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11 April 2012

ENSCO 8500 Series®

Mark Burns

Senior Vice President – Western Hemisphere

David Hensel

Vice President – North and South America

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• Addressing “Heart of the Deepwater Market”

• Cost-effective design and operations predicated

on success of ENSCO 7500 delivered in 2000

• Leverage shipyard and vendor relationships

• Owner specified vs. owner supplied equipment

• Customer contract before shipyard contract

• Leverage customer relationships and workforce

• Compelling economics

• Win/Win/Win approach

Strategy

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Targeting the Heart of the Deepwater Market

0

100

200

300

400

500

600

1,000 - 2,999' 3,000' - 7,499' > 7500'

No

. o

f W

ells

Water Depth

Source: IHS ODS-Petrodata. Wells drilled since 2005 by ultra-deepwater semisubmersibles

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• Proven cost-effective design with enhanced operating

capabilities suitable for exploration and development

drilling programs

• Proven project management with demonstrated on

time delivery performance

• Equipment with value-added features based on

detailed customer input that also contains costs

• Deck layout facilitates customer equipment flexibility

Value Proposition

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Uniform Design Benefits

Spare Parts

ENSCO Rig 8500 8501 8502 8503 8504 8505 8506

Shipyard

Repair &

Maintenance

Common

Equipment

Training

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ENSCO 8500 Series® Technical Review

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ENSCO 8500 Series® Profile

Water Depth 8,500/10,000 ft

Rated Drill Depth

35,000 ft

Main Deck L x W

240 ft x 255 ft

Hull Dimensions L x W

310 ft x 56 ft

Classification DPS-2

Offline Activity Moon pool & drill floor

8 Hull Length 310’ by 56’ Wide

Quarters

150 beds

Main Deck

Height 97’

Length 240’

Substructure

Height 46’

Columns

Width 45’

w/rounded

corners

Profile Dimensions

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BOP Equipment

• Latest generation

• 1st to be recertified in GOM

• 6 rams compact 18-3/4” 15M

• 6th ram is a test ram

• Blind shear & casing shear ram

w/22” operators @ 5,000 psi

Subsea Equipment

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Design Efficiencies

• Ability to work offline on drill

floor and moonpool

• Ability to handle 93’ length of

drill pipe & casing on catwalk

• Multi-manipulator arm drill floor

• Electronic driller

• Dual oil base & water base mud

system

• Improved tree handling layout

• BOP test ram

• Riser hang-off/transit system

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ENSCO 8500 Series® Successes

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• Drilled in 7,200’ water depth

• Drilled to 33,814’

• Ran 13 5/8” casing string weighing 1.8 million lbs

• ENSCO 8503 operated at currents up to 5.8 knots in

French Guiana

• DWAT/Sea Trials – ENSCO 8503 completed in 49 days

(10 day improvement)

• Mobilization – ENSCO 8505 from Singapore to GOM in

39 days

Operational Successes

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• 1st rigs to be recertified in USGOM

• ENSCO 8500 worked at full day rate on allowed activities

• ENSCO 8501 first rig in USGOM to receive drilling permit

post-Macondo

• DOI visits rigs to highlight resumption of drilling in the

USGOM

Regulatory Successes

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Customer Successes

ENSCO 8500 Drills Anadarko’s

Major Lucius Discovery

ENSCO 8503 Drills Tullow’s

French Guiana Discovery

GRSS Meeting 5th March 2012

French Guiana – Zaedyus timeline

2010

15th February End of 3D seismic acquisition on Eastern Slope.

5th May Processed 3D data available in house.

25th September Zaedyus prospect selected; final location determined

14th December

Substantial revisions to well design are required in the light of evolving pore pressure fracture gradient predictions.

2011

9th February ENSCO 8503 departs Gulf of Mexico.

1st March ENSCO 8503 arrives on location

3rd March Drilling permit approved by Prefect

5th March Zaedyus spudded

9th September Press release, Zaedyus discovery

19th November ENSCO 8503 preparing for demobilisation

8th December Rig off contract in GOM

GRSS Meeting 5th March 2012

Zaedyus; Key Lessons (1/2)

• Excellent EHS performance by the team particularly ENSCO 8503 (new build); – more than 0.5 million man hours without an LTI and no environmental incidents

• ENSCO 8503 rig uptime 96.2% - good for newbuild

• Detailed pore-pressure modelling and monitoring – But onset of likely overpressure in the shale was not initially countered with sufficient mud-weight

• Main supply base in Port of Spain, Trinidad – Supplemented by Paramaribo e.g. hot shot airfreight, MGO

• Four supply boats utilised, incl. one fast vessel; no waiting time during entire operation – 3-4 days sailing one-way to Port of Spain

– Security of fuel supply critical; strike in Trinidad affected deliveries to Paramaribo

– Vessels only had 2,000bbl MGO capacity; 5,000bbl would have been better

• Cayenne office set-up ideal – Tullow and main service providers under one roof (with some segregation)

– Over the course of the well developed “Real Time” monitoring capability in Cayenne to assist decision making, in addition to Schlumberger Real Time Operating Centre (RTOC) in Houston

GRSS Meeting 5th March 2012

Zaedyus: a major challenge successfully executed

The result:

• All the challenges were eventually overcome to deliver a major discovery with no Lost Time Injuries or Environmental Incidents

• Sensitive environment; frequent over-flights, marine mammal observers, turtles etc.

• Success case – additional contingent side track & core, side wall coring & very extensive data acquisition

• But, initial well cost and time estimates were substantially exceeded

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ENSCO

8500

ENSCO

8501

ENSCO

8502

ENSCO

8503

ENSCO

8504

ENSCO

8505

ENSCO

8506

Standardization ̶ A Marketing Advantage

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Customer Testimonials

“Drilling operations with our new deepwater rig ENSCO

8501 exceeded expectations. We completed the well in

approximately 15% less time than expected and 20% below

planned cost.” Nexen 2Q10 Earnings Release

“…extraordinary drilling results on a very complex well

(>33,000’ sub-salt) while having a superb safety record.” Customer letter

“…thank each and every one of you for your dedication in

building a safety and performance culture that is next to

none.” Customer letter

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• 97% utilization for ENSCO 8500 Series® in 2011

• Revenue backlog exceeds $1.9 Billion

• IRR for Series well exceeds 15% hurdle even with

Macondo impact

• Delivered on-time and on-budget

Financial Successes

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Newbuild Report Card

Driller Total Returns Marketing

Cost &

Timing

ESV A B A

ATW B- C- B B

DO A- A B A-

NE C- C- B- F

RDC B- C+ B+ C

RIG B+ B B A

SDRL A A- A+ B+

Average B B B+ B-

Source: Credit Suisse

A+

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0

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200

300

400

500

600

0

100

200

300

400

500

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ENSCO8500

ENSCO8501

ENSCO8502

ENSCO8503

ENSCO8504

ENSCO8505

ENSCO8506

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rre

nt

Da

y R

ate

(in

$ t

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nds)

Co

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uction

Cost

(in

$ m

illio

ns)

Construction Cost Current Day Rate

Strong Financial Returns

Order

Date Sep. 2005 Jan. 2006 Sep. 2006 Jun. 2007 Apr. 2008 May 2008 Aug. 2008

Contracted

Date Sep. 2005 Jan. 2006 Sep. 2007 May 2008 Apr. 2011 Oct. 2011 Jan. 2012

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Strength of Contracts

Ensco plc

Fleet Status Report

16 February 2012

Monthly Changes

Bolded rig names and underlined text signify changes in rig status from previous report.

Segment / Region /

Rig Design

Water

Depth' (1) Customer/ Status

Day Rate $000′s

US Location

Est. Avail /

Contract

Change

Deepwater

North & South America (excluding Brazil) ENSCO 8500 Semisubmersible DP 8500/10000 Anadarko/Eni High 290s U.S. Gulf of Mexico Aug. 13

ENSCO 8501 Semisubmersible DP 8500/10000 Nexen/Noble Energy High 370s U.S. Gulf of Mexico Jun. 13

ENSCO 8502 Semisubmersible DP 8500/10000 Nexen Mid 490s U.S. Gulf of Mexico Jun. 13

ENSCO 8503 Semisubmersible DP 8500/10000 Cobalt Mid 540s U.S. Gulf of Mexico Dec. 13

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• Strategy has proven to be successful

• Customer acceptance even better than expected

• Excellent financial returns

• Standardization has become a hallmark of Ensco

Summary

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