FIELD DESCRIPTION

Located in the central and south east of Block 32

260km offshore Luanda, Angola

Water depth is about 1,900m.

Covers 800 sq. km. area

Estimated reserve of 650 million barrels of oil

ABYSS OFFSHORE FIELD DATA

Wave Height • 3.69 m (significant wave height)

Current Speed• 1.92 m/s(surface)• 0.4 m/s (seabed)

Wind Speed• 25.51m/s

SURF package • 300 km line pipe • 115 km umbilical • 6 hybrid production loops • 5 water injection lines • 1 gas export line

2 FPSOs•“Design 1 Build 2” concept•Converted VLCCs•2x115 kb/d oil•200 kb/d water injection•3.35 Mm3/d gas compression

SPS•59 (+6) vertical Xmas trees•20 production manifolds•Subsea production control system

Drilling & subsurface•1,900 m water depth•6 fields – 650 Mb – 800 km2•59 wells (23 sub-salt) – 2 rigs

Caril

Gengibre

Louro

Gindungo

Mostarda

Canela

TECHNICAL CHALLENGES

RESERVOIR CHALLENGES• LARGE WELL COUNTS (SMALL INDIVIDUAL RESERVOIR)

• LONG TIE BACKS

• SALT DOME MASKS

1) Low penetration rate

2) Corrosive

3) Creep occurrence

4) Shock and vibration

5) Sutures and variance

6) Casing collapse

7) High cost（ $10m-$25m）

TECHNICAL CHALLENGES

DRILLING

Salt movement will continue to load casing and may cause failure over time

GRAPHENE

• Graphene can be described as a one-atom thick layer of graphite.  • Graphene is the strongest, thinnest material known to exist.

HISTORY

• First patent for the production of graphene was filed in October, 2002 ("Nano-Scaled Graphene Plates”).

• In 2004 Andre Geim and Kostya Novoselov at University of Manchester extracted single-atom-thick crystallites from bulk graphite.

• Geim and Novoselov received several awards for their pioneering research on graphene, notably the 2010 Nobel Prize in Physics.

STRUCTURE

• It is the one-atom thick planar sheet of carbon atoms (graphite), which makes it the thinnest material ever discovered.

• 2-dimentional crystalline allotrope of carbon.

• C-C Bond length is 0.142 nm.

• Graphene Sheets interplanar spacing is of 0.335 nm.

“The miracle material set to revolutionize our world”

Graphene has low weight and high strength.

Graphene is defined as a two-dimensional (2D) nanomaterial consisting of one-atom-thick layer of carbon (C) atoms

Stronger than diamond - 300 times stronger than steel, yet incredibly flexible (Young's modulus of 1 TPa). Ultimate tensile strength 130 GPa. Poisson’s ratio 0.149

Lighter than steel or any composite. Density is 2200kg/m3

Harnessed with polymers and composites it could make numerous forms of industry safer and more economical.

The worlds most conductive material

Impermeable

Graphene Properties

MECHANICAL PROPERTIES

1. MECHANICAL EXFOLIATION :

This involves splitting single layers of graphene from

multi-layered graphite. Achieving single layers typically

requires multiple exfoliation steps, each producing a slice

with fewer layers, until only one remains. Geim and

Novosolev used adhesive tape to split the layers.

2. EPITAXY :

Epitaxy refers to the deposition of a crystalline overlayer

on a crystalline substrate and the graphene – substrate

interaction can be further passivated.

PRODUCTION METHODS

Sicilicon-based epitaxy technology for producing large

pieces of graphene with the best quality to date

EPITAXY EXAMPLES :

• Silicon carbide

• Metal substrates

• Copper Vapor Deposition ( CVD)

PRODUCTION METHODS

GRAPHENE BASED COMPOSITES

• Coating/Film/Paper Form

• Sandwich Form

• Bulk form

• Polymer-Graphene Composites

• Metal-Graphene Composites

• Ceramic-Graphene Composites

GRAPHENE BASED COMPOSITES

• Mechanical properties:

1) Stiffest (E > 1 Tpa),

2) Strength: >100GPa tensile strength (40 times >

steel).

• Morphology: 2D shape

Ideal reinforcement phases to make stronger and

tougher composites for various applications

GRAPHENE REINFORCED COMPOSITES

GRAPHENE COMPOSITE

• Volume Fraction• 92% Carbon Steel• 8% Graphene

• Rule of Mixtures

• Steel with enhanced propertiescomposite steel steel graphene grapheneX X V X V

COMPARISON

DensityYoung’s Modulus Poisson’s Ratio UTS

SALT MECHANICS

SALT MECHANICS

Rate of salt movement1.6 to 6.4 cm/year

SALT MECHANICS

Rate of salt movement1.6 to 6.4 cm/year

Drifts 1.28m in 20 years!

CONSEQUENCES

The problem…

• Casing deformation

In consequences…

• Instability

• Operation difficulties

• Increase in OPEX

• Well abandonment

• Shortened well life

• Incomplete recovery

MODELLING THE SALT

Specific Weight 143lbf/ft

Young’s Modulus 4.6E06 psi

Poisson’s Ratio 0.25

Thermal Conductivity 6.06 Btu/day in oR

Specific Heat 0.201 Btu / lbm-oR

Coefficient of Thermal Expansion 2.5E-05 oR

Density 2.165 gm/cc

Viscosity ∼1016 Pa s

STATIC ANALYSIS OF GRAPHENE CASING PIPE

Production Casing Design Isostacy Again: Explanation of Salt Movements, A. Lowrie, R. Hamiter,Lerche, K. Petersen, J. Egloff

The Description of a Process for Numerical Simulations in the CasingCementing of Petroleum Salt Wells – Part I: from drilling to cementingMackay, F. IBM Research - Brazil, Rio de Janeiro, Rio de Janeiro, Brazil

Idealised 2D Plane Strain model created using Finite Element software Ansys

CASE STUDY: MODELLING FOR THE ANALYSIS

oApproximated to a typical well in the Tupi field of the Pre-salt Campos basin in Brazil.

oThe true vertical depth (TVD) of the case study is 7000 m (22965.88 ft). The layer characteristics are as follows:

7000m

The vertical in-situ stress = 130.37 Pa Vertical Stress/Horizontal Stress = 1

Point of interest

Excess Estimated Pressure of 19613300 Pa

Graphs Ref: Isostacy Again: Explanation of Salt Movements, A. Lowrie, R. Hamiter,Lerche, K. Petersen, J. Egloff

CASE STUDY: MODELLING FOR THE ANALYSIS

Total pressure force acting on casing at point of interest: shear zone 7000m

Lowrie’s Estimate of excess pressure from salt migration over time

+Calculated pressure from vertical in-situ stresses

Initial drilling fluid weight required to balance in situ stresses is 15.8 ppg

150 MPa external pressure force

15.8 ppg gives 129.94 MPa internal pressure force

CASE STUDY: MODELLING FOR THE ANALYSIS

MATERIAL MODELSProperties

Graphene Composite + Steel P110 + Cement

Steel P110

E (Pa) 2.12E+11

n 0.3

Ultimate Tensile Strength (Pa) 862000000

Pure Graphene

E (Pa) 1.02E+12

n 0.149

Ultimate Tensile Strength (GPa) 130

Graphene Composite

E (Pa) 2.7664E+11

n 0.2879

Ultimate Tensile Strength (Pa) 862000000

8% Graphene

Approximately 30% increase in Young’s modulus

MODELLINGIn Ansys

oIdealised 2D Plane Strain model using solid plane 182 elements

oMapped mesh with global size of 0.001

oBoundary conditions: nodes constrained in y direction where y=0

oNodes constrained in x direction where x=0

STATIC ANALYSIS OF GRAPHENE CASING PIPE RESULTS

Graphene Composite Displacement Steel P110 Displacement

Displacement of 0.638 mm Displacement of 0.668 mm

Graphene Composite X component of Stress Steel P110 X component of Stress

Maximum Stress of -88700000 Pa Maximum Stress of -92700000 Pa

STATIC ANALYSIS OF GRAPHENE CASING PIPE RESULTS

Graphene Composite Y component of Stress Steel P110 Y component of Stress

Maximum Stress of -88700000 Pa Maximum Stress of -92700000 Pa

STATIC ANALYSIS OF GRAPHENE CASING PIPE RESULTS

Graphene Composite

Steel p110

0.62 0.63 0.64 0.65 0.66 0.67 0.68

Displacement

Displacement (mm)

Displacement (mm)

STATIC ANALYSIS OF GRAPHENE CASING PIPE RESULTS

Graphene Composite X- comp Stress

Steel p110 X-comp Stress

-94000000 -93000000 -92000000 -91000000 -90000000 -89000000 -88000000 -87000000 -86000000

X Component of Stress (Pa)

Stress (Pa)

STATIC ANALYSIS OF GRAPHENE CASING PIPE RESULTS

SIMPLIFICATIONS

Pure salt (without impurities)

Temperature:

Location Depth (from sea bed) Temperature

Top salt 2560 m 25.9 ℃

Mid salt 3430 m 48.9 ℃

Base salt 4175 m 65.6 ℃

Variables

Temperature

Time

linearly

Creep rate maximal rate: 6.4cm/yr from Lowrie’s research

However, not feasible

Treat linearly:

Location Depth Depth

Top salt 2560 m 34.45 Mpa

Mid salt 3430 m 52.89 Mpa

Base salt 4175 m 69.86 Mpa

SIMPLIFICATIONS

Time:

Bailey-Norton law (Creep rate law)

Where: A 1.05e-10 MPa^-nhr^-(m-1)

n 3.5

m 0.3

The final equation:

SIMPLIFICATIONS

Model:

Material: solid185

Material properties: based on the cross section data

Length: 1 m (mesh problem)

Boundary condition: fixed in all DOF at z=0fixed in Z direction at z=1

DEPTH

Steel Graphene compositeDeformed shape:Results:

DEPTH

Steel Graphene compositeVon Mises stress:Results:

DEPTH

Items 　 Steel (m) Composite (m)

Total displacement SMX 4.79E-08 3.47E-08

X displacementSMN -6.22E-09 -4.19E-09

SMX 2.15E-08 1.57E-08

Y displacementSMN -1.08E-08 -7.49E-09

SMX 1.08E-08 7.49E-09

Z displacement SMX -4.73E-08 -3.43E-08

Total results:

Displacement:

Von Mises stress:Items 　 Steel (Pa) Composite (Pa)

Von mises stress

SMN 1976.17 1857.92

SMX 37807.1 35646.4

DEPTH

Total results:Displacement:

Von Mises stress:

Direction Percentage(%)

X 26.98

Y 30.65

Z 27.48

Total 27.56

Von Mises 5.72

DEPTH

Model:

Structure: The same with the depth section

Formula: Creep rate law

Analysis type: Transient analysis

Full time: 1 minute

Time step: 0.01second

Results selection: Node 1913 for displacement Node 1 for Von Mises stress

TIME

Results: X direction displacement of node 1931:Steel Graphene composite

Similarities:

Sharp decrease8 seconds

Decrease of rate Almost constantLong period

Differences:Extreme value

0.6e-2

3.3e-2

0.45e-2

2.5e-2

TIME

Results: Y direction displacement of node 1931:Steel Graphene composite

Similarities:Similar trend: oscillate at the initial 6 seconds and then decrease Differences:The amplitude of oscillation of composite is smallerThe final stage of composite is not 0

2.5e-14 2.2e-2

2.3e-2 0.8e-2

TIME

Results:Von Mises stress of node 1:

Steel Graphene composite

Similarities:Almost the sameDifferences:Nothing obviously

6600e6 6600e6

1200e6 1200e6

TIME

REMARKS

Conclusions:Graphene composite(1) can decrease maximum displacements

(2) can reduce the gap between extreme value

(3) does not work well in stress reducing

(4) has similar but better performance when applied dynamic pressure

Recommendations:(1) Combination of variable time and depth (temperature)

(2) Real temperature

(3) Increase the length of model

(4) Full time: 1 or 10 hours

ANALYSIS OF GRAPHENE MOORING SYSTEM USING ORCAFLEX

BRIEF DESCRIPTIONS

• Spread Mooring system• Total 12 mooring lines• Total length is 2430 meter

PLAN VIEW

MAXIMUM EFFECTIVE TENSION

Mooring Line with Maximum tension

1 2 3 4 5 6 7 8 9 10 11 124200

4400

4600

4800

5000

5200

5400

5600

5800

4832 4860 48974794 4807 4830

5298 5282 52635353 5348 5341

5149 51475212

5110 5122 5144

5608 5591 55735662 5658 5651

Mooring line with maximum tension(kN) Tension (kN)

MAXIMUM EFFECTIVE TENSION( without Damage line )

Mooring Line having Maximum Tension

1 2 3 4 5 6 7 8 9 10 110

1000

2000

3000

4000

5000

6000

7000

4805 4845 4792 4811 4844

5610 5575 5533 5611 5596

4895

5449 5447 54825103 5129 5124

5968 58865453

5991 5894

Mooring line with maximum tension (KN) without damage line( line -11)

Tension (kN)

SURGE

Graphene Steel Composite

Abyss FPSO Surge

SURGE( without Damage line - 11 )

Graphene Steel Composite

Graphene Steel Composite

HEAVE

HEAVE( without Damage line - 11 )

Graphene Steel Composite

Abyss FPSO Heave

REMARKS

• In both analysis, Less effective tension on the mooring line.• Increased Pay Load Capacity .• Less material required.• No significant impact on the vessel motion.

PRODUCTION

Uncoupled Riser System

Free Standing Hybrid Riser (FSHR)• Decoupling vessel’s dynamic motion from vertical riser• Reduced fatigue loads compared to Steel Catenary Risers

(SCR’s)• Technology already in use by Total E&P in Girassol Oil Fields in

Angola. Installed by FMC Technologies.

ORCAFLEX MODEL AND ANALYSIS

Objectives:• Analysis carried out for steel vertical riser (hybrid tower)

• Analysis carried out for graphene composite vertical tower. (Properties of graphene composite calculated using the rule of mixtures)

• Comparison of results

0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0 1600.0 1800.0 2000.00.0

5000.0

10000.0

15000.0

20000.0

25000.0

30000.0

Effective Tension (kN) (Graphene Composite)Effective Tension (kN) (Steel)

Arc Length of Hybrid Tower (metres)

Effec

tive

Tens

ion

(kN

)VARIATION IN THE EFFECTIVE TENSIONS ALONG THE LENGTH OF

THE HYBRID TOWER AFTER A 3HOUR SIMULATION

0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0 1600.0 1800.0 2000.00.0

5000.0

10000.0

15000.0

20000.0

25000.0

Wall Tension on Graphene Composite vertical hybrid tower(kN)Wall Tension on Steel vertical hybrid tower (kN)

Arc Length of Hybrid Tower (metres)

Wal

l Ten

sion

(kN

)

VARIATION IN THE WALL TENSIONS ALONG THE LENGTH OF THE HYBRID TOWER AFTER A 3HOUR SIMULATION

0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0 1600.0 1800.0 2000.00.0

50000.0

100000.0

150000.0

200000.0

250000.0

300000.0

350000.0

400000.0

450000.0

Max von Mises Stress for Graphene Composite vertical hybrid tower (kPa)Max von Mises Stress for steel vertical hybrid tower (kPa)

Arc Length of Hybrid Tower (metres)

Von

Mise

s Str

ess (

kPa)

VARIATION IN THE VON MISES STRESS ALONG THE LENGTH OF THE HYBRID TOWER AFTER A 3HOUR SIMULATION

CONCLUSION

• Static Analysis

• Dynamic Analysis• 8% graphene composite can reduce the displacements significantly• 8% graphene composite does not work well on stress aspect

• A

Cost AssessmentIs graphene economically viable?

1 square cm graphene $100 millionP110 steel $500-$2500

Not practical?However…

Casing failure $10-$25 millionCorrosion cost $1.372 billion/yr….

High CAPEX, Low OPEX!!!

CONCLUSION