Harriet Charlie Plug and Abandonment BRIDGING DOCUMENT SUMMARY

709 Pages·2016·5.56 MB·English

by  Lucy Muir

Harriet Charlie Plug and Abandonment

EA-60-RI-10090.03

BRIDGING DOCUMENT SUMMARY

REV DATE DESCRIPTION BY CHK EM/PM

1 01/02/16 Issued to DMP LM HC -
A 01/02/16 Internal Review LM HC -

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
EA-60-RI-10090.03
CONTENTS
1. INTRODUCTION ............................................................................................................................... 4
1.1 Compliance ................................................................................................................................... 4
2. LOCATION OF THE ACTIVITY ............................................................................................................. 4
3. DESCRIPTION OF THE RECEIVING ENVIRONMENT ............................................................................. 6
3.1 Physical and biological environment .............................................................................................. 6
3.2 Environmental Management .......................................................................................................... 6
3.2.1 Socio-economic environment ............................................................................................................... 6
4. ACTIVITY DESCRIPTION .................................................................................................................... 6
5. CHEMICAL DISCLOSURE AND HYDROCARBON MANAGEMENT .......................................................... 8
5.1 Chemicals ...................................................................................................................................... 8
5.2 Hydrocarbons ................................................................................................................................ 8
6. ENVIRONMENTAL HAZARDS AND CONTROLS ................................................................................... 8
7. MANAGEMENT APPROACH .............................................................................................................. 9
8. CONSULTATION ............................................................................................................................. 10
9. CONTACT DETAILS ......................................................................................................................... 10
10. REFERENCES ................................................................................................................................ 10

TABLES
Table 2-1: Location of the Harriet Charlie Platform .......................................................................................... 4
Table 7-1: Additional/Amended Environmental Hazards and controls....................................................... 9

FIGURES
Figure 2-1: Location of Harriet Charlie platform and surrounding sensitive habitats ...................................... 5

APPENDICES
Appendix A – Chemical Disclosure .................................................................................................................. 11
Appendix B - MSDS .......................................................................................................................................... 12
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ABBREVIATIONS

ABN Australian Business Number
ALARP As low as reasonably practicable
AMSA Australian Maritime Safety Association
BD Bridging Document
BOP Blow-out preventer
DMP Department of Mines and Petroleum
EP Environment Plan
GWSWA Generic Well Suspension and Well Abandonment [EP]
MARPOL International Convention for the Prevention of Pollution from Ships
NTP Noble Tom Prosser
NWS North West Shelf
OSCP Oil Spill Contingency Plan
P&A Plug and Abandonment
Ppm Parts per million
ROB Remotely Operated Vehicle
STP Sewage Treatment Plant
VI Varanus Island
WA Western Australia
WMP Well Management Plan
WAC Well Acceptance Criteria
WLMS Well Lifecycle Management System
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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), with the same ABN of 39
009 310 964. Other entities in the former Apache Energy group have also been renamed, retaining the
ABN/ ACN, for example Apache Northwest was renamed Quadrant Northwest Pty Ltd. 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 (OSCP). 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 4 well locations at the
Harriet Charlie monopod using a jack-up drilling rig, likely to be the Noble Tom Prosser (NTP) under the
Generic Well Suspension and Well Abandonment EP (EA-00-RI-10027). The purpose of the P&A campaign is
to establish permanent barriers to prevent migration of hydrocarbons to the surface.
The Harriet Charlie monopod is located within the Varanus Island (VI) hub in Production Licence area TL/1
at 24.5 m water depth. The Hub is operated by Quadrant Energy, on behalf of the Joint Venture partners.
The planned activities will be taking place within the 500 m exclusion zone of the Harriet Charlie monopod.
Mobilisation of the NTP to the Harriet Charlie monopod is expected to commence January/February 2015
and P&A activities will take approximately 43 days to complete, dependent on weather, scheduling and
well conditions. Operations shall be conducted 24 hours a day.
1.1 Compliance
The Harriet Charlie Plug and Abandonment Bridging Document (BD) was prepared for the proposed
activities and the DMP determined on the 22nd January 2016 (EARS –EPBD-57979) that revision 2 of the BD
meets 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.
This summary has been prepared in accordance with Regulation 11(7) of the (P(SL)(E) Regulations and
section 2.4 of the DMP Guidelines for the Preparation and Submission of an EP.
The proposed plug and abanondment campaign will be managed in accordance with the accepted Generic
Well Suspension and Well Abandonment Environment Plan (GWSWA EP) (EA-00-RI-10027) and the Harriet
Charlie Plug and Abandonment Bridging Document (Document Number EA-60-RI-10090) as they cover the
expected environmental risks and control measures to be undertaken.
2. LOCATION OF THE ACTIVITY
The surface location of the Harriet Charlie platform is shown in Figure 2-1 and the location coordinates
(GDA94 Zone 50) are provided in Table 2-1 below.
Table 2-1: Location of the Harriet Charlie Platform
Platform Longitude Latitude
Harriet Charlie 115° 37' 37.764” E 20° 35' 20.403” S

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Figure 2-1: Location of Harriet Charlie platform and surrounding sensitive habitats
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3. DESCRIPTION OF THE RECEIVING ENVIRONMENT
3.1 Physical and biological environment
The Harriet Charlie monopod is located in the North-West Marine Region, within the Northwest Shelf
Province (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. Surface sediments in the area are
predominantly composed of skeletal remains of marine fauna, with lenses of weathered sands. Regionally,
the seafloor tends to be flat unconsolidated and sedimentary with occasional calcarenite rock outcrops.
The seabed immediately around the Harriet Charlie monopod is similarly flat and featureless with medium
to coarse sand with some gravel.
The proposed activities will occur in January-February, dependent upon a suitable weather window and
availability of equipment and personnel. This timing overlaps with a number of key ecological events
including Coral spawning, dugong breeding and turtle nesting.
3.2 Environmental Management
The proposed activities is expected to commence in February, dependent upon a suitable weather window
and availability of equipment and personnel. This timing overlaps with a number of key ecological events
including coral spawning, dugong breeding and turtle nesting 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 short term nature of discharges.
3.2.1 Socio-economic environment
The standard 500 m exclusion zone to non-Quadrant Energy vessels will be maintained around the Harriet
Charlie monopod and NTP during the activities. Therefore the proposed activities are not expected to
interfere with other users of the sea. Quadrant Energy has committed to notifying stakeholders four weeks
prior to activity commencement, as per the GWSWA EP. No non-government stakeholders of relevance to
the Harriet Charlie P&A activities have been identified as the operations take place from the existing
monopod location, around which exclusion zones are already in place. No potentially significant impacts to
stakeholders have been identified from the proposed activities
4. ACTIVITY DESCRIPTION
Mobilisation
The Noble Tom Prosser (NTP) jack-up drilling 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 Harriet Charlie monopod. Access stairs will be installed on the conductor
tension deck that will lead down to the monopod main deck to complete works as required.
Re-entry and well kill
The wells are currently shut in and have hydrocarbons trapped in both the tubing and production annulus
that was used for gas lift.
Wireline pressure control equipment will be rigged up on the well. The tubing will be bullhead killed with
kill weight brine. A 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. The reservoir crude will be flared or
pumped into a tote tank and brought onshore for disposal. The brine and packer fluid will be filtered and
discharged overboard if the oil in water concentration is < 30 ppm prior to discharging overboard.
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Disposal Well
There is an opportunity to use the HC-4 well as a disposal well for well fluids returned from Harriet C1, C2
and C3, however this is a contingency only. In the event of any technical difficulties, the well fluids will
otherwise be filtered through a flowback package and oily water filtration system prior to being discharged
overboard. The flowback package is a simplified well test spread. It primarily consists of a choke manifold to
control the flow and pressure and a surge tank and a gauge tank.
Pull Completion
The Xmas tree will be removed and the riser and BOPs rigged up and tested. The completion will be pulled
allowing access to the production casing.
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 the Harriet Charlie well
abandonments. Surface cement plugs are set to provide the required permanent subsurface barriers.
Inhibited kill weight fluid is left between the cement plugs. After setting a cement plug, the workstring,
cement unit and surface lines are all flushed with brine or milling fluid and the contaminated returns
discharged overboard.
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.
Once the subsurface barriers are in place, the BOP and riser will be removed. The surface casings will be cut
above the seabed and recovered. The remainder of the surface casings will be removed to seabed during
final platform decommissioning (subject to an additional EP).
Demobilisation
The platform is cleared of loose materials and a remote operated vehicle (ROV) seabed clearance survey
may be carried out in line with Section 3.6 of the GWSWA EP. The cantilever is skidded in and the rig jacked
down. Vessels will pull the rig clear of the monopod and the rig will be towed out of the 500 m exclusion
zone.

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5. CHEMICAL DISCLOSURE AND HYDROCARBON MANAGEMENT
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 (approximately 20 years) and data on all the
chemical components is limited. DMP have advised that these chemicals are not subject to chemical
disclosure if they are pumped into the disposal well. 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
 Hazard Reporting Incident Notification and Investigation Procedure (AE-91-IF-002).
6. ENVIRONMENTAL HAZARDS AND CONTROLS
An environmental risk assessment workshop was held on 22/10/2015 with key personnel from the
Quadrant Energy Drilling, Operations and HSE team. Additional environmental risks to those identified in
the GWSWA EP relate to:
 Potential oily water from reservoir crude from well intervention / wireline operation activities and
discharged overboard;
 Loss of well control1 during abandonment works as a result of the rig intervention campaign: 3,150 m3
of crude oil and 0.036 Bscf of gas for 77 days (required duration to drill a relief well and kill the well);
 Discharge of annulus and packer fluid; and
 Discharge of treated sewage from the sewage treatment plant in port limits.

1 Additional oil spill modelling was completed for the loss of well control to ascertain the magnitude and extent of the release,
change in consequence or increase in environmental risk, and if any additional spill response is needed; the modelling and
assessment concluded that the VI OSCP (EA-60-RI-186.2) is fit for purpose for this additional spill scenario
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However these were all deemed as having a ‘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.
As the activities occur over 6 km from the nearest turtle nesting beaches there are no additional controls
required for management of platform lighting.
7. MANAGEMENT APPROACH
The activities will be managed in compliance with the GWSWA EP (Document Number EA-00-RI-10027), and
the Harriet Charlie Plug and Abandonment Bridging Document (Document number EA-60-RI-10090).
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. Upon review of
the EP Commitments in the GWSWA EP, a number of performance standards have been found to be
inconsistent with current regulations and/or practises within Quadrant Energy, these are included in Table
7-1.
Table 7-1: Additional/Amended Environmental Hazards and controls
Hazard/Activity Controls
Potential oily water from reservoir  Oily water generated on the rig during P&A activities will be discharged
crude from well intervention / through oil-water filtration equipment, which will be:
wireline operation activities and o Designed to reduce oil-in-water to < 30 parts per million (ppm)
discharged overboard o Calibrated prior to use
 An oil-in-water monitor shall be used to assess the performance of the
filtration equipment
Loss of well control during  Quadrant Well Management Plan (WMP) includes control measures for
abandonment works as a result of the well integrity that reduce the risk of an unplanned release of
rig intervention campaign hydrocarbons
 Rig Safety Case includes control measures for well control that reduce the
risk of an unplanned release of hydrocarbons
 Quadrant Well Acceptance Criteria (WAC) for critical well operations and
integrity aspects are achieved. WAC will be selected based on the well
objectives and Quadrant’s Well Lifecycle Management System (WLMS)
technical standards
 Implement Relief Well Plan for Source Control:
o Quadrant Energy will acquire and mobilise an appropriate drill
unit to site within 33 days to drill the relief well.
o Plans for drilling a relief well will be completed within 31 days
and will begin at the same time as well intervention options (to
stop the flow of hydrocarbon or to permanently secure the
primary well) are being considered and/or implemented.
o Well kill modelling will be conducted to confirm the fluid rates,
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pump rates and volumes that will be required to maintain
integrity of the primary bore.
Discharge of annulus and packer fluid  Annulus and packer fluids in the wells are risk assessed in accordance
with Quadrant’s Drilling 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, and are
unable to be discharged downhole, the fluids will be contained and
transported to shore for disposal at a government approved disposal
facility.
Discharge of treated sewage from For the duration of the activity, sewage will only be discharged from the rig or
support vessels if it has been treated in an AMSA or MARPOL Annex IV
the sewage treatment plant in port
approved Sewage Treatment Plant (STP) is maintained through the planned
limits maintenance system AND:
 The treated effluent does not cause discoloration or floating solids; and
 The rig/vessel is not within a Marine Nature Reserve or sanctuary zone
within Marine Parks.
 If the rig or vessel does not have approved STP, no sewage to be
discharged in State waters

Some performance standards outlined in the GWSWA EP are not applicable to the activity such as, some
elements are not being conducted (e.g. diving operations, 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.

8. CONSULTATION
Quadrant Energy has committed to notifying stakeholders four weeks prior to activity commencement, as
per the GWSWA EP. No non-government stakeholders of relevance to the Harriet Charlie P&A activities
have been identified as the operations take place from the existing monopod location, around which
exclusion zones are already in place. No potentially significant impacts to stakeholders have been identified
from the proposed activities.
9. CONTACT DETAILS
Further information about the plug and abandonment activities can be obtained from Ashlee Crabbe on
[phone] 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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