Efficiency, Integration and Collaboration

- Delivering SNS Decommissioning

Richard Tocher

Decommissioning Manager1

2

SNS Infrastructure

Fast Facts

• 38 platforms

• 9 subsea installations

• 140,000 tonnes

• 145 wells

• 1,650 km of pipelines

• Onshore terminal

• 3rd party infrastructure

• Multiple joint ventures

Cessation of Production

• Viking – January 2016

• LOGGS – August 2018

• CMS – August 2018

Decommissioning commenced June 2014

3

Campaign Strategy: Minimise Risk and Cost

ACCOM. WORK VESSEL (AWV)

1. Final clean2. Stabilisation3. Pre-rig abandonment

1: FINAL CLEAN

• Topside purging• Flowline destruct• Pipeline cleaning

2: STABILISATION

• Dropped object protection• Asset integrity repairs• Handrail/grating repairs

2: REMOVAL PREPARATION

• Installation of lifting aids• Reinstating access

3: PRE-RIG ABANDONMENT

• Detailed survey• Clear access paths• P&A pre-works

1: P&A

• Set barriers• Pull conductors

3: FINAL DISCONNECT

• Commission solar powered AtoN

• Transition to cold stack

SIMOPS SIMOPS

RIG (ENSCO 92)

1. Well P&A2. Removal preparation3. Final disconnect (topside)

HEAVY LIFT VESSEL (HLV)

1. Platform removal2. Transportation to shore

4

Progress to Date

*68% of wells (145), 68% of platforms (38)

3rd Party Operated

Chrysaor Operated

Ready for removal (platform)Flushed & cleaned (pipeline)

99 wells P&A’d*

LOGGSViking Bravo

Murdoch

All pipelines flushed and cleaned

7 platforms removed,

19 ready for removal*

Viking Bravo & LOGGS de-manned

TGT ready for demolition

Rigorous safety case management

20% reduction in campaign cost

28% reduction in well P&A cost

Careful environmental execution

5

Well P&A: Downward Cost Trend Continues

✓ Reduced rig rate

✓ Crew learning curve

✓ Well suspension from AWV

✓ Bunter formation flow testing

✓ Through-tubing abandonments

• Reduced need for logging

• Reduced completion pulling

• Fewer BOP runs

✓ Sabre conductor cut & recovery

✓ Offline work-scopes

✓ Rig modifications

Ensco 92

• CMS Area campaign in Q2 2019

• 4 operators, several joint ventures

• Integrated AWV & DSV campaign

• Flushing into Murdoch disposal well

• Commercial framework established

• Significant cost savings realised 6

Collaboration to Reduce Cost

Pipeline Cleaning Shared Subsea Campaigns Joint P&A Campaign

• Several operators involved

• Pipeline disconnects

• Conductor removals

• Surveys

• Debris clearance

• Shared mob/demob/weather risk

• Multi-well campaign by Spirit Energy

• Chrysaor KX well

• Cost savings from batch operations

and vessel sharing

7

2019 Boskalis-Scaldis Removal Campaign

Campaign ongoing for 9 platform removals and 1 subsea template

• OSV Da Vinci – rigging, preparation and supporting scopes across 7 platforms

• Bokalift 1 – 11 of 14 major lifts completed

• Gulliver – all 4 major lifts completed

KD LD GD DD CD HD ED UR JD

Topside Jacket Topside Jacket Jacket Jacket JacketSide

towersJacket Topside Jacket Topside Jacket Helideck Topside Jacket

Subsea

Template

Gulliver H1 H3 H2 H4

Bokalift 1 H6 H8 H6 H4+5 H1 D1 H D1 H D7 D5 H9 D

November 26, 2019

Great Yarmouth Disposal Facility

Bokalift 1OSV - Da Vinci Gulliver

VIKING ED TOPSIDE LIFT(21 AUGUST)

GULLIVER WITH VIKING LD TOPSIDE IN TRANSIT

(23 AUGUST)

VIKING CD JACKET

LIFT(8 OCT)

Looking Ahead

Ensco 92 P&A

Programme

Platform

Removals

Subsea

Campaigns

Oct Nov AugJulJunMayAprMarFebJanDec Sep

VM

Oct Nov FebJanDec AugJulJunMayAprMar Sep

November 26, 2019

TMTM

Murdoch

TD

CMS

2019

TGT

2020

RD – 12 wells

VM

CMS

Phase I: Cold Suspension

& De-manningPhase II: Site Demolition & Disposal

To

2025

2021

Murdoch ready for removal

Phase III: Land Remediation &

Restoration

To

2024

To

2024

To Q1

2022