Revised Outer Continental Shelf Lease Exploration Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. May 2011 

Appendix K 

Ice Management Plan 

 
Revised 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 Region 

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. ROLES AND RESPONSIBILITIES ........................................................................................................... 2

B. DEFINITIONS AND ABBREVIATIONS ................................................................................................... 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. WELL SUSPENSION OPTIONS ........................................................................................................... 13

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

A. CONDITIONS PRESENT TO INITIATE MOORING SYSTEM RELEASE AND RECOVERY .......................... 15

B. RELEASE OPTIONS ........................................................................................................................... 15

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

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

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

ATTACHMENT 1 – EXTRACT FROM CRITICAL OPERATIONS CURTAILMENT PLAN .......................................... 19

ATTACHMENT 2 - VESSEL DESCRIPTIONS ..................................................................................................... 21

ATTACHMENT 3 – SHELL ICE AND WEATHER ADVISORY CENTER ................................................................. 29

ATTACHMENT 4 – WELL SUSPENSION OPTIONS AND CONTINGENCIES ........................................................... 31

 
Ice Management Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. ii May 2011 

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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 Program. 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 appropriate 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 authority and accountability of the Master(s) of the 

vessels for the safety of their personnel and vessels 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 procedures. 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-based 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 Management, 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. Station keeping is accomplished using the 

turret-moored, 8-point anchor system. The underwater 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 drifting 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 resistance. 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 quality 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 other 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 control, 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 and 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 drillship 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 diesel-electric propulsion systems 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 marine construction and icebreaking. 

Guidance Note: IMVs supporting the drilling vessel may be deployed to assist other vessels, as 

operations and ice conditions dictate. 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 Superintendent) 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 staffed 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 and 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 public satellite imagery, 

numerical models, field observations, 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 using 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 Management Communications Flow Chart, depicts the 

constant two-way communication that would occur 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-based 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, and the time required to secure the well and move 

the drilling vessel off location if it becomes necessary. Roles, responsibilities 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 Plan 

Shell Gulf of Mexico Inc. 9 Ice Alert Roles and Responsibilities The following table summarizes roles, responsibilities and actions required for each Ice Alert Level. 

Alert Drilling Vessel Master Drilling Vessel IA IMV IA (Shell) IMV Master 

ROLES AND RESPONSIBILITIESFORALL ALERTLEVELS

The Drilling Vessel Master is the person in charge (PIC) of the drilling vessel. He is the final authority in regards to safety of the vessel, crew and complement. All changes of Alert level are issued by the Master. The responsibility to evacuate the drill site in response to a hazard rests with the MasterEvaluates information from SIWAC, IAs and Vessel Management Team (VMT) Establishes Ice Alert Level and directs ice management operations. Establishes MTs in conjunction with the IMV Masters.Ensure Alert Level status is broadcast to fleet and internally throughout drilling vessel at intervals dependent on Alert Level or at change of alert Level

Collates and evaluates information from the SIWAC, IMV IAs and VMT Advises Master in establishing Ice Alert Level. Correlates Secure Time (ST) with information from rig operations.Establishes HT and MT in conjunction with IMVs and drilling vessel and advises Master and VMT. Works in conjunction with IAs on IMVs to develop and establish effective ice management strategies and advises Drilling Vessel Master.Ensures current ice drift is broadcast to fleet and liaises with SIWAC

The IA is Shell’s representative onboard the IMVs and is the primary contact for all communications with the Drilling Vessel Master. He advises the IMV Master in executing the ice management strategies.Works in conjunction with Master of IMVs to determine the local ice conditions and hazardous ice.Works in conjunction with Drilling Vessel IA and Master of IMVs to develop and implement effective ice management strategies.Provides feedback on effectiveness of strategy and reports any anomalies pertaining to ice.

The Master is the PIC of the IMVs. He is the final authorregards to safety of the vesscrew and complement.Evaluates advice from the Sand IA (drilling vessel & IMWorks in conjunction with Idrilling vessel and IA of IMdevelop and execute effectimanagement strategies withcapability of the vessel.Provides feedback on effectof the strategy to the IA on IMVs.Reports to IMVs IA any conwhich inhibits vessel perfor
Ice Management Plan 

Shell Gulf of Mexico Inc. 10 

Alert Condition VMT Comms 

Frequency

Drilling Vessel Master Drilling Vessel IA IMV IA (Shell) I

Green 

(HT – TTime) is greater than 24 hours 

Every 24 hours, or more frequently as needed 

Discharges duties as per accountabilities 

Discharges duties as per accountabilities

Discharges duties as per accountabilities

Discharges daccountabili

Blue 

(HT – TTime) is greater than 12 hours and less than 24 hours 

Every 12 hours, or more frequently as needed 

Ensures readiness to execute contingency plans. Ensures primary IMV is available to execute Ice Management strategies for the given ice regime. Ensures anchor handling tug supply (AHTS) IMV readiness to manage ice and anchor handling operations. 

Establish Ice Management Strategies in conjunction with IMVs and IA onboard IMVs. 

Establishes Ice Management Strategies in conjunction with IMV Master and Drilling Vessel IA Validate readiness of IMV to execute ice management strategy 

Executes Ice in conjunctioEstablishes aIMV to execstrategy 

Yellow 

(HT – TTime) is greater than 6 hours and less than 12 hours 

Every 6 hours, or more frequently as needed 

Directs ice management operations Establishes and Validates MT Establishes departure strategy Ensures Alert status is broadcast to fleet and internally at 1-hour intervals or at change of Alert Level 

Establishes HT & advises Master & VMT Works in conjunction with IA on IMVs to initiate ice management strategies Ensures current ice drift is broadcast to fleet 

Implements ice management strategies as directed by Drilling Vessel Master in conjunction with IMV Master Provides feedback on effectiveness of strategy 

Executes ice as directed band IA on IMProvides feeof the strateg

Red 

(HT – MT) is less than 6 hours 

Every hour Initiates departure plans following 

confirmation from Rig Superintendent that lower marine riser package (LMRP) has been retrieved and secured and guide wires are released Ensures Alert Level status is broadcast to fleet and internally Directs IMV and AHTS activities 

Assess effectiveness of Ice Management Strategy in line with ongoing operations, Assist Drilling Vessel Master as needed Ensures current ice drift is broadcast to fleet during anchor recovery operations 

Continues to implement ice management strategies in support of drilling vessel and anchor recovery operations 

Executes ice and or activireleasing the moorings as Vessel Mast

Black 

Drill site evacuated 

As needed Directs IMV support operations leading 

to safe departure from drill site to preagreed safe area Complies with all regulatory reporting requirements (internal and external) Works with VMT and IA and IMVs to establish further course of action 

Continues to monitor ice conditions. Works in conjunction with IA on IMVs during transit Provides Master of Drilling Vessel and VMT with information to aid further decision making 

Advises IMV Master on operations leading to safe transit from drill site to pre-agreed safe area Provides information to Drilling Vessel Master to aid further decision making 

Works under Vessel Masttransit 
Ice 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 manage 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 information, 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) will have two IAs onboard 

providing 24/7 coverage. 

• The IAs supporting the exploration campaign will have documented experience of having 

performed ice management activities associated with supporting exploration activities. 

• SIWAC will be staffed with world-class industry-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 adopted 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 Levels 
Ice 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, disconnect and retrieve the LMRP. 

As part of securing the well, well suspension procedures will be established. These procedures 

will supplement the detailed well securing procedures 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 threat of hazardous ice is covered in Section IX. 

Examples of well suspension options and procedures 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 effective 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 Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. 14 May 2011 

Mechanical Plugging Drillpipe Hang-off Pull Out of Hole Shearing Drill Pipe Dropping String

Time Required / Preference 

Requires most time. Is the base case procedure for securement. 

Less time than plugging Potentially less time 

depending upon position in hole. 

Least amount of time ;Stuck pipe contingency 

Comparable to shearing drillpipe. Contingency to cope with mechanical hoisting failure 

Provides Wellbore Isolation 

Yes Yes (blind/shears closed) Yes (blind/shears closed) Yes (blind/shears 

closed) 

Yes (blind/shears closed) 

Hang-off Sub (HOS) Required 

No Yes (Emergency Drill Pipe 

Hang-off Tool) 

No No No 

Packers / Bridge Plug Required 

Yes No No No No 

Potential to Leave String in Hole 

Yes, if suspended below packer. 

Yes No Yes, but access to 

pump through sheared string is questionable. 

String in hole but requires fishing trip and overshot to circulate 

Remarks Mechanical plugs are preferred 

method in cased hole. 

In this case no downhole plugging has been assumed. 

This method is acceptable in situations where casing has been run and cemented, but not drilled out yet. Pipe can be pulled and blind/shears closed without further containment. 

Contingency for stuck pipe situation 

Contingency to cope with mechanical hoisting failure 

Advantages Provides complete wellbore 

isolation. Equipment readily available. 

Provides wellbore isolation via blind/shear rams. Equipment readily available. Can be done in a timely manner. Leaves kill string in place for potential well control requirements. 

Requires less time in situations where casing has been run but not drilled out, or if already out of the hole as noted above, for logging or changing BHA. 

Quickest way to secure the well and prepare for move-off 

Next to shearing, quickest way to prepare rig for moveoff. Also leaves the top of the string in the hole undamaged and ready for recovery or circulating via overshot and packoff 

Disadvantages Takes longer. Packers require 

additional tripping. Cementing requires mixing / pumping time and introduces potential for contamination. 

No downhole wellbore isolation. 

Not a preferred method with open hole conditions because no pipe is left in the hole for potential well control methods. No downhole wellbore isolation. 

Potential to leave a deformed pipe profile complicating fishing and circulating operations 

No downhole isolation is accomplished. Requires fishing trip to reestablish downhole circulation 
Ice 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 and 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-related 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 conventional 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 drill 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 roles 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 provide 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. ATTACHMENTS 

 
Ice Management Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. 18 May 2011 

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Ice Management Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. 19 May 2011 

Attachment 1 – Extract from Critical Operations Curtailment Plan 

Per Section 10 of the COCP: 

Notification of the decision for curtailments requiring the rig to disconnect from the well and 

depart location will be made as soon as practical, but not to interfere 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 Chart (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 Vessels 
Ice Management Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. 21 May 2011 

Attachment 2 - Vessel Descriptions 

 
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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-resistance1

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 

DISCOVERER 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 heading 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 anchor 

 
Ice Management Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. 24 May 2011 

Table 1.c-2 Discoverer 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 m3 
Ice Management Plan Chukchi Sea, Alaska 

Shell Gulf of Mexico Inc. 25 May 2011 

Fennica Specifications
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Shell Gulf of Mexico Inc. 26 May 2011 
Ice 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 – GreenDP 
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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 satellite technology, large areas of the Beaufort and 

Chukchi Seas are monitored remotely by the SIWAC to track and forecast movement of ice and 

make estimates of ice type and concentration. 

Synthetic Aperture Radar (SAR) instruments on board the RADARSAT 2 satellite are contracted 

to acquire necessary images of sea ice over areas of interest several times per week. These 

images are transmitted to ground stations, processed, and made available for analysis within 

hours of acquisition. Interpretation of the ice edge and features are performed by experienced 

specialists using powerful mapping software to produce 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 measurements and forecasts that sufficiently resolve 

the conditions over small areas or short time spans in the Arctic offshore. Therefore, dedicated 

meteorologists with Arctic forecasting experience 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 height that have been corrected 

based on local observations and weather instrumentation 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 short distances in the Beaufort and Chukchi Seas, 

making marine operations and vessel transits safer and more responsible. Without this 

innovative forecast effort, weather products from other 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 speed 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. 
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Shell Gulf of Mexico Inc. 30 May 2011 

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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, operational parameters, depth of hole, and time 

available to decide upon the contingency steps 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 Foreman 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 when 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 and 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 landing 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 within 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 and 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 drillpipe 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 hydraulic 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 the 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 the string by lifting, and an approaching hazard 

has been identified. (Dropping the string is normally 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 then 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 suspended 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 hydraulic fluid volume to actuate the BOP 

annulars is confirmed by the Drilling Superintendent and the system operating pressure is 

checked. 

3. Operating pressure for both annulars is increased 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 annulars, 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 blocked, and the LMRP connector is unlocked. 

The LMRP is pulled off the top of the BOP with 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 clearance 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.