TECHNICAL PAPER - 2H Offshore...DNVGL-ST-F201 (2018) API-RP-17G (2006) ASME II Part D (2015) ASME B31.8 (2007) Learn more at HPHT Riser Design Drivers –Steel Pipe Wall Thickness

TECHNICAL PAPER

Understanding HPHT Riser

Design Limits for Deep and

Ultra Deep Water

P. Padelopoulos, R. Thethi, W. Mo

World Oil HPHT Drilling Conference September 2019

Learn more at www.2hoffshore.com

Understanding HPHT Riser Design Limits for Deep and Ultra Deep Water

Peter Padelopoulos, Weihua Mo, Ricky Thethi

Snr Principal Engineer

2H Offshore


Agenda

• Introduction

• Riser Configurations

• HPHT Riser Design Drivers

• Technology Readiness Status Heat Maps

• Summary


Introduction

• Operators are looking to drill and develop deep water wells with high pressure >15ksi and high temperature >300°F

• Designing for HPHT conditions presents a number of engineering challenges which is stretching the conventional subsea technologies to their limits – Pipe manufacture reliability– Riser payload for installation and on host vessel

• The feasibility of 8" & 10" production risers subjected to HPHT conditions assessed on a quick ‘look-up’ technology readiness status chart are summarized in this presentation

Image Ref: OTC-28624-MS HPHT Riser Technology Challenges


Example of Steel Catenary Riser (SCR) Example of Steel Lazy Wave Riser (SLWR)

Riser Configuration - Catenary

• Catenary riser configurations can consist of steel or flexible pipe construction

• Configuration may comprise of a simple catenary or lazy wave

• Risers interface with semi-submersible, Spars, TLPs, FPSO’s


Tensioner System

Lower Riser System

Upper Riser System

Riser Configuration – SVIR• Single Vertical Import Risers

(SVIR) – Single or Dual Casing Tensioned via a Tensioner System

• Comprise of multiple interfaces and wide range of hardware packages

• Shell Perdido Spar, GoM, 8,000 ft water depth

• Chevron Genesis Spar (Export), 2,614 ft water depth

• Exxon Marimba (Pipe-in-Pipe with mechanical connectors) tied back to Kizomba TLP, West Africa, 3,900 ft water depth


Riser Configuration – FSHR

• Free Standing Hybrid Risers – Dual or Single Casing Tensioned via Buoyancy Tank

• To date FSHRs globally consist of a welded construction. Alternative approach to use high strength steel with non-weldable mechanical connectors

• Petrobars Cascade Chinook, GoM, 8,190 ft water depth

• Exxon Kizomba B (Pipe-in Pipe), West Africa, up to 4,200 ft water depth

• Interface with high motion vessels such as FPSO’s, shallow draft semi-submersibles


HPHT Riser Design Drivers – Global Design Parameters

• High pressure and high temperature

• Riser diameter – increase results in thicker wall

• Vessel motions - draft, strength, fatigue motions, hull VIM

• Water depth - shallower impacts TDP, deeper impacts the top

• Sour service – Knock down factors

• Acid stimulation - spent acid flowing back through SCR


HPHT Riser Design Drivers – Steel Pipe Wall Thickness Considerations

• Wall thickness to be per 30 CFR 250.1002

• Material strength de-rated due to temperature

• Per NTL 2009-G28, API RP 1111 can be used to calculate wall thickness due to internal pressure– API RP 1111 specifies to use

ASME B31.8 for de-rating

• Temperature de-rating for actual material is difficult to come by without project specific data

48.0

50.0

52.0

54.0

56.0

58.0

60.0

62.0

64.0

66.0

50 75 100 125 150 175 200 225 250 275 300 325 350 375 400

Yie

ld S

tre

ng

th (

ksi)

Temperature (°F)

STEEL YIELD STRENGTH TEMPERATURE DERATINGAPI 5L X65 Steel (SMYS=65.3ksi)

DNVGL-ST-F201 (2018) API-RP-17G (2006) ASME II Part D (2015) ASME B31.8 (2007)


HPHT Riser Design Drivers – Steel Pipe Wall Thickness Considerations

• To minimize wall thickness the following can be utilized:– Select appropriate temperature de-rating factor– Include NTL 2009-G28 to reduce surface pressure

by using gas head– API RP 1111, Appendix B, use 0.5 burst co-efficient

instead of 0.45. A number of requirements are stipulated to be conducted in production; • Full-length helical UT inspection of each length,

including UT wall thickness measurement• Specified minimum wall thickness greater than or

equal to 90 % of nominal• Mechanical properties to be tested with an

acceptable quality level = 0.10 %• Burst testing Image Ref: OTC-28624-MS HPHT Riser

Technology Challenges


HPHT Riser Design Drivers – Steel Pipe Wall Thickness

• Challenge and limitations associated with the large wall thicknesses pipe

– Optimizing the micro alloy composition to achieve required mechanical properties

– Meeting hardness values for sour service applications

– Pipe inspection and quality control of production of heavy wall pipe

– Excessive hydrostatic pressures and effect on pipe mills equipment/capabilities

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

2.20

15,000 psiX65

17,500 psiX65

20,000 psiX65

15,000 psiX70

17,500 psiX70

20,000 psiX70

Wa

ll T

hic

kn

ess (

inch

)

10 inch OD, Wall Thickness Sizing for Different Ranges of Design Pressures and Temperatures

250 °F 300 °F 350 °F

Existing Technology Limit = 1.9inch

Ref: OTC-28624-MS HPHT Riser Technology Challenges


HPHT Riser Design Drivers – Flexible Pipe Limitations

• Internal pressure capacity defined by Pressure*ID

• Flexibles under 6inch, 20ksi and up to 300°F qualified

• Ultra deep water flexibles prone to collapse restrictions, thus eliminating flexible risers– Currently 10’’ at 6,890ft for

sour service

• Multiple smaller lines would be required for FSHR and SVIRs– Issues with top of riser offtake

design

– Pigging multiple linesNote: 100MPa = 14.5ksi, 140MPa = 20ksiRef: 2010 - Deepwater Production Riser Systems & Components, Offshore Magazine


HPHT Riser Design Drivers –Installation Vessel Limitations

Ref: OTC-28624-MS HPHT Riser Technology Challenges

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5000 7500 10000 12500

Ris

er

To

p T

en

sio

n (

kip

)

Water Depth (ft)

INSTALLATION TENSION REQUIREMENTS vs WATER DEPTHX65 Production Risers, 350 °F Design Temperature, 12° Hang-off Angle,

Riser Filled with Seawater

8inch OD-15ksi 8inch OD-17.5ksi 8inch OD-20ksi

10inch OD-15ksi 10inch OD-17.5ksi 10inch OD-20ksi

Reel lay tension limit = ~2,200kip

S-Lay tension limit = ~3,300kip

J-Lay tension limit = ~4,400kip


HPHT Riser Design Drivers – Riser Components

• Flexible Joints have been used up to approximately 13 ksi design pressure and 250 °F design temperature. – Concern with elastomeric elements at higher temperatures

• Steel Tapered Stress Joint could be challenging due to limits on forging length, wall thickness, weight restrictions and loads into vessel

• Titanium Stress Joint should not be directly injected with fresh hydrofluoric (HF) acid. HF spent acid flowback tests from multiple operating fields confirm no attack on titanium TSJs

• As an alternative to thick walled steel pipe alternative technology such as composite pipe may be considered, although no track record for production risers– Lightweight, high strength, pressure upto 20ksi and temperatures to 300°F

– Magma Global (m-pipe) and Airborne

Flexible Joint

Composite Pipe

Tapered Stress Joint


Technology Readiness Status Heat Maps - SCRs

• Heat map10,000ft*

3 3 3 3 3 3 3 2 3 1 3 1 3 1 3 1 3 1 3 1 2 1 2 1

8,000ft*

4 3 4 3 4 3 4 2 3 1 3 1 3 1 3 1 3 1 3 1 2 1 2 1

6,000ft*

4 3 4 3 4 3 4 2 3 1 3 1 3 1 3 1 3 1 3 1 2 1 2 1

4,000ft†

4 3 4 3 4 3 4 2 3 1 3 1 3 1 3 1 3 1 3 1 2 1 2 1

3,000ft†

4 3 4 3 4 3 4 2 3 1 3 1 3 1 3 1 3 1 3 1 2 1 2 1

8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10"

High Uncertainty to Pass Qualification Qualification Stretch Qualified (Not Used) Field Proven

* Reaches water depth limits of current pipe lay vessels (9,800ft) and/or tension capacity limit (depending on pipe lay methods)

† Potential fatigue issues at touch down zone of SCR, especially in riser pipe inner diameter due to sour service

Key Technology Limitations: • Pipe wall thickness • Weldability • Sour Service

Based on Pipe Wall Thickness and Weldability

250°F 300°F

Steel Grade X65 for High Pressure High Temperature Offshore Risers

400°F

15,000psi 17,500psi 20,000psi

Technology Readiness Status – Steel Catenary Riser / Steel Lazy Wave Riser

350°F 400°F 250°F 300°F 350°F250°F 300°F 350°F 400°F


Technology Readiness Status Heat Maps – Flexible Riser

• Heat map

10,000ft1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

8,000ft1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

6,000ft3 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

4,000ft3 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

3,000ft3 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Bore ID 5" 7" 5" 7" 5" 7" 5" 7" 5" 7" 5" 7" 5" 7" 5" 7" 5" 7" 5" 7" 5" 7" 5" 7"


* Potentially one or two replacement campaigns over 20+ field life span

Key Technology Limitations: • Internal pressure capacity • Design temperature limit • Collapse water depth

350°F 400°F

15,000psi 17,500psi 20,000psi

300°F 350°F 400°F 250°F 300°F250°F 300°F 350°F 400°F 250°F

Technology Readiness Status – Flexible Production RiserBased on Internal Pressure Capacity and Temperature Limit


Technology Readiness Status Heat Maps – FHSR

• Heat map

10,000ft3 3 3 3 1 1 1 1 3 1 3 1 1 1 1 1 3 1 3 1 1 1 1 1

8,000ft *3

*3 1 1 1 1 3 1 3 1 1 1 1 1 3 1 3 1 1 1 1 1

6,000ft *3

*3 1 1 1 1 3 1 3 1 1 1 1 1 3 1 3 1 1 1 1 1

4,000ft *3

*3 1 1 1 1 3 1 3 1 1 1 1 1 3 1 3 1 1 1 1 1

3,000ft *3

*3 1 1 1 1 3 1 3 1 1 1 1 1 3 1 3 1 1 1 1 1

8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10"


* Multiple flexible jumpers required to meet the pressure rating requirement and provide required flow area

† Envelope may be expanded with the use of non-welded premium connectors

Key Technology Limitations: • Non-weldable mechanical connector • Surface jumper assembly • Subsea rigid jumper assembly

15,000psi 17,500psi 20,000psi

Technology Readiness Status – Free Standing Hybrid RisersBased on Flexible Surface Jumper Limits and Welding X65 Steel Pipe Limits

250°F 300°F 350°F 400°F 250°F 300°F 350°F 400°F 250°F 300°F 350°F 400°F


Technology Readiness Status Heat Maps – SVIR

• Heat map

10,000ft3 3 3 3 1 1 1 1 2 2 2 2 1 1 1 1 2 2 2 2 1 1 1 1

8,000ft3 3 3 3 1 1 1 1 2 2 2 2 1 1 1 1 2 2 2 2 1 1 1 1

6,000ft3 3 3 3 1 1 1 1 2 2 2 2 1 1 1 1 2 2 2 2 1 1 1 1

4,000ft3 3 3 3 1 1 1 1 2 2 2 2 1 1 1 1 2 2 2 2 1 1 1 1

3,000ft3 3 3 3 1 1 1 1 2 2 2 2 1 1 1 1 2 2 2 2 1 1 1 1

8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10" 8" 10"


* Deepwater SVIR system for mild sour service and with 17.5ksi and beyond is a technology challenge for most SVIR components.

Key Technology Limitations: • Non-weldable mechanical connector • Flanges • Surface Jumper Assembly • • Subsea Rigid Jumper Assembly • Tieback Connector

15,000psi 17,500psi* 20,000psi*

Technology Readiness Status – Single Vertical Import RiserBased on SVIR Component Technology Readiness

250°F 300°F 350°F 400°F 250°F 300°F 350°F 400°F 250°F 300°F 350°F 400°F


Summary

• Riser design for HPHT conditions is challenging

• The key driver is riser wall thickness and impact on manufacturing reliability, installation and payload on host vessel

• NTL 2009-G28 and API RP 1111, Appendix B should be utilized for riser wall thickness design

• SCRs or SLWR offer the most feasible riser configuration for HPHT conditions


Questions


Documents

TECHNICAL PAPER - 2H Offshore...DNVGL-ST-F201 (2018) API-RP-17G (2006) ASME II Part D (2015) ASME B31.8 (2007) Learn more at HPHT Riser Design Drivers –Steel Pipe Wall Thickness