Chervil Plug and Abandonment BRIDGING DOCUMENT SUMMARY

586 Pages·2016·7.91 MB·English

by  Doyle, Anthony

Chervil Plug and Abandonment

AI-65-RG-10009.02

BRIDGING DOCUMENT SUMMARY

REV DATE DESCRIPTION BY CHK
A 23/05/2016 Internal Review S2V LM
0 08/06/16 Submission to DMP S2V LM
1 13/06/16 Re-submission with full MSDS Appendix S2V LM
2 16/06/16 Re-submission with new chemical HC LM
3 21/06/16 Re-submission of MSDS Appendix HC LM

Holders of Controlled Copies:

Perth Library

Any hard copy of this document, other than those identified above, are uncontrolled. Please refer to the
Quadrant Energy intranet site for the latest revision.
AI-65-RG-10009.02
CONTENTS
1. INTRODUCTION ............................................................................................................................... 3
1.1 Compliance ................................................................................................................................... 3
2. LOCATION ....................................................................................................................................... 3
3. DESCRIPTION OF THE RECEIVING ENVIRONMENT ............................................................................. 5
3.1 Physical and biological environment .............................................................................................. 5
3.2 Environmental Management .......................................................................................................... 5
3.2.1 Socio-economic environment ............................................................................................................... 5
4. ACTIVITY DESCRIPTION .................................................................................................................... 5
5. CHEMICAL DISCLOSURE ................................................................................................................... 6
5.1 Chemicals ...................................................................................................................................... 6
5.2 Hydrocarbons ................................................................................................................................ 6
6. ENVIRONMENTAL HAZARDS AND CONTROLS ................................................................................... 7
6.1 Risk assessment ............................................................................................................................. 7
7. MANAGEMENT APPROACH .............................................................................................................. 7
8. CONSULTATION ............................................................................................................................... 8
9. CONTACT DETAILS ........................................................................................................................... 8
10. REFERENCES .................................................................................................................................. 8

TABLES
Table 2-1: Location of the Chervil subsea manifold .................................................................................. 3
Table 7-1: Additional Environmental Control Measures ........................................................................... 7

FIGURES
Figure 2-1: Location of Chervil subsea manifold ...................................................................................... 4

APPENDIX
Appendix A: Chemical Disclosure
Appendix B: MSDS

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1. INTRODUCTION
On 5 June 2015, a consortium comprising Brookfield Asset Management and Macquarie Capital acquired
Apache Energy’s Western Australian oil and gas assets by purchasing Apache Energy’s corporate group. With
effect from 23 June 2015, the name of the entity formerly known as Apache Energy Limited ABN 39 009 310
964 changed to Quadrant Energy Australia Limited (Quadrant Energy). Other entities in the former Apache
Energy group have also been renamed, retaining the ABN. Quadrant Energy Australia Ltd and its affiliates will
assume responsibility for all commitments and obligations pursuant to all Environment Plans, and Oil Spill
Contingency Plans (OSCPs). Quadrant Energy Australia as the Operator remains the same company, with the
same HSE systems, policies and procedures in place, and therefore the manner in which the environmental
impacts and risks of an activity are managed do not change.
Quadrant Energy proposes to carry out plug and abandonment (P&A) activities at two well locations at the
Chervil monopod using a jack-up drilling rig, under the Department of Mines and Petroleum (DMP) approved
Generic Well Suspension and Well Abandonment EP (GWSWA EP; EA-00-RI-10027). The purpose of the P&A
campaign is to establish permanent well barriers.
The Chervil monopod is located in TP/7, in a water depth of 17 m. The two wells, Chervil-5 and Chervil-6,
were drilled in July 1989 and July 1997 respectively. The pipelines between the monopod and Airlie Island
have been disconnected and flushed with treated seawater. The planned activities will be taking place within
the 500m exclusion zone of the Chervil monopod as marked on Airlie navigational charts.

1.1 Compliance
The Chervil Plug and Abandonment Bridging Document (BD) was prepared to meet the requirements of
Regulation 11(1) of the Petroleum (Submerged Lands) (Environment) Regulations 2012 (P(SL)(E) Regulations).
The well plug and abandonment activities will be conducted in accordance with all applicable legislation and
regulations and specifically to meet the requirements of the Petroleum (Submerged Lands) Act 1982 (WA)
and its regulations.
The proposed plug and abandonment campaign will be managed in accordance with the accepted Generic
Well Suspension and Well Abandonment Environment Plan (GWSWA EP) (EA-00-RI-10027), the Varanus
Island Hub Operations Oil Spill Contingency Plan (EA-60-RI-186.2) and the Chervil Bridging Document (AI-65-
RG-10009) as they cover the expected environmental risks and control measures to be undertaken.
2. LOCATION
The surface location of the Chervil monopod is shown in Figure 2-1, with co-ordinates provided in Table 2-1.
Table 2-1: Location of the Chervil subsea manifold
Latitude / Longitude Northings / Eastings
Chervil monopod Latitude: 21° 18’ 31.045” South Easting: 316235.54mN
Longitude: 115° 13’ 42.114” East Northing: 7642662.8mE
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Figure 2-1: Location of Chervil monopod
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3. DESCRIPTION OF THE RECEIVING ENVIRONMENT
3.1 Physical and biological environment
The Chervil monopod is located in the North-West Marine Region (DEWHA, 2008) which lies primarily on the
continental shelf between North West Cape and Cape Bougainville. The area has a dynamic oceanographic
environment, influenced by strong tides, cyclonic storms, long-period swells and internal tides. Regional
surveys on the NWS indicate the seafloor composition is uniform throughout the area, but with spatial
variation in the grain size and origin of the surface sediments. Regionally, the seafloor tends to be flat,
unconsolidated and sedimentary with occasional calcarenite rock outcrops. The seabed surrounding the
Chervil monopod is similarly flat and featureless with medium to coarse sand with some gravel.
3.2 Environmental Management
The proposed activities will commence in late Q2 or Q3 2016, dependent upon a suitable weather window
and availability of equipment and personnel. This timing overlaps with a number of key ecological events
including turtle nesting and whale migration (as described in the GWSWA EP (EA-00-RI-10027). It is not
expected that the marine environment or their sensitive features will be impacted from these activities given
the distance from shorelines and migration corridors, and the short term nature of discharges.
3.2.1 Socio-economic environment
The standard 500m exclusion zone to non-Quadrant Energy vessels will be maintained around the Chervil
monopod and jack-up rig during the activities. Therefore the proposed activities are not expected to interfere
with other users of the sea.

4. ACTIVITY DESCRIPTION
Move on and rig up
The rig will be moved into position using up to three vessels prior to jacking out of the water and carrying out
the preload. The rig is jacked up to its operating height and the cantilever skidded out over the Chervil
monopod.
Re-entry and well kill
The annulus riser will be run and hooked up to the well. The flowback package will be rigged up and tested.
The tubing will be bullhead killed and the annulus killed by bleeding and lubricating in kill fluid (heavy fluid
that provides an overbalance to well pressure). The wireline riser and pressure control equipment will then
be rigged up. A wireline plug will be set in the packer and the tubing cut just above the packer. The annulus
will be circulated to kill weight brine to remove any hydrocarbons. Returns which will include the packer fluid
will be either circulated through the rig gas separation system or the flowback package. The gas will be either
vented or flared depending upon the volume and pressure.
During bleed-off operations (de-pressurisation of trapped gas), the preference and base plan will be to flare
any gas or oil returns. In the event that the gas is unable to be flared due to insufficient volume and pressure
to sustain a flame, gas will be cold vented to the atmosphere.
The reservoir crude oil will be flared or pumped into a tote tank and brought onshore for disposal. Oily water
and packer fluid will be filtered and discharged overboard if the oil in water concentration is < 30 ppm prior
to discharging overboard.
Pull Well Completion
The drilling riser and BOPs will be rigged up on the well. The well completion will be pulled allowing access
to the production casing. Loss circulation material (LCM) may be pumped and typically remains downhole if
the well experiences losses to the formation. If there is a casing leak then either lost circulation material
(LCM) or cement may be pumped to stop the downhole leak.
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Abandon well subsurface
Cement plugs, including bridge plugs, will be set to prevent slumping in the well. Alternatively hi-vis pill(s)
will be pumped instead of the bridge plug. If there is poor annular hydraulic isolation, remediation will be
done by section milling a window in the casing and setting a formation cement plug across the entire
wellbore. Section milling is a remedial cementing method and is a contingency for these well abandonments.
During this process, metal swarf is generated. A dedicated swarf recovery system segregates the swarf which
is recovered, stored in covered skips then shipped to shore for disposal. Any non-magnetic solids pass
through and flow down to the rig’s solids control equipment (shale shakers). The cuttings are removed and
discharged overboard at surface and the milling fluid returned to the mud pits. A cement plug is placed
across the window to provide a permanent barrier.
Explosive-based tools may be deployed in the well to carry out various operations such as tubing cutting or
punching circulation holes in the casing. Once detonated, the tools are retrieved to surface. The explosives
utilised for these types of operation are Cartridges and Pellets, Division 1.4 and Electric Detonators. These
explosives are not subject to chemical disclosure.
Move off
An ROV seabed clearance survey may be carried out in line with Section 3.6 of the GWSWA EP. The cantilever
will be skidded in and the rig jacked down. Vessels will pull the rig clear of the abandoned wells and the rig
towed out of the 500 m exclusion zone.
5. CHEMICAL DISCLOSURE
5.1 Chemicals
Full chemical disclosure is provided in Appendix A with details of the Material Safety Data Sheets in Appendix
B. This includes the use of drilling and well testing chemicals, cementing chemicals and contingency chemicals
used downhole. The volumes disclosed are based on the planned well activities and some contingency
volumes in the event of any problems on the wells.
It is noted that the packer fluid and annulus fluids currently in the wells have been downhole for a number
of years and were injected prior to the Petroleum (Submerged Lands) (Environment) Regulations 2012
coming into effect. These chemicals have degraded over time and data on all the chemical components is
limited. DMP have advised that these chemicals are not subject to chemical disclosure. If the chemicals are
to be pumped overboard, the available information will be reviewed taking into consideration the
degradation over time, available ecotoxicity data (including bioaccumulation and biodegradation),
concentrations and volumes, to ensure that discharge to sea is acceptable to Quadrant Energy.
Drilling, well testing, cementing and contingency chemicals selected for the activity which will not be
discharged down hole but may be discharged overboard during the operations are not subject to chemical
disclosure; however as described in the GWSWA EP, Quadrant Energy will select chemicals in accordance
with the Drilling Fluid and Chemical Risk Assessment Procedure (EA-91-II-008)
5.2 Hydrocarbons
If hydrocarbons are spilt on-board they will be cleaned up immediately and the soiled clean-up materials
collected in plastic bags for disposal to the mainland.
In the unlikely event that a significant hydrocarbon spill occurs during activities, Quadrant Energy’s
emergency response procedures are in place to cover such an occurrence. These include:
 Varanus Island Hub Operations Oil Spill Contingency Plan (OSCP; EA-60-RI-186.2);
 Varanus Island Hub Incident Response Plan (AE-00-ZF-044);
 Incident Command and Management Manual (AE-00-ZF-025);
 NWS Operations Consolidated Cyclone Response Plan (AE-91-IF-010); and
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 Hazard Reporting Incident Notification and Investigation Procedure (AE-91-IF-002).
6. ENVIRONMENTAL HAZARDS AND CONTROLS
6.1 Risk assessment
An environmental risk assessment workshop was held on 22/10/2015 with key personnel from the Quadrant
Energy Drilling, Operations and HSE departments. Additional environmental risks to those identified in the
GWSWA EP relate to:
 Potential Oily water Discharge from well intervention/wireline operations
 Release of crude oil from Chervil subsea manifold from loss of well control1
 Discharge of annulus and packer fluid
However these were all deemed as having an ‘As Low As Reasonably Practicable’ (ALARP) level inherent risk.
With control measures in place (see Table 7-1), these risks have an inherent risk ranking of ALARP or
Tolerable.

7. MANAGEMENT APPROACH
The proposed activities will be carried out under the GWSWA EP (EA-00-RI-10027), and the Chervil Plug and
Abandonment Bridging Document (AI-65-RG-10009).
The primary goal of the environmental guidelines and commitments outlined in the EP and the BD are to
direct, review and manage activities so that environmental impacts and risks are continually being reduced
to ALARP. The identified potential hazards and environmental management controls for this activity that are
additional to those identified in the accepted GWSWA EP are summarised in Table 7-1.
Some performance standards outlined in the GWSWA EP are not applicable to the activity due to some
elements not being conducted (e.g. flushing activities), the distance of the activity from shorelines (e.g.
lighting management), or there are performance standards which are not relevant to rig-specific activities.
These performance standards have therefore been removed from the commitments register that will be
adhered to for this activity and will not be reported against in the end of activity report.
Table 7-1: Additional Environmental Control Measures
Hazard Controls
Oily water generated on the rig during P&A activities will be discharged through oily water
Planned discharges to the
filtration equipment, which will be:
marine environment
 Designed to reduce oil-in-water to < 30 parts per million (ppm)
 Monitor calibrated prior to use
 An oil-in-water monitor shall be used to assess the performance of the filtration
equipment
Release of crude oil from Chervil Quadrant Well Management Plan (WMP) includes control measures for well integrity that
monopod from loss of well reduce the risk of an unplanned release of hydrocarbons. [Quadrant drilling standard ref: DC-
control CM-017-EPS-001]
Release of crude oil from Chervil Rig Safety Case includes control measures for well control that reduce the risk of an
monopod from loss of well unplanned release of hydrocarbons. [Quadrant drilling standard ref DC-CM-017-EPS-002]
control

1 New spill modelling has been conducted to determine the magnitude and extent of the potential release. The modelling outcome
indicates that the potential impacts from this loss of well control scenario are within the spatial extent of the spills and sensitive
receptors already described within the GWSWA EP; a worst case scenario has been adopted (although highly unlikely) based on the
well flowing at pressures when first drilled.
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Hazard Controls
Release of crude oil from Chervil Quadrant Well Acceptance Criteria (WAC) for critical well operations and integrity aspects
monopod from loss of well are achieved. WAC will be selected based on the well objectives and Quadrant’s Well
control Lifecycle Management System (WLMS) technical standards.
Discharge of annulus and packer Annulus and packer fluids in the wells are risk assessed in accordance with Quadrant’s Drilling
fluid Fluid and Chemical Risk Assessment Procedure prior to discharge to the marine environment.
In the event that the annulus and packer fluids are not deemed acceptable for discharge in
accordance with the procedure, the fluids will be contained and transported to shore for
disposal at a government approved disposal facility.

8. CONSULTATION
Quadrant considers that consultation with key stakeholders for this activity has been adequate; all
stakeholders and relevant parties have been actively engaged by Quadrant regarding its activities on the NW
Shelf (including this activity) by means of a Quarterly Consultation Updates circulated in September 2015 and
March 2016. No objections or concerns have been raised by stakeholders via this method of consultation.
9. CONTACT DETAILS
Further information about the plug and abandonment activities can be obtained from Ashlee Crabbe on (08)
6218 4972 or email [email protected].

10. REFERENCES
DEWHA (2008). The North-west Marine Bioregional Plan: Bioregional profile, a description of the
ecosystems, conservation values and uses of the north-west marine region. Department of the
Environment Water, Heritage and the Arts, Canberra, Australia.

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Appendix A: Chemical Disclosure

Chervil Plug and Abandonment
A. SYSTEM DETAILS (System as per Generic EP)
OPERATOR: Quadrant Energy
PROJECT / WELL: Chervil P & A’s
SYSTEM: Well Abandonment - Hi-Vis Pill
TOTAL VOLUME OF SYSTEM: 500 m3

B. PRODUCT LIST
Fluid name Product Supplier Purpose Product in Toxicity & Ecotoxicity Info MSDS
(and Volume) Name system Attached
(concentration
%)
Water Locally sourced Base Fluid 99% N/A – Natural product – exempt from chemical disclosure N/A
FLOWZAN® M-I SWACO Viscosifier 0.76% Acute Mammalian Toxicity Y
Biopolymer
LC50: no data available. A similar product by a different supplier lists LD50
rat (oral): >5,000 mg/kg.
Chronic Toxicity
Not carcinogenic (Cat 1 & 2), mutagenic (Cat 1 & 2) or toxic for reproduction
(Cat 1, 2 & 3).)
Aquatic Toxicity
Component 1 (95-99%)
Skeletonema costatum EC50 (72h): 207 mg/L
Hi-Vis pill
Acartia tonsa LC50 (48h): 259 mg/L
(500 m3)
Scophthalmus maximus LC50 (96h): >1,000 mg/L

Component 2 (1-5%)
OSPAR PLONOR Listed
OCNS Listed: E
Natural product – exempt from chemical disclosure
Biodegradation
Ready Biodegradation Test
OECD 306: 49%
Bioaccumulation