

18. All decisions and supporting facts are recorded on the Daily Report and issued to the BOEMRE, SIWAC, and the normal distribution list.

Well Suspension Scenario 2 – Drillpipe Hang-off

1. After determining that the well should be suspended, the Shell Drilling Foreman orders the Drilling Superintendent to stop all normal drilling operations and to commence circulating the hole.

2. The driller completes circulating at minimum a full “bottoms up.”

3. A pill of heavy, kill-weight drilling mud is mixed and spotted at total depth (TD), then the rig pulls the bottomhole assembly back into the casing such that the bit will be at least 200 ft above the shoe when the pipe has been hung off on the BOP rams.

4. After pulling the proper distance into the casing, a full-opening safety valve and an inside BOP are made up in the top of the drillpipe. (The full opening safety valve is left in the

open position.) One additional joint of drillpip e is added above these valves and all connections made up properly.

5. Drill pipe is added to the top of the single, but the connection at the hang-off point is not fully tightened.

6. The drill string is lowered back into the well with the loose connection positioned just above a pipe ram.

7. The proper hydraulic fluid volume to actuate the BOP stack is confirmed by the Drilling Superintendent and the system operating pressure is checked. Pipe rams in the BOP just below the loose drill pipe connection are closed. The drill string is lowered until all string weight is resting on the closed pipe ram. The loose connection is backed off and the remaining drill pipe is pulled from the riser. The blind/shear rams are closed and locked above the backed off drill pipe. BOP failsafe valves are all left in the closed position.

8. Proceed with steps 9 through 18 as indicated in Scenario 1 above.Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 33 May 2011 Well Suspension Scenario 3 – Pull Out of Hole:

It is assumed the wellbore is isolated from the formation (i.e., a casing string has been run and cemented, but not yet drilled out). A drilling assembly has been run in the hole to the top of

cement.

1. After determining that the well should be suspended, the Shell Drilling Foreman orders the Drilling Superintendent to pull out of the hole.

2. After pulling out of the hole, the proper hydraulic fluid volume to actuate the BOP stack is confirmed by the Drilling Superintendent and the system operating pressure is checked.

3. The blind/shear rams are closed and locked. BOP fail-safe valves are left in the closed position.

4. Proceed with steps 9 through 18 as indicated in scenarios 1 and 2 above.

Well Suspension Scenario 4 – Shearing Drill Pipe

It is assumed the drill string is stuck and unable to be pulled from the hole.

1. After determining that the well should be suspended, the Shell Drilling Foreman orders the Drilling Superintendent to circulate at minimum a full “bottoms up” (assuming circulation is possible).

2. While circulating, the Drilling Superintendent and the Toolpusher calculate the location of the drill string tool joints below the rotary.

3. Once circulation is completed the proper hydr aulic fluid volume to actuate the BOP stack is confirmed by the Drilling Superintendent and the system operating pressure is checked.

4. Pipe rams are closed under the nearest connection.

5. The drill string is slacked down until all string weight is resting on the closed ram or the string weight has been transferred to the point at which pipe is stuck.

6. The blind/shear rams are closed, shearing th e drill string above the hang-off point. The
blind/shear rams are locked closed. BOP fail-safe valves are left in the closed position.

7. The cut section of drill string is pulled to surface.

8. Proceed with steps 9 through 18 as indicated in scenarios 1 and 2 above.

Well Suspension Scenario 5 – Dropping String

It is assumed that there has been a failure to the rig’s hoisting capability; for example, failure of the drawworks to be able to pick up or position th e string by lifting, and an approaching hazard has been identified. (Dropping the string is norm ally associated with being unable to shear the pipe across the shear rams, whether it is in the form of drill collars or heavywall casing, etc., and comes into play more often with a dynamically positioned vessel in a “drive off” situation.) Under most all circumstances with encroaching ice (barring mechanical failure), there is adequate time to trip drill collars out of the hole if across the stack or to install a crossover and run casing past the stack on drill pipe and th en utilize a conventional hang-off tool.)Ice Management Plan Chukchi Sea, Alaska



### Shell Gulf of Mexico Inc. 34 May 2011

1. After determining that the well should be susp ended and the string dropped because of a mechanical failure, the Shell Drilling Foreman orders the Drilling Superintendent to
circulate at minimum a full bottoms up (if circulation is possible).

2. Once circulation is completed the proper hy draulic fluid volume to actuate the BOP annulars is confirmed by the Dr illing Superintendent and the sy stem operating pressure is
checked.

3. Operating pressure for both annulars is incr eased to maximum, and both annulars are
closed.

4. The string is slacked down until all string weight is supported by the closed annular
elements.

5. Elevators are unlatched.

6. Opening pressure is applied to the annular s, releasing their hold upon the string and allowing it to fall downhole.

7. The blind/shear rams are closed and locked. BOP failsafe valves are left in the closed position.

8. At this point, the BOP stack functions are bl ocked, and the LMRP connector is unlocked. The LMRP is pulled off the top of the BOP w ith the riser tensioners alone, allowing it to clear the BOP sufficiently to enable moving off location.

9. Note that in this circumstance the LMRP may be left hanging until the hoisting capabilities of the rig have been restored. Movement off location will thus have to take water depth into consideration and clearan ce between the bottom of the LMRP and the
seabed.

10. Once hoisting capabilities have been restored, proceed beginning with step 9 in the scenarios above to get the diverter and slip joint layed down and the LMRP secured on
deck.