next generation deepwater drilling...

New Generation Deepwater New Generation Deepwater Drilling RisersDrilling Risers

A Design MethodologyA Design Methodology

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September 29, 2004September 29, 2004 MTS DP ConferenceMTS DP Conference

IntroductionIntroduction

UltraUltra--deepwater, deepwater, 10,000 feet10,000 feet

1996 turning point1996 turning point Doubling water Doubling water

depth = depth = High Risk!!High Risk!! Existing Riser Existing Riser

Designs InadequateDesigns Inadequate What would the What would the

rigs look like?rigs look like?


Previous Alternatives for Deepwater?Previous Alternatives for Deepwater?

Limiting the mud weight Limiting the mud weight requirement;requirement;

Running thickerRunning thicker--walled, walled, higher strength (main higher strength (main tube) risers in the high tube) risers in the high stress regions;stress regions;

Investigations into lighter Investigations into lighter weight aluminum riser weight aluminum riser designs;designs;

Investigations into Investigations into composite risers;composite risers;

Upgrading shallow water Upgrading shallow water coupling designs with coupling designs with deeper couplingsdeeper couplings--limited limited to about 5,000 ft w.d.to about 5,000 ft w.d.

Design and Construct a Design and Construct a New Generation New Generation Deepwater RiserDeepwater Riser


Design ChallengesDesign Challenges

Manufacturing high strength connector Manufacturing high strength connector bolts;Bolt and thread capacity design bolts;Bolt and thread capacity design limits;limits;

Strength limitations of shallow water Strength limitations of shallow water connector designs connector designs

Careful consideration of riser pressure Careful consideration of riser pressure end load effects, PEL, on both auxiliary end load effects, PEL, on both auxiliary lines and main tube seals.lines and main tube seals.

Loop current and VIV effects on the Loop current and VIV effects on the riser;riser;

Hurricane abandonment strategies Hurricane abandonment strategies require emergency disconnect require emergency disconnect systems, riser hangsystems, riser hang--off and off and centralizing; centralizing;

Gas migration into the riser and Gas migration into the riser and deepwater well control issues require deepwater well control issues require gas handling equipment;gas handling equipment;

Riser mass limitations during running Riser mass limitations during running and outand out--ofof--phase heave acceleration of phase heave acceleration of vessel causing riser buckling after vessel causing riser buckling after disconnect;disconnect;

Lack of adequate riser buoyancy Lack of adequate riser buoyancy industry design standards;industry design standards;

Larger mud flow rate requirements Larger mud flow rate requirements because of higher pressure drops because of higher pressure drops across choke/kill auxiliary lines.across choke/kill auxiliary lines.


Enabling TechnologiesEnabling Technologies

Improvements in dynamic positioning Improvements in dynamic positioning of ultra deepwater drilling vessels;of ultra deepwater drilling vessels;

Improvements in thruster electroImprovements in thruster electro--mechanical drives;mechanical drives;

Availability of shipyards to design and Availability of shipyards to design and build tanker hulls as drillships.build tanker hulls as drillships.

Improvements in mooring winch Improvements in mooring winch systems for ultrasystems for ultra-- deepwater;deepwater;

Availability of high tolerance wall Availability of high tolerance wall seamed pipe;seamed pipe;

More efficient riser design analysis More efficient riser design analysis programs and FEA tools;programs and FEA tools;


Enabling TechnologiesEnabling Technologies The construction of a new riser The construction of a new riser

buoyancy plant in Houston;buoyancy plant in Houston;

Improvements in buoyancy Improvements in buoyancy manufacturing quality control;manufacturing quality control;

Improvements in fabrication of high Improvements in fabrication of high strength bolts for riser connectors;strength bolts for riser connectors;

Direct acting riser tensioner Direct acting riser tensioner technology;technology;

6060--inch rotary table development;inch rotary table development;

Riser gas handling technology;Riser gas handling technology;

Improvements in subsea control Improvements in subsea control system designs.system designs.


Water Depth/Tension ChallengeWater Depth/Tension Challenge

1,600/Type D1,900/Type E2,000/Type E2,400/Type F3,500/Type H

1,2001,6001,8002,0002,700

1012131416

Indicated Tension (kips)/API Rating

TSR (kips)

Mud Weight (ppg)

10-Yr GoM Storm

WD = 10,000 ft

1,450/Type D1,650/Type E

8001,200

1216

Indicated Tension (kips)/API Rating

TSR (kips)

Mud Weight (ppg)

10-Yr GoM Storm

WD = 5,000 ft


Riser ComponentsRiser Components

INTERMEDIATE FLEXJOINT

TENSIONER SUPPORT RING

TENSIONER

UPPER FLEXJOINT

DIVERTER

ROTARY TABLE

RISER SPIDER

RISER JOINTS

RISER BOOSTER LINE JOINT

LOWER FLEXJOINT


Mud Weight vs. Water DepthMud Weight vs. Water DepthMUD WEIGHT vs WATER DEPTH

Estimated Maximum Riser Operating Limits

PPG/10,000 FT 14ANALYSIS POINT

PPG/7,500 FT 16ANALYSIS POINT

-

2,000

4,000

6,000

8,000

10,000

12,000

14,000

13 14 15 16 17 18 19 20

MUD DENSITY, PPG

WA

TER

DEP

TH, F

T

10,000 FT BASE CASE 7500 FT 16 PPG REF CASE


Riser SystemRiser System

Telescopic jointTelescopic joint Tension support ringTension support ring HiHi--Press, Lg. Dia. C/KPress, Lg. Dia. C/K Riser CentralizerRiser Centralizer Riser Specialty JointsRiser Specialty Joints Gas Handling JointGas Handling Joint Buoyancy Required?Buoyancy Required? Riser Disconnect!!!Riser Disconnect!!!


Telescopic JointTelescopic Joint

Highly loaded jointHighly loaded joint 4 knot design current4 knot design current 100 kip shear at joint100 kip shear at joint 4,000,000 ft4,000,000 ft--lb bend.lb bend. Limiting angle of 8.5degLimiting angle of 8.5deg Centralizing requiredCentralizing required Protection for Aux. Protection for Aux.

LinesLines


Riser CentralizerRiser Centralizer

Emergency DisconnectEmergency Disconnect DriftDrift--off or Driveoff or Drive--offoff Riser Slipjoint CapturedRiser Slipjoint Captured Design for 100 kip Design for 100 kip

lateral riser loadinglateral riser loading


Gas HandlerGas Handler

Two AnnularsTwo Annulars Choke/Kill HosesChoke/Kill Hoses Control UmbilicalControl Umbilical


Buoyancy DesignBuoyancy Design

Module StrengthModule Strength Module Depth RatingModule Depth Rating Module LengthModule Length


Specialty JointsSpecialty Joints Intermediate flexjointIntermediate flexjoint Termination jointTermination joint


Gas In RiserGas In Riser

Gas Handler at topGas Handler at top Safety issuesSafety issues Design impactDesign impact Weight impactWeight impact Cost impactCost impact Reduced riser collapse Reduced riser collapse

riskrisk


DriftDrift--off Study Environmentsoff Study Environments

2.7 1.4 29.0 15.0 7.2 5.0 480001-year Winter Storm + 10 Yr Loop Current

0.7 0.4 35.5 18.3 7.1 4.6 380001-year Storm

1.2 0.6 42.7 22.0 8.2 5.8 2800010 year Winter Storm

ktsm/secktsm/secsecm

VelocityVelocity1 hour1 hourT meanHs

DPSIM CASE

SERIESEnvironment

Direction(s)

CurrentCurrentWindWindWave


Riser Disconnect Time LimitsRiser Disconnect Time Limits15001500 Water DepthWater Depth-- DRIFT OFFDRIFT OFF1500 ft Water Depth,Riser Angles vs. Vessel Offset and Time

1YR STORM + 10YR LOOP CURRENT, DRIFT OFF

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

15 30 45 60 75 90 105 120 135 150

Vessel Offset (ft)

Ris

er A

ngle

s (d

eg)

0

30

60

90

120

150

180

Tim

e (s

ec)

Time

Flexjoint Angle

Slipjt Angle

Linear (Time)

Slipjoint Angle Trend

Low er Flesjoint Angle Trend


Riser Disconnect Time LimitsRiser Disconnect Time Limits15001500 Water DepthWater Depth-- DRIVE OFFDRIVE OFF

1500 ft Water Depth, Riser Angles vs. Vessel Offset and Time1YR STORM + 10YR LOOP CURRENT

0.001.002.003.004.005.006.007.008.00

15 30 45 60 75 90 105 120 135 150

Vessel Offset (ft)

Ris

er A

ngle

s (d

eg)

0

30

60

90

120

150

180

Tim

e (s

ec)

TimeFlexjoint AngleSlipjt AngleLinear (Time)Slipjoint Angle TrendLow er Flesjoint Angle Trend


Riser Disconnect Time LimitsRiser Disconnect Time Limits75007500 Water Depth Water Depth DRIFT OFFDRIFT OFF

7500 ft Water Depth, Riser Angles vs. Vessel Offset and Time1YR STORM + 10 YR LOOP CURRENT, DRIFT OFF

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

75 150 225 300 375 450 525 600 675 750

Vessel Offset (ft)

Ris

er A

ngle

s (d

eg)

0306090120150180210240270300330360

1 2 3 4 5 6 7 8 9 10

% Vessel Offset

Tim

e (s

ec)

Time

Flexjoint Angle

Slipjt Angle

Linear (Time)

Slipjoint Angle Trend

Low er Flesjoint Angle Trend


ESD and DP Time LimitsESD and DP Time Limits

Wind Current TimeWater Depth

(ft) Hs Tmean 1 hour Velocity Maximumm sec kts kts Seconds

1500 5.0 7.2 29.0 2.7 135

1500 5.0 7.2 29.0 2.7 70

7500 5.0 7.2 29.0 2.7 360

Wave

1-year Storm+10 Yr Loop Current-Drift-off1-year Storm+10 Yr Loop Current--Drive-off1-year Storm+10 Yr Loop Current--Drift-off

Environment


The Future Beyond 10,000 ft?The Future Beyond 10,000 ft?

Composite Riser Technology?Composite Riser Technology? Dual Gradient Drilling Technology?Dual Gradient Drilling Technology? Slim Bore Riser Drilling?Slim Bore Riser Drilling?


It Does Happen!It Does Happen!Hurricane IvanHurricane Ivan--DP with RiserDP with Riser

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