Deepwater Dual Gradient Drilling Overview

October 19th, 2011Jasmin BegagicBusiness Development Manager, Transocean

Outline

• Dual Gradient DrillingDefinition and General InformationDefinition and General InformationDGD CategoriesOngoing DGD ActivityBenefits

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Acknowledgements

• Special thanks to:IADC MPD CommitteeIADC Dual Gradient Drilling Sub-Committee

Richard R. Brainard, AGR and John C. Cohen, AGRRichard R. Brainard, AGR and John C. Cohen, AGRKen Smith, ChevronKristin Falk, Ocean Riser SystemsLuc de Boer Dual Gradient SystemsLuc de Boer, Dual Gradient SystemsJohn Kozicz, Transocean

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What is Dual Gradient Drilling (DGD)?

• IADC currently defines dual gradient as:the “creation of multiple pressure gradients within select sections of the annulus to manage the annular pressure profile Methodsthe annulus to manage the annular pressure profile. Methods include use of pumps, fluids of varying densities, or combination of these”

• Collection of techniques and varied equipment utilized to create the dual gradient pressure profile

• DGD is a specific type of MPD

• These DGD technologies are applicable offshore to either floater MODU, jack-up MODU or fixed platform facility (SPAR, TLP, etc.) application

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What is Dual Gradient Drilling (DGD)? • IADC currently defines dual gradient as:

the “creation of multiple pressure gradients within select sections of the annulus to manage the annular pressure profile. Methods include use of pumps, fluids of varying densities, or combination of these”

• DGD is a specific type of MPD

• These DGD technologies are applicable offshore to either floater MODU, jack-up MODU or fixed platform facility (SPAR, TLP, etc.) application

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The Importance of DeepwaterIndustry Production from DW is Moving DeeperI i N b f W ll Industry Production from DW is Moving Deeper

at an Increasing Pace (Source: Chevron, Oct-07)Increasing Number of Wells

Drilled in 1,000m+ WD

43% Wells in 1,000+ m WDData Source: Wood Mackenzie,11-Oct-11 Source: P. Hansen, Chevron, Deepwater Technology Challenges, 9-Oct-07

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52% Wells in 1,000+ m WDData Source: Wood Mackenzie,11-Oct-11

Access to deepwater reserves can be challenging and Dual Gradient Drilling can help

• Narrow margins between pore and fracture pressures:

Well control eventsBallooning (losses / gains)

• Need for better management of wellbore pressures

• The Solution: Dual Gradient Drilling Ballooning (losses / gains)Excessive mud circulation timeRemedial cement jobs

• Estimated NPT 20% - 30% of total NPT• Some wells never reach targets• Some wells never reach targets

High development costsPotential loss of leases

7Source: J. Keith Couvillion, Chevron, Stretching The Technology Envelope (GOM), 23-Jan-08

While regular MPD techniques may help in many cases, DGD is used to ‘walk the line’

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Mudcap lets us drill this

Dual Gradient Drilling: Not A New Idea“Riserless” mud recovery Gas Lifted Riser Pumped Riser ReturnRiserless mud recovery Gas Lifted Riser Pumped Riser Return

• First patent in 1957

• Different Motivators:Driven by rig limitations inDriven by rig limitations in the 50’s and 60’sDriven by drilling problems in the past two decades

Delta VisionDeep Vision Subsea Mudlift Drilling (SMD)1

decades

9(1) - Courtesy of SMD JIP / Tested on the Diamond Offshore Ocean New Era

Dual Gradient Drilling Categories(1) Top Hole – Riserless (ex: “Pump and Dump”)(2) Post BOP (with marine drilling riser)

Dual Gradient – Subsea PumpDual Gradient Subsea PumpControlled Riser Mud LevelDual Gradient / Mix Fluid using GasDual Gradient / Mix Fluid using Liquid / HGSDual Gradient / Mix Fluid using Liquid / HGS

10 Source: Dual Gradient Systems LLC

Top hole riserless DGD• Alternative to traditional “Pump and Dump”

operations • Replaces riskier “Riser Pin and Connector”

tioperations • AGR offers its Riserless Mud Recovery

(RMR™) system for this application• Proprietary IPProprietary IP • Enabling technology • Top hole riserless DGD is now maturing in the

shallower water depths• Good industry uptake of over 150 wells by

over 25 Operators in the last 7 years• Both over the side and moon pool deployment

systems are available for up to 5 000’ (1 500systems are available for up to 5,000’ (1,500 m) WD

• Includes successful applications around the world in up to 4,657’ (1,419 m) WD

11Courtesy of: AGR

RMR™ Benefits• Enhanced Influx/Lost Circulation Detection

Faster reaction to shallow flowsFlow check possible anytime

I d Miti ti f Sh ll H d• Improved Mitigation of Shallow HazardsWeighted mud allows drilling between pp/fpEnsures the capability to meet planned casing setting depthsMay enable top hole to be drilled in area of medium risks

• Improved HSEReductions of discharge cuttings and drilling fluids to seabed

• Engineered Drilling FluidEngineered Drilling FluidControl of Trouble Zones through correct mud properties

• Closed Circulation SystemProvides volume controlAbility to complete hole section without running out of mudImproved open hole times for sensitive formations

• Improved Wellbore Construction

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Gauge Hole - fewer washoutsImproved Cement Jobs

Courtesy of: AGR

Presently, there are four different approaches to Post BOP Dual Gradient Drilling:

13*Note: These systems can be classified as, “Controlled Riser Fluid Level” systems under the IADC MPD Screening tool under developmentSource: Ken Smith, IADC Dual Gradient Drilling Workshop, May 2011

Continuous Annular Pressure Management (Transocean)• Light drilling fluid is pumped down the annulus

formed between the drilling riser and an inner riser (example: 16” casing string) or using dedicated booster lines.

• It mixes with the return mud from the wellbore and creates a lighter density mud in the drilling riser.

• The mud is processed through centrifuges to separate into the light dilution fluid and the heavier drilling fluid.

• Installed on the Discoverer Enterprise in JulyInstalled on the Discoverer Enterprise in July 2009 / The system is ready for use on Transocean Enterprise class rigs or other rigs with some modification.

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CAPM™ - Riser Degas and MPD Applications

15US patents: 6,273,193 and 7,866,399

Riser Degas MPD CAPM™

SubSea MudLift Drilling (GE/Hydril)• A sea-water driven positive

displacement pump (MLP) is located above the BOP/LMRP. It withdraws the mud from the well and pumps it back to thewell and pumps it back to the surface through a line attached to the drilling riser.

• The riser is filled with a seawater-density fluid, or the mud/riser fluid interface can be maintained at any depth.

• A Subsea Rotating DeviceA Subsea Rotating Device (SRD) sits above the MudLift Pump which can be used to rapidly change the pressure profile in the well.

16Courtesy of: Chevron

Controlled Managed Pressure (AGR Subsea)

• A subsea pump is suspended from the rig and placed near the seabedseabed

• The pump withdraws the mud from the well above the BOP/LMRP and returns it to theBOP/LMRP and returns it to the rig through an external line

• The riser is filled with “blanket fluid”fluid

• Field trial is planned using disc pump (head-pump)

17Courtesy of: AGR

The principle of Annular Level Control Low Riser Return System (LRRS)TM

• Partially filled Riser

Single Mud Gradient

Top part purged with Nitrogen

A simple pressure controls technology

• Mud is returned via a Subsea Mud Pump

• The Control System monitors the level and controls the pump

• BHP can be changed in minutes (instead of hours) by adjusting the level

A pump is suspended from the rig to a fixed depth in the seawater column

The mud is withdrawn from the wellbore and returned to the rig through adjusting the level

• Both a Managed Pressure Drilling and a Managed Gradient Drilling system

• LRRS Matches the Drilling Window

columnan external line

The riser is evacuated and flushed with nitrogen, and

• The system is under construction / Ready mid-2012 (est.)

BHP

t oge , a dthe gas/fluid interface in the riser is managed

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LRRS provides fast and efficient pressure management under complex pressure regimes

Courtesy of: Ocean Riser Systems

LRRS: Different ApplicationsLRRS +LRRS ECD LRRS HP

All All Deep and ultra deep

ReservoirSurface csg to reservoir Entire well Well sections

Water depth

Reservoir (exploration)

As conventional New procedures

Minimal rig integration Up scaling of “ECD” Deep water w/ smaller rigs

New procedures

Well sections

Well control proceduresOther

1919

Minimal rig integration Up scaling of ECD smaller rigs

Courtesy of: Ocean Riser Systems

Post BOP Dual Gradient Drilling Benefits• Safer wells

Improved process monitoring In some cases, ability to implement Riser Degas and Managed Press re Drillingand Managed Pressure DrillingImproved Riser Margin and Kick Tolerance

• Reduction in Non Productive TimeI d llb t U

CTI

ON

Hig

h Exploration

Improved wellbore pressure managementReduced or eliminated mud lossesSimplified well designPossibly fewer casing strings C

ON

STR

RIS

K

Development

Can reach deeper targets / drill “unreachable” wells

• Development Drilling

WEL

L Lo

w

PROJECT COSTLow High

Improved drilling efficiency and well productivityGreater production NPV and lower upfront Capex

Et

PROJECT COST

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• Etc…