key issues report

EPA Key Issues Report Tui decommissioning marine consent & marine discharge consent application EEZ100020

Key Issues Report

Ministry of Business, Innovation & Employment

Tui Field Decommissioning

EEZ100020

SEPTEMBER 2021

EPA Key Issues Report Tui decommissioning marine consent & marine discharge consent application EEZ100020

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Contents

Contents ................................................................................................................................................. 1

Introduction ............................................................................................................................................ 2

Purpose of this Key Issues Report ...................................................................................................... 2

Decommissioning of the Tui Field ....................................................................................................... 4

Background ......................................................................................................................... 4

The decommissioning proposal .......................................................................................... 5

The Applications .................................................................................................................................... 6

Application documents .................................................................................................... 6

Activities requiring consent under the EEZ Act: ........................................................... 6

The Impact Assessment........................................................................................................................ 8

Geographical Context ......................................................................................................... 8

Existing Environment: ......................................................................................................... 8

Environmental Impacts: ....................................................................................................... 9

Statutory decision-making framework .............................................................................................. 12

Purpose ............................................................................................................................. 16

HSNO Approvals ............................................................................................................... 16

2020 Hazard Classification Notice ................................................................................... 16

Key Issues ............................................................................................................................................ 17

Introduction ........................................................................................................................ 17

Ecological Receptors & Seasonal Sensitivity .................................................................... 17

Biosecurity Risk Management........................................................................................... 19

Seabed Disturbance .......................................................................................................... 19

Well Plugging & Abandonment ......................................................................................... 21

Discharge Uncertainties .................................................................................................... 24

Existing interests & Te Ao Māori ....................................................................................... 30

Environmental Monitoring ................................................................................................. 30

Conclusions and Recommendations ................................................................................................ 32

EPA Key Issues Report EEZ100020 Marine consent & Marine discharge consent

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Introduction

My name is Tim Roser. I am a Senior Advisor employed by the Environmental Protection Authority

(EPA).

I have technical and regulatory experience in the resource development sector including

environmental monitoring, research, and stakeholder engagement. I have BSc degrees in geology and

physical geography from the University of Otago and have worked as an exploration geologist in

Australia and Europe. I have previously assisted EPA decision makers with the processing of several

applications for marine consents and marine discharge consents.

Before joining the EPA, I provided technical and regulatory advice for MBIE and New Zealand

Petroleum and Minerals. Due to my previous work at New Zealand Petroleum and Minerals, a division

of MBIE, I still hold some social and professional networks with staff within that Ministry. However, this

does not extend to MBIE's Tui Project Team and the only interactions I have had with that team are in

my professional capacity on behalf of the EPA.

I have read the Ministry of Business Innovation and Employment (MBIE)’s application forms, the

impact assessment (IA), the commissioned external technical reviews, and comments received from

relevant government agencies. The documents listed in Appendix 1 have formed the basis for this

report.

Purpose of this Key Issues Report

The purpose of this report is to highlight some of the key issues that may be relevant for the Board of

Inquiry in reaching its decision, in respect of the notified and non-notified application.

The Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012 (the EEZ Act)

requires the EPA to provide a Key Issues report in respect of the notified application under section 100

and Schedule 4 clause 1 of the EEZ Act, that includes reporting on any relevant provisions in

regulation and a statement on whether the application covers all aspects of the activity for which a

marine consent is required.

While a Key Issues Report is not required for the non-notified marine discharge consent, I also discuss

this application, where relevant.

In terms of Schedule 4 clause 2 (ii) of the EEZ Act, the applications submitted by MBIE covers all

aspects of the activities for which marine consent and marine discharge consent are sought and a

“completeness” decision was made by the EPA in this regard, on 18 August 2021 under section 40 of

the EEZ Act.

This report comprises only one of a number of documents the Board will consider in reaching its

decision on the applications. Other relevant material that will be consider by the Board includes the

application documents and supporting information, any information obtained through sections 54 and

56 of the EEZ Act, submissions, relevant provisions of the Act, and evidence.


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In preparing this report, information from reports commissioned by the EPA and prepared by

independent consultants with expertise in marine ecology1, the decommissioning of oil fields2 and

ecotoxicological discharge assessment3 to support the identification of key issues relating to the

application. The report also draws on information and advice provided by a number of government

agencies.4

This report has been prepared based on information that was available at the time of writing.

Accordingly, it doesn’t include consideration of issues raised in submissions or evidence.

While the issues discussed in this Key Issues Report are those that I consider to be ‘key’, the impact

assessment and supporting documents identify other issues and effects associated with the proposal.

The fact that I do not discuss these other issues in this report should not be construed or interpreted to

mean that those other matters are irrelevant. Any other matters that may be identified through

evidence, or through any subsequent report commissioned by the Board are still matters that the

Board may make findings on when it considers the application and makes its decision.

This Key Issues Report deliberately does not provide an assessment of the effects of the application,

or a conclusion/recommendation on whether the applications should be granted or refused.

This Key Issues Report includes discussion on where the technical experts commissioned by the EPA

under section 56 of the EEZ Act have raised issues regarding certain parts the application documents

(e.g. recommendations, or highlighting of information gaps). The Board will need to decide whether it

has the ‘best available information’ in respect of such matters. Section 61(1)(b) the EEZ Act

(Information principles) requires the Board to base its decision on the best available information. This

is defined as meaning ‘the best available information that, in the particular circumstances, is available

without unreasonable cost, effort, or time’.

To meet its obligations to obtain the best available information under section 61 of the EEZ Act, the

Board may commission further reports or request information from the applicant.

This Key Issues Report suggests topics on which the Board may wish to seek further information or

clarification. If the Board decides it requires further information to pursue the matters raised in this

report with respect to best available information, then it will also need to decide how and when it will

obtain the information.

I have also noted the conditions proffered by the application and noted issues that the Board may

wish to consider further conditions if it was of a mind to grant the consents.

1 Pattle Delamore Partners 2 Intecsea 3 COPE Environmental Consultancy Limited 4 WorkSafe New Zealand, Maritime New Zealand, Fisheries New Zealand, Biosecurity New Zealand & the Department of

Conservation


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Decommissioning of the Tui Field

Background

The Tui Field is within Petroleum Mining Permit (PMP) 38158, located ~50km west of the Taranaki

coastline in water depth of approximately 120m within the Taranaki Basin (see Figure 1).

Figure 1: The location for MBIE’s proposed decommissioning programme and PMP38158.

After the unsuccessful exploration to extend the production life of the Tui field in 2019, Tamarind

Taranaki Limited (Tamarind) became financially insolvent in November 2019.

The Tui field contains assets such as subsea well heads, flowlines, and risers which were previously

owned by Tamarind but are now vested to the Crown. The production of oil to the Floating Production

Storage and Offloading vessel (FPSO) “Umuroa” ceased and the Crown commenced

decommissioning the Tui field.

The Umuroa is owned by BW Offshore and was contracted by Tamarind for the operation of the

FPSO. Phase 1 of the Tui field decommissioning programme began in January 2021 to flush and

disconnect the production lines that were attached to the Umuroa and the mooring system that held

the vessel in place for the last 14 years. The Umuroa, once disconnected, departed in May 2021, and

the anchors and mooring lines were removed.


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The decommissioning proposal

The overall decommissioning programme for the Tui field comprises three phases. The first phase was

completed in May 2021 with the disconnection and removal of the Umuroa. The remaining phases are

the removal of the subsea infrastructure (SSI) (Phase 2) and the plugging and abandonment (P&A) of

eight wells (Phase 3). Some of the proposed activities associated with these remaining phases are

restricted by the EEZ Act and are the subject of MBIE’s applications.

Of the five production wells in the Tui Field, it is understood that one (Tui-3H) has been suspended and

plugged and the remaining four have associated umbilicals, production flow lines and gas-lift lines that

extend from the well locations to a central location where the FPSO was moored. The decommissioning

works to be undertaken are essentially the removal of these lines and their associated rigging and

infrastructure, the removal of wellhead structures and the plugging of the wells themselves using a

cement slurry.

The umbilicals, production flow lines and gas-lift lines will all need to be disconnected from the wellhead

structures and lifted, either whole or in pieces, to the surface, along with their associated rigging, weights

and infrastructure. The production flow lines and gas-lift lines have been flushed and filled with a biocide

inhibited seawater solution. That solution will need to be emptied from the flow lines and gas-lift lines (i.e.

discharged to the environment) as they are retrieved from the seabed.

The methodology for the proposed well plugging works involves introducing a cement slurry into the well

casings at an appropriate level to produce an effective physical plug to prevent any discharge from each

well. Following the successful plugging of each well, the well abandonment procedure will involve the

removal of wellhead structures and cutting the well casing off 3m below seabed level.

It is understood that the suspended production well Tui-3H and the three plugged (but not abandoned)

exploration wells will principally require the removal of wellhead structures and that these wells do not

have production flow lines, gas-lift lines, umbilicals and related infrastructure associated with them.

The aim of the decommissioning proposal is to remove all infrastructure and to leave a clear seabed

surface without any weights, cables, pipes, anchors or other man-made items.

If the marine consent is granted, MBIE anticipates that the works will take place over two years during

the summer months (December to April) to minimise exposure to delays caused by weather. The

duration of consent sought is until December 2030 to allow environmental monitoring after the work has

taken place and any delays to the programme.


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The Applications

On 21 July 2021, MBIE lodged two applications under EEZ100020 – a notified marine consent

(EEZ100020-1) and a non-notified marine discharge consent (EEZ100020-2).

The EPA is required to publicly notify the marine consent application under section 46 of the EEZ Act.

While the EPA is required to serve copies of the marine discharge consent application on certain

parties under section 45 of the EEZ Act, the application is not open to public submissions.

Section 52 of the EEZ requires the notified marine consent application to be considered by a Board of

Inquiry appointed by the Minister for the Environment. To enable joint consideration, the EPA has

delegated its decision-making powers and functions for the non-notified marine discharge consent

application to the Board.

Application documents

The application documents consist of two completed application forms and an impact assessment with

ten appendices. For the purposes of this report I make reference to the following (with their

corresponding meaning):

a. ‘the applications’ means the completed prescribed application form documents entitled “Marine

Consent Application Form – EEZ100020” and “Marine Discharge Consent Application Form –

EEZ100020” (dated July 2021);

b. “the IA” means the Impact Assessment, being the report provided in support of both the marine

consent application and the discharge consent application entitled “Tui Field Decommissioning

Marine Consent and Marine Discharge Consent Application” (SLR Ref: 740.30008.00000-R01,

Version No: -v1.0) prepared by SLR Consulting NZ Limited (SLR) (dated July 2021); and

c. “Appendix X of the IA” (where X denotes an alphanumeric between A and J) means the

respective appendix attached to the IA.

Activities requiring consent under the EEZ Act:

Section 2 of the IA describes the decommissioning programme activities that are restricted under

section 20 and 20B of the EEZ Act and for which consent is sought for. These activities are listed in

Table 14 and section 2.7 of the IA.

Notified marine consent

The marine consent application involves activities that are restricted under section 20 of the EEZ Act

and are classified as notified discretionary activities. The IA describes seven components of the

decommissioning programme that involve restricted activities under section 20 of the EEZ Act (see

Appendix 1), and for which marine consent is sought. The seven components are:

a. Retrieval of production flowlines, umbilicals, and gas-lift coil tubing from the seabed.

b. Retrieval of Mid Water Arches (MWA) and Gravity Base (GB).


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c. Retrieval of miscellaneous subsea equipment (gas-lift jumpers, hydraulic flying leads, electric

flying leads, gas lift manifold, hold back anchors).

d. Installation and removal of Mobile Offshore Drilling Unit (MODU) and its removal after the work

has been carried out.

e. Plugging and Abandonment of Wells.

f. Post-decommissioning environmental monitoring.

g. Contingent activities (including planned and unplanned disconnection of blowout prevent (BOP),

additional cement plugs, external cutting of wellhead, use of down-hole explosives, and disposal

of faulty cement .

Section 20 of the EEZ Act outlines restrictions on activities that can be undertaken in the Exclusive

Economic Zone (EEZ), and in or on the continental shelf. No person may undertake an activity

described in section 20 unless the activity is a permitted activity, is authorised by a marine consent, or

is authorised by sections 21, 22, or 23 of the EEZ Act. The seven components of the decommissioning

programme outlined in paragraph 4 of this report, involve activities that are restricted under section 20

and require marine consent.

Non-notified marine discharge consent

The marine discharge consent application involves activities that are restricted under section 20B of

the EEZ Act. The activities are classified as non-notified discretionary activities under Regulation 20 of

the Exclusive Economic Zone and Continental Shelf (Environmental Effects – Discharge and

Dumping) Regulations 2015 (D&D Regulations) as the discharge of harmful substances are from a

mining activity.

The IA describes four components of the decommissioning programme that may result in discharges

of harmful substances to the marine environment. The marine discharge consent is being sought as

these discharge activities are classified as restricted activities under section 20B of the EEZ Act. The

four components associated with the discharge consent application are:

a. The discharge of biocide inhibited seawater;

b. The discharge of residual hydrocarbons;

c. The discharge of BOP fluid; and

d. The discharge of cement additives.

Section 20B of the EEZ Act outlines restrictions on discharge activities that can be undertaken in the

EEZ, and in or on the continental shelf. No person may discharge a harmful substance into or onto the

seabed of the EEZ from a structure or a submarine pipeline unless the activity is a permitted activity, is

authorised by a marine consent, or is authorised by sections 21, 22, or 23 of the EEZ Act. The four

components of the decommissioning programme that involve discharge activities are restricted under

section 20B and regulated under D&D Regulations. Regulations 20 of the D&D Regulations classifies

these discharge activities as non-notified activities.


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The Impact Assessment

Geographical Context

MBIE has defined an Impact Assessment Area (IAA) to assess the impacts associated with the

decommissioning of the Tui field (see Figure 2). With a 1500m buffer, the ~122km2 IAA encompasses

the Tui Protected Area specified in the Submarine Cables and Pipelines Protection (Tui Area

Development) Order 2007, the subsea infrastructure to be removed (Phase 2) and the wells that will

be subject of the well plugging and abandonment activities (Phase 3).

Figure 2: Impact Assessment Area for phase 2 & 3 of the Tui field decommissioning programme.

Existing Environment:

Section 4 of the IA describes the existing environment of the IAA. The offshore Taranaki region is

considered to have a high-energy wave climate. The majority of the wave energy arrives from the west

and southwest, with southerly waves able to rapidly rise. The currents within the IAA are described

within section 4.2.3 based on MetOcean Solutions (2018) modelling of hindcast data. The physical

environment of the IAA is described further within section 4.2 of the IA and includes information about


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Te Ao Māori, meteorology, currents and waves, thermoclines and sea surface temperature, water

quality, ambient noise, bathymetry, geology, seafloor sediments and substrate.

The existing biological environment of the IAA is described in Section 4.3 of the IA. This includes

microphytobenthos, benthic invertebrates, sensitive and protected species, fish, cephalopods, marine

mammals and seabirds. Further detail is provided in Sections 4.3.1 to 4.3.7.4 of the IA provides

information on the presence and distribution of each of these biological groups in the IAA. Section

4.3.3 of the IA describes any sensitive environments observed in the region based on the definitions

under the Permitted Activity Regulations.

The IA notes that the description of the physical environment is largely based on a western science

perspective acknowledges holistic views of the environment based on whakapapa, whanaungatanga,

connecting mana whenua and all physical and spiritual things in the world. The Te Ao Māori

perspective of the physical environment is described in section 4.4 and the Cultural Impact

Assessment (CIA) in Appendix E of the IA.

Section 4.4 of the IA describes the cultural environment in relation to the Taranaki Basin. This includes

customary fishing and iwi fisheries interests, statutory acknowledgment areas, interests under the

Marine & Coastal Area (Takutai Moana) Act 2011, Coastal Taonga Species and sites of significance to

Māori. Section 4.5 of the IA describes the socio-economic environment including commercial and

recreational fishing, shipping, and oil and gas activities.

Environmental Impacts:

Section 7 of the IA provides an environmental risk assessment on the proposed activities and their

associated environmental effects. The IA identifies actual and potential effects under the marine

consent as including the temporary presence of objects in the water column, seabed disturbance,

removal of artificial hard substrata, noise and vibration including the potential use of explosives.

MBIE's environmental risk assessment (ERA) is described in sections 7.2.1, 7.3.1 and 7.11 of the IA

and summarised in Table 1 and Table 2 below.

The IA describes how the worst-case scenario effects from the proposed decommissioning activities

are localised geographically around the wells and removal sites and that the most geographically

extensive effects will be from sediment suspension and deposition due to seabed disturbance. These

environmental effects are expected to fall within the extent of the delineated IAA (see Figure 2).

The extent of potential effects from seabed disturbance are discussed in Section 7.2.3.2 of the IA.

Section 4.2.8 and Section 7.2.3.2.3 of the IA describes that during the proposed decommissioning

activities, seabed disturbance in the form of sediment suspension and deposition is a certain effect

due to the silty clay substrate and will be a common consequence of placing, moving or removing

equipment and SSI from the seabed. Table 30 of the IA, summarises the predicted areas of seabed

disturbance for each individual activity that will or may form part of the decommissioning of the Tui

field. The maximum total area of seabed disturbances of all of the proposed decommissioning

activities is predicted to be no more than 150,763m2 or 0.151km2. This equivalent to 0.12% of the

122km2 IAA (Figure 2). However MBIE note in the IA that some of the activities that they have applied


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for consent may not be used when they undertake the decommissioning programme. For example,

some of these activities are contingent on whether they use a MODU instead of a Well Intervention

Vessel (WIV).

Table 1: The IA risks & magnitude of environmental impacts from the proposed marine consent activities.

Environmental impacts Consequence

Likelihood Risk Predicted Magnitude of

environmental effects

Temporary presence of objects in

the water column – displacement or

entanglement effects on marine

mammals

1 – Minor 1 – Remote 1 – Very low Almost Negligible

Temporary presence of objects in

the water column – ship strike

effects on marine mammals

1 – Minor 1 – Remote 1 – Very low Almost Negligible

Temporary presence of objects –

effects on seabirds

1 – Minor 2 – Rare 2 – Very low Almost Negligible

Seabed disturbance – effects on the

benthic communities

1 – Minor 6 – Certain 6 – Moderate Minor

Seabed disturbance –effects on

marine mammals

1 – Minor 3 – Unlikely 3 – Low Less than minor

Removal of artificial hard substrate –

effects on artificial reef invertebrate

assemblages

1 – Minor 6 – Certain 6 – Moderate Minor


effects on fish and cephalopods

1 – Minor 5 – Likely 5 - Low Less than minor


effects on marine mammals

1 – Minor 5 – Likely 5 - Low Less than minor

Noise and Vibrations – effects on

marine mammals from underwater

noise

1 – Minor

5 – Likely 5 – Low Less than minor


marine mammals from helicopter

noise

1 – Minor

4 – Possible

4 – Low Less than minor


fish

1 – Minor 3 - Unlikely 3 – Low Less than minor


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Noise and vibrations – effects on

cephalopods

0 – Negligible 3 – Unlikely 0 – Negligible Negligible


seabirds

1 – Minor 5 – Likely 5 – Low Less than minor


zooplankton

0 - Negligible 3 – Unlikely 0 - Negligible Negligible

Contingent activities – effects from

explosives on benthic communities


Contingent activities – effects of

explosives on marine mammals


Contingent activities – effects of

explosives on fish


Other

Effects on Existing Interests -

commercial fishing

0 – Negligible 6 – Certain 0 – Negligible Negligible

Human health 0 – Negligible 1 – Remote 0 – Negligible Negligible

Effects outside the EEZ 0 – Negligible 1 – Remote 0 – Negligible Negligible

Cumulative Effects

Discharge of harmful substances 0 – Negligible 1 – Remote 0 – Negligible Negligible

Maritime Traffic - Noise & Vibration 0 – Negligible 1 – Remote 0 – Negligible Negligible

Section 7.3 of the IA describes the environmental risk assessment for the proposed discharge

activities and the Chemical Hazard Assessment and Risk Management5 (CHARM) and Non-CHARM

model assessment methodologies used. Both methodologies model a gradient of effects at set

distances from a point of discharge and produce a risk quotient (RQ) based on predicted

environmental concentration (PEC) and predicted no effect concentration (PNEC).

The IA states that the ERA uses the best available information and deals with the uncertainty in

regards to the specific details of the discharge characteristics by adopting worst-case assumptions

which produces worst-case results for each discharge that is assessed.

With the exception of NF-6 (cement additive), the environmental risk assessment’s modelling (Table

38 of the IA) provides at less than 500m from the point of discharge, the magnitude of the worst-case

scenario of potential effects from the discharge of BE-9, residual hydrocarbons or Erifon HD would be

no more than negligible. At 1,784m from the point of discharge, the modelling of the worst-case

5 Chemical Hazard Assessment and Risk Management Model CHARM-User-Guide-Version-1-5.pdf (eosca.eu)

https://eosca.eu/wp-content/uploads/2018/08/CHARM-User-Guide-Version-1-5.pdf


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scenario for the discharge of NF-6 (Cement additive) provides the potential effects as being negligible.

This indicates that the marine environment beyond 1,784m of the discharge could be affected in a

small but measurable way. The IA states that any small volumes of NF-6 that remain in the water

column at 1,784m from the point of discharge (MODU or WIV), would quickly disperse to below

ecotoxic concentrations.

The IA states that all predicted potential ecotoxic effects will be temporary and at worst, could last for

a number of months in the marine environment and that any effects that do arise will be sporadically

distributed along a spatial and temporal gradient from the end of the flowline, wellhead, or MODU/

WIV. Once decommissioning operations stop, MBIE expects the gradient of effects in the water

column, will quickly disperse as discharges will no longer occur. The IA notes that the gradient of

effects that will likely occur in the benthic environment will take longer to disperse and will be linked

with the rate of recolonisation of the sediment around the disturbed areas. The ERA results provided

within the IA are summarised in Table 2 below.

Table 2: IA’s proposed discharge activities risk quotients & the magnitude of environmental effects

Planned Marine Discharge Consent

Activities

Risk quotient Predicted magnitude of

environmental effects

Discharge of Biocide Inhibited Seawater RQ = 0.014 Negligible

Discharge of Residual Hydrocarbons RW = 6.1 Almost Negligible

Discharge of BOP Fluids RQ = 0.068 Negligible

Discharge of Cement Additive RQ = 0.21 Negligible

Statutory decision-making framework

The basis for decision-making under the EEZ Act was recently addressed by the Supreme Court6.

The role of section 10 was summarised by Glazebrook J as follows7:

As a purpose provision, section 10 provides the basis for the purposive interpretation of the other

sections of the EEZ Act. It also, however, provides an overarching guiding framework for decision-

making under the Act and, to this extent has substantive or operative force.

The EEZ Act Purpose

The purpose of the EEZ Act is set out in section 10 of the EEZ Act:

“(1) The purpose of this Act is—

6 Trans-Tasman Resources Limited v Taranaki-Whanganui Conservation Board and Others [2021] NZSC 127. 7 Trans-Tasman Resources Limited v Taranaki-Whanganui Conservation Board and Others [2021] NZSC 127.

at para 240.


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(a) to promote the sustainable management of the natural resources of the exclusive economic

zone and the continental shelf; and

(b) in relation to the exclusive economic zone, the continental shelf, and the waters above the

continental shelf beyond the outer limits of the exclusive economic zone, to protect the

environment from pollution by regulating or prohibiting the discharge of harmful substances

and the dumping or incineration of waste or other matter.

(2) In this Act, sustainable management means managing the use, development, and protection of

natural resources in a way, or at a rate, that enables people to provide for their economic well-being

while —

(a) sustaining the potential of natural resources (excluding minerals) to meet the reasonably

foreseeable needs of future generations; and

(b) safeguarding the life-supporting capacity of the environment; and

(c) avoiding, remedying, or mitigating any adverse effects of activities on the environment.

(3) In order to achieve the purpose, decision-makers must—

(a) take into account decision-making criteria specified in relation to particular decisions; and

(b) apply the information principles to the development of regulations and the consideration of

applications for marine consent.”

The Supreme Court has established a three-step test for decision-makers when assessing

applications for marine discharge or dumping consents. This is expressed as follows8:

(a) Is the decision-maker satisfied that there will be no material harm caused by the discharge or

dumping? If yes, then step (c) must be undertaken. If not. Then step (b) must be undertaken.

(b) Is the decision-maker satisfied that conditions can be imposed that mean:

(i) material harm will be avoided;

(ii) any harm will be mitigated so that the harm is no longer material; or

(iii) any harm will be remedied within a reasonable timeframe so that, taking into account the

whole period harm subsists, overall the harm is not material?

If not, the consent must be declined. If yes, then step (c) must be undertaken.

(c) If (a) or (b) is answered in the affirmative, the decision-maker should perform a balancing

exercise taking into account all the relevant factors under s 59, in light of s 10(1)(a), to determine

whether the consent should be granted.

The decision-making criteria in section 59 of the EEZ Act apply to any application for a marine

consent. For a marine discharge consent, however, section 59(2A)(a) directs the Board to specifically

8 Trans-Tasman Resources Limited v Taranaki-Whanganui Conservation Board and Others [2021] NZSC 127 at para 5.


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exclude the matters described in section 59(2)(c) from its considerations, which relates to the effects

on human health that may arise from effects on the environment. Section 59(2A)(b) instead directs the

Board to take into account the effects on human health of the discharge of harmful substances, if

consent is granted.

Section 10 also directs the Board to take into account the decision-making criteria in section 60, and to

apply the information principles set out in section 61 of the EEZ Act. The relevant sections of the EEZ

Act are provided in Appendix 2. Section 61(1)(b) of the EEZ Act requires the Board to base its

decisions on the best available information. Section 61(5) defines that, for the purposes of section 61,

best available information means the best information that, in the particular circumstances, is available

without unreasonable cost, effort, or time. Further, section 61(1)(a) requires the Board to make full

use of its powers to request further information form the applicant, obtain advice, and commission a

review or report.

Under section 54 of the EEZ Act the Board may request that the applicant provide further information

relating to an application, and under section 56 it may:

a. commission an independent review of the applicant’s IA;

b. seek advice or information from any person on any aspects of the application or proposed

activity; and

c. commission any person to provide a report on any aspects of the application or the proposed

activity.

Under section 61(2) of the EEZ Act, if the information available is uncertain or inadequate, the Board

must favour caution and environmental protection. As MBIE has applied for a marine discharge

consent, section 61(4)(a)(ii) applies to the proposed discharge activities, and provides that if the

information available is uncertain or inadequate, the Board is not able to consider, whether taking an

adaptive management approach would allow these activities to be undertaken.

Conditions of Consent

Section 59(2)(j) of the EEZ Act requires the Board to take into account the extent to which imposing

conditions under section 63 might avoid, remedy, or mitigate the adverse effects of the activity. Under

section 63(1) the Board may grant a marine consent on any condition that it considers appropriate to

deal with adverse effects of the activity authorised by the consent on the environment or existing

interests. Section 63(2) gives examples of the types of condition which may be imposed, and sections

65 to 67 (bonds, monitoring, observers) give further detail regarding the type of conditions outlined in

section 63(2).

Under section 64(1AA)(b), section 64 (adaptive management approach) does not apply to a marine

discharge consent application. Conditions under 63(2)(b), which together amount or contribute to an

adaptive management approach, can therefore not be imposed, if the marine discharge consent was

to be granted.


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Sections 63(3) and 63(4) of the EEZ Act give further detail of conditions which cannot be imposed on

consents. Section 63(1) provides the Board with a very wide scope to impose conditions on marine

consents and marine discharge consents, including those specified in section 63(2). However, there

are two restrictions specified in sections 63(3) and 63(4) that the Board will need to be aware of which

respectively prohibit:

a. the imposition of conditions which are inconsistent with the EEZ Act or any regulations (section

63(3)); or

b. the imposition of a condition to deal with an effect if the condition would conflict with a measure

required in relation to the activity by another Marine Management Regime (MMR), or the Health

and Safety at Work Act 2015 (section 63(4)).

In addition to the conditions which the Board may impose, if consent is to be granted, other conditions

volunteered by the applicant, including those that may be outside those that the Board may impose

under the EEZ Act, may also be imposed and become enforceable by the EPA. Such conditions are

often referred to as ‘Augier’ conditions. The prohibitions in section 63(3) and 63(4), however, still apply

to Augier conditions.

MBIE has included a set of proffered consent conditions in section 9 and appendix A of the IA.

Emergency Spill Response Plan

Under regulation 24 of the D&D Regulations, the owner of an offshore installation must not operate the

offshore installation without an Emergency Spill Response Plan (ESRP) approved by the EPA. Under

regulation 24(3), the ESRP must contain emergency spill response procedures for any ecotoxic, or

very ecotoxic substances held on-board in volumes exceeding 20 litres, and for any other substances

covered by regulation 4(a), where substances are held in volumes exceeding 100 litres. Under

regulation 24(4)(a), these procedures must include:

(i) a list of harmful substances stored on the offshore installation;

(ii) the maximum volumes of the substance likely to be stored on the offshore installation; and

(iii) a description of the processes and activities that present a risk of a spill of a substance.

The list of harmful substances to be held on a MODU, as described above, will need to be provided to

the EPA, in accordance with the ESRP requirements under regulation 24(5) of the D&D Regulations at

least two months before the date on which operations are due to begin.

Hazardous Substances & New Organisms Act 1996

The hazard classification under the Hazardous Substances and New Organisms Act 1996 (HSNO

Act) for substances that come within the definition of ‘harmful substances’ under the EEZ Act is

relevant to assess their discharge related effects on the environment. The substance hazard

properties, together with the facts establishing the existence of any potential exposure route to

ecological receptors, determine the level of risk posed by the substance.


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The relevant statutory provisions have the effect that ‘harmful substances’ under the EEZ Act

correspond to substances that are ecotoxic to the aquatic environment under the HSNO Act. Due to

EPA notices, this means that some seventh revised edition of the United Nations Globally Harmonised

System of Classification and Labelling of Chemicals (GHS 7) classification categories for substances

that are ‘hazardous to the aquatic environment’, apply.

Purpose

The purpose of the HSNO Act as set out in section 4 is:

“to protect the environment, and the health and safety of people and communities, by preventing or

managing the adverse effects of hazardous substances and new organisms.”

HSNO Approvals

Under section 28 of the HSNO Act an importer or manufacturer of a hazardous substance must obtain

approval(s) for the substance under the HSNO Act. Approval must be obtained prior to the substance

being imported or manufactured.

Any harmful substance to be used as part of MBIE’s decommissioning programme, or to be stored on-

board a MODU while it carries out the decommissioning programme, will need to hold an existing

approval under the HSNO Act. Maritime New Zealand is responsible for ensuring that the provisions of

the HSNO Act are complied with in respect to ships within the EEZ.

2020 Hazard Classification Notice

The majority of the hazardous substance rules for which the EPA is responsible for are set in EPA

Notices. This includes rules for environmental controls and hazardous substances disposal controls.

The Hazardous Substance (Hazard Classification) Notice 2020 (Hazard Classification Notice)

classifies substances based on the GHS 7.

Schedule 3 of the Hazard Classification Notice shows the correlations between the previous HSNO

classifications for aquatic ecotoxicity, and the equivalent GHS classifications.

The GHS 7 classifications most relevant to this application are those that are hazardous to the aquatic

environment. These classifications are:

a. hazardous to the aquatic environment acute Category 1

b. hazardous to the aquatic environment chronic Category 1

c. hazardous to the aquatic environment chronic Category 2

d. hazardous to the aquatic environment chronic Category 3

e. hazardous to the aquatic environment chronic Category 4

The HSNO Act and classification system uses the term ‘hazardous substance’ when referring to

substances that are ecotoxic to aquatic organisms. The EEZ Act, and associated regulations, uses the


17

term ‘harmful substance’ when referring to oils and hazardous substances that are ecotoxic to aquatic

organisms.

Due to a savings provision under clause 16 of the Hazard Classification Notice, all references to the

Hazardous Substances (Minimum Degrees of Hazard) Notice 2017 under the EEZ Act are to be

treated as a reference to the new Hazard Classification Notice. Accordingly, all of the above listed

GHS7 classifications are considered hazardous to the aquatic environment under regulation 16(1) of

the D&D Regulations and the most appropriate approach to referring to hazardous substances

according to their aquatic ecotoxicity in New Zealand is to reference the Hazard Classification Notice.

Key Issues

Introduction

After reviewing the application documents and the EPA commissioned expert advice, I consider that

there are seven ‘key’ issues associated with the proposal, namely:

a. Ecological receptors & seasonal sensitivity

b. Biosecurity risk management

c. Seabed disturbance

d. Well plugging & abandonment

e. Discharge uncertainties

f. Existing interests & Te Ao Māori

g. Environmental monitoring

Ecological Receptors & Seasonal Sensitivity

Seasonal Sensitivity:

The seasonal sensitivity of various ecological receptors varies throughout the year and could be

considered further than what is presented in the IA. The timing of when the proposed activities occur

could change the effects on certain ecological receptors and could even delay the recovery of benthic

communities. The Board may wish to carefully consider whether it requires further information around

this in the context of to better assess the effects of the proposed activities.

Pattle Delamore Partners (PDP) reviewed the IA and identified potential information gaps in terms of

considering the temporal variation in the sensitivity of various ecological receptors as a consequence

of seasonal effects. Marine mammal migration, breeding periods, or the presence of juvenile animals

and their varied susceptibility to disturbance does not appear to be considered in the IA.

The IA includes a decommissioning plan (Appendix D). This plan includes an indicative timeline for

the project that reflects the preferred seasonal aspects for the proposed works. It appears those

seasonal elements for the various activities have not informed the IA regarding potential effects on


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marine mammals, fish and cephalopods, seabirds and benthic biological communities or the overall

environmental risk assessment.

However, PDP have noted there are aspects within the IA, that tend to minimise the significance of

some environmental impacts and while it is unclear in the IA, this may be the result of taking seasonal

aspects or other factors into consideration without explicitly detailing this aspect. PDP state this is

particularly noticeable when it comes to the discharge of harmful substances and the potential for

cumulative impacts resulting from discharges of harmful substances combined with seabed

disturbance (this topic is discussed in paragraphs 162-163 below).

Benthic Recovery:

One notable aspect of seasonal sensitivity that does not appear to have been considered within the IA, is

the potential for variation in the effects on benthic biological communities resulting from seabed

disturbance.

PDP note that the consideration of variations in larval supply and the varied opportunities for recruitment

or immigration of organisms from nearby habitats as a result of seabed disturbance appears to be

lacking. Given the largest effects of the proposal will impact the benthic environment, PDP suggests

further information would be useful in regards to the likely rates of recolonisation and benthic biological

community recovery and the processes involved.

The Board may wish to seek further information to consider the variation in receptor sensitivity as a

result of seasonal factors and consider the timing of the proposed activities might avoid or minimise

adverse environmental effects and enable healthy benthic recovery. If certain timing of some activities

was found to reduce or minimise adverse effects, and the Board was to grant the application, those

issues could potentially be addressed in conditions of consent.

Potential Receptors with Protected Status:

There is the possibility that the proposed activities may have adverse effects on species protected

under the Marine Mammals Protection Act 1978 and the Wildlife Act 1953. The Board will need to

carefully assess if it has the best available information regarding effects on these species and the

weight it wishes to assign to its findings in this area.

On 3 September 2021, the Department of Conservation (DoC) responded to an EPA request for

information under section 56 of the EEZ Act. In this response, DoC noted that it was considering

making a submission on the notified marine consent notification. In particular, it is interested in

whether the decommissioning activities may have adverse effects on species protected by the Marine

Mammals Protection Act 1978 and the Wildlife Act 1953.

PDP observed that while they did not necessarily disagree with the magnitude of impacts outlined in

the IA from a purely ecological viewpoint. However, the fully protected status of some potential

receptors suggests that, any adverse effects on individuals might require greater weighting than what

appears to have been assigned in the IA.


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I agree with PDP’s observation and note a submission from the DoC may include information that may

help the Board consider this aspect further. If DoC decides not to make a submission, the Board could

still seek additional information from DoC if it wished to.

Biosecurity Risk Management

The biosecurity risks associated with bringing equipment and vessels into the country from overseas are

discussed in section 3.4.1 of the IA.

Having reviewed this information, PDP has noted there are unattended biosecurity risks regarding the

use of equipment without the assurance of proper cleaning protocols.

Further information was requested directly from Biosecurity New Zealand under section 56 of the Act.

However, only a brief response was received from Biosecurity New Zealand, which simply outlined that

there were no biosecurity issues of concern to them, other than the usual border requirements for any

international vessels or structures arriving into NZ that would be associated with the proposed activities.

While the biosecurity risks posed by vessels coming into New Zealand may be avoided or mitigated by

the requirements of the Craft Risk Management Standards, Import Health Standards and various other

requirements from Biosecurity New Zealand. There remains a biosecurity risk regarding the use of

equipment, such as ROVs, brought in from other areas. Lack of appropriate management may increase

the risk of the introducing unwanted organisms and the spread of organisms between areas within the

country.

Should the Board be of a mind to grant the marine consent application, the Board may choose to

prescribe conditions that require the preparation of, and adherence to an approved biosecurity

management plan to address the biosecurity risks identified regarding the equipment associated with the

proposed decommissioning programme.

Seabed Disturbance

Section 4.2.8 and Section 7.2.3.2.3 of the IA describes that during the proposed decommissioning

activities, seabed disturbance in the form of sediment suspension and deposition is a certain effect

due to the silty clay substrate and will be a common consequence of placing, moving or removing

equipment and SSI from the seabed. The extent of the effects from seabed disturbance is discussed

within Section 7.2.3.2 of the IA.

The extent of the effects from seabed disturbance will be significantly different if MBIE uses a WIV

instead of a MODU. The adequacy of the retrieval methods used to recover the subsea infrastructure

is also important to limit the amount of seabed disturbance. Both of these topics are discussed in the

following paragraphs.

Retrieval Methods:

Intecsea has reviewed the retrieval methods proposed for the recovery of the subsea infrastructure

and comment that the methods are in line with industry standards. They do however note some

concerns and observations that are relevant to seabed disturbance.


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Due to the pre-charge of gas in the MWA and the risk of the buoyancy cans that make up the arches

becoming detached form the hold back rigging, Intecsea have identified the sinking of the MWA

(referred to as Option 3 in the IA) is the preferrable retrieval option proposed. Although there is the

potential for more seabed disturbance caused by the landing of the arches onto the seabed, in terms

of best industry practice, Intecsea notes that this option would be the safest of the options.

Intecsea has concerns with the proposed “Miscellaneous Equipment” removal methodology being

applied to the concrete “crossing” structure located where the Pateke-3H umbilical/Pateke-4H flowline

cross. During the overall process of retrieving the concrete crossing structure, the IA provides that a

frame may be placed on the seabed so that the concrete crossing structure can be lifted on to the

frame and then recovered together. This would reduce the risk of the concrete crossing structure

breaking during its recovery. Intecsea has noted that, in their experience, the removal of aged

concrete structures may be problematic due to the risk of the structure breaking up before it can be

recovered.

If this concrete crossing structure were to break apart, this would increase the level of seabed

disturbance and require additional retrieval activities to collect the broken concrete segments of the

structure which could provide their own seabed disturbance. In the IA, mitigations to decrease the

effects from a break up event are described and include the use of equipment such as a crane grab

and a basket to recover individual pieces as far as reasonably practicable. Intecsea’s opinion and

experience is that the use of such tools would also cause additional disturbance to the seabed.

I consider that the applicant has appropriately assessed the degree to which the seabed is likely to be

disturbed, and the associated adverse effects on the environment. However, the Board will need to

decide whether further information from MBIE is required in respect of the concerns that have been

raised by Intecsea.

WIV or MODU:

Section 2.3.9. of the IA describes the activities and methodology in regards to the removal of the

various subsea equipment. The proposed installation of a semi-submersible MODU that uses anchors

array would disturb the seabed and, as such, MBIE is applying for a marine consent for the installation

of such a MODU. The use of a dynamic positioning (DP) vessel, including a WIV, does not require

marine consent under section 20 of the EEZ Act as a DP vessel would not require the placement of

anchors on the seabed thereby avoiding seabed disturbance.

Section 7.2.3.2 of the IA outlines that the MODU option would require eight placements with 12

anchors. This proposed activity easily represents the largest cause of potential seabed disturbance

when compared to the other proposed activities within this application. Based on a worst-case

scenario, the IA’s estimates the total MODU related seabed disturbance would effect a total area of

123,800m2. If MBIE were to use a WIV rather than a MODU no such seabed disturbance would occur.

On the other hand, Intecsea note that the more technically conservative option is for a rig-based well

abandonment with a MODU, as discussed in the following section of this Key Issues Report.


21

Well Plugging & Abandonment

Consent is required for the plugging and abandonment of wells under section 20 of the EEZ Act.

There are risks of adverse effects associated with this activity not being done properly to which the

Board will need to give close consideration.

The Board can consider these matters as part of its consideration of marine management regimes.

The Board will likely find understanding health and safety requirements and, in particular, the Health

and Safety at Work (Petroleum Exploration and Extraction) Regulations 2016 to be particularly

relevant as a starting point as these requirements could potentially avoid, remedy or mitigate adverse

effects on the environment or existing interests resulting from the any activities associated with the

plugging and abandonment or wells. Further explanation can be found in the section 56 further

information response from WorkSafe and Maritime New Zealand.

WIV or MODU:

From a wider best industry practice point of view, Intecsea note a MODU based approach provides

optimal operational flexibility, allowing for all available contingency options to be an available and

viable option should the planned well plug & abandonment operations experience unforeseen events.

Intecsea note that thru-tubing well plug & abandonment with a WIV, requires assurance of annular

cement and casing integrity. Should any of the key required well barriers be found to be missing or

inadequate, the requirement to remove the completion and /or casing tubulars may be required to

achieve safe wellbore isolation. Verified well barriers (established based on industry best practices)

are critical to provide long term environmental protection and particularly important when the wellhead

will be severed as the final step of the well plug & abandonment process. Should a well leak occur

post wellhead severance, the ability to remedy the situation would not be straight forward and would

result in negative environmental impact. Due to the remote location of the Tui Field internationally,

should a rig-less approach (WIV) fail to achieve safe wellbore isolation, in the planned operational

window, there is unlikely to be a drilling unit available nearby for a short turn around call off.

Well regulatory requirements & internationally accepted good practice:

WorkSafe and Maritime New Zealand provided information in response to an EPA request for

information under section 56 of the EEZ Act9. The information provided by both regulatory authorities

provides insight into how the risk of unplanned loss of well control is managed under their respective

regulatory regimes and is summarised in the following paragraphs.

WorkSafe New Zealand is typically the relevant authority to ensure that wells have been properly

designed, constructed and operated in a way that reduces the likelihood of a well blowout to as low as

reasonably practicable. For an offshore installation (such as a MODU), this is primarily demonstrated

by way of a Safety Case that is submitted to WorkSafe NZ for approval. Should a WIV be used for the

plugging and abandonment activities instead of an offshore installation however, it is important to note

9 Letter from WorkSafe to the EPA dated 27 August 2021 & Letter from Maritime NZ to the EPA dated 07 September 2021.


22

that the regulatory responsibilities under the Health and Safety at Work Act 2015 would fall under the

jurisdiction of Maritime New Zealand (MNZ) rather than WorkSafe.

The WorkSafe Regulations do not include prescriptive well abandonment requirements, but instead

require wells to be designed for safe abandonment and in line with internationally accepted good

practice, including incorporating continual improvement in practices and technology. Intecsea agree

with MBIE’s proposal to follow the industry recognized Oil and Gas UK (OGUK) Well

Decommissioning Guidelines – Issue 6, June 2018. Intecsea consider these guidelines reflect the

latest industry approach and encourage innovation and efficiency whilst providing a robust framework

for the risk based decision-making process that should accompany any well decommissioning activity.

Intecsea note that the IA states that the well abandonment design will be approved by an independent

well examiner in accordance with WorkSafe requirements. Well Examination under the Health and

Safety at Work (Petroleum Exploration and Extraction) Regulations 2016 (PEE regulations) focuses

on ensuring that the proposed designs, and their execution, are completed while meeting defined Well

and Environmentally Critical Elements (WECEs). Intecsea note that the Well Examination is

considered a critical service which aids in ensuring that abandonment operations are carried out

following “as low as reasonability practical” (ALARP) principles.

Further information could also be sought from MNZ to clarify whether a WIV’s H&S regulatory

requirements would also include the need for independent well examination and the safe

abandonment in line with internationally accepted good practice (as is required under WorkSafe’s PEE

regulations for a MODU).

Previously plugged & abandoned exploration wells:

Section 2.4.6 of the IA states that: “The three exploration wells have previously been plugged and

abandoned after drilling and only require the wellheads, casing and conductor to be removed 3 m

below the seabed. This work may be completed with the remaining P&A work, or during the retrieval of

the SSI.”

Intecsea has reviewed this statement within the IA and agree that exploration wells Tieke-1 and

Amokura-1, meet the above statement, based on the OGUK Well Decommissioning Guidelines –

Issue 6, June 2018. In doing so, Intecsea have noted concern regarding the third exploration well, TUI

SW-2P/2 (TUI-SW2). Intecsea is satisfied that the first plug meets the above requirement and provides

reservoir isolation but does not consider the second plug meets this requirement under the current

OGUK Well Decommissioning Guidelines – Issue 6, June 2018. Accordingly, Intecsea is uncertain

whether this lack of an adequate second barrier presents a long-term potential leak path for well fluids.

Tui-SW2 is understood to have a reservoir isolation barrier (referred to as “Plug 1”) that has been

placed adjacent to good 9 5/8” annular cement. However, the second plug (“Plug 2”), has not been set

across annular cement and therefore does not present a well barrier. Traditionally, industry best

practice has been to place an 800ft barrier to achieve 200ft of “good” cement as a combination barrier,

however the current OGUK Well Decommissioning Guidelines – Issue 6, June 2018 state:


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“When a combination barrier is chosen to replace two barriers, it should have:

- A cement column of typically a minimum 200 ft MD of good cement, which is considered to

constitute such a permanent barrier.

- Typically, 200 ft MD of good cement above the zone with flow potential.

- The internal cement plugs adjacent to the annular good cement over a cumulative distance of

200 ft MD of overlap.”

Should the Board wish to obtain certainty in this regard, further information could be sought from MBIE

to demonstrates that the proposed approach has been assessed to be ALARP in terms of risk and that

the wells will be abandoned in accordance with the OGUK Well Decommissioning Guidelines.

Intecsea has also observed that MBIE does not appear be proposing any shallow environmental

cement plugs for the plug and abandonment of any of the subject wells. Intecsea acknowledge this

requirement is not explicitly stated in the OGUK Well Decommissioning Guidelines, but considers it to

be industry best practice, particularly in circumstances where the wellhead is to be severed during the

final well operation.

Intecsea notes this provides uncertainty as to whether the lack of shallow barriers will present a long-

term potential leak path for well fluids or not, and suggests, that, should the BOI wish to obtain

certainty in this regard, further information could be sought from MBIE to demonstrates that the

proposed approach has been assessed to be ALARP in terms of risk.

Oil pollution prevention, spill response & liability insurance:

Part 131 of the Marine Protection Rules provides for an offshore installations’ certification against the

requirements in Annex I of MARPOL. MNZ accepts a valid International Oil Pollution Prevention

(IOPP) Certificate issued by, or on behalf of the flag state when exercising port state control over a

ship. However, New Zealand has exclusive jurisdiction over the IOPP in the case of an offshore

installation.

MNZ requires offshore installations to have liability insurance or other financial guarantee under Part

102 of the Marine Protection Rules and associated Maritime Transport Act (MTA) provisions.

Regulated offshore installations must hold a current certificate of insurance evidencing cover for

liability for clean-up costs and pollution damage to property arising from the discharge of a harmful

substance or dumping of any waste or other matter under the MTA.

To address the possibility that primary safety mechanisms fail or there is an accident resulting in a spill

of hydrocarbons into the marine environment, operators of an offshore installation must also have the

associated Tier 1 oil spill response capability, an Oil Spill Contingency Plan (OSCP) and a Well

Control Contingency Plan (WCCP) approved by Maritime New Zealand.

Tier 1 oil spill response capability is site specific and made for a response to a worst case operational

spill, or to provide an initial response to a larger spill incident. An approved OSCP requires the

operator to minimise the risk of an accidental oil spill and details emergency response plans in place in


24

case a spill does occur. A WCCP requires the operator to demonstrate that it has prepared for a

worst-case scenario and that it has the means to shut-in the well – stopping all hydrocarbon flow to the

environment as quickly as possible - no matter how unlikely it might be.

Part 130A of the Marine Protection Rules requires both foreign and NZ flagged ships (other than oil

tankers, that are 400 GT or above) to have an approved OSCP. Under Marine Protection Rules Part

130A, foreign ships flagged to a State party to MARPOL must carry onboard the ship a current

shipboard oil pollution emergency plan approved by their administration. In addition, foreign ships

flagged to a State that is not party to MARPOL must instead carry onboard the ship an emergency

plan for responding to oil pollution incidents and containing and cleaning up oil spills from the ship,

together with evidence that the emergency plan complies with the standards prescribed by Regulation

37 of Annex I of MARPOL. These documents are confirmed by MNZ once the vessel arrives in a New

Zealand port through a port state control inspection.

In their report, Intecsea noted that the regulatory documents and plans discussed above, such as a

safety case, an ESRP and an OSCP are essential for safeguarding the environment surrounding the

Tui field. Intecsea also noted that it is important that these documents are developed and adhered to

for the proposed decommissioning activities and suggest, that if the Board was to grant the

application, conditions could be prescribed so that the EPA are able to review and comment on these

documents.

Section 63(4) of the EEZ Act restricts the imposition of conditions to deal with an effect, if the condition

would conflict with a measure required in relation to the activity by another MMR, or the Health and

Safety at Work Act 2015.

Considering the measures required under WorkSafe and MNZ, and noting section 63(4) of the EEZ

Act, the Board may wish to turn its mind to whether there are any other measures that are likely to be

necessary to further reduce the likelihood or consequence of a hydrocarbon spill. In this regard,

should the Board wish to, further information could be sought from MBIE, WorkSafe or MNZ to provide

additional certainty regarding the risk of long-term hydrocarbon leaks from the wells that are to be

plugged and/or abandoned.

Discharge Uncertainties

CHARM & Non-CHARM assessment & GHS classification:

Section 7.3 provides an ERA for the proposed discharge of harmful substances and applies a CHARM

and Non-CHARM assessment methodology. Both are suitable environmental risk assessment

methodologies for considering the discharge of harmful substances however they rely on reliable input

data and suitable parameters to frame the worst-case scenario.

From an ecotoxicology perspective, COPE Environmental Consultancy Limited (COPE) has provided

a review of the ERA based on the information provided in section 7.3, Appendix B (Safety Data sheets

(SDS)) and Appendix J of the IA. COPE also utilised international databases such as NZ Chemical

Classification and Information Database (CCID) and the European Chemical Agency (ECHA).


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The review by COPE applied a precautionary approach where there is uncertainty regarding the

available data or where more conservative or reliable data is available. Accordingly, the review by COPE

has found different GHS7 aquatic toxicity classifications could have been used for some of the harmful

substances in MBIE’s ERA.

COPE’s review also notes some aspects of the approach and inputs to the risk assessment for BE-9

and Erifon HD, Tui crude oil and NF-6 contribute to an underestimation of the environmental risks. These

observations are discussed in the following paragraphs.

COPE’s review does not stipulate the degree or significance of the classification discrepancies might

have in terms of environmental risk. Should the Board wish to resolve the uncertainty in this regard, I

recommend further information is requested from MBIE to address the observations made by COPE.

Residual hydrocarbon discharges:

Prior to the disconnection and removal of the FPSO, the flowlines and risers were flushed of

hydrocarbons. However, it is possible that a small residual amount of hydrocarbons may still remain

within the flowlines and risers, and this may be discharged during the removal of the lines. Section

2.5.2 of the IA outlines the environmental risk posed by any residual Tui crude oil being discharged

from the flowlines and risers. The IA has assessed the predicted magnitude of environmental effects

from the discharge of residual Tui crude oil to be almost negligible.

Based on their understanding of industry practice regarding the flushing of flowlines, Intecsea

considers all of MBIE’s estimated volumes for the residual hydrocarbons are very conservative.

Intecsea note that MBIE’s estimated volume calculations originate from a conservative estimate of the

percentage of crude oil that may have been in the pipeline prior to flushing (0.7-3.2 barrels). Given that

the flowlines were flushed by experienced contractors in line with best practice, Intecsea considers

MBIE’s subsequent calculations regarding the estimated volume of residual hydrocarbons to be

discharged is an overestimation by a factor of 10.

Applying a worst-case scenario principle, MBIE based their ERA on the longest flowline (Pateke-3H).

MBIE also used a non-CHARM method and a conservative estimate of the volume of hydrocarbons

remaining in that flowline. COPE’s review noted there are other flowlines that residual hydrocarbons

may be discharged from and a total estimated volume of all flowlines could have been used instead to

determine the combined risk of Amokura, Pateke 4H and Tui 2H rather than the single volume based

on a discharge from the longest flowline (Pateke-3H). MBIE used the estimated volume of 116L for

which to base the discharge residual hydrocarbons from Pateke-3H, whereas MBIE’s estimated total

volume of residual hydrocarbons that may be discharged from all the production flowlines is ~171 L. A

discharge of the total volume (171 L) would represent the worst-case scenario on which to base the

risk assessment of the discharge of residual hydrocarbons.

Intecsea also observe that while sections of the IA suggest the umbilicals have been flushed and left

charged with Transaqua Ht2, it is not clear whether this applies to all of the hydraulic flying leads

(specifically, the hydraulic flying leads that run from the distribution units to the end users).


26

Accordingly, there may be potential for hydrocarbons to be discharged when some of the hydraulic

flying leads are cut and does not appear to have been considered within the IA.

I recommend clarification is sought from MBIE, as to whether the hydraulic flying leads from the

distribution units to the end users have been flushed and left with Transaqua Ht2 and their potential for

discharging hydrocarbons when cut.

I also recommend further information is requested from MBIE to address the observations made by

COPE.

BOP hydraulic fluid discharges:

Section 2.5.3 outlines that, during the well plugging and abandonment activities, the BOP needs to be

periodically tested to ensure that all hydraulic valve systems are in proper working order. BOP

hydraulic fluids will be discharged into the environment when the BOP system is tested and in the

event that the BOP is ever triggered.

The IA provides the BOP hydraulic fluids include a proportion of the harmful substance product called

Erifon HD 603 HP No Dye (Erifon HD). Section 7.3.2.3.1 of the IA classifies Erifon HD as being

‘chronic category 1’ for aquatic toxicity. Using mixture rules for GHS classifications, COPE’s review

classifies Erifon HD as acute and chronic category 1 in terms of aquatic toxicity. The IA has assessed

the predicted magnitude of environmental effects from the discharge of Erifon HD to be negligible.

The environmental risks posed by Erifon HD is assessed in the IA using a Non-CHARM method for a

continuous discharge of 40L. COPE highlights that the substance will bioaccumulate in organisms.

COPE also considers an assessment of the total volume of 720 L of product proposed to be

discharged would have been more appropriate in order to consider a worst-case scenario.

COPE also notes the lowest endpoint value of 0.00349 mg/L for fish should have been used instead of

the lowest endpoint of 0.037 mg/L for the crustacean Daphnia. Both values are from the Canadian

Domestic Substance List but the IA does not make it clear why 0.037 mg/L was used. COPE notes

that the choice of lowest endpoint value may result in an underestimation of the environmental risks

associated with the proposed discharge of Erifon HD.

I recommend further information is requested from MBIE to address the observations made by COPE.

Cement additive discharges:

The IA outlines that cementing operations will all be undertaken from either a MODU or a WIV and the

majority of the cement will be used for setting plugs within the well bores. The cement plugs are likely

to come into contact with seawater at the point where the well is cut off, some three metres below the

seabed surface, at which time the cement plug would have largely dried and hardened and it would be

buried by infilling of seabed sediments. The additive in the cement mixture is a cement defoaming

agent called NF-6. The actual diffuse discharge of NF-6 is likely to be very minor.


27

Intecsea observed that a BOP and riser provides a closed loop system which significantly lowers the

risk on the surrounding environment but noted that section 2.5.4 of the IA is not clear as to whether a

BOP and riser would be in place for how many of the cementing operations or not.

The IA describes there will also be a discharge of cement contaminated wash water following

cementing operations and that wash water will contain very small quantities of the NF-6 additive. To

limit the amount of cement contaminate within the wash water and therefore NF-6, Intecsea

recommend that the cement chemical usage should be based on ensuring that the minimum

verification requirements of the OGUK Well Decommissioning Guidelines are met.

Section 2.4.5 of the IA states, “each cement plug will be carefully calculated to ensure the minimum

volumes remain onboard the MODU/WIV once the cementing is completed”. Intecsea noted this

wording and observed that ensuring minimum volumes remain onboard the vessel once the cementing

operations have been completed, does not necessarily result in less harmful substances being

discharged into the marine environment. The emphasis should instead be on achieving an accurate

amount of the required volume of mixed cement slurry for each plug, in line with best practice.

Section 7.3.2.4.1 of the IA classified the aquatic toxicity of the NF-6 product as ‘chronic category 2’.

Taking a precautionary approach, COPE also classified the NF-6 product as ‘chronic category 2’ in

terms of its aquatic toxicity. COPE notes that the lowest endpoint for NF-6 is an LC5010 of 7.3 mg/L

(acute value) for the fish Misgurnus, and that it is not persistent (67% degradation at 21 days). COPE

also notes there is no known information regarding bioaccumulative potential.

COPE also observed that it is not clear whether CHARM or a non-CHARM method was applied to the

assessment of NF-6 within MBIE’s ERA. Section 7.3.2.4.2 of the IA outlines that the CHARM method

is used to assess the risk of the proposed discharge of NF-6 and the excel sheet ‘harmful substance

data redacted’ within Appendix J also refers to the CHARM method. However, Table 38 of the IA and

the excel sheet ‘non-CHARM batchwise’ within Appendix J state that the non-CHARM method is used.

Should the Board wish to, clarification could be sought from MBIE as to what method was used for

NF-6.

The IA provides that, although unlikely, up to approximately 250 L of NF-6 could be used in a worst-

case scenario during the well plugging and abandonment activities, with a maximum volume of 57 L

used at any one well site. Based on this worst-case scenario, the IA has assessed the predicted

magnitude of environmental effects from the discharge of NF-6 to be negligible.

To ensure the risks are not underestimated, and to help consider any potential cumulative effects,

COPE notes the risks of the total amount of NF-6 (250 L) could be determined for the total amount of

wells that will be plugged.

I recommend that:

10 LC50 is the median lethal concentration, being a statistically derived concentration of a substance that can be expected to

cause death in 50 percent of organisms, units are in mg/L (water) or ppm.


28

a. clarification is sought from MBIE to confirm whether a CHARM or Non-CHARM method was

used to assess NF-6;

b. clarification is sought from MBIE as to how many of the cementing operations will have a BOP

and riser in place at the time; and

c. further information is requested from MBIE to address the observations made by COPE.

Biocide inhibited water discharges:

The production lines and gas-lift lines were previously chemically flushed and displaced with biocide

inhibited seawater as part of the demobilisation of the FPSO Umuroa. The biocide used in the

flowlines and gas-lift lines is a microbial growth retardant product known as BE-9. The IA provides that

BE-9 was dosed at a rate of 8L per 31,800L of seawater. Within the production flowlines and gas-lift

lines there is an estimated 176L of BE-9 with a combined volume of approximately 700,000L of

seawater (a BE-9 concentration of 251 parts per million (ppm)).

This biocide inhibited seawater will be discharged as part of the retrieval of the production flowlines

and gas-lift lines, as described in Sections 2.3.2 and 2.3.4 of the IA, as there is no practicable

alternative to the discharge.

The IA has assessed the predicted magnitude of environmental effects from the discharge of BE-9 to

be negligible. However, there are some limitations to the worst-case scenario used within this

assessment and uncertainties in regards to the persistence of BE-9 that make it unclear as to what the

likely environmental risk from the proposed discharge of the biocide inhibited seawater would be.

The active ingredient of BE-9 is tributyl tetradecyl phosphonium chloride (TTPC) and is classified as

being very ecotoxic to the aquatic environment and does not appear to be readily biodegradable. The

ERA within the IA classified both the known component and the BE-9 product as ‘chronic category 1’

(section 7.3.2.1.1). COPE’s review of the ERA provides a more precautionary approach to

categorising the product BE-9 based on the reliability of the information available. COPE has

categorised the product BE-9, as ‘acute and chronic aquatic toxicity category 1’.

The ERA within Section 7.3 of the IA describes the risks of BE-9 for the longest flowline using the non-

CHARM method. COPE notes Appendix J of the IA states that these products can be assessed using

CHARM however the ERA does not clarify the reasons why the product was assessed using the non-

CHARM method. Should the Board wish to, clarification could be sought from MBIE as to what method

was used for BE-9.

COPE notes concern that it is not clear why the risks were assessed for just the longest flowline rather

than the total of all the flowlines and gas-lift lines. Given the potential persistence of BE-9 in the

environment, to enable the Board to appropriately consider the worst-case scenario and the potential

cumulative effects of the proposed discharge of the biocide inhibited seawater, a worst-case scenario

that assesses the total discharge volume across all lines containing BE-9, is considered more

appropriate than the single longest flowline scenario presented within the IA.


29

Table 9 of the IA provides a summary of the BE-9 related information found within the SDS in

Appendix B. MBIE note that the active component within BE-9 (TTPC) constitutes 5-10% of BE-9,

meaning the concentration of this active component is at worst 25.1ppm. Based on the available data

from the BE-9 SDS (Appendix B of the IA) the lowest endpoint of the active component appears to

have an EC50 of 0.025 mg/L (acute value) for the crustacean Daphnia, is persistent (0% at 28 days)

and is not bioaccumulative.

Section 7.3.2.1.3 of the IA suggests the bulk of the active ingredient is likely to have become inactive

by the time it is discharged into the environment, as the rate of biodegradation of the active

component of BE-9 in water is thought to be 0% in 28 days and the minimum interval between dosing

of the production lines with BE-9 and the discharge of the biocide treated seawater is around 9

months.

As noted by both PDP and COPE, this biodegradation rate of 0% in 28days does not indicate that BE-

9 will be inactive after 9 months as section 7.3.2.1.3 of the IA appears to imply but indicates it is

persistent in the environment. Moreover, COPE note that the source of the data from this SDS is not

known and the validity of this biodegradation rate is not verifiable. Accordingly, there remains

uncertainty as to how active the BE-9 component of the Biocide Inhibited Water is likely to be after at

least 9 months, or how long any remaining active amount will take to degrade once discharged into

the environment. As a result, the likely environmental risk from the proposed discharge of the biocide

inhibited seawater is currently unclear.

I recommend the Board seek further information from MBIE to resolve the uncertainty regarding the

degradation rate of BE-9 and the poor clarity around the likely environmental risk of the proposed

discharge of the biocide inhibited seawater. In addition, to verify the validity and source of the

degradation rate cited in the BE-9 SDS, the Board could also choose to seek information directly from

the product manufacturer.

Potential cumulative effects:

The magnitude of impacts resulting from the discharge of biocide inhibited seawater and BOP

hydraulic fluids was assessed as being almost negligible within the IA. However, PDP notes there is

the potential for these almost negligible effects to accumulate with the effects of physical disturbance

of the seabed to produce a larger impact on benthic biological communities. PDP also notes that,

depending on the time of year that these impacts occur and the duration of impacts resulting from the

biocidal effects of the discharges, the recolonisation of seabed habitat following the decommissioning

programme may be delayed due to the availability of benthic larval supply for recruitment or the

mobility of surrounding biota to migrate into the affected seabed habitat.

As noted in paragraph 152-161 above, the Board may wish to seek further information, to provide

certainty regarding the degradation rate and longevity of BE-9’s active ingredient TTPC in seawater.

This information could also help the Board consider the potential of cumulative effects in combination

with information that could be sought from MBIE regarding the seasonality of the environmental effects

(see paragraphs 78-88 above).


30

Existing interests & Te Ao Māori

I consider a key issue will be the need for the Board to take into account the effects of the proposed

activity on existing interests in a manner that recognises and respects the Crown’s obligation to give

effect to the principles of the Treaty. The cultural impact assessment (CIA) presented in Appendix E of

the IA should be considered in this regard.

The Board will need to engage with the nature of the existing interests, recognising that the Taranaki

Iwi Taranaki Iwi Deed of Settlement is also underpinned by important cultural values such as

whanaungatanga and kaitiakitanga. With this in mind, the Board will need to consider how the impacts

on existing interests are approached and their relevance in terms of setting conditions.

The CIA (Appendix E of the IA) was prepared by Te Kāhui o Taranaki , Ngāti Kahumate, Ngāti Tara,

Ngāti Haupoto and Ngāti Tuhekerangi. The CIA covers existing interests of Taranaki Iwi, Ngāti

Kahumate, Ngāti Tara, Ngāti Haupoto and Ngāti Tuhekerangi, and provides an analysis of how their

existing interests could potentially be affected. The CIA is aligned to the EPA framework He Whetū

Mārama, providing analysis against the principles of Waka Hourua (Partnership), Whai Wāhi

(Participation), Pito Mata (Potential) and Tiakitanga (Protection). This analysis aligns to the need to

give effect to the Principles of the Treaty and underlying cultural values that may inform an analysis of

effects.

Under the principle of partnership, the CIA comments favourably on the partnership agreement

between MBIE and Te Kāhui o Taranaki, and the steps taken to produce the CIA. However, the CIA

also raises issues around how further implementation of a partnership relationship could occur and

also recommends conditions that provide assurance that whanaungatanga and kaitiakitanga will

continue to play a role in the management of effects through a kaitiaki forum.

Under the principle of participation, the CIA also notes that specific conditions are required to set

“structures” in place for existing interests of Taranaki Iwi, with further reference to a Kaitiaki forum and

co-development of any monitoring programme.

Under the principle of potential, the CIA notes opportunities to utilise and develop mātauranga, and

that recognition of the building of tikanga, kawa, whanaungatanga and kaitiakitanga as part of the

project is important. Under the principle of protection, the CIA notes that the IA was created in the

absence of an assessment against the current state of mouri.

To assist the Board in understanding and considering these matters further, I recommend the Board

seeks information from Ngā Kaihautū Tikanga Taiao (NKTT).

Environmental Monitoring

Section 2.6 discusses environmental monitoring in general terms and a proffered condition (in

Appendix A) proposes an Environmental Monitoring Plan (EMP) be prepared and submitted to the

EPA for approval prior to the exercise of any granted marine consent. The application also states that

the EMP will not be inconsistent with the statements made in the application.


31

Adequate environmental monitoring before and after the proposed activities take place is important to

establish whether the effects of the activities were in accordance with what was outlined within the

application and to determine compliance with any effects-based consent conditions. Accordingly, there

are several aspects the Board may wish to consider.

Consideration of Te Ao Māori:

Section 3.0 of the CIA provided in Appendix E of the IA, notes that adverse effects will remain until the

mouri of the area can rebalance itself. The cultural impact assessment within Appendix E also

highlights that co-development of an EMP is important to ensure “mātauranga has the opportunity to

inform the data relied upon for the performance of the Consent Holder”. Should the Board be minded

to grant the applications, the Board may wish to consider requesting the perspective directly from

iwi/hapū in regards to any potential monitoring related conditions.

The timing of monitoring activities:

The pre- and post-activity monitoring programmes are proposed to be undertaken for any well MBIE

intends to plug and abandon and any subsea infrastructure removal site. The application suggests that

monitoring of the effects of the proposed works will not be undertaken during the works themselves.

PDP observes that this means that monitoring is proposed solely to document the effects that have

occurred rather than to detect adverse effects and inform the activities being undertaken in time to

reduce or avoid further adverse effects. PDP also observes that the likely time delays between works

being completed and monitoring occurring mean that the potential for detecting and documenting the

full extent of the impacts of the activity will be limited.

The discharge of harmful substances:

PDP also note that the general monitoring discussed in the application suggests that there will be no

monitoring associated with the proposed discharge of harmful substances. PDP suggests that the

marine discharge consent could include a monitoring programme that includes elements capable of

detecting significant adverse effects resulting from the discharge activities.

While it appears that seabed monitoring is practicable, PDP note that water quality monitoring may

also be feasible to validate the environmental assessment within the application. Such monitoring

could be undertaken soon after the removal of the subsea infrastructure to confirm, or otherwise, that

the discharge plume behaves as estimated within the IA. Should the Board wish to, further information

could be sought from MBIE on why water quality monitoring to validate the nature, magnitude and

extent of the discharge activities is not being proposed.

PDP also note there are no proposed monitoring actions that would establish the presence of any

unintended or accidental discharges, how that monitoring will be reported, or enable any contingency

actions. Should the Board be minded to grant the applications, the Board may wish to consider this

aspect when considering any draft conditions in regards to environmental monitoring requirements.


32

The purpose of an EMP & setting conditions:

MBIE has proffered conditions that will require the development of an Environmental Monitoring Plan.

In general, the EMP should set out the hypotheses and methods MBIE will follow when undertaking

any environmental monitoring before and after the decommissioning activities. Pre-decommissioning

monitoring should be comparable to post decommissioning monitoring in terms of season, extent,

parameters measured for example.

Sections 63(2)(a)(iii) and (v) allows the Board to impose conditions that require a consent holder to

undertake monitoring, and to provide information to the EPA for audit. Section 66 provides additional

guidance on monitoring conditions.

Should the Board be minded to grant the applications, the Board will need to turn its mind to what

standards and information the EMP should meet and prescribe these within the consent conditions.

Conclusions and Recommendations

Having considered MBIE’s application documents and the information provided by external experts

and government agencies, I consider that there are seven key issues relating to the applications and

the proposed activities:

a. Ecological receptors & seasonal sensitivity

b. Biosecurity risk management

c. Seabed disturbance

d. Well plugging & abandonment

e. Discharge uncertainties

f. Existing interests & Te Ao Māori

g. Environmental Monitoring

If the Board was of a mind to seek further information on any of the matters set out in this report, it

may:

a. request information under sections 54 and 56 of the EEZ Act being mindful on restrictions as to

timing issues for when such information can be requested.

b. direct expert conferencing on relevant topics including inviting experts to consider and respond

to questions specified by the Board; or

c. convene a hearing and direct questions to relevant expert witnesses at that hearing.

Based on my discussion of key issues, the Board may wish to seek further information/clarification

from the applicant under section 54 of the EEZ Act on the following aspects:


33

a. variation in receptor sensitivity as a result of seasonal factors and help ensure that timing of the

proposed works would avoid or minimise adverse environmental effects and enable healthy

benthic recovery;

b. the likely rates of recolonisation and benthic biological community rehabilitation and the

processes involved;

c. the integrity risks of the Pateke-3H umbilical/Pateke-4H flowline crossing structure during

retrieval;

d. how MBIE intends to plug and abandon Tui SW-2MBIE to ensure two competent barriers are in

place in accordance with Oil and Gas UK (OGUK) Well Decommissioning Guidelines – Issue 6,

June 2018;

e. why no shallow environmental cement plugs are proposed for the planned plugging and

abandonment work;

f. clarify and address the findings within the COPE review of the IA’s environmental risk

assessment for the discharge of harmful substances;

g. clarification as to whether the hydraulic flying leads from the distribution units to the end users

been flushed and left with Transaqua Ht2 and what is their potential for discharging harmful

substances when cut;

h. clarification as to whether all of the cementing operations will have a BOP and riser in place at

the time of plugging; and

i. why water quality monitoring to validate the nature, magnitude and extent of the discharge

activities is not being proposed.

The Board could also commission further information/clarification from any person (such as external

consultants or government agencies) under section 56(1)(f) the EEZ Act regarding the following:

a. information from the manufacturer of BE-9 that provides the source and validation of the data

behind the biodegradation rate presented in the SDS for BE-9; and

b. information from NKTT in regards to the IA’s consideration of existing interests & Te Ao Māori.

END


34

Appendix 1: Documents reviewed for the key issues report Documents reviewed for the key issues report.

Date Document Name Author/ Organisation

Document description

Application documents

21 July 2021

Tui Field Decommissioning

Marine Consent and Marine

Discharge Consent Application

MBIE & SLR Application and IA (including10

supporting appendices)

Further information received by the EPA

11 September 2021

Tui Oil Field Decommissioning

Application Review -

Review of SURF and Wells P&A application

Intecsea EPA external expert peer review of the application and IA in terms of best industry practice

8 September 2021

Tui Oil Field Decommissioning –

Review of Application

Documents

Pattle Delamore Partners (PDP)

EPA external expert peer review of the application and IA in terms of marine ecology

9 September 2021

EEZ100020- advice regarding

the ecotoxicity and fate

properties of five substances

COPE

Environmental

Consultancy

EPA external expert peer review of the

application and IA in terms of

ecotoxicology & CHARM, Non-CHARM

assessment

03 September 2021

Letter response – Request for

advice under section 56 of the

Exclusive Economic Zone and

Continental Shelf

(Environmental Effects) Act

2012 regarding the MBIE

Applications – EEZ100020-1

and EEZ100020-2

Department of

Conservation

Response to EPA questions on marine

mammals and rare/vulnerable

ecosystems

27 August 2021




Continental Shelf




and EEZ100020-2

WorkSafe Answers to EPA questions on health and

safety

06 September 2021




Continental Shelf




and EEZ100020-2

MPI Answers to EPA questions on fisheries

07 September 2021 Letter response – Request for

advice under section 56 of the MaritimeNZ

Answers to EPA questions on maritime

regulatory obligations


35


Continental Shelf




and EEZ100020-2

14 September 2021

Email response – Request for



Continental Shelf




and EEZ100020-2

Biosecurity

New Zealand

Answers to EPA questions on Biosecurity

regulatory obligations


36