Fairfield Energy – Dunlin Cluster Decommissioning Requirements

Dunlin Alpha Now

Dunlin Alpha Infrastructure Summary

• 500km NNE of Aberdeen, 151M water Depth

• First Production August 1978, COP June 2015

• Four Leg Concrete Gravity Base (CGB), weighing 320,000 mT

• Modular Topsides design supported by a steel box girder Modular Support Frame (MSF), 20,000 mT

• 45 Wells to be plugged and abandoned from platform (P & A Operations commenced Jan. 2016)

• Osprey Development has 12 subsea water injection and production wells tied back to Dunlin Alpha

• Merlin Development has 4 subsea water injection and production wells tie back to Dunlin Alpha

• The Project is in “Select Stage” with Comparative Assessments being undertaken. These slides are based on the “Reference Case” for the project.

• The Dunlin Alpha, Osprey and Merlin decommissioning project is a fully approved project with a definitive target timeline for execution.

Dunlin Alpha Modules

OFFICES/ FACILITIES

STORE ROOM

FABRICATION

SHOP

T6800 MUD

STORAGE TANK

REDUNDANT

EAST SIDE

LABORATORY

DRILLING

OFFICE PLQ

DEAERATOR

TOWER

GANGWAY

LANDING

PLATFORM

Dunlin Alpha 2021

• The bias is to treat this as a demolition project

• Safe, Environmentally Friendly and Cost Effective Solutions required

• Different commercial models required for this business but lots of opportunities in decommissioning

Fairfield Supply Chain Dunlin Decommissioning Objectives

• The Dunlin Area Decommissioning Project will be managed by the Fairfield Energy team in Aberdeen

• In planning, preparing and executing the decommissioning of Dunlin, Fairfield will ensure that all contracts are raised and administered in a consistent and effective manner and that they:-

– Adhere to the ethical and safety standards of the company

– Meet the requirements of legislation and any other relevant external organisations

– Are processed and awarded with tight and proper controls which will meet all stakeholder requirements

– Are focussed on the maximisation of safe, efficient and cost effective decommissioning service delivery

• Fairfield will also engage with the supply chain to identify effective technological solutions that are environmentally acceptable and safe.

• Close contract management will be critical to the success of this project specifically in the area of Variation Control. Clear and detailed Scopes of Work will be critical to the tendering process.

• Peer companies experiences have demonstrated the importance of appropriate up front technical studies to establish and work to mitigate the most significant technical challenges of the project.

Dunlin Subsea Architecture

Dunlin A Platform Decommissioning “Ref. Case” Work Breakdown

1. Operations Support Contractor – AmecFosterWheeler

2. Platform Drilling Contractor for Platform Well Abandonments - Archer

3. Platform Drilling Services for Platform Well Abandonments – Halliburton, Baker

4. Platform decommissioning structural engineering support - Atkins

5. Facilities Cleaning, De-oiling, Preparation

6. Subsea infrastructure removal (Dive Support and Construction Vessels)*

7. Flotel for final heavy lift preparation

8. Topsides Modules Structural Preparation & Removal (Heavy Lift Vessels)

9. Leg Navigation Aid Fabrication and Installation

10. Barges to support removal

11. Piece Small Removal

12. Onshore Yard Operators for topsides receipt and deconstruction

13. Ports and harbours

14. Material brokers

15. Hazardous Waste Disposal

Osprey & Merlin Decommissioning “Ref. Case” Work Breakdown

1. Well Planning and Engineering Services - Exceed

2. Subsea Tree Intervention Tool provision – One Subsea

3. Mobile Offshore Drilling Unit provision – Transocean 712

4. Subsea infrastructure removal Comparative Assessment – Xodus

5. MODU Drilling Services – (Out to tender)

6. Subsea infrastructure removal execution (Dive Support Vessels)*

7. Onshore Yard Operators for equipment receipt and deconstruction

8. Ports and harbours

9. Material brokers

10. Hazardous Waste Disposal

Major Decommissioning Contract Award Timings Summary

2015 2016

2018 2019

2017

2020

Platform

Wells P & A

Subsea

Infrastructure

Decommissio

ning

Comparative

Assessment

Platform

Well P & A

Drilling

Services

MODU Well

Engineering

Support

(Tendered)

Mobile

Offshore

Drilling Unit

(Tendered)

MODU

Drilling

Services –

Wireline,

Slickline,

Coiled

Tubing etc.

Subsea

Infrastructure

Removal

Execution

(Tendered)

Platform

Removal

Contractor

(Tendered)

Platform Topsides

Receipt,

Deconstruction

and Recycling

/Disposal

(Tendered)

Post Removal Beacon Structure Fabrication

and Installation (Tendered)

Post Removal

Seabed Clearance

Survey and

Certification

Flotel

(Tendered)

Subsea

Infrastructure

Receipt,

Deconstruction

and Recycling

/Disposal

(Tendered)

There are four potential methodologies for the removal of the Dunlin Topsides:-

1. Piece Small (Removal of the topsides by breaking the infrastructure down to units that can be lifted by the existing cranes onto Barges/Supply vessels and transferred onshore)

2. Reverse Engineering, separating and air gapping the platform modules so that they can be removed in a number of large lifts.

3. Hybrid a combination of 1. & 2. to varying levels.

4. Topsides Single Lift, removed in a single lift and transported onshore for disposal.

Fairfield intends to tender Hybrid (Piece Small & Reverse Installation), Full Reverse Installation and Single Lift. Tenders will be issued to those who have access to the Heavy Lift assets.

Asset preparation for removal is critical to minimise expensive delays and resultant variations. Availability windows have historically been tight for the heavy lift assets required and missing contracted windows can result in delays of 12 months or more (subject to market conditions).

Removal Methodologies

Removal Methodologies

Piece Small Single Lift

Reverse InstallationHybrid

Technical Challenges – Leg Cutting/Separation

Technical Challenges – Leg Cutting/Separation

Technical Challenges – (Leg Internals)

• Legs dry now will be flooded before cutting

• Cut needs to be timed close to the lift

• Avoid cutting then leaving for a winter season NUI

• Internal or external system ?

• Prepared then left in situ for later activation ?

• Diamond Wire ?

• Explosive ?

• Abrasive jetting ?

• Water jetting ?

• Chemical cutting ?

• Grout Removal and Bolt Splitting ?

• OTHER ?

Technical Challenges – Leg Cutting/Separation

Dunlin Flare System Plugging

Dunlin Flare System Plugging

• Flare system isolated from all wells

• To facilitate further separation sections need to be isolated (to avoid any hydrocarbons seeping from dead legs etc.)

• Low cost but effective solutions sought.

• Gel plugs ?

• Cement ?

• Purging & Venting ?

• Low cost mechanical barriers ?

• OTHER ?

• Initial quote for 3 flare system mechanical plugs £140K (not acceptable)

Technical Challenges – Pipework & Vessel Cleaning

Technical Challenges – Pipework & Vessel Cleaning

• Topsides vessel and pipework cleaning

• Minimisation of personnel confined space vessel entry

• Minimisation of manual handling

• Cleaning to levels limits to allow cutting (cold and hot)

• Waste handing solutions

• Objective decision making on what not to clean (what can be done onshore)

Field Layout

In Field Subsea Flexible Flowline/Jumper Flushing

Challenge Details

• Description

• Eight 6” in-field flexible flowlines (25m – 40m) of which:

• Four 6” in-field flexible flowlines connect four production trees to a common manifold, each line contains oil, water and methanol;

• Three 6” in-field flexible flowlines are connected to three production trees but are disconnected from the manifold, each line contains oil, water and methanol;

• One 6” in-field flexible is fully disconnected and open to sea.

• Objective

• Remove the contents of seven in-field 6” flexible flowlines prior to disconnection from the trees/manifold and recovery.

• Issues

• In-field flowlines isolated both ends,

• No receiving facilities at either end of the lines to allow through flushing,

• Contents must be removed with the lines in-situ and prior to recovery,

• Contents must remain contained at all times.

In Field Flexible Flowline/Jumper Flushing

Configuration Details

Flexible Status Length

P1Connected at TreeDisconnected at Manifold

25m

P2Connected at TreeDisconnected at Manifold

25m

P3Connected at TreeConnected at Manifold

25m

P4Connected at TreeDisconnected at Manifold

25m

P5Connected at TreeConnected at Manifold

40m

P6Connected at TreeConnected at Manifold

40m

P7 N/A N/A

P8Connected at TreeConnected at Manifold

40m

To Dunlin

Flanged tree

connection

(ex. P8 – Sonsub

ROV connector)

Oil sampling

points are

inoperable

Flowline Isolation

Valve

All disconnected

lines are fitted with

blind flanges and

bleed

arrangements

In Field Flexible Flowline Flushing

Flexible Details5 1/8” NB 5K ROV Operable Valve

Fitted on Manifold End of All

Flexibles

6” In-Field Flexible Jumper

Construction

In Field Flexible Flowline Flushing

Summary

The Dunlin Decommissioning Project is a large and technically challenging operation.

Recent North Sea decommissioning projects which have been effectively undertaken have focussed on the following aspects when working with the supply chain:-

• Appropriate technical studies conducted objectively

• Clear Defined Technical Scopes of Work

• Effective contract management and control of commercial and technical delivery

• Ensuring the correct vendor personnel are assigned to and remain on the project

• Development of good positive working relationships

• Co-location of vendor key personnel with the project team (can be accommodated by Fairfield)

• Dunlin and other pending decommissioning projects offer significant opportunities in this Industry !

Questions

Q & A