Gorgon Emp Mobil Australia Jansz Io Drilling Oil Spill Contingency Plan (1)

8/18/2019 Gorgon Emp Mobil Australia Jansz Io Drilling Oil Spill Contingency Plan (1)

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MOBIL AUSTRALIA RESOURCES COMPANY PTY LIMITED

JANSZ-IO DRILLING

OIL SPILL CONTINGENCY PLAN For and on behalf of the Proponent

Document No: AUJZ-EDD-07-DR-511-R01-0070 Revision: 0

Revision Date: October 2011

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Oil Spill Conting ency Plan

AUJZ-EDD-07-DR-511-R01-0070 Jansz-Io OSCP REV 0 171011.doc Page 3 of 72

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How to use this OSCP

Sections 1-5 BACKGROUND INFORMATION AND EMERGENCY PREPAREDNESS

- Project Description

- Purpose, scope and legislative background of the OSCP

- Geographic description and the environmental sensitivities of the area- Characteristics of the oil and other substances which could be spilt

- Describes the organisation of the emergency teams and their functions

- Outlines the requirements for response planning

Section 6 DISCOVERING THE SPILL - FIRST ACTIONS AND NOTIFICATION

- Describes the initial actions needed when a spill has been sighted and contains:

o Alerting procedure and standard forms

o Internal and external contact numbers for reporting of spill

o Assessing response Tier (1, 2 or 3) and initial action checklists

o Process for initiating emergency management teams

- USE THIS SECTION FIRST IF AN OIL SPILL OCCURS

Section 7 SPILL RESPONSE

- Describes how to plan for the response giving:

o Priorities for responding

o Responsibilities of the combat agency

o Ways of assessing spill movement and deciding on strategies for response

o Way of accessing equipment and resources for response

o Descriptions of criteria which would result in escalation of response

Section 8 INCIDENT REPORTING

- Provides requirements for Incident Reporting

Section 9 WILDLIFE

- Provides guidelines for wildlife protection and rescue

Sections 10 WASTE MANAGEMENT

- Provides guidelines on managing waste

Section 11 SAFETY PLAN

- Outlines process and responsibilities for managing safety

Section 12 TERMINATION OF RESPONSE

- Decision to Terminate

- Final Actions

APPENDICES

- Proformas for reporting

- Other reference material


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CONTENTS

1. INTRODUCTION ...................................................................................................................... 9

1.1 Gorgon Project .......................................................................................................... 9 1.2 Proponent ................................................................................................................. 9

1.3 Jansz-Io Work Operator Scope ................................................................................. 10 1.4 Aim and Objectives of Plan ....................................................................................... 10 1.4.1 Aim ............................................................................................................................ 10 1.4.2 Objectives ................................................................................................................. 10 1.5 Using This Document ................................................................................................ 10 1.5.1 Scope ........................................................................................................................ 10 1.5.2 Document Interfaces ................................................................................................. 11 1.5.3 Document Revisions ................................................................................................. 11 1.6 Legislative Framework .............................................................................................. 11 1.6.1 Regulatory Requirements .......................................................................................... 11 1.6.2 National Plan ............................................................................................................. 11 1.6.3 WestPlan-MOP ......................................................................................................... 12 1.6.4 Responsibility for Managing Spills ............................................................................. 12

2. PROJECT AREA AND ENVIRONMENTAL CONDITIONS ..................................................... 14

2.1 Location .................................................................................................................... 14 2.2 Meteorological Conditions ......................................................................................... 14 2.2.1 Temperatures ............................................................................................................ 14 2.2.2 Seawater Temperature .............................................................................................. 14 2.2.3 Tides ......................................................................................................................... 15 2.2.4 Winds and Waves ..................................................................................................... 15 2.3 Environmental Sensitivities ....................................................................................... 15 2.3.1 Mangroves ................................................................................................................ 15 2.3.2 Intertidal Flats ............................................................................................................ 15 2.3.3 Rocky Shores ............................................................................................................ 16 2.3.4 Coral Reefs ............................................................................................................... 16 2.3.5 Seagrass Meadows and Algal Beds .......................................................................... 16

2.3.6 Marine Flora and Fauna ............................................................................................ 16 2.3.7 Wading Birds ............................................................................................................. 16 2.3.8 Turtles ....................................................................................................................... 17 2.3.9 Cetaceans ................................................................................................................. 17 2.3.10 Exmouth Gulf ............................................................................................................ 17 2.3.11 Matters of National Environment Significance ........................................................... 18 2.3.12 Heritage places ......................................................................................................... 18 2.3.13 Additional Information on sensitive areas .................................................................. 18 2.4 Hazard Identification and Risk Assessment .............................................................. 18 2.5 Hydrocarbons ............................................................................................................ 20

3. RESULTS OF SPILL TRAJECTORY MODELLING FOR SPECIFIC SCENARIOS ................ 22

3.1 Surface Spills ............................................................................................................ 22

3.2 Subsea Blowout ........................................................................................................ 22

4. RESPONSE TEAMS AND PREPAREDNESS ......................................................................... 24

4.1 Response Priorities ................................................................................................... 24 4.2 Response Team Structure and Responsibilities ........................................................ 24 4.2.1 Company Response Teams Roles and Responsibilities ........................................... 24 4.3 Statutory responsibilities ........................................................................................... 27 4.3.1 Tiered Response ....................................................................................................... 28 4.4 The Oil Spill Response Incident Control System (OSRICS) ...................................... 28 4.5 Communications ....................................................................................................... 30


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5. MARINE OIL SPILL RISKS AND RESPONSE TACTICS ....................................................... 31

6. DISCOVERING THE SPILL – FIRST ACTIONS AND NOTIFICATIONS ................................. 33

6.1 First Sighting of Spill – Initial Actions ......................................................................... 33 6.2 Emergency Activation Pathway ................................................................................. 35 6.3 Assessing the Response Tier Level .......................................................................... 36

6.4 Reporting .................................................................................................................. 37 6.5 Agency Contacts ....................................................................................................... 37 6.6 Initial Actions Checklists ............................................................................................ 38 6.7 Action Checklists ....................................................................................................... 41 6.8 Contact Directory ...................................................................................................... 41

7. SPILL RESPONSE .................................................................................................................. 42

7.1 Response Overview .................................................................................................. 42 7.1.1 Responsibility for Spill response ................................................................................ 43 7.1.2 Priorities for preparing to respond to a spill ............................................................... 44 7.2 Incident Action Plans ................................................................................................. 46 7.3 Surveillance and Monitoring ...................................................................................... 46 7.3.1 Tracking oil movement .............................................................................................. 47

7.3.2 Aerial Surveillance .................................................................................................... 49 7.3.3 Oil Sampling .............................................................................................................. 51 7.4 Responding ............................................................................................................... 51 7.4.1 Preparing to Respond ............................................................................................... 51 7.4.2 Offshore Response Methods ..................................................................................... 53 7.4.3 Onshore Response Methods ..................................................................................... 55 7.5 Equipment Available for Response ........................................................................... 56 7.5.1 National Plan Equipment ........................................................................................... 56 7.5.2 WestPlan MOP .......................................................................................................... 56 7.5.3 AMOS Plan ............................................................................................................... 57 7.5.4 Affiliate Assistance .................................................................................................... 57 7.5.5 Central database of response equipment (MOSES) .................................................. 57 7.5.6 Mutual Aid Agreement ............................................................................................... 57 7.5.7 Oil & Gas Producers Association .............................................................................. 57

7.6 Response Escalation Criteria .................................................................................... 57 7.6.1 ExxonMobil Role in Tier 2 or Tier 3 Response .......................................................... 58

8. INCIDENT REPORTING .......................................................................................................... 60

9. WILDLIFE PROTECTION AND RESCUE GUIDELINES ......................................................... 63

9.1 Rescue Principles ..................................................................................................... 63 9.2 Contact Details .......................................................................................................... 63

10. WASTE MANAGEMENT ......................................................................................................... 64

10.1 Storage and Disposal of Wastes ............................................................................... 64

11. HEALTH AND SAFETY PLAN ................................................................................................ 66

11.1 Site Safety Plan ......................................................................................................... 66 11.2 Personal Protective Equipment ................................................................................. 67

12. TERMINATION OF RESPONSE .............................................................................................. 70

12.1 Decision to Terminate ............................................................................................... 70 12.2 Final Actions.............................................................................................................. 70 12.3 Post Spill Environmental Monitoring and Restoration ................................................ 70

13. REFERENCES ......................................................................................................................... 71


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Append ices

Appendix A Forms

Appendix B EPBC Listed Matters of NES

Appendix C Guideline for Characterising Slicks at Sea Appendix D Collection of Oil Samples

Appendix E Dispersant Information and MSDSs

Appendix F MOSES List

Appendix G Functions the Incident Management Team

Appendix H Incident Management Team Checklists

Appendix I Shoreline Response Strategies

Appendix J Oil Spill Modelling


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ABBREVIATIONS/ DEFINITIONS

ABU Australian Business Unit (Chevron)

ADIOS Automated Data Inquiry for Oil Spill

AEMT Australian Emergency Management Team (Chevron)

AIP Australian Institute of Petroleum

AMOSC Australian Marine Oil Spill Centre

AMOS Plan Australian Marine Oil Spill Plan

AMSA Australian Maritime Safety Authority

AusSAR Australian Search and Rescue

CMT Crisis Management Team (Chevron)

Combat agency Agency with operational responsibility to respond to an oil spill in the marineenvironment in accordance with the relevant contingency plan.

CVX Chevron Australia Pty Ltd

DIMT Drilling Incident Management Team

DMP Department of Mines and Petroleum (WA)

DOT Department of Transport (WA)

DSEWPC Department of Sustainability, Environment, Water, People and Communities (Cth)

DWF Deep Water Frontier

EAPL Esso Australia Pty Ltd

EMDC ExxonMobil Development Company

EPA Environment Protection Authority

EPBC Act Environment Protection and Biodiversity Conservation Act 1999

ERP Emergency Response Plan

ERR Emergency Response Room

ESG Emergency Support Group (ExxonMobil)

ESGL Emergency Support Group Leader (ExxonMobil)

FC Forward Controller

FWADC Fixed Wing Aerial Dispersant Capability

HMA Hazard Management Agencies (WA Department of Transport)

IC Incident Manager

ICC Incident Control Centre

IMT Incident Management Team

JIUOA Jansz-Io Unitisation and Unit Operating Agreement

JIWO Jansz-Io Work OperatorLOR Leader of the Operational Response

MARC Mobil Australia Resources Company Pty. Ltd.

MARPOL International Convention for the Prevention of Pollution from Ships

MEP Marine Environment Pollution (AMSA)

MODU Mobile Offshore Drilling Unit (refers to the Transocean Deep Water Frontier Drill Ship)

MOSES Marine Oil Spill Equipment System

MSDS Material Safety Data Sheet


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NADF Non Aqueous Fluid

NATPLAN National Plan to Combat Pollution of the Sea by Oil and Other Noxious andHazardous Substances (January 20110)

NOPSA National Offshore Petroleum Safety Authority

OIM Offshore Installation Manager

OPGGSA Offshore Petroleum and Greenhouse Gas Storage Act, 2006OSCP Oil Spill Contingency Plan

OSRICS Oil Spill Response Incident Control System

OSTM Oil Spill Trajectory Modelling

POLREP Pollution Report

PPE Personal Protective Equipment

SITREP Situation Report

SOPEP Shipboard Oil Pollution Emergency Plan

Statutory Agency Has responsibility for overseeing response action for oil spills, for the institution ofprosecutions and the recovery of cleanup costs on behalf of all participating

agencies.TO Transocean (Operator of the Deep Water Frontier Drill Ship)

WA Western Australia

WestPlan-MOP Western Australian State Emergency Management Plan for Marine Oil PollutionJune 2010


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1. INTRODUCTION

1.1 Gorgon Project

Construction activities have commenced for the Gorgon Project which will develop gas reserves of theGreater Gorgon Area including the Jansz-Io field.

Subsea gathering systems and subsea pipelines will be installed to deliver feed gas from the Gorgon andJansz–Io gas fields to the west coast of Barrow Island. The feed gas pipeline system will be buried as ittraverses from the west coast to the east coast of the Island where the system will tie into the GasTreatment Plant located at Town Point. The Gas Treatment Plant will comprise three Liquefied NaturalGas (LNG) trains capable of producing a nominal capacity of five Million Tonnes Per Annum (MTPA) pertrain.

The Gas Treatment Plant will also produce condensate and domestic gas. Carbon dioxide (CO2), whichoccurs naturally in the feed gas, will be separated during the production process. The separated CO2 willbe injected into deep formations below Barrow Island. The LNG and condensate will be loaded from adedicated jetty offshore from Town Point and then transported by dedicated carriers to internationalmarkets. Gas for domestic use will be exported by a pipeline from Town Point to the domestic gascollection and distribution network on the mainland.

1.2 ProponentChevron Australia Pty Ltd (Chevron) is the unit operator under the Jansz-Io Unitisation and Unit Operating Agreement (UUOA)

1 (UUOA, 2009) and operator under all other related Gorgon Project commercial

agreements. Mobil Australia Resources Company Pty Limited (referred to in this document as“ExxonMobil”

2) is delegated operator responsibility by the parties to the UUOA, including Chevron, for

certain Jansz-Io work activities which are described in paragraph 1.3 below..

As the Jansz-Io work operator (JIWO), ExxonMobil has the primary responsibility (as between the partiesto the UUOA), using ExxonMobil systems and procedures, to prepare and submit all necessarydocuments and applications for drilling and to fulfill the requirements of all applicable legislation andobligations of the conditional environmental approvals granted to the Gorgon Project as they apply to theJansz-Io development drilling activities.

Therefore, in preparing the Jansz-Io Drilling Environment Plan (EP) and this Oil Spill Contingency Plan(OSCP), ExxonMobil as JIWO, is acting on behalf of Chevron in Chevron’s capacity as:

operator of the Jansz-Io Production Licences WA-36, 39 and 40-L (in relation to OffshorePetroleum & Greenhouse Gas Storage Act, 2009), and as

proponent of EPBC 2005/2184 (in relation to Environment Protection, Biodiversity &Conservation Act, 1999).

Once the drilling and completion of the Phase 1 Jansz-Io wells is complete, in accordance with theUUOA, all further operator responsibility for the Jansz-Io wells and the Jansz-Io development (includingall remaining construction, commissioning and production activities, surveillance and plug &abandonment) will be the responsibility of Chevron.

Close coordination and alignment between ExxonMobil and Chevron will be maintained on all aspects ofthe work including simultaneous operations, logistics and emergency response.

.

1 The parties to the UUOA are: Chevron Australia Pty Ltd, Chevron (TAPL) Pty Ltd, Mobil Australia Resources Pty Ltd, Shell

Development (Australia) Pty Ltd, BP Exploration (Alpha) Pty Limited, Osaka Gas Gorgon Pty Ltd, Tokyo Gas Gorgon Pty Ltd andChubu Electric Power Australia Pty Ltd.

2 The term “ExxonMobil” as used in this EP may also refer to Exxon Mobil Corporation, or to one of its affiliates, in addition to Mobil

Australia Resources Company Pty Limited and is used merely for convenience and simplicity.


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1.3 Jansz-Io Work Operator Scope

ExxonMobil, as the Jansz-Io Work Operator, will undertake the activities as set out of the UUOA. Insummary, these activities consist of the Phase 1 drilling and completion of the 10 Jansz-Io developmentwells and the conversion of the Jansz-4 appraisal well to a pressure monitoring well, as set out in theJansz-Io Field Development Plan submitted to the Joint Authority in support of the application for Jansz-IoProduction Licences.

This OSCP covers the oil spill response contingency measures which are in place in the unlikely eventthat an oil spill occurs during the Jansz-Io Phase 1 drilling activities.

1.4 Aim and Objectives of Plan

1.4.1 Aim

The aim of this plan is to have in place appropriate measures to minimise the impact of oil spills shouldthey occur during the Jansz-Io drilling activities. These measures rely upon co-operation between allstakeholders, familiarity with established rapid response procedures and observance of the range ofoptions available to response personnel, in the event of a marine oil spill incident.

This Plan is principally directed at guiding the actions of project personnel in response to an oil spill fromthe Transocean Deepwater Frontier drilling rig, or from a vessel within the immediate vicinity of the rig,during the drilling and completion of the Jansz-Io wells.

This plan defines;

priority actions to be taken in the event of a spill,

information on the influence of local meteorological and oceanographic conditions onmarine oil spills,

equipment and facilities available for containment, recovery and disposal of spilled oil,

the organisations responsible for responding to an oil spill, and

guidelines for monitoring the impact of oil spills on the environment and for subsequentclean-up.

1.4.2 Objectives

The objectives of this document are to:

Facilitate the protection of human life and safety.

Ensure that environmental impacts are minimised.

Clearly define areas of co-operation and support between the Statutory Agencies,Combat Agencies and the oil and gas industry funded arrangements.

Ensure a state of preparedness

Identify potential oil pollution sources.

Define procedures for reporting spills to the relevant authorities.

Define procedures for the efficient control of the spill source.

Direct the restoration of the environment, as near as is practicable, to pre-spillconditions.

This plan will be tested via oil spill response exercises involving responsible parties.

1.5 Using This Document

1.5.1 Scope

This OSCP details the overall coordination of response to an oil spill associated with the Phase 1 Jansz-Io drilling campaign in the North West Shelf, Production Licences WA-36-L, WA-39-L and WA-40-L. Itincludes organisational responsibilities, actions, reporting requirements, and resources available toensure the effective and timely management and response to an accidental oil or chemical spill resultingfrom the activities of the drilling campaign. This response plan is designed to enable a response tounexpected spills of any of the chemicals and hydrocarbons used in the normal course of operationsduring the Jansz-Io drilling campaign, including fuels, lubricants, non aqueous drilling fluids and chemicaladditives. Response to an unexpected release of reservoir hydrocarbons during the drilling activities isalso addressed.


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Training exercises will be conducted to prepare responsible parties should the OSCP need to be enacted.

The information contained in this plan is intended for use as a set of guidelines for the spill responders. Actual circumstances may vary and will dictate the procedures to be followed, some of which may not bein this plan.

1.5.2 Document Interfaces

This plan interfaces with the following documents:

Jansz-Io Emergency Response Bridging Documentation (ExxonMobil 2011(b))

Jansz-Io Environment Plan (ExxonMobil 2011(a) )

The Transocean Deep Water Frontier Vessel Safety Case Revision (DWF SCR, 2011)

Esso Australia Pty Ltd Emergency Response Manual (ERM V7)

ExxonMobil Oil Spill Response Field Manual (ExxonMobil, 2008)

ExxonMobil Development Company Emergency Response Guide (EMDC ER)

National Plan to Combat Pollution of the sea by oil and other noxious or hazardoussubstances (NATPLAN, 2011) (this plan is all encompassing as it describes thestructure and responsibility of the various jurisdictions.

This OSCP will be implemented using the proprietary ExxonMobil Operations Integrity ManagementSystems (OIMS). OIMS is adopted by all ExxonMobil subsidiaries worldwide. It contains 11 Elements

each of which has globally defined corporate expectations. These are implemented through formallydesigned and documented Management Systems. This provides for all the standard recognisedrequirements of safety management systems, including a process for continuous assessment andimprovement and managed overall through management leadership, commitment and accountability. ThisOSCP is consistent with and meets the requirements of OIMS Element 10, Community Awareness andEmergency Preparedness.

1.5.3 Document Revisions

Review and testing of this OSCP will be undertaken regularly throughout the campaign. This will includeboth desktop and live exercises involving ExxonMobil, Transocean and third party service providers. Afull programme is currently being developed but as a minimum ExxonMobil will conduct the followingexercises:

Prior to the commencement of drill operations (this may be a desktop or live exercise)

Annual desktop exercise Following a significant change in the plan or operating conditions.

1.6 Legislative Framework

1.6.1 Regulatory Requirements

This plan meets the requirements of applicable State and Commonwealth legislation as listed below:

Offshore Petroleum and Greenhouse Gas Storage Act, 2006 (Commonwealth)(OPGSSA);

Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009 (Commonwealth)

Petroleum (Submerged Lands) Act 1982 (WA);

Guidelines made by the Department of Mines and Petroleum (DMP) as theDesignated Authority of the Commonwealth Offshore Petroleum Act, 2006 (OPA).

This plan is also based on the Incident Control System (ICS) supported by the National Plan.

1.6.2 National Plan

This plan interfaces with and is designed in accordance with the requirements and expectations of theNational Plan to Combat Pollution of the Sea by Oil and Other Noxious and Hazardous Substances(NATPLAN). NATPLAN is administered by the Australian Maritime Safety Authority (AMSA). This is the


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overarching plan for oil spill response activities in Australia and sets out clear definition of theresponsibilities of the major participants of the plan, being:

The Commonwealth

The States and Northern Territory

Port Authorities and Corporations and

The oil industry.

NATPLAN details such matters as division of responsibilities amongst participants, contingency planningand access to Commonwealth equipment.

1.6.3 WestPlan-MOP

In Western Australia, the Western Australian Emergency Management Plan for Marine Oil Pollution(commonly known as WestPlan-MOP) supports the NATPLAN. WestPlan-MOP details the arrangementsbetween State government agencies and industry to combat marine oil pollution within Western AustraliaState Waters, within ports and on shorelines. It prescribes responsibilities and procedures, and provides abasis for coordination of resources in responding to oil spill events.

The Western Australian Marine Safety Business Unit of the Department of Transport (DoT) is the HazardManagement Agency (HMA) for oil spills in WA state waters as designated by the EmergencyManagement Regulations 2006. DoT also has statutory responsibility to respond to spills of oil fromvessels under the Pollution of Waters By Oil and Noxious Substances Act, 1987 (POWBONS).

WestPlan-MOP is also supported by the Port and Industry Oil Spill Contingency Plans, WA.

1.6.4 Responsibi lity for Managing Spills

NATPLAN outlines the responsibilities for managing oil spills. The organisation responsible depends onthe location and source of the spill.

For each area of responsibility a statutory and a combat agency is nominated. These are defined asfollows:

Statutory Agency: the agency having the statutory responsibility for marine pollution incidents intheir area of jurisdiction

Combat Agency: the agency having operational responsibility in accordance with the relevantcontingency plan to take action to respond to an oil or chemical spill in the marine environment

In some cases, the statutory and combat agencies will be the same agency.

Spills within state waters are managed by the relevant State or NT (within 3NM of the coast).

The Department of Mines and Petroleum (DMP) is the nominated ‘Statutory Agency’ for Western Australia. The Department of Transport (DoT) is the nominated Hazard Management Agency (HMA) andis thereby responsible for coordinating the State administration and operation of the WestPlan-MOP inconsultation with the State Emergency Management Committee.

Spills from Oil Industry activities

Operators of offshore exploration and production activities are responsible for responding to spills fromtheir facilities and pipelines. Therefore, for the Jansz-Io Drilling Campaign, ExxonMobil will be theCombat Agency and will call on additional support from the Australian Maritime Safety Authority (AMSA)as required. The Statutory Agency will be the Department of Mines and Petroleum (DMP).

Figure 1.1 shows the responsibilities for managing spills under NATPLAN.


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Figure 1.1 - Responsibil ities under NATPLAN


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2. PROJECT AREA AND ENVIRONMENTAL CONDITIONS

2.1 Location

The Jansz-Io Gas Field is located on the western flank of the Kangaroo Syncline in the offshoreCarnarvon Basin which extends from Geraldton in the south to Karratha in the north. It covers

approximately 535,000 km2 offshore and approximately 115,000 km2 onshore. The basin contains up to15 km

2 of phanerozoic, marine and fluvial, silicilastic and carbonate sediments.

The field is 70 km North West of the Gorgon Gas Field, 130 km North West of Barrow Island, 140 km eastof the Scarborough Gas Field and 250 km from Dampier, the nearest port on the coast of Western Australia. Water depths vary from 1200 to 1400 m. Figure 2.1 shows the location of the field in relation tothe North West Australian region and other parts of the Gorgon Project.

Figure 2.1 – Jansz-Io Location Map

2.2 Meteorological Conditions

Meteorological conditions at the Jansz-Io area are described in detail in the Jansz-Io Drilling EnvironmentPlan (ExxonMobil 2011(a)) and are summarised below.

2.2.1 Temperatures

The Bureau of Meteorology (BOM, 2007) records for Barrow Island which is approximately 147 km fromthe Jansz-Io wells show that mean daily maximum summer temperatures range from 33°C to 35°C withthe highest maximum temperature recorded 45°C. Mean daily maximum winter temperatures ranges from25°C to 26°C. Offshore temperatures in the permit area are likely to be less extreme.

Mean monthly rainfall ranges from 12 mm to 55 mm in summer with the highest mean monthly rainfall of65 mm occurring in June. The highest daily rainfall of 193 mm was recorded in the month of Decemberand almost certainly was a cyclonic storm.

2.2.2 Seawater Temperature

The seawater in the Jansz-Io area is strongly thermally stratified throughout the year and has apermanent and extensive thermal gradient that is the highest from around the 100-220m depth, but will

Jansz-Io FieldJansz-Io Field


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continue to persist too as deep as 500m. The near-surface seawater will attain a maximum temperatureof 30 – 31°C by late summer (February – April) and cooling to a minimum 22 – 23°C by late winter(August – October). The temperature difference between surface and the bottom is approximately 27°Cin the summer and 19°C in the winter. The seafloor water temperature will remain fairly constantthroughout the year at 4° C.

2.2.3 Tides

Astronomical tides on the NWS are semidiurnal and generally quite large, ranging from 0.95 m nearExmouth to more than 3 m on the inner shelf near Broome. Maximum spring tide amplitudes range from just over 2 m at Exmouth, 2.5 m at Onslow, 4.5 m at Dampier to nearly 6 m at Port Hedland. The increasein tidal amplitude from south to north is most marked north of the Montebello Islands, where the width ofthe continental shelf increases significantly (Heyward, et al 2000).

2.2.4 Winds and Waves

The climate is monsoonal with seasonal winds primarily from the south-southwest during the summer andtransitional spring months and is rarely from the north-west or north. During winter, the winds typicallyprevail from the easterly and south-easterly direction and remain rare from the north-west or north. Duringthe transitional autumn and spring month, the winds swing between the summer and winter patterns andsoutherly winds are quite common. Figure 3.6 shows the monthly distribution of wind direction as derivedfrom the nearest data location (coordinates 20° S, 115° E) sourced from the National Centre forEnvironmental Predictions (NCEP).

Of the five significant storm types which occur in the area (tropical cyclones, monsoonal surge, squalls,trade wind surge and tornadoes), tropical cyclones are clearly the most important for extreme wind designcriteria (except for deeper layer currents which are dominated by tidal forces). Tropical cyclones originatefrom south of the equator in the eastern Indian Ocean, and in the Timor/ Arafura Seas during the summermonths of November to May. Historical analysis indicates that on average about 1.4 cyclones shouldpass within 200km and about 4.9 cyclones pass within 1000km of the Jansz site each year. Tables 4.1 to4.6 provide wind, wave and current data from a study on metocean conditions for the Jansz 2 and 3 wells(EMURC, 2011)

2.3 Environmental Sensitivities

The Jansz-Io Environment Plan (EP) contains detail of the environmental considerations andmanagement of the risks from the drilling activities in the Jansz-Io region (ExxonMobil 2011(a))

In the unlikely event of a major oil spill, consideration is given to a greater area of risk. The North WestShelf region of Australia is divided into bioregions the most relevant of which to this drilling campaign arethe Pilbara and Carnarvon bioregions covering the coastline and islands from Shark Bay to Exmouth andfurther north to Port Hedland. The high marine biodiversity and recreational values of the area arerecognised at a national and international level (DCLM, 2006).

The coast of this region generally has low relief with gently sloping beaches, numerous headlands andmany offshore islands. The inner, near-shore marine waters of the region are relatively turbid, beingsubject to disturbance from strong tidal flows and to episodic runoff from adjacent rivers. The mid to outercontinental shelf waters are generally clear.

2.3.1 Mangroves

Mangroves are conspicuous and extensive in association with muddy substrates. They form wide forestsin some parts of the mainland shore, and small but sometimes complex mangroves are found in bays,and on the sheltered shores of many offshore islands. There are few places in the world wheremangroves occur in arid conditions. For this region, the mangroves are of great scientific importance. Thewhole mangrove system of the region is considered important in order to maintain nutrient cycles andproductivity of the coastal zone. Mangroves are sensitive to hydrocarbons and which can have significanteffects even at low concentrations. The organisms which breed in the mangroves are equally affected.The hydrocarbons can persist in the muddy soils for extensive periods where the lack of oxygen candelay the degradation process.

2.3.2 Intertidal Flats

Extensive intertidal flats usually back fringing mangroves. Besides their rich and diverse faunas ofburrowing invertebrates and their use as feeding areas for migratory birds, these intertidal flats arestrongly linked to the functioning of the mangrove ecosystems.


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2.3.3 Rocky Shores

In the central Pilbara, particularly the Dampier Archipelago, many shores are dominated by igneousrocks. Limestone shores are to be found in some places on the mainland coast, but more often on thecoastal islands. The sloping, intertidal zone of these hard substrate coasts is dominated by the growth ofrock oysters and associated fauna. Horizontal rock pavements are usually covered with algal growth andsupport diverse invertebrate faunas. The front edges of the rock platforms may bear coral growth and inmany cases there is extensive coral reef development in the sub-littoral zone. Due to clear water andmoderate wave action, the floral and faunal composition and community structure of rock platforms on theoffshore islands (such as Barrow, the Montebellos, the Muirons and the outer islands of the Dampier Archipelago) differ significantly to those of the inner islands and mainland shores, where waters are moreturbid.

2.3.4 Coral Reefs

Coral reefs of the region include offshore coral banks and platform reefs of the West Pilbara, andextensive fringing reefs, such as those of the Dampier Archipelago, the Montebellos, the Muirons andother offshore islands. In addition, a wide variety of turbidity-adapted coral communities are found ininshore (DEC, 2002). The Ningaloo reef is an extensive fringing barrier reef system, extendingapproximately 300 km southward from the tip of North West Cape to Quobba and hosts very diverse coraland fish communities. The Ningaloo Reef is managed as a Marine Reserve, corals spawn in the regionpeaking between March and April and usually occurs over 7–10 nights after the full moon. Somespawning also occurs in October and November. Corals are most susceptible to oil spills during spawning

where coral eggs would come into direct contact with any hydrocarbons on the surface. Inshore corals inintertidal regions are also more susceptible to direct contact if hydrocarbons reach the shoreline.

2.3.5 Seagrass Meadows and Algal Beds

Tropical seagrass meadows may occur in the shallows, in lagoons, mangrove swamps and aroundislands, but are not as extensive as off the west and south coasts of the State. Seagrass and algal bedsare an important element of the region’s ecosystems and they support diverse fauna includingherbivorous fishes, turtles and dugongs.

2.3.6 Marine Flora and Fauna

Although many of the marine species occurring on the North West Shelf are widespread across the Indo-West Pacific region, there is still a significant degree of local endemicity. The fish, invertebrate and marineplant communities of the near-shore reefs, banks and tidal flats differ in composition from those of theshelf-edge atolls and offshore islands. These differences between inner and outer shelf biota are largely

due to the very different habitats provided by the turbid waters inshore and the clear oceanic conditionsoffshore. The fauna and their respective habitats which would be most sensitive to oil spills in the regionare:

2.3.7 Wading Birds

A number of wading birds use the region to roost and feed in the intertidal mudflats. Sea birds have ahigh risk of contact to spilled oil due to the amount of time they spend on or near the surface of the seaand on oil affected foreshores. Sea birds may also come in contact with spilled oil while searching forfood, since several species of fish are able to survive beneath floating oil. When birds become oiled thethermal properties of their feathers are affected. The birds’ buoyancy is also affected. Birds will try andremove the oil by preening themselves causing ingestion of toxic compounds which may have lethal orsublethal effects depending on the composition of the oil. Non wading birds can also be affected but areat less risk than wading birds. Barrow Island and the Exmouth Mangroves are listed as being ImportantBird Areas supporting significant bird communities (IBA, 2005).

Two endangered bird species listed in the EPBC Protected Matters database may occur in the region(SEWPAC 2011(b)) (see Section 2.3.11). The Tristan Albatross does not have any known nesting sightsin Australia and there has been only one definitive record of the Tristan Albatross from Australian waters;off the east coast of Australia near Wollongong. As the Tristan Albatross is an oceanic, pelagic feeder itmay occur in the region.

The Southern Giant Petrel has known nesting sites in the antarctic and subantarctic Islands of Australia,predominantly Macquarie, Heard and McDonald Islands. It is an opportunistic scavenger and predatorand will seize food off the surface of the water as well as scavenge on shorelines. The Southern GiantPetrel remains in the Antarctic regions during the summer period however during the winter monthsdisperses more widely up to at the Tropic of Capricorn (23 deg south)(SEWPAC 2011(c)). The SouthernGiant Petrel may occur in the region during the winter period.


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2.3.8 Turtles

Based on a search of the Department of Sustainability, Environment, Water, Population and Communities(SEWPAC) EPBC Act Online Protected Matters Database (SEWPAC, 2011), five species of marineturtles or their respective habitats may occur in the region of the Jansz-Io drilling. These are as follows:

Scientifi c Name Common Name

Dermochelys coriacea Leatherback (or Leathery) turtleChelonia mydas Green turtle

Natator depressus Flat-back turtle

Eretmochelys imbricate Hawksbill Turtle

Caretta caretta Loggerhead Turtle

Under the EPBC Act the Leatherback and Loggerhead are listed as endangered and the Green, Flat-backand Hawksbill turtles are listed as vulnerable (Also refer Section 2.3.11). All these turtle species are listedas migratory species under the EPBC Act and also under the Convention of Migratory Species (CMS)(Bonn Convention) with the exception of the Flatback turtle.

Apart from when turtles are nesting and are ashore, turtles are oceanic. Nesting is generally confined tospecific nesting sites. On the north-west shelf region of Western Australia nesting (depending on species)generally occurs from September to April (Pendoley, 2005). The nearest marine turtle nesting ground tothe Jansz-Io drilling area is on the west coast of Barrow Island, approximately 140km from the nearest

drill centre. Nesting of turtles also occurs on other islands in the region and along the mainland coast fromthe Kimberly Coast through to Shark Bay in the south. All the turtle species shown above have knownnesting sites in Western Australia except for the Leatherback turtle. Leatherback turtle nesting is known tohave occurred in the Northern Territory.

The green turtles are herbivores, feeding on macro-algae and seagrass beds in shallow waters. Flat-backturtles are carnivorous, foraging often around coral reefs. Loggerhead Turtles are also carnivorous,feeding primarily on benthic invertebrates in habitat ranging from near-shore to 55 m.

The Leatherback is the most pelagic of all the marine turtles and mostly feeds on gelatinous organismssuch as jellyfish.

Marine turtle nesting beaches occur through the region and in particular on the islands. If oil presents onbeaches turtles are vulnerable during the breeding season. Although little is known about the effects of oilon turtles, problems could occur on nesting beaches through absorption, ingestion and general oiling.

Marine turtles are of general concern due to the decrease in worldwide population numbers.2.3.9 Cetaceans

Dugongs occur in the region particularly in the shallow waters of the Rowley Shelf. Dugongs are fullyherbivorous and feed on sea grass beds in shallow waters. Therefore their habitats are low energyinshore regions of coastline that support seagrasses. As dugongs surface to breathe it is thought that oilthat is on the surface of the water can foul the airways, sensory hair and eyes. Toxicity could also occurthrough ingestion.

The Humpback whale is the most common whale which migrates through the region, often using the calmwaters of the Exmouth Gulf as resting grounds. Whales and other cetaceans face similar threats from oilas dugongs. However like the dugongs, there is little documented evidence of oil impact on whales due totheir highly migratory nature. The way a cetacean consumes its food affects the likelihood of its ingestingoil. For example, baleen whales, which skim the surface, are more likely to ingest oil than gulp feeders ortoothed whales such as dolphins (AMSA, 2011). The Blue Whale and Southern Right Whale, due to their

migratory nature, may occur in the region (SEWPAC 2011(b)). Both these are listed as endangered in theEPBC Protected Matters database (see Section 2.3.11).

2.3.10 Exmouth Gulf

Exmouth Gulf is the largest embayment in the region. The waters of the Gulf are generally turbid. Itseastern and southern shores are dominated by mangroves and mudflat habitats of great importance fornature conservation and for sustaining local fisheries. A range of mangrove species and mangrovesassemblages are present in the Gulf. Extensive seagrass beds may be found in shallow waters of theGulf, which provide feeding habitat for turtles and dugongs. The shores and near-shore habitats of thewestern side of the Gulf are quite different to those of the east.


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2.3.11 Matters of National Environment Significance

Matters of national environment significance (NES) listed under the Environment Protection andBiodiversity Conservation Act (EPBC) occur in the region. The full list of relevant species are shown in Appendix B, those which are endangered and may occur in the region are shown in Table 2.1 below, Allthese species, except for the birds, are also listed as migratory (SEWPAC, 2011).

Category Species Common Name

Birds Diomedea exulans exulans Tristan Albatross

Macronectes giganteus Southern Giant-Petrel

Migratory

Cetaceans

Balaenoptera musculus Blue Whale

Eubalaena australis Southern Right Whale

Reptiles Caretta caretta Loggerhead Turtle

Dermochelys coriacea Leatherback Turtle

Table 2.1: Listed Endangered Species from the Matters of National Environmental Significancedatabase (SEWPAC, 2011)

2.3.12 Heritage places

Two places in the region are listed as National Heritage Places under the EPBC Act. These are theNingaloo Coast (over 330km from the Jansz-Io area) and Shark Bay (over 700km from the Jansz-Ioarea). Both these regions are significant tourist precincts. Shark Bay is also listed as a World Heritage siteand Ningaloo has also just been accepted as a World Heritage site. Barrow Island and the Montebello-Barrow (more than 130 km to the south-east) have been nominated as National Heritage places and arecurrently Class A Nature reserves.

2.3.13 Addit ional Information on sensiti ve areas

Sensitive marine and coastal areas identified by various agencies are described in the GIS based Oil Spill

Response Atlas (OSRA) maintained by the WA Department of Transport (DoT).

OSRA identifies marine and foreshore ecosystems and biological resources for the determination ofprotection priorities and provides information on response options including:

boom deployment

chemical dispersant use

foreshore cleanup techniques to be employed

disposal sites for wastes generated.

Access to OSRA and its tools is via the State/NT ESC, State/NT OSRA Coordinator or State/NT Chair. AMSA has holdings of the data for emergency purposes.

The Department of Sustainability, Environment, Water, People and Communities (SEWPAC) can adviseon potential impacts of oil spills on threatened marine and migratory species, such as seabirds, seals,

marine turtles, whales and dolphins.

2.4 Hazard Identif ication and Risk Assessment

An assessment of all potential releases (including controlled and uncontrolled hydrocarbon, chemical andmud releases) was conducted in the Environmental Hazard Identification and Risk Assessment (HAZID)conducted for the Jansz-Io drilling campaign (as attached to the Environment Plan, ExxonMobil 2011(a)).The assessment found that in all potential spill scenarios, the residual risk to the environment wasassessed to be as low as reasonably practicable (ALARP). The Environment Plan discusses thesehazards in more detail. Releases to sea are most likely to occur (if at all) during bulk transfer operationsfrom the supply vessel to the rig.


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Chemicals

All chemicals to be used for the campaign will be transported to the rig in either drums (for liquids) or bags(for solids). These will be transported on pallets within sea containers which are certified (DNV orequivalent) for sea transport and lifting. The containers will be lifted and transferred across from thesupport vessel to the DWF. If dropped in the sea, the container would sink and be retrieved. If the integrityof the container was compromised it is unlikely that more than one or two drums would be damaged andcontents discharged. Under such circumstances the discharged substance would quickly disperse giventhe water depth and open ocean conditions. In this situation spill response would be minimal, and wouldlikely involve monitoring and possibly (although unlikely) physical break up to aid dispersion if any of thesubstance remained on the surface.

If the sea container were dropped on either the support vessel or DWF during transfer operations anyspillage would be contained on the vessel.

ExxonMobil assesses that the probability of such an event is deemed to be very low (dropping thecontainer + loss of integrity + release to environment).

Non Aqueous Drilling Fluid

Non aqueous drilling fluid (NADF) is a low-toxicity non-aqueous fluid required to maintain boreholestability while drilling all intervals below 20 inch surface casing. The Transocean Deep Water Frontier(DWF) Mobile Offshore Drilling Unit (MODU) will be equipped to properly process and handle the NADF

and discharge of the cuttings will be in accordance with Australian government regulations andExxonMobil Development Company (EMDC) worldwide practices.

The NADF consists of base oil and other additives (e.g. brine, emulsifiers, viscosifiers, weighting agents).The mixing ratio and concentration of all these products is dynamic. The NADF properties are monitoredand modified accordingly to maintain desired specifications to achieve a safe and efficient operation.

The Jansz-Io program will use Saraline 185V as the base fluid (CHARM rated D) as has previously beenaccepted for use in Western Australia. Saraline 185V will be mixed with various additives until the mudreaches the specification required. Generally a mix consists of approximately 60% base fluid and 40%additives. Approximately 3.6% (volume by volume) of this whole NADF is made up of the chemicals whichdo not have an OCNS/CHARM rating. The remaining components, making up approximately 96% of thewhole NADF, all have a low toxicity OCNS/CHARM rating (refer to Environment Plan for additionalinformation). Additional mixing of the NADF to the desired consistency occurs on the rig. NADF(predominantly Saraline 185V and approximately 96% CHARM rated Gold or Silver OCNS D or E) is

transferred in bulk, the chemical additives are transferred in drums or bags as described in the sectionabove.

Transfer of bulk NADF will be conducted by hose from the supply vessel to the DWF. Bulk transfers to therig are undertaken using strict procedures which include the following controls:

Daylight transfers (night transfers by exception and under strict additional controls)

Suitable weather conditions

Observers to watch for failures

Dry break couplings

Automated shut off pumps

The volume being transferred is measured and monitored from the pump room where any loss

will result in a corresponding loss of pressure. The engineer would see the loss of pressure andinstruct pumps to be stopped.

Given these controls measures, if a failure occurred during transfer operations the likely volume of liquidlost would equate to that of the hose volume (estimated at 445L (2.8 bbls) for a 55m (180 ft) hose).

As described in the Environment Plan, Saraline 185V has a CHARM rating of D due to its low toxicity. IfSaraline 185V was hypothetically released, any components remaining on the surface would form asheen and rapidly evaporate.

NADF usage for the Jansz-Io drilling campaign has a range of controls associated with it from theselection of low toxicity, CHARM/OCNS rated constituents where available, engineered preventativemeasures (equipment) and strict procedures on cuttings management, waste management and transferoperations. Due to the remote location of the drilling activity, water depth and open ocean sea conditions


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the likely response to a spill would be to monitor and possibly physically breakup any sheen thatremained on the water surface to facilitate evaporation and dissipation. It is unlikely that any other type ofresponse would be warranted. There are no sensitive environments in the immediate area that wouldneed protecting. The risk of spilling NADF is considered to low risk given the number of controls in place.

2.5 Hydrocarbons

Reservoir Hydrocarbons

In considering the fate of spilled hydrocarbon, the characteristics of the hydrocarbon must be understoodto understand how it is likely to react in the environment. Non- persistent hydrocarbons disappear rapidlyfrom the water surface whereas persistent hydrocarbons dissipate more slowly.

The presence and composition of hydrocarbons in the Jansz-Io field has been assessed during thedrilling of Jansz-1, 2 & 3 & 4 and Io 1 & 2. Jansz-Io hydrocarbon is primarily gas with less than 0.0001%liquid component (gas to oil ratio (m3:m3) of 35,213:1) of condensate. The hydrocarbon expected to beencountered during the Jansz-Io drilling campaign is expected to be of the same composition.

Hydrocarbons used in operations

In addition to the chemicals and NADF discussed above, the following hydrocarbons are used during thenormal course of drilling operations:

Jet Fuel Utility / hydraulic oils

Diesel

Diesel is the only one of these hydrocarbons which is transferred in bulk from the supply vessel to the rigand presents a relatively higher risk of spill on the Jansz-Io drilling campaign (although still assessed tobe low risk).

Table 2.2 provides additional information on the properties of reservoir and operational hydrocarbonswhich determine the likely behaviour of the product should a spill occur.

In the unlikely event that an uncontrolled release of condensate or diesel occurs, it is important tounderstand the properties and fate of the hydrocarbon. Condensate and diesel releases are discussed indetail in Section 3.


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Table 2.2: Description of reservoir and operational use hydrocarbons

Oil Type Descriptio n

Condensate Primary data collected in offset wells indicates that fresh/ unweathered condensate

has a low pour point (-54 C) and a density relatively lower than light crude oil (API47.7).

Approximately 38% of the oil by mass can be classed as low volatility and 12%classed as non-volatile at local ambient temperatures.

Weathering predictions under prevailing conditions using (worst-case) sea-watertemperatures indicate that condensate spilled onto the water surface would undergoa steady rate of evaporation over a number of days, which would then slow andcease with approximately 12% of the oil mass remaining as a residue. Under lightwinds (5 knots), total loss of all volatiles is expected to take about 48 hours.

Condensate is volatile and contains a number of toxic components and modellingsuggests that these aromatic hydrocarbons can persist in the environment topotentially cause damage to flora and fauna.

Jet Fuel Jet fuel is a kerosene derivative. It is lighter than diesel with a usual flash point of+38°.

Jet A1 liquid will spread into a sheen, evaporate and degrade rapidly. There shouldbe no emulsion. The liquid evaporates quickly and can ignite leading to a flash fire, oran explosion in a confined space.

Jet A1 contains some middle distillates which have the potential to causeenvironmental harm.

Utility / hydraulic oils There will be some utility / hydraulic oils which will either be transported via vessel orin the case of hydraulic oil will be contained within control lines for well control. Theoils are usually relatively viscous and not easily assimilated by the environment.

Expect limited spread and minimal loss through evaporation and natural dispersion.The action of mixing energy is likely to produce a frothy emulsion.

Utility oils present little danger to aquatic life but experiments have shown thatingestions of large amounts (e.g. by turtles) may cause abdominal pain anddiarrhoea.

Diesel

Diesel will be used as the main fuel source on the Deepwater Frontier andalso for the supply vessels

A mixture of volatile and semi-volatile hydrocarbons and would spreadrapidly and form a very thin slick if spilled at sea. The evaporation times arerapid and 40-50% of the mass predicted to evaporate within a day. The rateof evaporation of the semi-volatile components is dependant on weatherconditions (APASA, 2011).

Due to its toxic component, diesel still has the potential to causeenvironmental harm but is less persistent than other marine grade fuel oils

Properties

Viscosity (cP) 11.5

Flash Point (deg C) 37

Density (kg/m3) 0.829

Boiling point (oC) 464


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3. RESULTS OF SPILL TRAJECTORY MODELLING FOR SPECIFIC SCENARIOS

APASA was commissioned to conduct spill trajectory modelling for spills from the Jansz-Io region to allowa better understanding of the probable fate of an oil spill under certain conditions and to enableappropriate response planning to take place [refer to Appendix J].

3.1 Surface Spills

Two hypothetical spill scenarios: 500 Tonnes of diesel fuel oil (2 hours duration) and 1,000 Tonnes oflight crude oil (12 hours duration) were modelled in 2005.

Estimates of risk were calculated for two major wind seasons, summer and winter. The modelling studyindicated a very low risk of exposure to any shorelines or emergent reefs within the region during eitherseason. None of the simulated spills approached within 60 km of landfall under summer winds, or within100 km under winter winds. There was a large difference in the direction that slicks were expected to driftbetween the seasons. Under summer winds, slicks are most likely to drift to the northeast. Under winterwinds, slicks are most likely to drift to the west. Neither of these major drift axes is towards landfall(APASA, 2005).

In April 2011, additional quantitative hydrocarbon spill risk modelling was conducted by APASA for the‘worst case’ scenarios perceived for the Jansz-Io drilling operations. The modelling used a three

dimensional spill trajectory and weathering model (SIMAP) which is designed to simulate the transport,spreading and weathering of specific hydrocarbons under specific meteorological and oceanographicconditions. Two separate scenarios were modelled:

1. An 80,000 L spill of marine diesel, over 2 hours, onto the sea surface, representative of arefuelling incident;

2. A 250,000 L spill of marine diesel, over 2 hours, onto the sea surface, representative of thelargest possible storage tank rupture (largest tank in this drilling campaign);

These spill scenarios involved the release of hydrocarbon or diesel onto the water surface, formingsurface slicks that immediately become subject to spreading and atmospheric weathering. These surfacespill scenarios can be compared to the 2005 modelling that was conducted. For simulations of the 80,000L and 250,000 L diesel spills indicated very low probabilities (< 1%) of surface or entrained diesel > 0.15g/m2 arriving at any adjacent shorelines during any seasons.

3.2 Subsea Blowout

The modelling conducted in 2011 also included a third scenario:

An uncontrolled subsea blowout, persisting for 11 weeks, releasing a mixture of gas andcondensate, with the condensate discharge rate at 3,515 bbl/day (558,885 L/d). This equates toa total discharge of condensate over the 11 weeks of 270,655 bbl (43,034,145 L).

Subsea blowouts result in the break-up of oil into droplets, which remain entrained in the water columnuntil they surface. If and when droplets reach the surface is strongly dependent on the size distribution ofthe oil droplets (which affects their surface to volume ratio) and their density relative to the density of thewater column at vertical layers towards the surface.

The modelling indicated that the discharge would generate small droplets, with a size range ofapproximately 10 to 50μm which would have slow surfacing rates with the potential for a high percentage

(>90%) being trapped in the water column on reaching uniform density layers. Sensitivity testing on thesepredictions indicated that droplet sizes one order of magnitude (i.e. 10 x) larger would result in asignificantly faster surfacing time and a much reduced proportion (


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in the water column. Under these circumstances, a small proportion of the released oil would reach thesurface and result in isolated patches of relatively thin sheen.

Sensitivity testing for the size of the droplets indicated that droplets one order of magnitude larger wouldresult in a significant increase in the surfacing rate, and in turn, the proportion that will evaporate from thesurface. Additionally, marked variation in the prevailing drift current and wind conditions would beexpected over the 11 week duration of the release, increasing the spread of condensate during any singleevent.

Based on these conditions, stochastic simulation of the 11 week subsea blowout indicated lowprobabilities (< 1%) of surface condensate > 0.15 g/m² arriving at any of the surrounding shorelinesduring any season.

Entrained condensate does, however, have the potential to drift long distances with the offshore driftcurrents, with the highest probability of affecting waters close to shorelines immediately to the south-westin summer, autumn and winter.

The modelled estimates of entrained oil drifting towards the shoreline vary with the season and with thethreshold concentration levels used. At conservative concentrations of >10ppb (at least short-term 1 hourminimum) and in the season where drift currents are most likely to migrate the entrained oil to shore(Autumn) the sections of coastline around the North West Cape are indicated to have a moderately highprobability (up to 50%) of being affected. In the same season but using a higher threshold level of>200ppb, the probability drops to 10-20%. During the spring when migration to shore is least likely the

probabilities for reaching these shorelines are 2% for the >10ppb threshold and 200ppbthreshold.

The minimum period of time for the entrained oil to reach the shoreline in autumn (the mostly likelyseason for migration to shore) at any concentration (even less than 10ppb) is estimated at 74 days. Thisis indicative of the response time that would be available for shoreline protection measures to be put inplace

The thresholds for contact used in this study are indicative only and do not imply impact will occur.Definitive thresholds for impact would need to be based on tests of the sensitivity of organisms occupyingthe adjacent habitats with the specific condensate mixture, after weathering under realistic conditions.

One implication of the relatively small size of condensate droplets that are indicated by this study is thatthe dissolution of soluble compounds from the condensate should be relatively rapid, with the highestdissolution rates occurring initially, associated with the turbulent plume (French 2000). The more volatileand toxic, aromatic compounds would undergo dissolution leaving the remaining volumes of entrained oil

to be composed of, less volatile, longer carbon chain alkanes (Neff et al. 2000). In addition, the relativelylong durations that were indicated for oil to drift onto shorelines (75 days or more) from the blowoutscenario indicates that some level of bio-degradation would occur, which would also target the morevolatile, more toxic shorter-chained hydrocarbons (ASA, 2011). The level of biodegradation would alsodepend on the composition of the oil where non persistent oils (such as condensate) will degrade at amuch faster rate than persistent oils. The impact is that the remaining entrained oil is less toxic and lessbiologically available if it reaches the shoreline (Camilli et al. 2010)

The modelling also indicated that the condensate, which has a low viscosity, would tend to spread rapidlyat the surface. This implies that entrained oil that surfaces at a long distance from the discharge sourcewould tend to present as thin patches of sheen. The low residual (i.e. non evaporative) component in thefresh oil (0.5%) indicates that this oil sheen should also evaporate rapidly (within hours) when eventuallyexposed to the atmosphere, so that significant accumulation on shorelines is unlikely, if the sheens dodrift onto a shoreline.


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4. RESPONSE TEAMS AND PREPAREDNESS

4.1 Response Prior ities

ExxonMobil will consider the response priorities as defined in the WestPlan-MOP and NATPLAN, which

are: Human safety

Habitat and cultural resources

Rare and/or endangered species

Commercial resources

Recreational and amenity areas

Restoration of the environment, as near as practicable, to pre-spill conditions

4.2 Response Team Structure and Responsibili ties

4.2.1 Company Response Teams Roles and Responsibi lities

ExxonMobil has the responsibility for assuming the role of the combat agency should a spill occurs during

the Jansz-Io Drilling campaign. The emergency management structure for the Jansz-Io Drilling isdescribed within the Jansz-Io Emergency Response Plan [ExxonMobil 2011(b)]. As TransoceanDeepwater Frontier MODU will be conducting the drilling activities, the Jansz-Io ERP necessarilydescribes the combined ExxonMobil and Transocean resources for responding to emergencies, includingoil spills. Chevron, as operator of the Gorgon Project on behalf of the Gorgon Joint Venture Partners isalso a stakeholder in the Jansz-Io Drilling activities and will assist in response efforts if required asdescribed in the Jansz-Io ERP. In summary the Emergency Response framework for the Jansz-Io drillingcampaign is shown in Figure 4.1.

The underlining strategies of the framework for all emergencies, including safety environmental andtechnical emergencies are:

All emergencies on or around the DWF will be under the control of the Transocean VesselMaster per the processes described in the DWF Safety Case, the Transocean DWF ERMand the Jansz-Io ERP.

ExxonMobil Australia Drill Team (Melbourne Based) provides well site and operationalsupport for the MODU

Where additional resources, beyond the capability of the DWF, are required to manage theincident ExxonMobil will provide additional support by:

o Leveraging off existing ExxonMobil Australia response teams

o Engaging as needed Chevron's emergency response organisation and capabilities basedon staged engagement and tied to need and potential impact to the Gorgon Project

The ExxonMobil production affiliate based in Melbourne forms the Emergency Support Group (ESG) andtakes the lead in responding to the spill, has AMOSC trained oil spill responders which would be calledout as needed. Beyond the Australian based trained personnel ExxonMobil would call upon the otherresources it has available to it (AMOSC/ OSRL/ RRT etc) for trained oil spill responders.

Beyond the trained oil spill responders, ExxonMobil has available trained, rostered, designated

emergency response personnel which can be called out at any time and extensive resources to providesupport for an emergency response, including oil spill response (these resources support the Victorianand PNG ExxonMobil operated project/facilities). Resources would be mobilised from other affiliates asneeded.

As Gorgon Operator, Chevron would also be called upon to provide assistance.


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Figure 4.1 Jansz-Io Emergency Response Framework


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The primary roles of each emergency management team described in Figure 4.1 are summarised in thetables below.

Table 4.1: Emergency Response Teams and Roles

Organisation Abbreviation Definition / Role in an Emergency

Transocean Deepwater

FrontierEmergency Squad

DWF ES Transocean is the Operator of the Deepwater Frontier (the

“Facility” per the OPGGSA). Has the primary responsibilityto respond to all emergencies on or involving the facility.Retains control of all activities on the DWF at all times,including all emergencies. Comprised of DWF crew trainedin emergency response

Transocean EmergencyResponse Team

TO ERT Activated when an incident occurs on the DeepwaterFrontier.

Comprised of Transocean management team, including theRig Manager

Provides support and oversight to the DWF and makesrequests to ExxonMobil for additional support to managethe emergency on behalf of the DWF.

Provides information to the ExxonMobil DIMT or ESG for

the response

ExxonMobil Drilling IncidentManagement Team

DIMT Activated when an emergency occurs on the DeepwaterFrontier.

Emergency management team with the responsibility forsupporting a response and organising additional resourcesas requested by Transocean. Fulfills internalcommunication requirements for ExxonMobil DevelopmentCompany.

Provides technical engineering/ planning support to theresponse.

ExxonMobil EmergencySupport Group

ESG Activated by the DIMT when additional support is required

Emergency team with the overall responsibility for

managing the additional support required by TO to managethe response to a Level 2/3 incident. Provides emergencymanagement support including external communications tomedia and regulators. Functions include Public &Government Affairs, Legal and other support functions

Coordinates additional support through CVX on behalf ofTO and mobilizes additional EM resources from outside theregion.

Perth based sub group to the Melbourne based ESG willprovide local Gorgon Project knowledge and support to theESG

Chevron Barrow IslandSecurity Operations Centre

CVX BWISOC

Has authority to dispatch aircraft resources for medicalevacuations (helicopters and fixed wing aircraft) and SAR

Chevron Asset EmergencyManagement Team

CVX AEMT As Gorgon Operator’s (Chevron) principal emergencyresponse team, provides support to ExxonMobil (insupporting TO) via the ESG .

Has the ability to provide additional resources (from theGorgon Project) in support of the emergency response

Chevron CrisisManagement Team

CVX CMT Chevron’s emergency management team which providesstrategic support to the ExxonMobil ESG via the CVX AEMT

Comprised of Chevron personnel from senior managementtrained in emergency response


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4.3 Statutory responsibi lities

NATPLAN outlines the responsibilities for managing oil spills as described in Section 1.6.4. Theorganisation responsible depends on the location and source of the spill.

For each area of responsibility a statutory and a combat agency is nominated. These are defined asfollows:

Statutory Agency: the agency having the statutory responsibility for marine pollutionincidents in their area of jurisdiction

Combat Agency: the agency having operational responsibility in accordance with therelevant contingency plan to take action to respond to an oil or chemical spill in the marineenvironment

In some cases, the statutory and combat agencies will be the same agency.

Spills that may threaten state waters are generally managed by the relevant State or Territory (within 3NMof the Territorial Sea baseline).

The Department of Mines and Petroleum (DMP) is the nominated ‘Statutory Agency’ for Western Australia.

The WA Department of Transport (DoT), Marine Safety, is the Hazard Management Agency (HMA) formarine oil pollution emergencies and is thereby responsible for coordinating the State administration andoperation of the WestPlan-MOP in consultation with the State Emergency Management Committee. DoTwill appoint an Incident Controller to manage (in terms of planning, leading, organising and controlling)response and recovery operations to oil spills that occur in all Western Australian waters with theexception of Port Authority waters. Port Authorities have statutory responsibility to respond to oil spillswithin port waters and will appoint the Incident Controller accordingly. The Dampier Port Authority is theRegional First Response Agency for the Pilbara West district.

The WA State Response Team (SRT) is comprised of officers from a variety of agencies, organisationsand authorities. It is capable of rapid deployment to any spill site in support of the Incident Controller (IC).The NW Regional Response Team (RRT) has been developed in the Pilbara region of WA to complementand enhance the SRT arrangements.

Spills from Oil Industry activities

The Statutory Agency for oil spills from offshore petroleum operations is the relevant Designated Authority. For the Jansz-Io Drilling Campaign the Statutory Agency will be the Department of Mines andPetroleum (DMP).

Operators of offshore exploration and production activities are responsible for responding to spills fromtheir facilities and pipelines. Therefore, for the Jansz-Io Drilling Campaign, ExxonMobil will be theCombat Agency and will call on additional support from the Australian Maritime Safety Authority (AMSA)as required. The Combat Agency is required to undertake preventive and cleanup action as soon aspossible. The Statutory Agency, usually through a State Marine Pollution Committee (SMPC), will providemanagement, operational, technical and environmental advice and support to the Combat Agency asrequired. This may include support for the management of the response. The Combat Agency mayrequest another agency to act on its behalf.

Table 4.2: Statutory Agencies

Spill Source Location Statutory Agency

Offshore petroleum operations /MODU/ Drill Ship

Commonwealth waters DMP

Support Vessels Commonwealth waters AMSA

State waters DMP

Onshore supply base Port of Dampier DMP


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Table 4.3: Nominated Combat Agency’s

Location Spill SourceCombat Agency

Tier 1 Tier 2/3

Commonwealth waters MODU/ Drill Ship ExxonMobil ExxonMobil (1)

Vessel Vessel Owner AMSA

State waters MODU/ Drill Ship ExxonMobil ExxonMobil

Vessels Vessel Owner DoT

Port of Dampier Designated Port Company2 Port Authority

(1) ExxonMobil may request AMSA to take over Combat Agency role as required(2) Company responsible for the spill or company operating the facility at which spill occurs

4.3.1 Tiered Response

Marine pollution response is based on a graduated scale of response whereby the amount of resourcesmobilised for a response and the agency in control will vary according to the scale and location of theincident. The levels, or response Tiers, are defined according to:

The amount and source of resources deployed The levels of support and higher level management activated.

The amount and type of oil

The location of the spill and likely impact/consequences

The tiered response strategy is discussed further in Section 6.3.

ExxonMobil may hand over the responsibility of a marine pollution incident to the HMA IMT when:

All oil spill resources are being utilized and outside support is required

There is an original emergency that has utilized all ESG personnel such as a major fire/explosion and there is a secondary oil spill that requires management

There is unprecedented media coverage for a minor incident

There is an impact to marine wildlife, sea birds or mangrove communities that require

protecting before a shoreline impact There is a major marine transport emergency (collision or grounding) where there is a

potential for a major marine oil impact.

When a handover of control occurs:

The agency responsible for marine oil spills (AMSA for Commonwealth Waters and DMP forState Waters) will activate the NATPLAN or WestPlan-MOP and an Incident ManagementTeam (IMT) and appoint an Incident Controller (IC) to lead the IMT.

ExxonMobil has a pivotal liaising and support role to the IMT and Incident Controller:

The ExxonMobil PIC will liaise and support the appointed Incident Controller and will appointappropriate ExxonMobil personnel to liaise and support other critical functions through thePlanning, Operations, and Logistics sections.

Personnel will maintain their roles and responsibilities until relieved of their duties and/orassigned other tasks.

4.4 The Oil Spill Response Incident Control System (OSRICS)

The NATPLAN has a system which describes a series of functions required to be performed by a spillresponse team to enable the spill incident to be controlled. This is the Oil Spill Response Incident ControlSystem (OSRICS). Under the OSRICS system, for a large scale incident, the overall response strategywill be formulated by a nominated Marine Pollution Controller (MPC) and implemented by an IncidentController (IC) and section officers who form the Incident Management Team (IMT).


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The Marine Pollution Controller (MPC) must be capable of ministerial as well as senior government,industry and media liaison. The Incident Controller (IC) is responsible for the management andcoordination of response operations at the scene of a pollution incident to achieve the most cost effectiveand least environmentally damaging resolution to the problem.

The OSCRICS system defines four other main functions as follows:

Planning Planning undertakes the preparation of a Strategic and Incident Action Plans on behalf of the Incident Controller. Itis also responsible for the collation and interpretation of required scientific and environmental data and maintenanceof incident information services.

Operations

The Operations responsibility encompasses all operational activities related to the combat of the inciden

Documents

Gorgon Emp Mobil Australia Jansz Io Drilling Oil Spill Contingency Plan (1)