Gorgon Emp Gorgon Gas Development Drilling and Completion Program

  • Author
    afasf

  • View
    219

  • Download
    0

Embed Size (px)

Text of Gorgon Emp Gorgon Gas Development Drilling and Completion Program

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    1/160

    Chevron Australia Pty Ltd

    Document No: G1-NT-PLNX0001023 Revision: 0

    Revision Date: 9 June 2011 Copy No:

    IP Security: Public

    Environment PlanGorgon Gas Development Drilling andCompletion Program

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    2/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page v

    Printed Date: 7 July 2011 Uncontrolled when Printed

    Table of Contents

    Terminology, Definitions and Abbreviations .................................................................................................. 9

    Executive Summary ..................................................................................................................................... 18

    1.0

    Introduction ........................................................................................................................................ 19

    1.1

    Proponent ................................................................................................................................ 19

    1.2

    Project ..................................................................................................................................... 19

    1.3

    Location ................................................................................................................................... 19

    1.4

    Gorgon Gas Development Environmental Approvals ............................................................. 23

    1.5

    Purpose of this Plan ................................................................................................................ 24

    1.5.1

    Scope of this Environment Plan .............................................................................. 24

    1.5.2

    Requirements .......................................................................................................... 24

    1.5.3

    Hierarchy of Documentation .................................................................................... 26

    1.5.4

    Relevant Standards and Guidelines ........................................................................ 28

    1.5.5

    Stakeholder Consultation ........................................................................................ 29

    1.5.6

    Public Availability ..................................................................................................... 30

    2.0

    Drilling Activities ................................................................................................................................ 31

    2.1

    Overview ................................................................................................................................. 31

    2.2

    Well Design and Drilling Details .............................................................................................. 32

    2.2.1

    Design ...................................................................................................................... 32

    2.2.2

    Drilling Fluids and Chemical Additives .................................................................... 33

    2.2.3

    Drilling Fluids and Cuttings Handling and Disposal................................................. 34

    2.2.4

    Cleaning the SBM Holding Tanks ........................................................................... 35

    2.2.5

    Cementing Operations ............................................................................................. 35

    2.2.6

    Pre- and Post-drilling Seabed Surveys ................................................................... 35

    2.2.7

    Logging .................................................................................................................... 36

    2.2.8

    Well Testing and Clean-Up ...................................................................................... 36

    2.2.9 Well Suspension and Completion ........................................................................... 36

    2.2.10 Marine and Support Operations .............................................................................. 36

    2.2.11

    Time Frame ............................................................................................................. 37

    3.0

    Existing Marine Environment ............................................................................................................ 38

    3.1

    Physical Environment ............................................................................................................. 38

    3.1.1

    Bathymetry and Seabed Features ........................................................................... 38

    3.1.2

    Metocean Conditions ............................................................................................... 38

    3.2

    Marine Biological Environment ............................................................................................... 38

    3.2.1 Benthic Flora and Fauna ......................................................................................... 39

    3.2.2

    Macrofauna .............................................................................................................. 39

    3.3

    Social and Economic Environment ......................................................................................... 43

    3.3.1

    Petroleum Activities ................................................................................................. 43

    3.3.2

    Fisheries .................................................................................................................. 43

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    3/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page vi Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    3.3.3

    Shipping .................................................................................................................. 44

    3.3.4

    Recreational and Tourism Activities ....................................................................... 45

    3.3.5

    Marine Protected Areas .......................................................................................... 45

    3.3.6

    Shipwrecks.............................................................................................................. 45

    3.3.7

    Defence Practice Areas .......................................................................................... 45

    3.3.8

    Cultural Heritage ..................................................................................................... 45

    3.3.9

    Particular Issues or Sensitivities ............................................................................. 45

    4.0

    Risk Assessment .............................................................................................................................. 46

    4.1

    Overview ................................................................................................................................ 46

    4.2 Methodology ........................................................................................................................... 46

    4.3 Key Outcomes ........................................................................................................................ 61

    4.3.1 Routine and Operational Discharges ...................................................................... 61

    4.3.2

    Noise ....................................................................................................................... 66

    4.3.3

    Positioning and Presence of the Rig ...................................................................... 67

    4.3.4

    Quarantine .............................................................................................................. 67

    4.3.5

    Contingency Plan and Management of Unplanned Operations ............................. 68

    5.0

    Objectives, Performance Standards and Relevant Documentation ................................................. 72

    5.1 Overview ................................................................................................................................ 72

    5.2

    Objectives ............................................................................................................................... 72

    5.3

    Performance Standards ......................................................................................................... 72

    5.3.1

    Discharge of Drilling Fluid and Cuttings ................................................................. 72

    5.3.2

    Underwater Noise ................................................................................................... 73

    5.3.3

    Oil/Chemical Spill .................................................................................................... 73

    5.3.4

    Fuel (Diesel Spill) .................................................................................................... 73

    5.3.5

    Loss of Well Control ................................................................................................ 73

    5.3.6

    Quarantine .............................................................................................................. 73

    5.3.7 Discharge of Domestic Wastes............................................................................... 73

    5.4 Relevant Documentation ........................................................................................................ 73

    6.0

    Implementation ................................................................................................................................. 78

    6.1 Environmental Policy .............................................................................................................. 78

    6.2 Environmental Management Documentation ......................................................................... 78

    6.2.1 Overview ................................................................................................................. 78

    6.2.2 Chevron ABU OE Documentation .......................................................................... 78

    6.2.3 Gorgon Gas Development and Jansz Feed Gas Pipeline Documentation ............ 79

    6.2.4 Project-specific Documentation .............................................................................. 79

    6.2.5 Project-specific Plans and Procedures ................................................................... 80

    6.3

    Environmental Management Measures ................................................................................. 80

    6.3.1 Rig and Vessel Wastes, Discharges and Emissions .............................................. 80

    6.3.2 Vertical Seismic Profiling ........................................................................................ 81

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    4/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page vii

    Printed Date: 7 July 2011 Uncontrolled when Printed

    6.3.3

    Air Emissions ........................................................................................................... 82

    6.3.4

    Quarantine and Ballast Water ................................................................................. 83

    6.3.5

    Onboard Storage and Handling of Chemicals ......................................................... 83

    6.3.6

    Interaction with Other Users of the Area ................................................................. 83

    6.3.7

    Resupply Operations ............................................................................................... 84

    6.3.8

    Well Control ............................................................................................................. 85

    6.3.9

    Emergencies and Accidental Discharges ................................................................ 86

    6.4

    Training and Inductions ........................................................................................................... 86

    6.5

    Responsibilities ....................................................................................................................... 87

    6.5.1 Chain of Command .................................................................................................. 87

    6.5.2 Roles and Responsibilities ...................................................................................... 87

    6.6 Maintenance of Emergency Response and Marine Oil Pollution Plan ................................... 90

    7.0

    Auditing, Reporting and Review ........................................................................................................ 92

    7.1

    Auditing ................................................................................................................................... 92

    7.1.1

    Internal Auditing ....................................................................................................... 92

    7.1.2

    External Auditing ..................................................................................................... 92

    7.2

    Reporting ................................................................................................................................. 93

    7.2.1 Compliance Reporting ............................................................................................. 93

    7.2.2

    Environmental Performance Reporting ................................................................... 93

    7.2.3

    Routine Internal Reporting....................................................................................... 93

    7.2.4

    Monitoring and Audit ................................................................................................ 93

    7.2.5

    Incident Response and Reporting ........................................................................... 94

    7.2.6

    Reportable Incidents ................................................................................................ 95

    7.2.7

    Recordable Incidents ............................................................................................... 96

    7.2.8

    Record Keeping ....................................................................................................... 96

    7.3

    Review of this Plan ................................................................................................................. 97

    8.0 References ........................................................................................................................................ 98

    Appendix 1 Identification of Marine Matters of National Environmental Significance .............. 104

    Appendix 2

    EPBC Act Protected Matters Report ..................................................................... 105

    Appendix 3 Chevron Integrated Risk Prioritization Matrix ........................................................ 106

    Appendix 4 Oil Spill Operational Response Plan (OSORP) ..................................................... 108

    Appendix 5 Chevron Corporate Operational Excellence Policy 530 ........................................ 109

    Appendix 6 Computer Modelling of Noise Generated by VSP Source .................................... 110

    Appendix 7 Compliance Reporting Table ................................................................................. 111

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    5/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page viii Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    List of Tables

    Table 1-1 Requirements of this Plan ........................................................................................................ 24

    Table 2-1 Coordinates of the Development Wells .................................................................................... 31

    Table 2-2 Gorgon Development Well Design Details ............................................................................... 32

    Table 2-3 Gorgon Development Well Total Cuttings Volumes (per well) ................................................. 33

    Table 2-4 SBM Composition ..................................................................................................................... 34

    Table 3-1: EPBC Act Listed Threatened Species that may Occur within the Permit Area ...................... 39

    Table 4-1 Summary of Environmental Risks, Management and Mitigation Measures ............................ 48

    Table 4-2 NOVATEC Saraline 185V-based SBM Ecotoxicity Results for Western AustralianSpecies ................................................................................................................................ 61

    Table 4-3 Component Assay Data ........................................................................................................... 69

    Table 5-1 Objectives, Performance Standards and Relevant Documentation ......................................... 74

    Table 6-1 Well Controls and Mitigation/Recovery Measures ................................................................... 85

    Table 7-1 Incident Reporting Requirements ............................................................................................. 94

    List of Figures

    Figure 1-1 Location of the Gorgon Gas Field ........................................................................................... 20

    Figure 1-2 Proposed Well and Manifold Locations ................................................................................... 21

    Figure 1-3 Gorgon Development Manifold Locations: Associated Environmental and Socio-economic Sensitive Areas ................................................................................................... 22

    Figure 1-4 Hierarchy of Gorgon Gas Development Environmental Documentation ................................ 27

    Figure 1-5 Deliverable Development, Review and Approval Flow Chart ................................................. 30

    Figure 2-1 Bathymetry at Manifold and Well Locations ............................................................................ 32

    Figure 6-1 Gorgon Gas Development Drilling Organisation Chart ........................................................... 91

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    6/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 9

    Printed Date: 7 July 2011 Uncontrolled when Printed

    Terminology, Definitions and Abbreviations

    Terms, definitions and abbreviations used in this document are listed below. These align withthe terms, definitions and abbreviations defined in Schedule 2 of the Western Australian GorgonGas Development Ministerial Implementation Statement No. 800 (Statement No. 800) and theCommonwealth Gorgon Gas Development Ministerial Approvals (EPBC Reference: 2003/1294

    and 2008/4178).

    C Degrees Celsius

    3D Three-dimensional

    ABS American Bureau of Shipping

    ABU Australasia Business Unit

    ADIOS Automated Data Inquiry for Oil Spills

    AFMA Australian Fisheries Management Authority

    AFZ Australian Fishing Zone

    AHTSV Anchor Handling, Tug and Supply Vessel

    ALARP As Low As Reasonably Practicable

    Defined as a level of risk that is not intolerable, and cannot be reducedfurther without the expenditure of costs that are grossly disproportionate tothe benefit gained.

    AMOSC Australian Marine Oil Spill Centre

    AMSA Australian Maritime Safety Authority

    Annulus The space between two concentric objects, such as between the wellboreand casing or between casing and tubing, where fluid can flow.

    APASA Asia-Pacific Applied Science Associates

    APPEA Australian Petroleum Production and Exploration Association

    AQIS Australian Quarantine and Inspection Service

    ARI Assessment on Referral Information (for the proposed Jansz Feed GasPipeline dated September 2007) as amended or supplemented from timeto time.

    ARPA Automated Radar Plotting Aid

    AS Australian Standard

    AusRep Australian Ship Reporting

    AusSAR Australian Search and Rescue

    Ballast water Any water and associated sediment used to trim and stabilise a vessel.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    7/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 10 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Bathymetric Relating to measurements of the depths of oceans or lakes.

    bbl Barrel

    Benthic Living upon or in the sea floor.

    Bentonite clay Clay formed from volcanic ash which can absorb large amounts of waterand expands to many times its normal volume.

    Biocide Any substance that can destroy living organisms.

    Biota All the plant and animal life of a particular region.

    Bioturbation The displacement and mixing of sediment particles by benthic fauna(animals) or flora (plants).

    BOP Blow Out Preventer

    BP Boiling Point

    Bund An area of containment, such as a dam, wall, or other artificialembankment.

    CaCl2 Calcium Chloride

    CAMBA China-Australia Migratory Bird Agreement

    Carbon Dioxide(CO2) Injection

    System

    The mechanical components required to be constructed to enable theinjection of reservoir carbon dioxide, including but not limited to

    compressors, pipelines and wells.

    CCSBT Commission for the Conservation of Southern Bluefin Tuna

    CCTV Closed Circuit Television

    CEFAS Centre for Environment, Fisheries and Aquaculture Science

    Cetacean Various aquatic (mainly marine) mammals of the order Cetacea, (includingwhales, dolphins and porpoises) characterised by a nearly hairless body,front limbs modified into broad flippers and a flat notched tail.

    CGR Condensate/Gas Ratio

    CHARM Chemical Hazard Assessment and Risk Management

    CO2 Carbon Dioxide

    Coaming A raised rim or border around an opening, as in a ship's deck, designed tokeep out water.

    CommonwealthMarine Areas

    Zoned areas of waters of the sea, the seabed and the airspace above thewaters of the sea, defined under section 24 of the EPBC Act (Cth).

    cP Centipoise; a unit of dynamic viscosity equal to 1 millipascal second

    Cth Commonwealth of Australia

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    8/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 11

    Printed Date: 7 July 2011 Uncontrolled when Printed

    D&C Drilling and Completion

    dB Decibel; a unit to measure sound

    dB re 1 Pa Decibels relative to one micro pascal; the unit used to measure the

    intensity of an underwater sound

    Deadman A function to a safe mode that is automatically activated if all power andcontrols are lost to the equipment.

    DEC Western Australian Department of Environment and Conservation

    DEH Former Department of the Environment and Heritage (now SEWPaC)

    Demersal Living on the seabed or just above it.

    DEWHA Former Commonwealth Department of the Environment, Water, Heritage

    and the Arts (now SEWPaC)

    Diurnal Daily

    DMP Western Australian Department of Mines and Petroleum (formerly DoIR)

    DNV Det Norske Veritas; independent foundation that provides services formanaging risk

    DoIR Western Australian Department of Industry and Resources (now DMP)

    DP Dynamic Positioning; a computer controlled system to automatically

    maintain a vessel's position and heading by using her own propellers andthrusters

    DP Class 2 Dynamic positioning equipment Class 2 has redundancy so that no singlefault in an active system will cause the system to fail. Loss of positionshould not occur from a single fault of an active component or systemsuch as generators, thruster, switchboards, remote controlled valves etc.but may occur after failure of a static component such as cables, pipes,manual valves etc.

    DSM Drill Site Manager

    EC50 Concentration or dose yielding biological effects in 50% of test species.

    EIS/ERMP Environmental Impact Statement/Environmental Review and ManagementProgramme (for the Proposed Gorgon Gas Development datedSeptember 2005) as amended or supplemented from time to time.

    EMP Environmental Management Plan

    EP Environment Plan

    EP Act Western Australian Environmental Protection Act 1986

    EPA Western Australian Environmental Protection Authority

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    9/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 12 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    EPBC Act Commonwealth Environment Protection and Biodiversity Conservation Act1999

    EPBC Reference:2003/1294

    Commonwealth Ministerial Approval (for the Gorgon Gas Development) asamended or replaced from time to time

    EPBC Reference:2005/2184

    Commonwealth Ministerial Approval (for the Jansz Feed Gas Pipeline) asamended or replaced from time to time.

    EPBC Reference:2008/4178

    Commonwealth Ministerial Approval (for the Revised Gorgon GasDevelopment) as amended or replaced from time to time.

    EPCM Engineering, Procurement and Construction Management

    EPS Environmental Performance Standard

    ERP Emergency Response Plan

    Finfish A term used to distinguish fish with fins and gills, from shellfish, crayfish,jellyfish, etc.

    G&G Geology and Geophysics

    g/m2 Grams per square metre

    gal/100 bbl Gallons per 100 barrels

    GDA94 Geocentric Data of Australia

    GM General Manager

    Gorgon GasDevelopment

    The Gorgon Gas Development as approved under Statement No. 800 andEPBC Reference: 2003/1294 and 2008/4178 as amended or replacedfrom time to time.

    GU Global Upstream

    HAZID Hazard Identification

    HAZOP Hazard and Operability Study

    Helideck Helicopter platform

    Helifuel Helicopter fuel

    HES Health, Environment and Safety

    HPU Hydraulic power unit

    HSE Health, Safety and Environment

    HTB High Temperature Blend

    Hydrocarbons A large class of organic compounds composed of hydrogen and carbon.Crude oil, natural gas, and natural gas condensate are all mixtures ofvarious hydrocarbons.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    10/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 13

    Printed Date: 7 July 2011 Uncontrolled when Printed

    IMDG International Maritime Dangerous Goods

    IMO International Maritime Organization

    IMS Invasive Marine Species

    Infauna Benthic fauna (animals) living in the substrate and especially in a soft seabottom.

    IP Intellectual Property

    ISO International Organization for Standardization

    Isobath A line on a chart joining places of equal depth of water; a depth contour.

    JAMBA Japan-Australia Migratory Bird Agreement

    Jansz Feed GasPipeline

    The Jansz Feed Gas Pipeline as approved in Statement No. 769 andEPBC Reference: 2005/2184 as amended or replaced from time to time.

    kcal/h Kilocalories per hour

    kg/m3 Kilograms per cubic metre

    km Kilometre

    L Litres

    L/h Litres per hour

    LAO Linear Alpha Olefin

    lb Pound

    LC50 Concentration or dose found to be lethal in 50% of a group of test species.

    LMRP Lower Marine Riser Package

    LNG Liquefied Natural Gas

    LOEC Lowest Observed Effect Concentration

    LOT Leak Off Test

    m Metre

    m/s Metres per second

    m3 Cubic metres

    Macrofauna Animals whose shortest dimension is greater than or equal to 0.5 mm andthat can be seen without the aid of magnification; includes polychaetes,snails and amphipods.

    Macrophytes A large aquatic plant, visible to the unaided eye, that grows in or nearwater and is either emergent, submergent, or floating (e.g. kelp).

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    11/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 14 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Marine Facilities In relation to Statement No. 800 and EPBC Reference: 2003/1294 and2008/4178, the Marine facilities are the:

    Materials Offloading Facility (MOF)

    LNG Jetty

    Dredge Spoil Disposal Ground

    Offshore Feed Gas Pipeline System and the marine component of theshore crossing

    Domestic Gas Pipeline.

    Marine Turtles Sea turtles of families Cheloniidae (Green, Flatback, Hawksbill,Loggerhead and Olive Ridley) and Dermochelyidae (Leatherback).

    MARPOL The International Convention for the Prevention of Pollution From Ships,1973 as modified by the Protocol of 1978.

    Also known as MARPOL 73/78.

    (MARPOL is short for marine pollution)

    Metocean Meteorological and oceanographic conditions.

    MFO Marine Fauna Observer

    mg/L Milligrams per litre

    Migratory Species Species listed as migratory under section 209 of the EPBC Act (Cth).

    mm Millimetre

    MMO Marine Mammal Observer

    MMscf/day Million standard cubic feet per day. 1 MMscf/day = 1180 Sm3/h (Standardcubic metres per hour).

    MOF Materials Offloading Facility

    MOPP Marine Oil Pollution Plan

    MSDS Material Safety Data Sheet. A widely used system for cataloguing

    information on substances, such as chemicals, chemical compounds, andchemical mixtures. MSDS information may include instructions for thesafe use and potential hazards associated with a particular material orproduct.

    MTPA Million Tonnes Per Annum

    N/A Not Applicable

    Nearshore Close to shore; or within 3 nautical miles of Barrow Island.

    Neritic The neritic zone, also called the sublittoral zone, is the part of the ocean

    extending from the low tide mark to the edge of the continental shelf, witha relatively shallow depth of

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    12/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 15

    Printed Date: 7 July 2011 Uncontrolled when Printed

    NES [Matters of] National Environmental Significance, as defined in Part 3,Division 1 of the EPBC Act (Cth).

    NGER Act Commonwealth National Greenhouse and Energy Reporting Act 2007

    nm Nautical Miles

    NOEC No Observable Effect Concentration

    NPI National Pollution Inventory

    NZS New Zealand Standard

    OE Operational Excellence

    OECD Organisation for Economic Co-operation and Development

    OEMS Operational Excellence Management System

    OIM Offshore Installation Manager

    OPGGS (E)Regulations

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

    OPGGS Act Commonwealth Offshore Petroleum and Greenhouse Gas Storage Act2006

    OSORP Oil Spill Operational Response Plan

    Pelagic Living in the open sea rather than in coastal or inland waters.

    PER Public Environmental Review

    PerformanceStandards

    Are matters which are developed for assessing performance, notcompliance, and are quantitative targets or where that is demonstrated tobe not practicable, qualitative targets, against which progress towardsachievement of the objectives of conditions can be measured.

    PGPA Policy, Government and Public Affairs

    Photic Zone The depth of the water in a lake or ocean that is exposed to sufficient

    sunlight for photosynthesis to occur. The depth of the photic zone can begreatly affected by turbidity.

    POB Persons on Board

    ppm Parts per million

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    13/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 16 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Practicable Practicable means reasonably practicable having regard to, among otherthings, local conditions and circumstances (including costs) and to thecurrent state of technical knowledge.

    For the purposes of the conditions of EPBC Reference: 2003/1294 and2008/4178 that include the term practicable, when considering whether

    the draft plan meets the requirements of these conditions, theCommonwealth Minister will determine what is practicable having regardto local conditions and circumstances including but not limited topersonnel safety, weather or geographical conditions, costs,environmental benefit and the current state of scientific and technicalknowledge.

    psi Pounds per square inch

    QC Quality Control

    RAAF Royal Australian Air Force

    ROC Retention on Cuttings

    ROKAMBA Republic of Korea-Australia Migratory Bird Agreement

    ROV Remotely Operated Vehicle

    SAFE Safety Analysis and Functional Evaluation

    SBM Synthetic-based Mud

    SBT Southern Bluefin Tuna

    SCSSV Surface-controlled Subsurface Safety Valve

    SEWPaC Commonwealth Department of Sustainability, Environment, Water,Population and Communities (formerly DEWHA)

    Significant Impact An impact on a Matter of National Environmental Significance, relevant toEPBC Reference: 2003/1294, 2005/2185 and 2008/4178 that is important,notable or of consequence having regard to its context or intensity.

    Slug Pit Tank for storing drilling fluid

    SOPEP Shipboard Oil Pollution Emergency Plan

    Statement No. 748 Western Australian Ministerial Implementation Statement No. 748 (for theGorgon Gas Development) as amended from time to time [superseded byStatement No. 800].

    Statement No. 769 Western Australian Ministerial Implementation Statement No. 769 (for theJansz Feed Gas Pipeline) as amended from time to time.

    Statement No. 800 Western Australian Ministerial Implementation Statement No. 800 (for theGorgon Gas Development) as amended from time to time.

    Substrate The surface a plant or animal lives upon. The substrate can include bioticor abiotic materials. For example, encrusting algae that lives on a rockcan be substrate for another animal that lives above the algae on the rock.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    14/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 17

    Printed Date: 7 July 2011 Uncontrolled when Printed

    TAPL Texaco Australia Pty. Ltd.

    TDF Terrestrial Disturbance Footprint

    Threatened

    Species

    Species listed as extinct, extinct in the wild, critically endangered,

    endangered, vulnerable or conservation dependent under section 178 ofthe EPBC Act (Cth).

    Turbidity The cloudiness or haziness of a fluid caused by individual particles(suspended solids) that are generally invisible to the naked eye, similar tosmoke in air. The measurement of turbidity is a key test of water quality.

    UK CAA United Kingdom Civil Aviation Authority

    VMS Vessel Management System

    VP Vice President

    VSP Vertical Seismic Profile

    WA Western Australia

    WAFIC Western Australian Fishing Industry Council

    WAPET West Australian Petroleum Pty Ltd.

    WAPET Landing Proper name referring to the site of the barge landing existing on the eastcoast of Barrow Island prior to the date of Statement No. 800.

    WBM Water-based Mud

    WMP Waste Management Plan

    WOMP Well Operations Management Plan

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    15/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 18 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Executive Summary

    This document provides a Plan (Environment Plan (EP)) for managing the potential impacts of aproposed drilling program in Commonwealth waters of the North West Shelf, which is scheduledto commence mid 2011 and is anticipated to be completed by mid to late 2013. This EP fulfilsthe relevant requirements of Conditions 16A of the Variation Decision for the Gorgon Gas

    Development (EPBC Reference: 2003/1294), Condition 3.2 of EPBC Reference 2003/1294 and2008/4178, as well as those of the Commonwealth Offshore Petroleum and Greenhouse GasStorage Act 2006(OPGGS Act).

    Eight Gorgon Gas Development wells will be drilled within Exploration Permit WA-37-L byChevron Australia Pty Ltd (Chevron Australia) using the Atwood Ospreysemi-submersible rig.Environmental management for the drilling and completions program will be conducted inaccordance with this EP and a specific Waste Management Plan. This EP describes thefollowing:

    the area of operations, the proposed drilling activities, and the expected time frame

    the existing natural, social and economic environments of the region, including issues and

    sensitivities particular to the drilling activities

    the possible risks to the environment from both planned (normal) and unplanned (abnormal)operations

    Chevrons Environmental Policy and the environmental performance objectives derived fromthe Policy

    the standards and criteria that will be used to measure environmental performance

    the Implementation Strategy, including key roles and responsibilities, that will be applied toachieve the programs environmental performance goals

    a system for documenting, monitoring, and reviewing the success of the ImplementationStrategy, to facilitate improvement of environmental performance.

    Assessment of the environmental risks and effects of the drilling program indicates that thelikely impacts are temporary and/or localised, and are limited to:

    physical disturbance of the seabed and benthic communities from the anchoring of the rig,discharge of the cuttings, and drilling of wells

    reduction in water quality from waste discharges (including drilling fluid, cuttings, greywater,and sewage wastes)

    disturbance to marine macrofauna and benthic communities from the presence, artificiallighting, and/or movements of the rig, support vessels, and helicopters

    disturbance to marine fauna species from noise and vibration emissions from the rig andvessels

    reduction in air quality from atmospheric emissions resulting from the flaring of hydrocarbonsand engine emissions.

    Due to the remote location of the drilling program and the comprehensive management that willbe implemented, risks to the environment are all considered to fall within the low or lowmediumcategory.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    16/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 19

    Printed Date: 7 July 2011 Uncontrolled when Printed

    1.0 Introduction

    1.1 Proponent

    Chevron Australia Pty Ltd (Chevron Australia) is the proponent and the person taking the actionfor the Gorgon Gas Development on behalf of the following companies (collectively known as

    the Gorgon Joint Venturers):

    Chevron Australia Pty Ltd

    Chevron (TAPL) Pty Ltd

    Shell Development (Australia) Proprietary Limited

    Mobil Australia Resources Company Pty Limited

    Osaka Gas Gorgon Pty Ltd

    Tokyo Gas Gorgon Pty Ltd

    Chubu Electric Power Gorgon Pty Ltd

    pursuant to Statement No. 800 and EPBC Reference: 2003/1294 and 2008/4178.

    1.2 Project

    Chevron Australia proposes to develop the gas reserves of the Greater Gorgon Area (Figure1-1).

    Subsea gathering systems and subsea pipelines will be installed to deliver feed gas from theGorgon and JanszIo gas fields to the west coast of Barrow Island. The feed gas pipelinesystem will be buried as it traverses from the west coast to the east coast of the Island, wherethe system will tie in to the Gas Treatment Plant located at Town Point. The Gas TreatmentPlant will comprise three Liquefied Natural Gas (LNG) trains capable of producing a nominalcapacity of five Million Tonnes Per Annum (MTPA) per train. The Gas Treatment Plant will alsoproduce condensate and domestic gas. Carbon dioxide (CO2), which occurs naturally in thefeed gas, will be separated during the production process. As part of the Gorgon GasDevelopment, Chevron Australia will inject the separated CO2 into deep formations belowBarrow Island. The LNG and condensate will be loaded from a dedicated jetty offshore fromTown Point and then transported by dedicated carriers to international markets. Gas fordomestic use will be exported by a pipeline from Town Point to the domestic gas collection anddistribution network on the mainland.

    Proposed drilling activities in support of the Gorgon Gas Development will comprise eightdevelopment wells to be drilled within Permit Area WA-37-L. Drilling operations are scheduled

    to commence in June 2011 and will extend until all the Gorgon wells are drilled and completed,which is anticipated to be by the end of 2013.

    1.3 Location

    The Gorgon gas field is located in Production Licence WA-37-L, in Commonwealth marinewaters of the North West Shelf, off Western Australia (Figure 1-1 andFigure 1-2). ProductionLicence WA-37-L is located approximately 130 km off the north-west coast of Western Australia,and 65 km north-west of Barrow Island. Barrow Island is located off the Pilbara coast 85 kmnorth-north-east of the town of Onslow and 140 km west of Karratha. The Island isapproximately 25 km long and 10 km wide and covers 23 567 ha. It is the largest of a group ofislands, including the Montebello and Lowendal Islands (Figure 1-3).

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    17/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 20 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Figure 1-1 Location of the Gorgon Gas Field

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    18/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 21

    Printed Date: 7 July 2011 Uncontrolled when Printed

    Figure 1-2 Proposed Well and Manifold Locations

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    19/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 22 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Figure 1-3 Gorgon Development Manifold Locations: Associated Environmental andSocio-economic Sensitive Areas

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    20/160

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    21/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 24 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    (Statement No. 769) and the Commonwealth Minister for the Environment and WaterResources on 22 March 2006 (EPBC Reference: 2005/2184).

    This Plan covers the Gorgon Gas Development as approved under EPBC Reference:2003/1294 and 2008/4178.

    1.5 Purpose of this Plan

    1.5.1 Scope of this Environment Plan

    This Plan has been prepared to ensure that drilling activities for the Gorgon Gas Development,as described in Section2.0,are conducted in a manner that protects environmental values andreduces impacts to the environment to as low as reasonably practicable (ALARP).

    1.5.2 Requirements

    For the proposed drilling program, this Plan satisfies the relevant requirements of Condition 16Aof the Variation Decision for the Gorgon Gas Development (EPBC Reference: 2003/1294) for

    the Management of Offshore Impacts, which is quoted below:Prior to commencement of construction of offshore facilities in Commonwealth waters, theperson taking the action must submit for the Ministers approval a plan (or plans) formanaging the impacts of the action....

    Offshore construction may not commence in Commonwealth marine areas until the plan isapproved.

    This Plan also addresses the relevant requirements of Condition 3.2 of EPBC Reference:2003/1294 and 2008/4178. Table 1-1 summarises the specific requirements of the relevantconditions of EPBC Reference: 2003/1294 and where they are addressed in this Plan.

    This Plan is also required under the Commonwealth Offshore Petroleum Gas and Greenhouse

    Gas Storage Act 2006 (OPPGS Act)and associatedOffshore Petroleum Gas and GreenhouseGas Storage (Environment) Regulations 2009(OPGGS (E) Regulations), to be approved by theDesignated Authoritythe Western Australian Department of Mines and Petroleum (DMP).

    This Plan is being submitted for approval only for the scope of works outlined in Section2.0. Inaccordance with Condition 16A of EPBC Reference: 2003/1294, approval of other plans tomanage the impacts of additional offshore construction activities will be obtained beforeconstruction commences for those specific activities.

    The process for development, review and approval of this Plan is shown inFigure 1-5.

    Table 1-1 Requirements of this Plan

    MinisterialDocument

    ConditionNo.

    Requirement Section Referencein this Plan

    EPBC Ref:2003/1294and2008/4178

    3.2.1 Provide a description of the EPBC listed speciesand their habitat likely to be impacted by thecomponents of the action which are the subject ofthe plan.

    Section3.2,Appendix1,andAppendix 2

    EPBC Ref:2003/1294and2008/4178

    3.2.2 Provide an assessment of the risk to these speciesfrom the components of the action the subject ofthat plan, relevant to the plan.

    Section4.0 andAppendix 3

    EPBC Ref:2003/1294and

    3.2.3 Provide details of the management measuresproposed in relation to these species if it is arequirement of the condition requiring that plan.

    Section6.3.2 andAppendix 6

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    22/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 25

    Printed Date: 7 July 2011 Uncontrolled when Printed

    MinisterialDocument

    ConditionNo.

    Requirement Section Referencein this Plan

    2008/4178

    EPBC Ref:2003/1294

    16A.1.i Design and construction of facilities to allow for thecomplete removal of all structures and components(except flowlines) above the sea floor

    Section2.0

    EPBC Ref:2003/1294

    16A.1.ii Sea floor surveys around proposed flowline pathsand well sites to identify sensitive marineecosystems such as reefs, sponge beds and seagrasses and historic shipwrecks

    Sections2.2.6,3.1.1,and4.3.3.1

    EPBC Ref:2003/1294

    16A.1.iii Selection of flowline paths and well sites to avoidimpacts on sensitive marine ecosystems andhistoric shipwrecks as referred to in 16A.1ii

    Sections2.2.6 and3.2.1

    EPBC Ref:2003/1294

    16A.1.iv Establish baseline information to inform a risk-based approach to environmental managementand monitoring of action-attributable impacts towater quality, benthic flora and fauna and keystonespecies from the installation and operation ofmarine facilities.

    Sections2.2.6 and3.2

    EPBC Ref:2003/1294

    16A.1.v A schedule of works Section2.0

    EPBC Ref:2003/1294

    16A.1.vi Managing the impacts on cetaceans, includinginteraction procedures for aircraft, supply andconstruction vessels that are consistent with part 8of the Environment Protection and BiodiversityConservation Regulations 2000

    Sections4.3.3,5.3.2,and6.3.2

    EPBC Ref:2003/1294

    16A.1.vii Cetaceans sightings reporting Sections 7.2.4 and7.2.6

    EPBC Ref:2003/1294

    16A.1.viii Hydrotest fluid type, handling and disposal Not ApplicableseeSection2.1

    EPBC Ref:2003/1294

    16A.1.ix Ballast water management for internationalconstruction vessels arriving in Australia inaccordance with Australian Quarantine andInspection Service Australian Ballast WaterManagement Requirements

    Sections4.3.4,5.3.6,6.3.4,and7.2.6.1

    EPBC Ref:2003/1294

    16A.1.x The use and disposal of drilling muds Sections2.2,4.3.1.1,6.3.1.1,and7.2.6.2

    EPBC Ref:2003/1294

    16A.1.xi The monitoring and disposal of produced formationwater, if it is planned to dispose of it to theCommonwealth marine environment

    Not ApplicableseeSection2.1

    EPBC Ref:2003/1294

    16A.1.xii A plan for contingencies and the management ofunplanned events such as oil or gas leaks or spills

    Sections4.3.5,5.3.3,5.3.4, 5.3.5,6.3.5,6.3.7,6.3.8,6.3.9,and

    Appendix 4

    Any matter specified in this Plan is relevant to the Gorgon Gas Development only if that matterrelates to the specific activities or facilities associated with that particular development.

    The sections in this Plan which are noted in the above table to meet the conditions of EPBCReference: 2003/1294 and 2008/4178 shall be read and interpreted as only requiringimplementation under EPBC Reference: 2003/1294 and 2008/4178 for managing the impacts ofthe Gorgon Gas Development on, or protecting, the EPBC Act matters listed inAppendix 1

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    23/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 26 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    1.5.3 Hierarchy of Documentation

    This Plan will be implemented for the Gorgon Gas Development via the Chevron AustralasiaBusiness Unit (ABU) Operational Excellence Management System (OEMS). The OEMS is thestandardised approach that applies across the ABU in order to continuously improve themanagement of safety, health, environment, reliability and efficiency to achieve world-class

    performance. Implementation of the OEMS enables the Chevron ABU to integrate itsOperational Excellence (OE) objectives, processes, procedures, values, and behaviours into thedaily operations of Chevron Australia personnel and contractors working under ChevronAustralias supervision. The OEMS is designed to be consistent with and, in some respects, gobeyond ISO 14001:2004 (Environmental Management SystemsRequirements with Guidancefor Use) (Standards Australia/Standards New Zealand 2004).

    Figure 1-4 provides an overview of the overall hierarchy of environmental managementdocumentation within which this Plan exists. Further details on environmental documentationfor the Gorgon Gas Development are provided in Section6.1 of this Plan.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    24/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 27

    Printed Date: 7 July 2011 Uncontrolled when Printed

    Figure 1-4 Hierarchy of Gorgon Gas Development Environmental Documentation

    Note: The above figure refers to all Plans required for Ministerial Statement No. 800. The Plans are only relevant to EPBC Reference: 2003/1294, if required for those Conditions ofthose approvals.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    25/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 28 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    1.5.4 Relevant Standards and Guidelines

    The following standards and guidelines, including applicable legal, environmental, and otherrequirements, have been taken into account in the development of this Plan:

    Code of Environmental Practice (Australian Petroleum Production and ExplorationAssociation [APPEA] 2008)

    Commonwealth Quarantine Act 1908

    Commonwealth Quarantine Regulations 2000

    CommonwealthAustralian Maritime Safety Authority Act 1990

    Commonwealth Environment Protection and Biodiversity Conservation Act 1999(EPBC Act)

    Commonwealth Environment Protection (Sea Dumping) Act 1981

    Commonwealth Historic Shipwrecks Act 1976

    CommonwealthNative Title Act 1993

    Commonwealth Offshore Petroleum and Greenhouse Gas Storage Act 2006(OPGGS Act)

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

    Commonwealth Protection of the Sea (Prevention of Pollution from Ships) Act 1983

    CommonwealthAustralian Heritage Commission Act 1975

    Commonwealth Department of Resources, Energy and Tourism Guidelines for thePreparation of an Environment Plan

    Western Australian Department of Industry and Resources (DoIR) Petroleum Guidelines

    Drilling Fluids Management (DoIR 2006)

    The principal international agreement governing petroleum operations in both State andCommonwealth waters is the United Nations Convention on the Law of the Sea 1982. Australiais also a signatory to a number of international conventions of relevance to the proposedproject:

    Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention)

    Convention on Wetlands of International Importance Especially as Waterfowl Habitat(RAMSAR)

    International Convention on Oil Pollution Preparedness, Response and Co-operation 1990

    United Nations Convention on the Law of the Sea 1982 (UNCLOS)

    United Nations Framework Convention on Climate Change

    International Convention for the Prevention of Pollution from Ships 1973, as modified by theProtocol of 1978 (MARPOL 73/78)

    Protocol to International Convention on the Prevention of Marine Pollution by Dumping ofWaste and Other Matter 1972 (London Dumping Convention).

    JapanAustralia Migratory Bird Agreement (JAMBA)

    ChinaAustralia Migratory Bird Agreement (CAMBA)

    Republic of KoreaAustralia Migratory Bird Agreement (ROKAMBA).

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    26/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 29

    Printed Date: 7 July 2011 Uncontrolled when Printed

    1.5.5 Stakeholder Consultation

    Consultation with stakeholders has been undertaken by Chevron Australia on a regular basisthroughout the development of environmental impact assessment management documentationfor the Gorgon Gas Development and Jansz Feed Gas Pipeline. This has includedengagement with the community, government departments, industry operators and contractors

    to Chevron Australia via planning workshops, risk assessments, meetings, teleconferences, andthe PER and EIS/ERMP formal approval processes.

    In December 2010, additional consultations specifically regarding the proposed drilling andcompletions program were undertaken. A detailed written description (letter) of the drillingprogram, including the water depths of the permit area, the distance of the permit area fromBarrow Island and North West Cape, the number of wells to be drilled and the specificcoordinates for each well location, was provided to each stakeholder. Attached to the letter wasa figure showing the permit areas, well locations, bathymetry, other oil and gas permit areas,and distances to land. This letter (with attached figure) was emailed to these stakeholders:

    Australian Fisheries Management Authority (AFMA)

    Australian Maritime Safety Authority (AMSA)

    Western Australian Department of Fisheries

    Commonwealth Department of Defence

    Commonwealth Fisheries Association

    Australian Southern Bluefin Tuna Industry Association

    A. Raptis and Sons

    JAMACLAN Marine Services

    Northern Fishing Companies Association

    TunaWest

    Recfishwest

    Western Australian Fishing Industry Council

    Western Australian Northern Trawl Owners Association

    Western Australian Seafoods.

    The key outcomes of this consultation were that:

    Low levels of commercial shipping traffic are expected near the permit area.

    Southern Bluefin Tuna spawning occurs north of the survey area between September andApril with a peak in December through to March, and the Leeuwin Current may entrainjuveniles through the permit area during operations.

    Fishing activity for the State fisheries is likely to be very low in the area of proposed drilling.

    The Australian Hydrographic Office (AHO) (response through the Department of Defence)requires information on whether the wells are left suspended, or plugged and abandoned oncompletion of the drilling.

    Chevron Australia will maintain communications with relevant agencies, fishery groups, and portauthorities to ensure that they are informed of any aspects of the drilling program that may

    affect other users of the area.The process for development, review and approval of this Plan is shown inFigure 1-5.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    27/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 30 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Figure 1-5 Deliverable Development, Review and Approval Flow Chart

    1.5.6 Public Availability

    This Plan will be made public as and when determined by the Minister under Condition 22 of

    EPBC Reference: 2003/1294 and 2008/4178.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    28/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 31

    Printed Date: 7 July 2011 Uncontrolled when Printed

    2.0 Drilling Activities

    2.1 Overview

    As part of the Gorgon Gas Development, Chevron Australia proposes to conduct drilling andwell testing activities within Production Licence WA-37-L for eight development wells,. All

    operations will be conducted in accordance with relevant Acts and Regulations to meet therequirements of the OPGGS Act. The wells will be drilled using the Atwood Oceanics PacificPty Ltd (Atwood)Atwood Ospreysemi-submersible rig.

    Proposed drilling activities in support of the Gorgon Gas Development will comprise eightdevelopment wells to be drilled within Permit Area WA-37-L. Drilling operations are scheduledto commence in June 2011 and will extend until all the Gorgon wells are drilled and completed,which is anticipated to be by the end of 2013.

    Table 2-1 Coordinates of the Development Wells

    Well Name Latitude (GDA94) Longitude (GDA94) Water Depth (m)

    GOR-1C 20 24 28.372 S 114 50 56.841 E 215

    GOR-1D 20 24 28.611 S 114 50 57.734 E 215

    GOR-1E 20 24 29.171 S 114 50 58.313 E 215

    GOR-1F 20 24 30.019 S 114 50 58.543 E 215

    GOR-2B 20 27 36.535 S 114 50 31.386 E 199

    GOR-2C 20 27 37.095 S 114 50 31.964 E 199

    GOR-3B 20 31 11.275 S 114 49 25.845 E 199

    GOR-3C 20 31 11.835 S 114 49 26.424 E 199

    To minimise environmental impact, and to maximise drilling efficiency, safety, and operationsmanagement, the batch drilling will follow this schedule of works:

    At Manifold 3, the top-hole section on GOR-3B will be drilled and cased before the rig movesto GOR-3C. GOR-3C will then be drilled through to partial completion (cemented casingstrings) and well suspension. The rig will then move back over GOR-3B and partiallycomplete the wells through to suspension before moving to subsea Manifold 1.

    At Manifold 1, the top-hole sections on all four wells (GOR-1C, GOR-1D, GOR-1E and GOR-1F) will be drilled before the rig commences partial completion and well suspension on GOR-1E, followed by GOR-1C, GOR-1D, and GOR-1F. The rig will then move to subseaManifold 2.

    At Manifold 2, the top-hole sections of GOR-2B and GOR-2C will be drilled. Well GOR-2Cwill then be partially completed and suspended before the rig moves back to GOR-2B tocomplete the drilling of the well to completion.

    Well GOR-2B will be the first well completed, following the batch drilling phase. The batchcompletion of the Gorgon wells will proceed in the reverse order in which they were drilled.Each well will be terminated at the seabed by a horizontal subsea tree. SeeFigure 1-2 for welland manifold locations. Coordinates of the proposed wells are given inTable 2-1.

    The batch drilling phase for each well is scheduled for 52 days, and the batch completion phaseis scheduled for 38 days. The scheduled days are estimates and are exclusive of additionaltiming that could result from adverse weather, equipment delays, rig downtime or well problems

    etc.

    The program does not include any post-completion tie-in or other operations, and hence doesnot involve hydrotest fluid or produced formation water handling or disposal.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    29/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 32 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Figure 2-1 Bathymetry at Manifold and Well Locations

    2.2 Well Design and Drilling Details

    The wells have been designed in accordance with Chevron Corporate and Chevron AustraliaStandards, accepted industry practices, and DMP regulatory requirements. Wells will besuitable for all conditions that might be expected during drilling operations.

    2.2.1 Design

    The eight Gorgon development wells will be designed as shown inTable 2-2 andTable 2-3. Allwells will be of similar design.

    Table 2-2 Gorgon Development Well Design Details

    Hole size Casing size Depth BelowSeabed

    Length ofHole Section

    Volume ofcuttings

    Drilling Fluid

    Inch mm Inch mm m m bbl m3

    42 1067 36 914 70 70 590 95 Sea water with

    high viscositysweeps

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    30/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 33

    Printed Date: 7 July 2011 Uncontrolled when Printed

    Hole size Casing size Depth BelowSeabed

    Length ofHole Section

    Volume ofcuttings

    Drilling Fluid

    Inch mm Inch mm m m bbl m3

    26 660 20 508 400 330 950 151 Sea water with

    high viscositysweeps

    17 444 14 340 1800 1,400 1549 246 Synthetic-basedMud (SBM)

    13 343 10 244 3200 1,400 813 129 SBM

    8 222 7 178 5200 2,000 540 86 SBM

    Table 2-3 Gorgon Development Well Total Cuttings Volumes (per well)

    Cuttings Volumes Volume (bbl) Volume (m3)

    Water-based Mud (WBM) 1540 246

    Synthetic-based Mud (SBM) 2902 461

    Total 4442 707

    The upper sections of each well (42 and 26 hole sections) will be drilled riserless, using seawater with high viscosity sweeps. The remaining sections of each well will be drilled with amarine riser and Blow-Out Preventers (BOP) installed and using a synthetic-based drilling fluid(SBM), namely NOVATEC.

    Drilling will be conducted to a target depth of approximately 5200 m below the seabed. Coreswill also be taken in targeted reservoirs in the well.

    Cuttings volumes provided in Table 2-3 are indicative of volumes to be generated anddischarged for each well.

    2.2.2 Drilling Fluids and Chemical Additives

    Shallower sections of the wells will be drilled using sea water with high viscosity gel sweeps.The remaining sections of the well will be drilled using SBM in a closed-fluid system. Theselected SBM NOVATEC, provided by MI Swacohas been chosen for improved safety,environmental, operational, and economic performance (reduced time on location, better wellcontrol).

    NOVATEC is a Saraline 185V based SBM. This SBM has been assessed to be non-toxic toalmost non-toxic and has previously been approved by DMP for drilling operations in WesternAustralia (WA). Characteristics of the drilling fluids to be used during the drilling operations,including ecotoxicity information, are described briefly below.

    2.2.2.1 Water-based Drilling Fluids (WBM)

    The proposed WBM will be a sea water/high viscosity sweeps (bentonite) mixture, which isconsidered to have minimal environmental effect (see Section4.3.1.1).

    2.2.2.2 Synthetic-based Drilling Fluids (SBM)

    The preferred fluid system for the drilling program is the NOVATEC fluid system, previously

    approved by DMP for other drilling operations in WA, which contains a Saraline 185V base fluid.According to the DMPstoxicity ratings system (DoIR 2006), the components of NOVATEC(whole mud) are considered non-toxic to almost non-toxic and biodegradable (see Section

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    31/160

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    32/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 35

    Printed Date: 7 July 2011 Uncontrolled when Printed

    Manager (DSM) onboard. For SBMs, the target recovery will be

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    33/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 36 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    practicable) any debris in the drilling area and to provide a record of the size and position of anycuttings piles (if present).

    The results of the surveys will be included in close-out environmental reporting.

    2.2.7 Logging

    The wells will be evaluated with a standard wireline logging suite, including sidewall cores,formation samples, and, on some wells, Vertical Seismic Profile (VSP). The VSP acousticsource will consist of a 750 cubic inch three airgun array. The airgun array will generateacoustic pulses five times at 20 second intervals every five to seven minutes for each depthlevel, and is expected to take between six and 12 hours per well. The maximum noise levelexpected to be generated is approximately 195 dB re 1 Pa @ 1m. VSP operations will beundertaken in accordance with cetacean interaction procedures, discussed in Section6.3.2.

    2.2.8 Well Testing and Clean-Up

    The wells will be subject to a clean-up well flow test to 60 to 75 MMscf/day at the end of thecompletion phase, prior to production. Well flow clean-up is planned to be no longer than12 hours per well, commencing in daylight but possibly continuing into the night. Rates of flaredgas and liquids will be recorded, and reported as per the National Pollutant Inventory (NPI)requirements and the National Greenhouse and Energy Reporting Act 2007 (Cth) (NGER Act)guidelines (Commonwealth Government of Australia 2008).

    2.2.9 Well Suspension and Completion

    At the completion of the batch drilling phase of development, wells will be cased and cemented,and will be suspended (or, in the event a dry hole, plugged and abandoned) in accordance withthe requirements of the OPGGS Act and industry best practice. A tested retrievable packer willbe set in the well bore, which will later be recovered during the completion phase.

    When all eight wells are batch drilled, the wells will be batch completed in the reverse order thatthey were drilled. After the Horizontal Trees have been fitted, and the BOPs and riser havebeen landed out, tubing will be run in the well, the reservoir zones will be perforated, and clean-up flows undertaken ready for production. The wells will be fitted with a surface-controlledsubsurface safety valve (SCSSV) designed to slam shut in the event of wellhead or treedamage. An exclusion zone will be established around the manifolds and subsea infrastructure.

    Completion brine will be discharged during well completion when the fluid will be displaced fromthe well. Approximately 500 bbl of sodium bromide (solution of 27% mixed with fresh water) willbe discharged per well.

    Seabed surveys of the well location will be conducted by ROV to check for (and recover wherepracticable) any debris in the vicinity of the well, and to provide a record of the size and positionof any cuttings piles (if present).

    2.2.10 Marine and Support Operations

    2.2.10.1 Rig and Support Vessels

    The Atwood Osprey rig is a semi-submersible, moored drilling rig. The Atwood Ospreywasconstructed in the Jurong Shipyard in Singapore and was towed into Australian Commonwealthwaters for Chevron Australias drilling program in May 2011. TheAtwood Ospreyhas a 12-pointanchoring system, comprising three anchors off each corner of the main deck of the rig. Thefootprint of each anchor on the seabed is 5.5 m (length) by 6.0 m (wide).

    The rig is supported by two dedicated Anchor Handling, Tug and Supply Vessels (AHTSV)supplied by Farstad Shipping, the Far Shogun and Far Saracen. Both support vessels areClass 2 Dynamic Positioning (DP2) vessels. The rig may also share, as required, supportvessels for the Atwood Eagle rig, namely the Maersk Supporter and the Maersk Searcher,mobilised for exploration drilling activities in nearby exploration permits. All support vessels willoperate out of the Port of Dampier.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    34/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 37

    Printed Date: 7 July 2011 Uncontrolled when Printed

    The two support vessels will be used primarily to supply the rig, support drilling operations, andtow the rig between drilling sites, but they will also provide search and rescue functions. Allsupport vessels will be fitted with Shipboard Oil Pollution Emergency Plan (SOPEP) equipmentin accordance with MARPOL 73/78 requirements.

    The rig will be serviced by helicopters based on Barrow Island. Helicopter flight frequency will

    be on average one per day and will primarily be used for passenger transfers/crew changes,and minor supplies. All crew changes for the rig will be conducted by helicopter, with rotationsscheduled every 21 to 28 days. The rig has the capacity for a maximum Persons on Board(POB) of 200 personnel, with an operational personnel capacity of 145 to 160 POB. Crewchanges for the support vessels will be conducted in the Port of Dampier, with rotationsscheduled every 28 to 35 days. The support vessels are capable of a maximum POB of40 personnel each, with an operational personnel capacity of 16 POB for each vessel.

    2.2.10.2 Refuelling

    Refuelling will be conducted for theAtwood Ospreyrig from the two AHTSVs in accordance withthe Atwood Diesel Fuel Oil Bunkering procedures outlined in the Atwood Osprey OperationsManual, Section 6.3 (in prep). Dedicated transfer hoses with dry break couplings and safety

    breakaway fittings will be used. Pressure tests (120 psi hose integrity test) will be conductedprior to transfers to verify the integrity of the hoses and piping. Refuelling may occurapproximately twice a week for the duration of the drilling program.

    2.2.11 Time Frame

    The drilling program will commence in June 2011. Drilling each Gorgon well will takeapproximately 90 days (52 days drilling and 38 days well completion), including relocationbetween sites. The program is expected to continue until all wells are drilled and completed,which is anticipated to be by the end of 2013. Drilling operations will be conducted 24 hours aday.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    35/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 38 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    3.0 Existing Marine Environment

    3.1 Physical Environment

    3.1.1 Bathymetry and Seabed Features

    The eight Gorgon development wells are located in waters off the Australian continental shelf,with water depths ranging from 199 to 215 m. These wells are located approximately 60 kmfrom Barrow Island and 155 km from the mainland (North West Cape is the closest point). Thenorthernmost portion of the Gorgon gas field is gently sloping and dissected by a north-west tosouth-east aligned ridge (Chevron Australia 2005). The southern extent of the gas field ischaracterised by deeply undulating valley terrain (Chevron Australia 2005). Benthic marinehabitats were surveyed for the Gorgon Gas Development using a combination of side-scansonar and video transect. Survey results indicated the seabed of the gas field would beexpected to comprise bioturbated soft sediments, and benthic habitats of the field are likely tobe widespread throughout the Montebello-Lowendal-Barrow Island region (Chevron Australia2005). Surveys conducted just north of the proposed drilling area in similar water depths (238to 264 m) showed the substrate to be predominantly silty muds (RPS 2009). There was

    evidence of burrow holes in soft sediment, likely from worms, small fish or crustaceans, andoccasional sparse communities of crinoids, sponges and gorgonians associated with areas ofconsolidated sediments and scattered rubble (RPS 2009). Based on current knowledge, nosensitive ecosystems have been identified.

    3.1.2 Metocean Conditions

    The region is generally characterised by two seasons: summer (SeptemberApril) and winter(MayAugust) (Pearce et al.2003). The climate in winter is dominated by intense anti-cyclonicbelts (high pressure systems), which generate strong winds (predominantly from the east andsouth-east) and infrequent rain. Summer conditions are more variable, with varying winddirections (although south-westerly winds are the most common) (Pearce et al. 2003).

    The area typically experiences a persistent winter swell of around 2 m, generated by lowpressure systems in the southern latitudes (Pearce et al. 2003). During winter, strong easterlywinds can also generate 2 m seas. Both swell and seas tend to be smaller during summer.

    Tropical cyclones occur in the region, with an average of five per year (Bureau of Meteorology2011). According to the Bureau of Meteorology, the Australian region tropical cyclone seasonruns from 1 November to 30 April (Bureau of Meteorology 2011). Tropical cyclones areunpredictable in occurrence, intensity and behaviour, but are most common between Decemberand March, and can generate extreme seas and swell.

    Water circulation in the area is influenced by the southward-flowing oceanic Leeuwin Current.The Leeuwin Current is strongest in winter, flowing steadily to the south-west at up to 0.3 m/s(Holloway and Nye 1985).

    Tides are strongly semidiurnal, with four tide changes per day. The dominant tidal current flowsin summer are east-north-east and west-south-west, with speeds generally ranging from 0.1 to0.3 m/s (Pearce et al. 2003).

    Near-surface water temperatures of the North West Shelf range from 31 C maximum insummer, to 22 C minimum in winter (Chevron Australia 2005), with an average of 26.8 C anda mixed layer of 35.7 m.(Brewer et al. 2007). The mean water temperature for depths between200 and 250 m is around 10 C (Chevron Australia 2003).

    3.2 Marine Biological Environment

    Condition 3.2.1 of EPBC Reference: 2003/1294 and 2008/4178 requires a description of theEPBC Act listed species and associated habitats likely to be impacted by the components of the

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    36/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 39

    Printed Date: 7 July 2011 Uncontrolled when Printed

    action that is the subject of this Plan. The EPBC Act listed species and associated habitats aredescribed inAppendix 1.

    Condition 3.2.2 of EPBC Reference: 2003/1294 and 2008/4178 requires an assessment of therisk to EPBC Act listed species (detailed inAppendix 1)from the components of the action. AnEPBC Act Protected Matters search was also conducted specifically for Permit Area WA-37-L

    (Appendix 2).

    3.2.1 Benthic Flora and Fauna

    Marine biological surveys indicate that subtidal habitats near the Gorgon gas field, which lies in200 m of water, comprise soft, bioturbated sediments (Chevron Australia 2005). The benthos inthis area is well below the photic zone so there are no marine macrophytes (marine flora). Fineorganic particles settle from the water column to form deep silt and mud.

    The sea floor at specific well locations is likely to be typical of those across the permit area andacross broad expanses of the North West Shelf, comprising predominantly unconsolidated softsediments inhabited by sparse communities of relatively large benthic species (crustaceans,molluscs, and sponges). Infaunal communities are likely to be predominantly smaller burrowing

    invertebrates. Any areas of exposed hard substrate that occur may support more diverseassemblages, including deepwater filter-feeding organisms, such as hydroids and sponges.

    Prior to the commencement of drilling, surveys, using ROV and/or other subsurface imagingtechniques, will be used to confirm the absence of significant environmental features andidentify any sensitive marine ecosystems at drilling locations. Specific well locations andflowline paths will be selected to avoid sensitive marine ecosystems, and wells will bedirectionally drilled from three subsea manifold locations, reducing the impact and footprint onthe seabed.

    3.2.2 Macrofauna

    The offshore environment of the permit area is typical of wide expanses of the continental slope

    and does not represent habitat of particular significance for any macrofauna.Some marine migratory species with broad distributions, such as cetaceans, fish, sharks,marine turtles and seabirds, may traverse the permit area occasionally (CommonwealthDepartment of Sustainability, Environment, Water, Population and Communities [SEWPaC]2010a). Under the EPBC Act, nine species listed as Threatened and 16 listed as Migratory mayoccur in Permit WA-37-L (Table 3-1;Appendix 2). However, the permit area does not containrecognised critical habitat for any Threatened or Migratory fish, sharks, marine turtles,cetaceans, or seabirds.

    Further details regarding the main fauna groups that might occur in the area are provided in thefollowing sections.

    Table 3-1: EPBC Act Listed Threatened Species that may Occur within the Permit Area

    Common Name Scientific Name EPBC Act Status

    Fish

    Whale Shark Rhincodon typus Vulnerable; Migratory

    Longfin Mako Shark Isurus paucus Migratory

    Shortfin Mako Shark Isurus oxyrinchus Migratory

    Reptiles

    Flatback Turtle Natator depressus Vulnerable; Migratory

    Green Turtle Chelonia mydas Vulnerable; Migratory

    Hawksbill Turtle Eretmochelys imbricata Vulnerable; Migratory

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    37/160

    Environment Plan: Document No.: G1-NT-PLNX0001023

    Gorgon Gas Development Drilling and Completion Program DMS ID: 00391225

    Revision: 0 Revision Date: 9 June 2011

    Page 40 Public Chevron Australia Pty Ltd

    Uncontrolled when Printed Printed Date: 7 July 2011

    Common Name Scientific Name EPBC Act Status

    Leatherback Turtle Dermochelys coriacea Vulnerable; Migratory

    Loggerhead Turtle Caretta caretta Endangered; Migratory

    Birds

    Southern Giant-Petrel Macronectes giganteus Endangered; Migratory

    Mammals

    Antarctic Minke Whale Balaenoptera bonaerensis Migratory

    Blue Whale Balaenoptera musculus Endangered; Migratory

    Brydes Whale Balaenoptera edeni Migratory

    Humpback Whale Megaptera novaeangliae Vulnerable; Migratory

    Killer Whale Orcinus orca Migratory

    Sperm Whale Physeter macrocephalus Migratory

    Spotted Bottlenose Dolphin(Arafura/Timor Sea populations)

    Tursiops aduncus Migratory

    3.2.2.1 Fish

    A number of sharks and pelagic finfish, including mackerel, tuna and billfish, occur in the watersof the North West Shelf and would be expected to occur in the permit area. The deep offshoreenvironment of the permit area is typical of the continental slope of north-western Australia andis not expected to represent habitat of particular significance to sharks and finfish.

    Whale Sharks have a broad distribution in tropical and warm temperate seas. They feed onphytoplankton, macro-algae, plankton, krill and small nektonic life, such as small squid orvertebrates. Whale Sharks undertake a well-known annual migration to aggregate at NingalooReef (140 km from the closest development well) between March and July each year (Wilson etal. 2006). Yearly numbers of Whale Sharks at Ningaloo Reef are estimated to vary from 200 to400 individuals. This seasonal aggregation is thought to be linked to localised seasonal peaksof productivity, likely associated with a mass coral spawning event that occurs around March toApril each year. After July, the Whale Sharks disperse widely, mainly in a north-east directiontowards Indonesian waters. Whale Sharks are expected to occur only in very low numberswithin the permit area, due to the distance between the proposed wells and Ningaloo Reef.

    The Longfin Mako Shark is a widely distributed, but rarely encountered, oceanic tropical shark.This species can grow to just over 4 m and is found in Western Australian waters north ofGeraldton. The Shortfin Mako Shark is a pelagic species with a circumglobal, wide-ranging,oceanic distribution in tropical and temperate seas (Mollet et al. 2000), and is widespread inAustralian waters.

    Given their wide-ranging habitat and highly transient nature, Shortfin and Longfin Mako Sharks

    may occur within the permit area. However, there are no bathymetric features or aggregationareas of importance for these species within the permit area. Therefore, these species are onlylikely to occur in very low numbers.

    3.2.2.2 Seabirds

    The Southern Giant-petrel is listed as Endangered under the EPBC Act and may be found in thepermit area. The Southern Giant-petrel is widely distributed; it breeds in sub-Antarctic watersduring the summer, while in winter most disperse north from 50 S to the Tropic of Capricorn(Environment Australia 2001).

    There are no important feeding grounds known for this species near the permit area, and giventhe distance from land, foraging activity is likely to be low. Due to the widespread distribution of

    the Southern Giant-petrel, numbers at any given location are likely to be low.There are no islands or other areas of known seabird breeding significance, or importantfeeding grounds for seabirds, within or close to the permit area.

  • 7/26/2019 Gorgon Emp Gorgon Gas Development Drilling and Completion Program

    38/160

    Document No: G1-NT-PLNX0001023 Environment Plan:

    DMS ID: 00391225 Gorgon Gas Development Drilling and Completion Program

    Revision Date: 9 June 2011 Revision: 0

    Chevron Australia Pty Ltd Public Page 41

    Printed Date: 7 July 2011 Uncontrolled when Printed

    3.2.2.3 Reptiles

    Five species of marine turtles may occur in the permit area: Flatback, Green, Hawksbill,Leatherback and Loggerhead Turtles.

    Flatback Turtles are found only in the tropical waters of northern Australia, Papua New Guinea,and Irian Jaya. All recorded nesting beaches are in Australia (Limpus et al. 1989). The

    Kimberley region of Western Australia, Cape Dommett, and Lacrosse Island are importantnesting areas (Bowlay and Whiting 2007). The nearest Flatback Turtle aggregation and nestingsites are located on Barrow Island (SEWPaC 20