Chevron U.S.A. Inc. Gulf of Mexico Business Unit Subsea ... · PDF fileGulf of Mexico Business Unit Subsea Engineering Team ... © Chevron 2010 DOC ID 9 High Pressure ... installed

DOC ID© Chevron 2010

Chevron U.S.A. Inc.Gulf of Mexico Business Unit

Subsea Engineering Team

Design, Construction and Performance of Subsea Production Flowlines in the

Blind Faith FieldGary Giordano

9 August 2010

DOC ID© Chevron 2010 2

Agenda

Overview of Chevron Assets in GoM

Blind Faith Subsea Development

Field Layout Selection

High Pressure High Temperature Flowlines Design

Flowlines and Accessories Fabrication

Installation of Flowlines System

Flowlines Pre-commissioning

Flowlines Performance


Blind Faith Overview

Chevron became operator of Blind Faith 1Q 2004

Chevron 75% & Anadarko 25%

Field located 160 miles SE of New Orleans, LA

Located in MC 695 & 696 in 7,000’ of water

Subsea Field Located 5 miles from Blind Faith Production Facility

Total length of flowlines loop is approx 10 miles

Blind Faith first oil was in November 2008


Suction PileChain

Sled (PLET)

Flowlines

Flowline Risers

Subsea Distribution Unit -

SDU

Umbilical

Manifold

Jumper

Flying Leads

Tree

Export Risers

7000 ft WD

Production Facility5 mile offset from well center

Buoyancies


Field Layout Selection

Field layout and length of flowlines were based on

Geohazard and geotechnical constraints

Flow assurance requirements

Required straight line length and curve radius past the riser touchdown point

Optimum length based on minimizing the impact of axial creeping and lateral buckling of the High Temperature flowlines

Environmental conditions for the selection of the orientation and location of the host



DESIGN BASIS

Design SITP 12.5 K, 300 F at mud line

Surface piping, flanges, Titanium Stress Joint (TSJ): 10 K, 250 F

Control upheaval and lateral buckling induced by product high temperature

Wet insulation applied for thermal management to maximize “No Touch” time to prevent hydrate plugging


High Pressure High Temperature (HPHT)

HPHT flowlines are more sensitive to the soil

Extensive HPHT flowlines analyses were undertaken

Independent verification was performed

The outcome of the analysis was used to define the Weld Defect Acceptance Criteria and the boundary conditions to the termination structures (PLETs)

The HPHT loads on the termination structures made the PLETs design and transition pieces challenging since several iterations with the designers and installation contractor were required


Special Flowline Design/Installation Considerations

Optimizing Pipe Weight – Design Pressure, On-Bottom Stability, Spanning, Buckling

Flow Assurance

Hydrate Remediation

Riser Hang Off System – Titanium Stress Joints versus Flex Joints

QA/QC for Girth Welds – Maximizing Design Strength and Operational and Installation Fatigue Life – ECA, AUT, Risers must be perfect

Installation Vessel Tension/Departure Angle required to retain Pipeline Catenary Shape

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DESIGN OUTCOME

90 ft long, 16 ft diameter suction piles were required to anchor each flowline

Buoyancies were used to control the lateral buckling induced by high product temperature

High density layered PP was required for the bottom sections of the risers

Total outside diameter of the 7-in flowlines was approximately 14 inches

Pre-layed configurations was designed to accommodate post installation of the risers


Installation Sequence Constraints

2. Gas Export Riser

1. Oil Export Riser

4. West Flowline Riser

3. East Flowline

Riser

5. Umbilical

Installation Sequence: 1, 2, 3, 4 , 5

Host


Flowlines and Accessories Fabrication

Pipe Fabrication and Coating

Buoyancies, Strakes, Titanium Stress Joints

PLETs

Suction Piles

Intervention Spools


Insulation Qualifications

Extensive qualification were performed for flowlines insulation and heavy insulation (weight coating) required near the riser sag bend


Pipe Fabrication and Coating

Pipe Fabrication at Spool Base(Scotland)

Mill Pipe Production(Italy)

Coated Pipe Transportation(Norway)


Flowline Accessories

Strakes(Netherland)

Flowlines Buoyancies(USA)

Titanium Stress Joint(USA)


PLETs Fabrication

PLETs Fabrication(Houston - USA)


Suction Pile Fabrication

Suction Piles Fabrication(Corpus Christi - USA)


Closing Spools Fabrication

Photos of flowline closing spools


Suction Piles

Pile penetration


Suction Piles Lessons Learned

Suction pile stopped penetrating and questions were raised on whether the soils were different at that location

It was found out that pressure gauge was not providing correct readings due to its location

Lesson Learned: Ensure the pile design includes a suction gauge close to the suction pile to provide accurate readings


PLETs Lessons Learned

Interface

Equipment Constraints


PLETs Lessons Learned

The PLET/flowline interface required many iterations between the fabrication and installation contractors to ensure the PLET fits the handling frame on the installation vessel

Lesson Learned: Evaluate critical interfaces very early in the project and work the issues as early as possible


Flowlines Installation

New build vessel was used to reel coated flowlines (14-inch total outside diameter)

Coated pipe was load-tested on tensioner before the offshore installation

Titanium Stress Joint mock up was used to ensure it fits within the vessel access constraints

PLET mock up was fabricated to help ensure it can be properly handled with the vessel equipment

Extensive installation analyses were performed to cover a wide range of weather conditions offshore


Titanium Stress Joints

Took longer than expected to fabricate

Required extensive interface with the installation contractor


Flowlines Jumpers Installation


Intervention Spools

Fitting


Risers Installation

Risers were installed with a newly build anchor-handling type vessel (WD approx 7000 ft)

600-mt risers pull in equipments were used to hang the risers in their respective baskets

Risers Pull-in Equipment on Platform


Subsea Offshore Campaign Vessels

Boa Sub CSeven OceansToisa VigilantChloe CandiesHarvey DiscoveryM/V Andrea Cenac/OC-260Maersk AchieverNormand CutterHOS DominatorVeolia -King FisherVeolia-Sword FishM/V John G. / Barge M960 AdriaticWarren Thomas M/V Miss Lis Karen Kobe /JMC 252 M/V Admiral Lee/JMC 184

Note: The list does not include geophysical, geotechnical, diving, and pre-commissioning vessels used to support the subsea scope of work.Note: The list does not include geophysical, geotechnical, diving, and pre-commissioning vessels used to support the subsea scope of work.

2008 Storms

Arthur

Bertha

Cristobal

Dolly

Edouard

Fay

Gustav

Hanna

Ike

Josephine


HPHT Flowline Performance

28

Original Simulation showed single mode buckle

Lateral Nodal Displacements With Two Engineered Buckle Sections @ Sta 130+00 and Sta 170+00 For 5 Startup Cycles

-40

-30

-20

-10

0

10

20

30

40

50

1000 1100 1200 1300 1400 1500 1600 1700 1800

Stations from Riser to PLET (10*ft)

Dis

plac

emen

t (ft)

As_Laid Hydrotest Startup_1 Startup_2 Startup_3 Startup_4 Startup_5

ST1

ST2

ST3 ST4

ST5

ST1


HPHT Flowlines Performance

29

Side Sonar Scan method was used to determine lateral buckling of flowlines after first oil


HPHT Flowline Performance

30

Side sonar scan survey post start-up showed a different mode response (2nd mode buckling shape)

Flowline deflections and stresses were determined to be within design requirements


Blind Faith Achievements

Blind Faith is Chevron first development in 7000 ft

Chevron first subsea development with SITP of 12.5 ksi, and product temperature over 280 F (300 F downstream of choke)

The flowlines were the industry first application of wet thermal insulation rated for 300 F that was installed using a reel lay vessel

Blind Faith is Chevron first application of Titanium Stress Joints for SCR's supported from a floating production facility

An anchor type vessel was used to install the risers at 7000 ft. This was first in the industry


Blind Faith Future Plans

Seafloor Gas Lift Major Capital Project Team established – Start up planned for 2013

Considering Downhole Gas Lift and Subsea Boosting

Additional Subsea Wells and Third Party Tie-backs are potential future options

Recompletion and Sidetracks of existing wells highly likely in later life

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Chevron U.S.A. Inc. Gulf of Mexico Business Unit Subsea ... · PDF fileGulf of Mexico Business Unit Subsea Engineering Team ... © Chevron 2010 DOC ID 9 High Pressure ... installed